US2094875A - Expansion valve - Google Patents

Description

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EXPANSION VALVE Filed June 22, 1953 .2 5 MM 6 q M 1 WWW H M 2 z d fl M f .v a 7 W.

6 Q mm M M l 6 w a a m a 0 k 9 4 a 4 2 A z z w i w w iww Patented Oct. 5, 1937 "UNITED STATES,

PATENT OFFICE Claims.

able of being easily assembled in accurate relation to each other; to provide a valve which permits accurate and positive seating of the valve element; to provide an expansion valve embodying but a. single spring; to provide a valve struc ture having a floating valve or novel construction; to provide a valve structure having a full floating valve positively operated in both directions of movement; to provide an expansion valve in'which a full floating valve is connected to the pressure operated member thereof for positive inter-related movement; to provide a'valve of the type described having a full floating valve element positively movable vertically in opposite directions; andto provide an expansion valve having novel means for positively placing it in open position.

Other objects include the provision of a novel form of needle valve and connection with its operating' member, insuring perfect sealing of the valve at all times.

Further objects include the provision of a novel means for operating an expansion valve; the provision of a novel thermostatically controlled expansion valve; the provision of a novel connection between a thermostatically operated element and an expansion valve whereby the absorption of heat in the expansion valve will not affect the operation of .the thermostatic device; and the provision of'a thermostatically operated expansion valve having a novel form of connection between the thermostatic element and the valve proper permitting ease and accuracy of adjustmerit thereof. g

The above being among the objects of the present invention, the same consists in certain novel features of construction and combination of parts to be hereinafter described with reference to the accompanying drawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illustrates suitable embodiments. of the present invention and in which like numerals refer to like parts throughout the several different views,

(01. sir-2s) Fig. 1 is a vertical sectional view taken centrally through an expansion valve.

Fig. 2 is a vertical sectional view taken on the line 22 of Fig. 1.

Fig. 3 is -a fragmentary horizontal sectional 5 view taken on the line 33 of Fig. 1.

Fig. 4' is a horizontal sectional view taken on the line 4-4 of Fig. 1. I

Fig. 5 is a fragmentary, partially sectioned, partially broken, enlarged view showing with 10 greater clearness the construction of the connection between the valve proper and the member to which it is directly connected in the expansio valve shown in the previous. figures. 4

Fig. 6 is a view similar to Fig. 1 but showing 15.

the construction therein modified for operation by a thermostatic element.

As is well understood in the art, expansion valves are used in connection with refrigerating apparatus for controlling the flow of liquid re- 20 frigerant from the high pressure sideof the system to the low pressure side of the system. Such valves are controlled in a variety of different ways such, for instance, as by the pressure in the low side of the system, the temperature of the evaporator ,or the space which the evaporator cools, and in many cases by a float. One of the principal features of the present invention is in the construction of a valve itself which is applicable for use in connection with any of the above types of expansion valves or apparatus but, for the purpose of illustration only, the invention is herein illustrated in connection with an expansion valve of the pressure operated type and one of the thermostatically operated type, the application of the. valve itself to these structures involving further novel features constituting additional features of the present invention.

It is also well understood in the art that in connection with such valves, except for the float 40 control type, it is necessarygto have a movable wall of some suitable type to serve either as a pressure responsive element, or as a seal, or both, and while in the broader aspects of the present invention such movable wall may take the form of a bellows, a diaphragm or a piston, the former is shown as being preferred by way of illustra tion, although in some of the narrower phases of the present invention as will hereinafter be specifically pointed out and claimed, the bellows forms a part of a new and novel combination. Referring now to the drawing and particularly to Figs. 1 to 5 inclusive, an expansion valve is shown 'as including a casing I0 through which refrigerant is adapted'to flow as controlled'by the mechanism enclosed therein. The liquid refrigerant is adapted -to be introduced into the casing, as best illustrated in Fig. 4, through a connection member l2 threaded into a passage l4 formed in the casing III, a screen l6 of cylindrical formation and having a closed end (not shown) being suitably associated with the connection member l2 and projecting within the passage in spaced relation to the walls thereof so as to filter the refrigerant flowing to the valve and remove foreign material therefrom. The passage I4 is connected by a cross passage l8 with the lower end of a vertically extending passage alignment with the passage 20 is provided with close but normally spaced relation with respect a a threaded opening 26 normally closed by the plug 28 and through which opening the plug 22 and other parts of the valve structure may be inserted or removed. The plug 28 is provided with a recess 30 centrally disposed in its lower face, the purpose of which will be later disclosed.

The right hand end of the casing l is originally formed fully open and this open end is closed .by a bellows 32 having a head 34, and an open,

end which is sealed to a ring 36, the periphery of the ring being received against a shoulder 38 formed at the open end of the casing I0 and to which the ring 36 is suitably sealed as by solder. A cap 481s screwed onto the open end of the casing l0 over the openend of the bellows 32 and is provided with a central boss 42 axially aligned with the bellows 32. This boss is provided with a central axial opening in which is threadably received a headed bolt 44, the head of which projects into the bellows 32 and into relatively to the head 34 thereof. A cup member 46 is positioned within the bellows 32 and its bottom is soldered or otherwise fixed to the head 34. The open end of the cup 46 which extends to a point adjacent the open end of the bellows 32 is inwardly turned at its open end to form an annular flange 48 within which is removably received a split ring or washer 58 which serves as a seat for a conical coil spring 52 constantly maintained under compression between the ring 58 and the head of the bolt 44. By threading the screw inwardly or outwardly in the b05512 it will be apparent that the tension of the spring 52 acting to.collapse the bellows 32 may be varied, and consequently the amount of suction within the casing ll] necessary to expand the bellows 32 a given amount may be correspondingly varied. ,Preferably the exterior surfaceof the boss is threaded and receives thereon a smaller cap member 54 which maybe sealed to the cap 4|] through the employment of a suitable gasketsuch as 56.

Pivotally mounted within the casing between twp cone pointed pins 58 threaded through opposite walls of the casing l 8 is a bell crank 60 one arm 62 of which extends to the left as viewed in the drawing in a generally horizontal direction and the other arm 64 of which extends in a generally downwardly direction and is provided with a partially cylindrically formed end 66. The lengths of the arms 62 and 84 may, of course, be varied in their respective lengths as necessity or desires dictate. The end 66 is relatively closely received in a vertically extending rectangular opening provided in a bracket 18 which is soldered or otherwise suitably secured to the outer surface of the head 34 of the bellows 32, this connection being such as to permit rectilinear movement of the end of the bellows 32 and the bracket 10. while causing corresponding positive pivotal movement of the bell crank 68 in either direction.

The free end of the arm 62 of the bell crank 60 is provided with a relatively large vertically disposed opening 12 in axial alignment with the aperture in the plug 22 when the arm 62 is in horizontal position and threadably received in the opening 12 is a collar or ring member 14. Now referring to Fig. 5 in which this portion of the apparatus is shown in greater detail, it will be'noted that the collar I4 is provided with a bore 16 which is of smallest diameter at a point approximately midway its length and flares outwardly in both directions therefrom. The collar 14 is also provided with a transverse opening 18 at its. point of minimum internal diameter in which is received a pin 80. A valve or valve element 82 of the needle type is relatively closely received in the bore 16 at its point of minimum diameter and depends vertically therefrom, its pointed end 84 being received within the aperture 23' of the plug 22 and cooperating therewith to control the flow of fluid through the plug 22 into the casing I0. At the point where the valve element 82 projects through the collar 14 it is provided with a, transverse opening 86 in which the pin 88 is relatively closely received. The opening 86, in a manner similar to the bore 16, is of minimum diameter adjacent the midpoint of its length and flares outwardly in either diree tion therefrom, the walls of the opening 86 at the point of minimum diameter thereof relatively closely receiving-the pin 80. As will be apparent,

with this construction the valve element 82 is so supported relative to the arm 62 of the bell crank 60 that the poirt 84 of the valve element is allowed a limited amount of free floating movement in all directions except axially and consequently the point 84 is always capable of freely moving so as to properly accommodate itself to its seat in the plug 22.

'As will be noted, the upper end of the valve element 82 projects upwardly beyond .the upper end of the collar 14 and is provided ample clearance for its movement in the opening 30 in the plug 28. The upper face of the collar 14-, which is of greater diameter than the opening 30, is positioned in normally adjacent but spaced relation with respect to the lower face of the plug 28, and the spacing between these parts is such as to permit contact of the collar 14 with the cap .28 for.the purpose of limiting excessive expansive movement of the bellows 32 should the occasion arise, and thus prevent possible rupture of the bellows from such cause. Likewise, engagement of the valve element 82 with the plug 22 limits movement of the bellows in the opposite direction.

The construction of the valve element 82 and its supporting mechanism is of particular importance for the reason that when properlyvconstructed and assembled it provides a positively operated valve that is alway's positive in its seating and free of any sticking tendency. This is of utmost importance in connection with refrigerating mechanism as the lack of'a proper seat for the valve element in expansion valves is one of passage and these openings may then be tapped. the plug 22 inserted in place, and then the bellcrank 60 may be introduced through the opening 26 and the pins 58 threaded through the casing and'into a position to engage the bell crank 60.

A suitable locating tool (not shown) may now be threaded through the opening 12 in the arm 52 of the bell crank 60 and located'in the aperture 23 of the plug 22. The pins 58 may then be threaded either in and out until it is apparent that the locating tool is properly located in the aperture 23 and the pins 58 exert the proper pressure in their bearings in the bell crank 60 without interfering with the proper free pivotal movement thereof. Solder, such as 88, may then be applied to the casing I8 over the ends of the pins 58 to seal the casing from possible leakage at this point and to lock the pins in adjusted position. threaded inwardly until its head contacts the head 34 of the bellows 32 thus positioning the bell crank 60 in a definite location. The locating tool 3 may now be removed from the opening 12 and a suitable bushing may now be inserted in the opening 12 and employed for guiding a suitable tool for forming a shallow seat for the valve element 82 at the upper margin of the aperture 23 in the plug 22, and aftersuch tool and bushing is removed the collar 14 may be slipped over the valve element 82, the pin88 inserted in place and this assemblage threaded into the opening 12 in the arm 62 to its final position.

After this mechanism has been located in the manner described and the screw 44 backed off, it will be apparent that, because of the freedom of the universal movement of the valve. element 82 in the arm 62 of the bell crank, and particularly in view of the fact that the valve element is pendant, or positioned with its axis vertically and hanging from the pin 88, the coned end 84 of the valve element 82 will always find its proper seat upon closing movement of the valve. This is particularly true in view of the fact that the bell crank 60 will always be in the same position when the valve is moved to closed position and further due to the fact that the valve element 82 will seldom be lifted from its seat a distance greater than .010 of an inch during operation'of thevalve.

The operation of the above described valve will of course be apparent to those skilled in the art and briefly may be stated as follows: When the pressure on the low side of the system drops below a predetermined point, which may be variably controlled by manipulation of the screw 44 as previously described, the length of thebellows 32 will be increased, the head 34 of the bellows moving to the left as viewedin the drawing. Movement of the head 34 will cause an equal and positive movement of the bracket Illv which in turn will cause an equal and positive movement of the end 66, of the bell crank 60, causing the bell crank to pivot about its pivotal axis in a clockwise direction as viewed in the figures. 'lhts movement of At this point the screw 44 may be the bell crank will positively cause the free end of the arm 62 thereof to move upwardly and in moving upwardly will positively lift the valve element 82 and retract the end 84 thereof partially from the aperture 23 in the plug 22 and will 5 thus permit liquid refrigerant to flow into the casing through the aperture 23 and out of the casing through the passage 24 into the low pressure side of the system. As soon as the pressure'in the low pressure side of the system increases sufficiently to permit the spring 52 to contract the bellows 32 to such an extent as to move the valve element 82 again to closed position, the flow of liquid refrigerant into and out of the casing I 0' will be discontinued. Furthermore, rise in pressure on the low side of the system including the interior of the casing 10, will act on the bellows 32 to additionally force the valve point 84 against its seat. It is to be noted that during opening movement of the valve, the valve element 82 is positively moved toward opened position and,.likewise, during closing movement of the valve the valve element 82 is positively moved toward closed position and the end 84 of the valve element is always capable of floating so as to insure its finding is correct and 25 perfect seat in the plug 22. In this respect it will also be understood that because of the positive support for the bell crank 60 which insures the end 62 following the same path of movement at all times, the pressure of the spring 52 can have no effect whatsoever on tending to divert the end 84 of the valve away from proper seating position. It is also noted that the structure involves aminimum number of operating parts which may be assembled into a relatively small structure which makes for ease and economy in production. Also, that because of the construction and arrangement of the parts, any particles of grit or other foreign matter that may find its way into the casing will not aifect the proper movement of the parts or interfere with the proper working -of the mechanism. It-may also be noted "that shouldit be desired for any reason or other tot positively hold the valvein open position the cap 54 may be removed and the screw 44 threaded in- 45 wardly until its head contacts with the bottom of the cup 46 and moves the valve to open position. I

This feature not only serves as an aid in the proper assembly of the device, but also provides means whereby positive opening movement of the valve 50 may be accomplished should the occasion arise. By threading the screw 44 in the opposite direction to increase .the compression of the spring 52, it enables the usual cooling unit or evaporator of a refrigerating system to be removed without danger of loss of refrigerant through the expansion valve.

In Fig. 6 is illustrated the application .of substantially the same mechanism illustrated in the previous figures to an expansion valve of the thermostatically operated type. As will be noted in this figure, the parts at the left hand end thereof are identical to the parts previously described except that a cap 90 of different design is substituted for the cap 40 shown in Fig. 1, the metal (55 cup 46a within the bellows 32 has been modified to provide an inwardly facing cone-like projection 92 centrally of its bottom and the spring 52 has been replaced by a spring 94 f slightly different shape and size. The cap 9|] in this case threads onto the casing ill in substantially the same manner as that-previously described but is provided with a threaded portion 96 on which is threadably received what may be known as an insulating spacing casing 88, preferably formed from suitable non-metallic heat insulating material as, for instance, rubber or some phenolic condensation product such as that marketed under the name of Bakelite.

The casing 98 is provided with a head I having a central axially projecting boss I02 in which is closely but slidably received'the right hand end of a tube I04. The tube I04 is preferably formed of the same material as the casing 98. The cap 90 is provided with a centrally apertured boss I06 which is internally threaded for cooperative engagement with the corresponding threaded portion of the tube I04 which projects therethrough. The right hand end of the boss I06 as viewed in the figure may be inwardly tapered on its end face and the exterior of the boss threaded and provided with a nut I08" which may cooperate therewith to compress packing such as 0 about the tube I04 so as to 'ffect a gland therefor. The left hand end of the tube I04 projects into the cup 4011 in the bellows 32 and at its extremity isprovided with a peripheral flange I I2 between which and the ring Eli-the coil spring 94 is maintained under compression.

Midway .of its length the casing 88 is preferably provided with an aperture such as H4 and the tube I04 in approximate alignment transversely with the opening H4 is preferably provided with an hexagonal surface II6 enabling a wrench to be inserted into the casing 98 through the aperure H4 and into engagement with the tube I04 to permit rotation thereof and thus vary the stress of the spring 94 for the purpose of modifying the pressure required to actuate the bellows 32 and consequently the valve element 82'.

Threaded onto the right hand end of the casing 98 is another casing I26 having an end wall I22. Within the casing I20 is a bellows I24, the head of which is fixed against movement to the end wall I22. The left hand end of the bellows I 24 is provided with a head member I26 the central portion of which is depressed inwardly-relative to the bellows to form a cup I28 and the bottom of the cup is formed to provide an inwardly extending cone-like projection I30 similar and opposed to the projection 92 previously described. Freely siidably received within the tube I04 and extendof the bellows I24 communicates through a tube I34, which is usually of the capillary type, with .the usual control bulb or feeler leg I36, it being understood that the bulb I 36, tube I34 and bellows I24 is filled, partially orotherwise, with a suitable refrigerant adapted to vaporize at a desired given temperature, and that the bulb I36 is positioned in,'against or in proximity to the object or chamber, the temperature of which it is desired to control. Obviously, when the temperature of such chamber increases sufficiently to cause a portion of the refrigerant in the bulb I36 to vaporize, the increased pressure in the bulb I36 caused by such vaporization is transmitted through the tube I34 to the bellows I24 and tends to expand the bellows I24. Upon expansion of the bellows I24 the rod I32 will be moved to the left, as viewed in the figure, and cause a like movement of the head of the bellows 32 which, as previously described, will cause the valve element 82 'to be lifted from its seat and permit liquid refrigerant to flow into the casing it. When this flow of' refrigerant through the casing it and into the low pressure side of the refrigerating system causes a predetermined drop in the temperature of the part controlled by the bulb I36, the refrigerant in the bulb I36 will be condensed, causing'a drop in pressure in the tube I36 and bellows I24 which will permit the spring 34 to contract the bellows 32 and move the valve element 82 to closed position.

It is to be particularly noted that in connection with thermostatically operated expansion valves of the general type indicated, considerable difflculty has been experienced in previously suggested constructions due to the fact that the connection provided between the member moved directly by the tube I36, the bellows I24 in the present case, has had some form of metallic connection with the casing of the expansion valve proper and, due to the fact that the liquid refrigerant flowing through the expansion valve reduces the temperature thereof to a material degree, heat is absorbed from the wall moved by the tube I36 and causes the gasified refrigerant therein to be liquefied, thus either destroying or at least rendering inaccurate or unsatisfactory the accurate results for which the device is intended. With the present construction by the employment of the heat insulating casing-98, tube I04 and rod I32 the possibility of heat absorption from the bellows I24 and liquid contained therein by the expansion valve proper is entirely eliminated so that any capable of various modifications and changes without materially affecting the invention involved and, accordingly, it will be apparent that formal changes may be made in the specific embodiment of the inventiondescribed without departing from the spirit or substance of the broad invention, the scope of which is commensurate with the appended claims.

I claim: i 1. In a valve structure, in combination, a casing having a valve seat, a member in said casing movable along a fixed path and having an opening therein, said opening having .a wall portion of restricted dimensions and the walls thereof flaring outwardly from said portion, a needle valve passing through said opening and relatively closely received by said restricted wall portion, said needle valve having a transverse opening therethrough, a central portionof the last mentioned opening being of restricted diameter, and a. pin extending through said opening in said pin and fixed against movement relative to said member at the point of wall restriction of said opening therein, the point of said valve lying in cooperative relation with respect to said seat.

2. In a valve structure, in combination, a casing having a valve seat provided therein, a bell crank pivotally supported in said casing, an arm ofv said bell crank having a threaded opening therein, an apertured plug threadably received in said opening, the aperture in said plug being of restricted diameter between its endsand flaring outwardly therefrom, a needle valve projecting through said aperture with its point in 00- operative relation with respect to said seat, said needle valve having a transverse opening therethrough at the point of restriction of said apering outwardly therefrom, said plug also having avtherein, a bellows sealed) to said casing and ture in said plug, said transverse opening being of restricted diameter between its endsand flartransverse opening therethrough at the point'of restriction of the aperture therein, and a pin extending through said transverse apertures.

3. In awalve structure, in'combination, a casing having a valve seat therein and an opening closing said opening, a spring seat secured to the movable end of said bellows, a headed screw projecting into said bellows and beyond said seat,

a spring held under compression between said seat and the head of said screw,a bell crank supported for pivotal movement within said casing,

means connecting one arm of said bell crankto said movable end of said bellows, said connection being so constructed and arranged that said a bell crank has positive equal movement with said bellows in both directions of movement of said bellows, a needle valve cooperating with said valve seat, and a connection betweensaid needle valve and the remaining arm of said bell crank, the last mentioned connection being so constructed and arranged asto cause constantly positive equal movement of said needle valve in both directions "with Said remaining arim-said screw being movable to a position to engage the said bellows and move it to a position to positively unseat said valve.

4. In a valve structure, in combination, a caspivotally mounted within said casing, a slidable connection between one arm of said bell crank and the closed end of said bellows, said connecs tion being so constructed and arranged as to cause positive equal movementof the end of said arm in both directions with said closed end of said bellows, the other-arm of said bell crank extending into intersecting relation with the extended axis of said valve seat, and a needle valve cooperable with said seat universally connected to said other arm, the last mentioned connection being so constructed and arranged as to cause constantly positive equal movement of said needle valve and said other arm in both directions axially of said valve seat, said screw being movable to aposition to move said closed end of said bellows to positively unseat said valve.

5. An expansion valve structure including 1 V combination, a housing having a valveseat therein, a needle valve member having the point there of arranged in cooperative relation with said valve seat serving to control the passage of fluid therethrough, a fluid pressure responsive device for actuating said needle valve member, a bell crank arm serving to interconnect said fluid, pressure responsive device and said needle valve member,.. said bell crank arm being pivotally connected to said fluid pressure responsive device for positive equal movement therewith in'both directions, a universal connection for interconnecting said bell crank arm and needle valve member serving to permit a limited universal movement of said needle valve member with respect to its seat and at the same timeserving to efiect positivee'qual movement of said needle valve member with said arm'in both directions, means in said universal connection serving to lock said needle valve member againstr'otation about its own axis and a fixed pivotal mounting for saicl'bell crank arm within said housing whereby as said arm is moved said needle valve.member will be moved' toward or away from its seat in a. direction parallel to its EDWARD R. 15E LUIZ.

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