MXPA98004839A - Accumula - Google Patents

Abstract

The present invention relates to: An accumulator that is capable of preventing an excessive increase in the flow rate of a liquid refrigerant that is discharged from the accumulator, reducing the amount of refrigerating machine oil that is accumulated in the accumulator, and maintaining a required amount of oil for refrigerating machine in a compressor. The liquid and a gas circulating in the refrigeration and air conditioning circuit are introduced into a first space 1 by means of a suction pipe 3, and the refrigerant gas is discharged to a refrigeration and air conditioning circuit through a passage pipe. gas 4, a second space 2 and a discharge pipe 5. Moreover, the elements that maintain the level of the liquid 7 and 8 prevent the elevation in height of the accumulated liquid introduced into the first space 1. When the height has not been made lower than a predetermined height, the gas communication element 4 moves the liquid in the first space from the first space 1 to the second space 2. In addition, a return element 6 discharges the refrigerating machine oil accumulated in the first space 1 to the refrigeration and air conditioning circuit

Description

ACCUMULATOR The present invention relates to an accumulator for forming a refrigeration and air conditioning circuit for use in an air-conditioning machine or a refrigerator. A conventional accumulator for forming a refrigeration and air conditioning circuit using, for example, a refrigerant, R22, and mineral oil (refrigerating machine oil) having mutual solubility will be described at this time. Figure 31 is a vertical cross-sectional view showing the structure of a representative accumulator described in a document ("Closed Compressor" written by Mutsuyoshi Kawahira, edited by Japan Refrigeration Association, July 30, 1981). Referring to the drawing, the reference numeral 151 represents a container, 152 represents a suction tube, 153 represents a discharge tube and 153a represents an oil recovery hole formed in the bottom portion of the discharge tube 153. The numeral reference 153b represents an inlet opening of the discharge tube 153. Reference numeral 154 represents a liquid refrigerant (in a state in which the refrigerating machine oil is dissolved) having a soluble relationship with the refrigerating machine oil that is accumulates in container 151. Reference numeral 155 represents a refrigerant gas. The operation of the previous accumulator will now be described. In a refrigeration and air conditioning circuit including the accumulator, the refrigerant gas 155 and the liquid refrigerant (including the refrigerating machine oil) 154 flow through the suction tube 152, and then, and then they are introduced into the container 151 as indicated by an arrow A. In the interior space of the container 151, the refrigerant gas and the liquid refrigerant (including the refrigerating machine oil) 154 undergo a process to separate the gas and the liquid from each other. Then, the refrigerant gas 155 is allowed to flow from the inlet opening of the discharge pipe 153b, to pass to the discharge pipe 153, and then discharges to the outside of the container 151. On the other hand, the liquid refrigerant (including the oil for refrigerating machine) 154 accumulates in the lower portion of the container 151. Then, the refrigerating machine oil dissolved in the liquid refrigerant (which includes the refrigerating machine oil) 154 is allowed to pass through the oil recovery hole 153a and, together with the refrigerant gas 155 and the liquid refrigerant including the refrigerating machine oil) 154 is allowed to flow to a compressor as indicated by an arrow B. The size of the oil recovery hole 153a is determined so that the oil recovery for Refrigerating machine can be done with confidence. Now, the problems experienced with the conventional accumulator shown in Figure 31 will be described. When the refrigeration and air conditioning circuit is operated, a state is realized in which the liquid refrigerant (including the refrigerating machine oil) 154 accumulates in the container 151 as shown in Figure 31 depending on the status of the operation. The flow rate of the liquid refrigerant (including the refrigerating machine oil) 154 flowing from the oil recovery hole 153a into the discharge tube 153 is increased until the flow velocity of the gas flowing in the discharge tube 153 rises and according to the amount of the liquid refrigerant that accumulates in the container 151 is increased, that is, according to the height H of the liquid refrigerant is increased. The characteristic of the flow regime achieved when the gas velocity is made constant is shown in Figure 32. In the drawing, the axis of the abscissa marks the height H (millimeters) of the liquid refrigerant and the axis of the ordinate marks the flow rate (kilograms / hour) of the liquid refrigerant (including refrigerating machine oil) 154 that is introduced from the oil recovery hole 153a into the discharge pipe 153. The flow rate from the recovery hole of the 153a oil is a value obtained by adding a flow regime, which is substantially proportional to the square root of the height H (millimeters) of the liquid refrigerant, with respect to a substantially constant flow regime. Note that the height H of the liquid refrigerant is a height from the oil recovery hole 153a to the liquid refrigerant 154. It is a known fact that the refrigerant gas discharged from the accumulator discharge tube in the refrigeration and air conditioning circuit , it is sucked by the compressor. Then, the refrigerant gas is compressed, and then discharged. The accumulator having the conventional structure encounters a phenomenon that the flow rate of the liquid refrigerant which is introduced into the discharge tube 153 of the accumulator is excessively increased if the liquid refrigerant 154 accumulates in a large quantity in the container 151. At this time, the compressor is brought to a state in which it sucks the liquid refrigerant in large quantity. As a result, the state in which the liquid refrigerant is compressed causes an abnormally high pressure to be generated. Also the inner portion of the compressor encounters a defective lubrication of the bearing portions because the oil supply pump sucks in the liquid refrigerant and thus supplies the coolant to the bearing portions and to the sliding portions. As a result, the mechanisms in the compressor will break and this will result in abrasion and seizing of the sliding portions in the compressor. Now the problems arising from the characteristic of a flow in an accumulator for a refrigeration and air conditioning circuit in which oil for refrigerating machine that is not soluble with the refrigerant will be described. Now another example of the conventional accumulator will be described. Figure 33 is a vertical cross-sectional view showing the structure of an accumulator described in Japanese Patent Publication No. 5-39409. Referring to the drawing, reference numeral 201 represents a container, 202 represents a suction tube, 203 represents a discharge tube and 204 represents liquid refrigerant accumulated in container 201. Reference numeral 205 represents oil for refrigerating machine. The reference numerals 203a to 203e represent plural oil recovery holes open in the vertical direction of the discharge tube 203. In this example, five recovery holes are formed. The reference numeral 203f represents a gas inlet port formed at one end of the discharge tube 203. The U symbol indicates the velocity of a gas in the discharge tube 203. In the refrigeration and air conditioning circuit including the accumulator above, a fluid containing a refrigerant gas, a liquid refrigerant and a refrigerating machine oil is allowed to flow through the suction tube 202, and then is introduced into the container 201. The refrigerant gas and the liquid refrigerant are separated one of the other in interior space within the container 201. Then, the refrigerant gas is allowed to flow from the gas inlet opening 203f to pass through the discharge tube 203, and then discharges to the exterior of the container 201. Moreover, the liquid refrigerant 204 and the refrigerating machine oil 205 accumulate in a lower position of the container 201 if the refrigerating machine oil 205 has little or no No solubility in the liquid refrigerant 204 or if the refrigerating machine oil is in the separation phase of the liquid refrigerant 204 depending on the operating condition, the refrigerating machine oil 205 and the liquid refrigerant 204 in the container 201 are separated one from the another as shown in the drawing. As a result, the oil for cooling machine 205 having a thickness h floats on the liquid refrigerant having the liquid a level of H. The plural oil recovery holes 203a through 203e are formed in the vertical direction, so that the refrigerating machine oil 205 and the liquid refrigerant 204 are sucked into the discharge tube 203 through the oil recovery holes 203a through 203e. Thus, they are mixed with the refrigerant gas and allowed to flow into the apparatus. Now another example of the conventional accumulator will be described. Figure 34 is a vertical cross-sectional view showing the structure of an accumulator described in Exposed Utility Model No. 58-87079. The internal structure of the accumulator is different from that of the conventional apparatus shown in Figure 33. Referring to the drawing, the reference numeral 206 represents a container, 207 represents a suction tube and 208 represents a discharge tube. The reference numeral 208a to 208e represents a plurality of oil recovery holes formed vertically in the discharge tube 208. The reference numeral 209 represents a liquid refrigerant and 210 represents the oil for refrigerating machine. In the refrigeration and air conditioning circuit including the aforementioned accumulator, a fluid containing the refrigerant gas, the liquid refrigerant and a refrigerating machine oil is allowed to pass through the suction tube 207, and is then introduced into the container 206, the refrigerant gas and the liquid refrigerant are separated from each other. Moreover, the refrigerating machine oil 210 and the liquid refrigerant 209 are separated from one another. The refrigerating machine oil 210 having a low specific gravity is brought to a state in which it floats on the liquid refrigerant 209. As the plural oil recovery holes are formed vertically, the refrigerating machine oil 210 and the liquid refrigerant 209 , they are sucked into the discharge tube 208 through the oil recovery holes 208a to 208e. They are then mixed with the refrigerant gas, and allowed to flow into the apparatus. The two conventional structures are similarly operated and suffer from similar problems. The operation and problem of the conventional structure shown in Figure 33 will now be described. The flow rate of the cooling liquid which is introduced into the discharge tube 203 through the recovery holes 203a to 203e is enlarged according to the speed U of the gas flowing in the discharge tube 203 rises and the amount of the liquid refrigerant that accumulates in the container 201, that is, the height H of the liquid refrigerant, is enlarged. Figure 35 shows a characteristic flow rate performed on the assumption that the gas velocity U is a constant value and the thickness h of the oil for cooling machine 205 floating on the liquid refrigerant 204 is constant. Referring to Figure 35, the abscissa axis marks the height H (millimeters) of the liquid refrigerant and the axis of the ordinates marks the flow regime (kilograms / hour) of flow that is introduced into the discharge tube 203. dotted lines indicate the flow rates of portions of the liquid refrigerant that are introduced through the oil recovery holes 203a to 203e. A dotted line that alternates short and long lines that arises from the right indicates the total flow rate of the liquid refrigerant introduced through the respective oil recovery holes. As the H of the liquid refrigerant lengthens, the number of oil recovery holes in the coolant increases. Since the regime of the flows that are introduced through the holes of recovery of inferior oil is enlarging in an amount that corresponds to the potential hydrostatic head of the liquid, the previous flow regime is enlarged in comparison with a regime of the flows which are introduced through the upper oil recovery holes. Therefore, the total flow rate of the liquid refrigerant is not enlarged in proportion to the height H of the liquid refrigerant. The total flow regime increases at an increasing rate. This isAs the level of the liquid refrigerant rises, the quantity of the liquid refrigerant 204 which is sucked into the discharge tube 203 and discharged from the accumulator is enlarged. Now the flow regime of the oil will be described.

A continuous line of saw teeth shown in Figure 35 indicates a flow rate of the oil for cooling machine 205, which floats in the upper portion and which is introduced into the discharge tube 203 through the oil recovery hole. Figure 36 is a diagram showing change in the flow regime of the oil. The amount of oil for refrigerating machine is determined by the refrigeration and air conditioning circuit that includes the accumulator. Since the diameter of each oil recovery hole is usually determined to prevent excessive accumulation of refrigerating machine oil in the accumulator, the amount of refrigerating machine oil that accumulates in the closed container 201 of the accumulator does not change considerably. Therefore, there are one or two oil recovery holes within the thickness h of the refrigerating machine oil, although the number varies depending on the intervals of the oil recovery holes. Figure 36 (a) shows a state in which the oil for cooling machine 205 accumulates in a range including the two oil recovery holes 203c and 203d. Figure 36 (b) shows a state in which the refrigerating machine oil 205 accumulates in a range including an oil recovery hole 203d through the thickness h of the refrigerating machine oil is the same as that of the case shown in (a). That is, the state shown in (a) or that shown in (b) may be performed depending on the change in height H of the liquid refrigerant. As a matter of course, the difference between the two states causes the flow regime to change. Thus, the state shown in (a) is a state in which the oil flow rate is larger than in the state shown in (b). Therefore, even if the thickness h of the refrigerating machine oil is constant, the flow rate of the oil that is introduced into the discharge tube 203 changes somewhat when the height H of the liquid refrigerant is changed. Actually, the flow rate has a tendency towards a saw tooth change, as shown in Figure 35. It is considered an operating condition in which the liquid refrigerant is mixed with the refrigerant gas flowing in the accumulator and the amount of liquid refrigerant in the liquid refrigerant is increased excessively. Moreover, the refrigerating machine oil of the type that is in the separation phase with the liquid refrigerant is used in the accumulator having the conventional structure (see Figures 33 and 34). In the above state, the liquid refrigerant in a large amount is introduced into the compressor because there is a large number of oil recovery holes. In the previous state, the compressor is brought to a state in which the fluid is compressed and thus a high pressure is generated abnormally. Also the inner portion of the compressor encounters a defective lubrication of the support portion because the oil supply pump sucks the liquid refrigerant and thus supplies the liquid refrigerant to the support portions and to the sliding portions. As a result, the moving portions in the compressor encounter abnormal abrasion and seizing. Thus, the refrigeration and air conditioning circuit has a defect in cooling performance or in operation. The prior state sometimes suffers from unsatisfactory reliability as compared to an arrangement in which a soluble machine oil is used with the refrigerant. As can be understood from the description about the conventional apparatus, the flow rate of the liquid refrigerant that is discharged from the accumulator included in the refrigeration and air conditioning circuit is required to be no greater than a certain limit. On the other hand, a somewhat large refrigerant machine oil regime is required to operate the compressor smoothly. The above limits vary in some way depending on the refrigeration and air conditioning circuit that includes the accumulator. To reduce the flow rate of the liquid refrigerant in the conventional structure shown in Figure 33 or 34, it is required that the diameter of each oil recovery hole be reduced, for example. However, the minimum diameter of the oil recovery hole has a limit because a required oil flow rate for the refrigerating machine must be processed. Moreover, the excessive reduction in diameter is not suitable for mass production. What's worse, there is the idea of clogging foreign matter, such as dust, present if the diameter of the hole is too small. Therefore, the diameter must be greater than a certain value, for example, the diameter of the hole should not be smaller than approximately 1.5 mm. However, the previous diameter is too small to reduce the flow rate of the liquid refrigerant. Moreover, another problem arises in the structures shown in Figures 33 and 34 from the point of view of the characteristic flow regime of the oil. That is, if the diameter of each oil recovery hole is made to be a small diameter, the flow rate of the liquid refrigerant should be reduced. In this case, a flow regime required as oil for cooling machine can not be performed. In this case, the oil in large quantity accumulates in the container of the accumulator, causing the amount of oil in the compressor to be reduced. As described above, the conventional accumulator is brought to a state in which the compressor sucks liquid refrigerant in large quantity. Thus, the accumulator is brought to a state in which the liquid refrigerant is compressed, thus causing an abnormally high pressure to be generated. As the supply pump in the compressor sucks the liquid refrigerant and supplies the liquid refrigerant to the support portions and to the moving portions, the support portions suffer from insufficient lubrication. As a result, the mechanism in the compressor can break, abrasion and seizure occur in the moving portion in the compressor. As described above, the conventional accumulator has a problem because the flow rate of both the liquid refrigerant and the refrigerating machine oil can not be properly controlled if the refrigerating machine oil having solubility with the refrigerant or if oil is used is used. for refrigerant machine that has little solubility with the refrigerant. Thus, the reliability of the operation of the compressor has been unsatisfactory. SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to obtain an accumulator that is capable of preventing excessive discharge of the liquid refrigerant from the accumulator, reducing the flow rate of the liquid refrigerant that is introduced into the compressor and reducing the amount of refrigerating machine oil that accumulates in the accumulator so that a required amount of refrigerating machine oil is maintained in the compressor. As a result, it is intended to increase the reliability of the compressor and that of the refrigeration and air conditioning circuit. An accumulator according to a first aspect of the present invention comprises a first space within which a liquid and a gas, which are fluids arranged to circulate • in a refrigeration and air conditioning circuit they are introduced by means of introduction elements; a second space for introducing the gas from the first space by means of a gas passage element, discharging the gas to the cooling circuit and air conditioning by means of discharge elements and having a structure capable of accumulating the liquid; an element that maintains the level of the liquid to prevent the level of the accumulated liquid introduced inside the first space from reaching a level not lower than a previously determined height; the liquid landscape element for moving the liquid from the first space to the second space when the liquid level has been raised to a level not lower than the previously determined height; and a return element opened in the first space in a position lower than the previously determined height and arranged to discharge the accumulated liquid in the first space for the refrigeration and air conditioning circuit. An accumulator according to a second aspect of the present invention has a structure that the liquid passage element and the gas passage element according to the first aspect are formed within a gas passage tube having open ends in a gas portion of the first space and other open ends in the second space and arranged in a vertical direction through the gas portion and a liquid accumulation portion in the first space and the liquid level maintenance element has a communication portion that allows communicating with the gas passage tube disposed in the vertical direction in the first space at the previously determined height, a first passage to establish communication between the communication portion and an upper portion in the first space and a second passage to establish communication between the communication portion and a space in the first space in a position lower than the previously determined height. An accumulator according to a third aspect of the present invention has a structure according to the first or second aspect and arranged to further comprise a movement element for moving the liquid accumulated in the second space towards the first space. An accumulator according to a fourth aspect of the present invention has a structure according to the third aspect and arranged in such a way that the second space is formed above the first space, and the movement element is the communication element for establishing the communication between the portion of liquid accumulation in the second space and the first space. An accumulator according to a fifth aspect of the present invention has a structure according to the third aspect and is arranged in such a way that the movement element establishes the communication between the introduction element and the liquid accumulation portion in the second. space by force of one or a plurality of connecting elements, and an end of the connecting element adjacent to the introduction element is allowed to project on the interior surface of the introduction element towards the interior portion so that the liquid accumulated in the second space the fluid is followed when the fluid is introduced into the first space by the introduction element. An accumulator according to a sixth aspect of the present invention has a structure according to the third aspect and is arranged in such a way that the movement element is composed of a liquid recovery element arranged vertically in the liquid accumulation portion. in the second space and arranged to be able to recover the liquid placed in different positions in a vertical direction and a connecting element to establish the communication between the introduction element and the liquid recovery element, and one end of the connecting element adjacent to the introduction element is allowed to project on the interior surface of the introduction element toward the inner portion, so that the liquid accumulated in the second space is made to follow the fluid when the fluid is introduced into the interior. the first space by the introduction element. An accumulator according to a seventh aspect of the present invention has a structure according to the third aspect and is arranged in such a way that the second space is arranged above the first space, and the movement element is composed of a third space formed in an intermediate position between the second space and the first space, a first open / close valve disposed between the first space and the third space and a second open / close valve disposed between the second space and the third space so that the first open / close valve is closed when the second open / close valve is open and the first open / close valve is open when the second open / close valve is closed in order to move the accumulated liquid in the second space to the first space through the third space. An accumulator according to an eighth aspect of the present invention has a structure according to any of the first to seventh aspects and is arranged in such a way that the liquid level stabilizing element for stabilizing the liquid level in the space is provided either for the first space or for the second space. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing an accumulator according to a first embodiment of the present invention. Figure 2 is a diagram showing the operation of the accumulator according to the first embodiment. Figure 3 is a cross-sectional view showing an accumulator according to a second embodiment of the present invention. Figure 4 is a cross-sectional view showing an accumulator according to a third embodiment of the present invention. Figure 5 is a cross-sectional view showing a first container according to a fourth embodiment.

Figure 6 is a cross-sectional view showing an accumulator according to a fourth embodiment of the present invention. Figure 7 is a cross-sectional view showing an accumulator according to a fifth embodiment of the present invention. Figure 8 is a cross-sectional view showing an accumulator according to a sixth embodiment of the present invention. Figure 9 is a vertical cross-sectional view showing a refrigerant suction tube according to the sixth embodiment. Figure 10 is a cross-sectional view showing the accumulator according to the sixth embodiment. Figure 11 is a cross-sectional view showing an accumulator according to a seventh embodiment of the present invention. Figure 12 is a cross-sectional view showing an accumulator according to an eighth embodiment of the present invention. Figure 13 is a vertical cross-sectional view showing a second container according to the eighth embodiment. Figure 14 is a vertical cross-sectional view showing an accumulator according to a ninth embodiment of the present invention. Figure 15 is a vertical cross-sectional view showing an accumulator according to a tenth embodiment of the present invention. Figure 16 is a diagram showing the operation of a movement element according to the tenth embodiment of the present invention. Figure 17 is a vertical cross-sectional view showing an accumulator according to an eleventh embodiment of the present invention. Figure 18 is a vertical cross-sectional view showing an accumulator according to a twelfth embodiment of the present invention. Figure 19 is a vertical cross-sectional view showing an accumulator according to a thirteenth embodiment of the present invention. Figure 20 is a vertical cross-sectional view showing an accumulator according to a fourteenth embodiment of the present invention. Figure 21 is a vertical cross-sectional view showing an accumulator according to a fifteenth embodiment of the present invention. Figure 22 is a cross-sectional view showing an accumulator according to a sixteenth embodiment of the present invention.

Figure 23 is a cross-sectional view showing an accumulator according to a seventeenth embodiment of the present invention. Figure 24 is a cross-sectional view showing an accumulator according to a eighteenth embodiment of the present invention. Figure 25 is a cross-sectional view showing an accumulator according to a nineteenth embodiment of the present invention. Figure 26 is a cross-sectional view showing an accumulator according to a twentieth embodiment of the present invention. Figure 27 is a vertical cross-sectional view showing a gas communication tube according to the twentieth embodiment. Figure 28 is a cross-sectional view showing an accumulator according to a twenty-first embodiment of the present invention. Figure 29 is a cross-sectional view showing an accumulator according to a twenty-second embodiment of the present invention. Figure 30 is a cross-sectional view showing an accumulator according to a twenty-third embodiment of the present invention. Figure 31 is a vertical cross-sectional view showing an example of a conventional accumulator. Figure 32 is a graph showing the flow rates (kg / h) of liquid refrigerant and oil for refrigerating machine with respect to the height (mm) of the level of the liquid refrigerant in the conventional accumulator. Figure 33 is a vertical cross-sectional view showing another example of a conventional accumulator. Figure 34 is a vertical cross-sectional view showing another example of a conventional accumulator. Figure 35 is a graph showing flow rates (kg / h) of the liquid refrigerant and the refrigerating machine oil with respect to the height (mm) of the level of the liquid refrigerant in the conventional accumulator. Figure 36 is a graph showing a change in the flow regime in the conventional accumulator.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES First Mode The structure of an accumulator for use in a refrigeration and air conditioning circuit according to a first embodiment of the present invention is now described. Figure 1 is a diagram showing an accumulator having a structure in which a first container is disposed below a second container. Figure 1 (a) is a vertical cross-sectional view and Figure 1 (b) is a cross-sectional view taken along the line X-X shown in Figure 1 (a). In this embodiment, it is assumed that oil is used for a refrigerating machine that has poor solubility with the refrigerant for use in the refrigeration and air conditioning circuit. Referring to the drawings, the reference numeral 1 represents a first space that is a first container and 2 represents a second space that is a second container. Reference numeral 3 represents an introduction element which is, for example, a suction tube, for introducing refrigerant gas, liquid refrigerant and oil for cooling machine circulating in the refrigeration and air conditioning circuit. Reference numeral 4 represents a tube, which is a gas passage tube, which serves as both a liquid passage element and a gas passage element. Although the gas passage tube 4 has a primary function of introducing the refrigerant gas into the first container 1 within the second container 2, this embodiment has a structure in which also the liquid refrigerant and the oil for the refrigerating machine are allowed to pass to through the gas passage tube 4 so that they move to the second container 2. The reference numeral 5 represents a discharge element for discharging the refrigerant gas to the refrigeration and air conditioning circuit, the discharge tube being a discharge tube . The reference numeral 6 represents a return element for moving the refrigerating machine oil accumulated in the first container to the cooling and air conditioning circuit, the return element being an oil return tube. Reference numeral 7 represents refrigerant gas. The gas passage tube 4 has one end that is open in a gas portion in the first container 1 and another open end in the second container 2. The gas passage tube 4 is, in the first container 1, arranged vertically through the gas portion and the liquid accumulation portion. The gas passage tube 4 is allowed to communicate with the communication tube 8 at a predetermined height from the bottom of the first container 1 in which the level of the liquid is required to be maintained. The communication tube 8 is connected to the air duct tube 7. Thus, an upper end 7a of the air duct tube 7 from the position in which the communication tube 8 is connected forms a first passage which establishes the communication between the communication tube 8 and an upper portion in the first container 1. A lower end 7b of the air duct tube 7 from the position in which the communication tube 8 is connected forms a second passage that establishes the communication between the communication tube 8 and an upper portion in the first container 1 that is lower than a predetermined height. Now the operation of the accumulator having the structure mentioned above will be described. The refrigerant gas 9 discharged from an evaporator in the refrigeration and air conditioning circuit is introduced from the suction tube 3 into the first container 1. Then, the refrigerant gas 9 is allowed to pass through the gas passage tube 4, and then it is introduced into the second container 2, after which the refrigerant gas 9 is introduced into the compressor. At this time, the operating condition of the refrigeration and air conditioning circuit results in the liquid refrigerant and the refrigerating machine oil 11 being mixed with the refrigerant gas 9. The refrigerant gas 9, the liquid refrigerant 10 and the oil for refrigerating machine 11 introduced into the first container 1 are subjected to gas and liquid separation. Thus, the liquid refrigerant 10 and the oil for refrigerating machine 11 separated from each other, accumulate in the bottom portion of the first container 1. Assuming that the liquid refrigerant 10 and the oil for refrigerating machine 11 do not have mutual solubility and that employs the refrigerant machine oil 11 having a specific density lower than that of the liquid refrigerant 10, the refrigerating machine oil floats on the upper surface of the liquid refrigerant 10. The oil return tube 6 is connected to a separate return circuit the oil for refrigerating machine 11 to the compressor. The arrows shown in the drawing indicate flows of the refrigerant gas 9 (arrows of thin hollow lines), the liquid refrigerant 10 (dotted arrows) and oil for refrigerating machine 11 (arrows in diagonal line). The operation of the air duct tube 7 will be described later with reference to Figure 2. The main function of the air duct tube 7 is a function to maintain a predetermined height of the liquid level (the height of the liquid level) in the first container l. When oil is used for refrigerating machine which has poor solubility with the refrigerant, the air duct tube 7 has a function to selectively move the liquid refrigerant 10 to the second container 2. That is, the liquid refrigerant 10 is introduced from the tube of liquid. communication 8 inside the gas passage tube 4 so as to be brought to a multi-phase flow state with the refrigerant gas 9 and introduced from the first container 1 into the second container 2. Since the effect of gas separation liquid can be obtained in the second container 2, the refrigerating machine oil is accumulated in the bottom portion of the second container 2, after which the refrigerant gas is collected. Only the refrigerant gas 9 is discharged from the discharge tube 5 to the compressor. As the height of the liquid in the first container 1 is substantially constant as described above, the influence of the height of the liquid in the discharge flow rate is not exerted, as was experienced with the conventional accumulator. Thus, the flow regime can be stabilized. In addition, the refrigerant machine oil 11 flowing above the liquid refrigerant 10 can be selectively discharged from the oil return tube 6. The operation of the air duct tube 7 will now be described. Figures 2 (a), 2 (b) ) and 2 (c) are diagrams showing the operation in the first container 1. Referring to the drawings, hl indicates the height from the bottom surface of the first container 1 to the oil return pipe 6, and h2 indicates the height from the bottom surface of the first container 1 to the communication tube 8. The heights satisfy hl <; h2. The lower end 7b of the air duct tube 7 is opened in a position lower than the height of the oil return pipe 6. Assuming that the height from the bottom surface of the first container 1 to the lower end 7b of the duct pipe air 7 is h3, the ratio h3 < hl is satisfied.

Note that the upper end 7a of the air duct tube 7 is open to substantially the same position as that of the upper end of the gas passage tube 4. Figures 2 (a) and 2 (b) show a state in which the liquid refrigerant 10, together with the refrigerant gas 9, is introduced from the evaporator into the accumulator. Figure 2 (a) shows a state in which the height of the liquid level (the oil level) is not greater than h2. Figure 2 (c) shows a state of operation of the refrigeration and air conditioning circuit in which the liquid refrigerant 10 is not introduced from the evaporator into the accumulator and only the refrigerant gas 9 and the refrigerating machine oil 11 are introduced. inside the accumulator. Referring to Figure 2, the function of maintaining a substantially constant height of the liquid level (the oil level) in the first container 1 and a function of selectively introducing only the liquid refrigerant 10 from the gas passage tube 4 within of the second container 2 will now be described. Figure 2 (a) shows a state in which the liquid refrigerant 10 and the oil for cooling machine 11 were accumulated in the first container 1. As the oil for refrigerating machine 11 has a smaller specific density, the oil for refrigerating machine 11 floats on the liquid refrigerant 10. The oil return pipe 6 has a diameter and a length that allows the refrigerating machine oil that was introduced into the first container 1, to be discharged. Moreover, the diameter and length of each of the end 7b and the communication tube 8 are determined to be capable of discharging the liquid refrigerant in an amount that is introduced into the first container 1. If the height of the liquid level (the level of the oil) is not less than h2 as shown in Figure 2 (a), the height of the liquid in the first container 1 and that of the tube of the air duct 7 is made to be of the same level. Therefore, the communication tube 8 is filled with the liquid refrigerant 10. As a result, the liquid refrigerant 10 is allowed to flow from the lower end 7b of the tube of the air conduit 7 through the communication tube 8, and then inserted into the second container 2. As the position of the lower end 7b of the tube of the air duct 7 is included in the layer of the liquid refrigerant 10, only the liquid refrigerant 10 is introduced from the lower end 7b of the tube of the air duct 7 below the height of the liquid level (the oil level). When the amount of the liquid refrigerant introduced from the suction tube 3 is reduced and the height of the liquid level (the level of the oil) in the first container 1 is not higher than h2, the state shown in Figure 2 is realized ( b) Thus, the refrigerant gas 9 flows from the upper end 7a of the tube of the air duct 7 to the communication tube 8. Therefore, the liquid refrigerant 10 is not introduced from the lower end 7b of the tube of the air duct 7. therefore, when the liquid refrigerant 10 is introduced from the suction tube 3 in the aforementioned state, the height of the liquid level (the level of the oil) rises. Thus, the state shown in Figure 2 (a) is performed. That is, the effect can be obtained because the substantially constant height of the liquid level (the oil level) in the first container 1 can be maintained close to the position (the height h2 from the bottom surface) to which it is available the communication tube 8. A state in which no liquid refrigerant is introduced into the accumulator is frequently performed as the operating state of the refrigeration and air conditioning circuit. The state in which the liquid refrigerant 10 is not introduced from the suction tube 3 and the refrigerant gas 9 and the refrigerating machine oil 11 are introduced., is shown in Figure 2 (c). The dimensions of the oil return pipe 6 are determined in such a way that a maximum amount of oil that was introduced from the suction pipe 3 can be discharged. Moreover, the design is performed in such a way that the oil level for machine Refrigerant 11 does not exceed h2 as shown in Figure 2 (c). Therefore, the refrigerating machine oil 11 is not introduced from the lower end 7b into the second container 2 through the communication tube 8. Therefore, the discharge of the refrigerating machine oil 11 to the second container 2 can be prevented. As a result of sequential operations, the substantially constant height of the liquid level (the level of the oil) in the first container 1 can be maintained. Although a mixed fluid of refrigerating machine oil 11 or the liquid refrigerant and refrigerating machine oil is discharged from the oil return pipe 6 to the compressor, the flow rate from the oil return pipe 6 to the compressor becomes be constant because the height of the liquid in the first container 1 is substantially constant. That is, the phenomenon that the height of the liquid level in the container rises and thus the flow rate of the liquid refrigerant that is returned to the compressor is enlarged does not occur as has been experienced with the conventional apparatus. When the flow rate from the oil return tube 6 1 compressor is made not to be as great as the limit of introduction of the liquid refrigerant to the compressor, the flow rate of the liquid refrigerant that is introduced into the communication can be avoid. Thus, it can avoid any defect of the compressor. As described above, the structure of the accumulator according to this embodiment is arranged as described above for use in the refrigeration and air conditioning circuit in which the refrigerating machine oil is used which does not dissolve in the liquid refrigerant. Thus, the refrigerating machine oil of the liquids that accumulate in the first container 1 can be returned to the compressor and an excessive amount of the liquid refrigerant exceeding a predetermined height can be selectively moved to the second container 2 to be accumulated. Therefore, the refrigerating machine oil can efficiently circulate and a required amount of refrigerating machine oil can be maintained in the compressor. As the second container 2 has the gas-liquid separation function, only a small amount of liquid refrigerant is discharged from the discharge pipe 5 to the refrigeration and air conditioning circuit. Second Mode The structure of an accumulator for use in a refrigeration and air conditioning circuit according to a second embodiment of the present invention will now be described. The second mode has the same function as that of the first mode, except that the refrigerating machine oil has little solubility with the refrigerant used in the refrigeration and air conditioning circuit. In this embodiment, the first container is disposed above the second container to cause the liquid refrigerant in the first container to be deposited so that the liquid refrigerant accumulates in the second container. Figure 3 is a diagram showing the accumulator according to this embodiment having a structure that the first container 1 is disposed above the second container 2. Figure 3 (a) is a vertical cross-sectional view, and the Figure 3 (b) is a cross-sectional view taken along the line XX shown in Figure 3 (a). Referring to the drawings, the reference numeral 12 represents a gas communication tube arranged to establish the connection between the first container 1 and the second container 2 and structured to allow a flow of the refrigerant gas 9. The reference numeral 12ci represents an outlet opening of the gas communication tube, and 12b represents an inlet opening of the gas communication tube. The reference numeral 13 represents an air duct tube disposed in parallel to the gas communication tube 12 and formed within a tube figure having two open vertical ends. The reference numeral 13a represents an upper end 13a of the pipe of the air duct 13. The reference numeral 13b represents a lower end 13b of the pipe of the air duct 13. A position near an intermediate position of the pipe of the air duct 13 is connected to the lateral surface of the gas communication tube 12 through a communication tube 14. The structure with which the tube of the air duct 13 and the gas communication tube 12 are connected with each other is the same as according to the first modality. The height hl from the bottom surface of the first container 1 to the oil return pipe 6, the height h2 from the bottom surface of the first container 1 to the communication pipe 14 and the height h3 from the bottom surface of the first container 1 until the lower end 13b of the pipe of the air duct 13 satisfies h3 <; hl < h2. The upper end 13a of the tube of the air duct 13 opens in substantially the same position as that of the upper end of the gas communication tube 12. As a result of the structure mentioned above, the gas communication tube 12, the tube of the air duct 13 and communication tube 14 have the function described with reference to Figure 2. Thus, an effect can be obtained because the substantially constant height of the liquid level (the level of the oil) can be maintained in the first container 1. That is, when the height of the liquid level (the oil level) in the first container 1 is not greater than h2, the refrigerant gas 9 is introduced into the gas communication tube 12, the air duct tube 13 and the communication tube 14. When the height of the liquid level (the oil level) is not less than hl, the refrigerating machine oil that floats in the upper portion between the liquid accumulates The first container 1 is discharged from the oil return tube 6. When the height of the liquid level (the level of the oil) in the first container 1 is made to be no less than h2, the liquid refrigerant 10 is introduced. from the lower end 13b of the tube of the air duct 13 inside the gas communication tube 12. The liquid refrigerant 10, attributable to the drop in density and gas flow, moves to the second container 2 arranged in the lower position , and then accumulates in the bottom portion of the second container 2. Thus, similarly to the first embodiment, the accumulator for the refrigeration and air conditioning circuit in which the machine oil is used which has little solubility with the Liquid refrigerant is capable of selectively returning refrigerant machine oil 11 from the oil return pipe 6 to the compressor. Moreover, the liquid refrigerant 10 can selectively accumulate in the second container 2. As the second container 2 has the function of gas-liquid separation, the discharge of the liquid refrigerant from the discharge tube 5 does not enlarge considerably even if the liquid refrigerant accumulate in the second container 2.

As described above, this embodiment is also capable of making the height of the liquid level in the first container 1 substantially the constant height of h2. Therefore, the flow rate from the oil return pipe 6 to the compressor can be made constant. Thus, the phenomenon experienced with the conventional apparatus can be avoided in that the flow rate of the liquid refrigerant returning to the compressor is enlarged to the height of the liquid level in the container. Although the oil for refrigerating machine or a mixed fluid of oil for refrigerating machine and the refrigerant is discharged from the oil return pipe 6, the adjustment of the inner diameter of the oil return pipe 6, or the like allows the flow rate from the oil return pipe 6 to the compressor is no larger than the limited amount of introduction of the liquid refrigerant to the compressor. As a result, a required amount of refrigerating machine oil can be maintained in the compressor. Thus, the occurrence of a compressor defect can be avoided. Third Mode In the first and second embodiments, accumulators have been described that have been arranged to be adaptable to the refrigeration and air conditioning circuit which uses refrigerating machine oil that has poor solubility with the refrigerant. An accumulator according to this embodiment is applied to a refrigeration and air conditioning circuit that uses oil for refrigerating machine that has solubility with the refrigerant. The first and second embodiments are arranged on the assumption that the refrigerating machine oil having low solubility with the refrigerant has the structure that the inner portion of the first container 1 is provided with an element for separating the liquid refrigerant and the refrigerating machine oil one of another and the element to make the height of the liquid refrigerant and the oil for refrigerating machine constant. On the other hand, the third embodiment is provided on the assumption that the refrigerating machine oil having solubility with the refrigerant is used in the refrigeration and air conditioning circuit. Thus, an object of this embodiment is to perform a function to make the height of the liquid refrigerant (including the refrigerating machine oil) in the first container 1 constant. Moreover, the limitation of the liquid refrigerant (including the refrigerating machine oil) that is discharged from the accumulator to the compressor is attempted. The accumulator will now be described for use in the refrigeration and air conditioning circuit according to the third embodiment of the present invention. Figure 4 is a diagram showing the structure of the accumulator according to this embodiment and having a structure in which the first container 1 is disposed above the second container 2, similar to the second embodiment. Figure 4 (a) is a vertical cross-sectional view, and Figure 4 (b) is a cross-sectional view taken along the X-X line shown in Figure 4 (a). Referring to the drawings, the reference numeral 15 represents a gas communication tube that establishes the communication between the first container 1 and the second container 2. The reference numeral 15a represents a communication hole and 15b represents an upper end of the communication tube 15. The reference numeral 15b represents an upper end of the gas communication tube 15. The reference numeral 15c represents a lower end of the gas communication tube 15. The reference numeral 16a represents a liquid refrigerant in wherein the refrigerating machine oil that accumulates in the first container 1 dissolves, and 16b represents a liquid refrigerant in which the refrigerating machine oil that accumulates in the second container 2 is dissolved. The upper end 15b of the refrigerant pipe gas communication is disposed above the first container 1, while the lower end 15c of the communication tube Gas ion is disposed above the second container 2. The height h4 of the communication hole 15a is a previously determined height at which it is required to maintain the liquid level, the height h4 being higher than the position hl of the return pipe of oil 6. That is, hl <; h4 is satisfied. Now the operation will be described. Figure 4 (a) shows a state of operation in which the liquid refrigerant (in which the oil for refrigerating machine is dissolved) 16 is introduced from the suction tube 3. As the liquid refrigerant (in which the oil for refrigerating machine dissolves) 16 is subjected to the gas-liquid separation in the first container 1, the liquid refrigerant 16 accumulates in the first container 1. When the liquid refrigerant (in which the oil for refrigerating machine dissolves) accumulated 16a in the first container l exceeds the height of the communication hole 15a, is allowed to pass through the communication hole 15a and moves to the second container 2. Therefore, the height of the refrigerant (in which the oil for refrigerating machine is dissolves) the first and the second * a of the liquid refrigerant (in which the refrigerating machine oil dissolves) 16a in the first container 1 does not exceed the height h4 of the communication hole 15a . As a result, the height of the liquid refrigerant in the first container 1 of the boundary and the flow rate of the liquid refrigerant (in which the refrigerating machine oil dissolves) that is discharged from the oil return pipe 6 to the compressor is made that is substantially constant. A state in which the liquid refrigerant is not introduced from the suction tube 3 and only the oil for refrigerating machine is introduced can be carried out according to the operating state. Also in this case, the structure of the oil return pipe 6 is arranged in such a way that it allows the refrigerating machine oil in a quantity that is introduced from the suction pipe 3 to discharge in a manner similar to the first and second modes. . Thus, the height does not exceed the height of the communication hole 15a. Therefore, the discharge of oil for refrigerating machine 11 to the second container 2 can be prevented. Thus, the state in which the oil for refrigerating machine is accumulated is not realized. If the amount of liquid refrigerant accumulated in the accumulator shown in Figure 31 is enlarged in the conventional apparatus, the flow rate of the liquid refrigerant, which is discharged to the compressor is increased. However, this mode is capable of making the flow rate constant regardless of the amount of refrigerant accumulated. Even if no liquid refrigerant is introduced into the accumulator and refrigerating machine oil is introduced, the refrigerating machine oil can be recovered reliably from the accumulator to the compressor, a defect of the compressor operation can be avoided. Figure 5 shows an example in which the shape and position of the gas communication tube 15 shown in Figure 4 (a) are changed. In this case too, a similar effect can be obtained. Referring to Figure 5, the reference numeral 15d represents a gas communication tube that has no communication hole. The upper end of the gas communication tube 15d corresponds to the height of the communication hole 15a shown in Figure 4 (a), the upper end being made to be in a position at which a constant level of liquid can be made, that is, a somewhat higher position than the oil return pipe 6. As a result of an operation similar to that shown in Figure 4 (a), the height of the liquid level in the first container 1 can be limited . As a result, the flow rate of the liquid refrigerant (in which the refrigerating machine oil dissolves) which is discharged from the oil return tube 6 to the compressor can be made to be substantially constant. Although this embodiment has the structure in which the first container 1 is disposed above the second container 2, the first container 1 can be disposed below the second container 2 to obtain a similar effect, as can be easily understood from the first modality. Fourth Mode An accumulator for use in a refrigeration and air conditioning circuit according to a fourth embodiment of the present invention will now be described. Also the accumulator according to this embodiment has the elements for separating the liquid refrigerant and the refrigerating machine oil from one another and the element for making the heights of the liquid refrigerant and the refrigerating machine oil constant. In this embodiment, the structure for making the level in the first container constant is formed in such a way that a communication hole is formed in the lateral surface of the communication tube. Moreover, a tube having a diameter greater than that of the gas communication tube is arranged * to include the gas communication tube. Figure 6 (a) is a vertical cross-sectional view showing the accumulator according to this embodiment. Figure 6 (b) is a cross-sectional view of Figure 6 (a). Referring to the drawings, the reference numeral 17 represents a cylinder arranged in such a way that the cylinder 17 includes the gas communication tube 15. The reference numeral 17a represents a lower end of the cylinder 17, the lower end 17a being a passage through which the liquid refrigerant flows. The reference numeral 17b represents an upper end of the cylinder 17, the upper end 17b being a passage through which the cooling gas flows. The reference numeral 18 represents a gap between the gas communication tube 15 and the cylinder 17. In order to maintain an appropriate gap c between the lower end 17a of the cylinder 17 and the bottom surface of the first container 1, the elements they are secured to the first container 1. The gas communication tube 15 has a communication hole 15a formed in a predetermined position in which it is required to maintain the level of the liquid. Now the operation of the accumulator according to this embodiment will be described, in such a way that a comparison is made with the modality shown in Figure 1. The gap 18 corresponds to the tube of the air duct 7, while the hole 15a corresponds to the tube 8. Therefore, when the level of the liquid (the oil level) in the first container 1 is higher than h2, the liquid refrigerant is allowed to pass through the lower end 17a of the cylinder 17, and is introduced into the of the cooling liquid 16 through the communication hole 15a, after which the liquid refrigerant is discharged to the second container 2. When the level of the liquid (the level of the liquid) in the first container 1 is less than h2, the refrigerant gas 9 is allowed to pass through the gap 18, and then is introduced into the gas communication tube 15 through the communication hole 15a. As a result, the liquid refrigerant is not introduced into the gas communication tube 15. As described above, the liquid refrigerant 16 and the cylinder 17 form the element to make the heights of the liquid refrigerant and the refrigerating machine oil constant. . The element for separating the liquid refrigerant and the refrigerating machine oil from one another can be arranged in such a way that the first container 1 is kept calm and the oil return pipe 6 is arranged in the position in the oil layer for refrigerating machine separated from the liquid refrigerant due to the characteristic of the refrigerating machine oil. As described above, the fourth mode is capable of performing the same function that can be performed by the first and second modes. The fourth mode is structured on the assumption that oil is used for a refrigerating machine that has poor solubility with the refrigerant. The difference of the third mode is that the cylinder 17 is provided. Therefore,, if the structure of this embodiment is applied to the refrigeration and air conditioning circuit using oil for refrigerating machine having solubility with the refrigerant, the level of the liquid in the first container 1 can be made to be constant in a similar way to the structure in which the oil for refrigerating machine has no solubility or has little solubility. Fifth Mode The accumulator will now be described for use in the refrigeration and air conditioning circuit according to the fifth embodiment of the present invention. Also the accumulator according to this embodiment is structured to be adaptable to a box in which the refrigerating machine oil is used which has little solubility with the refrigerant in the refrigeration and air conditioning circuit. The first container 1 is provided with the element for separating the liquid refrigerant and the refrigerating machine oil and the element for making the heights of the liquid refrigerant and the refrigerating machine oil consistent. In this embodiment, the level of the liquid in the first container is made to be constant by diagonally cutting the lower end portion of the gas communication tube and a tube having a diameter larger than that of the gas communication tube is arranged for Include the gas communication tube. Figure 7 (a) is a vertical cross-sectional view showing the accumulator according to this embodiment. Figure 7 (b) is a cross-sectional view taken along the line X-X shown in Figure 7 (a). The reference numeral 19 represents the gas communication tube having a lower end 19a cut diagonally. As shown in the drawings, the gas communication tube 19 is secured in such a way that a larger or smaller gap is formed between the lower end 19a and the bottom surface of the first container 1. The position is a position in the which maintains the level of liquid required. The reference numeral 20 represents a cylinder arranged to include the gas communication tube 19. The reference numeral 20a represents a lower end of the cylinder 20, and 20b represents an upper end thereof. The reference numeral 21 represents a gap between the gas communication tube 19 and the cylinder 20, the gap 21 having upper and lower ends. The height of the lower end 20a is lower than the lower end 19a of the gas communication tube 19, while the height of the oil return pipe 6 is included in a range between the lower end 19a of the communication tube 1 and the lower end 20a of the cylinder 20. The operation will now be described. Figure 7 (a) shows a state in which the refrigerating machine oil 11 and the liquid refrigerant 10 exist in the first container 1. The liquid refrigerant 10 is allowed to pass through the gap between the lower end 20a of the cylinder 20 and the bottom surface of the first container 1, and then it is introduced into the gap 21. Then, the liquid refrigerant 10 reaches the lower end 19a of the gas communication tube 19. The lower end 19a cut diagonally has an adjacent lower end to liquid refrigerant 10 as illustrated. As the refrigerant gas 9 flows adjacent the surface of the liquid refrigerant 10 when the refrigerant gas is introduced into the lower end 19a of the gas communication tube 19, a portion of the liquid refrigerant 10 is moved upwardly. Thus, the liquid refrigerant 10 is discharged from the first container 1, and then accumulated in the second container (not shown). When the liquid level of the liquid refrigerant 10 has been raised further, the area of the lower end 19a of the gas communication tube 19 through which the refrigerant gas is allowed to pass is reduced. Thus, the flow rate rises, causing the liquid refrigerant 10 to move upward by a larger amount. If the liquid level of the liquid refrigerant 10 is low, the amount of discharge from the first container 1 is reduced. As a result, the level of the liquid in the first container 1 can be made to be constant. The fifth embodiment has the structure to be adaptable to use oil for refrigerating machine that has little solubility with the refrigerant. Another structure can be used from which the cylinder 20 is omitted to obtain an effect similar to that obtainable from the fourth embodiment in the case that refrigerating machine oil having solubility with the refrigerant is used in the refrigeration and air conditioning circuit. Sixth Mode An accumulator will now be described for use in a refrigeration and air conditioning circuit according to a sixth embodiment of the present invention. Also, the accumulator according to this embodiment is structured to be adaptable to the refrigeration and air conditioning circuit using oil. for refrigerant machine that has little solubility with the refrigerant. The first container includes the elements for separating the liquid refrigerant and the refrigerating machine oil from one another and the element for making the heights of the liquid refrigerant and the refrigerating machine oil constant. In this embodiment, the level of the liquid in the first container is made constant by a structure in which the first container is disposed above or below the second container. Moreover, the first container and the second container are connected to each other by a liquid return tube, and a cylinder (a tube) having a larger diameter than the liquid return tube is arranged in such a way that it includes the portion near the upper portion of the liquid return tube. Figure 8 (a) is a vertical cross-sectional view showing an accumulator according to this embodiment, and Figure 8 (b) is a cross-sectional view taken along the line XX shown in Figure 8 ( to) . In this embodiment, the first container 1 is disposed below the second container 2. Referring to the drawings, the reference numeral 22 represents a gas communication tube for establishing communication between the first container 1 and the second container 2 of so that the upper space in the first container 1 and the upper space in the second container 2 allow one to communicate with the other. The reference numeral 23 represents a cylinder, 23a represents a lower end of the cylinder 23, and 23b represents an upper end 23b of the cylinder 23 .. The lower end 23a of the cylinder 23 is secured in such a way that an appropriate gap is formed from the portion of the bottom of the first container 1. The reference numeral 24 represents a refrigerant suction tube that establishes the communication between the bottom portion of the second container 2 and the first container 1. Reference numeral 24a represents a lower end of the tube refrigerant suction 24. The reference numeral 24b represents an upper end of the refrigerant tube 24. The upper end 24b of the refrigerant suction tube 24 is disposed in the bottom portion of the second container 2, while the position of the lower end 24a of the refrigerant suction pipe is superior to the oil return pipe 6. That is, the position of the lower end 24a of the The suction tube of the refrigerant is made to be at the height at which the liquid is required to be maintained. Moreover, the upper end 23b of the cylinder 23 is made to be superior to the lower end 24a of the refrigerant suction pipe 24, while the lower end 23a of the cylinder 23 is made to be inferior to the oil return pipe 6. Now the operation will be described. Figure 8 (a) shows a state in which the refrigerating machine oil 11 and the liquid refrigerant 10 exist in the first container 1. When the refrigerant gas 9 flows from the first container 1 into the second container 2 through the tube gas communication 22, a loss of pressure (pressure difference? P) takes place. That is, the pressure in the first container 1 is made to be higher than the pressure in the second container 2 by? P. Therefore, the liquid refrigerant 10 in the first container l is allowed to pass through the cylinder 23 and the refrigerant suction pipe 24, and then pushed up into the second container 2. The cylinder 23 has a similar function to the cylinder 17 according to the fourth embodiment. By Thus, only the liquid refrigerant 10 is selectively allowed to pass through the gap formed by the lower end 23a of the cylinder 23, and is then introduced into the second container 2. When the refrigerant gas 9 is not introduced from the suction tube 3 in an interruption box of the operation of the refrigeration and air conditioning circuit, the pressure difference is not generated. Therefore, the liquid refrigerant 10 and the oil for refrigerating machine 11 accumulated in the second container 2 is allowed to pass through the refrigerant suction tube 24, and then dropped into the first container 1. Figure 9 shows a state in which the position of the upper end of the suction tube of refrigerant is different from the one in the box shown in 1 Figure 8 (a).

Referring to the drawing, the reference numeral 25 represents a refrigerant suction tube having an upper end 25a that is open in the space within the second container 2. As the pressure difference P is also generated in the structure shown in FIG. Figure 9 similar to the structure shown in Figure 8 (a), only the liquid refrigerant 10 is selectively introduced into the second container 2 so that the liquid refrigerant moves to the second container 2 regardless of the position of the upper end of the refrigerant suction tube 25. The difference in structure of that shown in Figure 8 (a) rests on the height of the upper end 25a of the refrigerant suction tube 25. Therefore, the difference in function rests on the that the liquid refrigerant 10 and the refrigerating machine oil 11 accumulated in the second container 2 does not fall into the first container l even if the refrigerant gas ante 9 is not introduced from the suction tube 3 (when the operation of the apparatus is interrupted). As described above, this embodiment is apt to cause the liquid level in the first container 1 to be substantially constant. Therefore, the oil for cooling machine 11 can be made to exist adjacent the height of the oil return pipe 6 and thus the oil for cooling machine 11 can be selectively returned to the compressor. Moreover, the liquid refrigerant 10 can be accumulated in the second container 2. A modification of this mode will now be described. Figure 10 (a) is a vertical cross-sectional view showing an accumulator according to this modification. Figure 10 (b) is a cross-sectional view taken along the line X-X shown in Figure 10 (a). As shown in Figure 10, the modification is structured in such a way that the first container 1 is disposed above the second container 2. Referring to the drawings, the reference numeral 26 represents a gas communication tube for establishing the communication between the first container l and the second container 2. Thus, the upper space in the first container 1 and the upper space in the second container 2 are allowed to communicate with each other. The reference numeral 27 represents a cylinder and 27b represents a lower end of the cylinder 27. The reference numeral 27a represents an upper end of the cylinder 27. The lower end 27b of the cylinder 27 is secured in such a way that an appropriate gap is formed from the bottom portion of the first container 1. Reference numeral 28 represents a refrigerant return pipe and 28a represents an upper end of the refrigerant return pipe 28. Reference numeral 28b represents a lower end of the refrigerant return pipe 28. When the structure is arranged in such a way that the position of the lower end 27b of the cylinder 27 < the position of the oil return tube 6 < the position of the end 28a of the refrigerant return pipe 28, the level of the liquid can be made to be constant in a position near the upper end 28a of the return pipe of the refrigerant 28 in a manner similar to the structure shown in Figure 8. Even if the liquid refrigerant 10 and the oil for refrigerating machine 11 accumulate in the first container 1, only the liquid refrigerant can be selectively discharged to the second container 2. This embodiment has the structure in which the refrigerating machine oil is used which has little solubility with the refrigerant in the refrigeration and air conditioning circuit, a structure from which the cylinder 23 (shown in Figures 8 and 9) is omitted to obtain a similar effect. Seventh Mode An accumulator according to a seventh embodiment and adaptable to a refrigeration and air conditioning circuit is described at this time. This embodiment has a structure in which the level of the liquid (the oil level) in the first container is made constant by a floating structure comprising a liquid return hole formed in the side surface of a gas communication tube. and the liquid return hole opens or closes in synchronization with the liquid level in the first container. Figure 11 is a vertical cross-sectional view showing the accumulator according to this embodiment. Referring to the drawing, the reference numeral 29 represents a gas communication tube for establishing communication between the upper space in the first container 1 and the upper space in the second container (not shown). The reference numeral 29a represents a coolant return hole formed in the side surface of the gas communication pipe 29. The coolant return hole 29a is formed in a position lower than the position of the oil return pipe 6. reference numeral 30 represents a float made by resin or metal molding having spaces for batch on the liquid refrigerant 10 and the oil for cooling machine 11. That is, the float 30 can be made of a material having a specific density which is less than the specific density of the oil for refrigerating machine 11 because the specific density of the oil for refrigerating machine 11 is about 0.9. The float 30 floats on the liquid refrigerant 10 and the oil for the refrigerating machine 11 in the first container 1 and moves according to the level of the liquid. When, for example, only the refrigerating machine oil 11 mixed with the refrigerant gas 9 is introduced into the first container 1, the liquid level is low, as shown in Figure 11 (a). Thus, the return hole of the refrigerant 29 (a) is closed. Therefore, even if the refrigerating machine oil 11 accumulates on the return hole of the refrigerant 29a, the refrigerating machine oil 11 is not introduced into the gas communication tube 29. When the refrigerating machine oil 11 and the liquid refrigerant 10 mixed with the refrigerant gas 9 are introduced into the first container 1 as shown in Figure 11 (b), the existing refrigerant machine oil 11 and the liquid refrigerant 10 are separated from each other in the first container 1. In this case, the level of the liquid in the first container is made to be higher than that made in the structure shown in Figure 11 (a). As a result, the return hole of the refrigerant 29a is open. Therefore, the liquid refrigerant 10 accumulated on the return hole of the refrigerant 29a is introduced into the gas communication tube 29. As a result of the aforementioned operation, the liquid refrigerant 10 moves selectively to the second container so that the liquid refrigerant 10 is returned from the oil return pipe 6 to the compressor. The seventh embodiment is arranged to make the level of the liquid in the first container 1 constant and only the liquid refrigerant selectively moves to the second container. The liquid refrigerant and the refrigerating machine oil are naturally separated from one another if the first container 1 is kept calm. However, an actual operating state is sometimes in a state in which the liquid refrigerant and the refrigerating machine oil are not separated from each other satisfactorily. In this case, the refrigerant machine oil is sometimes introduced into the second container although the flow rate is small. In an example case in which the refrigeration and air conditioning circuit is operated for a prolonged period of time, the refrigerating machine oil and the liquid refrigerant sometimes accumulate. If the refrigerating machine oil accumulates in the second container, there is an apprehension that the amount of oil in the compressor is insufficient. Therefore, the aforementioned state should be avoided in order to reliably operate the refrigeration and air conditioning circuit. The eighth and ninth embodiments have the structure comprising a movement element for returning liquids, such as the refrigerating machine oil and the liquid refrigerant accumulated in the second container to the first container 1 when the operation of the refrigeration and air conditioning circuit is interrupted or when the refrigerant gas 9 is not introduced. The above structure will now be described. Eighth Mode An accumulator will now be described according to the eighth embodiment of the present invention and adapted to a refrigeration and air conditioning circuit. Figure 12 (a) is a side cross-sectional view. In this embodiment, a state is assumed in which the opacified refrigerating machine oil and the liquid refrigerant are introduced into the second container 2. Thus, the refrigerating machine oil mixed and introduced into the second container is returned to the first container. Therefore, the first container is disposed in a lower position and a communication tube is provided to establish communication between the upper portion in the first container and the lower portion in the second container. Referring to the drawings, the reference numeral 31 represents a movement element for moving the accumulated liquid in the second space, which is the second container 2 in this mode. The movement element is, for example, a communication tube that is composed of a communication element to establish the connection between a position adjacent to the bottom portion of the second container 2, which is a liquid accumulation portion, and the upper portion of the first container 1. The reference numeral 10a represents the liquid refrigerant and Ha represents the refrigerating machine oil accumulated in the second container 2. In this embodiment, the second container 2 is disposed above the first container 1. Figure 12 shows a state performed during the operation. In this case, a pressure loss occurs in the gas passage tube, causing the pressure in the second container to be lower than that of the first container 1. The above difference in pressure prevents the downward movement of the liquid refrigerant 10a and the refrigerating machine oil Ha in the second container 2 to the first container 1 through the movement element 31. Thus, the refrigerant gas 9 flows upwards into the second container 2. When the operation of the refrigeration and air conditioning circuit is has interrupted, the pressures in the first container 1 and in the second container 2 are made equal. Thus, the liquid refrigerant 10a and the oil for cooling machine A have accumulated in the second container 2 and are lowered into the first container 1 by force of gravity. When the refrigeration and air conditioning circuit have been operated, the liquid refrigerant 10 moved to the first container 1 is allowed to pass through the communication tube 8, and then it is introduced into the gas passage tube 4. Then, the liquid refrigerant 10 moves to the second container 2. On the other hand, the oil for cooling machine 11 returned to the first container 1 flows from the return pipe 6 to the compressor.

When the operation and interruption of the cooling and air conditioning circuit are repeated, the refrigerating machine oil Ha accumulates in the second container 2 by force of the sequential operation can be recovered inside the compressor through the first container 1. Figure 13 shows a state in which the position of the upper end of the communication tube that establishes the communication between the portion of the bottom in the second container 2 and the upper portion in the first container 1 is different from that of the structure shown in Figure 12 (a). Referring to the drawing, the reference numeral 31a represents a communication tube having a top end open in the gas space in the second container 2. Moreover, a communication hole 32b is formed in the liquid accumulation portion in the lower portion in the second container 2. In the aforementioned structure, the difference in pressure occurs in a state shown in Figure 13 similarly to the state shown in Figure 12 (a) during the operation of the apparatus. Therefore, the refrigerant gas 9 is introduced into the upper portion in the second container 2. On the other hand, the refrigerating machine oil Ha does not move down inside the first container 1. After the cooling circuit and air conditioner has been interrupted, the liquid refrigerant 10a and the refrigerating machine oil Ha is allowed to pass through the communication hole 31b and accumulated in the second container 2 move downwards inside the first container 1. [0073 That is, the Refrigerant gas 9 can be moved to the gas space in the second container 2 during operation. After the operation of the apparatus has been interrupted, the liquid refrigerant 10a and the oil for cooling machine Has accumulated in the second container 2 can be returned to the first container 1 through the communication hole 31b. Ninth Modality The structure of an accumulator according to a ninth embodiment of the present invention and adaptable to a refrigeration and air conditioning circuit will now be described. Figure 14 is a vertical cross-sectional view showing the accumulator according to this embodiment. Figure 14 shows a state in which the refrigeration and air conditioning circuit is operated. Referring to the drawing, the reference numeral 32 represents a communication tube serving both a liquid communication element and a gas communication element, the communication tube 32 being a gas communication tube 32 in this mode . The reference numeral 33 represents a communication element for establishing communication between the liquid accumulation portion in the second container 2 and an intermediate position of the communication tube 32, the communication element 33 being a communication tube. This embodiment also has the structure that the second container 2 is disposed above the first container 1. Moreover, the communication tube 33 and the gas communication tube 32 establish the communication between the liquid accumulation portion in the second container 2 and the first container 1. In this embodiment, it is assumed that the refrigerating machine oil and the liquid refrigerant are opacified and introduced into the second container. Thus, the oil for refrigerating machine mixed and introduced into the second container is returned to the first container. A liquid return hole is formed on the side surface of the gas communication tube connected to the second container. Moreover, the liquid return hole and the portion of the second container are allowed to communicate with each other. Now the operation will be described. Now we will describe the pressure in the accumulator that is made during the operation. It is assumed that the pressure in the first container 1 is Pl, the pressure in the second container 2 is P2 and the pressure in the gas communication tube 32 is P3. As a pressure loss occurs due to gas flow, the pressure has the relationships that satisfy Pl >; P3 > P2 Therefore, the liquid refrigerant 10 and the oil for refrigerating machine 11 are mixed with the refrigerant gas and are allowed to flow from the first container 1 to the gas communication tube 32 during the operation to follow the flow of the refrigerant gas. They are then allowed to pass through an open end of the gas communication tube 32 or the communication tube 33, and then are introduced into the second container. Thus, the liquid refrigerant 10a and the oil for refrigerating machine Ha, together with the refrigerant gae, accumulate in the second container 2. In a state of interruption of the operation, the density makes the liquid refrigerant 10a and the oil for refrigerating machine It has accumulated in the second container 2, flows through the communication tube 33 and the gas communication tube 32, and then moves to the first container 1. As the first container 1 remains at rest, the liquid refrigerant 10 and the oil for refrigerating machine 11 naturally separate from each other in the lower portion of the first container. When the operation has been restarted, the refrigerating machine oil 11 in the first container 1 is returned to the compressor through the oil return pipe. Thus, the liquid refrigerant 10, together with the refrigerant gas 9, moves to the second container. As a result of the aforementioned operation, the refrigerating machine oil Has accumulated in the second container 2 can be recovered inside the compressor. The eighth and ninth modes are structured on the assumption that the refrigerant machine oil Ha in a small amount is introduced into the second container 2 during the operation of the refrigeration and air conditioning circuit. Thus, an element that returns the refrigerating machine oil is accumulated in the second container 2 to the first container 1 when the operation of the refrigeration and air conditioning circuit is interrupted. Each of the tenth, eleventh and twelfth embodiments has a movement element that is capable of returning the refrigerating machine oil. It has accumulated in the second container 2 to the first container 1 and it is necessary to interrupt the refrigeration and air conditioning circuit, that is , even during the operation of the refrigeration and air conditioning circuit. Tenth Mode An accumulator will now be described according to a tenth embodiment of the present invention. This method is also structured in the assumption that the refrigerating machine oil and the liquid refrigerant are opacified and introduced into the second container. Thus, the refrigerant machine oil mixed and introduced into the second container is returned to the first container. The first container is disposed below the second container. Moreover, an intermediate container is disposed between the first container and the second container. The first container and the intermediate container are connected to each other by means of an open / closed valve in such a way that it is allowed to open and close. In addition, the second container and the intermediate container are connected to each other by an open / closed valve in such a way that opening and closing is allowed. Figure 15 is a tranevereal cutoff that moves the accumulator according to this modality. The above drawing shows an assembly made during the operation of the refrigeration and air conditioning circuit. Referring to the drawing, the reference numeral 34 represents a third space which is an intermediate container formed in the intermediate portion between the first container 1 which is the first space and the second container 2 which is the second space. Reference numerals 37a, 37b, 37c and 37d repre- sent communication tubes that establish the connection between the upper portion in the first container 1 and the bottom portion of the second container 2 through the intermediate container 34.

The communication tubes 37a and 37b between the intermediate container 34 and the second container 2 are opened / closed by the first open / close valve 35. The communication tubes 37c and 37d between the intermediate container 34 and the first container 1 are opened / close by the second open / close valve 36. Now the operation will be described. This embodiment has a structure in which the first and second open / close valves 35 and 36 are opened / closed alternately during the operation of the cooling and air conditioning circuit so that the liquid refrigerant 10a and the refrigerating machine oil have accumulated. in the second container 2 are returned to the inner portion of the first container 1. During the operation of the refrigeration and air conditioning circuit, the relation Pl < P2 ee eatisface when both of the first and second open / close valves 35 and 36 are open. Therefore, the liquid refrigerant 10a and the oil for refrigerating machine 11b accumulated in the second container can not be returned to the inner portion of the first container 1. When the first open / close valve 35 was opened to close the second valve of open / close 36 as shown in Figure 16 (a), the portion in the intermediate container 34 and that of the second container 2 makes them equal. As a result, the liquid refrigerant 10a and the refrigerating machine oil Ha move from the second container 2 to the intermediate container 34 by force of gravity. Then, the first open / closed valve 35 is closed and the second open / closed valve 36 is opened as shown in Figure 16 (b) so that the pressure in the intermediate container 34 and that of the first container is made They are the same. Thus, the liquid refrigerant 10a and the oil for refrigerating machine A have accumulated in the cylinder 134 move from the intermediate container 34 to the first container 1 by force of gravity. The aforementioned operation is repeated so that the liquid refrigerant 10a and the refrigerating machine oil Has accumulated in the second container 2 are returned to the inner portion of the first container 1 even during the operation of the refrigeration and air conditioning circuit. In some cases an appropriate element for controlling the opening / closing can be used to detect the level of the liquid in the second container 2 so as to control the opening / closing of the first and second open / close valves 35 and 36 according to the liquid level arranged. As an alternative to this, the opening and closing of the first and second open / close valves 35 and 36 is controlled. Thus, the opening and closing of the first and second open / close valves 35 and 36 are controlled. Eleventh Mode The structure of an accumulator according to an eleventh embodiment of the present invention and adaptable to the refrigeration and air conditioning circuit will now be described. In this mode, it is assumed that the oil for the refrigerating machine and the liquid refrigerant are opacified and introduced into the second container. Thus, the oil for refrigerating machine mixed in the second container is returned to the first container. The structure according to this embodiment is formed in such a way that a plurality of communication tubes each projecting on the internal wall of the suction tube connected to the first container are allowed to communicate with the second container. Figure 17 is a cross-sectional vieta showing the accumulator according to this embodiment in such a way that a portion is enlarged so as to be illustrated simultaneously. Referring to the drawing, the reference numeral 38 represents an introduction element for introducing the refrigerant gas, the refrigerating machine oil and the liquid refrigerant circulating in the refrigeration and air conditioning circuit inside the first container 1., the introduction element being, for example, a suction tube. The reference numeral 39 represents a connecting element for establishing communication between the introduction element 38 and the liquid accumulation portion in the second container 2, the connection element being, for example, an oil recovery tube. Plural (eg tree) oil recovery tubes are provided. A higher oil recovery tube 39a between the plural oil recovery tubes 39 is disposed adjacent to the highest level of liquid that accumulates in the second container 2. In order to recover the refrigerating machine oil Ha within the first Container 1, even when the level of the liquid exists in any position in the second container, it has plural lines, which in this mode are two, the oil recovery tubes 39b and 39c are disposed apart from each other in a vertical direction. One end of the oil recovery tubes 39 adjacent to the introduction element 38, as illustrated in an enlarged manner, is allowed to project inwardly on the inner surface of the insertion element 38 by about several millimeters. On the other hand, another end of the oil recovery tubes 39 ee connects to the lower portion of the second container 2. Now the operation will be described. The pressure at the front end of the oil recovery tubes 39 is made to be lower than the eetática pressure in the oil recovery tube 39 due to an influence of the fluid flow which is introduced from the refrigeration and air circuit. conditioned inside the first container 1. As a result, the pressure at the front end of the oil recovery tubes is made to be P4. Assuming that the prediction in the first container 1 ee Pl and the one in the second container 2 ee P2, the relation Pl >; P2 ee eatisface during the operation. Therefore, the relation P4 < P2 must be operated to cause the refrigerating machine oil Ha and the liquid refrigerant 10a accumulated in the second container 2 to flow into the introduction element 38. Therefore, the oil recovery tubes are projected into the introduction element. 38 by an appropriate length. Here, a so-called ejector effect is used so that a P4 < P2 Like the relation P4 < In the cooling and air conditioning circuit, the refrigerating machine oil has been introduced into the second container 2, together with the liquid refrigerant 10a, into the introduction element 38, and then into the first container 1. As the second container 2 is disposed above the first container 1, the liquid refrigerant 10a and the oil for the refrigerating machine Ha in the second container 2 are allowed to drain through the oil recovery tube 39 attributable to the deneity when the operation of the cooling circuit and air conditioning is interrupted. Then, the liquid refrigerant 10a and the refrigerating machine oil Ha move the first container 1. As described above, the structures of the gas passage tube 4, the tube of the air duct 7 and the communication tube 8 mainly make that the liquid refrigerant 10 selectively moves to the second container 2. Even if the unsuitable movement results in the refrigerating machine oil being mixed with the liquid refrigerant and the refrigerating machine oil being introduced into the second container 2, this mode allows that the refrigerating machine oil has introduced into the second container is recovered in the first container 1. Then, the refrigerating machine oil is recovered inside the compressor through the oil return pipe 6. Therefore, a required quantity is it can maintain without the reduction of the flow regime of the liquid refrigerant 10 to the compressor. As a result, the reliability of the refrigerator and that of the refrigeration and air conditioning circuit can be increased. Twelfth Mode The structure of an accumulator according to a twelfth embodiment of the present invention and adaptable to the refrigeration and air conditioning circuit will now be described. In this mode, it is assumed that the refrigerating machine oil and the liquid refrigerant are opacified and introduced into the second container. Thus, the oil for refrigerating machine mixed and introduced into the second container is recovered inside the first container. A tube having a plurality of holes is disposed in the second container. Still, the portion of the lower end of the tube is allowed to project on the inner wall of the eduction tube which is connected to the first container. Figure 18 is a vertical cross-sectional view showing the accumulator according to this modality in such a way that an increased portion is added. Referring to the drawing, the reference numeral 40 repre- sents an introduction element which is, for example, an eduction tube. The reference numeral 41 repre- sents a liquid recovery element which is, for example, an oil recovery tube in the form of a hollow cylinder die-cut so as to be immersed in the liquid accumulation portion in the second container 2. A plurality of oil recovery holes 41a are formed vertically at the lateral surface of the oil recovery tube 41. The highest pore of the oil recovery hole 41a causes it to be adjacent to the highest position of the liquid level. which accumulates in the second container 2. To recover the oil for refrigerating machine Ha within the first container 1 even if the level of the liquid exists in an arbitrary positionThe plural oil recovery hole 41a is formed in the vertical direction. The reference numeral 42 represents a connection element for establishing communication between the lower end portion of the oil recovery tube 41 and the suction tube 40, the connection element being, for example, an oil recovery tube. One end of the oil recovery tube 42 adjacent the suction tube 40 is allowed to project inwardly on the inner wall of the suction tube 40 in, for example, about several millimeters. Now he will describe the operation. Even if the level of the refrigerating machine oil has accumulated in the second container 2 is in an arbitrary position, the refrigerating machine oil Ha is introduced into the oil recovery tube 41 through the oil recovery hole 41a formed in the oil level. On the other hand, the refrigerating machine oil Ha is introduced into the oil recovery tube 41 through the oil recovery hole 41a facing the liquid refrigerant 10a. The ejector effect is exerted on the end of the oil recovery tube 42 adjacent the suction tube 40 due to the refrigerant gas 9 flowing in the suction tube 40. Thus, the pressure ee makes it lower than the surrounding static pressure. Assuming that the pressure at the front end of the recovery tube 42 in the suction tube 40 is P5, a state satisfying P5 is performed.; P2 As a result, the refrigerating machine oil Ha and the liquid refrigerant 10a introduced into the recovery tube 41 are sucked into the eduction tube 40, and then recovered into the first container 1 together with the refrigerant gae. As described above, the refrigerating machine oil has been introduced into the second container 2 during the operation recovers inside the first container 1. During the interruption of the refrigeration and air conditioning circuit, the liquid refrigerant 10a and the refrigerating machine oil have in the second container 2, by gravity, they are allowed to move through the oil recovery tube 41 and move to the first container 1. As a result of the aforementioned operation carried out by the structure in accordance with this modality, the machine oil The refrigerant introduced into the second container 2 can be recovered inside the first container 1 even when an inefficient operation to electively move the liquid refrigerant 10 to the second container 2 causes the refrigerating machine oil 11 to mix with the liquid refrigerant 10a and the oil for refrigerant machine Ha is introduced inside the segu Container 2. The recovered liquid refrigerant 10 is allowed to pass through the oil return pipe 6 so as to be recovered in the compressor. Therefore, a required amount can be maintained without reduction in the flow rate of the refrigerating machine oil to the compressor. As a result, the reliability of the compreeor and that of the refrigeration and air conditioning circuit can be improved. Thirteenth Modality The structure of an accumulator according to a thirteenth embodiment of the present invention and adaptable to the refrigeration and air conditioning circuit will now be described. Also in this mode, it is assumed that the refrigerating machine oil and the liquid refrigerant are opacified and introduced into the second container. Thus, the oil for refrigerating machine mixed and introduced into the second container is re-routed to the first container. A plurality of die-casting communication tubes for projecting onto the inner wall of the eduction tube connected to the first container are left communicating with the second container. Figure 19 is a vertical cross-sectional view showing the accumulator according to this embodiment such that a portion is increased. This modality is a modification of the structure of the eleventh modality. This, the structure according to the eleventh embodiment is applied to the structure according to the second modality. The first container 1 is disposed above the second container 2. Referring to the drawing, the reference numeral 43 repre- sents an eduction tube, and reference numerals 44a, 44b and 44c repre- sent oil recovery tubes. The highest pore (the oil recovery tube pore 44c) causes it to be adjacent to the highest level of liquid that accumulates in the second container 2. To allow the refrigerating machine oil Ha to recover within the second container 2 even if the liquid level is at any position, the plural oil recovery tubes (which in this embodiment are two) 44b and 44c are arranged in the vertical direction. The ends of the oil recovery tubes 44a, 44b and 44c project on the inner surface of the suction tube 43 as illustrated in an enlarged manner, while other ends are connected to the lower portion of the second container 2. As the operation of this modality is the same as the one according to the eleventh modality, the description of the operation is omitted. Also the structure mentioned above is suitable for recovering the refrigerating machine oil It has been introduced into the second container 2 even if the incomplete operation for selectively moving the liquid refrigerant 10 to the second coater 2 causes the refrigerating machine oil 11 to mix with the refrigerant liquid 10a and causes the refrigerating machine oil to be inserted into the second container 2. More, the recovered liquid refrigerant 10 is recovered in the compressor through the oil return pipe 6. Therefore, a reliable cooling and air conditioning circuit can be obtained without reducing the flow rate of the refrigerating machine oil to the compressor. One object of each of the fourteenth and fifteenth modalities is to avoid clutter of the liquid refrigerant and the refrigerating machine oil in the first container 1 and in the second container 2 by the flow of the refrigerant gas 9 in the container to efficiently perform the separation of gas-liquid and the eeparación of the oil for machine refrigerante and of the liquid refrigerante one of the other. Fourteenth Mode The structure of an accumulator according to a fourteenth embodiment of the present invention and adaptable to the refrigeration and air conditioning circuit will now be described. Figure 20 ee a vertical tranevereal cutoff that moves the accumulator according to this mode. The structure is arranged in order to stabilize the level of the liquid (oil level) in the first container 1 and to stabilize the boundary surface between the refrigerating machine oil 11 and the liquid refrigerant 10. Referring to the drawing, the numeral of reference 45 represents a liquid level stabilization plate disposed adjacent the boundary surface between the refrigerating machine oil 11 and the liquid refrigerant 10 in a state in which the liquid refrigerant 10 is accumulated in the first container 1. The numeral reference 46 represents a rectification plate secured above the level of the oil (the level of the liquid) The liquid level stabilization plate and the rectification plate 46 form an element for stabilizing the liquid level to stabilize the level of the liquid in the first container 1. For example, ee must select a wire fabric (a mesh), metal in the foam or ein and einterizado that has a permeability to liquid and satisfactory gas. The refrigerant gas 9, the liquid refrigerant 10 and the refrigerating machine oil 11 are introduced into the first container 1 through the suction tube 3. When the liquid refrigerant 10 and the refrigerating machine oil are allowed to pass through the plate of rectification 46, the energy of the liquid refrigerant 10 and the oil for refrigerating machine 11 is reduced. Thus, the liquid refrigerant 10 and the oil for refrigerating machine are calmly depoeted to the level of the liquid accumulated in the first container 1. On the other hand, the flow direction of the refrigerant gae 9 is changed by the rectification plate 46. thus, the refrigerant gas 9 can not flow easily to the lower portion in the first container 1. Thus, the refrigerant gae 9 easily flows to the gae 4 discharge tube and to the air duct tube 7. To improve the performance of the accumulator , the efficiency in the gae-liquid eeparation ee must be improved to efficiently maintain the liquid refrigerant 10 in the first container 1 and to efficiently remove the liquid refrigerant and the refrigerating machine oil 11 in two layers. To improve the efficiency of the separation, an arrangement must be reached in which the level of the liquid (the level of the oil) in the first container 1 is not disturbed. In order to efficiently remove the liquid refrigerant 10 and the refrigerating machine oil 11 in two layers by force of the specific density difference, the portion adjacent to the boundary surface between the refrigerating machine oil 11 and the liquid refrigerant 10 ee must keep calm whatever is possible. Therefore, the direct collision of the refrigerant gas with the level of the oil is prevented and the penetration of the refrigerant gas is allowed by the use of the rectification plate 46 to change the direction of the flow and the stabilization plate of the liquid level. which has the structure of wire mesh or the structure of the foamed metal. The deposited liquid is quickly separated in the refrigerating machine oil 11 and the liquid refrigerant 10 having high specific density due to the existence of the liquid level stabilization plate 45., the limit surface can be stabilized. Even if the level of the liquid has disturbances, the liquid level stabilization plate 45 is apt to absorb some of the disturbance. As a result, the limit surface and liquid level can be stabilized. This embodiment has a structure that the first container has a cylindrical shape and the suction tube 3 introduces the fluid along the interior surface of the cylinder. Therefore, the fluid is deposited while the energy of the fluid is reduced during the flow along the inner surface of the cylinder. As a result, the rectification plate 46 and the liquid level stabilization plate 45 effectively form a smooth flow. Although this embodiment has the structure that both the liquid level stabilization plate 45 and the rectification plate 46 for the container 1 are provided, the effect of improving the efficiency of the gas-liquid separation can be obtained from a structure in which any of the elements is provided. Fifteenth Modality The structure of an accumulator according to a fifteenth embodiment of the present invention and adaptable to the refrigeration and air conditioning circuit will now be described. Figure 21 is a vertical cross-sectional view illustrating the accumulator according to this embodiment in such a way that a structure for stabilizing the level of the oil (the level of the liquid) in the second container 2 is shown. Referring to the drawing, the reference numeral 47 represents a rectification plate set above the level of the oil (the level of the liquid) in the second container 2 and lower than the position of the opening of the gas passage tube 4. Thus, the direct shock of the refrigerant gas 9 introduced through the gas passage tube 4 with the surface of the refrigerating machine oil Ha in the liquid refrigerant 10a. The rectification plate 47 is made of a material having liquid permeability and satisfactory gae, for example, a structure of woven wire (mesh), foamed metal or sintered metal. The refrigerant gas 9, the liquid refrigerant 10a and the refrigerating machine oil Ha are introduced into the second container 2 through the gae discharge tube 4. At this time, the liquid refrigerant 10a and the refrigerating machine oil 11 accumulate in the second container 2, while the refrigerant gae is charged from the discharge tube 5 to the refrigeration and air conditioning circuit. When the rectification plate 47 having the structure shown above is provided in the second container 2, the direct collision of the refrigerant gae with the surface of the accumulated liquid can be avoided. Thus, the refrigerant gas flows smoothly into the deepening tube 5. From the first to the thirteenth modalidade they have the structure formed by two containers that are the first container 1 and the second container 2 to obtain an effect of separating the oil for refrigerating machine and the liquid refrigerant one from the other to efficiently return the refrigerating machine oil to the compressor. The thirteenth to the twenty-third embodiments have a structure in which a separation plate is provided in a container to form two spaces (first and second spaces). In this case, ee can obtain a similar effect due to a similar operation so that the first and second containers according to the first to the thirteenth modes. Moreover, the structure can be simplified and the size of the apparatus can be reduced. Sixteenth Modality The tenth modality has a structure in which an accumulator, according to the second modality, is formed by a container. Now the accumulator will be described according to this mode. Figure 22 (a) is a vertical cross-section vieta according to this modality. Figure 22 (b) is a cross-sectional view taken along the line X-X shown in Figure 22 (a). Referring to the drawings, the reference numeral 60 represents an accumulator container and 61 represents a dividing plate for vertically dividing the inner portion of the accumulator container 60. The reference numeral 62 represents a first space, 63 represents a second space, 64 represents a tube of the invention, 65 represents a gas communication tube, 66 represents an air duct tube, 67 represents a communication tube, 68 represents an induction tube and 69 represents an oil return tube corresponding to the return tube of oil. In this embodiment, the first container l according to the second embodiment corresponds to the first space 62 and the second container 2 corresponds to the second space 63. The same or corresponding elements were given the same names and have an eimilaree function. Although the structure is omitted in the second embodiment, the charging tube 5 is usually connected from the second container 2 to the compressor and also the oil return tube 6 is connected to the compressor of the second container 2. In this embodiment, the tube oil return 69 and discharge tube 68 are allowed to communicate with each other in the accumulator container 60. Moreover, the discharge tube 68 for discharging the refrigerant gas and the refrigerating machine oil is connected to the compressor. The height hl from the bottom surface in the first space 62 to the oil return tube 69, the height h2 from the bottom surface in the first space 62 to the communication tube 67 and the height h3 of the bottom surface in the first space 62 to the lower end of the air duct tube 66 the relationship h3 <; hl < h.2. The upper end of the air duct tube 66 is substantially open at the same position as the upper end of the gae communication tube 65. When the level of the liquid (the level of the oil) in the first space 62 is in a lag between h3 and h2, the refrigerant gas is introduced into the gas communication tube 65 from the air duct tube 66 through the communication tube 67. At this time, the liquid refrigerant is introduced into the portion of the lower end of the tube of air duct 66 by an amount corresponding to the level of the liquid. When the liquid level (the oil level) rises to be no less than h.2, the liquid refrigerant is introduced from the air duct tube 66 into the gas communication tube 65 through the communication tube 67 The liquid refrigerant moves to the second space 63 formed in the lower position due to the gravity and the flow of the inner gas so as to accumulate in the bottom portion in the second space 63. Thus, the level of the liquid in the first space 62 goes down. As noted above, the level of substantially liquid liquid (oil level) h2 is maintained in the first space 62. An excessive portion of liquid refrigerant accumulates in the second space 63. Thus, in a case where the oil for refrigerating machine which has little solubility with the liquid refrigerant is used in the refrigerating and air conditioning circuit, the flow rate of the refrigerating machine oil flowing from the oil return tube 69 inside the compressor through the discharge pipe 68 ee can cause it to be a connector, as shown in Figure 2. As a result, a required amount can be maintained without reducing the flow rate of the refrigerating machine oil to the compressor. Thus, the reliability of the compressor and that of the refrigeration and air conditioning circuit can be improved. Since the suction tube 64 and the discharge tube 64 are connected to the accumulator container 60, an accumulator having a simple appearance can be obtained.

Seventeenth Modality A seventeenth modality is a modification of the sixteenth modality in such a way that the first space and the second space are formed horizontally. An accumulator according to this embodiment will now be described. Figure 23 (a) is a vertical traneversal cutout that shows an accumulator according to this modality. Figure 23 (b) is a cross-sectional view taken along the X-X line shown in Figure 23 (a). Referring to the drawing, the reference numeral 70 represents an accumulator container and 71 represents a partition plate and 71 represents a partition plate for dividing the interior portion of the accumulator container 70. the reference numeral 72 repre sents a first space, 73 represents a second space, 74 repre- sents an eduction tube, 75 repre- sents a gae communication tube, 76 repre- sents an air duct tube, 77 repre- sents a communication tube, 78 represents an induction tube and 79 repre- sents a tube of oil regreeo. The height hl of the bottom surface in the first space 72 to the oil return tube 79, the height h2 from the bottom surface in the first space 72 to the communication tube 77 and the height h3 from the bottom surface in the first space 72 to the lower end of the air duct pipe 76 satisfy the relation h3 < hl < h2. The upper end of the air duct tube 76 is open to substantially the same position as the popping of the upper end of the gae communication tube 75. When the level of the liquid (the level of the oil) in the first space 72 is in a range from h3 haeta h2, the refrigerant gas is introduced from the air duct tube 76 to the gas communication tube 75 through the communication tube 77. At this time, the cooling liquid has been introduced in the lower end portion of the air duct tube 76 by an amount corresponding to the level of the liquid. When the level of the liquid (the oil level) is made to be no less than h2, the liquid refrigerant is introduced from the air duct tube 76 into the gas communication tube 75 through the communication tube 77. The The liquid refrigerant moves to the second space 73 as the internal gas moves so that the liquid refrigerant accumulates in the bottom portion in the second space 73. As a result, the liquid level in the first space 72 is lowered. As a result, the substantially constant liquid level (the oil level) of h2 ee can be maintained in the first space 72. If an excess portion of the liquid refrigerant is accumulated in the second space 73. When it is used for refrigerating machine it it has little solubility with the liquid refrigerant in the refrigeration and air conditioning circuit as shown in Figure 2, the flow rate of the refrigerating machine oil which flows from the oil return tube 79 to the compressor can be done eea conetante. Thus, a required amount can be maintained with no reduction in the flow rate of the refrigerating machine oil to the compressor. As a result, the reliability of the compressor and that of the refrigeration and air conditioning circuit can be improved. Since the suction tube 74, the discharge tube 78 and the oil return tube 79 are connected to the accumulator container 70, an accumulator having an overall appearance can be obtained. Eighteenth Modality A eighteenth modality has a structure as the structure according to the sixth modality and is performed by means of a container and the first space is formed next to the second space. Now the accumulator will be described according to this modality. Figure 24 is a vertical cross-sectional view showing the accumulator according to this embodiment. Figure 24 (a) shows the complete body of the accumulator, and Figure 24 (b) shows a partially enlarged vieta. Referring to the drawings, the reference numeral 80 represents an accumulator container and 81 represents a dividing plate for dividing the internal portion of the accumulator container 80. The reference numeral 81a represents a gae communication hole formed in the partition plate, 82 represents a first space, 83 represents a second space, 84 represents a suction tube, 85 represents a separating plate, 86 represents a refrigerant suction tube, 87 represents a discharge tube and 88 represents a tube of suction. return of oil. Moreover, a gap is formed between each of the lower ends of the separation plate 85 and the refrigerant suction tube 86 and the bottom surface in the first space 82. The first container 1 according to the sixth embodiment corresponds to the first space 82, the second container 2 corresponds to the second space 83, the gas communication tube 22 corresponds to the gas communication hole 81a, the cylinder 23 corresponds to the separation plate 85 and the refrigerant suction pipe 24 corresponds to the coolant eduction pipe 86. The height hl of the bottom surface in the first space 82a the oil return pipe 88, the height h2 of the bottom surface in the first space 82a the pipeline of eduction coolant 86 and the height h3 from the bottom surface in the first space 82 to the lower end of the separation plate 85 satisfy the ratio h3 <; hl < h2.

During the operation of the refrigeration and air conditioning circuit, the refrigerant gas flows from the first space 82 haeta the second space 83 through the gae communication hole 81a. Therefore, a loss of pressure occurs. That is, the pressure in the first space 82 is greater than that of the second space 83. When the liquid level (the oil level) in the first space 82 is in a range from h3 to h2, the refrigerant gas is introduced into the space 82. the refrigerant suction tube 86. Thus, the pressure difference causes the refrigerant gas to be pushed up into the suction tube of the refrigerant 86. At this time, the liquid refrigerant has been introduced from the lower end of the refrigerant plate. separation 85 to the portion in which the refrigerant suction pipe 86 is disposed by an amount corresponding to the liquid level. When the liquid level (the oil level) makes it no less than h2, the liquid refrigerant is introduced into the coolant eduction tube 86 so that it is pushed up into the coolant suction pipe 86 due to the difference in pressure. Therefore, the liquid refrigerant 10 in the first space 82 moves to the second space 83, and accumulates in the bottom portion in the second space 83. As a result, the level of the liquid in the first space 82 lowers. As described above, the level of liquid permanently constant (the oil level) of h2 ee can be maintained in the first space 82. Aei, an excess portion of the liquid refrigerant is accumulated in the second space 83. When using machine oil refrigerant having low solubility with the liquid refrigerant in the refrigeration and air conditioning circuit as described with reference in Figure 2, the flow rate of the refrigerating machine oil which flows from the oil return pipe 88 to the compressor ee can make it a conetante. As a result, a required amount can be maintained without reduction in the flow rate of the refrigerating machine oil to the purchaser. Thus, the reliability of the compressor and that of the refrigeration and air conditioning circuit can be improved. Since only the eduction tube 84, the deepening tube 87 and the oil return tube 88 are connected to the accumulator container 80, it can obtain an accumulator which has an overall appearance. Nineteenth Modality A nineteenth modality has a structure as the structure according to the eighth modality and is carried out by means of a container. Now an accumulator will be described according to this mode. Figure 25 (a) is a vertical cross-sectional view showing an accumulator according to this modality. Figure 25 (b) is a cross-sectional view taken along the X-X line shown in Figure 25 (a). Referring to the drawings, the reference numeral 89 represents an accumulator container and 90 represents a partition plate for vertically dividing the inner portion of the accumulator container 89. The reference numeral 91 represents a first space, 92 represents a second space 93 represents an eduction tube, 94 represents a gas communication tube, 95 represents an air duct tube, 96 represents a communication tube, 97 represents a communication tube, 98 represents a discharge tube and 99 represents a oil return tube. The first container 1 according to the eighth embodiment corresponds to the first space 91, while the second container 2 corresponds to the second space 92. The height hl from the bottom surface in the first space 91 to the oil return pipe 99, the height h2 from the bottom surface in the first space 91 haeta the communication tube 96 and the height h3 of the bottom surface in the first space 91 haeta the lower end of the air duct tube 95 the relation h3 < hl < h2. The upper end of the air duct tube 95 is open in substantially the same position as the position of the upper end of the gas communication tube 94.

When the level of the liquid (the level of the oil) in the first space 91 is in a range from h3 to h2, the refrigerant gas is introduced from the air duct tube 95 to the gas communication tube 94 through the tube communication 96. At this time, the coolant has been introduced from the lower end portion of the air duct tube 95 by an amount corresponding to the level of the liquid. When the level of the liquid (the oil level) becomes no less than h2, the liquid refrigerant is introduced from the air duct tube 95 into the gas communication tube 94 through the communication tube 96. Entoncee , the liquid refrigerant ee moves to the second space 92 as the internal gae moves, and then accumulates in the bottom portion in the second space 92. Aei, the liquid level in the first space 91 is lowered. During the operation of the refrigeration and air conditioning circuit, the introduced refrigerant gas flows from the first space 91 to the second space 92 through the gas communication hole 94, resulting in a loss of pressure. Thus, the pressure in the first space 91 is greater than that of the second space 92. Therefore, the liquid refrigerant moved to the second space 92 is not returned to the first space 91 of the communication tube 97. However, the difference in the precession between the inner portion of the first space 91 and the inner portion of the second space 92 is eliminated. Thus, the liquid refrigerant accumulated in the second space 92 is returned from the communication tube 97 to the first space 91 by force of gravity. As described above, the level of the substantially constant liquid (the oil level) of h 2 ee can be maintained in the first space 91. Moreover, an excessive portion of the liquid refrigerant accumulates in the second space 91. When oil is used for refrigerating machine that has poor solubility with the liquid refrigerant in the refrigeration and air conditioning circuit as shown in Figure 2, the flow rate of the refrigerating machine oil which flows from the oil return tube 99 to the compressor ee It can make it constant. Thus, a required amount can be maintained without reduction in the flow rate of the refrigerating machine oil to the compressor. Thus, the reliability of the compressor and that of the refrigeration and air conditioning circuit can be improved. Since the suction tube 93, the deepening tube 98 and the oil return tube 99 are connected to the accumulator container 89, an accumulator having a simple appearance can be obtained. Twentieth Modality A twentieth modality has a structure like that of the accumulator that has the structure according to the ninth modality and is performed by means of a container. Moreover, the second container is in the first container. Now the accumulator will be described according to this modality. Figure 26 (a) is a view in vertical transvereal section that shows an accumulator according to this modality. Figure 26 (b) is a top view. Referring to the drawings, the reference numeral 100 represents an accumulator container and 101 represents an inner container for removing the inner portion of the accumulator container 100. The reference numeral 102 repre sents a first space separated by the container 101. The numeral reference 103 repre sents a second space, 104 rejects an eduction tube, 105 repre sents a gas communication tube, 105 a represents a communication hole, 106 represents an air duct tube, 107 represents a communication tube, 108 represents a oil return tube and 109 represents an induction tube. In this embodiment, the first container 1 according to the ninth embodiment corresponds to the first space 102, the second container 2 corresponds to the second space 103 and the communication tube 33 corresponds to the communication hole 105a. The same or corresponding elements to those of the ninth modality are given the same names and have the same functions. The height hl from the bottom surface in the accumulator container 100 to the oil return tube 108, the height h2 from the bottom surface in the accumulator container 100 to the communication tube 107 and the height h3 from the bottom surface in the accumulator container 100 to the lower end of the air duct tube 106 are the ratio h3 <; hl < h2. The upper end of the air duct tube 106 is opened in substantially the same position as that of the open end of the gas communication tube 105. When the level of the liquid (the level of the oil) in the accumulator container 100 is in a range from h3 to h2, the refrigerant gas is introduced from the air duct tube 106 to the gas communication tube 105 through the communication tube 107. At this time, the refrigerant liquid has been introduced from the portion bottom end of the air duct tube 106 by an amount corresponding to the level of the liquid. When the liquid level (the oil level) has been raised to a level no lower than h2, the liquid refrigerant is introduced from the air duct tube 106 into the gas communication tube 105 through the communication tube 107 The liquid refrigerant ee moves to the second space 103 as the internal gas moves, and then accumulates in the bottom portion in the second space 103. As a result, the level of the liquid in the accumulator container 100 is lowered. During the operation of the refrigeration and air conditioning circuit, the refrigerant flows from the accumulator container 100 to the first space 102 through the gae communication tube 105. There is a loss of preemption. That is, the pressure in the accumulator container 100 is greater than the pressure in the first space 102. Therefore, the liquid refrigerant moved to the second space 103 is not returned from the communication tube to the accumulator container 100. When the The operation of the refrigeration circuit and air conditioner has been interrupted, the difference in the pressure between the inner portion of the accumulator container 100 and that of the second space 103 is eliminated. As a result, the liquid refrigerant accumulated in the second space 103 is regressed from the gas communication tube 105 to the accumulator container 100. As described above, the substantially constant liquid level (the oil level) of h2 can be keep in the accumulator container 100. Moreover, an excessive portion of the liquid refrigerant accumulates in the second space 103. Therefore, when using oil for refrigerating machine having poor solubility with the liquid refrigerant in the refrigerant circuit and air conditioner, the flow rate of the oil for refrigerating machine which flows from the oil return tube 108 to the compressor can be made constant, as shown in Figure 2. As a result, the generation of a defect in the compressor. Since only the suction tube 104, the oil return tube 108 and the discharge tube 109 are connected to the accumulator container 100, an accumulator having a simple appearance can be obtained. Figure 27 shows a modification of the gas communication tube. In this modification, a plurality of communication holes, for example, communication holes 110a and 110b, are formed vertically at different positions of the gas communication tube 110 disposed in the second space. Since communication holes 110a and 110b are formed at different positions, the level of liquid accumulated in the second space does not change. When the operation of the refrigeration and air conditioning circuit is interrupted, the liquid can efficiently return to the first space. If oil is introduced to the refrigerating machine and the oil is allowed to settle on top of the liquid storage portion, the refrigerating machine oil can be gently re-added to the first space.

Twenty-first Modality A twenty-first modality has a structure as the accumulator according to the twelfth modality and is performed by means of a container and the first container and the second container are divided by a division plate. An accumulator according to this embodiment will now be described. Figure 28 (a) is a vertical cross-sectional view showing an accumulator according to this embodiment. Figure 28 (b) is a cross-sectional view taken along the line X-X shown in Figure 28 (a). Referring to the drawings, reference numeral 111 repre- sents an accumulator container and 112 represents a partition plate for vertically dividing the interior portion of accumulator container 111. Reference numeral 113 represents a first space, 114 represents a second space 115 depicts an eduction tube, 116 represents a gas communication tube, 117 represents an air duct tube, 118 represents a communication tube, 119 represents an oil return tube, 120 represents a discharge tube and 121 and 122 represent oil recovery tubes. In this embodiment, the first container 1 according to the twelfth modality corresponds to the first space 113, while the second container 2 corresponds to the second space 114. To the elements equal or corresponding to those according to the twelfth modality ee reads dan loe miemoe name and have the same functions. The height hl from the bottom surface in the first space 113 to the cooling machine oil 11, the height h2 of the bottom surface in the first space 113 to the communication tube 118 and the height h3 of the bottom surface in the first space 113 haeta the lower end of the air duct tube 117 satiefacen the ratio h3 < hl < h2. Moreover, the upper end of the air duct tube 117 is open substantially the same as that of one of the open ends of the gas communication tube 116. When the liquid level (the oil level) in the first space 113 is in a range from b.3 to h2, the cooling gae ee enters from the air duct tube 117 to the gae communication tube 116 through the communication tube 118. At this time, the cooling liquid ee It has introduced from the lower end portion of the air duct tube 117 by an amount corresponding to the level of the liquid. When the level of the liquid (the oil level) makes it not less than h2, the liquid refrigerant is introduced from the air duct tube 117 into the gas communication tube 116 through the communication tube 118.

The liquid refrigerant moves to the second space 114 as the internal gae moves, and then accumulates in the bottom portion in the second space 114. As a result, the level of the liquid in the first space 113 is lowered. As described above, the level of the substantially constant liquid (the oil level) of h2 can be maintained in the first space 113. Moreover, an excess portion of the liquid refrigerant is accumulated in the second space 114. Therefore, when it is oil For refrigerating machine that has low solubility with the liquid refrigerant in the refrigeration and air conditioning circuit as shown in Figure 2, the flow rate of the refrigerating machine oil flowing from the oil return pipe 119 to the compressor It can make you a stranger. As a result, you can avoid generating a defect in the compressor. The oil recovery tube 121 has a plurality of oil recovery holes at different positions in the vertical direction of the honeycomb. The oil recovery tube 121 is designed to be emersed in the liquid accumulation portion in the second space 114. The highest position of the oil recovery hole is made to be in a position adjacent to the highest liquid level in the reservoir. the second space 114. Even if the level of the liquid, of the liquid accumulated in the second space 114 is at any height, the oil for refrigerating machine separated on the liquid can be recovered in the first space 113. To achieve this, a plurality of oil recovery holes are formed vertically. The oil recovery tube 122 for establishing communication between the lower end portion of the oil recovery tube 121 and the suction tube 115 has an end projecting onto the inner surface of the suction tube 115 in, for example, approximately a few millimeters. Now the operations of the oil recovery tubes 121 and 122 will be described. Although the refrigerating machine oil accumulated in the second space 114 is placed in any position, the refrigerating machine oil is introduced into the oil recovery tube 121 from the oil recovery hole corresponding to the oil level. Thus, the cooling liquid is introduced into the oil recovery tube 121 through the oil recovery hole facing the liquid refrigerant. As a result of the ejection effect obtained by the internal flow in the suction tube 115 and exerted on the forward end of the oil recovery tube 122, the pressure at the leading end is made to be a negative pressure as compared to the surrounding static pressure. . As a result, the refrigerating machine oil and the liquid refrigerant introduced into the oil recovery tube 122 are sucked into the suction tube 115, and then recovered in the first space 113. As described above, the refrigerating machine oil introduced into the second space 114 can be recovered in the first space 113 even during the operation of the refrigeration and air conditioning circuit. During the interruption of the operation of the refrigeration and air conditioning circuit, the liquid in the second space 114 moves towards the first space 113 through the oil recovery tubes 121 and 122 due to gravity. As a result of the aforementioned operation, this mode is capable of recovering the refrigerating machine oil introduced into the second space 114 in the first space 113 even if the operation of selectively moving the refrigerant liquid to the second space 114 is not satisfactory and thus the The oil for the refrigerating machine is mixed with the liquid refrigerant and thus the oil for the refrigerating machine is mixed and introduced into the second space 114. Still, the oil for the refrigerating machine is recovered in the compressor through the oil return pipe 119. Therefore, a reliable refrigeration and air conditioning circuit can be obtained without reducing the flow rate of the refrigerating machine oil to the compressor.

Since only the suction tube 115, the oil return tube 119 and the discharge tube 120 are connected to the accumulator container 111, an accumulator having a simple appearance can be obtained. Twenty-second Modality A twenty-second embodiment has a structure such that the element for maintaining the liquid level in the first space comprises the cylinder and the refrigerant suction tube according to the sixth embodiment. Moreover, the first and second space are formed by a container, and the movement element is used to move the accumulated liquid in the second space for the first space according to the twenty-first embodiment. Now an accumulator according to this modality will be described. Figure 29 (a) is a vertical cross-sectional view showing the accumulator according to the twenty-second embodiment, and Figure 29 (b) is a cross-sectional view taken along the line XX shown in Figure 29 (to) . Referring to the drawings, the reference numeral 123 represents an accumulator container and 124 represents a division plate for vertically dividing the internal portion of the accumulator container 123. The reference numeral 125 repre sents a first space, 126 re-presents a second space, 127 represents an eduction tube, 128 represents a gas communication tube, 129 represents an oil return pipe, 130 represents a discharge pipe, 131 and 132 represent oil recovery pipes, 133 represents a refrigerant suction pipe. and 134 represents a cylinder. The height hl of the bottom surface in the first space 125, the height h2 from the bottom surface in the first space 125 to the refrigerant suction pipe 133 and the height h3 from the bottom surface in the first space 125 to the lower end of cylinder 134 satiefacen the ratio h3 < hl < h2. The upper end of the coolant eduction pipe 133 penetrates the partition plate 124 and allows it to communicate with the second space 126. When the liquid level (the oil level) in the coolant suction pipe 133 is in a range of h3 to h2, the refrigerant gas is introduced into the second space 126 through the refrigerant suction pipe 133. At this time, the cooling liquid has been introduced from the lower end of the cylinder 134 in an amount corresponding to the liquid level. When the liquid level (the oil level) becomes no less than h2, the liquid refrigerant is introduced into the second space 126 through the refrigerant suction tube 133. Aei, the liquid level in the first space 125 goes down. During the operation of the refrigeration and air conditioning circuit, the refrigerant gas flows from the first space 125 to the second space 126 through the gas communication tube 128. Therefore, a loss of pressure is present. Thus, the pressure in the first space 125 is greater than that of the second space 126. Therefore, the liquid refrigerant moved to the second space 126 is not regressed from the coolant eduction tube 133 to the first space 125. When the interrupter is interrupted the operation of the refrigeration and air conditioning circuit, the difference in the pressure between the inner portion of the first space 125 and that of the second space 126 is eliminated. In this case, the liquid refrigerant accumulated in the second space 126 recovers the first space 125 by the force of gravity from the coolant eduction tube 133. As noted above, the substantially constant liquid level (the oil level) of h2 is maintained in the first space 125. Therefore, the refrigerating machine oil can be made to exist adjacent to the height of the return pipe of the refrigerant. oil 129 so that the oil for refrigerating machine selectively returns to the purchaser. Still, the liquid refrigerant can accumulate in the second space 126. When it is used for refrigerating machine that has little solubility with the liquid refrigerant in the refrigeration and air conditioning circuit, the flow rate of the oil for refrigerating machine which flows from the oil return tube 129 haeta the compreeor can make it constant. As a result, you can avoid generating a defect in the compreeor. The movement element is structured in such a way that a plurality of oil recovery holes are formed in the vertical direction of the refrigerant eduction tube 133. Still, the refrigerant eduction tube 133 is arranged to be immersed in the portion of accumulation of liquid in the second space 126. The highest position of the oil recovery hole is to be adjacent to the highest liquid level in the second space 126. If the liquid level in the second room 126 exits in some The pore, reliably separated from the above liquid, can be recovered in the first space 125 by vertically providing the various oil recovery holes. The oil recovery tube 132 for establishing communication between the lower end of the oil recovery tube 131 and the suction tube 127 has an end that is allowed to project towards the inner portion of the suction tube 127 in, for example, some millimeters Similarly to the twenty-eighth embodiment, the recovery tubes 131 and 132 cause the refrigerating machine oil to be introduced into the oil recovery tube 131 through the oil recovery holes corresponding to the oil level even the oil for the oil recovery. refrigerated machine accumulated in the second space 126 is placed in any position. Thus, the liquid refrigerant is introduced into the oil recovery tube 131 through the oil recovery holes that face the liquid refrigerant. As a result of the ejection effect obtained attributable to the internal flow in the suction tube 127, the pressure at the forward end of the oil recovery tube 132 is made to be a negative pressure as compared to the surrounding static pressure. Thus the refrigerating machine oil and the liquid refrigerant introduced into the oil recovery tube 132 are sucked into the suction tube 127, and then recovered in the first space 125. As described above, the refrigerating machine oil introduced in the second space 126 ee can recover in the first space 125 even during the operation of the cooling and air conditioning circuit. As a result, the oil for refrigerating machine and the refrigerant liquid accumulated in the second space can efficiently recover the first space independent of the liquid level and even during the operation and interruption of the operation of the refrigeration and air conditioning circuit. Still, the oil for refrigerating machine ee can be recovered for the compressor through the oil return pipe 129.

Since only the suction tube 127, the oil return tube 129 and the discharge tube 130 are connected to the accumulator container 123, an accumulator having an overall appearance can be obtained. Twenty-third Modality A third order modality has an structure such as that of the first container 1 according to the second modality and the second container 2 according to the eleventh modality eetán formed by a container. An accumulator according to this embodiment will now be described. Figure 30 is a cross-section vieta showing the twenty-third modality. Referring to the drawing, reference numeral 135 represents an accumulator container and 136 repre- sents a partition plate for vertically dividing the interior portion of accumulator container 135. Reference numeral 137 repre- sents a first space, 138 repre- sents a second space, 139 depicts an eduction tube, 140 represents a gas communication tube, 141 represents an air duct tube, 142 represents a communication tube, 143 represents an oil return hole corresponding to the oil return tube and 144 repre- a tube of deecarga. The third and third embodiment has the structure such that the element for maintaining the liquid level in the first space comprises the air duct tube and the communication tube according to the first mode. Moreover, the first and second space are made through a container. In addition, the movement element for moving the accumulated liquid in the second space to the first space comprises the oil recovery tube according to the tenth modality. An accumulator according to this embodiment will now be described. Figure 30 (a) is a cross-sectional view showing the accumulator according to the twenty-third embodiment. Figure 30 (b) is a cross-sectional view taken along the X-X line. Referring to the drawings, reference numeral 135 represents an accumulator container and 136 represents a partition plate for vertically dividing the interior portion of accumulator container 135. Reference numeral 137 represents a first space, 138 represents a second space 139 represents a suction tube, 140 represents a gae communication tube, 141 represents an air duct tube, 142 represents a communication tube, 143 represents an oil return hole corresponding to the oil return tube, 144 represents a discharge tube and 145 and 146 represent oil recovery tubes. In this mode, the oil return hole 143 is formed in the surface of the discharge pipe 144 so that the discharge pipe 144 returns the refrigerant gas and the refrigerating machine oil to the refrigeration and air conditioning circuit. The height hl of the bottom surface in the first space 137 to the oil return hole 143, the height h2 of the bottom surface in the first space 137 to the communication tube 142 and the height h3 of the bottom surface in the first space 137 to the lower end of the air duct tube 141 satisfy the ratio h3 < hl < h2. Moreover, the lower end of the gas communication tube 140 penetrates the partition plate 124 to allow communication with the second space 138. When the liquid level (the oil level) in the first space 137 is in a range of h3 to h2, the gas refrigerant is introduced from the air duct tube 141 to the communication tube 142. Then, the refrigerant gas flows from the gas communication tube 140 to the second space 138. At this time, the refrigerant Liquid has been introduced from the lower end of the air duct tube 141 in an amount corresponding to the level of the liquid. When the level of the liquid (the oil level) has been raised to no less than h2, the liquid refrigerant is allowed to be trapped through the communication tube 142. Then, the liquid refrigerant is introduced into the second space 138 from the tube of gas communication 140, and then accumulates in the second space 138. As a result, the liquid level in the first space 137 is lowered.

As described above, the substantially constant liquid level (the oil level) of h2 is maintained in the first space 137. Therefore, the oil for refrigerating machine can be made to exist adjacent to the height of the return hole of the refrigerant. oil 143 so that the refrigerating machine oil returns selectively to the compressor. Moreover, the liquid refrigerant may accumulate in the second space 138. When oil is used for refrigerating machine which has poor solubility with the liquid refrigerant in the refrigeration and air conditioning circuit, the flow rate of the refrigerating machine oil which flows from the oil return hole 143 haeta the compressor ee can make it constant. As a result, the generation of a defect in the compressor can be avoided. The movement element is structured in such a way that a plurality of oil recovery holes are formed in the vertical direction of the oil recovery tube 145. Moreover, the oil recovery tube 145 is arranged in such a way that the pipe of The recovery of oil 145 is immersed in the liquid accumulation portion in the second space 138. The highest position of the oil recovery holes is made to be adjacent to the highest liquid level in the second 138 space. liquid level accumulated in the second space 138 is placed in any position, the oil for refrigerating machine, separated on the liquid can be returned to the first space 137. To achieve this, a plurality of oil recovery holes are formed in the direction vertical The oil recovery tube 146 for establishing communication between the lower end of the oil recovery tube 145 and the suction tube 139 has one end projecting towards the inner portion of the suction tube 139 several millimeters. The operations of oil recovery tubes 145 and 146 are the same as those in accordance with the first-in-force modality. If the refrigerating machine oil accumulated in the second space 138 is placed in any position, the refrigerating machine oil is introduced into the oil recovery tube 145 through the oil recovery hole corresponding to the oil level. Furthermore, the liquid refrigerant is introduced into the oil recovery tube 145 through the oil recovery holes facing the liquid refrigerant. As a result of the expelling effect exerted on the forward end of the oil recovery tube 146 obtained by the internal flow in the suction pipe 139, the pressure at the front end of the oil recovery tube makes it a negative pressure in the comparison with the surrounding eetática pressure. As a result, the refrigerating machine oil and the liquid refrigerant introduced into the oil recovery tube 146 are sucked into the suction tube 139, and then recovered in the first space 137. As described above, the refrigerating machine oil introduced into the second space 138 can be recovered in the first space 137 even during the operation of the refrigeration and air conditioning circuit. As noted above, the refrigerating machine oil accumulated in the second space can be efficiently recovered to the first space regardless of the level of the liquid even during operation or the interruption of the refrigeration and air conditioning circuit. Moreover, the refrigerating machine oil can be recovered for the compressor through the oil return hole 143 and the discharge pipe 144. As only the suction pipe 139 and the discharge pipe 144 are connected to the accumulator container 135. , you can get an accumulator that has a simple appearance. As described above, from the sixteenth to the thirteenth modes have the structure that a container forms the accumulator. However, another modification can be used as the method for realizing the structure by means of a container in such a way that the first to the fifteenth modality are combined with one another. In the present invention, the method is not limited to any of the modalities mentioned above. Another structure can be used to realize the first and the second space by means of a container to obtain an accumulator that has a simple structure and that allows an easy operation.

[EFFECT OF THE INVENTION] As described above, the structure according to the first aspect of the present invention has the first space within which a liquid and a gas that are fluid arranged to circulate in the refrigeration and air conditioning circuit is enter through the introduction element; the second space to introduce the gas from the first space by means of the gas passage element, discharge the gas to the refrigeration circuit and air conditioning by means of the discharge element and having the structure apt to accumulate the liquid, - the element to maintain the level of the liquid to prevent the level of the liquid introduced in the first space from reaching a level not lower than a predetermined height; the liquid passage element for moving the liquid from the first space to the second space when the level of the liquid has risen to a level no lower than a predetermined height; and the return element opened in the first space to a position lower than the previously determined height and arranged to discharge the accumulated liquid in the first space for the refrigeration and air conditioning circuit. Thus, an accumulator can be obtained which is apt to maintain the level of the liquid constitutively in the first space, restricting the amount of introduction of the liquid refrigerant to the compressor, obtaining a required amount of refrigerant machine oil in the compressor and improving the reliability . The structure according to the second aspect of the present invention is arranged in such a manner that the liquid passage element and the gae passage element according to the first aspect ee form within the gas discharge tube having open ends. in the gae portion of the first space and the other open ends in the second space and disks in the vertical direction through the gas portion and the liquid accumulation portion in the first space, and the element for maintaining the level of the liquid it has the communication portion that allows communicating with the gas pampered tube in the vertical direction in the first space at a predetermined height, the first passage to establish communication between the communication portion and the upper portion in the first space and the second passage to establish communication between the communication portion and the space in the first space in the inferred position ior to the previously determined height. As a result, an accumulator can be obtained which is capable of maintaining the liquid level substantially constant in the first space to restrict the amount of introduction of the liquid refrigerant to the compressor, obtain a required amount of refrigerant machine oil in the compressor and improve the reliability. The structure according to the third aspect of the present invention is arranged according to the first and second aspects and formed to further comprise the movement element for moving the accumulated liquid in the second space to the first space. Ae, ee can obtain an accumulator that is capable of returning to the refrigerating machine oil accumulated in the second space from the first space to the compressor to obtain the refrigerating machine oil required for the compressor. The structure according to the fourth aspect of the present invention is arranged according to the third aspect and is formed in such a way that the second space is formed above the first space, and the movement element is the communication element to establish the communication between the portion of liquid accumulation in the second space and the first space. As a result, you can obtain an accumulator that is able to return to the refrigerating machine oil accumulated in the second space from the first space to the compressor to obtain refrigerating machine oil for the compressor. The structure according to the fifth aspect of the present invention is arranged according to the third aspect and is formed in such a way that the movement element establishes the communication between the introduction element and the liquid accumulation portion in the second space by force of one or a plurality of connecting elements and the end of the connecting element adjacent to the introduction element is allowed to project towards the inner portion of the introduction element towards the inner surface so that the liquid accumulated in the second space is made follow the fluid when the fluid is introduced into the first space by the introduction element. A) Yes, ee can obtain an accumulator that is able to return the refrigerating machine oil accumulated in the second space from the first space to the compressor without interrupting the operation of the refrigeration and air conditioning circuit to obtain the refrigerating machine oil required by the compreeor The structure according to the sixth aspect of the present invention is arranged according to the third aspect and is formed in such a way that the movement element is composed of the liquid recovery element, arranged vertically in the liquid accumulation portion in the second space and arranged to be able to recover the liquid placed in different positions in the vertical direction and a connection element to establish the communication between the introduction element, the liquid recovery element, and the end of the adjacent connecting element The introduction element is allowed to project on the surface of the introduction element towards the inner portion so that the liquid accumulated in the second space is made to follow the fluid when the fluid is introduced into the first space by the insertion element. Thus, an accumulator can be obtained that is able to return the refrigerating machine oil accumulated in the second space from the first space to the compressor without having to interrupt the operation of the refrigeration and air conditioning circuit to obtain the refrigerating machine oil required by the refrigerant machine. the compressor. The structure according to the seventh aspect of the present invention is arranged according to the third aspect and is formed in such a way that the second space is disposed above the first space and the movement element consists of the third space formed in a intermediate between the second space and the first space, the first open / close valve between the first space and the third space and the second open / close valve placed between the second space and the third space, so that the first open / close valve is closed when the second open / close valve is open and the first open / close valve is open when the second open / close valve is closed in order to move the liquid accumulated in the second space to the open / close first space through the third space. Therefore, it is possible to obtain an accumulator which is able to return the refrigerating machine oil accumulated in the second space from the first space to the compressor without having to interrupt the operation of the cooling and air conditioning circuit to obtain the refrigerating machine oil. required by the compressor. The structure according to the eighth aspect of the present invention is die according to any of the first to the seventh aspect and the form in such a way that the liquid level stabilization element in the space is provided by either the first space or the second eepacio. Thus, an accumulator can be obtained which is able to stabilize the liquid level in each of the first space and the second space and effectively perform gas-liquid separation.

Claims (10)

1. CLAIMS 1. An accumulator for use in a refrigeration and air conditioning circuit, the accumulator comprises: a container element for defining a first and a second space; an introduction element for introducing, in the first space, liquid and a gas that are fluid diepueetoe to circulate in the refrigeration and air conditioning circuit; a gas paffer element for introducing the gas from the first space to the second space; a discharge element for discharging the gas from the second space to the refrigeration and air conditioning circuit while allowing the liquid to accumulate in the second space; a liquid level maintenance element to prevent the liquid from entering and accumulating in the first space having a level no less than a previously determined height; a liquid passage element for moving the liquid from the first space to the second space when the liquid in the first space has a level no lower than the previously determined height; and a return element, open in the first space and in a lower position than the previously determined height, to discharge the liquid accumulated in the first space in the refrigeration and air conditioning circuit. An accumulator according to claim 1, wherein the liquid passage element and the gas passage element include a common gas passage tube having: an open end in a gas portion of the first space, the another open end in the second space, and a disposed portion in a vertical direction through the gas portion and a liquid accumulation portion in the first space, and wherein the liquid level maintenance element includes: a portion of communication communicating with the portion of the gas passage tube at the previously determined height; a first passage for communication between the communication portion and an upper portion in the first space; and a second passage for communication between the communication portion and a space in the first space in a lower position than the previously determined height. 3. An accumulator according to claim 1 or 2, further comprising: a movement element for moving the liquid accumulated in the second space towards the first space. 4. An accumulator according to the claim 3, wherein: the second space is disposed above the first space, and the movement element includes communication elements for communication between the liquid accumulation portion in the second space and the first space. An accumulator according to claim 3, wherein: the movement element includes at least one connection means for communication between the introduction element and the liquid accumulation portion in the second space; and one end of the connecting element adjacent to the introduction element projects inwardly on the inner surface of the introduction element so that the liquid accumulated in the second space is followed by the fluid when the fluid is introduced into the first space by the introduction element. An accumulator according to claim 3, wherein the movement element includes: a liquid recovery element arranged vertically in the liquid accumulation portion in the second space and accommodated to be able to recover the liquid in different positions vertically, and a connecting element for communication between the introduction element and the liquid recovery element; and one end of the connecting element adjacent to the introduction element projects inwardly on the inner surface of the introduction element so that the liquid accumulated in the second space is made to follow the fluid when the fluid is introduced into the first space by means of the introduction element. An accumulator according to claim 3, wherein: the movement element includes: a liquid recovery element arranged vertically in the liquid accumulation portion in the second space and adapted to be able to recover the liquid in poeicionee vertically different, and a connecting element for communication between the introduction element and the liquid recovery element; and one end of the connecting element adjacent to the introduction element projects inwardly on the inner surface of the introduction element so that the liquid accumulated in the second space is made to follow the fluid when the fluid is introduced into the first space by means of the introduction element. 7. An accumulator according to claim 3, wherein: the second eepacio ee diepone above the first eepacio; and the movement element includes: a third space formed in an intermediate position between the second space and the first space, - a first valve for opening / closing a tank between the first space and the third space, - and a second valve for opening / closing / close dispueeta between the second eepacio and the third space; and the first open / close valve is closed when the second open / close valve is opened and the first open / close valve is opened when the second open / close valve is closed in order to move the liquid accumulated in the second space towards the first space through the third space. 8. An accumulator according to any one of claims 1 to 7, further comprising: a water level stabilizing element for stabilizing the liquid level in the space, the liquid level stabilizing element providing at least one of the first space and the second space 9. An accumulator according to claim 1, wherein the container element includes a first container that defines the first space in the element, a second container that defines the second space in the member, and the first and second containment are disposed separately. each . An accumulator according to claim 1, wherein the container element includes a single container defining the first and second spaces therein with a partition.