US1036886A

US1036886A - Electric pump-governor.

Info

Publication number: US1036886A
Application number: US35924107A
Authority: US
Inventors: Howard M P Murphy
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1907-02-25
Filing date: 1907-02-25
Publication date: 1912-08-27
Anticipated expiration: 1929-08-27

Description

ELM', P. MURPHR ELECTRIC PUMP GOVERNUR.

IWFLIUATION FILED FBIB.25, 1907K azmf Aug y' 3 SHEETS-SHEET awww Awy.

E. MAn 13 MURPHY, ELECTRIC PUMP GOVERNOR.

APILIGATION FILED EB.25, 190?.

Patented Aug. 272 1912.

3 SHEETS-SHEET 2.

/WTHHSSES INVENTOR i ,f/ MWL/MM .V M H, 7 j

H. M. P. MURPHY. ELECTRIC PUMP GOVERNOR.

APPLICATION FILED FEB.25,1907.

33,886. Patented Aug. 2'?. 1912.

3 SHEETS-SHEET 3.

. i o all whom t may concern:

. sTATEs PATENT OFFICE.

vHOWARD M. P. MURPHY, OF PITTSBURGH, PENNSYLVANIA, yASSIGNOR TO THE WEST- INGI-IOUSE AIR BRAKE COMPANY, F PITTSBURGH, PENNSYLVANIA, A CORPORA- TION QF PENNSYLVANIA.

ELECTRIC PUMP-GOVERNOR.

' Be it known that I, HOWARD M. P. Mim- PHY, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented new and. useful Improvements in Electric Pump-Governors, ot'which the following is a specification.

This invention relates to pump governors, and more particularly to governors for electric motor drivenv pumps, wherein the main controlling device, or switch, for opening and closing the circuit to the motor for driving the pump is operated according to the pressure produced by the pump.

The principal object of my present invention is to simplify `the construction of pressure governors of this class, wherein a main actuating piston is employed for throwing the contro-lling device, or switch, to its ditferent positions, for cutting the pump into -or out of operation; 'and having means subject to the pump pressure for controlling the supply ot fluid to and its release from the actuating piston.

Another ,object is to provide improved means, whereby the movementof the actuating piston from one position to the other shall be eiected with a quick, positive and snap-like action, to causeV a rapid and sudden shitting of the controlling device, or switch.

Another object is to provide means whereby the movement of the actuating piston from its outer position may control the release of fluid from the face ot the piston andA cause a rapid return movement.

Another object is to provide improved means, governed by the pump pressure, for rapidly supplying a large volume of fluid to the actuating piston.

Another object is to provide an improved adjustable spring mechanism opposing the pump pressure, whereby the governor may be' readily set to any desired pressure. and the range or difference between the cutting in andthe cutting out press-ures may be quickly adjusted to meet any desired conditions.

Another object is to provide improved mechanism tor controlling the governor by 'diiiereutial fluid pressures.

These objects, as well as others, arcat- Specification of Letters Patent.

Application filed February 25, 1907.

'which-- Patented Aug. 27, 191.2. serial No. 359,241;

tained by means'of the apparatus which will now bemore fully described in connection with the accompanying drawings, in

Figure 1 is a vertical sectional view of one form of governing device embodying my improvements; Fig. Q a similar sectional view, showing a modication adapted to be operated by diiierential pressures; Fig. 3 a similarsectional view showing a modification in which the two valve pistons have similar under differential fluid pressures; Fig. 5 a sectional view showing still another modiiication embodying a diaphragm and valve, the lower part of thespring box being broken away; Figy 6 a similar sectional viewwitli additional mechanism .for operating the governor undertwoditlerent lluid pressures; Figs. 7, S and 9 views of the slide valve and seat of the construction shown in Fig. 5; and Figs. 1Q, 11 and 12 corresponding views'of the slide valve andV seat of the governor construction shown in Fig.- 6.

According to the construction sho-wn in Fig. '1, the main `controlling device, or switch, 1, is connected to the actuating piston, 2, which is normally lield at its inner position in the cylinder 3 by means of the spring Ll.

Pressure from the pump or reservoir is admitted by pipe 5 to the valve piston 6, which is normally held to its seat by the adjustable spring 8, sbA that only7 a small area ot the piston 6 is then subject to the reservoir pressure. A port 9 leads from the space outside of this valve seat to the valve piston 12, which controls port 13 leading t-o the face of actuating piston 2 in cylinder 3. A by-pass groove 10 may be provided around piston 6, and a port 11 leads from the space below the piston to the port 14, which communicates with the cylinder 3 near its outer end. A

The valve piston .12 has a rib, or seat` l5,

-- which is adapted to engage gasket 16 in one position and cut off communication from po-rt 14 to the one side of said piston within the seat portion, while the stem 17 is provided with a small groove 18 forming a rcstricted passage from this space beneath valve piston to the spring chamber and cutlet port 20. The adjustable spring 19 determines the .point at which the governor cuts in.

When the actuating piston 2 is at its outer position it engages the seat 21 for making a tight joint, and it desired, a small port 23 may be provided for maintaining the pressure upon the actuating piston. this port being closed by the piston when in its inner position. The main controlling 'device, or switch mechanism, may be covered by a casing, 22.

In the normal position of the parts of the governor, as shown in the drawings, the main switch is closed and the pump is operating to raise the fluid pressure in the reservoir and through pipe 5 on the small area of vvalve piston 6, the spring. S beingfadjusted to the maximum degree of pressure at which it is desired that the pump shall cut out. When the pump pressure reaches this degree the'valve piston 6 is forcedslightly away from its seat 7 ,y thereby permitting the pressure to act upon the greater area of the face of the piston and move the, same quickly downward, and opening the supply of iuid through port 9 to valve pis# ton .12. rIvhe equalizing groove V10 is closed by the first part of the downward movement of the piston 6 and the space beneath said piston, and also beneath the valve piston 12 has a free exhaust through the large passage 14 and outlet port 211, so thatk the pressure then acting on the upper face of piston 12 moves the same rapidly downward against its seat on gasket 16 compressing the spring '19 and opening the port 13 to supply luidunder pressure to the cylinder 3 when it acts upon the piston 2 to throw the same quickly to its out-er position. This movement of the actuating piston closes the exhaust through the passage 14E and shifts the main controlling switch to its open pof sition to cut the pump out of operation. The actuating piston is then held tightly against its seat 21 and the pressure equalizing through passages 14 and 11 upon the piston 6 allows the'spring 8 to return the same to its seat 7. As the groove 1S in stem 17 maintains atmospheric pressure beneath piston 12 the parts remain in this position until the pump pressure hasl diminished to the point at which the spring 19 overcomes the fluid pressure acting on piston 12, at which time the seat 15 is slightly raised :trom the gasket 16. The iuid. pressures acting on opposite sides of the valve piston 12 are then immediately balanced, by the equalization of the reservoir pressure from the cylinder 3 through passages 13 and 14:, as restricted groove 1S is too small to permit `the escape of considerable volume of fluid, and the spring 19 returns the piston valve 12 rapidly toits inner position, thereby opening communication between ports 14 and 13. As the pressurel acting onv the piston 2 in cylinder 3 begins to fall, due to the escape of fluid through groove 18 and outlet port 20, the spring 1 moves the piston 2 away'trom its seat 21 and thereby opens a large by-pass and exhaust passage from the face of the actuating piston through ports'13 and 14: and outlet port 2&1-- to the atmosphere'. to return the piston 2 to its inner position and to throw the controlling device to its closed position with a quick, positive and snap-like action, thereby again cutting in the pump.

The ports 13 and 14 are ot large capacity,

vin order to permit the supply or release of a large volume of` fluid quickly to or from.

the cylinder 3 and thereby effect a sudden The spring then acts and positive movement 'of the piston and controlling switch from one position to the other. y f o The range of the governor, or the dierence between the cutting in and cutting out pressure may be made anything desired by the adjustment of the springs 8 and 19.

During the time that' the pump is cut out, and afterthe'valve piston 6.has returned to its seat, the pressure upon the actuating piston 2 and the valve piston 12 is maintained by the feed through the small port 23. l x

The modified construction shown in Fig.

2 is, substantially the same as that of Fig. 1

except that the valve pistons are arranged to operate horizontally instead of vertically,A and the valve piston 12 is provided with an additional small seat 25 for controlling the supply of fluid from thereservoir connec tion 5 through ports 26 and 13 to maintain the pressure instead of the small port 23 illustrated in Fig.. 1. i Fig. 2 also illustrates an additional feature of my improvement, comprising an abutment, or diaphragm, 30, subject on one side to the reservoir pressure in chamber 28 and on the other side, in chamber 29, to the pressure of another source, such as a reservoir pipe line 34, which may be employed tor connecting several reservoirs where each reservoir is'provided with a pump for furnishing compressed fluid thereto, and it is desirable that all of the pumps should operate together to raise the pressure in thel sys tem to its maximum cutting out point. The stems of the valve pistons 6 and 12 are ex tended through close fitting guides into a small chamber 27, from which leads a port 31, and the vdiaphragm 30 is provided with` va valve 33 for controlling communication from port 31 to port 32 and the atmosphere. Spring 35 normally holds the valve 33 closed. The operation of this form of my improvement, when used with a single pump and reservoir, will now be readily understood. from the foregoing description.

Whenemployed in connection with a plurality of pumps and reservoirs connected by a. reservoir pipe line, each pump and reservoir being provided with a governor, it is diilicult to adjust all the governors to cut in at exactly the same degree of pressure; but

with my imprb-ved differential pressure at-' of the governors raises the valve 83 and vents the pressure in chamber 27 on the valve stem tothe atmosphere, thereby assisting thecutting in spring 19 acting on the-valve piston 124 sutliciently to operate the governor to cut in thepump. In the same manner each p ump will be cut in by lts governor immediately after any other one of the governors cuts in, and all of the 'pumps will assist in raising the pressure of embodiment of my invention as illustrated l ber 26, 1910.

According to the modilication shown in Figs. 3 and 4, the structure is simplified by i combining the two valve pistons, 6 and 1Q,

`into one valve piston, 12, adapted to cngage the seat 7 with the small area of its upper surface subject to the reservoir pressure, and having seat 15 upon its opposite side for engaging gasket 16 when moved to the other position, In this case, the cutting cut pressure is determined by the adjustable spring 8 alone, since this spring exerts itsV force in opposition to the iiuid pressure acting upon the small area ofthe valve piston within the seat 7, while the cuttingin pressure is determined by the combined force of the two

springs

8 and 36, which is exerted in opposition to the fluid pressure acting upon the valve piston of the area within the seat 15 when the same is seated against the gasket 16. /The restricted passage from the space beneath the valve piston to the outlet port Q0 may be formed by making the stem 17 with a loose fit, as indicated in Figs. 3 and 4., or with grooves, as

shown in Figs. 1 and 2. The stemll? is of such length as to be free from, the supplemental spring 36 when the piston va'lve is in its upper position, but is adapted te engage and compress said spring uponthe movement of the piston to its opposite position,

and the range of the governor may be readily' adjusted, as desired, by varying the tension of they spring 36. The operation of thisI form of my improvement will now be readily understood.

When the pump pressure acting on the I small area of piston 12, within the seat 7, overcomes the pressure of spring 8, the valve is forced slightly from its seat and exposes' the full area of the piston to the reservoir pressure, which instantly carries the seatI 15 against the. gasket 16, compressing both springs 8 and 86, and opening the large port 13 to supply Huid in a large volume to cylinder 3 to throw the actuating piston 2 and controlling switch with a` quick and positive movement to the open position. The pistou 2 is then held against seat 21 by the reservoir pressure, which also fills the passage 14 and space around the flange 15 o valve piston 12, but cannot escape through the restricted passage to outlet port 20. Then the pressure acting on the face of the valve piston diminishes to a point less than the combined force of

springs

8 and 36, the seat 15 will be moved away from the gasket and permit an immediate equalization of fluid pressure upon opposite sides of said piston, sothat the spring 8 instantly returns the same to its position against the seat '7, at the same time allowing the discharge of fiuid from the actuating cylinder through the restricted outlet and 'port 20 to the atmosphere. As the pressure diminishes on piston 2,'the spring i starts the saine away from its seat 21, and as piston passes the port 14 it opens a large passage for therelease of fluid from the face of the piston around through ports 13 and 1st to the atmosphere, whereupon the spring 4c operates to return the piston and through the controlling switch to its closed position with a rapid and positive movement.

The additional di'lferent-ial pressure attachment shown in Fig. 4; operates substantially like that described in connection with Fig. 2, except that the diaphragm valve 33 controls the supply of fluid under pressure from the pipe line 34 througl-l the port 31 to the spring chamber at one end of the stem of the valve piston, instead of releasing' pressure from the opposite end of said stem, the result being the same in either case.

In both of these modifications, it will be noticed that the differential pressure mechanism operates to cause t-he governor to eut 1in only when the pump pressure is nearly downto the cutting in point. Wlien the increased nearly -to the cutting out point, if

the pressure upon the end of the stem of the valve piston, but this would not cause any movement of the said piston, as the reservoir pressure 1s then acting u-pon the large area to hold the piston seated on the gasket 16.

The slight additional pressure applied at the end of the stem is not therefore suliicient at this time to cause the governor to cut 1n again, consequently each governor will op? erate independently to cut out its pump, as before described.

According to the modification illustrated. in Figs. 5 to 12 of the drawings, the movable abutment subject to the pump pressure, is shown as comprising a diaphragm 37 having a slide valve 33-with ports forcontrolling the passages 13'and 14 and the supply of fiuid to and its release 'from the cylinder 3 of the actuatingpiston2. The fluid 25 pressure acting on the' diaphragm 37 is opposed by a main spring 43` in chamber 52 and the diaphragm stem 44 is adapted -to engage an additional spring 45 upon a short outward movement of said stem, although the same is no-rmally free from engagement with said additional spring when in the position shown in Figs. 5-and 6 of the drawings. The valve seat is provided with a port 39 leading` to thecyli'nder 3, where it is normally closed by valve 46 carried by piston 2, and a port 40 leading to the atmosphere, while the valve 38 has a through port 41 and a ycavity 42, with eX- tension 47. The operation of this modified form of my improvement is as follows The springs being adjusted to the desired pressures, the parts normally occupy the po-.

sit-ions shown in Figs. 5 and 6, with the coi-- trolling switch closed andthe pump in operation; when the pump pressure on the diaphragm 37 increases to such a pointias to compress the spring 43,the diaphragm and slide valve movefdownward'until the stem 44 engages the additional spring 45, but this movement is not suflicient to connect the through port 41 of the valve with theport 13 in the seat, although it doesopen the port 39 and closes communication between the exhaust. port 40 and the extension 47 of the cavity 42. It is therefore necessary for the fluid pressure to rise to such a point as to compress both springs 43 and 45, in order to bring port `41` over port 13, as indicated in Figs. 7 and 10, and supply fluidl to operate the piston 2, for, althoughthe port 39 was previously opened, the pressure of the spring 4 holding valve 46 to its seat, yprevents the admission of fluid through port 39 to cylinder 3 until the piston 2 moves .outward and 65 carriesvalve 46 away from its seat. As

large port 39 to supply air to the actuating soon as the piston 2 starts outward under the pressure admitted through ports 41 and 13, the valve 46 opens the large port 39 for supplying alarge volume of fluid rapidly to the cylinder' 3, thereby elfecting a quicio and 70 positive'outward movement of the piston against the spring 4, and throwing the -controlling switch to its open position. The piston 2 isjthen held 'against its seat 21 by the fluid pressure. Y

It should lbe understood that 1 do not claim as my invention the feature, described in connection with the modification shown i-n Figs. 5 to 12 inclusive, of providing a piston in large volume upon upward movement thereof, this feature being the invention of W. V` Turner and the subject-matter of Patent No. 950,737, issued March 1, 1910. As the pump pressure acting on dia,- phragm 37 diminishes, the combined forces of the springs 43. and 45 operate to move the valve upward until the stem 44 is just free from engagement with spring 45 and the port 13 isl clcsed. The spring 43'then acts 90 alone against the fluid pressure upon the diaphragm, and as this pressure continues to fall the single spring moves the valve to its upper position, as indicated in Fig. 5, in which the port 39 is. closed and the cavity 42 connects ports 13 and 14, while the eXtension 4i communicates, with the exhaust port 40 and permits the discharge from the cylinder 3 through

ports

13, 47 and 40 to the atmosphere. I

As the pressure is reduced o n the face of the pistony 2, the spring 4 moves the piston away from its seat 21 and opens the port14 to the space behindthe piston and to the atmosphere, and as ports 13 and 14 are then con- 105 nected through cavity42 a large passage is provided for the rapid exhaust of fluid from the cylinder 3 upon the face of the piston 2. The actuating piston is therefore returned to its inner position with a rapid and posi- 11()` tive movement, thereby closing the controlling switch and cut-ting in the pump. In this manner the movement of the actuating piston serves lto control the supply and the l release of Huid to and from thelcylinder, whereby a more rapid and sudden action is secured in shifting the controlling switch from one position to the other.

The spring 43 is adjusted to the desired minimum degree of pump pressure, since the spring by itself determines the point at which'the governor is to` cut in, while the combined force of the springs 43 and 45 determines the desired maximum degree of pressure at which the governor cuts out the pump, but the range, or difference between these pressures,l may be readily varied to suit any given condition by merelv adjust-- ing the tension of the. additional spring 45.

The differential pressure attachment 13o similar manner to` that described in connection with Fig. 4, except thatl the diaphragm valve 33 controls the supply of Huid under pressure from the reservoir through

ports

48 and 49 to the chamber 52 beneath the main diaphragmBT for assisting the spring 43 to move the slide valve to its cutting in position. j

lt will be noticed that the

ports

48 and 49 are connected by the cavity 50 only when the valveis at or near its cutting in position, while this communication is cut off when the valve is in the opposite position, as indicated lin Fig. l0. By this means the differential pressure mechanism can operate to cause a governor to eut in only when the pressure is low and the governor is near to its cutting in point, but will Ahave no eifect upon the governor after the pressure has increased toward the maximum sufiiciently to move the valve to disconnect the ports 4S and 49.

. mentto operate the controlling switch with a quick, snap-like action; also at the time of cutting in, that the preliminary inward' movement of the actuating piston operates kto control the pressure intits cylinder by opening a large exhaust passage for the escape of fluid from the faceyof said piston and thereby permits the spring to throwthe piston 'and controlling switch' to the other position with a quick andpositive movement.

shown iii-Fig. 3, has the further advantage of being extremely simple in structure, 'hav-v ingy but a single movable abutment or valve piston with two springs, for controlling the supply of fluid to and its release from the cylinder of the actuating piston, which structure is found to be very durable and reliable in its operationin actual practice.

Having new described my invention, what l claim as new, and desire to secure by Letters atent, is :M

l. A pump governor comprising` a pump controlling device, an actuating piston therefor., a valve piston for controlling the fluid pressure on said actuating piston having a s t and subject inthe seated position to pu mp pressure in one direction and in the i. osite direction to the pressure of an ad- The preferred form,` of construction, as`

justable spring and a `chamber having a restricted exhaust port, and means adapted 2. A pump governor comprising a pump controlling device, an actuating piston theretor, a valve piston for supplying and releasing fluid to and from said piston to operate the same having aseated position and subject to pump pressure in one direction and in the opposite direction to spring pressure and the pressure of a chamber having a restricted exhaust port, the preliminary movement of said nvalve piston from its seated position being adapted to admit fluid to said chamber to acceleratethe movement thereof, and means adapted in another position of the valve piston to open a larve port for permitting the free exhaust of air leaking into said chamber.

8. A pump governor comprising a pump controlling device, an actuating piston therefor, a valve piston mechanism for varying the Iiuid pressure on said actuating piston and subject on one side to pump pressure tending to move same to one position and on the opposite side to spring pressure and the pressure of a chamber having restricted exhaust p ort and tending to move the same to the opposite position, the preliminary movement of said valve piston mechanism from the first position being adapted to admit fluid to said chamber to effect the positive movement thereof and the preliminary movement from the second position being adapted to expose a larger area of same to pump pressure to facilitate the quick movement thereof, and means for opening' a vent port to said `chamber in the ,last mentioned position to permit the free exhaust of fluid leaking into said chamber.

4. A pump governor comprising a pump controlling device, a piston for actuating same, a valve piston mechanismY subject to spring pressure on one side and to pump pressure on the opposite side for controlling the supply andrelease of fluid to and from said actuating piston and having a seat in one direction exposing a small area thereof to pump pressure and the remaining area to atmospheric pressure through a restricted port and a seat in the opposite direction exposinga portion of the area thereof to atmospheric pressure through a restricted port.

5. A pump governor comprising a pump controlling device, a piston for actuating same, a valve piston mechanism subject to pump pressure for controlling the pressure on said actuating piston, a spring for opposing the pump pressure on said valve piston mechanism toV determine the cutting outpoint and an additional spring adapted to act With the outer spring to determine the from another position, for controlling thek admission and release of fluid to and from said cylinder.

v. 7. A pump governor comprising a pump controlling device,'a piston and cylinder for actuating saine, and a valve piston mechanism for controlling the fluid pressure to operate said piston subject in one direction to pump pressure and in the opposite direction to one degree of spring resistance in the "movement from one position, and to' another degree of spring resistance inthe movement from another position, for governing the operating fluid pressure in said cylinder.

8. A pump governor comprising a pump controlling device, a piston and cylinder for actuating saine, and 'a valve piston mechanism for controlling the fluid pressure to operate said piston subject in one direction to pump pressure and in the opposite direction to the resistance of tvvo adjustable springs when -in one position and to the resistance of one of said adjustable springs When in-another position.

9. A pressure governor for pumps comprising a pump controlling device, a pistonl for operating same, a movable valve piston device adapted to seat in opposite directions and subject on one side to pump pressure for controlling the fluid pressure for .operating said piston, an adjustable spring for opposing the pump pressure on said valve piston device and a second adjustable spring adapted to act on said valve piston device upon movement from one seat.

10. A pump governor comprising a controlling device, a piston for actuating same, a valve piston having a small area subject to pump pressure When seated in one position, a, spring for opposing the pump pres-A sure on said valve piston, said valve piston being adapted to expose a larger area to fluid pressure upon movement away from its seat, and means for maintaining the larger area at` atmospheric pressure When the valve piston is on its seat.

11. A pump governor, comprising a main controlling device, a piston for actuating the Y saine, mechanism subject to the pump pressure for supplying and releasing fluid to and from the actuating piston, and means governed by the movement of said actuatof said piston.

13.y A pump governor, comprising a main controlling device, a piston for actuating the same, a valve piste-n adapted to be seated in one position by the pump pressure and to control 4the release of fluid from the actu ating piston, and means for effecting a quick return movement of said valve piston as it moves away from its seat. c

14. A pump governor, comprising a main controlling device, a piston operated by fluid under pressure for actuating the same, a valve mechanism subject to the opposing forces of the pump pressure and an adjustable spring for controlling the release of fluid from said actuating piston, and means governed bythe movementI of said piston for further controlling the release of fluid therefrom.

15. A pump' governor comprising a main controlling device, a piston for actuating the same, a valve piston subject to the opposing pressures of the 'pump and a spring -t'or controlling the supply and release of fluid to and from said actuating piston, said valve piston having oppositev seated positions and being adapted to expose different, p

restricted areas to the pump pressure in said opposite positions.

'16. A pump governor, comprising` a main controlling device, a cylinder and piston for actuating the same, means for supplying fluid to and releasing it from said cylinder, and a release passage communicating with said cylinder near its outer end andadaptcd to be openedby the preliminary movement of said piston from its outer position.

17. A pump governor, comprising a main controlling device, a cylinder and piston for' actuating the same, a release passage leading from the inner end of Said cylinder to a point near its outer end and adapted to be opened by the preliminary movement of the piston from its outer posit-ion, and a valve mechanism operating in response to variations iii the pump pressure for also controlling said release passa-ge.v

18'. A pump governor, comprising a main controlling device, a cylinder and p istoii for actuating the same, a valve piston subject to the pump pressure for controlling the pressure in said cylinder and having a seat in one position, and means for balancing the fluid pressures upon said piston when it moves away from this position.

19. A pump governor, comprising a main controlling device, a cylinder and piston for pressure in said cylinder and'having a seat,

in one position, a restricted discharge out- 'let from the seat side of said piston, and

means for opening` communication from the actuating cylinder to said scat side of t-he valve piston when said valve piston moves to its opposite position.

20. A pump governor, comprising a main controlling device, a cylinder and piston for actuating' the same, a movable abutment subjectto the pump pressure for controlling the pressure in said cylinder, a spring constantly acting on said abutment in opposition to the pump pressure, and an additional spring adapted to act upon said abutment in one position only.

21. A pump governor, comprising a main controlling device, a -cylinder and piston for actuating the same, a. valve piston for controlling the pressure in said cylinder and having differential areas subject to the pump pressure in its different positions, a spring acting in opposition to the pump pressure to determine the cutting out point, and an additional spring acting in conjunction with the other spring to determine the cuttingin point.

22. A pump governor, comprising a main controlling device, a piston for actuating the same, a'valve piston mechanism operated by the pump pressure on one side for supplying fluid to said actuating piston, a free exhaust passage leading from the other side of said valve piston, and means 'for controlling said exhaust passage by the movement of the actuating piston.

23.v A pump governor, comprising a main controlling device, a cylinder and piston for actuating the same, a valve mechanism subject to the opposing forces of the pump pressure and a spring for controlling the release of fluid from said cylinder to cut in the pump, and a differential pressure mechanism subject to two opposing fluid pressures for assisting the spring to cut the governor in only when the pump pressure is nearly at the cutting .in point.

Q4. A pump governor, comprising a main controlling device, a cylinder and piston for actuating the same, a valve mechanism subject to the opposing forces of the pump pressure and a spring for controlling the release of fluidy from said cylinder to out in the pump, and a ldieren'tial pressure mechanism having a diaphragm subject t0 two opposing fluid pressures and a valve operated thereby for controlling a fluid pressure, to cause the governor to cut in only when the pump pressure is nearly at the cuttingv in point.

25. In a pump governor, the combination, with a main controlling device and a cylinder and piston for actuating the same, of a valve piston subject to the opposin@r forces of the pump pressure and a spring or controlling the pressure in said cylinder, and a differential pressure mechanism having an abutment and valve operated by opposing fluid pressures to supply fluid to act upon the stem of the valve piston and assist the spring to move said valve to its cutting in position.

26. A pressure governor comprising a controlling device, an actuating piston therefor, valve means governed. by the pump pressure for supplying fluid to operate said piston, and means operated by the movement of the piston for varying the pressure on one side thereof, to cause the quick movement of same.

27. A pressure governor comprising a controlling device, an actuating piston therefor, valve means governed by the pump pressure for supplying fluid to operate said piston, and means operated by the movement of the piston to cause the pump to cutv in, for varying the pressure on one side of the piston to cause the sudden movement thereof.

28. A pressure governor comprising a controlling device, an actuating piston therefor, `valve means governed by the pump pressure for supplying fluid to operate said piston, and. means operating upon the initial movementof the piston in the direction to cause the pump to cut'in, for venting` fluid from one side of the piston to thereby effect the sudden movement thereof.

In testimony whereof I have hereunto set my hand.

HOVARD M. P. MURPHY.

llf'itnesses R. F. EMnRY, J. B. MACDONALD.

esl