US2527728A

US2527728A - Pumping control system

Info

Publication number: US2527728A
Application number: US544949A
Authority: US
Inventors: Harrison B Hoefer
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-07-14
Filing date: 1944-07-14
Publication date: 1950-10-31
Anticipated expiration: 1967-10-31

Description

Patented Oct. 31, 1950 UNITED STATES- PUMPING CONTROL SYSTEM Harrison B. Hoefcr, Milwaukee, Wis. Application July 14, 1944, Serial No. 544,949

5 Claims. .1

This invention relates to-controls for pumping systems particularly of large capacity such for instance as pumping systems for municipal water .works.

Large centrifugal pumps are today quite extensively employed in systems of this type for supplying water against the substantial pressures normally maintained therein. The water from from the pump is ordinarily transmitted through a large automatic valve that functions quite satisfactorily under normal operating conditions. But this valve, as heretofore equipped, relies for operation upon the pressure and flow conditionsdeveloped by the pump and, in the event of pump failure, cannot be safely depended upon to check the resulting reverse flow or back surge with the promptness required to prevent serious consequences.

An object of the present invention is to provide a more positive control for the automatic valve in systems of this type so as to effect a more reliable operation thereof. This I have accomplished by a' control arrangement for the valve involving an element mechanically connected with the pump and directly responsive to the speed of operation thereof.

Other more specific objects and advantages will appear, expressed or implied, from the following description of an illustrative embodiment of the present invention.

In the accompanying drawings:

Figure 1 is a diagrammatic view of a control system embodying the present invention.

Fig. 2 is a sectional view on a larger scale of the governor controlled valve and associated parts included in Fig. l.

The control system selected for illustration is shown applied to a conventional pumping system, including a large centrifugal pump III that supplies water through a large valve ll into a main I2. The valve II is a well known type of rotary valve, commercially known as a cone valve, which is actuated and controlled by an hydraulic servo-motor l3 with which such valves are commonly equipped. The piston I4 of the servo-motor is shown connected to the valve actuating lever l5 through which the valve ll may be rotated into open. position from the closed position shown.

In this instance the servo-motor I3 is controlled by, a four-way valve l6 which is actuated and controlled by a centrifugal governor I I driven by the pump l through a one-way clutch I! of any standard or approved type. The servo-- motor l3 and consequently the valve II are rendered responsive to the speed of the pump III, the arrangement being such that the valve II will promptly close whenever operation of the pump I0 falls below a certain predetermined speed.

The centrifugal governor I! may assume vari- 55 the position shown.

ous forms. That shown comprises a supporting shaft I9 driven by the one-way clutch l8 and having thereon a pair of axially spaced end heads 20 and 2|. Head 20 is fixed to the shaft l9 while head 2| is freely movable axially thereof toward and fromthe-head 20. The heads carry a suitable centrifugal fly-ball arrangement which in this instance comprises a pair of heavy bars 22 each connected to both heads through flexible 10 metallic strips 23. The bars 22 are also interconnected by a pair of parallel tension springs 24 disposed at opposite sides of the shaft l9, each end of each spring being connected to an end of a bar 22 throughan appropriate link bolt 25.

The springs 24 yieldably resist outward movement of the bars 22 under the centrifugal forces induced by rotation thereof with the shaft IS, in-

ward movement of the bars 22 being limited by suitable adjustable stops, such as screws 26 carried by a collar 21 on the shaft is.

The arrangement is such that during rotation of the shaft IS, the bars 22 move outwardly and, acting through the strips 23,' draw the head 2| lengthwise of the shaft [9 a distance dependent 25 upon'the rate of shaftrotation.

This axial movement of the head 2| is utilized to actuate and control the valve Hi. In this instance the valve I6 is equipped with an extended valve stem 28 that projects into the adjacent hol- 30 low end of the shaft IS. A transverse pin 28 carried by the head 2| and extending through the stem 28 provides a suitable operating connection therebetween, the shaft I9 being longitudinally slotted to accommodate the pin 23 and "to permit the same to move with the stem '28 and head 2|.

The valve I6 is a four-way valve of a well known type. It includes a longitudinally movable plunger controlled by the stem 28 and hav- 40 mg a central head 30. and spaced end heads 3| and 32. The central head 30 controls an annular channel 33 that is continuously supplied with liquid under pressure through a pipe 34. Each of the end heads 3| and 32 controls an annular channel 35, both of which communicate with an exhaust pipe 36. An annular channel 31, disposed between the heads 30 and 3|, conimunicates through a pipe 38 with one end of the servo-motor [3; while another annular channel disposed between the

heads

30 and 32 com- 00 is equipped with an actuating plunger 44 by which it may be opened in response to pressure generated by the pump [0. For this purpose the plunger 44 is shown arranged within a cylinder 45 which is exposed to the discharge pressure of the pump l through apipe 4B. The valve 42 is preferably by-passed by a connection 41 containing a suitable check valve 48 arranged to permit a free flow of liquid through the pipe 40 in an opposite direction.

The arrangement is such that when the pump I0 is at rest the valve 42 is closed and th lunger of the four-way valve It assumes the position shown, in which position the forward end of the servo-motor I3 is exposed to the pressure in the supply pipe 34 through the channels 33 and 31 and pipe 3!, and the cone valve II is held in closed position. When the pump i0 is energized gal governor ll, driven thereby, functions to shift the plunger of the valve I8 toward the left (Fig. 2) until the central head 30 passes to the left of the supply channel 33, in which position the end head It uncovers the adjacent channel 35 so as to open communication between it and the channel 31 and the end head 32 blocks the other channel 35. In this position the forward end of the servo-motor i3 is open to the discharge pipe 38 through the pipe 38 and channels 31 and ll, and the pipe 40 is open to the supply pipe 34 through the channels 39 and 33.

Although the four-way valve It has thus been operated in response to a predetermined speed of the pump ll in a manner to subject the pipe 40 to the pressure in the supply pipe 34, the'servomotor l3 does not function to open the cone valve ii until the pump 10 has generated a predetermined pressure suflicient to open the valve 42; but when this occurs, the pressure in pipe 40 is then available to promptly actuate the servomotor It in a manner to open the valve II.

The valve Ii remains open so long as the speed of the pump in remains above a predetermined minimum, but with any decrease in speed, the governor ll forces the plunger of the valve, 14 toward the position shown, and the instant that the and attains a predetermined speed, the centrifupump speed falls below that minimum the central head 30 of the valve I6 opens the supply channel 33 to the channel 37 to thereby direct fluid pressure into the pipe 38 and to thus energlue the servo-motor I3 in a direction to close the cone valve H. During this valve closing action of the servo-motor, the liquid discharged therefrom is free to flow through the pipe 40 and check valve 48 to and through the valv channels 3! and 35 to the exhaust pipe 35. It will be noted that the check valve 48 insures a free discharge of liquid from the servo-motor so as not to interfere with its valve closing action, even though the valve 42 may have closed as a result of a drop in pump pressure.

A control system has thus been provided which functions to maintain the main valve ll open only while the pump I0 is functioning normally and at a speed above a. predetermined value and by which the valve H is promptly closed whenever the pum speed falls below that value, so as to effectively block the flow in the main i2 long before a reverse flow or back surge can develop therein as a result of pump failure. Should the pump in starting fail to develop alnormal pressure, as a result of priming failure or otherwise. the control system shown will function to hold the valve ll closed, the valve 42 being provided for that purpose.

It wfll be also noted that by reason of the fact that the governor I1 is driven from the pump I 0 through a one-way clutch l8, the governor I! will come to rest or remain at rest, and consequently the valve 1 I will close or remain closed, should the pump ill at any time operate in reverse.

Various changes may be made in the embodiment of the invention hereinabove specifically described without departing from or sacrificing the advantages of the invention as defined in the appended claims.

I claim:

1. In a pumping system the combination of a conduit, a pump for supplying liquid to said con duit, a valve for controlling communication between said pump and conduit, a servo-motor alternatively operable to open and close said valve, and speed responsive ,means including a centrifugal governor driven by said pump and atomway valve actuated by said governor for rendering said servo-motor operable to open or to close said valve whereby said valve is maintained in open condition only when said pump is operating at speeds above a predetermined minimum.

2. In a pumping system the combination of a conduit, a pump for supplying liquid to said conduit, a valve for controlling communication between said pump and conduit, a servo-motor alternatively operable to open and to close said valve, a four-way valve for controlling said servomotor, and a centrifugal governor driven by said pump and mechanically connected to said last named valve to control the latter.

3. In a pumping system the combination of a conduit, a pump for supplying liquid to said conduit, a valve for controlling communication between said pump and conduit, a servo-motor alternatively operable to open and to close said valve, a four-way valve for controlling said servomotor, and a centrifugal governor driven by said pump and operable on said last named valve to actuate the same.

4. In a pumping system the combination of a conduit, a pump for supplying liquid thereto, a

valve for controlling communication between said.

pump and conduit, a servo-motor alternatively operable to open and to close said valve, means including a centrifugal governor for controlling said servo-motor, and a one-way clutch through which said governor is driven by said pump.

5. In a pumping system the combination of a conduit, a pump for supplying liquid to said conduit, a valve for controlling communication between said pump and conduit, means including a centrifugal governor responsive to the speed of said pump for opening said valve at a predetermined pump speed and for closing said valve at pump speeds below said predetermined speed, and pressure responsive means for preventing opening of said valve when pump pressures are below a predetermined minimum.

HARRISON B. HOEFER.

REFERENCES CITED The following references are of record in the die of this patent:

UNITED STATES PATENTS Number Name Date 868,541 Forester Oct. 15, 1907 1,123,876 Hiddleson Jan. 5, 1915 1,229,470 Joleen June 12, 1917 1,980,374 Bradshaw Nov. 13, 1934 2,067,479 Dahlstrand et al. Jan. 12, 1937