US2065199A

US2065199A - Unloader governor device

Info

Publication number: US2065199A
Application number: US662713A
Authority: US
Inventors: Everett P Sexton
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1933-03-25
Filing date: 1933-03-25
Publication date: 1936-12-22
Anticipated expiration: 1953-12-22

Description

Dec. 22, 1936. p, X- 2,065,199

UNLOADER GOVERNOR DEVICE Filed March 25, 1935 I.\'I 'ENTOR. EVERETT P. SEXTON .4 TTORNEY.

Patented Dec. 22, 1936 UNITED STATES PATENT OFFICE UNLOADER GOVERNOR DEVICE Application March 25, 1933, Serial No. 862,713

This invention relates to fluid compressors, and more particularly to means for controlling the loading and unloading of the compressor.

With a continuously operating compressor, there is a tendency for the storage reservoir to become overcharged unless means are provided for unloading the compressor when the pressure of the fluid in the reservoir attains the predetermined amount.

It has heretofore been proposed to provide a fluid pressure actuated unloading device for compressors in which is incorporated a flexible diaphragm for operating a lever which, in turn, acts on the unloading valve of the compressor to unseat the same, thereby permitting the compressed fluid to pass to the atmosphere instead of to the reservoir.

It has also heretofore been proposed to provide a governor device which is adapted to be connected to the unloading mechanism of a compressor and also to the reservoir which is supplied with fluid under pressure by the compressor, so as to automatically effect the operation of the compressor unloading mechanism when the pressure of the fluid in the reservoir exceeds a predetermined amount.

The principal object of my invention is to provide an improved governor device of the above character which is simple in construction and I positive in action, which has few operating parts and which is adjustable, so as to be operated by various pressures.

In the accompanying drawing, the single flgure is a sectional diagrammatic view of a portion of a fluid compressor having associated therewith an unloading means and a compressor unloader governor constructed in accordance with the invention.

Referring to the drawing, the governor device may be used in connection with a compressor comprising a cylinder l, shown in part, and having a cylinder head 2 provided with a valve chamber 3, containing the usual discharge valve 4, for controlling communication from the fluid compressor to the usual storage reservoir 5, which is connected to the valve chamber 3 by a pipe 6.

An unloading valve 1' controls communication from the compressor cylinder i to the atmosphere, said valve having an operating stem 8 which extends through a bore in the cylinder head 2 and which carries at its outer end a spring follower 9 which is subject to the pressure of a coil spring Ill acting through said stem to urge the valve 1 to its seat.

Pivotally mounted on a pin ll carried by the head 2 is a lever l2 having a long arm l3 which is adapted to engage the end of the valve stem 8.

The short arm ll of the lever I2 is adapted to engage the end of a stem amociated with a diaphragm follower plate l6, which is actuated 5 by a diaphragm I I. The chamber l8 in the cylinder head 2, at one sideiof the diaphragm I1, is connected to a pipe l9, which leads to the improved governor device, for a purpose to be fullydescribed hereinafter.

The governor device may comprise a casing having a valve chamber 2| containing a slide valve 22, which chamber is continuously connected to the pipe 6 through a pipe 23. Said slide valve is provided with a cavity 24 and is adapted 15 to cooperate with a valve seat 25 provided with ports, as will be hereinafter described. The slide valve 22 is operatively connected to a stem 50, said slide valve and stem being adapted to be operated through the medium of spaced flexible 20

diaphragms

26, 21 and 28 which are secured in the casing, the area of the diaphragm 26 being greater than that of the diaphragm 21, which in turn, has a greater area than that of the diaphragm 23. 5

The flexible diaphragm 26 separates the slide valve chamber 2| from a chamber 29 which is constantly connected to the atmosphere through a I passage 30, said diaphragm being clamped between a flange 3|, provided at one end of the 30 stem 50, and a follower plate 32, through the medium of a headed screw-33 which has screwthreaded engagement with the stem 50, there being a member 34 clamped to the follower by means of said screw. 35

Contained in the chamber 29 and interposed between and engaging the member 34 and an adjusting nut 35 having screw-threaded engagement'with the casing, is a coil spring 36. The adjusting nut 35 may be locked in position by 40 means of a locking member 31 which has screwthreaded engagement with said nut and is adapted to abut the casing 23.

One side of the diaphragm 21 engages a flange 38 provided at the other end of the stem 50. Spaced from the diaphragm 21 by means of a follower plate 48 is a diaphragm 28, and engaging the outer face of the diaphragm 28 is a follower plate 39. Extending through said follower plates and through said diaphragms and having screw- 60 threaded connection with the stem 50, is a headed screw 40 by means of which said diaphragms are secured together and to the stem 50.

Intermediate the

diaphragms

21 and 28 is a chamber II which is continuously connected by a passage 42 to a passage 43 which connects with glee pipe I! and also leads to the slide valve seat The diaphragm 28 separates the chamber 4| from a chamber 44 which is continuously connected to the atmosphere through a passage 45.

In operation, assuming that the nut 36 has been adjusted for the pressure at which it is desired to unload the compressor and that the pressure of the fluid in the slide valve chamber 2| and in the connected reservoir 5 is below this pressure, the spring 36 will act to maintain the

diaphragms

26, 21 and 28 and the slide valve 22 in the position shown in the drawing, in which the diaphragm follower plate 3| engages the stop shoulders 46 provided in the casing 26 and in which the passage 43 is connected through the cavity 24 in the slide valve 22 to an atmospheric passage 41. Since the chamber 4| is connected by the passage 42 to the passage 43 and since the chamber l8 in the unloading device is also connected to the passage 43 by the pipe l3, said chambers are connected to the atmosphere in the position of the slide valve 22 shown in the drawing.

The chamber l8 being connected to the atmosphere, the diaphragm I1 will not cause the lever l2 to exert any appreciable pressure on the stem 6 of the unloading valve, with the result that the spring III will hold said valve seated.

When the pressure of the fluid supplied by the compressor to the reservoir 5 and to the connected slide valve chamber 2| has increased to a point when the pressure exerted by the fluid in said chamber on the right hand face of the diaphragm 26 exceeds the pressure of the spring 36 plus the pressure exerted by the fluid in the chamber 2| on the left hand face of the diaphragm 21, the

diaphragms

26, 21 and 23 and hand face of the diaphragm 21 approaches equalization with the pressure of the fluid in chamber 2| acting on the opposite face of said diaphragm, the pressure of the fluid in chamber 2| acting on the right hand face of the diaphragm 26 will'become increasingly effective, with the result that the

diaphragms

26, 21 and 28, with the stem 50 and the slide valve 22, will be moved positively to the full cut-out position, in which the follower plate 38 engages a shoulder 43 provided in the casing 20 and in which the passage 43 is fully open to the slide valve chamber 2|.

It will be noted that the pressure of the fluid in chamber 4| also acts on the diaphragm 28. but since said diaphragm has a smaller area than that of the diaphragm 21, there will be an unbalanced pressure of fluid in chamber 4|, due to the differential area of the diaphragm 21, which acts on the diaphragm 21 to urge same toward the left.

With the passage 43 opened to the valve chamber 2|, fluid under pressure is supplied from the reservoir 5 to the diaphragm chamber I8 through pipe 6, pipe 23, chamber 2|, passage 43, and pipe so that the lever I2 is actuated to cause the stem 3 to move downwardly and thereby unseat the valve 1. The compressing cylinder I being then opened to the atmosphere, the compressor operates without compressing fluid into the reservoir 6.

When the fluid pressure in the reservoir 6 and in the connected chamber 2| has fallen to a point where the pressure of the spring 36 acting on the left hand face of the diaphragm 26 exceeds the pressure of fluid acting in chamber 2| on the differential area of diaphragm 26 and in chamber 4| on the differential area of diaphragm 21, the diaphragms 26, 21 and 26, with the stem 66 and the slide valve 22, will begin to move in a direction toward the right hand. As this movement progresses, the slide valve will cut oil. communication from the chamber 2| to the chamber 4| by way of

passages

43 and 42, and the cavity 24 in said slide valve will connect passage 43 to the atmospheric passage 41. With this connection established, the chamber 4| will be vented to the atmosphere through the

passages

42 and 43, cav-' ity 24, and the passage 41. The venting of fluid under pressure from chamber 4| reduces the differential fluid pressure acting in chamber 4| on diaphragm 21, so that the parts will move positively to their right hand, or cut-in position, in

which the diaphragm follower 3| engages the shoulder 46 and the passage 43 is fully open to the passage 41, as shown in the drawing. It will be noted that with the chamber 4| vented, the diaphragm 28 becomes ineffective, since the chamber 44 is also vented.

I With the slide valve 22 in the cut-in position, wherein the passage 43 is connected to the atmosphere, as above described, fluid is vented from the diaphragm chamber l8 through the pipe l9, passage 43, cavity 24 in the slide valve and the atmospheric passage 41. With the pressure thus relieved from the arm H of the lever i2, the spring III will act to shift the valve 1 upwardly to its seat. The compressor then operates to compress fluid into the reservoir 5.

It will be understood that the cutting-out pressure ofthe governor device is determined by the pressure exerted by the spring 36, combined with the relation existing between the areas of the diaphragms 26 and 21, and, that the cutting-in pressure is determined by the pressure exerted by said spring, combined with the relation existing between the areas of the diaphragms 26 and 28. To adjust the spring 36, the member 31 is unscrewed from the nut 35, which is then turned as required to establish the desired cutting-in pressure or the desired cutting-out pressure.

It will be apparent from the foregoing that I have provided an unloader governor device which is simple in construction and positive in action.

While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its'scope to that embodiment or otherwise than by the terms of the appended claims.

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

1. A device for controlling the operation of a fluid compressor unloader, comprising a plurality of interconnected movable abutments, tensioned biasing means for urging said abutments in one direction, said abutments being differentially subjected to the pressure of fluid compressed by the compressor and thereby urged in the opposite directlon, valve means operably responsive to the movement of said abutments occasioned by variations in the fluid pressure for controlling the operation of the unloader, and means for varying the tension of said biasing means to vary the force applied by said biasing means to said abutments.

2. A device for controllingthe operation of a fluid compressor unloader, comprising a plurality of interconnected movable abutments, spring biasing means for urging said abutments in one direction, stop means adapted to be engaged by one of said abutments for limiting the movement of said abutments in said one direction, said abutments being subjected to the pressure of fluid compressed by the compressor and thereby urged in the opposite direction, stop means adapted to be engaged by another of said abutments for limiting the movement of said abutments in said opposite direction, and valve means operated by movement of said abutments occas oned by variations in the fluid pressure for establishing a communication through which fluid under pressure is vented from the unloader when said abutments are moved to their limit in the said one direction and for establishing a communication through which fluid under pressure is supplied to the unloader when said abutments are moved to their limit in the said opposite direction, whereby to control operation of the unloader.

3. A device for controlling the operation of a fluid compressor unloader, comprising a pair of connected movable abutments of different areas and having a chamber therebetween, biasing means constantly urging the abutments in one direction. said abutments being constantly urged in the opposite direction in opposition to said biasing means by the differential force of fluid acting on said abutments within said chamber,

and valve means operated to diflerent positions by said abutments upon variations in the pressure in said chamber, said valve means being effective in one position thereof to establish a communication through which fluid under pressure is vented to atmosphere from the compressor unloader and effective in a diiferent position to establish a communication through which fluid under pressure is supplied to the unloader. whereby to control loading and unloading of the compressor.

4. A device for controlling the operation of a fluid compressor unloader, comprising a pair of connected movable abutments of different areas and having a chamber therebetween, biasing means constantly urging the abutments in one direction, said abutments being constantly urged in the opposite direction in opposition to said biasing means by the differential force of fluid under pressure compressed by the compressor and acting on said abutments within said chamber, and valve means operated to different positions by said abutments upon variations in the pressure in said chamber, said valve means being effective in one position thereof to establish a communication through which fluid under pressure is vented to atmosphere from the compressor unloader to cause loading of the compressor and effective in a different position to establish a communication through which fluid under pressure is supplied to the unloader to cause unloading of the compressor. 1

5. A device for controlling the operation of a fluid compressor unloader, comprising a pair of connected movable abutments of difierent areas and having a chamber therebetween, biasing means constantly urging the abutments in one direction, said abutments being constantly urged in the opposite direction in opposition to said biasing means by the difierential force of fluid under pressure compressed by the compressor and acting on said abutments within said cham-' ber, and valve means operated to diilerent positions by said abutments upon variations in the pressure in said chamber, said valve means being efiective in one position thereof to establish a communication through which fluid under pressure is vented to atmosphere from the compressor unloader to cause loading of the compressor and effective in a diiferent position to establish a communication through which fluid under pressure is supplied from said chamber to the unloader to cause unloading of the compressor.

6. A device for controlling the operation of a fluid compressor unloader, comprising a pair of connected movable abutments of different areas and having a chamber therebetween, biasing means constantly urging the abutments in one direction, said abutments being constantly urged in the opposite direction in opposition to said biasing means by the diiiferential force of fluid under pressure compressed by the compressor and acting on said abutments within said chamber, valve means having one position in which it establishes a communication through which fluid under pressure is vented from the unloader to cause loading of the compressor and having a difierent position in which it establishes a communication through which fluid under pressure is supplied to the unloader to cause unloading of the compressor, said valve means being moved from said one position toward said different position upon movement of the abutments in said opposite direction occasioned by an increase in the pressure in said chamber to a certain uniform pressure, and means efi'ective upon movement of said valve means from said one position toward said different position to cause an additional force to be imposed on the abutments urging them in said opposite direction so that said valve means is moved positively to said different position and so that movement of the abutments in said one direction to return the valve means toward the said one position is prevented until the pressure of the fluid in said chamber has reduced to a second certain uniform pressure which is less than the flrst said certain uniform pressure.

7. A device for controlling the operation of a fluid compressor unloader, comprising a pair of connected movable abutments of diiferent areas and having a chamber therebetween, biasing means constantly urging the abutments in one direction, said'abutments being constantly urged in the opposite direction in opposition to said biasing means by the differential force of fluid under pressure compressed by the compressor and acting on said abutments within said chamber, valve means having one position in which it establishes a communication through which fluid under pressure is vented from the unloader to cause loading of the compressor and having a said difierent position to cause an additionalforce to be imposed on the abutments urging them in said opposite direction so that said valve means is moved positively to said different position and so that movement of the abutments in said one direction to return the valve means toward the said one position is prevented until the pressure of the fluid in said chamber has reduced to a second certain uniform pressure which is less than the first said certain uniform pressure, said last means being effective upon return of said valve means toward said one position to cause removal of the additional force so that said valve means is returned positively to said one position and so that the valve means will not, be moved toward the said different position thereof until the pressure in said chamber has again increased to the first said certain uniform pressure.

' 8. A device for controlling the operation of a fluid compressor unloader, comprising a pair of connected movable abutments of different areas and having a chamber therebetween, biasing means constantly urging the abutments in one direction, said abutments being constantly urged in the opposite direction in opposition to said biasing means by the differential force of fluid under pressure compressed by the compressor and acting on said abutments within said chamber, and valve means having one position in which it establishes a communication through which fluid under pressure is vented from the unloader to cause loading of the compressor and having a different position in which it establishes a communication through which fluid under pressure is supplied to the unloader to cause unloading of the compressor, said valve means being moved from said one position toward said difierent position upon movement of the abutments in said opposite direction occasioned by an increase in the pressure in said chamber to a certain uniform pressure, said valve means being effective upon movement toward said different position thereof to establish a communication through which fluid under pressure is supplied to act on .the outer face of the smaller of said abutments to increase the force opposing said biasing means so that said valve means is moved positively to said different position and so that movement'of said abutments in the said one direction to return the valve means to said one position is prevented until the pressure in said chamber is reduced to a second certain uniform pressure which is less than the first said certain uniform pressure;

9. A device for controlling the operation of a fluid compressor unloader, comprising a pair of connected movable abutments of different areas and having a chamber therebetween, biasing means constantly urging the abutments in one direction, said abutments being constantly urged in the opposite direction in opposition to said biasing means by the differential force of fluid under pressure compressed by the compressor and acting on said abutments within said chamber, and valve means having one position in which it establishes a communication through which fluid under pressure is vented from the unloader to cause loading of the compressor and having a different position in which it establishes a communication through which fluid under pressure is supplied to the unloader to cause unloading of the compressor, said valve means being moved from said one position toward said different position upon movement of the abutments in said opposite: direction occasioned by an increase in the pressure in said chamber to a certain uniform pressure, said valve means being effective upon movement toward said different position thereof to establish acommunication through which fluid under pressure is supplied to act on the outer face of the smaller of said abutments to increase the force opposing said biasing means so that said valve means is moved positively to said diiferent position and so that movement of said abutments in the said one direction-to return the valve means to said one position is prevented until the pressure in said chamber-is reduced to a second certain uniform pressure which is less than the first said certain uniform pressure and effective upon movementtoward the said one position thereof to establish a communication through which fluid under pressure is vented from the outer face of the smaller abutment so that said valve means is moved positively to said one position and so that said abutments will not be moved in the said opposite direction to move the said valve means from said one position toward said different position until the pressure in said chamber again increases to said certain uniform pressure.

10. A device for controlling the operation of a fluid compressor unloader, comprising a pair of connected movable abutments of different areas and having a chamber therebetween, biasing means constantly urgirfg the said abutments in one direction, said abutments being urged in the opposite direction in opposition to said biasing means by the differential force of the fluid pressure acting in said chamber on said abutments, valve means operated to different positions by said abutments upon variations in the pressure of fluid in the said chamber, said valve means being effective in one position thereof to establish a communication through which fluid under pressure is released from the unloader to effect loading of the compressor and a communication through which the outer face of the smaller of the abutments is opened to atmosphere, said abutments being ,moved in said opposite direction upon an increase in the pressure in said chamber to a certain uniform pressure to move said valve means to a second position wherein it establishes a communication through which fluid under pressure is supplied to the unloader to cause it to unload the compressor and a communication through which fluid under pressure is supplied to act on the outer face of the smaller of said abutments and increase the force urging said abutments in said opposite direction.

11. A device for controlling the operation of a fluid compressor unloader, comprising three axially disposed connected movable abutments of different areas respectively, a first chamber between one end abutment and the intermediate abutment, a second chamber between said intermediate abutment and the other end abutment, biasing means constantly urging said abutments in one direction, said abutments being constant ly urged in the opposite direction in opposition to said biasing means by the differential force of fluid under pressure compressed by the compressor and acting in said first chamber on said one end abutment and said intermediate abutment, and valve means operated by the abutments upon an increase in the pressure of the fluid in said first chamber to a certain uniform pressure from one position, in which it establishes a communication through which fluid under pressure is vented from the unloader to cause loading of the compressor, to a second position, in which it establishes a communication through which fluid under pressure is supplied to the unloader to cause unloading of the compressor, said valve means being efiective in said one position to establish a communication through which said second chamber is vented to the atmosphere and eifective in said second position to establish a communication through which fluid under pressure is supplied to said second chamber, the differential force of the fluid under pressure acting in said second chamber on the said intermediate abutment and the said other end abutment being efiective to urge the abutments in the said opposite direction in opposition to said biasing means whereby the said biasing means is ineffective to return said abutments in said one direction to move the valve means from the second position thereof to the said one position thereof until the pressure of the fluid in the said first chamber reduces to a second certain uniform pressure which is less than the first said certain uniform pressure.

12. A device for controlling the operation of a fluid compressor unloader, comprising three coaxially disposed connected movable abutments of different areas respectively, a first chamber between one end abutment and the intermediate abutment, a second chamber between said intermediate abutment and the other end abutment, biasing means constantly urging said abutments in one direction, said abutments being constantly urged in the opposite direction in opposition to said biasing means by the difierential force of fluid under pressure compressed by the compressor and acting in said first chamber on said one end abutment and said intermediate abutment, and valve means operated by the abutments upon an increase in the pressure of the fluid in said first chamber to a certain uniform pressure from one position, in which it establishes a communication through which fiuid under pressure is vented from the unloader to cause loading of the compressor, to a second position, in which it establishes a communication through which fiuid under pressure is supplied to the unloader to cause unloading of the compressor, said valve means being efiective in said one position to establish a communication through which said second chamber is vented to the atmosphere and effective in said second position to establish a communication through which fluid under pressure is supplied from said first chamber to said second chamber, the difierential force of the fluid under pressure acting in said second chamber on the said intermediate abutment and the said other end abutment being efiective to urge the abutments in the said opposite direction in opposition to said biasing means whereby the said biasing means is ineifective to return said abutments in said one direction to move the valve means from the second position thereof to the said one position thereof until the pressure of the fluid in the said first chamber reduces to a second certain uniform pressure which is less than the first said certain uniform pressure.

EVERETT P. SEXTON.