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Publication numberUS3341111 A
Publication typeGrant
Publication dateSep 12, 1967
Filing dateApr 27, 1965
Priority dateApr 27, 1965
Publication numberUS 3341111 A, US 3341111A, US-A-3341111, US3341111 A, US3341111A
InventorsSanders Walter J
Original AssigneeWestinghouse Air Brake Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Automatically controlled drain valve
US 3341111 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

p 12, 1967 w. J. SANDER-S 3,341,111

AUTOMATICALLY CONTROLLED DRAIN VALVE Filed April 27, 1965 INVENTOR. WALTER J. SANDERS mm /W ATTORNEY United States Patent Ofiice 3,341,111 AUTOMATECALLY CONTROLLED DRAW VALVE Walter J. Sanders, Jeannette, Pa., assignor house Air Brake Company, Wilmerding, ration of Pennsylvania Filed Apr. 27, 1965, Ser. No. 451,223 7 Claims. (Cl. 2301) to Westing- Pa., 21 corpo- ABSTRACT OF THE DISQLOSURE Various arrangements known in the art have been devised for periodically and automatically removing moisture accumulated by condensation in a compressed air storage reservoir of an air compressing system, such arrangements usually including a drain valve fixed to the storage reservoir adjacent a sump or drainage chamber in which the condensate accumulates. In some of the presently used automatic drainage arrangements, the drain valve is of the self-closing'type operable responsively to air pressure to open an atmospheric communication and thereby allow the condensate to be forced out by air pressure in the storage reservoir to which the drainage chamber is annexed, the drain valve t-hen closing automatically after a predetermined period of time. In such arrangements, the air pressure for actuating the drain valve to open the atmospheric communication is usually the air pressure supplied via a compressor governor to the compressor unloader for unloading the compressor when pressure in the storage reservoir has attained a predeter-' mined maximum, and drainage of the condensate, therefore, occurs at the beginning of the period during which the compressor operates in the unloaded condition.

An arrangement is also known whereby the drainage apparatus operates automatically to effect drainage of condensate at the end of the unloaded period of the compressor, for, as is *well known, moisture vapor present in compressed air condenses due to cooling of such compressed air, and since a greater amount of cooling in the storage reservoir occurs during the period that the compressor operates unloaded, it follows that a greater amount of moisture condensation occurs during such unloaded period. It is more desirable, therefore, to have drainage of condensate occur at the end of the unloaded period because removal of a maximum amount of condensate from the compressed air stored for usage is thereby effected, allowing a minimum of objectionable and possibly damaging moisture to reach the device or devices to which the compressed air is supplied.

Also characteristic of the operation of some of the presently known air compressing systems is that, follow- I ing operation of the compressor governor to cause release Patented Sept. 12, 1967 of air pressure from the compressor unloader device for loading the compressor when pressure in the reservoir has reduced to a predetermined minimum, such air pressure from the compressor .unloader is usually released directly to atmosphere.

The object of this invention, therefore, is to provide apparatus including a drain valve device controlled in a novel manner so as to automatically effect drainage of condensate from a drainage chamber associated with an air pressure storage reservoir of an air compressing system at the end of the unloaded period of the compressor, or in other words, at the onset of the loaded period of operation of the compressor, said drain valve device being actuated by air pressure released from the compressor unloader when effected by the compressor governor for commencing loaded operation of the compressor.

The invention herein disclosed comprises a novel arrangement of a drain valve device in an air compressing system including a storage reservoir supplied with compressed air from an air compressor the operation of which is controlled, in well-known manner, by a governor device operable responsively to a predetermined high pressure in the storage reservoir for effecting supply of actuating air at said high pressure to a compressor unloader device for unloading the compressor and to a predetermined low pressure in the storage reservoir for causing said actuating air to be exhausted from said unloader device for loading the compressor, said drain valve device being connected via a pipe to the exhaust or vent port of the governor device via which said actuating air is exhausted from the unloader device, whereby said drain valve device is actuated by such air pressure exhausted from the unloader device to effect drainage of condensate from the storage reservoir at the end of the unloaded period of the compressor. An atmospheric choke is provided between the exhaust port in the governor device and the drain valve device in the pipe connecting them, the size of said choke being such as to provide adequate relief of air pressure from the unloader device for eifecting prompt restoration of the compressor to its loaded condition while at the same time providing the necessary restriction for delaying dissipation of such air pressure sufliciently for insuring positive operation of the drain valve to an open position. Air pressure in the connecting pipe and the drain valve is eventually dissipated to atmosphere via said choke to thereby condition the drain valve for subsequent op eration, the flow rate of said choke, determining the length of time that the drain valve is open for draining condensate during each cycle of operation.

In the drawing, FIG. 1 shows a schematic arrangement of an air compressing system embodying the invention including an automatic drain valve device shown in section, and FIG. 2 shows a portion, in section, of the drain valve device somewhat modified.

As shown in the drawing, an air compressing system embodying the invention may comprise an air compressor 1, a storage reservoir 2 (only a portion being shown) to which compressed air from the compressor is supplied via a conduit 3, a check valve device 4 interposed in said conduit for preventing back flow therethrough, a compressor governor device 5 for controlling a plurality of compressor unloader devices 6 associated respectively with each cylinder of the compressor, the inlet side of said compressor governor device being connected to said storage reservoir and conduit 3 via a conduit 7 and the delivery side being connected to said compressor unloaders via a conduit 8, and a drain valve device 9 affixed to said storage reservoir and connected via a conduit 10 to an exhaust or vent port 11 of the compressor governor device.

The drain valve device 9 comprises a casing 12 afiixed by suitable means (not shown) to the bottom of the storage reservoir 2. A piston assembly 13 operably disposed in casing 12 comprises a diaphragm type piston 14 which cooperates with said casing to define therein and on opposite sides of said piston a high-pressure chamber 15, connected directly to conduit 10 via a passageway 16, and a low-pressure chamber 17 connected to conduit 10 via a choke element 18 supported in said casing, said choke element thereby providing restrictive communication between said passageway and said low-pressure chamber.

The casing 12 is also provided with a drainage chamber 19 which is in direct communication with the storage reservoir 2 via a passage 20 formed in said reservoir. A normally seated ball valve 21, for example, is disposed in the drainage chamber 19 for controlling communication between said drainage chamber and atmosphere. The ball valve 21 is adapted, when in a closed position, that is, seated on an annular valve seat 22 surrounding an atmospheric port 23 formed in casing 12, to cut off communication between drainage chamber 19 and atmosphere, said ball valve being operable to an open position unseated from said valve seat whereby condensate accumulated in said drainage chamber from reservoir 2 may be drained from said drainage chamber to atmosphere via said atmospheric port in a manner to be hereinafter described.

The piston assemblage 13 further comprises a piston stem 24 extending coaxially from the side of piston 14 adjacent low-pressure chamber 17 with the free end of said piston stem extending through casing 12 and terminating externally thereof to bear on one end, which may be called the piston stem end, of a valve-operating arm or lever 25. The valve-operating arm or lever 25 is pivotally supported between its two ends by a pin 26 on the exterior of casing 12 and has formed, on what may be called the valve end of said arm opposite the piston stem end, a finger 27 extending through atmospheric port 23 to make abutting engagement with the portion of ball valve 21 encircled by valve seat 22. A spring 28 encircling piston stem 24 in low-pressure chamber 17 urges the piston assemblage 13 upwardly, as viewed in the drawing, toward a valve-closing position in which pressure exerted by the free end of piston stem 24 on the piston stem end of valve-operating arm 25 is relieved therefrom. Consequently, due to the pivotal action of arm 25, air pressure acting on the side of ball valve 21 adjacent drainage chamber 19 and through said ball valve causes pivotal movement of arm 25 in a counterclockwise direction, as viewed in the drawing, to a normal rotated position in which said air pressure is effective for maintaining said ball valve in its closed position, above described, and thereby cut off communication between said drainage chamber 19 and atmospheric port 23.

An atmospheric choke device 29 of predetermined flow capacity is interposed in conduit 10 adjacent the exhaust port 11 of the governor device 5 to provide restricted venting of air pressure from said pipe to atmosphere for a purpose to be hereinafter disclosed.

In considering and understanding the operation of the improved automatic drain valve apparatus embodying the invention, a brief description regarding the operation of the well-known devices associated therewith will be considered. As is well known to those skilled in the art, the governor device 5 functions to control operation of the air compressor 1 through the compressor unloadcr devices 6 to maintain pressure in the storage reservoir 2 within a predetermined operating range between minimum and maximum pressure values or settings. That is, when pressure in the storage reservoir 2 has attained the maximum pressure setting due to compressing operation of the compressor 1, the governor device 5 operates responsively to such maximum pressure to open communication between conduits 7 and 8 to allow air at said maximum pressure to flow to the compressor unloader devices 6 which are actuated responsively to such air pressure to unload the compressor, as, for example, by holding the intake valve of the corresponding cylinder open, thus preventing further compression of air by the compressor and consequent further buildup of pressure in the storage reservoir and at the same time, if desired, through conventional control means (not shown) cause the compressor driving motor (not shown) to run at idling speed or stop. Upon reduction of pressure in the storage reservoir 2 to the minimum pressure setting, such as through use of compressed air stored in the reservoir, the governor device 5 operates to close communication between conduits 7 and 8 to thereby cut off flow of pressurized air to and effect exhaust of actuating pressure from the compressor unloader devices 6 which, in turn, operate to load the compressor 1, as by allowing the intake valve of each cylinder to operate normally, and restoring the speed of the compressor driving motor to a normal operating rate, for compressing air and recharging the storage reservoir with pressurized air until the maximum setting is reached once more.

When the governor device 5 operates responsively to the minimum pressure setting for cutting off communication between conduits 7 and 8 for restoring the air compressor 1 to a loaded condition, as above noted, actuating air pressure exhausted from the unloader devices 6 flows therefrom via conduit 8, the exhaust port 11 in said governor device and conduit 10 to high-pressure chamber 15 via passageway 16 of the drain valve device 9 and to low-pressure chamber 17 via the choke 18. Due to restriction of flow of pressurized air to low-pressure chamber 17 imposed by choke 18, such pressurized air supplied concurrently and unrestrictedly to high-pressure chamber 15 is momentarily effective for establishing a pressure differential between the opposite sides of piston 14 and thereby exert on said piston an impulse sufiicient for overcoming the opposing force of spring 28 so as to cause piston assemblage 13 to be moved downwardly, as viewed in the drawing, to a valve-opening position. Downward movement of piston stem 24 causes sufficient clockwise pivotal movement of arm 25, as viewed in the drawing, to a rotated position in which ball valve 21 is unseated by finger 27. With ball valve 21 unseated, condensate accumulated in drainage chamber 19 is discharged to atmosphere via port 23 by the force of air pressure from storage reservoir 2 via passage 20 blowing past the unseated ball valve.

The ball valve 21 is held in its unseated or open position until the pressure in high-pressure chamber I15 is sufficiently reduced or dissipated through choke 29 to render spring 28 effective for restoring piston assemblage 13 to its valve-closing position, the time interval during which said ball valve is held in its said open position being determined mainly by the preselected flow capacity of said choke 29. The choke 18 interposed between passageway 16 and low-pressure chamber 17 merely serves as a tuning choke via which a fixed amount of air pressure, as determined by the size of said choke, is permitted to flow to low-pressure chamber 17 at the same time it is supplied to high-pressure chamber 15, thereby partially equalizing the pressure in high-pressure chamber 15 above piston 14 and thus, in effect, assisting spring 28 in resisting downward movement of piston assemblage 13 and then in restoring the piston assemblage to its valve-closing position. If, therefore, low-pressure chamber 17 were completely cut off from pressure in passageway 16 and opened directly to atmosphere, in a manner to be hereinafter described, the time interval during which ball valve 21 remains open would be determined solely by the size of choke 29. This time interval can be reduced, however, by closing low-pressure chamber 17 to atmosphere and by providing the tuning choke 18, as above described, the amount of such reduction in the time interval being variable according to the size of the orifice in said tuning choke, that is, the larger said orifice is, the greater the reduction of the time interval.

The dimension or flow rate of choke 29 is more critical than that of choke 18. Since it is not considered necessary to the understanding of the invention, the structural details of the governor device 5 are not shown in the drawing. The governor device 5, however, does include a valve element which is retained in one position by pressure in the reservoir 2 as long as such reservoir pressure exceeds the minimum value. In the one position of the valve element, communication between conduits 7 and 8 is open for maintaining reservoir pressure in the unloader device 6 whereby the compressor 1 is maintained in an unloaded condition of operation until said reservoir pressure is reduced to the minimum value. Upon reduction of reservoir pressure to the minimum value, however, operation of the valve element in the governor device 5 to a different position is initiated to open communication of conduit 8 to exhaust port 11 and thereby to atmospheric choke 29 to permit actuating pressure in the unloader devices 6 and that acting on the valve element in thegovernor device to be exhausted to atmosphere via said choke. The flow rate of choke 29 must be and is such that exhaustion of air pressure from the unloader devices 6 and that acting on the valve element of the governor device 5 occurs at a sufficiently rapid rate as to effect immediate loaded operation of the compressor 1 and snap action of said valve element to its different position. It is desirable, therefore, to locate the choke 29 in the proximity of the exhaust port 11 to assure prompt relief of pressure as above described. On the other hand, the flow rate of choke 29 must also be sufficiently restrictive for causing sufficient air pressure eX- hausted from the unloader devices 6 to reach and attain effectiveness in high-pressure chamber 15 for operating piston assemblage \13 to its valve-operating position, as above described.

All air pressure in conduit and in both chambers 15 and 17 of the drain valve device 9 is eventually dissipated, that is, after a period of time determined jointly by the respective flow capacities of atmospheric choke 29 and tuning choke 18, when said tuning choke is provided and as above described, so that said drain valve device, in its normal closed condition, will be void of any air pressure and thus in condition for the succeeding drainage cycle, which will be effected at the conclusion of the next unloaded period of the compressor.

If the tuning choke 18 is not desired for purposes of modifying the time interval provided by atmospheric choke 29, as above explained, the drain valve device 9 may be modified by simply substituting a plug 30 for the tuning choke 18 and removing a plug 31 provided in a port 32 in casing 12. By .such modification, lowpressure chamber 17 is closed to prevailing pressure in passageway 16 and opened to atmosphere via port 32 in casing -12, as shown in FIG. 2 of the drawing. It should be apparent with such an arrangement, that is, without diversion of any air pressure to low-pressure chamber 17 and partial equalization of pressure in high-pressure chamber 15, the time interval for dissipating the pressure in said high-pressure chamber and conduit 10 is determined solely by the flow capacity of atmospheric choke 29.

As will be observed, the valve-operating arm 25 of the drain valve device 9 is arranged exteriorly of casing 12 in such manner that if so desired and deemed necessary, the automatic drain valve device 9 may be operated manually, at any time, independently of automatic operation thereof, simply by applying manual effort to said arm to effect clockwise pivotal movement thereof to un- 6 seat the ball valve 21. When the arm 25 is released, air pressure in drainage chamber 19 is effective for reseating ball valve 21 on seat 22.

Having now described the invention, what I claim as new and desire to secure by Letters Patent is:

1. For use in a compressed air system wherein a compressor supplying compressed air to a storage reservoir is loaded and unloaded responsively to variations of pressure in the reservoir, an automatic drain valve apparatus comprising, in combination:

(a) a valve having a normally closed position and be ing operable to an open position for draining condensed moisture from the reservoir,

(b) valve-operating means actua'ble responsively to air under pressure for operating said valve to its said open position,

(c) control means operable responsively to air in the reservoir at a certain high value for effecting supply of air under pressure for causing the compressor to be unloaded and being operable responsively to air in the reservoir at a certain lower value for effecting venting of air under pressure for causing the compressor to be loaded and supplying such vented air under pressure to said valve-operating means for causing said valve to be operated to its said open position,-and

(d) atmospheric choke means via which such vented air under pressure supplied to said valve-operating means is dissipated.

2. In a compressed air system, in combination:

(a) a reservoir for storing compressed air,

(b) a compressor including an unloader device operable responsively to air under pressure for unloading the compressor and to release of such air under pressure for loading the compressor,

(0) a governor device operable responsively to air in said reservoir at a certain high pressure for effecting supply of air under pressure to said unloader device and operable responsively to air in said reservoir at a certain lower pressure for effecting release of air under pressure from said unloader device,

(d) a drain valve device including a valve member having a closed position and being operable to an open position for draining condensed moisture from the reservoir,

(e) valve-operating means operable responsively to said air pressure released from said unloader device by said governor device for causing operation of the valve member to its said open position, and

(f) atmospheric choke means via which said air pressure released from the unloader device and supplied to the valve-operating means is dissipated after a preselected time interval, as determined by the flow capacity of said choke means, for effecting restoration of said valve member to its said closed position.

3. For use in a compressed air system wherein a compressor supplying compressed air to .a storage reservoir is loaded and unloaded responsively to variations of pressure in the reservoir, an automatic drain valve apparatus comprising, in combination:

(a) a valve having a normally closed position and being operable to an open position for draining condensed moisture from the reservoir,

(b) a pivotally supported lever having one end engageable with said valve and being pivotally operable out of a normal position, in which said valve is in its closed position, to a different position in which said valve is operated to its said open position,

(c) piston means operatively engaging the opposite end of said lever and being subjectable to opposing air pressure supplied to respective chambers adjacent opposite sides of said piston means,

((1) control means operable responsively to air in the reservoir at a certain high value for effecting supply of fluid under pressure for causing the compressor to be unloaded and being operable responsively to air in the reservoir at a certain lower value for effecting venting of air under pressure for causing the compressor to be loaded and supplying such vented air under pressure to said chambers, and

(e) choke means intercommunicating said chambers with each other and effective for causing a pressure differential across opposite sides of said piston means upon supply of said air under pressure to said cham bers by said control means,

(f) said piston means being axially movable in one direction to a valve-opening position responsively to said pressure differential for effecting pivotal movement of said lever to its said different position.

4. An air compressing system comprising, in combination:

(a) acompressor,

(b) a reservoir for receiving compressed air from the compressor,

(c) an unloader device operable responsively to air under pressure for unloading said compressor and to venting of such air under pressure therefrom for loading said compressor,

(d) a governor device operable responsively to air pressure in the reservoir at a certain maximum value for effecting supply of air under pressure to the unloader device and responsively to air pressure in the reservoir at a certain minimum value for causing such air under pressure to be vented from the unloader device via a vent port in said governor device,

(e) an automatic drain valve comprising:

(i) acasing,

(ii) a valve member operably disposed in said casing and subject to and biased by air pressure in the reservoir toward a closed position, said valve being operable to an open position for draining condensed moisture from the reservoir,

(iii) a lever pivotally supported on said casing with one end operatively contacting said valve member and therefore subject to the biasing effect of reservoir pressure acting on the valve member so as to be pivotally biased in one direction toward a normal position in which said valve member is in its closed position, said lever being operable upon pivotal movement thereof in a direction opposite to said one direction to a rotated position for operating said valve memher to its said open position,

(iv) piston means subject in opposing relation to air pressure in chambers formed by said casing and said piston means on opposite sides of the piston means,

(v) choke means intercommunicating said chambers with each other and effective for causing a pressure differential across the opposite sides of said piston means upon supply of air under pressure to said chambers,

(vi) a piston stem extending from one side of said piston means with its free end operatively contacting the other end of said lever opposite its said one end,

(vii) said piston means and said piston stem being operable responsively to said pressure differential to valve-opening positions in which a force sufficient for overcoming the biasing effect of pressure in the reservoir is exerted on and transmitted through said lever for operating it to and retaining it in its said rotated position until air pressure in said chambers is equalized via said choke means,

(viii) biasing means in one of said chambers effective upon equalization of air pressures in said chambers for urging said piston means and said piston stem to valve-closing positions in which said lever is relieved of said force and said biasing effect of air pressure in the reservoir acting on and through said valve member is rendered effective for causing pivotal movement of said lever in said one direction to its said normal position and therefore restoration of said valve member to its said closed position,

(f) conduit means via which air under pressure vented by the governor device from the unloader device flows from the vent port in said governor device to said chambers of said automatic drain valve for establishing said pressure differential across the opposite sides of said piston means, and

(g) an atmospheric vent choke interposed in said conduit means and via which such air under pressure supplied to said chambers is dissipated to atmosphere subsequently to expiration of a predetermined time interval.

5. Automatic drain valve apparatus, as defined in claim 3, wherein said piston means further comprises:

(a) a piston stem extending from one side of said piston means with its free end operatively contacting the other end of said lever for effecting said pivotal movement thereof to its said different position upon axial movement of said piston means in its said one direction, and

(b) biasing means effective upon release of air pressure acting on said piston means for causing axial movement of said piston means in a direction opposite to said one direction to a valve-closing position in which said lever is operated to its said normal position for restoring said valve to its said closed position.

6. Automatic drain valve apparatus, as defined in claim 5, further characterized by atmospheric choke means via which air pressure supplied to said chambers and acting on said piston means for effecting operation thereof to its said valve-opening position is released after a preselected time interval, as determined by the flow capacity of said choke means, for rendering said biasing means effective for operating said piston means to its said valve-closing position.

7. An air compressing system comprising, in combination:

(a) acompressor,

(b) a reservoir for receiving compressed air from the compressor,

(c) an unloader device operable responsively to air under pressure for unloading said compressor and to venting of such air under pressure therefrom for loading said compressor,

(d) a governor device operable responsively to air pressure in the reservoir at a certain maximum value for effecting supply of air under pressure to the unloader device and responsively to air pressure in the reservoir at a certain minimum value for causing such air under pressure to be vented from the unloader device via a vent port in said governor device,

(e) an automatic drain valve comprising:

(i) a valve member having a normally closed position and being operable to an open position for draining condensed moisture from the reservoir,

(ii) piston means operatively engaging said valve member and being operable out of a normal position responsively to actuating air pressure to a valve-operating position for effecting operation of said valve member to its said open position, and

(iii) biasing means effective upon releas of such actuating air pressure acting on said piston means for restoring said piston means to its said normal position,

(f) conduit means via, which air. under pressure vented 8,341,111 9 10 by said governor device from said unloader device References Cited flows from said vent port in the governor device to UNITED STATES PATENTS said automatic drain valve for actuating said piston means to its said valve-operating position, and g 25 (g) atmospheric choke means interposed in said con- 5 3004549 10/1961 T man 23 duit means and via which said actuating air pressure emp e 1S .dlsslpated from i at a Predetfir' DONLEY J. STOCKING, Primary Examiner. mined rate for rendering said biasing means effectlve to restore said piston means to its said normal posi- LAURENCE EFNER, Examinertion after a perdetermined time interval, 10 L KRAUSS Assistant Examiner

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2345380 *Jul 30, 1942Mar 28, 1944Westinghouse Air Brake CoDrain valve mechanism
US2571420 *Jul 12, 1947Oct 16, 1951Nellie ChurchmanMechanism for draining moisture from compressed-air storage tanks
US3004549 *Oct 29, 1959Oct 17, 1961Westinghouse Air Brake CoCombined automatic and manual drain valve
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US8596292Aug 22, 2011Dec 3, 2013Dresser-Rand CompanyFlush-enabled controlled flow drain
US8657935May 19, 2011Feb 25, 2014Dresser-Rand CompanyCombination of expansion and cooling to enhance separation
US8663483Jun 28, 2011Mar 4, 2014Dresser-Rand CompanyRadial vane pack for rotary separators
US8673159Jun 28, 2011Mar 18, 2014Dresser-Rand CompanyEnhanced in-line rotary separator
US8821362Jun 28, 2011Sep 2, 2014Dresser-Rand CompanyMultiple modular in-line rotary separator bundle
US9095856Feb 3, 2011Aug 4, 2015Dresser-Rand CompanySeparator fluid collector and method
US20060222515 *Mar 29, 2006Oct 5, 2006Dresser-Rand CompanyDrainage system for compressor separators
US20070264135 *May 15, 2006Nov 15, 2007Michael HartlDrain Valve Assembly for Use in an Air Compressor System
WO2006054075A1 *Nov 16, 2005May 26, 2006Mb Air Systems LimitedImproved air receiver and associated apparatus
WO2007133946A2 *May 2, 2007Nov 22, 2007New York Air Brake CorporationDrain valve assembly for use in an air compressor system
WO2007133946A3 *May 2, 2007May 15, 2008New York Air Brake CorpDrain valve assembly for use in an air compressor system
Classifications
U.S. Classification137/115.24, 137/204
International ClassificationF04B39/16
Cooperative ClassificationF04B39/16
European ClassificationF04B39/16