US2730955A - Pump drive control - Google Patents

Description

Jan. 17,1956 B. SHARE- 2,730,955

PUMP DRIVE CONTROL 2 Sheets-Sheet 1 Filed Sept. 10, 1952 Z INVENTgR.

jo INTO/QUE) Jan. 17, 1956 SHARE 2,730,955

PUMP DRIVE CONTROL Filed Sept. 10, 1952 2 Sheets-Sheet 2 Z IN VEN TOR.

A ff /z/vE) United States Patent PUMP DRIVE CONTROL Barnett Share, Jamaica Estates, N. Y.

Application September 10, 1952, Serial No. 308,857

8 Claims. (Cl. 103-113) This invention relates to controls for pump drives wherein a priming pump is driven from a main pump and, more particularly, to an automatic control, responsive to liquid pressure at the main pump outlet, to control the driving connection of the priming pump from the main pump. This application is a continuation in part of my copending application Ser. No. 287,713,. filed May 24, 1952, and now Patent No. 2,675,762, issued April 20, 1954.

Centrifugal pumps are frequently used for water extraction purposes, for example, with a series of driven well-points designed to maintain the water level of an area, such as an excavation, below a predetermined level. In initiating the pumping action, it is necessary to prime the centrifugal pump until a predetermined liquid pressure is developed at its outlet.

For this purpose, an auxiliary or priming pump is connected to the centrifugal pump to evacuate air therefrom and thus provide for flow of water through the centrifugal pump. Most conveniently, these priming pumps are driven from the centrifugal pump so that the priming pump is started whenever the centrifugal pump is started.

While the priming pump can be continually operated all during the time the centrifugal pump is operated, this is wasteful of power. Hence, many arrangements have been devised for disconnecting the drive of the priming pump after the centrifugal pump has begun to deliver water from its outlet.

These prior disconnecting arrangements have included both manually operable devices and automatically operable devices. Manually operable devices are dependent upon the human element and thus reliability of disconnection of the priming pump at the proper time can be assured. The automatic devices hitherto proposed have been unduly complicated or expensive, or have not been reliable.

In accordance with the present invention, a simple, inexpensive, and fully automatic priming pump drive control is provided which is effective not only to disconnect the priming pump drive when priming of the centrifugal pump is no longer needed, but also to reconnect the priming pump drive automatically whenever further priming is needed. To assure reliability of operation, the actuation of the drive control is made directly dependent upon the liquid pressure at the centrifugal pump outlet, this pres sure being a direct indication of whether or not priming is needed.

More specifically, the priming pump is mounted for movement toward and away from the main pump and driven from the latter by driving means which must be maintained under tension to be effective.

The priming pump is swingably mounted in such manner that it is biased by gravity away from the main pump. Means are provided, operating directly in response to liquid pressure at the main pump outlet, to swing the priming pump, against the gravity bias, toward the main pump to render the driving means ineffective. Thus,

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whenever the liquid pressure at the main pump outlet is at or above a pre-set value, the priming pump drive is rendered ineffective, but the drive is immediately and automatically made effective whenever such outlet pressure drops below such pre-set value. Other means, responsive to liquid output from the main pump, interrupt the priming connection to the priming pump When the main pump is delivering liquid.

For an understanding of the invention principles, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing. In the drawing:

Fig. 1 is a somewhat schematic elevation view, partly in section, illustrating the invention drive control in the priming position;

Fig. 2 is a similar view showing the control with the priming pump drive ineffective; and

Fig. 3 is a view similar to Fig. 1, showing an alternative embodiment of the drive control.

Referring to Fig. l, a main centrifugal pump 10 is shown as supported on a suitable base 11. Pump 10, in the usual manner, has an axial inlet (not shown) and an outlet 12 connected to a chamber 13. A spring biased valve 15 closes the connection between outlet 12 and chamber 13 except at such times as the liquid pressure at the outlet equals or exceeds a pre-set value. When the pressure attains this value, valve 15 is lifted so that liquid flows from outlet 12 into chamber 13 and out through discharge pipe 14.

in communication with the interior of pump it) and thus with outlet 12, is a float chamber 16. A float valve 2b is pivoted at 17 on the side wall of the chamber 20, and carries a float 18. When the liquid in chamber 16 reaches a pre-set level, valve 2% is swung to close an opening 21 to a priming line 22 leading to the inlet 23 of a relatively small priming or auxiliary pump 25 having a discharge pipe 29.

Priming pump 25 is supported on a platform 24 to one end of which is secured a downwardly extending support 27 pivotally mounted in a bearing 28 on platform 11. The pump is mounted in spaced relation to support 27 so that the pump weight biases platform 2d counter-clockwise as viewed in the drawing figures.

To permit movement of pump 25 relative to pump 10, priming line 22 is made partially or completely flexible. Pump 25 is driven from pump ill by a belt 31 trained over a pulley 32, on the drive shaft of pump ill, and a pulley 33 on the drive shaft of pump 25. A guard 34- partially surrounds pulley 32, and a guard 36 surrounds pulley 33.

The drive control includes the valve 15 which has a stem 41 sliding in a guide 42 extending from cap 43 of chamber 13. A flexible cable, generally indicated at 45, has its casing 46 fastened to and sealed into guide 42, the cable being clamped to cap 43 by clamp i l. Adjacent its other end, cable 45 is secured firmly to platform ill by a clamp 47. The movable core 5d of cable 45 is soldered or otherwise secured, at one end, into valve stem il, so that core 50 moves, relative to casing 4d, whenever valve 15 moves. The other end of core 56} engages the underside of the free end of platform 24, being held thereto by a clamp 48 secured by a bolt and nut arrangement $9.

in the off or starting conditions of pump iii, the components occupy the positions shown in Fig. 1. Valve 15 is closed, so that cable core dd has its free end drawn into casing 46 allowing platform 24 to be biased counterclockwise by the weight of pump 25.

When pump M is started, pump 25 is driven to draw the air from pump ill and its connections through priming line 22, discharging this air through pipe 29. As pump 10 commences to deliver liquid, the liquid level in cham ber 16 rises sothat float valve 20 eventually closes priming line 22.

Meanwhile, fluid pressure builds up in outlet 12, and reaches the pre-set value at "which valve 15 lifts so that pump discharges through pipe 14. As valve is lifted, core 50 of flexible cable '45 is moved to swing platform 24 clockwise. This moves pump 25 clockwise to remove the tension from belt 31, thus rendering the priming pump drive ineifective. Guardsf34, 36 prevent displacement of belt 31.

Should the outlet pressure drop sufficiently to allow valve 15 to be closed by its spring, the valve pulls cable core 50 into chamber 13, allowing the weight of pump 25 to swing support 24 counter-clockwise to reestablish the driving connection between pumps 19 and 25.

- Fig. 3 shows an alternative embodiment in which flexi- -ble cable '45 is replaced by a hydraulic system. In this case, a flexible conduitr55 has one end fastened in and fluid-tightly sealed to guide 42. The other end of conduit 55 is connected to a cylinder 56 mounted beneath the free end of platform 24 and having a piston 57 engaging the underside of the platform. Conduit 55, valve guide 42,

and cylinder 56 are filled with hydraulic pressure fluid so that, as valve '15 is lifted, valve stem 41 acts as a piston to force hydraulic fluid into conduit 55. This forces piston 57 outwardly of cylinder 56 to swing platform 24 clockwise to disconnect the pump drive. When valve 15 closes, the outward movement of valve stem 41 relative to guide 42 allows hydraulic fluid to flow out of cylinder 56 into conduit 55. The weight of pump 25 causes platform 24 to push piston 57 inwardly. The movement of platform 24 reestablishes the pump driving connections.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the invention principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A pump drive control comprising, in combination, a main pump for displacing liquid, and having an outlet for liquid under pressure and a liquid inlet; a priming pump having a priming connection to said main pump; a valve normally biased to close said outlet and having a stem on its outer face slidable in a guide, said valve being operable, upon attainment of a preset outlet pressure of 7 said main pump, to open and move said stem through said guide; a tension driving means interconnecting said pumps for driving said priming pump from said main pump; means mounting said priming pump for movement relative to said main pump; gravity influenced means biasing said priming pump away from said main pump to maintain driving tension on said driving means; and mechanism,

establishing an operative connection between said valve stem and said pump mounting means, operable, upon attainment of a pre-set outlet pressure of said main pump, to move said priming pump toward said main pump to remove the driving tension from said driving means.

2. A pump drive control comprising, in combination, a main pump for displacing liquid, and having an outlet for liquid under pressure and a liquid inlet; a priming pump having a priming connection to said main pump; a valve normally biased to close said outlet and having a stem on its outer face slidable in a guide, said valve being operable, upon attainment of a preset outlet pressure of said main pump, to open and move said stem through said guide; a tension driving means inter-connecting said pumps for driving said priming pump from said main pump; means mounting said priming pump for movement relative to said main pump; gravity influenced means biasing said priming pump away from said main pump to maintain driving tension on said driving means; mechanism, establishing an operative connection between said valve stem and said pump mounting means, operable,

upon attainment-of a-pre-set outlet pressure of said main pump, to move said priming pump toward said main pump to remove the driving tension from said driving means; and means operable responsive to delivery of liquid from said main pump to interrupt said priming connection.

3. A pump drive control comprising, in combination, a main pump for displacing liquid, and having an outlet for liquid under pressure and a liquid inlet; a priming pump having a priming connection to said main pump; a tension driving means inter-connecting said pumps for driving said priming pump from said main pump; a platform pivotally supported at its end nearest said main pump, said priming pump being mounted on said platform between its supported and free ends and biasing said platform to swing its free end away from said main pump to maintain tension on said driving means; a valve biased to close said outlet until the main pump delivery pressure attains a pre-set value; and a force-transmitting connection between said valve and the free end of said platform and operable,.when said valve opens responsive to said preset delivery pressure value, to swing said platform and priming pump toward the main pump to remove the driving tension from said driving means.

4. A pump drive control, comprising, in combination, a main pump for displacing liquid, and having an outlet for liquid under pressure and a liquid inlet; a priming pump having a priming connection to said main pump; a tension driving means inter-connecting said pumps for driving said priming pump from said main pump; a platform pivotally supported at its end nearest said main pump; said priming pump being mounted on said platform between its supported and free ends and biasing said platform to swing its free end away from said main pump to maintain tension on said driving means; a valve biased to close said outlet until the main pump delivery pressure attains a pre-set value; and a flexible cable extending between said valve and the free end of said platform and operable, when said valve opens responsive to said pre-set delivery pressure value, to swing said platform and priming pump toward the main pump to remove the driving tension from said driving means.

5. A pump drive control comprising, in combination, a main pump for displacing liquid, and having an outlet for liquid under pressure and a liquid inlet; a priming pump having a priming connection to said main pump; a tension driving means inter-connecting said pumps for driving said priming pump from said main pump; a platform pivotally supported at its end nearest said main pump; said priming pump being mounted on said platform between its supported and free ends and biasing said platform to swing its free end away from said main pump to maintain tension on said driving means; a valve biased to close said outlet until the main pump delivery pressure attains a pro-set value; and a flexible cable extending between said valve and the underside of the free end of said platform and operable, when said valve opens responsive to said said pre-set delivery pressure value, to swing said platform and priming pump toward the main pump to remove the driving tension from said driving means.

6. A pump drive control comprising, in combination, a main pump for displacing liquid, and having an outlet for liquid under pressure and a. liquid inlet; a priming pump having a priming connection to said main pump; a tension driving means inter-connecting said pumps for driving said priming pump from said main pump; a platform pivotally supported at its end nearest said main pump, said priming pump being mounted on said platform between its supported and free ends and biasing said platform to swing its free end away from said main pump to maintain tension on said driving means; a valve biased to close said outlet until the main pump delivery pressure attains a pre-set value; and a hydraulic pressure system extending between said'valve and the free end of said platform and operable, when said valve opens responsive to said pre-set delivery pressure value, to swing said platform and priming pump toward the main pump to remove the driving tension from said driving means.

7. A pump drive control comprising; in combination, a main pump for displacing liquid, and having an outlet for liquid under pressure and a liquid inlet; a priming pump having a priming connection to said main pump; a tension driving means inter-connecting said pumps for driving said priming pump from said main pump; a platform pivotally supported at its end nearest said main pump; said priming pump being mounted on said platform between its supported and free ends and biasing said platform to swing its free end away from said main pump to maintain tension on said driving means; a valve biased to close said outlet until the main pump delivery pressure attains a pre-set value; and a hydraulic pressure system extending between said valve and the underside of the free end of said platform and operable, when said valve opens responsive to said pre-set delivery pressure value, to swing said platform and priming pump toward the main pump to remove the driving tension from said driving means.

8. A pump drive control comprising, in combination, a main pump for displacing liquid, and having an outlet for liquid under pressure and a liquid inlet; a priming pump having a priming connection to said main pump, a tension driving means inter-connecting said pumps for driving said priming pump from said main pump; a platform pivotally supported at its end nearest said main pump; saidpriming pump being mounted on said platform between its supported and free ends and biasing said platform to swing its free end away from said main pump to maintain tension on said driving means; a valve biased to close said outlet until the main pump delivery pressure attains a pre-set value; said valve having a stern engaged in a tubular stem guide; a cylinder having a piston engaged with the underside of the free end of said platform; and a hydraulic pressure line inter-connecting said valve stem guide and said cylinder; whereby, when said valve opens responsive to said pre-set delivery pressure value, said piston will be projected to swing said platform and priming pump toward the main pump to remove the driving tension from said driving means.

References Cited in the file of this patent UNITED STATES PATENTS 1,107,533 Lorenz Aug. 18, 1914 1,949,428 McGee Mar. 6. 1934 2,675,762 Share Apr. 20, 1954 FOREIGN PATENTS 253,205 Great Britain June 14, 1926 396,218 Germany July 4, 1922 401,149 Germany Jan. 14, 1938

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