US2505663A - Means for draining accumulated moisture from storage tanks - Google Patents

Description

MEANS 'OR'DRAINING ACCUMULATED MOISTURE FROM STORAGE TANKS. Filed March l, 1946 PRIH 25 1950 R c cHURcHMAN 2,505,663

Patented Apr. 25,i 1950 NITED STATES DFFICE MEANS FOR DRAINING ACCUMULATED MOES'URE FRM STORAGE TANKS Application March 1, 1946, Serial No. 651,261

11 Claims.

This invention relates to means in combination with a compressor unit and storage tank to drain any accumulated moisture from the storage tank and more particularly is an improvement over Patent 2,330,027 issued September 2l, 1943, oi which applicant is a co-inventor and pending application Serial No. 625,225, illed October 29, 1945, of which applicant is the sole inventor.

One problem in compressing air and storing the same is a change in the equilibrium conditions of the original atmosphere. The moisture content, present in the atmosphere as a vapor, drops out of the air as a liquid upon increased pressure and is present in the bottom of the storage tank. If the moisture is not drained from the storage tank, it continues to build up, cutting down the capacity of the storage tank for compressed air, and it passes out with the compressed air and creates trouble; for example it has a corrosive eiect on any metal parts contacted and dilutes any material sprayed, such as paint. Petcocks on the bottom i storage tanks have been provided to manually drain any accumulated moisture from the storage tanks but they have proved ineiective in that operators neglect attending to this chore.

It is an object of the invention among others to provide means in combination with any type compressor unit and storage tank to automatically drain accumulated moisture from the storage tank.

It is another object of the invention to provide means in combination with an unloader tank of a compressor and storage tank to automatically drain accumulated moisture from the storage tank after the compressor stops.

It is still another object of the invention to provide means in combination with a compressor unit of the type not having an unloader tank;

and a storage tank to automatically drain moisv ture from the storage tank at some period during the operation of the compressor unit.

It is a still further object of the invention to provide means in combination with a compressor unit of the type not having an unloader tank; and a storage tank to automatically drain moisture from the storage tank for a predetermined time interval at some period during the operation of the compressor unit.

It is a still further object of the invention to provide a means automatic in operation which is economical to manufacture, durable and efficient in use, easy to install and maintain and easy of adjustment. The means is further adaptable to be placed on new compressor units 2 or may be installed on compressor units already installed. Other objects will become apparent from a, detailed description to follow in conjunction with the drawing.

In carrying out the objects of the invention there is provided a compressor unit connected to a storage tank with the compressor unit maintaining pressure in the storage tank at a predetermined pressure. A check valve is placed between the compressor unit and storage tank. Means are provided for draining accumulated moisture from the storage tank comprising a valve structure in the combination with the valve structure having a housing. An inlet connects with the bottom of the storage tank and housing with an outlet leaving the housing to a point of disposal and said outlet located above the inlet. The inlet and outlet are connected by a passage in the housing which may be a vertical passage having a valve seat on top of the vertical passage. A valve member is seated on the valve seat with the valve member being attached to a piston movable within the housing above the valve seat. Spring means act against the piston to hold the valve in seated position on the valve seat against pressure from the storage tank and a source of fluid pressure enters the housing below the piston at intervals to raise the piston and in turn, the valve on? the valve seat to drain accumulated moisture from the storage tank. The source of iluid pressure enters the housing into a chamber above the valve seat and sealed from the inlet, vertical passage and outlet with the said valve member attached to a rod extending through a seal between the chamber and inlet, vertical passage and outlet and sealed therewith. The rod is attached to the piston which is movable within the chamber. There are also means connecting with the chamber in the form of a restricted outlet passage from the chamber to regulate the time interval that the valve remains open.

As one species of the invention, there is provided a compressor unit having an unloader tank and connected to a storage tank with said compressor unit maintaining pressure in the storage tank at predetermined pressure. An electric switch is included for starting and stopping the compressor unit while a check valve is mounted between the compressor unit and storage tank. There are means for draining accumulated moisture from the storage tank comprising the same valve structure as described previously. There is a relief valve connected with the electric switch which controls a conduit leading from the unloader tank to the valve structure with said relief 3 valve being closed when the electric switch is closed and open when the electric switch is open. The source of fluid pressure to operate the valve structure cornes from the unloader tank when the compressor stops, in this species.

In a second species there is provided a compressor unit connected to a storage tank with said compressor unit maintaining pressure in the Storage tank at a predetermined pressure. An electric switch is included for starting and stopping the compressor unit. There are means for draining accumulated moisture from the storage tank which comprises the valve structure previously described connected to the bottom of the storage` tank. A conduit is connected into the storage tank to deliver a pressure fluid from the storage tank to the valve structure. An electrically actuated valve is mounted in the conduit to ycontrol flow of pressure fluid in the conduit. The valve in the conduit is controlled by an electrical actuation means which electrical actuation means is connected electrically with the electric switch. The electrical actuation means is only operable to actuate the valve in the/conduit when the electric switch is closed with said electrical actuation means operating soon after the compressor starts into operation for a predetermined time interval and said valve in the conduit being opened only once each time the compressor unit operates. The said conduit 'dem/ers the pressure uuid to the valve structure to open the valve structure and` allow accumulated moisture from the storage tank to drain through thel valvek structure when the electrically actuatedv valve inthe conduit is opened. The electrical actuation means is automatically reset to operate again each time the compressor unit stops. y

With the foregoing andv other objects in view, the invention will be more fullyV described hereinafter and will be particularly pointed out in the claims appended hereto. v y

In the drawings, wherein like symbols refer to like or corresponding parts throughout the several views: y Figure l isA a diagrammatic view showing the combination 'of fa compressor unit, storage tank, and valve structure with the compressor unit including unloader tank.

Figure 2 isa diagrammatic view showing the combination of another type compressor unit, a

storage tank, valve structure and electrical actuation means to `operateV a valve in 'a conduit connecting the storage tank and valve structure.

Figure 3 is sectional view of the valve" structure with th'evalve member shown in elevation.

Figure i is a sectional viewt'aken on line 4--4 of Figure S'with part ofthe valve structure housing shown in elevation. 4 o l Figure 'l of the drawing indicates a crankshaft housing Iv connectediwithfa compressor 6 through conduit 2l and check valve 3 with a storage tank il. The compressor jI5 is connected to an electric motor s and 'said compressor I operated Ain the usualV manner by the 'motor 5'. The compressor 5, crankshaft housing I Iand motorl '5 along with va switch I makeup afcompressorunit. The com'- pre'ssor 5- has an uploader tank in the form of conduit 2 connected therewith which conduit 2 receives compressed air from the compressor "6 for passage to lstorage tank 4; Y

In the operation 'of the compressor unit, the storage tank E containing compressed air is conn'ectedV withmeans for using- 'the compressed air. The maximum pressure on the air in. storage tank is maintained 'at-sayf125. pounds perV square for this feature.

inch. When sucient air has been used from' storage tank fs to reduce the pressure in the storage tank to say 90 pounds per square inch, electric switch 7, which is connected into storage tank i (not shown) and actuated by the pressure of fluid in storage tank d, is closed. Switch 'I is connected to rnotor 5 (not shown)rv and when closed, allows electric current to flow to motor 5 and thus start motor 5 into operation. Motor 5 is not of a sufficient over-size to start into operation against 90 pounds per square inch pressure, hence the compressor E empties into conduit 2 which in the present embodiment is an unloader tank. rlhe pressure in the unica-der tank or conduit 2 builds up'V gradually; until it exceeds the pressure in storage tank il when check valve 3 opens and allows theair under pressure from conduit 2 to flow into storage tank 4. The compressor unit will operate until the pressure in the storage tank li reaches the maximum pressure for which the switch l is set. When this point is reached, the pressure fluid in storage tank 4 will exert its pressure on electric switch l to open the switch and cut on supply ofr electric power to. motor 5. The

* p essure fluid in storagetank 4 holds check valve 3 seated and the opening of switch 1 also opens a relief valve el which allows conduit 2` to be eX-t hausted and pressure in conduit 2 established at atmospheric so it will not be necessary for the compressor unit vto start upV against a pressure head. The operation` of the compressor unit with the unioader tank is the same as for units now on the market and beingl onered for sale commercially and applicant lays no claim to novelty The relief valve 8, through which the fluid under pressure from conduit 2 flows connects into conduit 9 which conduit ine drained. The housing lhas an outlet I3 leading to a point of disposal-for the accumulated moisture 'and a passage Ifl in the housing, which may be aV vertical passa-gato 'connectthe inlet i2 and outlet le to make a vconduit through the housing. The passage is. has a valve seat-`I5 'on top of the passage I5 and within the housing and a valve stem I6 on seat I5 to clo'se of'passage I. The valve stem I5 is connected to 'a piston Il' which is reciprocal within 4a c'zharnber I8 in housing member Il andra 'spring IiSfaCts aga-inst a piston Il to force it downwardly and in turn, keep the valve stem l5 seated on valvef'seat T5. The conduit 9 connects into chamber i3 through an en*- tr'ance 25 i-n housing l! to deliver pressure yfluid i; from -conduit 2 'when-.relief valve t is open. The

pressure fluid entersunder piston Il rtending 'toforce piston :Il upwardly v:against spring 'IQ 'thus' i is lift'edoi val'vefseat I'5'Canfbe vcontrolled by the time recuiied to 'exhaust `chamber IiI of Ypressure fluid. The chamber lil-is sealed from inlet I2, passage vIll and outlet :I3-'by rne'ansof gasket 24 and valve stem -'I 51 also passes throughfgasket 2R- a'nd`v is sealed therewith. A'nfopening' 25 :is pro- 'vided in the` top, of housing l; lto allow anyI prese sulla iluid that leaks by piston Il to pass out to theA atmosphere.

It is. noted that valve stem I6 seals against the inlet end l2 and passage i4 only, hence the valve stem Iii is sealing against pressure from the` store age tank l at all times. The accumulated moisturevfrom storage tank il, carrieswithit dirt, grease and all kinds of matter in suspension hence it is` extremely easy for any valve` controlling the inlet end of` a valve connecting with a storage tank to clog. The present valve stem` structure receives the full force of pressure from the storage tank 4l which in turn has a cleansing action on the valve. stem end, keeping it clean which allows it to` seat on the valve seat la and close off flow at all4 times. The passage t4: is madeabout onequarter inch in diameter while the spring is calibrated to exert. a pressure of approximately twenty pounds per square. inch, which allows approximately aY i6 to l ratio in opening. The pressure of uid in storage. tank- 4 never reaches a point where it can lift valve stem I6 oil valve seat i5. against the force of spring I9 over the greater area of piston il. Pressure fluid entering chamber i8 exerts a greater pressure than spring IS over the same area hence pistonY Il is raised;

in Figure. 2 is disclosed a compressor` unit, differing from the compressor unit of Figure l only in the instance that it hasno unloader tank in conjunction with the compressor. As in Figure 1 the crankshaft housing is represented at l with a conduit 2 connecting a compressor B-to storage tank i through a check valve 3. A motor 5 operates the compressor 6 and is ofsuillcient over-- sizeto start compressor Sinto operation against pressure of fluid in storage tank `il; An electric switch 'l controls operation of the compressor unit just as previously described for Figure l. A conduit 9, in the present instance, connects into storage tank iv above the level of any accumulatedioisture instorage tank ll` and delivers pressure uid from storage tank 4- to valve structure I0; to actuate the valve structure IiiV as previously described for Figure l where pressure fluid was l taken from conduit 2. The valve structure IU; used in Figure 2 is the same structure asemg-` ployed in Figure 1 with this one exceptiompthe adjustment on exhaust outlet 2l is not essential as it can` be left fully open.

AMounted in the conduit @is a Valve26- to control l'iow through the conduit 9 with the valve` 2E being opened by an electrical actuationmeans, shown generally at 21. The valve 2li-has a spring means within the valve (not shown) to keep the valve in closed position when the valve isv not` actuated by electrical actuation means 2T.

The electrical actuation means connects into switch 1 by conductors running from the same lead posts that connect to conductors running-` to the motor 5. In the drawing at Figure 2, the switch is shown as open but when the switch is'closed, electric current will mntoboth the-i4 motor 5 and electrical actuation `means 2?. Electric current flows nrst to a heating. element. shown diagrammatically at 28, Whichis aibutton.A type `flasher or circuit breakeriof-either 60er 100;A Thisv isv a commercial product on the.- marketand applicantplans to purchase this item.

watts.

and include it in the combination. Inoperation,

the heating element 28` acts more or` less4 as ai. switch means and ,doesnot allow electric'currentA to pass therethrough until it heatssuflicientlyf. taclose. contacslbyfexpansion of the contacts-.1' oll-.billlsfheid The .contacts loosesheat. after.:

being contacted once hence tend to` separate after a time interval `which `can easily be controlled by the size of resistors used. When elec., tric current passes. through the heating ele. ment 28, it owsto. contact points 2,9 and 30. that are spaced and mounted on a bar 3l. A pin member` 32 allows electric currentv to flow between contact points 29 and 30., when pin member 32 contacts the points 29 and 3|] as shown in Figure 2. Electric current. will then iiow to a solenoid 33., which will beenergized and pull bar :3l downwardly and thus open valve 26 to. allow pressure fluid to ilow from storage tank ii, conduitY 9; through valve 2.6; to valve structure Ill;

`It can thus be seen that the electrical actuai-` tion means 21 will operate soon after motor 5 starts into operation toV allow pressure fluid from storage tank 4 to` actuate valve structurer l0. The time interval between` the: starting of motor 5 and the opening of' valve 26 is. dependent on the size of; heating element 2 employed.

When bar 31. islpulled downwardly, pin. member 32. will" Contact magnetic coil'. 34' which is electricall-y.v connected with switch 1, and will thus be magnetizedi the whole. time switch 'l is closed and attract pin 32. When the contact points in heating element 28 are separated, electric current will no longer flow to solenoid 33` hence bar 3| is nollongerheldA by the solenoid 33 and the-spring (not shown) invalve 26; will force-valve 2t closed and. at the same time force bar 3l upwardly. Bar ti in moving upwardly will. not carry pin 32 up withit. since magnetic coil 34 isholding it. Th-iswil'l break electricalcontact between contactV points. 29 and 3D, hence electric current cannot again now throughlheating element 28 to solenoid 3'3; When switch l is opened again as storage tank 4; reaches its.` maximum pressure, electric current to magnetic coil 34 is closed oil, hence p in 321 is. no .longer helddownwardly by the magnet-ic coil. and a spring (not shown) mounted inbar. 3l moves pin 32'upwarolly again intocons tact with. contact points 29 and 3U. Thus the electrical actuationmeans is set to operate agairr when electric switch. 'l is closed and it can beseen that electrical actuation means will onlyV function once each timemotor 5-operates.

Whilefthe inventionzhas been described. in connection with speciiic embodiments, it is to beunderstoodthatcthe words: which have been used arewords ofdescription rather than-of limitation, andl that practice of: the inventionV within the` scope of. the appended claims may be resorted to-without departing from the true scope of thel invention in all its aspects I claim:

1. Incombination, a compressor unit including anfelectric motor-connectedthrough an unloader space toaI compressecrairstorage tank, an electrlcswitchconnected" to the compressor unit and actuated:v by the air pressure` in the storage tank, s-aid electric switch being` closed when the air' pressure-in the storage tank reaches a predetermined low. to .set the compressor -unit into operation andsaid electric `switch opened when the air said valvenormallyclosing Aoi flow.through'.th'e.s

conduit, said valve connected to the unloader space when the storage'tank reaches the predetermined high pressure and the compressor unit stops, said air under pressure in the unloader space flowing to the valve to exert its pressure to open the valve for a limited time interval each time the compressor unit operates and said air in the unloader space exhausting to the atmosphere through the valve.

2. In combination, a compressor unit including an electric motor connected through an unloader space to a compressed air storage tank, an electric switch connected to the compressor unit and actuated by the air pressure in the storage tank, said electric switch being closed when the air pressure in the storage tank reaches a predetermined low to set the compressor unit into operation and said electric switch opened when the air pressure in the storage tank reaches a predetermined high to stop operation of the compressor unit, said compressor discharging into the unloader space until the pressure existing in the storage tank is reached after which the unloader space opens to the storage tank, a Valve in a conduit connected to the bottom of the storage tank to drain any accumulated moisture from the storage tank through the valve to a disposed point, said valve normally closing oil the flow through the conduit, said valve connected to the unloader space when the storage tank reaches the predetermined high pressure and the compressor unit stops, said air under pressure in the unloader space flowing to the valve to exert its pressure to open the valve for a limited time interval each time the compressor unit operates, said air under pressure in the unloader space exhausting through a passage in the valve to the atmosphere and adjustable means in the passage to restrict the passage.

3. In combination, a compressor unit including an electric motor connected to a compressed air storage tank, an electric switch connected to the compressor unit and actuated by the air pressure in the storage tank, said electric switch being closed when the air pressure in the storage tank reaches a predetermined low to set the compressor unit into operation and said electric switch opened when the air pressure in the storage tank reaches a predetermined high to stop operation of the compressor unit, said compressor unit discharging into the storage tank until the predetermined high pressure is reached, a first valve a conduit connected to the bottom of the storage tank to drain any accumulated moisture from the storage tank through the first valve to a disposal point, said first valve normally closing off ilow through the conduit, a second conduit connecting the air under pressure from the storage tank t-o the first valve to exert its pressure to open the first valve, a second valve in said second conduit controlling iiow through the second conduit, an arm actuated by electrical means connected to. the switch and said arm pulled downwardly when the switch is closed to open the second valve for a limited time interval each time the compressor unit operates to allow air under pressure to flow from the storage tank to the iirst valve with said air exhausting from the first Valve to the atmosphere.

4. In combination, a compressor unit including an electric motor connected to a compressed air storage tank, an electric switch connected to the compressor unit and actuated by the air pressure in the storage tank, said electric switch being closed when the air pressure in the storage tank reaches a predetermined low to set the conipressor unit into operation and said electric switch opened when the air pressure in the storage tank reaches a. predetermined high to stop operation of the compressor unit, said compressor unit discharging into the storage tank until the predetermined high pressure is reached, a rst valve in a conduit connected to the bottom of the storage tank to drain any accumulated moisture from the storage tank through the first valve to a disposal point, said first Valve normally closing off now through the conduit, a second conduit connecting the air under pressure from the storage tank to the rst valve to exert its pressure to open the rst valve, a second valve in said second conduit controlling ow through the second conduit, an arm contacting the second valve to open the same, an electrical means connected to the switch through a heat control switch element, said electrical means operable to pull the arm downwardly when the heat control switch element is closed and the electric circuit to the electrical means broken when the arm moves upwardly so that the second valve is actuated once only each time the switch is closed.

5. In combination, a compressor unit including an electric motor connected to a compressed air storage tank, an electric switch connected to the compressor unit and actuated by the air pressure in the storage tank, said electric switch being closed when the air pressure in the storage tank reaches a predetermined low to set the compressor unit into operation and said electric switch opened when the air pressure in the storage tank reaches a predetermined high to stop operation of the compressor unit, said compressor unit discharging into the storage tank until the predetermined high pressure is reached, a rst Valve in a conduit connected to the bottom of the storage tank to drain any accumulated moisture from the storage tank through the rst valve to a disposal point, said rst valve normally closing oi ilow through the conduit, a second conduit connecting the air under pressure from the storage tank to the first Valve to exert its pressure to open the rst valve, a second valve in said second conduit controlling flow through the second conduit, an arm contacting the second valve to open the same, a solenoid electrically connected to the switch through a heat control switch element, said solenoid when energized operable to pull the arm downwardly to open the second valve when the heat control switch element is closed, an electro-magnet connected by a second circuit with the switch and energized when the switch is closed and a pin in the arm completing the circuit to the solenoid which pin contacts the electro-magnet and is held by the electroinagnet to break the circuit to the solenoid when the arm moves upwardly after the heat control switch element opens.

6. In a compressor unit and storage tank to compress and store air under pressure wherein the compressor unit maintains pressure in the storage tank at a predetermined high pressure the improvement comprising a Valve to connect into a storage tank to drain accumulated moisture from the storage tank intermittently with the valve having a housing, an inlet portion to be connected into the bottom of a storage tank,v

an outlet portion leading to a point of disposal, a passage in the valve housing connecting the inlet with the outlet, a valve seat associated with the passage in the housing with a valve member seating on the valve seat to close olfVV the passage, a portion of said valve member extending into a chamber within the valve housing with means in the chamber to keep the valve member seated, an inlet for a source of iiuid under pressure into the chamber to exert its pressure against the valve member to unseat the valve member and open the passage, an outlet passage from the chamber for the fluid under pressure and adjustable means in the outlet passage to restrict the size of the outlet passage.

7. In a compressor unit and storage tank to compress and store air under pressure wherein the compressor unit maintains pressure in the storage tank at a predetermined high pressure the improvement comprising a valve to connect into a storage tank to drain accumulated moisture from the storage tank intermittently with the valve having a housing, an inlet portion to be connected into the bottom of a storage tank, an outlet portion above the inlet portion leading to a point of disposal, a passage in the valve housing connecting the inlet with the outlet, a valve seat associated with the passage in the housing with a valve member seating on the valve seat to close off the passage, a portion of said valve member extending into a chamber within the valve housing with a spring in the chamber to keep the valve member seated, an inlet for a source of fluid under pressure into the chamber to exert its pressure against the valve member to unseat the valve member and open the passage, an outlet passage from the chamber to exhaust the fluid under pressure to the atmosphere and adjustable means in the outlet passage to restrict the size of the outlet passage.

8. In a compressor unit and storage tank to compress and store air under pressure wherein the compressor unit maintains pressure in the storage tank at a predetermined high pressure the improvement comprising a valve to connect into a storage tank to drain accumulated moisture from the storage tank intermittently with the valve having a housing, an inlet portion to be connected into the bottom of a storage tank, an outlet portion above the inlet portion leading to a point of disposal a passage in the valve housing connecting the inlet With the outlet, a valve seat associated with the passage in the housing, a valve member seating on the valve seat to close off the passage, said valve member attached to a piston movable within a chamber in the housing, spring means acting against the piston to hold the valve member in seated position on the valve seat against pressure from the storage tank, an inlet for e, source of fluid under pressure into the chamber to exert its pressure against the piston to unseat the valve member and open the passage and an outlet from the chamber to exhaust the duid under pressure to the atmosphere.

9. In a compressor unit including an electric motor and storage tank to compress and store air under pressure wherein the compressor unit maintains pressure in the storage tank at a predetermined high pressure the improvement comprising a valve to connect into a storage tank to drain accumulated moisture from the storage tank intermittently with the Valve having a housing, an inlet portion to be connected into the bottom of a storage tank, an outlet portion above the inlet portion leading to a point of disposal, a passage in the housing connecting the inlet with the outlet, a valve seat at one end of the passage, a valve member seated on the seat to close the passage, said valve member attached to a piston movable within a chamber in the housing, spring means with the chamber acting against the piston to hold the valve member in seated position on the valve seat against pressure from the storage tank, an inlet for a source of fluid under pressure into the chamber to exert its pressure against the piston to unseat the valve member and open the passage, an outlet passage from the chamber to exhaust fluid under pressure to the atmosphere and adjustable means in the outlet passage to restrict the size of the outletl passage.

l0. In a compressor unit including an electric motor and storage tank to compress and store air under pressure wherein the compressor unit maintains pressure in the storage tank at a predetermined high pressure the improvement comprising a valve to connect into a storage tank to drain accumulated moisture from the storage tank intermittently with the valve having a housing, an inlet portion to be connected into the bottom oi a storage tank, an outlet portion above the inlet portion leading to a point of disposal, a passage in the housing connecting the inlet with the outlet, a valve seat at one end or" the passage, a valve member seated on the seat to close the passage, said valve member attached to a rod extending through a seal into a chamber, said rod attached to a piston movable within the chamber, spring means within the chamber acting against the piston to hold the valve member in seated position on the valve seat against pressure from the storage tank, an inlet for a source of iiuid under pressure into the chamber to exert its pressure against the valve member through the piston to unseat the valve member and open the passage and an outlet from the chamber to exhaust iluid under pressure to the atmosphere.

11. In a compressor unit including an electric motor and storage tank to compress and store air under pressure wherein the compressor unit maintains pressure in the storage tank at a predetermined high pressure the improvement comprising a valve to connect into a storage tank to drain accumulated moisture from the storage tank intermittently with the valve having a housing,

an inlet portion to be connected into the bottom ol a storage tank, an outlet portion above the inlet portion leading to a point of disposal, a passage in the housing connecting the inlet with the outlet, a valve seat at one end of the passage, a valve member seated on the seat to close the passage, said valve member attached to a rod extending through a seal into a chamber, said rod attached to a piston movable Within the chamber, spring means within the chamber acting against the piston to hold the valve member in seated position on the valve seat against pressure from the storage tank, an inlet for a source of fluid under pressure into the chamber to exert its pressure against the valve member through the piston to unseat the valve member and open the passage and a controlled outlet from the chamber to regulate the time of discharge of nuid under pressure from the chamber to thus control the time interval the valve member is unseated.

RUSSELL C. CHURCHMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,128,206 Hewitt Aug. 23, 1938 2,255,565 Mantle Sept, 23, 1941 2,330,027 Churchman et al. Sept. 21, 1943

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