CN111936804B

CN111936804B - Air conditioner

Info

Publication number: CN111936804B
Application number: CN201880092035.9A
Authority: CN
Inventors: 津村涉子; 长房智之; 月居和英; 井柳友宏; 安部亮辅
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2018-04-13
Filing date: 2018-04-13
Publication date: 2022-02-15
Anticipated expiration: 2038-04-13
Also published as: CN111936804A; JP6972316B2; KR102408552B1; JPWO2019198228A1; WO2019198228A1; CZ2020511A3; KR20200118107A

Abstract

The air conditioner is provided with: an outdoor unit having a compressor and an outdoor heat exchanger, an indoor unit having an indoor heat exchanger, and an opening valve for guiding gas inside the compressor to the outside. The compressor, the outdoor heat exchanger, and the indoor heat exchanger are connected by refrigerant pipes to form a refrigerant circuit. The opening valve has a cylindrical portion and a plate-like closing portion, a 1 st end portion of the cylindrical portion is open, a 2 nd end portion of the cylindrical portion is closed by the closing portion, and the cylindrical portion is communicated with the compressor via the 1 st end portion. The opening valve is configured to form an opening at a boundary portion between the cylindrical portion and the closed portion or at the closed portion when the pressure inside the compressor reaches an opening pressure, the opening pressure being higher than a guaranteed pressure of the compressor set higher than a design pressure of the air conditioner and lower than a breakage pressure that is a pressure at which the compressor is broken.

Description

Air conditioner

Technical Field

The present invention relates to an air conditioner, and more particularly, to prevention of damage to a compressor.

Background

Conventionally, when a split type (separate) air conditioner is moved or disposed of, a forced cooling operation called evacuation is performed in which the refrigerant in the refrigerant circuit is recovered to the outdoor unit. If a large amount of air is mixed into the refrigerant circuit during evacuation, air compression occurs inside the compressor provided in the outdoor unit, and high-temperature and high-pressure air is mixed with the refrigerator oil. As a result, the pressure inside the compressor increases rapidly, and the casing of the compressor may be damaged.

Patent document 1 describes a structure in which a safety valve is attached to a hole communicating with a discharge chamber of a compressor and the safety valve is covered with a rupture plate. The safety valve is configured to be opened when a pressure greater than or equal to a predetermined pressure acts on the discharge chamber. The rupture plate is configured to rupture when operated at a pressure lower than the operating pressure of the safety valve. When an abnormality occurs in the operation of the compressor and the pressure in the discharge chamber of the compressor becomes a predetermined pressure or more, the safety valve opens and the rupture plate ruptures. As a result, the refrigerant in the discharge chamber is released to the atmosphere, and the pressure in the compressor is reduced, thereby preventing the compressor from being damaged by high pressure.

Patent document 1: japanese patent laid-open publication No. 2004-353578

The safety valve of patent document 1 uses a spring body, and a gas storage chamber is formed between the safety valve and a rupture plate. Therefore, in order to communicate the inside and outside of the compressor, the valve body must be pushed up against the urging force of the spring body. Therefore, the structure described in patent document 1 has a problem that it cannot cope with a rapid pressure rise that may occur during evacuation.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide an air conditioner in which a casing of a compressor is not damaged even if the pressure in the compressor rapidly rises.

The air conditioner of the invention comprises: the outdoor unit includes a compressor and an outdoor heat exchanger, an indoor unit including an indoor heat exchanger, and an opening valve for guiding gas inside the compressor to the outside, the compressor, the outdoor heat exchanger, and the indoor heat exchanger are connected by a refrigerant pipe to form a refrigerant circuit, the opening valve is configured to include a cylindrical portion and a plate-shaped closed portion, a 1 st end portion of the cylindrical portion is open, a 2 nd end portion of the cylindrical portion is closed, the cylindrical portion communicates with the compressor via the 1 st end portion, and an opening is formed at a boundary portion between the cylindrical portion and the closed portion or the closed portion when a pressure inside the compressor reaches an opening pressure, the opening pressure being higher than a guaranteed pressure of the compressor set to be higher than a design pressure of the air conditioner and lower than a breakage pressure at which the compressor is broken.

According to the air conditioner of the present invention, the 1 st end portion of the cylindrical portion of the opening valve is open, the cylindrical portion communicates with the compressor via the 1 st end portion, and the opening valve is opened when an opening pressure higher than a guaranteed pressure of the compressor and lower than a breakage pressure of the compressor is reached. Therefore, even if the pressure inside the compressor increases rapidly, the shell of the compressor can be prevented from being damaged.

Drawings

Fig. 1 is a refrigeration cycle diagram of an air conditioner according to embodiment 1 of the present invention.

Fig. 2 is a schematic view of a compressor of an air conditioner according to embodiment 1 of the present invention.

Fig. 3 is a diagram showing a configuration of an opening valve of an air conditioner according to embodiment 1 of the present invention.

Fig. 4 is a graph showing a change in pressure inside a compressor of an air conditioner according to embodiment 1 of the present invention.

Fig. 5 is a graph plotting the relationship between the rotation speed and the pressure increase rate of the compressor based on the experimental results shown in table 1.

Fig. 6 is a graph showing the relationship between the inner diameter of the cylindrical portion of the open valve and the pressure release rate based on the experimental results shown in table 2.

Fig. 7 is a graph showing the relationship between the ratio of the plate thickness of the closed portion to the inner diameter of the cylindrical portion in the open valve and the maximum pressure inside the compressor based on the experimental results shown in table 3.

Fig. 8 is a diagram showing another example of an opening valve of an air conditioner.

Fig. 9 is a diagram showing another example of an opening valve of an air conditioner.

Fig. 10 is a schematic view of a compressor of an air conditioner according to embodiment 2 of the present invention.

Fig. 11 is a refrigeration cycle diagram of an air conditioner according to embodiment 3 of the present invention.

Detailed Description

Next, an embodiment of an air conditioner according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below. In the following drawings, the size and shape of each component may be different from those of an actual apparatus.

Embodiment mode 1

Fig. 1 is a refrigeration cycle diagram of an air conditioner according to embodiment 1 of the present invention. The air conditioner 1 includes an outdoor unit 10 and indoor units 20. The outdoor unit 10 includes a compressor 11, a muffler 12, a four-way switching valve 13, an outdoor heat exchanger 14, a refrigerant pressure reducing device 15, a liquid-side closing valve 16, a gas-side closing valve 17, and an outdoor blower 18. The indoor unit 20 includes an indoor heat exchanger 21 and an indoor fan 22. The compressor 11, the muffler 12, the four-way switching valve 13, the outdoor heat exchanger 14, the refrigerant pressure reducing device 15, the liquid-side closing valve 16, the indoor heat exchanger 21, and the gas-side closing valve 17 are connected in order by the refrigerant pipe 30, and form a refrigerant circuit.

The compressor 11 compresses and discharges the sucked refrigerant. The compressor 11 changes the capacity of the compressor 11, that is, the amount of refrigerant delivered per unit time, by arbitrarily changing the operating frequency using, for example, an inverter circuit or the like. The muffler 12 is disposed on the discharge side of the compressor 11. The muffler 12 reduces pulsation of the refrigerant. The four-way switching valve 13 is a valve that switches the flow of the refrigerant between the cooling operation and the heating operation. Fig. 1 shows a refrigerant cycle during cooling operation. In fig. 1, a refrigerant circuit during heating operation is partially omitted.

The outdoor heat exchanger 14 performs heat exchange between the refrigerant and outdoor air. The outdoor heat exchanger 14 functions as an evaporator during the heating operation, and evaporates and gasifies the refrigerant. The outdoor heat exchanger 14 functions as a condenser during the cooling operation, and condenses and liquefies the refrigerant. The refrigerant decompression device 15 decompresses and expands the refrigerant. When the refrigerant decompression device 15 is configured by, for example, an electronic expansion valve, the opening degree of the refrigerant decompression device 15 is adjusted based on an instruction from a control device, not shown. The outdoor air heat-exchanged with the refrigerant in the outdoor heat exchanger 14 is sent to the outdoor heat exchanger 14 by the outdoor fan 18.

The indoor heat exchanger 21 performs heat exchange between air to be air-conditioned and the refrigerant. The indoor heat exchanger 21 functions as a condenser during the heating operation, and condenses and liquefies the refrigerant. The indoor heat exchanger 21 functions as an evaporator during the cooling operation, and evaporates and gasifies the refrigerant. The air that exchanges heat with the refrigerant in the indoor heat exchanger 21 is sent to the indoor heat exchanger 21 by the indoor air-sending device 22.

Fig. 2 is a schematic view of a compressor of an air conditioner according to embodiment 1 of the present invention. The compressor 11 has a housing 110 and an opening valve 40. The housing 110 has a top surface portion 110A and a body portion 110B. The refrigerant pipe 30 is connected to the top surface portion 110A. The opening valve 40 is a member for guiding gas inside the compressor 11 to the outside. The open valve 40 is provided as a separate component from the refrigerant pipe 30 in an end plate of the top surface portion 110A.

Fig. 3 is a diagram showing a configuration of an opening valve of an air conditioner according to embodiment 1 of the present invention. The opening valve 40 has a cylindrical portion 41 and a plate-like closing portion 42, and is cylindrical as a whole. Fig. 3 shows a vertical cross section of the open valve 40 after cutting the axial center of the cylindrical portion 41. The 1 st end 41A of the cylindrical portion 41 is open, and the 2 nd end 41B of the cylindrical portion 41 is closed by the closing portion 42. The closing portion 42 has a flat plate shape.

As shown in fig. 2, the opening valve 40 is provided in the compressor 11 such that the 1 st end portion 41A of the cylindrical portion 41 opens toward the inside of the compressor 11 and the 2 nd end portion 41B opens toward the outside of the compressor 11. The cylindrical portion 41 communicates with the compressor 11 via the 1 st end portion 41A. With this configuration, the gas in the compressor 11 flows into the cylindrical portion 41.

Fig. 4 is a graph showing a change in pressure inside a compressor of an air conditioner according to embodiment 1 of the present invention. The function of the opening valve 40 will be explained with reference to fig. 4. The graph of fig. 4 shows the pressure P inside the compressor 11 on the vertical axis and the time T on the horizontal axis. The pressure P is in MPa and the time T is in sec, i.e. seconds. Pcomp is the design pressure of the air conditioner 1. P1max is the guaranteed pressure of the compressor 11. The guaranteed pressure P1max of the compressor 11 is about 3 times the design pressure Pcomp of the air conditioner 1. The compressor 11 is designed to ensure a guaranteed pressure P1 max. That is, if the pressure applied to the inside of the compressor 11 is lower than the guaranteed pressure P1max, the normal operation of the compressor 11 can be guaranteed. P2max is the breakage pressure of the compressor 11. The breakage pressure P2max of the compressor 11 is a pressure at which the compressor 11 is broken, and has a tolerance on the high pressure side with respect to the guaranteed pressure P1 max. That is, if a pressure equal to or higher than the breakage pressure P2max is applied to the inside of the compressor 11, the compressor 11 may be broken and may not normally operate.

During the evacuation, in order to recover the refrigerant of the indoor unit 20 shown in fig. 1 to the outdoor unit 10, the liquid-side closing valve 16 is fully closed, and the gas-side closing valve 17 is fully opened, thereby performing the forced refrigerant operation. At this time, for example, if the cooling operation is performed while the gas side shutoff valve 17 is fully opened in a state where the outdoor unit 10 and the indoor unit 20 are shut off, a large amount of air is mixed into the refrigerant circuit. As a result, air compression occurs inside the compressor 11, and the pressure P of the compressor 11 rapidly rises to exceed the breakage pressure P2max, and the compressor 11 may be broken.

A solid line L1 in fig. 4 shows a state in which a large amount of air is mixed in the refrigerant circuit during evacuation execution of the air conditioner 1, and the pressure P of the compressor 11 rapidly rises from a state lower than the design pressure Pcomp to exceed the design pressure Pcomp and further exceed the guaranteed pressure P1 max. In this case, if the high-pressure gas in the compressor 11 is not discharged to the outside of the compressor 11, the pressure P of the compressor 11 continues to rapidly increase to exceed the breakage pressure P2max as indicated by a thin broken line L2.

In view of this, embodiment 1 is configured such that: when the pressure P of the compressor 11 rises rapidly, the high-pressure gas inside the compressor 11 is discharged through the opening valve 40. The opening valve 40 is configured to start opening when an opening pressure Pp that is set to a value higher than the guaranteed pressure P1max of the compressor 11 and lower than the breakage pressure P2max of the compressor 11 is applied. That is, if the pressure at which the gas flowing into the cylindrical portion 41 presses the closing portion 42 exceeds the guaranteed pressure P1max and reaches the opening pressure Pp due to the rise of the pressure in the compressor 11, an opening is formed at the boundary portion between the cylindrical portion 41 and the closing portion 42 or the closing portion 42 itself. The cylindrical portion 41 serves as a discharge flow path for guiding the gas inside the compressor 11 to the outside of the compressor 11.

The opening valve 40 is configured to form a relief flow path for guiding the gas inside the compressor 11 to the outside of the compressor 11 faster than the pressure P of the compressor 11 from the excess securing pressure P1max to the breakage pressure P2 max. In the example shown in fig. 4, the time from when the pressure P of the compressor 11 exceeds the guaranteed pressure P1max to when the breakage pressure P2max is reached is t2 seconds to t1 seconds. In this case, in embodiment 1, the time from when the open valve 40 starts to open to when the cylindrical portion 41 functions as the release flow path is configured to be shorter than t2 seconds to t1 seconds. With this configuration, the pressure P of the compressor 11, which has abruptly increased and exceeded the guaranteed pressure P1max, decreases without reaching the breakage pressure P2max, as indicated by a thick broken line L3 in fig. 4.

In embodiment 1, as shown in fig. 3, the opening valve 40 is configured by the cylindrical portion 41 and the closing portion 42, and the 1 st end portion 41A of the cylindrical portion 41 communicates with the compressor 11. Here, the inner diameter of the cylindrical portion 41 of the open valve 40 and the plate thickness of the closing portion 42 will be described. Table 1 is a table showing the relationship between the rotation speed and the pressure increase speed of the compressor 11 in the case of using the compressor 11 having the casing 110 having the main body 110B with an inner diameter of 107mm and a plate thickness of 2.6 mm. Fig. 5 is a graph plotting the relationship between the rotation speed and the pressure increase speed of the compressor 11 based on the experimental results shown in table 1. As shown in Table 1 and FIG. 5, the pressure increase rate was about 200MPa/sec at 60rps, which is a general rotational speed of the compressor. In order to release the pressure in the compressor 11 without damaging the casing of the compressor 11, the pressure release rate must exceed the pressure rise rate.

[ Table 1]

Table 2 is a table showing the relationship between the inner diameter of the open valve 40 and the pressure release rate of the compressor 11 in the case of performing an experiment using the compressor 11 having the casing 110 of which the inner diameter of the body portion 110B is 107mm and the plate thickness is 2.6mm, and changing the inner diameter of the cylindrical portion 41 of the open valve 40. Fig. 6 is a graph showing the relationship between the inner diameter of the cylindrical portion 41 of the open valve 40 and the pressure release rate based on the experimental results shown in table 2. In the graph of fig. 6, the vertical axis represents the pressure release rate, and the horizontal axis represents the inner diameter of the cylindrical portion 41.

[ Table 2]

Here, as shown in fig. 6, when the inner diameter of the cylindrical portion 41 is 10mm or more, the pressure release rate tends to exceed 200 MPa/sec. Therefore, if the inner diameter of the cylindrical portion 41 is set to be about one tenth or more of the inner diameter of the main body portion 110B, the pressure release rate exceeds 200MPa/sec, and the pressure increase rate can be exceeded. On the other hand, the initial energy of the jet flow when the casing of the compressor 11 or the open valve 40 is damaged by the internal pressure is proportional to the length of the crack generated in the damaged portion of the casing of the compressor 11 or the open valve 40 at the initial stage of the damage if the internal pressure is the same. For example, assuming that a crack is straightly generated in the closing portion 42 of the open valve 40, the ratio of the damage of the casing of the compressor 11 to the initial energy caused by the release of the open valve 40 is the crack length generated in the casing of the compressor 11 due to the damage of the casing of the compressor 11: diameter of the opening valve 40. That is, the smaller the diameter of the opening valve 40 is, the more energy can be reduced at the time of pressure release. Based on these experimental results and examination, the inner diameter of the cylindrical portion 41 in embodiment 1 is set to be about one-tenth or more of the inner diameter of the body portion 110B of the casing 110 of the compressor 11 in fig. 2. More preferably, the inner diameter of the cylindrical portion 41 is equal to or more than one tenth of the inner diameter of the main body portion 110B of the casing 110 of the compressor 11, and the upper limit is set according to the allowable energy for pressure release.

Table 3 shows the relationship between the inner diameters of the closing portion 42 of the open valve 40 and the maximum pressure inside the compressor 11 in the case where the above-described compressor 11 was used and an experiment was performed by changing the plate thickness of the closing portion 42 of the open valve 40 and the inner diameter of the cylindrical portion 41. Fig. 7 is a graph showing the relationship between the ratio of the plate thickness of the closing portion 42 to the inner diameter of the cylindrical portion 41 in the open valve 40 and the maximum pressure inside the compressor 11 based on the experimental results shown in table 3. In the graph of fig. 7, the vertical axis represents the maximum pressure inside the compressor 11, and the horizontal axis represents the ratio of the plate thickness of the closing portion 42 to the inner diameter of the cylindrical portion 41.

[ Table 3]

Based on the experimental result, the content of the plate thickness of the closing portion 42 of the open valve 40 in embodiment 1 is set to about one tenth of the plate thickness of the shell 110 of the compressor 11 shown in fig. 2. More preferably, the plate thickness of the closing portion 42 is not less than one tenth of the plate thickness of the casing 110 of the compressor 11, and the upper limit is set according to the maximum pressure determined by the ratio to the inner diameter of the cylindrical portion 41. The plate thickness of the cylindrical portion 41 is larger than that of the closing portion 42. With the above configuration, the above-described function of the opening valve 40 can be realized.

According to embodiment 1, the opening valve 40 is closed by the closing portion 42 in a state where the pressure of the compressor 11 is lower than the guaranteed pressure P1max, and the opening valve 40 is opened when the pressure of the compressor 11 exceeds the guaranteed pressure P1max and reaches the opening pressure Pp. Then, the relief flow path is secured until the pressure of the compressor 11 reaches the breakage pressure P2 max. Therefore, the damage of the compressor 11 can be prevented when the pressure inside the compressor 11 rises sharply without affecting the functions and performance of the normal cooling operation and heating operation of the air conditioner 1. In particular, even when the rate of increase in the pressure P of the compressor 11 is higher than the rate of propagation of the high-pressure gas to the components of the refrigerant circuit other than the compressor 11, breakage of the casing 110 of the compressor 11 can be prevented.

Since the plate thickness of the cylindrical portion 41 of the open valve 40 is larger than the plate thickness of the closing portion 42, the shape of the cylindrical portion 41 as the relief flow path can be maintained after the open valve 40 is opened in response to a rapid pressure rise inside the compressor 11.

It is also conceivable to provide the air conditioner 1 with a temperature sensor or a pressure sensor and control the stop of the operation of the compressor 11 based on the detection results of these sensors. However, such control cannot cope with the occurrence of a phenomenon that the compressor 11 is deviated from a predetermined value set as a criterion for determining the operation stop or the pressure rise faster than the reaction speed of the sensor, and the compressor 11 may be damaged. In contrast, in embodiment 1, the opening pressure Pp of the opening valve 40 is set to a value greater than the guaranteed pressure P1max and less than the breakage pressure P2max, and the relief flow path is formed faster than the relief pressure P2max is reached after the guaranteed pressure P1max is exceeded. Therefore, according to embodiment 1, a rapid pressure rise in the compressor 11 can be coped with, and damage to the compressor 11 can be prevented.

In addition, according to embodiment 1, the plate thickness of the cylindrical portion 41 is larger than the plate thickness of the closing portion 42. Therefore, the opening is formed at the boundary between the closing portion 42 and the cylindrical portion 41 or the closing portion 42, and the shape of the cylindrical portion 41 serving as the release flow path can be maintained when the high-pressure gas is discharged to the outside of the compressor 11.

The shape of the closing portion 42 of the opening valve 40 is not limited to the shape shown in fig. 3. Fig. 8 and 9 are views showing other examples of the opening valve of the air conditioner. The opening valve 50 shown in fig. 8 has a cylindrical portion 51 and a closing portion 52. The 1 st end 51A of the cylindrical portion 51 is open, and the 2 nd end 51B is closed by the closing portion 52. The closing portion 52 is formed to be curved in a convex shape toward the inside of the cylindrical portion 51. In the example of fig. 8, the inner diameter of the cylindrical portion 51 is also set to about one tenth of the inner diameter of the main body portion 110B of the casing 110 of the compressor 11 shown in fig. 2, and the plate thickness of the closed portion 52 is set to about one tenth of the plate thickness of the casing 110 of the compressor 11 shown in fig. 2. More preferably, the inner diameter of the cylindrical portion 51 is set to one tenth or more of the inner diameter of the main body portion 110B of the casing 110 of the compressor 11, and the plate thickness of the closing portion 52 is set to one tenth or more of the plate thickness of the casing 110 of the compressor 11. The plate thickness of the cylindrical portion 51 is larger than that of the closing portion 52.

The opening valve 60 shown in fig. 9 has a cylindrical portion 61 and a closing portion 62. The 1 st end 61A of the cylindrical portion 61 is open, and the 2 nd end 61B is closed by the closing portion 62. The closing portion 62 is formed in a convex shape curved toward the outside of the cylindrical portion 61. In the example of fig. 9, the inner diameter of the cylindrical portion 61 is also set to about one tenth of the inner diameter of the main body portion 110B of the casing 110 of the compressor 11 shown in fig. 2, and the plate thickness of the closed portion 62 is set to about one tenth of the plate thickness of the casing 110 of the compressor 11 shown in fig. 2. More preferably, the inner diameter of the cylindrical portion 61 is set to one tenth or more of the inner diameter of the main body portion 110B of the casing 110 of the compressor 11, and the plate thickness of the closing portion 62 is set to one tenth or more of the plate thickness of the casing 110 of the compressor 11. The cylindrical portion 61 has a larger plate thickness than the closing portion 62.

Embodiment mode 2

Fig. 10 is a schematic view of a compressor of an air conditioner according to embodiment 2 of the present invention. In fig. 10, the same components as those of the compressor 11 according to embodiment 1 are denoted by the same reference numerals. As shown in fig. 10, the opening valve 40 is a member separate from the refrigerant pipe 30, and is provided on a side surface of the main body portion 110B of the compressor 11, and the 1 st end portion 41A of the cylindrical portion 41 communicates with the inside of the compressor 11. The open valve 40 is disposed at a position higher than the oil level of the refrigerating machine oil stored in the lower portion of the compressor 11 in the vertical direction of the body portion 110B. According to embodiment 2, the same effects as those of embodiment 1 described above can be obtained.

In embodiment 2, instead of the open valve 40, the open valve 50 shown in fig. 8 or the open valve 60 shown in fig. 9 may be provided on the side surface of the main body 110B of the compressor 11.

Embodiment 3

Fig. 11 is a refrigeration cycle diagram of an air conditioner according to embodiment 3 of the present invention. In fig. 11, the same components as those of the air conditioner 1 according to embodiment 1 are denoted by the same reference numerals. The high-pressure region 70 is a region connecting the compressor 11 and the outdoor heat exchanger 14, and is a region into which high-pressure gas discharged from the compressor 11 flows. In embodiment 3, in the range of the high-pressure region 70, the same opening valve 40 as described in embodiment 1 or 2 is provided in the refrigerant pipe 30 via the branch pipe 80. The branch pipe 80 is a branch pipe branching in 3 directions. To the branch pipe 80, a pipe connected to the discharge side of the compressor 11, a pipe connected to the muffler 12, and the 1 st end 41A of the open valve 40 shown in fig. 3 are connected. Therefore, the cylindrical portion 41 communicates with the compressor 11 via the 1 st end portion 41A, as in embodiments 1 and 2 described above. With this configuration, a discharge flow path for discharging high-pressure gas to the outside of the refrigerant circuit of the air conditioner 1 can be ensured.

The high-pressure region 70 includes a muffler 12 and a four-way switching valve 13, and the pressure in the high-pressure region 70 increases unevenly when the gas refrigerant discharged from the compressor 11 flows into the high-pressure region 70. Therefore, in order to prevent the pressure in the compressor 11 from exceeding the guaranteed pressure P1max before the pressure at the location where the opening valve 40 is provided reaches the opening pressure Pp, the location where the opening valve 40 is provided in the refrigerant pipe 30 must be adjusted based on the flow rate of the refrigerant and the distance from the discharge port of the compressor 11.

On the other hand, as shown in fig. 11, there is a case where the muffler 12 is included in a high-pressure region 70 from the compressor 11 to the outdoor heat exchanger 14. The muffler 12 is a component that is disposed closest to the compressor 11 among components located downstream of the compressor 11 in the refrigerant circuit during the cooling operation of the air conditioner 1. In this case, when the high-pressure gas flows into the high-pressure region 70 during the forced cooling operation by evacuation, the muffler 12 may be damaged. In view of this, in embodiment 3, the opening valve 40 is provided in the refrigerant pipe 30 through the branch pipe 80 in the pipe connecting the compressor 11 and the muffler 12. That is, when the evacuation is performed, the opening valve 40 is disposed at a position upstream of the muffler 12 in the refrigerant circuit.

According to embodiment 3, the refrigerant pipe 30 forming the refrigerant circuit is provided with the open valve 40. Therefore, the conventional configuration of the compressor 11 is not changed, and the compressor 11 can be prevented from being damaged even if a rapid pressure rise occurs during evacuation.

Further, according to embodiment 3, when the evacuation is performed, the opening valve 40 is disposed at a position upstream of the muffler 12 in the refrigerant circuit. Therefore, even if a sudden rise occurs during evacuation, not only the damage of the compressor 11 but also the damage of the muffler 12 can be prevented.

In embodiment 3, instead of the open valve 40, the open valve 50 of fig. 8 or the open valve 60 of fig. 9 may be attached to the branch pipe 80.

The branch pipe 80 may be a branch pipe that branches in 3 or more directions, and one of the branched pipes may be provided with the open valve 40.

Description of the reference numerals

1 … air conditioner; 10 … outdoor unit; 11 … compressor; 12 … silencer; 13 … four-way switching valve; 14 … outdoor heat exchanger; 15 … refrigerant pressure reduction device; 16 … liquid side closing valve; 17 … gas side closing valve; 18 … outdoor blower; 20 … indoor unit; 21 … indoor heat exchanger; 22 … indoor blower; 30 … refrigerant piping; a 40 … open valve; 41 … cylindrical part; 41a … end 1; 41B … end No. 2; a 42 … closure; a 50 … open valve; 51 … cylindrical part; 51A … end 1; 51B … end 2; 52 … closure; 60 … open valve; 61 … cylindrical part; 61A … end 1; 61B … end 2; a 62 … closure; 70 … high pressure region; 80 … branch pipes; 110 … shell; 110a … top face; 110B … body portion; p … pressure; p1max … ensures pressure; p2max … failure pressure; pp … opening pressure.

Claims

1. An air conditioner is provided with: an outdoor unit having a compressor and an outdoor heat exchanger, an indoor unit having an indoor heat exchanger, and an opening valve for guiding gas inside the compressor to the outside, the compressor, the outdoor heat exchanger, and the indoor heat exchanger being connected by a refrigerant pipe to form a refrigerant circuit, the air conditioner being characterized in that,

the opening valve is configured to:

a plate-like closing portion having a cylindrical portion with a 1 st end portion opened and a 2 nd end portion closed by the closing portion, the cylindrical portion communicating with the compressor via the 1 st end portion,

when the pressure in the compressor reaches an opening pressure, an opening is formed in a boundary portion between the cylindrical portion and the closed portion or the closed portion, the opening pressure being higher than a guaranteed pressure of the compressor set higher than a design pressure of the air conditioner and lower than a breakage pressure that is a pressure at which the compressor is broken,

the opening valve is arranged on the shell of the compressor,

the inner diameter of the cylindrical portion is one tenth or more of the inner diameter of the main body of the casing of the compressor, and the plate thickness of the closed portion is one tenth or more of the plate thickness of the casing of the compressor.

2. An air conditioner is provided with: an outdoor unit having a compressor and an outdoor heat exchanger, an indoor unit having an indoor heat exchanger, and an opening valve for guiding gas inside the compressor to the outside, the compressor, the outdoor heat exchanger, and the indoor heat exchanger being connected by a refrigerant pipe to form a refrigerant circuit, the air conditioner being characterized in that,

the opening valve is configured to:

the opening valve is arranged on the shell of the compressor,

the inner diameter of the cylindrical portion is one tenth or more of the inner diameter of the main body of the casing of the compressor, the plate thickness of the closing portion is one tenth or more of the plate thickness of the casing of the compressor,

the plate thickness of the cylindrical portion is larger than the plate thickness of the closing portion.