US2152781A - Control device - Google Patents

Description

D. n. w'iLE CONTROL DEVICE Filed March 13, 1955 April 4, 1939.

Patented Apr. 4, 1939 CONTROL DEVICE Daniel B. Wile, Detroit, Mich, assignor to Detroit Lubricator Company, Detroit, Mich., a corporation of Michigan Application March 13, 1935, Serial No. 10,952

' 14 Claims.

My invention relates generally to control devices, and more particularly to automatic expansion valves.

One of the objects of my invention is to provide an automatic expansion valve having a new and improved arrangement of the operating parts thereof.

Another object of my invention is to provide a new and improved automatic expansion valve having a closed chamber for containing a gas under a predetermined desired pressure, the structure forming the chamber being so constructed and the chamber being sealed in such a manner as to preclude any possibility of the gas escaping therefrom.

Another object of the invention is to provide an expansion valve control device having a new and improved valve actuator and cooperating parts which are sensitive in operation yet durable in construction.

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

In the accompanying drawing, to be taken as a part of this specification, I have fully and clearly illustrated a preferred embodiment of my invention, in which drawing-- cross section of my improved automatic expansion valve;

Fig. 2 is a view shown partly in cross section and partly in elevation, taken in the direction of the arrows 2-2 of Fig. 1;

Fig. 3 is a detail View of a part of my device shown disassembled therefrom, and

Fig. 4 is a view of the part shown in Fig. 3 as seen looking from left to right.

Referring to the drawing, there is shown an automatic expansion valve of the type for maintaining a. desired fluid pressure in a container and one which is particularly adapted for use with refrigerating systems for maintaining a de- 43 sired evaporator temperature by controlling the admittance of refrigerant to the evaporator to maintain a pressure therein corresponding to the temperature desired. The automatic expansion valve includes a body I which may be cym) lindrical in shape, as shown, and which preferably has one end recessed, as at 2. The inner side wall of the recessed end of the body I is preferably circular in contour and stepped, providing an outwardly facing continuous annular.

5:, shoulder or seat 3. At the outer end of the Figure 1 is a side view shown in longitudinal the inner side wall 4, having the larger diameter, is preferably tapered or flared outwardly along the entire periphery thereof and toward the open end of the recess, as at taper preferably starts at outwardly of the shoulder 5. The a point beyond and 3 so that a circular portion of the inner wall adjacent the shoulder 3 is substantially perpendicular thereto, as shown.

Mounted on the shoulder 3 of the body- I, and in the portion of larger diameter, is a flexible wall means or diaphragm I, cooperates with the inner one side of which recessed endwall 2 and the circular side wall 9 of the body to provide a chamber or passageway III. In the present instance, the diaphragm I is in the form of a circular pan-shaped member having a circumferential reenforcing flange ll tends outwardly from which exthe shoulder 3 when the diaphragm is in operativeposition. Preferably the pan-shaped diaphragm I into the recessed end erably its reenforcing flange point at which the inner wall point beyond the of the body starts to there is a space between the inner tapered telescopes snugly of the body I, and prefll extends to a taper outwardly so that circular wall 5 of the body and the outer circular wall of the diaphragm flange H, the purpose of which is hereinafter described.

Mounted within the recessed end of the body land within the pan-shaped diaphragm I is a circular shaped reenforcing or backing plate l2,

the outer circular edge portion of whichis in bearing engagement with the outer circular portion of the diaphragm 1. The backing plate I! is preferably substantially concave-convex or spherical in shape, with the concave face there-' of disposed toward the. relation thereto so diaphragm land in spaced that small flexing movement of the, diaphragm is permitted toward the backing plate but movement which would cause rupture of the diaphragm, developing in chamber due to excessive pressure I0, is prevented by the backing plate which acts as a stop. The plate I! may be formed of desired, and in which sheet metal, as shown, if

case the plate is ably formed with an outwardly bent, circularly extending portion or of the plate to give a rib however being spaced ginal edge of the plate As shown,

seating surface.

rib I3 adjacent the edge dded rigidity thereto, the

inwardly from the marto provide an annular the backing plate l2 preferably telescopes snugly into the panshaped diaphragm 1 gaging the inner wall 0 of the diaphragm I.

and has its periphery enprefer-q f the reenforcing flange II A housing member or cap I4 having an open side is mounted on the end of the body I and extends into the recessed end of the body I with its open side disposed toward the reenforcing plate I2. The housing member I4 is formed with a circular outwardly extending flange I5 providing a continuous circular bearing surface for bearing against the marginal annular seating surface of the reenforcing plate I2. The housing member I4, like the reenforcing plate, telescopes within the pan-shaped diaphragm I, the circular edge of the housing flange I5 being in engagement with the inner wall of the diaphragm re-. enforcing flange II.

Preferably the housing member I4, reenforcing plate I2 and diaphragm 'I are secured to the body I by filling the space between the inner tapered wall 5 of the body I and the outer wall of the housing member I4 with a suitable sealing and securing means such as solder, indicated at I6. It will be seen that by reason of the inner wall of the body I being tapered, as at 5, and the outer wall of the housing member I4 being spaced from the inner wall of the diaphragm flange II by reason of its circular flange I5, solder may be inserted between the outer wall of the housing member I4 and the inner wall of the diaphragm reenforcing flange II and between the outer wall of the diaphragm reenforcing flange I I and the inner tapered wall of the body I, thus securing the parts together and to the body I and providing a good fluid-tight seal therebetween. The housing member I4 and the diaphragm I thus cooperate to form a sealed chamber I8, which chamber is charged with a fluid which mav be a gas and preferably an inert gas such as nitrogen. By utilizing an inert gas, such as nitrogen, or other gas which will not react with the surrounding metallic parts in contact therewith, the pressure of the gas at constant temperature w ll remain substantially constant over a long period of time which would otherwise decrease in pressure due to loss of gas through chem cal reaction. The gas is contained in the chamber I8 under a predetermined desired pressure to exert a corresponding force on the diaphragm to flex it inwardly when the force exerted on the opposite side of the d aphragm becomes less than the force exerted by the gas. The force exerted by the gas is determined by the quantity of gas contained in .the chamber I8. The reenforcing plate I2 is provided with a central aperture I9 in coaxial alignment with the center of the diaphragm 1 providing a passageway for the compressed gas so that it exerts its force on the adjacent side of the diaphragm.

Preferably the gas is introduced into the chamber I8 through tubing 20, one end of which is preferably threaded for threading into a threaded aperture provided in the cap I4. Preferably the air in chamber I8 is first removed through the tubing 20 after which the gas is introduced under pressure thereinto. When the desired quantity of gas has been introduced into chamber I8, the tubing 20, which is preferably soft metallic tubing, may be flattened at a point beyond the outer wall of the c ap I4, such as by pinching the tubing with pliers, to prevent the escape of gas therethrough; while a suitable sealing material such as solder, indicated at 20, is applied to.

insure against leakage'of the gas between the tubing and the cap.

Centrally of the body I and in axial alignment with the center of the circular diaphragm I is provided a bore 25 which serves as a valve chamber. The bore 25 extends to a point adjacent the chamber III, there being a transverse wall 26 between the chamber I0 and the end of bore 25 and in which wall is provided an aperture for receiving a tubular shaped valve seat member 21. The tubular shaped valve seat member may be pressfitted or otherwise suitably fixed in the transverse wall 28. The inner end of the valve seat member 21 cooperates with the conical face 28 of a needle valve 29, which valve is mounted on a guide or piston 30 for reciprocal movement in bore 25. The piston or valve retainer 30 may be tubular in shape having a bore in the end adjacent the valve seat and in which the needle valve 29 may be press-fitted or otherwise suitably secured.

Preferably the bore 25 is counterbored at its open end and threaded to receive an externally threaded tubular shaped closure plug '32, the counterbore being provided so that the inner wall of the tubular plug 32 can be made to coincide with or be flush with the inner wall of bore 25 to provide a continuous unbroken surface, as shown. The valve body is preferably provided with a recess or channel surrounding the outer end of plug 32 to receive sealing material such as solder, indicated at 33, between the plug 32 and body I to prevent leakage/ around the plug. Disposed within the tubular shaped plug 32 is a coil spring 35 under compression having one end bearing against the inner end wall of the plug 32 and the other end receiving a projecting portion on and bearing against the piston 30 and urging the valve 29 against its seat or toward closed position. The piston 30 is provided with a circular flange portion 36 which serves as an abutment for one end of the spring 35 and the peripheral edge of which slidably engages the wall of the bore 25 to guide the valve and to prevent vibratory-motion of the valve and spring and resultant noise. The outer diameter of the piston 30 is preferably such that a space or chamber 31 is provided between the piston 30 and the bore 25 for the entrance of refrigerant.

D sposed within the chamber I0 between the diaphragm I and the valve 29 is a thrust member or spider for transmitting the inwardly .flexing movement of the diaphragm I to the valve 29 to open the same when the pressure in chamber I8 acting on one side of the diaphragm 6 exceeds the opposing force exerted on the oppo-' site side of the diaphragm, namely the force exerted by the spring 35 plus the pressure in chamber III. The spider 40 comprises a plate member 4|, which may be formed of sheet metal, and a pin 42 rigidly fixed to the plate. The plate 4| is preferably formed having a central embossed or offset portion 43 which may be circular in shape and in the center of which is provided an aperture for receiving one end of the pin 42. The pin 42 may be rigidly secured to the plate H such as by peening over the end of the pin, thus riveting it to the plate. In the other end of the pin 42 is provideda recess in the form of a central axial bore 44 which when the spider is in operative position receives the pointed end of the needle valve 29. The pin 42 extends into the tubular valve seat member 21 but is rela-\ tively smaller than the inner diameter of the valve seat member to permit the passage of reirigerant between the pin 42 and inner wall of the tubular valve seat member.

The plate 4| is preferably formed as shown in Figs. 3 and 4 having a plurality of radially disposed and substantially equally spaced resilient fingers 45 and alternate and relatively shorter and wider rigid portions 41. The plate 4| and the portions 41 are preferably given additional rigidity such as by forming the plate with ribs, as at 48. Normally the resilient fingers 48 are bent uniformly out of the plane of the plate, as shown in Fig. 4, so that when the spider is in operative position, as shown in Fig. 1, the fingers 46 engage fiat against the diaphragm 'l in the plane of plate 41 and are held under compression between the diaphragm 1 and the valve 29. The force exerted by the resilient fingers 46 thus serves to maintain the pin 42 in engagement with the pointed end of the valve 29.

At one side of the center bore 25 is provided an inlet passage 53 in the form of a bore and which extends substantially parallel with bore 25 and to a point adjacent the chamber NJ where it is in communication with the central bore or valve chamber 25 through a connecting bore 5|. The wall surrounding the inlet end of the inlet passage 50 is preferably tubular in'shape and externally threaded for threaded engagement with a nut 52. A tubular shaped strainer 53 is disposed in the inlet passageway 50 and is supported therein by a nipple 54 which in turn is clamped to the body I by the nut 52. Between the nipple 54 and nut 52 is clamped the flared end of a refrigerant feed or supply conduit 55 through which refrigerant is delivered by the compressor of a refrigerating system (not shown) to the control device. On the other side of the central bore 25 and oppositely disposed to the inlet bore 50 is the outlet passage which includes two intersecting bores 51 and 58, the bore 51 being in communication with chamber l0 and extending substantially parallel to the valve chamber bore 25, and bore 58 being disposed transverse to bore 51 and leading out of the body I. The outlet passage may be connected in communication to a refrigerant evaporator (not shown) such as by a nipple (not shown) or in any other suitable manner.

The'operation of the expansion valve control device in connection with a refrigerating system to maintain a desired evaporator temperature is as follows: As previously stated, the chamber I8 is charged with a gas under pressure and preferably an inert gas, such as nitrogen, so that it will not cause oxidation, and as a result will exert a definite and constant pressure on the diaphragm. The force of the compressed gas in chamber l8 acting on the diaphragm tends to move the valve toward open position while the spring 35 plus the pressure of the refrigerant in chamber l0 opposes the force exerted by thegas and tends to move the valve toward closed-position. Thus, the difference between the force exerted by the gas in chamber l8 and the opposing force of the spring 35 determines the pressure which will be maintained in chamber l0 and in the evaporator and the correspondingevaporator temperature that will be maintained. For example, if the pressure in chamber III was maintained constant, then the opposing force on each side of the diaphragm 1 would be in balanced relation. However, the pressure within the evaporator and consequently the pressure within the chamber ll! of the control device fluctuates within limits and because of this fluctuation, the opposing forces are unbalanced, which causes a throttling of the valve 29 to maintain a substantiallyconstant pressure in chamber "I. It will be seen that the control device may be adjusted to maintain a different substantially constant pressure in an evaporator by changing the force exerted by the spring 35 by means of the threaded plug 32. If, for example, the force exerted by the spring 35 tending to close the valve is decreased, the pressure maintained in chamber I0 will be increased and the evaporator maintained at a corresponding and higher temperature. When the force exerted by the spring 35 is increased, it will be seen that less pressure in chamber ID will be necessary to balance the force exerted by the constant pressure of the gas so that a corresponding and lower temperature will be maintained in the evaporator. When a refri erating system employing the control device isshut down, the valve 29 is maintained in closed position by reason of the increased back pressure in chamber In, caused by the expanding and relatively warmer gas therein. When the compressor of the refrigerating system is started, the

.gaseous refrigerant in chamber I0 is withdrawn and the pressure therein reduced, and when the pressure decreases to a certain point such that the combined pressure of the refrigerant in chamber l0 and the spring 35 is' less than the cons'tant pressure of the gas inchamber l8, then the diaphragm will be flexed inwardly and the spider 40 transmitting its motion to the valve moves the same away from its seat or toward open position. When this occurs, refrigerant from chamber 25 enters chamber Ill from whence it passes through outlet port 58 to the evaporator. When the force exerted by the pressure in chamber l0 plus the force exerted by the spring 35 approaches toward equalling the force exerted by the constant pressure gas in chamber l8, then the valve 29 will be moved toward closed position. I From the foregoingdescription, it will now be seen that I have provided an automatic expansion valve control device having a new and improved arrangement of the operating parts thereof. It will also be seen that I have provided an expansion valve control device having a new and improved sealed chamber construction in which chamber an inert gas is contained under pressure construction of the spider and its arrangement to maintain spring bearing engagement with the valve and the diaphragm and by reason of its floating relationship therebetween, that is, its arrangement to transmit inward flexing movement of the" diaphragm to the valve without being fixedly connected to either, results in its being self-centering relative to the axis of the valve and the center of the diaphragm. Consequently, there is no tendency of the spider to cant or move. in a direction angularly to the natural direction of movement of the valve and diaphragm which would be the case if the spider was connected to either the valve or diaphragm or both because of the difiiculty of aligning the parts. As a result of the elimination of any tendency of the spider tolcant, it will be seen that undue side strain is not placed on the diaphragm'nor on the reciprocating valve structure which otherwise would increase frictional engagement between the reciprocating valve structure and the wall of its chamber and restrict free reciprocating movement of the valve. Also in this connection, the spring fingers of the spider not only maintain bearing engagement of the spider with the valve and diaphragm and prevent canting of the spider but also because of their equally spaced bearing engagement over a large area of the diaphragm and because of the equal pressure imparted to the fingers by the diaphragm, the fingers also serve to prevent rupture of the diaphragm.

What I claim and desire to secure by Letters Patent of the United States is:

1. An expansion valve comprising a body portion having an inlet port and an outlet port, a valve port in said body portion providing communication between the inlet and outlet ports, a reciprocal valve in said body portion for cooperating with said valve port to control flow of fluid therethrough, means in said body DQ tion for urging said valve toward closed position. a housing member mounted on said body portion, a. diaphragm disposed between said body portion and said housing member and flexible to move said valve toward open position, said diaphragm and said housing membercooperating to provide a closed hermetically sealed pressure chamber, a quantity of inert gas contained in said chamber at a predetermined desired constant pressure onerable for flexing said diaphragm to open the valve when the pressure on the other side of said diaphragm decreases below a predetermined pressure, and means securing said housing member and said diaphragm to said body portion and hermetically sealing said pressure chamber.

2. An expansion valve comprising a casing having an inlet port and an outlet port, a flexible wall means dividing said casing into a constant pressure chamber and a variable pressure cham ber, a valve port providing communication between the inlet and outlet ports and said variable pressure chamber, a reciprocal valve for cooperating with said valve port to control flow of fluid to said variable chamber, resilient means urging said valve toward closed position, said flexible wall means being flexible toward said valve to move the same toward open position when the pressure in said variable pressure chamber decreases below a predetermined pressure,

and a connecting member for transmitting flexing movement of said flexible wall means to said valve in a direction to open the same, said connecting member being disposed in said variable pressure chamber and having a plurality of resilient fingers engaging said flexible wall means to resiliently maintain engagement with the flexible wall means and valve.

3. An expansion valve comprising a body having a recessed and stepped wall providing an outwardly facing and continuous shoulder and having inlet and outlet ports, a diaphragm within said recess and mounted on said shoulder, one side of said diaphragm cooperating with the inner walls of said body providing a chamber, said chamber being in communication with said inlet and outlet ports, a valve port in said body providing communication between said inlet port and said chamber, a valve cooperating with said valve port for controlling flow of fluid to said chamber, said valve having operative connection with said diaphragm, means urging said valve toward closed position, a cap having an open side disposed toward the other side of said diaphragm and telescoping within said recess with its edge bearing on said diaphragm, there being a space surrounding said cap between the outer wall of the cap and the inner wall of the body, said cap and said diaphragm cooperating to provide a chamber for containing a gas under pressure operable to flex said diaphragm to open said valve when the force exerted by said gas in said secondnamed chamber exceeds the combined and opposing forces of said means and the pressure in said first-named chamber, and a sealing material disposed in said space between the cap and inner wall of the body for sealing said secondnamed chamber and for securing said cap to said body.

4. An expansion valve comprising a body hav-' ing a recessed and stepped wall providing an outwardly facing and continuous shoulder and having inlet and outlet ports, a flexible wall means telescoping within said recess and mounted on said shoulder, said wall means cooperating with the inner walls of the body providing a chamber, said chamber being in communication with said outlet port, a valve port in said body providing communication between said inlet port and said chamber, a valve for cooperating with said valve'port to control the flow of fluid to said chamber, said valve having operative connection-with said flexible wall means. a backing plate bearing against said flexible wall means and telescoping within said recess, said backing plate having an aperture centrally thereof in alignment with the center of said flexible wall means, a housing member telescoping within said recess and having an outturned flange bearing against said backing plate leaving a space between the outer wall of said housing member and the inner wall of the body, said housing member and said flexible wall means cooperating to form a closed chamber for containing a gas under pressure operable to flex said flexible wall' means and actuate said valve when the pressure in said closed chamber acting on one side of said flexible wall means exceeds the pressure exerted on the opposite side of said flexible wall means, and a sealing material disposed in said space surrounding said housing member for sealing said second-named chamber and for securing the housing member, backing plate, and flexible wall means to the body.

5. An expansion valve comprising a body having a recessed and stepped wall providing an outwardly facing and continuous shoulder and having inlet and outlet ports, a pan-shaped diaphragm within said recess and mounted on said shoulder with the side wall of the pan-shaped diaphragm extending outwardly from said shoulder; one side of said diaphragm cooperating with the inner walls of said recessed body providing a chamber, said chamber being in open communicationwith said outlet, avalve port in said body providing communication between said inlet and said chamber, a valve cooperating with said valve port for controlling flow of fluid to said chamber, said valve having operative connection with said diaphragm, means urging said valve toward closed position, a cap having an open side disposed toward said diaphragm and telescoping within said diaphragm with a space surrounding said cap between the cap and the inner wall of the body, said cap and said diaphragm cooperating to provide a chamber for containing a gas under pressure operable to flex said diaphragm to open the valve when the force of said means urging the valve toward closed position becomes less than the force exerted by said gas, and a sealing material disposed between the outer wall of the cap and the inner wall of said pan-shaped diaphragm and between the outer wall of said pan-shaped diaphragm and the inner wall of said body whereby to seal said chambers and secure said cap and diaphragm'to said body.

6. In an expansion valve, 9. body member'having a passageway therethrough with a valve port, a hollow housing member mounted on said body member and having its open side disposed toward a wall of said body member, said body member and said housing member having overlapping side wall portions in radially spaced relation to provide an annular chamber, a resilient closure member disposed between said body memberand said housing member and having a portion extending into said annular chamber, said closure member being subject to and movable by pressure in said passageway andfcooperating with said housing member to provide a closed pressure chamber, a valve member cooperable with said resilient closure member and controlling said port, sealing material in said annular chamber and directly engaging said closure member to hermetically seal said pressure chamber and to seal said resilient closure member to said body member, and an inert gas in said sealed pressure chamber and regulating the movement of said valve member by pressure in said passageway.

'7. In .a valve of the character described, a casing having a chamber with an inlet and an outlet, means responsive to and movable by pressure in said chamber, said casing having a valve port intermediate said inlet and said outlet, a valve member cooperable with said port and positioned on the opposite side of said port from said responsive means, a resilient supporting member seating against said responsive means, a thrust member carried by said supporting member and extending toward and engageable with said valve member, and means acting on said valve member to hold said valve member and said thrust member in engagement, said last-named means holding said supporting member under tension to oppose lateral-shifting of said thrust member.

8. In a valve of the character described, a casing having a chamber with an inlet and an outlet, means responsive to and movable by pressure in said chamber, said casing having a valve port intermediate said inlet and said outlet, a valve member cooperable with said port and positioned on the opposite side of said port from said responsive means, a resilient supporting member seating against said responsive means, a thrust member carried by said supporting member and extending toward and engageable with said valve member, said valve member and said thrust member having interfitting engagement to oppose lateral relative displacement between said valve and said thrust members, and means acting on said valve member to hold said valve member-and said thrust member in engagement, said lastnamed means holding said supporting member under tension to oppose lateral shifting of said thrust member relative to said responsive means.

9; In a valve of the character described, a casing having a chamber with an inlet and an outlet, means responsive to and movable by pressure in said chamber, said casing having a-"valve port intermediate said inlet and said outlet, a tapered valve member cooperable with said port and positioned on the opposite side of said port from said responsive means, a resilient supporting member seating against said responsive means,

a thrust member carried by said supporting member and extending toward and engageable with said valve member, said thrust member having an end recess receiving the tapered end portion of said valve member, and means acting on said valve member to hold said valve member end portion in said thrust member recess, said last-named means holding said supporting member under tension to oppose lateral shifting of said thrust member.

10. In a valve of the character described, a casing having a chamber with an inlet and an outlet, means responsive to and movable by pressure in said chamber, said casing having a valve port intermediate said inlet and said outlet, a valve member cooperable with said port and positioned on the opposite side of said port from said responsive means, a supporting member having radially extending resilient arms seating against said responsive means, a thrust member rigidly mounted on said supporting member and extending toward and engageable with said valve member, and means acting on said valve member to hold said valve member and said thrust member in engagement, said last-named means holding said supporting member under tension to oppose lateral shifting of said thrust member;

11. In a device of the character described, a body member having an open side and having a continuous seat portion facing said side, a flexible closure member having a peripheral portion seating on said seat portion, a housing member having a continuous side wall'portion extending'into and spaced laterally from said body member and seating on said flexible member, said closure member having a marginal flange portion extending substantially perpendicular from the plane of said closure member and extending between said laterally spaced wall portion and said body member, means surrounding said side wall portion and directly engaging each of and hermetically sealing and bonding together said marginal flange portion said body member and said housing member, and a control means operatively connected to said flexible closure member.

12. In a valve of the character described, a body member having an open side and a continuous seat portion facing said side, a diaphragm member seated on said portion and having a transverse marginal flange portion extending toward said side, a reenforcing member spaced from and engageable by said diaphragm member and having .a marginal portion seating on said diaphragm member and overlying said seat portion, a cap member having a side wall portion within said body member and seating on said reenforcing member portion, said body member having a valve port, a valve member cooperable with said diaphragm member and with said port to control flow through said port under control of said diaphragm member, sealing means be-' therethrough for transmission of the medium pressure to said diaphragm member.

13. In a valve of the character described, a body member having an open side and a continuous seat portion facing said side, a diaphragm member seated on said portion and having-La transverse marginal flange portion extending toward said side, a reenforcing member spaced from and engageable by said diaphragm member and having a marginal nortion seating on said diaphragm member and overlying said seat portion, said reeni'orcing member having an annular reenforcing rib adjacent said marginal portion, a cap member having a side wall portion within said body member and seating on said reenforcing member portion, said cap member side wall having a surrounding flange portion fltting between said rib and said diaphragm member flange 7 portion, said body member having a valve port, a

- the medium pressure to said diaphragm member.

14. An expansion valve comprising a solid body member having a head portion and having a pair of parallel passageways opening through one side of said member opposite said portion, said passageways comprising respectively a strainer 95 chamber and a valve chamber, a continuous flange projecting from said head portion opposite said one side and concentric with said valve chamber, said valve chamber having an annular internal shoulder facing said one side and forming a valve seat, a valve member in said valve chamber, a plug member closing and sealing the outer end of said valve chamber, a helical coil spring held under compression by said plug mem ber and urging said valve member to said seat, said body member having a passageway from the inner end portion of said strainer chamber to said valve chamber on the inlet side of said valve seat, a resilient diaphragm member extending across said head portion and bounded by said flange, means sealing said diaphragm member to said flange to provide a pressure chamber between said diaphragm member and said head portion, said valve chamber passageway opening into said pressure chamber and being concentric with said diaphragm member, and means operatively connecting said diaphragm member and said valve member, said body member having an outlet passageway leading from said pressure chamber so that said diaphragm member will act to move said valve member toward open position upon reduction of pressure in said pressure chamber communicated through 35 said outlet passageway.

DANIEL D. WILE.

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