US3379211A - Compression control valve - Google Patents

Description

April 23, 1968 R. J. MORSE COMPRESSOR CONTROL VALVE Filed Nov. 5, 1965 5 RE m 0% n m m W 2 O 8 N f 46 -F 6 4 6 I A 3 m 1 a 4 6 E 4 5 3 w 4 fI R 8 v 5 7- l J m7 M x i O 5 V 2 2 Y I 06 m 2 B R W. 5 4 h 6 T m 8 V 7 2 m a S I E R, I O 4 T FROM PRESSURE sou United States Patent Ofi ice 3,3 79,21 1 Patented Apr. 23, 1968 3,379,211 COMPRESSION CONTROL VALVE Robert J. Morse, Elyria, Ohio, assignor to Bendix-Westlnghouse Automotive Air Brake Company, Elyria, Ohio, a corporation of Delaware Filed Nov. 5, 1965, Ser. No. 506,485 9 Claims. (Cl. 137-469) This invention relates to fluid pressure responsive valves and more particularly to a valve for automatically controlling the delivery or discharge side of an air compressor.

The broad object of the present invention is to provide an improved valve responsive to the delivery pressure of an air compressor and adapted to be interposed between the delivery side of a compressor and a fluid pressure receiver or reservoir to serve the combined func tions of a governor, discharge line unloader, check valve, drain valve and safety valve.

In the copending application of Valentine et al., Ser. No. 267,986, filed Mar. 26, 1963, now Patent No. 3,329154 and assigned to the same assignee as the present invention, there is disclosed a compressor discharge line control Valve which includes a piston between an inlet and delivery cavity with the piston carrying a oneway check valve which permits the passage of fluid from the inlet cavity to the delivery cavity but not in the reverse direction. At the end of the inlet cavity opposite the piston there is an exhaust port controlled by a fluid pressure responsive valve member which is normally urged to closed position by a spring surrounding a piston and the valve. Because the pressure acting on the upper and lower sides of the piston is substantially equal, when the pressure in the inlet cavity acting on the valve produces a force in excess of the spring force, the valve is first cracked, and then is moved by the pressure in the inlet cavity to its fully open position. The compressor is now unloaded and the piston and valve remain in unloading position until the reservoir pressure recedes to a predetermined low value whereupon the spring moves the piston and the valve toward their closed position and as soon as the valve is moved into its fully closed position the compressor again beings the delivery of fluid through the check valve in the piston to the reservoir.

For maximum efiiciency, it is highly desirable that the exhaust valve, after initial cracking, move to its fully opened position with a snap-action and this can be achieved by providing the valve with an added area upon which the pressure in the inlet cavity can act following initial valve cracking. An added area, while achieving snap-action opening, can some times impede the closing of the valve in that as the valve approaches its nearly closed position and while still cracked, the pressure in the inlet cavity equalizes with that across the seat and around the restricted area between the body and valve so that valve does not close positively. One of the objects of the present invention is to eliminate the foregoing undesirable characteristic by the provision of added-area means which are available and effective when the valve is being moved to open position but which automatically retracts so as not to impede movement of the valve to its closed position.

More particularly it is an object of the invention to provide in an unloading valve of the type described, means for insuring positive and eflicient movement of the unloading valve element to its open and closed positions.

Other objects and their attendant advantages will become apparent as the following description is read in conjunction with the accompanying drawings wherein:

FIG. 1 is a vertical cross-sectional view of a compressor control valve incorporating the features of the present invention;

FIG. 2 is an enlarged broken, vertical cross-sectional view showing a detail of the present invention;

FIG. 3 is a view similar to FIG. 2 but showing the parts of the invention in changed positions; and

FIG. 4 is a broken, vertical, cross-sectional view showing a modified form of the invention.

Referring now to the drawings, FIG. 1 discloses a valve including a hollow body member 10 having an interiorly threaded open top closed by a cap member 12 having an outlet or delivery port 14 therethrough which serves to connect a delivery cavity 15 in the body 10 with a fluid pressure reservoir (not shown). The body 10 has an inlet port 16 in the side thereof which is adapted to be connected to the delivery side of an air compressor with the port 16 leading to an inlet cavity 18 within the body 10 whose lower side includes a flange 20 surrounding an exhaust port 22 controlled by an exhaust or unloader valve 24 defined by a raised annular ring on the upper side of a circular disc 25 and which normally sealingly engages the underside of the flange 20 to close the exhaust port 22. The delivery cavity 15 in the body 10 is separated from the inlet cavity 18 by a piston 28 having fluid passages 30 extending therethrough whose upper ends are controlled by a check valve 32 which is normally urged on to an annular valve seat 34 by means of a spring 36 operating between the upper side of the valve 32 and a flange 38 at a lower end of the delivery port 14.

Connected to the piston 28 is a piston rod 40 which extends axially downwardly and outwardly of the exhaust port 22 and surrounding the piston rod is a compression spring 41 which operates between the inner surface of the flange 20 and the lower side of the piston 28. The lower end of the rod 40 is threaded to receive a nut 42 whose upper end bears against the lower side of an aligning member 44 engaging the lower surface of a shallow cup shaped member 46 having an upstanding annular wall 48 and received within the cup shaped member 48 is the aforementioned disc member 25 having on its upper side the annular valve member 24 which is urged to its normal closed position by the action of the spring 41 on the piston.

In accordance with the invention the member 25 is centrally counterbored to provide an enlarged central passage 52 surrounding a portion of the piston rod 40. The member 25 has also formed therein an annular groove 54 of substantial depth which is connected to the central passage 52 by a series of radial passages 56. When pressure exists in the inlet cavity 18 and hence in the groove 54 it is prevented from leaking downwardly between the inner edge of the cup shaped member 46 and the rod 40 by means of an O-ring 62 around the inner upper edge of the aligning member 44 as can be clearly seen in FIG. 1.

As can be seen particularly in FIGS. 2 and 3, the vertical wall 48 of the cup-shaped member 46 is selected so as to have .a height such that the upper edge of the wall 48 extends above the lower face of the groove 54 and received within the groove 54 is an O-ring 58 which slidingly and sealingly engages the upper and lower faces of the groove. Also received in the groove 54 outwardly of the O-ring 58 is a split expanding metal ring 60 which is expanded outwardly when sufiicient pressure operates on the O-ring 58 to expand this member radially until the ring engages the vertical wall 48 of the cup-shaped member 46 which limits the expansion of the ring 60 as shown in FIG. 2. When the pressure operating on the O-ring 58 is release-d to atmosphere the split ring 60 and the O-ring 58 retract to a free state wherein the split ring moves substantially away from the vertical wall 48 and into the groove 54 thereby providing a large clearance area between the disc 25 and the wall 66, as shown in FIG. 3.

In operation with the delivery port 14- connected to a fluid pressure reservoir and the inlet port 16 connected to a compressor, when the latter is operating it delivers fluid pressure by way of inlet port 16 to the inlet cavity 18 from which the fluid flows by way of passages 3% in the piston 28, by the check valve 32 and through the delivery port 14 to the reservoir. As the pressure builds up in the reservoir it likewise builds up in the inlet cavity 18 and because the pressure forces acting on the upper and lower sides of the piston 28 are subsantially equal, there is a resultant pressure force which operates across the area defined by the exhaust valve 24 and this same pressure also feeds through the central passage 52 and the radial passages 56 to the groove space 54 inwardly of the O-riug 58 to expand this radially outwardly until the split ring engages the vertical wall 48 of the cup shaped member 46.

As the expanding or split ring 66 expands outwardly it approaches the inner annular wall 66 in an inverted annular exhaust cavity 68 in the lower end of the body 16. It will be noted that the upper wall of the cavity 68 is also the seat for the exhaust valve 24 so that when the valve 24 is moved to open position fluid in the inlet cavity 18 flows past the valve 24 and then outwardly to atmosphere initially along the wall 66. Thus, when the split ring 60 is moved close to the wall 66 as shown in FIG. 2, a restriction 70 is provided between the wall 66 and the split ring 60 whereby the free escape of fluid to atmosphere is prevented so that it operates with substantially full force across the area or the disc outwardly on the valve 24 plus the added area defined by the upper surface of the ring 60. Thus with pressure suddenly exerted on this entire area immediately following cracking of the valve 24, the valve 24 and hence the piston 28 are moved downwardly against the upward force of the spring 41 with a positive snap action with the pressure in the inlet cavity 18 immediately receding to atmospheric and the pressure in the reservoir now acting downwardly on the piston 28 and the check valve 32 to retain the exhaust valve 24 in its fully open position so that the compressor is unloaded with any water trapped between the compressor and the inlet cavity being discharged to atmosphere as the valve 24 is moved to open position. As soon as the pressure in the inlet cavity 18 has fallen to atmospheric, the pressure operating outwardly on the O-ring 58 also recedes to atmosphere and the split ring retracts inwardly substantially to the position shown in FIG. 3.

As the pressure in the reservoir falls below -a predetermined value, the spring 41 operates on the piston 28 to move it upwardly toward the position of FIG. 1 but so long as the valve 24 is open the pressure in the inlet eavity remains at atmospheric and the split ring 60 remains in the retracted position of FIG. 3. Thus as the valve approaches its closed position the split ring 60 no longer provides an increased pressure receiving area so that there is no danger of pressure accumulating outwardly of the valve 24 as it approaches closing so as to impede its moving cleanly and positively into its fully closed position so that pressure is again delivered to the reservoir through the check valve 32 as previously explained. On closing snap action is realized by the near seating f the valve 24 which causes the pressure in cavity 18 to increase from atmosphere. Since the area of piston 28 is larger than the area of the valve 24 the result is a positive upward snap closing of the valve 24. As the pressure again builds up in the reservoir and in the inlet cavity 18 it again operates on the O-ring 58 to expand this radially outwardly to move the split ring into its restricting position of FIG. 2 in readiness to provide added area for snap action of the valve 24 as soon as it is cracked by the build up of pressure in the reservoir and in the inlet cavity 18.

The embodiment shown in FIG. 4 is functionally substantially identical to the arrangement described in FIGS.

1 through 3, and like reference characters refer to like parts, except that in lieu of a split ring there is substituted an annular garter spring 72 which expands and contracts uniformly throughout its circumference. The spring 72 is coated and filled with rubber and can be expanded outwardly by the O-ring 58 into direct engagement with the annular wall 74 of a counterbore 76 having substantially greater depth than the cavity 68 in the embodiments of FIGS. 1 and 3. As the garter spring is expanded outwardly it very nearly closes oif the upper end of a vertical relief groove 78 in the side wall 74 so that initially, following cracking of the valve 24, the fluid pressure in the cavity 18 operates on the added area defined by the outer diameter of the expanded garter spring 72 so as to move the valve and piston downwardly with a snap action until the inlet cavity 18 is in free communication through the exhaust port 22 with relief passage 78 whereupon the inlet cavity 18 recedes to atmospheric pressure and the O-ring and garter spring retract inwardly so as to provide freedom of communication entirely around the periphery of the grooved member 25 which has substantially less diameter than that of the counterbore 76. The garter spring 72 and the O-ring 58, as in the first embodiment, remain in their re tracted position until the valve 24 has moved with positive action into its closed position.

From the foregoing description, it will now be seen that the provision of means for automatically adding and subtracting motive areas in accordance with the need for such areas has been provided by the present invention and that the arrangement of the invention entirely eliminates any sponginess or slowness of response, particularly during valve closing, which may occur where an added area is present irrespective of whether the valve is to be moved to its open position, where added area is necessary, or to closed position where the added area is often undesirable. Those skilled in the art will, of course, recognize that the valve of the invention is susceptible of .a variety of changes and modifications without however, departing from the scope and spirit of the appended claims.

What is claimed:

1. A valve comprising a body having an inlet cavity connected to a source of fluid pressure, an exhaust cavity in said body, a port connecting said inlet and exhaust cavities, a valve in the exhaust cavity controlling said port and exposed at all times through said port to pres sure in said inlet cavity urging said valve to open position, resilient means urging said valve at all times to closed position in opposition to the pressure in said inlet cavity, a pressure responsive expansiole element integrally connected to said exhaust valve for movement therewith, fluid pressure conduit means connecting said element at all times with the pressure in said inlet cavity for expanding said element into close adjacency with the wall of said exhaust cavity to afford an added motive area for said valve to effect movement of same to open position with a snap action upon cracking thereof, second fluid conduit means cooperating with said expansible element for freely connecting said exhaust cavity to atmosphere after a predetermined movement of said valve and element in an opening direction, and means automatically retracting said element to a position substantially spaced from the wall of said cavity when the pressure in said inlet cavity is at a predetermined low value.

2. A valve comprising a body having an inlet cavity connected to a source of fluid pressure, an exhaust cavity having an annular side wall in said body, a port connecting said inlet and exhaust cavities, a valve in the exhaust cavity controlling said port and exposed at all times through said port to pressure in said inlet cavity urging said valve to open position, resilient means urging said valve at all times to closed position in opposition to the pressure in said inlet cavity, a pressure responsive radially expansible annular element in said exhaust cavity and integrally connected to said exhaust valve on the side thereof opposite said port and movable with said valve, fluid pressure conduit means connecting said element at all times with the pressure in said inlet cavity for expanding said element radially into close adjacency with the wall of said exhaust cavity to afford an added motive area for said valve to effect movement of the same to open position with a snap action upon cracking thereof, second fluid conduit means cooperating with said expansible element for freely connecting said exhaust cavity to atmosv phere after a predetermined movement of said valve and element in an opening direction, and means automatically retracting said element to a position substantially spaced from the wall of said cavity when the pressure in said inlet cavity is at a predetermined low value.

3. The valve of claim 2 wherein the wall of said exhaust cavity is of limited depth and where said second conduit means is afforded by spacing between said exhaust and said wall upon movement of said expansible element to a position beyond said wall.

4. The valve of claim 2 wherein the wall of said exhaust cavity is of substantial depth and wherein said second fluid conduit means comprises a groove in the wall having an outer end open to atmosphere and an inner end below which the expansible element is movable to freely connect said exhaust cavity to atmosphere.

5. A valve comprising a body having an inlet cavity connected to a source of fluid pressure, an exhaust cavity in said body, a port connecting said inlet and exhaust cavities, a valve in the exhaust cavity controlling said port and exposed at all times through said port to pressure in said inlet cavity urging said valve to open position, resilient means operating at all times on said valve to urge it to closed position, fluid pressure responsive means in said valve body operating on said valve upon movement thereof to open position to retain it opened in opposition to said resilient means so long as the pressure on said fluid pressure responsive means is above a predetermined value, a pressure responsive expansible element integrally connected to said exhaust valve for movement therewith, fluid pressure conduit means connecting said element at all times with the pressure in said inlet cavity for expanding said element into close adjacency with the wall of said exhaust cavity to afford an added motive area for said valve to effect movement of the same to open position with a snap action upon cracking thereof, second fluid conduit means cooperating with said expansible element for freely connecting said exhaust cavity to atmosphere after a predetermined movement of said valve and element in an opening direction, and means automatically retracting said element to a position substantially spaced from the wall of said cavity so as not to impede the return of said exhaust valve to closed position when the pressure on the pressure responsive element has fallen below said predetermined value.

6. In combination with a valve body including an inlet cavity having an inlet port, an exhaust cavity having an annular wall, a port interconnecting said inlet and exhaust cavities, said exhaust cavity controlling said port and responsive to pressure in said inlet cavity for movement to open position, resilient means urging said valve at all times to closed position but yielding to enable said valve to open when the force of pressure in said inlet cavity acting on said valve is above a predetermined value, and fluid pressure responsive means for retaining said valve open upon movement thereof to open position in opposition to said resilient means so long as the pressure acting upon said pressure responsive means is above a predetermined value, the invention which comprises an annular disc-like element in said exhaust cavity and integrally connected to said valve on the sid thereof opposite said port, said disc-like element having substantially less diameter than said exhaust cavity, an annular outwardly open groove through the periphery of said disclike element, a resilient expansible element in said groove and movable between a normally retracted position of substantially less diameter than said exhaust cavity to an expanded position wherein said element extends radially outwardly of said groove and into close adjacency with th side wall of said cavity, an expansible O-ring in said groove inwardly of said expansible element and slidingly and sealingly engaging the opposed side faces of said groove, and fluid passage means connecting said groove inwardly of said O-ring at all times with the pressure in said inlet cavity, and second fluid conduit means cooperating with said expansible element for freely connecting said exhaust cavity with atmosphere after predetermined movement of said valve and said element in a valve opening direction.

7. The combination of claim 6 wherein said expansible element comprises a split expansion ring.

8. The combination of claim 6 wherein said expansible element comprises a garter spring and resilient yielding material embedding and surrounding said spring.

9. The combination of claim 6 including means for positively limiting the extent of expansion of said expansible element, said means comprising a cup-shaped element of a predetermined diameter greater than said disc-like element and having an upstanding annular wall which affords an abutment for said element upon expansion thereof.

References Cited UNITED STATES PATENTS 2,507,384 5/1950 Schneck 137-108 2,585,045 2/1952 Schmidlin 137-108 X 2,749,935 6/1956 Heard 13710'8 X 3,086,548 4/1963 Galiger 137116.5 3,329,154 7/1967 Morse 137-116 WILLIAM F. ODEA, Primary Examiner.

W. H. WRIGHT, Assistant Examiner.

Claims (1)

1. A VALVE COMPRISING A BODY HAVING AN INLET CAVITY CONNECTED TO A SOURCE OF FLUID PRESSURE, AN EXHAUST CAVITY IN SAID BODY, A PORT CONNECTING SAID INLET AND EXHAUST CAVITIES, A VALVE IN THE EXHAUST CAVITY CONTROLLING SAID PORT AND EXPOSED AT ALL TIMES THROUGH SAID PORT TO PRESSURE IN SAID INLET CAVITY URGING SAID VALVE TO OPEN POSITION, RESILIENT MEANS URGING SAID VALVE AT ALL TIMES TO CLOSED POSITION IN OPPOSITION TO THE PRESSURE IN SAID INLET CAVITY, A PRESSURE RESPONSIVE EXPANSIBLE ELEMENT INTEGRALLY CONNECTED TO SAID EXHAUST VALVE FOR MOVEMENT THEREWITH, FLUID PRESSURE CONDUIT MEANS CONNECTING SAID ELEMENT AT ALL TIMES WITH THE PRESSURE IN SAID INLET CAVITY FOR EXPANDING SAID ELEMENT INTO CLOSE ADJACENCY WITH THE WALL OF SAID EXHAUST CAVITY TO AFFORD AN ADDED MOTIVE AREA FOR SAID

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