US1695978A - Damper for check valves - Google Patents

Description

Dec. 18,1928, 1,695,978

5. a. REDFIELD DAMPER FOR CHECK VALV ES Filed March 17. 1928 1 z e 1 g Y f1 w w k A I 3/ g I INVENTOR. E JnowdenBReQ'field BY Z HA3 ATTORNEY Patented Dec. 18, 1928.

- -ururrzn STATES PATIENT OFFICE. I

snownnn :B. REDFIELD, or EASTON, PENNSYLVANIA, nssrenoit T INGERSOLL-RAND' COMPANY, or JERSEY crrY, NEW JERSEY, A CORPORATION or NEWVJERSEY.

DAMPER FOR CHECK VALVES.

' Application filed March 17, 1928; Serial No'. 262,436.

check valve to remain constantly open 'dur ing the running period of the compressor.

Other objects will be in part obvious and in part pointed out hereinafter. The invention consists ofthe combinatio of elements and arrangement of parts hav 2 ing the general mode of operation substantiallyas hereinafter described and claimed and illustratedin the accompanying drawing, in which the figure is a longitudinal elevation of a portion of a compressor having 5 the invention applied thereto. I

Referring more particularly to the drawing, A designates a compressor cylinder havingan inlet connection B and a discharge opening C in its upper side to which is connected a discharge line D. Inlet and exhaust valves E and F respectively are indicated forcontrolling the admission of air into the cylinder and the exhaust of the compressed fluid from the: cylinder into the discharge line D. I a

Interposed in the discharge line D is an unloader G of the type described and illustrated in United StatesPatent No. 1,484,673

entitled Compressor unloader and granted 40 to Snowden B. Redfield, February 26.1924. The unloader G accordingly comprises a casing I-I divided into chambers J' and K by a wall L having a port 0 which terminates at the end adjacent the chamber J in a valve seat P. I

, In a hollow extension Q forming part of thecasing' His a relief valve R which con trols communication. between the chamber K and a. ventS in the extensionformain during the starting period of the compressor.

. ,As in the aforesaid patent the compressor cylinder A is provided at its ends with pilot valves T and U in which are disposed pistons V adapted to be actuated by pressure fluid entering the pilot valves T and U beneath said pistons V through openings W near the ends of the cylinder.

In the upper portions of the pilot valves '1 and U arepassages X having restricted portions Y to receive plunger-s or rods Z. The

upper and lower ends ofthe restricted porttions Y terminate in valve seats Z) and 0 respectively to accommodate ball valves 'e'and fwhi'ch are held in'spaced relation with respect to each other by means of the rods Z.

X are disposed sprmgsg exerting a constant pressure on the ball valves 6.

As may be ascertained by referring to the aforesaid patent, the function of the pilot valves l and U- is to relieve the pressure on the opposite sides of the compressor piston during the stopping and starting of the compressor and also to control the admission of pressure fluid into the hollow extension Q for maintaining the relief valve R closed during the time the compressor is loaded.

The pressure fluid utilized for actuating the relief valve R conveyed from the chain'- ber K of the casing H-through a pipe 7r connected to the top of the pilot valve T. Such pressure fluid may pass into the passage X and through the restricted portion Y of the pilot valve'T, thence through a port and through a pipe'lc connected at its op and K ofthe unloader in order to prevent the return of pressurefluid from the storage receiver 1 (not shown) into the compressor.

To this enda valve guide 0 is threaded into .the side of the casing H and has an extension 10 on which is slidably disposed a check valve 9 adapted to cooperate with the seat? for controlling the port 0. A spring 9 may be disposed on the check valve to return the check valve 9 to the seat P.

In accordance with the present invention, means are provided for preventing an ohjcctionable chattering or pounding of the check valve 9 particularly during the running of the compressor. Such chattering of the valve is caused by the pressure fluid discharged into the chamber K acting against the end of the valve and raising t oil the seat P and by the pressure fluid acting against the opposite side of the checkv valve 9 which again returns the valve to its during the suction stroke of the com- I passagew and in the absence of pressureon the valve 2 tending to maintain it in closed positiomsaid spring will raise the valve 2 to permit the flow of pressure fluid from the chamber J through said passages into the check valve 9 to maintain it on the seat P.

The actuation of the valve 2 is preferably effected automatically and at the time of starting and stopping oi. the compressor. In

order to induce such movement of the ball valve 2 a'cylinder 3 having an extension t which threaded into the recess y is pro vidcd with a piston 0 adapted to maintain the valve 2 closed pressure oi the piston 53 being transmitted to the valve 2 through the medium of a rod. (5 which extends through a hole? formed in the extension 4., said hole 7 preferably being of considerably greater cross sectional area than the rod 6. A vent V o in the cylinder affords communication between the hole 7 and the atmosphere.

The piston 5 is of the difl'erential type and accordingly has an enlarged head8 on the inner side of which is a tapered portion 9 adapted to cooperate with a correspondingly tapered seat 10 in the cylinder for preventing leakage of pressure fluid along the piston 5. A cover 11 on the cylinder 3 forms a closure therefor and has a chamber 12 into which pressure fluid may he admitted for actuating the piston 5.

In order to enable both the tapered portion 9 of the piston 5 and the valve 2 to be tightly pressed to theirrespective-seats a plunger 13 is disposed in the piston 5 'With respect to which it is capable'ot limited longitudinal movement. A spring 14. is disposed in the piston to act against the plunger tor the purpose of forcing said plunger in the direction of the ball valve 2. Preferably a pin 15 seated with its ends in the piston '5 extends through a transverse slot 16 in the plunger to limit such movement of the plunger in the piston. V t by The pressure fluid utilized for actuating the piston 5 is in this instance conveyed to the chamber 12 by a pipe 17 which is. connected at one end to the cover 11 and at its other end to the pipe leading to the hollow extension Q of the unloader.

The operation of the device is as follows: During the time when the compressor is operating under normal conditions, that-is,

. when itis operating at the maximum speed,

a portion of the pressure fluid discharged. from the cylinder Ainto the chamber K will flow through thep pe h, the pilotvalve T and the pipe 7c into the pilot valve U, thence through the pipe into the hollow extension Q, for maintaining the relief valve R closed against the pressure in the cha1nber K. v

Inasmuch as the cylinder 3 is connected to the pipe is by means of the pipe 17 pressure fluid, will therefore also flow through the said pipe 17 into the chamber 12 and, acting against the piston 5, will press said piston against the tapered seat 10. Such movementof the piston 5 will be transmitted to the ball valve 2 by ineansof the rod'6 and the ball valve 2 will be held in closed position to prevent the admission of pressure fluid from the chamber J into the check valve 9. The check valve q theretorefree to move outwardly on the extension 0 of the valve guide for opening the port 0.

'Due to the rapid reeiprocations of the compressor piston while operating at maxinuun speed suflicient pressure will be main tained beneath the pistons V of the pilot valves to hold said pistons in their uppermost positions.- Inasmuch as the movement of the valves 0 and f is directly dependent upon the movement of the pistons theball valves 0 and f will also be maintained in their uppermost positions, that is the valves f will bear against their seats 0 and the valves 0 will be raised from the'seats Z); In these positions of the valves 0 and 7 there is a direct'anu uninterrupted communication between the source of pressure fluid supply and the chamber 1201 the cylinder3, as well a as with the hollow extension Q of the un-v loader. I I p p During the stopping of the compressor the speed Jot the] compressor piston gradually decreases the average pressure he neath the pistons .V of the pilot valvesT and i U also decreases. o-lVh'en such pressure fluid" reaches a certain 'valuethe pistons V will reciprocate in the pilotvalves in step with the stroke of the compressor piston. .This movement of the pistons V will of course 'result in a corresponding movement of the ball valves 6 and 7 so that on each suction stroke of the compressor piston one ball valve 6 will return to its seat while the,

. the relief valve Rand the ball valve 2 closed to escaoe to the atmos here throu h the pipes connecting these elements with the pilot valves.

After sufficient pressure fluidhas been exhausted from the chamber 12 to enable,

the spring 2 and'the pressure fluidacting against the valve 2 to retract the-piston and raise the ball valve, zpressure fluid will flow through the passage 00 into the recess 4 thence through the'passage w into the check valve and hold the check valve g closed. I

The check valve'q will be heldfclosedby eration' and remains closed until the com.-

pressurefluid during the stopping and-idle periods as well as during the starting period of the compressor. After the compressor is again set in operation a portion of the fluid compressed in the ends of the. cylinder A will again be exhausted into the pilot valves T and U.

YVhile the compressor. piston is recipro-d eating slowly, the pressure fluid] acting aga nstthe pistons V of the p lot valveswill cause reciprocation of said pistons in step with the compressor piston'so that on each compression'stroke thevalves e and f will be raised and lowered. I v y Until the reciprocationsofthe compressor .)iston take place'in such rapid succession that asufliciently high average pressure may be maintained beneath the pistons V said pistons will of course reciprocate as will also the ball valves 6 and During this period pressure fluid wlll bGIhSCl'ltllgfll -1nto the chamber K and a portion thereof will flow through the pipe 'ib into the pilot valves T and Udue to the-throttling action of the relief valve B. Owing to the 'ecipi'OCatOry movement of the'ball valves e and 7 however such pressure fluid Wlll be exhausted valves T and U. I

lVhen the movement of the compressor directly tothe atmosphere from the pilot.

piston is accelerated the pressure beneath the pistons V will become ofsufficient value to maintain the pistons V in their uppermost position and thus also to maintain the valves f against the seats-0 and the valves 6 unseated. When the valvese and f occupy these positions pressure fluid may flow from cylinderanda discharge line; a valve casing interposed in the discharge line, a valve guide inthe casing, a check valve. on,v the:

the chamber K through the elements con meeting. said chamber with the hollow extenmaintain the relief valve R closed and will 7 also depress the pi'ston5.

checkvalve 9 ,may' escapethrough the passage w and the hole 7 intothe front end of the cylinder' fromi whence it may escape to the atmosphere through the vent 0.

After theball valve .2 is closed the interior of the. check valve will be subjected only to J atmospheric pressure so that said check valve may bereadily opened and maintained in an open position by the pressure fluid existingin the chambers J and K, unaifected by any. back flow of pressure fluid through the port 0. By'enabling the checkv valve 9 to con-' stantly, remain open during ,the normal operation. of the compressor the objectionable noisehereinbefore referred to will be en,- tirely eliminated as the check valve contacts with its'seat only after each period of oppressor again approaches its normal speed.

I claim: v 1. vIn a compressor, the combination of a cylinder and a discharge line, check valve controlling communication between the cylinder and the dischargeline, and pressure actuated means to maintain the check valve closed during the accelerating, stopping and idle periods ofthe compressor and to enable said check valve to remain constantly open during thejrunning period of the compressor. i

2. In a compressor, the combination ofa cylinder and a discharge line, a check valve controlling communication between the cyl-r inder and the discharge line, and pressure actuated means for controlling the admission of pressure fluid into the'check valve to maintain said checkvalve closed during the accelerating ,stopping and. idle periods of the compressor and to enable said checkvalve to remain constantly open duringthe running period of the compressor.

} 3. In a compressor, the combination of a cylinder and a discharge line a check valve This movement.

controlling communication between the cylinder and the discharge line, and pressure actuated. means for controlling the admission of. pressure fluid from the discharge line into the check valve to maintain said check valve closed during the accelerating, stopping and idle periods of ,thecompressorand to enable said. check valve to remain constantly open during the running period of the compressor. 7

4. In acompressor, the combination ofa guide to control the flow of pressure fluid through the discharge line, and pressure actuated means supported by the valve guide and adapted to admit pressure fluid from the discharge line into the check valve to maintain said check valve closed during the starting, stopping and idle periods of the compressor and to enable said check valve to remain constantly open during the running period of the compressor.

5. In a compressor, the combination of a cylinder and a discharge line, an unloader for the compressor connected to be actuated by pressure fluid from the cylinder, a check valve controlling the flow of pressure fluid through the discharge line, and. pressure actuated means communicable with the unloader for controlling the admission of pressure fluid into thecheck valve to hold said valve closedduring the starting, stopping and idle periods of the compressor and to enable said check valve to remain constantly open during the running period of the compressor.

G. In a compressor, the combination of a cylinderand a discharge line, an unloader for the compressorconnected to be actuated by pressure fluid from the cylinder, a check valve controlling the flow of pressure fluid throi'lgh the discharge line, and pressure actuated means communicable with the unloader for controlling the admission of pressure fluid from the discharge line into the check valve to maintain said check valve closed during the starting, stopping and idle periods of the compressor and to enable said check valve to remain constantly open during the running period of the compressor.

7. In a compressor, the combination of a cylinder and a discharge line, a valve casing interposed in the discharge line, a valve guide in the casing having a pair of passages, a check valve slidable on the guide to control the flow of pressure fluid through. the discharge line, and pressure actuated means supported by the valve guide for controlling the flow of pressure fluid from the discharge line through the passages into the check valve to hold SflKl (JllGClCVEllVG closed during the starting, stopping and idle periods of the compressor and to en-J line into'the check valve to maintain thecheck valve closed during the starting, stop ping and idle periods of the compressor and to enable said check'valve to remain constantly open during the running period ot the compressor.

9. In a compressor, the combinationot a cylinder and a discharge llne, a valve casing interposed in the discharge line, a valveguide in the casing having a pair of passages, a check valve on'the guide to control pressure fluid from the discharge line intothe check valve for maintaining the check valve closed during the starting, stopping and idle periods of the, compressor, and a pipe for conveying pressure fluid into the last said cylinder to actuate the piston and hold the valve closed during the normal operation of the compressor. i

10. In a compressor, the combination of a cylinder and a discharge line, a valve casing interposed in the discharge line, a valve guide in the casing having athreaded recess and a pair of passages communicating With the recess, a cylinder having a stem threaded into the recess, a hole in the stem, said cylinder having a vent, a piston in the cylinder, a valve in the recess controlling communication between the passages, a rod in the hole for transmitting the movement of the piston to the valve, a spring to open the valve to admit pressure fluid from thedischarge .line into the check valve for holding said check valve closed during the start ing, stopping and idle periods of the compressor, and a pipe for conveying pressure fluid into the last said cylinder to actuate the piston-and close the valve during the normal operation 01' the compressor,thus permitting the pressure fluid in the check valve to escape through the said hole and the vent to the atmosphere and permitthe' check valve to open during the running pe riod ot the compressor.

11. In a compressor, the combination of a cylinder and a discharge line, a valve casing interposed in the discharge line, a valve guide in the casing having apair of passages, a check valve on'the valve guide to control the flow ofpressure fluid through the discharge line, a valve in the valve guide to control communicationbetween the pas-- sages, a cylinder supported by the valveguide, a piston in. the cylinderconnected to actuate the valve, a spring'for opening the valve, and pilot valves on thefirst said cylinder for relievlng the pressure in the ends of the cylinder on stopping of the comprcs-' Cil sor, said pilot valves being connected in series With each other and with the'casing and the second said cylinder to admit .pressure fluid to the cylinder to act against the piston for maintaining the valve closed during the normal operation of the compressor and-for exhausting such pressure fluid from the cylinder, thereby enablin rthe spring .to open the valve for admitting pressure fluid into the check valve and hold said 10 check valve closed during the starting, stopping and idle periods of the compressor.

SNOWDEN B. REDFIELD.

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