US2408919A - Refrigeration expansion valve - Google Patents

Description

Oct. 8, 1946. E. J. D-ILLMAN El'AL 2,408,919.

REFRIGERATION EXPANSION VALVE Filed April 5, 1945 3 Sheets-Sheet'l u FIG. I y

INVENTORS 5M .Diwm BY W m,

' M ATTORNEY Oct. 8, 1946.

E. J. DILLMAN ETAL REFRIGERATION EXPANSION VALVE Filed April 5, 1945 3 Sheets-Sheet 2 5?) IN VEN TORS X -bu ATTORNEY Patented Oct. 8, 1946 2,408,919 REFRIGERATION EXPANSION VALVE Earnest J. I iillman and Franklyn Y. Carter, De-

troit, Mich., assignors to Detroit Lubricator Company, Detroit, Mich,

Michigan a corporation of Application April 5, 1945, Serial No. 586,668

This invention relates to new and useful improvements in expansion valves for controlling the flow of refrigerant and more particularly to such a valve which is operated in accordance with both the temperature and the pressure of the refrigerant.

In mechanical refrigeration systems of the compressor condenser type it has been customary to utilize an external pressure or equalizer line or conduit to convey pressure from the evaporator outlet to the'valve operating pressure responsive member. It has also been customary to utilize a liquid charged power element having a feeler bulb or member to sense the temperature at the outlet of the evaporator to actuate the power element for operating the valve in accordance with temperature changes.

It is one object of this invention to provide an expansion valve responsive to both the temperature and the pressure adjacent the outlet of the evaporator without the necessity of using either the equalizer connection or the feeler bulb.

Another object is to provide a valve which will respond accurately to both temperature and pressure changes and control the flow of the refrigerant with a minimum of surging.

Another object is to provide a valve which is capable of commercial quantity production and which is of low cost construction.

The invention consists in the improved construction of parts to be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of this specification, there are fully and clearly illustrated several preferred embodiments of the invention, in which drawings Figure 1 is a. view of the expansion valve in side elevation and showing it operatively arranged in a diagrammatically illustrated refrigerant system;

Fig. 2 is a top plan view of the expansion valve showing its connecting conduits;

Fig. 3 is a view in section on the line 3-3 of Fig. 2;

Fig. 4 is a view in section on the line 4-4 of Fig. 2;

Fig. 5 is an enlarged detail view showing the inner connection of the valve operating rod or wire and the diaphragm;

Fig. 6 is an enlarged detail view of a modification showing means for equalizing pressure during stoppage of the compressor;

Fig. 7 is a top plan view of another form of thermostatic expansion valve having the invention;

Fig. 8 is a view in vertical section on the line 8-8 of Fig. '7;

Fig. 9 is a detail view in end elevation of the valve of Fig. ,7;

14 Claims. (01. 62-8) 2 Fig. 10 is a detail view in side .elevation of the valve of Fig. Twith parts broken away to show internal construction, and

Fig. 11 is an enlarged detail view of a modification showing means for anticipating flooding of the evaporator.

Referring to the drawings by characters of reference and particularly Figs. 1 to 5, the numeral I designates generally a motor driven compressor controlled in its cycle of operation by any of the well known devices. The compressor I discharges through a pipe or conduit 2 into the usual condenser 3 which feeds into a receiver 4 from which a pipe or conduit 5 which is the refrigerant liquid line connects as at 6 to the inlet 1 of the thermostatic expansion valve 8 which is shown as of the multiple type having outlet connections 9, I0 connected by pipes or conduits II, I2 respectively to the inlets of evaporators or the multiple passes l3, M of an evaporator. The outlets of the evaporators I3, I13 are connected to a common refrigerant return or suction line or conduit I 5 which is connected by the inlet fitting I6 to the pressure chamber I"! of the expansion valve. The chamber I? is intercalated in the suction line and flow from the chamber discharges through an outlet fitting I8 having connected thereto the suction lineor conduit I9 which connects into the suction side of the com- 4 having an external portion 24 and an internal At the inlet 7 end of the portion 24 which connects to the valve inlet 1, the hollow interior or bore of the portion I portion 25 within the chamber I1.

24 is enlarged as at 26 to provide a valve chamher. The outlet end of the chamber 26 is provided with a counterbore to receive a tubular valve seat member 2! which projects into the chamber 26. Surrounding and fitting the projecting end portion of this valve seat member 21 there is a tubular strainer'member 28 within the valve chamber 26 and whichis closed at its end adjacent theinlet 7. Within the strainer member 28 there is a valve member 29 cooperable with the valve seat member 21 to close the valve port 30 and to throttle flow therethrough. The valve member 29 has a longitudinal bore therethrough which receives a flexible operating rod or wire 3| which fits the valve member bore andis secured to the valve member by solder as at 3I which also seals the valve member bore. -Closely adjacent and preferably at or in the wall 22, the borepf the tubular member 23 on the outlet side of the valve seat member 29 has outlet ports 32, 33 leading into outlet conduits 34 (of which but one is shown in section) which have one side formed by the wall 22 and which receive the fittings 9, I respectively. The ports 32, 33 and the conduits 34 are in direct heat exchange contact with the wall 22 so that the temperature of the refrigerant medium leaving the valve is conducted directly to the casing 20. The bore 35 in the tubular member 23 extends into the internal portion 25 and is closed at its inner end by an end wall 36 having a central aperture therethrough through which the valve operating wire 3| extends. This end wall aperture is closed and sealed by a washer or packing member 31 within the bore 35 and having a tight sliding fit on the wire 3|. The washer 31 is held against the end wall 36 by a helical coil spring 38 under compression and seating at one end on the washer and at its other end against the valve seat member 21. The wire 3| extends into the chamber l1 and has its end extending through a central aperture in a spring abutment member or disc 39. This wire end has a head 40 seating in a recess in the disc 39. The head 49 is held in the disc recess by a diaphragm reinforcing pad or plate 4|, see Fig. which is welded to the disc at a plurality of points such as indicated by the letter B. Surrounding the internal tubular member portion 25 there is a helical coil spring 42 which seats on the disc 39 and which is held under compression at its other end by an adjustable disc or abutment member 43 which is screw threaded on the portion 25. The edge of the disc 43 is serrated or toothed for cooperation with an adjusting pinion which is insertable into the chamber I! through the opening 44 normally closed by the cap member 45. The diaphragm reinforcing pad 4| seats on a metal diaphragm 46 which is reinforced by a spider 41. The diaphragm and spider seat at their marginal edge portion on a downward facing annular shoulder 48 adjacent the rim of and in the casing side wall 2|. The spider 41 is secured as by welding at its midpoint indicated by the letter A to a stop and supporting member 49 having an ofiset rim 50 engageable with a cap or cover member 5| which holds the diaphragm in position against the shoulder 48. The cap member 5| forms with the diaphragm 46 the sealed chamber 52 of the temperature responsive valve operating power element. The chambers 52 and I! are simultaneously sealed and the diaphragm 46 and cap member 5| are sealed to each other and to the casing 20 by a single solder seal as at 53, the solder filling an annular chamber or recess at the rim edge of the diaphragm and between the cap member and the casing side wall 2|. The cover or cap member 5| is provided with a filling or charging tube 54 which opens into the chamber 52 and by which the chamber 52 may beevacuated of air and charged with a suitable volatile liquid of such minute quantity that at some temperature above the operating range of the valve (which might he, say 50 F. or 60 F. in a valve used in air conditioning), all of the liquid will be in vapor state thereby limiting the maximum pressure in the chamber 52 and acting on the diaphragm 46. The end wall 36 terminates closely adjacent the diaphragm so as to be engaged by the abutment disc 39 to limit the flexing of the diaphragm by the pressure within the chamber 52 and thereby serve as a stop and support to limit maximum diaphragm expansion.

4 The operation of the valve of Figs. 1 to 5 is as follows: The spring abutment disc 43 will have been adjusted to determine the superheat setting or operation of the valve so that the valve will close at a predetermined difierence of temperature between the temperature of the refrigerant .leaving the valve for supply to the evaporator and the temperature of the refrigerant leaving the evaporator. When the compressor is started in operation, the reduction of pressure in the valve casing pressure chamber I! will permit the diaphragm 46 to expand under the force of the vaporized liquid in the chamber 52 thereby moving the valve member 29 to open position. Refrigerant medium will therefore flow through the valve port and outlet ports 32, 33 and the outlet conduits 34 to the evaporators I3 and I4. As soon as the valve member 29 opens and admits refrigerant medium to the conduits 34, there will be a cooling of the casing 20 and a consequent withdrawal of heat from the power element chamber 52 thereby anticipating the flooding of the evaporators and causing the valve member 29 ;to be throttled or moved toward port closed posi- --in the rate of refrigerant supply to the evaporators is materially reduced so that danger of fiooding over of refrigerant medium into the chamber I! is eliminated. Flooding over of refrigerant medium into the chamber I! would cause complete closure of the valve member 29 with consequent starving of the evaporators and inefiicient operation. In addition throttling of the valve member in anticipation of flooding of the evaporator permits substantially all of the evaporator to be utilized for refrigeration as distinguished from only a partial utilization of the entire length of the evaporators when surging occurs. When the temperature of the refrigerant medium in the chamber decreases and approaches the superheat setting of the valve, then the pressure exerted by the vapor of the volatile liquid in the chamber 52 will decrease so as to permit the spring 42 to move the valve member 29 further toward closed position. The pressure in the power element chamber 52 will vary with the temperature of the vaporized refrigerant medium in the chamber during the operation of the compressor and move the valve 29 toward open and closed position to regulate admission of refrigerant medium to the evaporators for maximum efiiciency.

Referring to Figs. 7 to 10 inclusive, the valve 8 has a housing or body member including a cuplike casing 60 and a tubular member 6|. The casing 60 is formed by stamping or drawing of a disc of sheet metal intothe shape of a cup having a cylindrical sid wall 62 with an annular internalshoulder 63 adjacent its rim or open end and having a bottom wall 64 which forms the upper end wall of the chamber IT. The wall 64 has a central depression or recess through which there is an aperture 65 receiving the tubular member 6|. The tubular member 6| is provided with an annular shoulder which seats on the rim or marginal edge ofaperture 65 and this joint is sealed and the members 6!! and 6| are rigidly secured and sealed together by waging of the material of the member 6| over upon the end wall 64 and by then solder sealing the joint. The outer or external face of the casing end wall 64 is provided with one or more radial recesses or grooves 66 extending from the central end wall recess. Alined with these recesses which are of partial cylindrical cros section, see Fig. 9 there are cylindrical recesses in the side wall of the tubular member 6!. Accordingly, outlet tubes or conduits 6? will have side wall portions fitting the end wall grooves or recess 66 and have their ends extending into and fitting the tubular member recesses or sockets as at 68 which joints are sealed by solder. The contact between the conduits 5? and the end wall [it is also a solder connection so that the conduits 61 are in direct and intimate heat exchange with the casing 60 and the end wall The bore 69 of the tubular member 8! has within the external tubular member portion it an enlarged diameter bore portion ll providing a valve chamber with its inlet provided with a conical strainer member 12. At the outlet end of the chamber H the bore 69 has a counterbore to receive a valve seat member 13. Coperable with the valve seat member "13 there is a valve member i l secured and sealed to a flexible operating rod or wire l all as described in connectionwith Figs. 1 to 5. The bore 69 on the outlet side of the valve seat member 13 has outlet ports 15 opening into the conduits 61. In this form of valve the helical coil spring 38 within the tubular member interior portion 25 does not seat against the valve seat member is but is held under compression by a separate sleeve member Tl press fitted within the bore 59 below the ports 76 which are between the sleeve member 11 and the valve seat member 13. Through the casing side wall 62 at diametrically opposite points directly underlying and parallel to the conduits 51 there are apertures which receive and have sealed therein an inlet fitting l8 and an outlet fitting 19 which are for connection to the suction line conduits l5 and I9, respectively so that the chamber ll is intercalated in the suction line. The valve chamber H has an inlet fitting 3d by which the valve may be connected to the refrigerant liquid line or conduit 5. The remaining structure of this valve is substantially identical to that of the valve of Figs. 1 to 5, and therefore, the primes of reference characters applied to Figs. 1 to 5 will designate the like parts of this Valve, Figs. 7 to 10. It may be noted however, that the spring abutment disc has its serrated rim offset so that it alines with the suction line fittings 18 and "59 thereby eliminating the necessity for the aperture dd since the disc 43' is adjustable through the suction line openings prior to installation of the valve. The operation of this valve of Figs. '7 to 10 will be apparent from the foregoing descri ticn of the valve of Figs. 1 to 5 when it is installed. in the refrigeration system of Fig. 1.

In Fig. 6 the valv seat member 2'! or 13 is shown as provided with a fixed by pass orifice or bleed 96 which is of such small size that it will not upset the control of the feeding of refrigerant medium by the valv when the compressor is in operation. However, this bleed will permit the pressure to equalize in the system during the off cycle or while the compressor is at rest and thereby provide an unloading means prior to the compressor being again placed in operation on the refrigerating cycle.

In Fig. 11 the tubular member interior portion is provided with a calibrated bleed orifice I99 which discharges into the chamber H and against the valve operating diaphragm. Accordingly, when the valve member 29 opens some refrigerant medium will be supplied directly to the chamber ll in by passing relation to the evaporad tors and increase the cold effect on and the abstraction of heat from the power element chamber 52. This will result in more quickly anticipating the flooding of the evaporators and in causing a greater extent of throttling of the valve member so as to still further reduce the rate of refrigerant medium to the evaporators.

It will be apparent that the by pass bleed or orifice lot of Fig. 11 is equally applicable to either of the valves above described. It will also be apparent that th bleed of Fig. 6 can likewise be utilized with both of the described valves and can also be utilized with the by pass bleed IUD of Fig. 11.

Having thus described the invention, What is new and desired to be covered by Letters Patent of the United States is:

1. An expansion valve comprising a cup-like casing having an end wall and an opposite open side, a pressure responsive diaphragm closing and sealing said open side, a cap member sealed to said casing and to said diaphragm and forming with said diaphragm a temperature responsive pressure chamber, a volatile liquid in said chamber, said casing having inlet and outlet openings for flow of vaporized refrigerant medium through said casing in contact with said diaphragm, a tubular member projecting externally from said end wall concentric with said diaphragm and having a longitudinal passageway therethrough opening into said casing, a valve seat member in said passageway, a valve member in said passageway on the inlet side of said seat member, valve operating means extending through said passageway and said seat member and connecting said valve member to said diaphragm, said tubular member having an outlet from said passageway external of said casing, and means sealing said passageway around said valve operating means on the casing side of said outlet.

2. An expansion valve comprising a cup-like casing having an end wall and an opposite open side, a pressure responsive member closing and sealing said open side, a cap member sealed to said casing and to said responsive member and forming with said responsive member a temperature responsive pressure chamber, a volatile liquid in said chamber, said casing having inlet and outlet openings for flow of vaporized refrigerant medium through said casing in contact with said responsive member, a tubular member projecting externally from said end wall concentric with said responsive member and having a longitudinal passageway therethrough opening into said casing, a valve seat member in said passageway, a valve member in said passageway on the inlet side of said seat member, valve operating means extending through said passageway and said seat member and connecting said valve member to said responsive member, said tubular member having an outlet port from said passageway external of said casing, a conduit loading from said outlet port and having direct heat exchange contact with said casing end wall, and means sealing said passageway around said valve operating means on the casing side of said outlet.

3. An expansion valve comprising a cup-like casing having an open side, a tubular member having a longitudinal passageway therethrough transverse to the end wall of said casing and having inner and outer end portions projecting from opposite faces of said wall, said outer end portion having a passageway inlet and having a laterally directed passageway outlet, a valve seat member in said passageway between said inlet and said outlet, a valve member in said passageway inlet and cooperable with said seat member, a diaphragm closing the open side of said casing, a reinforcing member movable with said diaphragm and interposed between said inner end portion and said diaphragm, a flexible wire extending through said passageway and operatively connecting said diaphragm to said valve member, said reinforcing member being engageable with said inner end portion to limit valve member movement, a cap member sealed to the open side of said casing and cooperating with said diaphragm to form a pressure chamber, a volatile liquid in said chamber operable on temperature increase to move said valve member toward said open position, said casing having inlet and outlet ports in its side wall and positioned between said end wall and said diaphragm for flow of refrigerant through said casing in contact with said diaphragm.

4. An expansion valve comprising a cup-like casing having an open side, a tubular member having a longitudinal passageway therethrough transverse to the end wall of said casing and having inner and outer end portions projecting from opposite faces of said wall, said outer end portion having a passageway inlet and having a laterally directed passageway outlet, a valve seat member in said passageway between said inlet and said outlet, a valve member in said passageway inlet and cooperable with said seat member, a diaphragm closing the open side of said casing, a flexible wire extending through said passageway and operatively connecting said diaphragm to said valve member, a sealing washer closing the inner end of said passageway and having a sliding fit on said wire, a helical coil spring held under compression by and between said seat member and said washer and holding said washer in passageway closing position, a cap member sealed to the open side of said casing and cooperating with said diaphragm to form a pressure chamber, a volatile liquid in said chamber operable on temperature increase to move said valve member toward open position, said casing having inlet and outlet ports in its side wall and positioned between said end wall and said diaphragm for flow of refrigerant through said casing in contact with said diaphragm.

5. An expansion valve comprising a cup-like casing having an open side, a tubular member having a longitudinal passageway therethrough transverse to the end wall of said casing and having inner and outer end portions projecting from opposite faces of said wall, said outer end portion having a passageway inlet and having a laterally directed passageway outlet, a valve seat member in said passageway between said inlet and said outlet, a valve member in said passageway inlet and cooperable with said seat memher, a diaphragm closing the open side of said casing, a flexible wire extending through said passageway and operatively connecting said diaphragm to said valve member, a spring abutment member adjustable on said inner end portion, a helical coil spring held under compression by and between said abutment member and said reinforcing member and opposing movement of said valve member by said diaphragm, a cap member sealed to the open side of said casing and cooperating with said diaphragm to form a pressure chamber, a volatile liquid in said chambar operable on temperature increase to move said valve member toward open position, said casing having inlet and outlet ports in its side wall and positioned between said end wall and said diaphragm for flow of refrigerant through said casing in contact with said diaphragm.

6. An expansion valve comprising a sheet metal cup having a central aperture through its end wall and having side wall apertures, conduit flttings secured and sealed in said side wall apertures, a tubular member extending through said central aperture and sealed therein, a diaphragm closing and sealing the open side of said cup, a sheet metal cap member sealed to said diaphragm and to said casing and forming with said diaphragm a temperature responsive pressure chamber, a volatile liquid in said chamber, said tubular member having a longitudinal passageway therethrough and having a cylindricai side wall recess external or said cup and communicating with said passageway, a conduit fitting secured and sealed in said side wall recess, valve means in said passageway on the inlet side of said recess, means extending through said passageway and operatively connecting diaphragm to said valve means, and means closing the inner end of said passageway around said connecting means.

7. An expansion valve comprising a sheet metal cup having a central aperture through its end wall and having side wall apertures, metal tubing secured and sealed in said side wall apertures, a tubular member extending through said central aperture and sealed therein, a diaphragm closing and sealing the open side of said cup, a sheet metal cap member sealed to said diaphragm and to said casing and forming with said diaphragm a temperature responsive pressure chamher, a volatile liquid in said chamber, said tubu lar member having a longitudinal passageway therethrough and having a cylindrical side wall recess external of said cup and communicating with said passageway, said end wall having a radial recess alined with said side wall recess, metal tubing secured in said radial recess and sealed in said side wall recess, valve means in said passageway on the inlet side of said recess, means extending through said passageway and operatively connecting said diaphragm to said valve means, and means closing the inner end of said passageway around said connecting means.

8. An expansion valve comprising a sheet metal cup having a central aperture through its end wall and having side wall apertures, conduit fittings secured and sealed in said side wall apertures, a tubular member extending through said central aperture and sealed therein, a diaphragm closing and sealing the open side of said cup, a sheet metal cap member sealed to said diaphragm and to said casing and forming with said diaphragm a temperature responsive pressure chamber, a volatile liquid in said chamber, said tubular member having a longitudinal passageway therethrough and having a cylindrical side wall recess external of said cup and communicating with said passageway, said tubular member having its inner end terminating adjacent said diaphragm to limit inward movement of said dia phragm, a spring surrounding said tubular member inner end and opposing inward movement of said diaphragm, a conduit fitting secured and sealed in said side wall recess, valve means in said passageway on the inlet side of said recess, means extending through said passageway and operatively connecting said diaphragm to said valve means, and means closing the inner end of said passageway around said connecting means.

9. An expansion valve having an operating range in which it automatically throttles refrigerant medium flow, comprising a cup-like casing having an end wall and an opposite open side, a pressure responsive diaphragm closing and sealing said open side, a cap member sealed to said casing and to said diaphragm and forming with said diaphragm a temperature responsive pressure chamber, a minute quantity of fluid in said chamber and operable by condensation and vaporization in the operating range of the valve to actuate said diaphragm, said fluid being all in vapor state at a temperature above the operating ran e of the valve, said casing having inlet and outlet openings for flow of vaporized refrigerant medium through said casing in contact with said diaphragm, a tubular member projecting externally from said end wall concentric with said diaphragm and having a longitudinal passageway therethrough opening into said casing, a valve seat member in said passageway, a valve member in said passageway on the inlet side of said seat member, Valve operating means extending through said passageway and said seat member and connecting said valve member to said diaphragm, said tubular member having an outlet from said passageway external of said casing, and means sealing said passageway around said valve operating means on the casing side of said outlet.

10. An expansion valve comprising a cup-like casing having an end wall and an opposite open side, a pressure responsive diaphragm closing and sealing said open side, a cap member sealed to said casing and to said diaphragm and forming with said diaphragm a temperature responsive pressure chamber, a volatile liquid in said chamber, said casing having inlet and outlet openings for flow of vaporized refrigerant medium through said casing in contact with said diaphragm, a tubular member projecting externally from said end wall concentric with said diaphragm and having a longitudinal passageway therethrough opening into said casing, a valve seat member in said passageway, a valve member in said passageway on the inlet side of said seat member, valve operating means extending through said passageway and said seat member and connecting said valve member to said diaphragm, said tubular member having an outlet from said passageway external of said casing, and means to bleed refrigerant medium from said passageway into said casing adjacent said diaphragm.

11. An expansion valve comprising a cup-like casing having an end wall and an opposite open side, a pressure responsive diaphragm closing and sealing said open side, a cap member sealed to said casing and to said diaphragm and forming with said diaphragm a temperature responsive pressure chamber, a volatile liquid in said chamber, said casing having inlet and outlet openings for flow of vaporized refrigerant medium through said casing in contact with said diaphragm, a tubular member projecting externally from said end wall concentric with said diaphragm and having a longitudinal passageway therethrough opening into said casing, a valve seat member in said passageway, a valve member in said passageway on the inlet Side of said seat member, valve operating means extending through said passageway and said seat member and connecting said valve member to said diaphragm, said tubular member having .an outlet from said passageway external of said casing, means to bleed refrigerant medium from the inlet side to the outlet side of said seat member when said valve member is closed, and means sealing said passageway around said valve operating means on the casing side of said outlet.

12. An expansion valve comprising a cup-like casing having an end wall and an opposite open side, a pressure responsive member closing and sealing said open side, a cap member sealed to said casing and to said member and forming with said member a temperature responsive pressure chamber, a volatile liquid in said chamber, said casing having inlet and outlet openings for flow of vaporized refrigerant medium through said casing in contact with said member, a tubular member projecting externally from said end wall concentric with said member and having a longitudinal passageway with an inlet and an outlet external of said casing, a valve seat member in said passageway between said inlet and said outlet, a valve member in said passageway cooperable with said seat member, and valve operating means connecting said valve member to said pressure responsive member.

13. An expansion valve comprising a sheet metal cup having a central aperture through its end wall and having side wall apertures, conduit fittings secured and sealed in said side wall apertures, a tubular member extending through said central aperture and sealed therein, a pressure responsive member closing and sealing the open side of said cup, a sheet metal cap member sealed to said responsive member and to said casing and forming with said responsive member a temperature responsive pressure chamber, a volatile liquid insaid chamber, said tubular member having a longitudinal passageway open at its end external of said cup and having a cylindrical side wall recess external of said cup and communicating with said passageway, a conduit fitting secured and sealed in said side wall recess, valve means in said passageway, and means operatively connecting said responsive member to said valve means.

14. An expansion valve comprising a, stamped sheet metal cup having an outward facing shoulder adjacent its rim and having alined side wall apertures, the end wall of said cup having a central aperture, metal tube fittings secured and sealed in said side wall apertures, a tubular member extending through and sealed in said central aperture and having a shoulder seating on said end wall, said tubular member having its end external of said cup open and having a side wall opening external of said cup, a metal tube fitting secured and sealed in said side wall opening, valve means in and controlling flow through said tubular member, a pressure responsive member seating on said shoulder and sealing the open side of said cup, a stamped sheet metal cap member seating on said responsive member and fitting said cup, means sealing said responsive member and said cap member to said cup, a volatile liquid in said cap member, and means operatively connecting said responsive member to said valve means.

EARNEST J. DILLMAN. FRANKLYN Y. CARTER.

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