US2667897A - Control device and valve - Google Patents

Description

Feb- 2, 1954 w. L. HUNTlNGToN I 2,667,8@7

CONTROL DEVICE AND VALVE Filed Dec. 27, 194s 2 sheets-sheet 1- Snoentor WILL/HN JIU/72711670 Feb. 2, 1954 Filed Dec. 27, 1948 W. L. HUNTINGTON CONTR OL. DEVI CE AND VALVE 2 Sheets-Sheet 2 i INVENTOR. WILLIAM L. HUNHNGTON H TTRNEY Patented Feb. 2, 1954 CONTROL DEVICE AND VALVE William L. Huntington, Minneapolis, Minn., as-

vsignor to .Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application December 27, 1948, 'Serial No. 67,454

(Cl. IS7- 620) 9 .Claims. 1

This application iis va continuation vin .part of v'application No. 749,493, lled May 21, 1947, which isnowabandoned.

The present invention lrelates :to .a control rdevice and control valve 'for fluid .motors generally and 'fordiaphra'gm gas'valves in particular. The device fis preferably `of the 'type that V'en'rloodies both :an automatic 7and .a manual control means for :actuating :the -control valve, and suitable mechanism actuated ,by the manual means that adapts the .device to automatically transfer to the automatic control meansJ .upon the `supply or" electrical power thereto. :The Vmanual control and transfer 4mechanism may .be omitted how ever. The control valves function is to :control the flow `of Vpressure :duid vfto and from a fluid motor .ordiaphragm valve.

:One r'of the objects ofthe invention is ito providegan inexpensive-control valve that is so easily operated that y'only a very lsmall amount of Vpovver is required itc actuate it, such as Ythe electrical power that may vbe developed .by :a small thermoelectric generator heated loy :a pilot flame, or h* a :battery or vby :any :other suitable means.

Another object of vthe invention is to provide a control val-ve that is :easy Yto assemble and repair.

Another fobieotiis to provide a :control Vvalve that is pressure balanced.

Another object is to provide la Vpressure bal- Y anced valve that Will not open when there is a leak therein, thus providing a signal that a leak is present that should be iixed.

An .additional object ci the `invention is toiprovide a diaphragm pressure 'balanced valve with an aperturcd cover that normally tends to tmain tain atmospheric pressures in said cover; .but the aperture therein being of such size that [a rupture in ysaid diaphragm will cause the cover` to assume substantially valve pressure, thus cancelling the balancing veffect of the valve so `as to prevent lnormal opening of the valve 'by its power means. A further object of my invention is to provide a. contro-l device of the :alcove noted type wherein the automatic and manual means for actuating the control valve cooperate in asimpler and more emcient Way thenv the prior art arrangements.

Still further' objects and advantages :of the invention will become apparent upon reading the following detailed description .of .the .invention in conjunction with the yaccompanying sheet of drawing wherein:

Figure l is an elevational View of the control apparatus with the cover shown in rcross-section.; Figure 2' is a cross-sectional view taken along they longitudinal axis of the valve;

Figure 3 iis a cross-sectional view taken 'along the Aline '3-3 `inl'igure 2;

Figure et is a fragmental vievvfof lavalve similar to that shown in Figure 3, but showing a slightly modified arrangement of the valve parts;

Figure 5 is a schematic Wiring diagram of the control system;

'Figure 6 is an lelevational View .of Vanother modication of the invention `vvith parts thereof shown in cross-section and parts broken away; Vand Figure '7 is a plan 'view of the cover shown in cross section in Figure 6, `with its cap removed.

The illustrated. embodiment of the control unit of the system shown .inFigure 1 comprises 'a control valve, designated generally by the `reference numeral 1, and an electric relay, :indicated generally at 2, both mounted on van :adapter base plate 2s, and `a manual controller indicated generally at t.

The details of `the valve can voest :be seen in Figure '2. It comprises 'a main `body portion `5 having an elongated chamber 18 therein open 'at its top, three opening-s "'l, 8 and i9 'in the zbottom thereof, vancirecesses it and EH in the upper edge thereof. Opening 'l :connects chamber vt With conduit l2 in the .adapter plate J3, Awhich 'conduit is connected Ato a source of '-iiuid under pressure. Opening E8 `extends .from the side wall of opening 9 to connect said opening S with conduit I3 in the adapter 3, which conduit is adapted to 1he @connected to the fluid motor that is desired to the controlled, such as the diaphragm valve shown at -35 in the .McGoldrick Patent No. 2,304,268. The fluid motor or diaphragm valve forms no part oi this invention and is, therefore, not illustrated. Opening l9 extends from Ycl'iarnh-er S to 'conduit la in said adapter 3,- which Vconduit forms an :exhaust or bleed' to the atmosphere or any suitable low 'pressure area. The lopening vi) also has the ,intermediate .portion of its length of reduced diameter forming shoulders i5 therein `neareachzen'd thereof.

Mounted in the above mentioned :opening 8 in the valve body, are tivo telescopic valveseat memhers .it vand `Il suitably secured together as by screw threads so as .to .have portions thereof rest on vthe above mentioned shoulders l5. The member le has .a valve seat opening is and an opening 2d in the side Wall thereof in communication with the opening `Si in the valve body 5. The member Il has a valve seat opening 19, of the same diameter as .opening i3, in communication with the conduit I4 in the adapter 3.

Positioned between the valve sea-t openings i8 and 1S is a ball valve L21 having a stem 22 extending upwardly through opening I6.

Mounted in the recess i9 of the valve body is a Washer 23. A plate 24 clamps a sheet of flexible material 25, such as rubber or the like, down against the top edge of the valve body 5 and the washer 23.

An arm 26, having pivots 21 formed on one end thereof, is mounted in the chamber 6 with the pivots 21 in the recesses I under the washer 23. The other end of arm 26 is bifurcated at 29 and engages in an annular groove in the valve stem 22. A stem 28, which has one end connected to arm 26 near pivots 21, extends through a small opening in the exible member 25 and through an opening 3| in the plate 24, the opening 3| being of substantially the same diameter as the opening in the washer 23. The area of the opening 3| is of such size that the force of the fluid against the bottom of the stem 28 and the iiexible member 25, multiplied by the distance between the longitudinal axis of the stern 28 and the axis of the pivots 21, equals the moment of force about the pivots axis due to fluid pressure on the top of valve 2|. This latter moment of force is equal to the transverse area of opening I8 multiplied by the distance between the longitudinal axis of the valve stem 22 and the axis of the pivots 21. It is thus seen that no matter what fluid pressure exists in chamber 6, the uid force on the valve is balanced by the fluid force on the flexible member 25 and the bottom of stem 28.

The angle through which the pivots 21 must rotate is very small due to the fact the valve movement is very small. However, it is desirable that the top and bottom surfaces of the pivots be rounded somewhat to permit easy rocking thereof. It is to be noted that the ring 23 serves the dual function of an upper bearing surface for the pivots and a transverse support for the central portion of the fiexible material 25. The removable cover 24, flexible material 25, ringY 23, pivots 21 and sealing means 39 and 40 thus provide a low cost and easily repaired valve assembly.

The stem 28 has a beveled shoulder 32 near the lower end thereof and below the member 25 and a screw-threaded upper end. Mounted on the upper end of the stem 28 are two opposed actuating arms 33 and 34 clamped between abutment members 35 and 36 locked in position by washer 31 and nut 38. Slidably mounted on the stem 28 between the member 25 and the abutment member 35 is a cup-shaped clamping member 39 and a spring 48. The flexible member 25 is thus clamped between member 39 and the shoulder 32 on the stem 28 to form a fluid tight seal.

The arm 34, which has a struck-up friction reducing member 4| thereon, is flexible to provide a strain release enabling the arm 34 to continue its movement upwardly after the valve 2| has seated and closed the opening I8. The necessity for such a strain release will be explained hereinafter. The arm 33 is comparatively rigid and also has a struck-up friction reducing member 42.

Referring now to Figure 1 of the drawing, the power means for moving the arms 33 and 34, namely, the relay 2, comprises an electromagnet 43 having arcore 44, an armature 45, a pivot member 46 and a spring 41 secured at one end to the pivot member 46 and Yat the other end to the armature 45.

The armature is pivoted near its center with one end thereof positioned between the members 4| and 42 on arms 34 and 33, respectively, and the other end thereof is positioned over the core 44.

Mounted on the armature between suitable insulating spacer members 48 and 49 is a switch arm 50 adapted to engage a fixed contact member 5|. Also mounted on the armature 45 is a stiff spring latching member 52 having a detent 53 with all of the above mentioned elements mounted on the armature on the relay side of the pivot 46, it is obvious that the sum of their moments of force are equal to, or exceed, the sum of the moments of force (exclusive of the tension of spring 41) acting in the opposite direction on the valve side of said pivot 46. With this balancing of the masses of the pivoted members, it is apparent that drop-out and pull in forces of the relay armature will be constant and regulated solely by the tension of spring 41.

Pivotally mounted to a frame member 54 by means of a pivot 55 is the manual control member 4 having an arm 56 with a finger grip end 51 extending through an opening in the casing 58 and having cams 59 and 69 extending radially from the pivoted end thereof. A torsional spring 6| anchored at one end in the frame 54 and at the other end in cam 59, is so strained that it tends to rotate the arm 56 and cams 59 and 69 in a clockwise direction.

Also pivoted to the frame 54 is a switch arm 62 Yadapted to engage fixed contact member 63.

Referring now to the schematic wiring diagram of Figure 5, a bimetallic thermostat, generally designated by the reference numeral 64, comprises a flexible contact arm and a comparatively rigid contact arm 66. The contact arm 65 is adapted to engage fixed contactr61 before contact arm 66 engages fixed contact 68. The other endof the thermostat is connected through line 18 with fixed contact 5I.- A source of electrical power, generally designated by the reference numeral 1| is illustrated as being a transformer but, it is to be understood, said source may consist of a thermoelectric generator or a storage battery or any other suitable source of electrical energy. Terminal 12 of the secondary of said transformer is connected through line 13 to the fixed contact 61 while the other terminal 14 of the secondary is connected to terminal 15'of the relay 43. The other terminal 16 of the relay is connected through line 11 to the fixed contact 68. The switch arm 50 is adapted to complete a circuit from line 10 through contact 5| to line 11 while switch arm 62 is adapted toV complete a second circuit from line 13 through contact 63 and line 18 to line 11.

Operation With the elements of the apparatus in the position shown in all the figures of the drawing, fluid under pressure is being delivered through conduit |2, opening 1, chamber 6, opening I8, opening 8 and conduit I3 tothe iiuid operated motor. The ball-shaped valve head 2| is held seated against the opening I9 solely by the action of the spring 41 inasmuch as the fiuid pressure acting on the ball valve head is counterbalanced by the fluid pressure acting on the flexible wall 25. Now, assuming that a condition arises calling for'the release of pressure to the pressure motor and calling for the contact arms 65 and 65 of the thermostat 64 to move toward the left, it is readily seen that nothing will happen when contact arm 65 'engages fixed contact 6'1 due to the open circuit at 50 and V5|. VWhen contact arm 66 comes into contact with fixed contact 68, a circuit will be completed lfrom the secondary terminal 12 of the transformer through line 13,

fixed contact 61, contact arm 65, contact-arm 66, fixed contact 63, line 11, terminal 16, relay.,

43, terminal and terminal 14 at the other end of the secondary. This will cause relay 43 to become energized drawing the arm down against the core 44, lifting of valve end 2I to seal opening I8 and unseal opening I9, and bringing contact arm into engagement with xed contact 5I and, thereby, completing a holding circuit. This holding circuit extends from line 13, Xed contact 61, arm 65, line 10,'contact 5I and arm 59 to line 11, in parallel with the circuit from contact arm 65 through contact arm 66, iixed contact 69 and line 11. With the control elements in this position, the fluid under pressure in chamber 6 will be unable to flow through opening I8 but the fluid under pressure in the pressure motor is free to bleed out through conduit I3, opening 8, opening 20, opening I9, and conduit I4 to the atmosphere or a low pressure area. If the pressure motor were a diaphragm valve of the type mentioned above, the valve would now be in its open position. It is to be noted that, here again, the force tending to move the valve head 2| downwardly is counterbalanced as described above. It is therefore apparent that the spring 41 causes movement of the valve in one direction upon deenergization of the relay 43 and that the relay only has to overcome the force of said spring 41 to cause the valve to move in the other direction.

Now, should the condition reverse, requiring that the thermostat arms 65 and 66 move toward the right and that pressure be supplied to the pressure motor, it is seen that nothing will happen when contact arm 65 separates from xed contact 61, due to the holding circuit still being closed. However, when contact arm 66 leaves fixed contact 68, the circuit through the relay will be broken permitting the spring 41 to raise the armature off of the core 44 and to move the valve head 2I against opening I9. This will permit the ilow of fluid to again build up the pressure in the pressure motor and, in the case of a diaphragm valve, to close said valve.

Should there be a power failure or should it be desired to operate the pressure motor regardless of the position of the contact arms and 66, it is possible to move the valve head 2I from opening I9 to opening I9 by moving the end 51 of manual control lever 56 to its lowermost position. In moving said end to its lower position, the cam 59 will engage spring 52 and move it and the armature 45 downwardly to a position wherein the armature 45 is slightly spaced from the core 44 but the valve head 2l is seated on opening I B. Also, as said end is moved downwardly, the cam engages and moves contact arm 62 into engagement with fixed contact 63 closing a shunt circuit around the thermostat from line 13 through contact arm 62, contact 63 and line 18 to line 11. Thecam 59 holds the manual lever 53 in its lower position against the action of spring 6I by engaging in detent 53 in the spring member 52. The valve head 2l obviously may be moved in the other direction by manually moving the end 51 upwardly or it mayV be returned to the control of the thermostat upon the initial supply of current or resumption of current supply. Irrespective of the position of contact arms and 66, upon the supply of current to the device, the relay 43 will become energized and draw the armature 45 the rest of the' way to engage core 44 and thereby release cam 59 from detent 53 permitting it to move upwardly and disengage contact arm 62 from xed contact 63. The continued movement of the armature downwardly against the core 44 is permitted.

by the strain release action of flexible arm 34 mentioned above. It is to be noted that contact arm 32 is moved only upon movement of the manual control lever 56.

The valve modification shown in Figure4 discloses a valve body 5a which is similar to the valve body of Figures 2 and 3. The dierences between this modication and the one shown in Figures 2 and 3 lies in the shorter length of the arm 26a and body 5a', the position of the stem' 28 on the arm 26a, and the position of the small opening in the flexible member 25a throughv which the stem 38 passes. It is to be noted that in Figure 4 the stem 28 is centered on theaxis of the pivots 21 and spaced from the center --of the washer 23 and opening 3I in the member' 24 while, in Figures 2 and 3, the small opening in the member 25 and the stem 28 is centered with respect to the washer 23 and opening 3|.

and spaced from the axis of the pivots 21. The Figure 4 modication relies upon the unbalanced areas of the diaphragm for rocking the arm 26 in valve balancing direction. The larger area of the flexible wall 25 -to the left of the' pivots axis will exert a greaterpull on the left member 25 to the right of said pivots,'due to the fluid pressure acting on said portions. view of the fact that the resultant moment of force tending to rock the valve clockwise about pivots 21 is obviously less, for any given pressure, than the rocking moment lfor the valve of Figure 2, the effective length of arm 26a (Figure 4) must be shorter than that of 26 (Figure 2) to balance the moment of force tending to rock the valve of Figure 4 counter-clockwise due to uid pressure on said valve. The structure and operation of the valve of Figure 4 is otherwise the same as that of Figure 2.

Modification plate 24.y The relay 2b is substantially the same The base' plate 3b is slightly dierent from the base plate 3 of'Figures 1 through 3 but has passages thereas the relay 2 of Figures 1 through 3.

in (not shown) for communicating with the passages 1, 8 and I9 in the valve body 5 which is' identical with that shown in Figures 1 through.

Valve Ib and the relay 2b, along with its asso-y ciated armature pivot member 4Gb, are securedI to the base plate 3b by any suitable means,

in the modication of Figures l through 3.

The armature 451) does not carry insulating spacer members, such as those shown at 42 and 49 in Figure 1, as this modication does not provide for manual actuation of the armature and,

therefore, does not require control meansY forl transferring the device froml a manual control to the automatic control. 33h and 34h engage the right hand end of the armature 45h as in the modication of Figures l' through 3.

In order to provide means to prevent the escape of fuel into the surrounding atmosphere, if thev diaphragm 25 should become ruptured, which' would create an undesirable if not a dangerous' condition, the casing 58his provided. This cas- The valve actuating arms ing: has a. sealing .partition 15.: extendingv .transversely across thel interior of: said casing inter mediate itsend; The partition lo is apertured at'v 80: toprovide for' the passage kof lead wires from the relay to a terminal; block.' Sir. The terminalblocir is made'of: insulating material and issecured' to theY partitionze 'by' means of screws Bthreaded into tappedholesz in the-partition. Bead; terminalsv 84,I are adapted to releasably clamp? leadt wires (not. shown) from a suitable power'source and are connected tothe lead wires from thefrelay. 2o at their lower ends. To prevent leakage'. of gas through the openingO 8o, a gasket-.'85 is clamped between terminal block 3i andfthenpartition 19.

Averysmall (pin-hole) opening Bt, 'approximately' 0.0312 of an inchiin diameter, is formed through the partition 19. This opening is to prov-idei'for very :slowy passage of gas or air into andor out. ofthe space below the partition i9. This enables. the pressure said lchamber or space-tolse thesame as the" pressure (normally atmospheric) inthe-chamber above the partition 19, .provided there'is no rapid now of uid'under relatively high pressure into either one of said chambers. Opening 8l' is provided inthe side walliof the-.upper chamberto provide for the pas sage Ofsaid-pOWer lead-lines to the. terminals 84.

A- cap 8%, carrying a nameplate 89, has downwardly extending flanges which frictionally hold the capcver the top of the casing 58h, but does not seal the opening: 81. The housing is secured tothe top surface-of thefplate 3b, with a sealing gasket. 90)*l therebetween,` by meansof bolts 9i passing. through bores 92 in the. housing and through alignedbores (not shown) in the base plate 3b.

'Operation The. operation. of the modification of Figures 6 and 7 differs from that. of Figures. 1 through 5 in that as no holding circuit is used with this modication, a two Wire, single contact room thermostat may be used to control the flow of current from a thermopile or other source of x. power tothe relay 2b. Otherwise, the` operationA of the control valve and its actuating relay isthe Valveactuating lever 26 to hold the valve 21 in.

its closed positionf even though the relay were energized and there were gas pressure under said diaphragm tending to open said valve. The necessityfor the opening 86is therefore apparent. By making the opening 86 no larger than is absolutely necessary, a safety feature is provided which. provides a dual function. Should the diaphragm 25 become accidentally punctured, or the valve body cracked, so as to permit fairly rapid escape of gas from the chamber 6, the small opening 86 would prevent said escaping gasfrom entering. thesurroundng atmosphere of thecontrol. device at .a rate. which would create a dangerous condition either .from the standpoint ofexplosion or inhalationof the gas by people or animalsa While; the worstipartgof thevpresenc of. escaping gasis. thusovercome', it .ishighlyf-fdesirable that no gas beipermittedzto escapefrom the standpoint of. economy. Therefore, a;sec ond functionA of; providing a" suitable signal `to the operator or'householder that a leakisv pres ent, is' provided by the failure ofthe control valve to open and supply; fuel. to the' fur-nace when there is a demand for heat. The operator or householder, noting that. the temperature of the space being` heated. by the furnace' has dropped below the normally maintainedtemperature, will obviously' know that thereis improper furnace operation. This of :course will *leadv to the correction' of thedifficulty.

While the safetyushutdown of. theV furnaceand.4 the escape ofi gas.' tothe atmosphere 'hasVV been described: only with respect to the simplerrelay operated. control valve of'Figures 6. and 7, it; is t0 be understood that the-'same principle of'- 0perati'on could be. applied to the'modificationsof Figuresl l through 4?. Thatti's, by simply making the terminal block 5G' of Figure 1in. the'formz of a sealing partition between the spacev abovezand below saidfblock and bysubstituting aneXter-iorally disposed cranktype of actuating arm `for the cams 5o and' .5t andi extending the-crankar-ms shaft 55 vthrough thewall ofthe casing for securing saidcrank type of. manual actuating lever,v and by eliminating the' .lever .56; andthe slot-1 in the casing through whichitextendaandfby'pro viding asrnall openngithrough the t'erminalblock Eri similar to the opening 861m Figures 6 andr',

ie modificationsr of Figures 1 throughil would operate in the same: manner as that' of Figuresi and 7. Of course thecasing 58 would have to be sealingly connected to the^base plate. 3.

it will be apparent. fromi the above. description of the preferred embodiments 'of this invention' that a veryfsimple, easilyoperate'd; yini-expensive and efficient cont-rol device and valve is provided that permits both automatic and manual control of a pressure motor and whichV provides a'simple arrangement of parts that enables ank automatic return from-the manual control'to the automatic control upon thefresumption of. the power supply to the device. Furthermore,.the device provides asimple safety casing constructionrthat prevents dangerous quantities of gas fromescaping to the atmosphere, should a break occur in a valve'wall, and Vprevents the. furnace-from' operating,l tofserve as a signal of'said break.

It willalso-be apparent to those skilledin the artA to which this invention apertains that numerous changes in construction and designf mayV be made therein without departing from'thesp'irit` or scope of the invention. It is, therefore, to be understood thatthegscope ,of the invention vis not to be limited by the' particulardisclosure but only by theappended claims.

I claim:

l. A control device comprising a hollow body having an inlet and an outlet and a flexibler exl terior wall portion, avalve seat betweensaid inlet and outlet, a valve member, a pivoted lever connected to said. member and extending through and securedv to said'iiexible Ywall portion at a point that ycauses. the fluid; pressure on said' portion to substantiallyv counterbalance the same pressure aetingon saidivalve member'in an opposite direction, arms mounted: in opposed' relationship onone: end fof said lever, one of said arms beingresilient'soyasto enable further movement ofa portion thereof-bevanda positionwhere`v said valve seats, a pivotedpowerarm having'one end thereof positioned between said arms, manually operable means disengaged from said power arm but movable to actuate said power arm a distance sufficient to move said arms to said position, power means adapted to actuate said power arm beyond said position, and means on said power arm cooperating with said manually operable means to hold it in said position but adapted to release it to its disengaged position upon actuation of the power arm by said power means.

2. A pilot valve for a fluid motor comprising a valve body having an inlet and an outlet, a three-way valve between said inlet and outlet having spaced apart and opposed valve seats and a constantly open passage terminating between them, a valve head positioned between said seats and having a stem thereon extending through the valve seat at the inlet side of the three-way valve, said Valve body having a exible Wall portion, an actuating lever extending through and connected intermediate its ends to a central part of said wall portion and connected at one of its ends to said valve stem, said lever being pivoted to said valve body at a point where the distance from said point to said central part o said wall portion times the area of said flexible wall portion substantially equals the distance from said point to said valve stem times the fluid pressure area of said valve head, which enables inlet uid pressure on said iiexible wall portion to substantially balance the force acting on said valve head by the same fluid pressure so as to aid the moving of the valve head against said pressure.

3. A pilot valve as defined in claim 2 in combination with a cup-shaped casing having a pin hole opening therethrough, said casing being sealingly secured to said valve body so that there would be no rapid flow of iluid from said valve to the atmosphere should said flexible wall portion rupture destroying the balancing action thereof on said valve.

4. A valve comprising a Valve body having an inlet and an outlet, a valve seat between said inlet and outlet, said body having a movable wall portion on the inlet side of said valve seat, a valve head cooperating with said valve seat and being urged toward closed position thereon by inlet :duid pressure thereon, and a lever operably connected at a irst portion thereof to said valve head and pivotally connected at a second portion thereof to the valve body on the inlet side of said valve seat and connected at a third portion thereof to said movable wall, the length of said lever from its pivotal connection with said body to said Valve head times the pressure area f said valve head being substantially equal to the pressure area of said movable wall times the distance from its connection with said lever to the pivotal connection of said lever with said body.

5. A valve as dened in claim 4 in combination with a housing extending over said movable wall portion and sealingly connected to said valve body, said housing having a pin hole therethrough to provide restricted uid flow between the interior and the exterior of said housing.

6. A valve comprising a hollow open-top body having an inlet and an outlet and a partition wall between said inlet and outlet, a cover therefor having an opening therein, a sheet of exible material clamped between the open top of said body and said cover, a passage through said wall, a valve seat in said passage, a valve head having a stem thereon extending into the interior and the supply side of said body, and an actuating lever extending from said stem through said material and pivoted on pivots in said body, the point at which the lever passes through the flexible material lying between said stem and said pivots and the area of said iiexible material over said opening times the distance between the center of said opening and said pivots being substantially equal to the area of said valve head times the eiective length of said actuating lever.

7. A valve as dened in claim 6 in combination with a housing sealingly covering the opening in said cover from the atmosphere, said housing having a pin hole therethrough for restricting fluid flow between the interior and the exterior of said housing.

3. A valve comprising a hollow open-top body having an inlet and an outlet and a partition wall between said inlet and outlet, recesses in edges of said open top, a cover having an opening therein, a sheet of flexible material spanning said opening, a passage through said wall having a valve seat therein, a valve head cooperable with said seat and having a stem extending into the interior of said body, and an actuating lever extending from said stern through said material and pivoted on pivot means in said recesses and inwardly of said material, the point at which said lever passes through said material lying between said recesses and said stem, said lever having an 'annular shoulder thereon on one side of said material and a spring pressed washer thereon on the other side of said material for resilently clamping said material against said shoulder and the area, of said flexible material over said opening times the distance between the center of said opening and Said pivots being substantially equal to the area of said valve head times the effective length of said actuating lever.

9. A valve as dened in claim 8 in combination with a housing sealingly covering the opening in said cover from the atmosphere, said housing having a pin hole therethrough for restricting uid flow between the interior and the exterior of said housing.

WILLIAM L. HUNTINGTON.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 381,055 Creelman Apr. 10, 1888 927,593 Phillipson July 13, 1909 1,716,377 Grant June 11, 1929 2,004,417 Penn June 11, 1935 2,011,220 Henning Aug. 13, 1935 2,110,326 De Lancey Mar. 8, 1938 2,122,398 Harrison July 5, 1938 2,163,132 Roney June 20, 1939 2,265,294 Lange Dec. 9, 1941 2,358,999 Ray Sept. 26, 1944 2,496,638 Ray Feb. 7, 1950

Images