US2573297A - Pumping system - Google Patents

Description

Patented Oct. 30, 1951 Edward B. Atkinson, Steubenville, Ohio, assigner to National Steel Corporation, a. .corporation of Delaware Applieauonmarchis, 194s, serial No. l15,593

' s claims. (ci. 10a-.40)

The present invention relates to improvements in pumping systems for pumping liquid from a lower to a higher elevation, and is primarily concerned with preventing .damage to the system and its component parts by surging liquid.

In pumping systems for pumping, for exampleJ Water from a source ,at a relatively low level up to a plant or storage facilities located `on a Ahigh bank or bluff, a relatively high head yor pressure is developed. If the pump is stopped .therarn effect of the back or downwardlysurging water may cause a damage to the pump and the equip` ment. It is common practice, in such pumping systems, to use an Aelectrically driven vcentrifugal pump and when the pump is stopped as a lresult of power failure or other cause, the water will flow downwardly through the system and operate the pump in reverse. Operating the pump in reverse at high vspeeds may cause damage to the pump and if the power comes back on with .the pump in reverse, the pump may be damaged by the sudden change in direction vof operation.

Accordingly, the object of the present invention is to provide an improved pumping system for pumping liquid from a 'lower to a higher level so constructed and arranged that no damage will result when the pump is stopped.

Another object of the present invention is to provide an improved pumping system for pumping liquid from a lower toa higher level, ,so constructed and arranged as to prevent harmful flow of liquid downwardly through the --system when the pump is stopped.

It is also an object of the present invention to provide an improved pumping system for `pumping liquid from a lower to a higher level including control means automatically operable to restrict downward ow of liquid through the system upon the stopping of `the pump.

It is also an object of the present invention to provide an improved pumping system for pumping liquid Vfrom -a lower to a higher level Aincluding control means automatically opera-ble to restrict downward flow of liquid through the Ysystem upon the stopping of the pump.

In accordance with `a preferred Yembodiment of the present invention, a pumping system which includes a conduit extending lfrom -a lower to a higher elevation is provided with Aa pump, a normally open valve lon the inlet or outlet side of the pump, and either mechanical or electrical control means automatically operable 'to close the valve when `the pump stops as -a result of power failure or other cause. lThe valve is in operating normally Ato allow substantially unrestricted -flow of liquid upwardly through the conduit. The valve is so constructed andarranged that when it is in a relatively closed -posi tion the valve is only partially closed so as to allow restricted flow of liquid through the conduit. Thus, when the pump stops, the control means automatically closes the valve to the partially closed position so that the liquid lflows downwardly through the system at a greatly reduced rate of flow. The backward flow is maintained at a sufliciently low rate to prevent damage to the pump when the pump `is again started. As the valve is .only partially closed, the head .orzback pressure is gradually Adissipated and the backsurge Aof the liquid is cushioned. If no valves were provided the pump and possibly other portions of the system Would Ybe damaged. Ii' the valves were completely closed the ram effect of the backsurging liquid would ydamage the pumping system.

These and other objects and advantages will become more readily -apparent from lthe following detailed description, taken f-rom the accompanying drawings, in which:

Figure 1 is a schematic representation of a pumping system embodying the principles of the present invention;

Figure 2 is an `enlarged View, partially in section, of a valve embodying the principles of the present invention and being part of the pumping system of Figure l; and

Figure 3 is a `diagrammatic representation of a wiring diagram .and control means for closing the valve .of Figure 2.

Referring more particularly to Figure 1 Vof the drawings, the pumping system includes a `long conduit I0 terminating at its `lower end in a pipe H which extends below vthe surface .of ka body of ysupply water indicated at l2. The body of supply water :l2 may be a river, pond, tank or other source located at :a relatively lowlevel. The conduit .I ll extends up a relatively steep grade or embankment 1.3 to a tank indicated at I4. The tank I4, which is at the upper outlet end .of thc conduit :l 0, may be a tank of the water system of a mill or may be any other suitable place of .disposal which is at a vhigher elevation than the source .at I2. The pumping system `includes a centrifugal pump t6 operated -by a motor ll Figure 3, for pumping the liquid from the source :1.2 to the :tank 14.

A power actuated valve LIB is provided in the conduit |10 for rcontrolling -the flow Iof liquid the relatively open posi-tion when the #pump through the system. Thispower actuatedvalve f Y l. 3

I8 is shown more fully in Figure 2. The valve means I8 includes a valve casing |9, having a circular substantially disc-like, relatively thinner valve member 20 extending across the passage 2| in casing I9. The passage 2| is in communication with other portions of the passage through the conduit l0. The valve member 2|) is mounted on and connected to a shaft 22 rotatably mounted in the casing for rotation about its axis.

The axis of rotation of shaft 22 and valve member 20 extends transversely of passage 2| and parallel both to a diameter of the circular passage 2| and a diameter of the circular valve member 20. Glands 23 and 24 arev provided for sealing the valve and preventing leakage of liquid. The shaft 22 extends outside of the casing I9 and also is suitably rotatably mounted in the framework 25. Motor 26 is connectedthrough shaft 21 and suitable gearing inside the gear cover 28 to the shaft 22 so that as the motor 26 is rotated the shaft 22 is turned to open or close the valve. A suitable, releasable brake 3i! is provided for automatically engaging drum 3| on shaft 22 to hold the valve member 20 in a fixed open or closed position. The brake 3D may be of any suitable type and preferably is automatically released upon energization of motor 26to permit the motor to turn the shaft 221 and valve member 26 as desired. The motor 2B may be reversible or may rotate in the same direction to move the valve member 20 to the relatively open and closed positions.

The circular valve member 2|! is shown in Figure 2 in the closed position. The thickness of member 20 is considerably less than its diameter so that when the member is turned 90 from the position shown in Figure 2 to the position indicated in Figure 3, the Valve is in the open position and permits substantially unrestricted flow of liquid through the conduit l0. Member 20 has a smaller diameter than the passage 2| so that when the valve member is in the relatively closed position there is a relatively small space 32 between the edge of member 20 and passage 2| and liquid can flow through this space at a greatly reduced rate of flow.

Referring more particularly to Figure 3, the pump motor IT is connected by wires 33 and 34 to wires 35 and 36 which are connected to a suitable source, not shown, of electric current and these wires constitute a simplified circuit for supplying electric current to motor ll. This circuit may include other control means and switches, if desirable. Control means for closing valve |8 upon de-energization of motor l! is also shown in Figure 3.- As diagrammatically shown, the valve motor 26 is connected to a limit switch 33', brake drum 3| and valve member 2|) so that these elements rotate in unison. The motor 26 is connected through a wire 34' to one side of a battery 35'. Motor 26 is connected through wire 36', normally closed switch 31, Wire 38, contacts 39 and 40, and wire 4| to the other side of'battery 35. With switch 31 closed and switch contacts 39 and 46 closed the motor 26 is energized to rotate the motor in a counterclockwise direction. As the motor rotates, it rotates limit switch 33' and when limit switch 33 has turned 90 degrees, the projection 42 engages switch 3? to open the switch and de-energize the motor 26. switch 33' is so constructed and arranged that switch 31 is opened when valve member 20 is in the closed position shown in Figure 2. A solenoid 44 is connected through wire 45 to wire 34' and through Wire 46 to wire 36 so thatsolenpid 44 VLimit 4 is energized and de-energized simultaneously with motor 26. When solenoid 44 is energized it disengages the brake 30 from brake drum 3|, so that the motor 26 and the valve member 20 can turn. With solenoid 44 de-energized the brake 30 engages drum 3| to hold the valve member 2|] in a fixed position.

Asolenoidf48 is'connected through wires 49 and 50 to wires36 and 35 so that when motor ll is energized or de-energized, solenoid 48 is simultaneously energized or de-energized. Solenoid 48 Y' operated substantially continuously so that switch 5|-and valve I8 are normally open. When pump motor Il is de-energized as a result of power failure, or other cause, current no longer iloWs through wires 35 and 36 and solenoid 48 is cle-energized. With solenoid 48 de-energized, switch 5| closes and solenoid 44 and motor 26 are energized by the battery 35', or other source of power. Energization of solenoid 44 releases brake 35 from drum 3| and the energized motor 26 closes valve I8. When the valve member 20 has been turned the projection 42 engages switch 3l and opens this switch to de-energize motor 26 and solenoid 44. The brake 38 engages drum 3| and holds the valve member in this relatively closed position.

Any suitable control means may be provided for automatically or manually reopening valve |8 when motor is again energized. Such control means forms no part of the present invention.

When valve |8 is in the relatively closed position the pump motor is not energized, liquid ows downwardly through the space 32 and the pump |6 to operate they pump in reverse at a relatively slow speed. The size of space 32 may vary depending upon various factors but is small enough so that the pump i6 will not be operated in reverse at a suiciently high speed to cause damage to the pump, especially when the motor is again energized to operate the pump in the forwardvdirection. In one particular installation where water is pumped up 200 feet, it has been found that a 1A; inch space around valve member 26 permits sufficient water to iiow downwardly to operate the pump |6 in reverse at about 25 revolutions per minute, and at this speed the pump is not damaged when the motor l1 is suddenly energized to rotate in the forward direction. A smaller clearance of, for example, about 1/8 inch can be used.

The motor 26 takes time to close valve I8 and in the installation mentioned above, the motor requires about i-lve seconds to close valve |8. When the motor is de-energized, the upwardly flow liquid changes direction and surges downwardly through the conduit. Closing the valve gradually eliminates any objectionable ram effect by the back-surging liquid to prevent damage to the apparatus. As the valve member 26 is being turned to the closed position, water flows downwardly through the valve and this aids in cushioning the back surge of the liquid in the conduit vvwhen motor stops. As liquid slowly leaks past the valve, the head of liquid is further dissipated which reduces the torque required to start the pump |6 in the forward direction and this tends k15 to increasethelife of the apparatus.

I claim:

1. In a liquid pumping system, a conduit extending from a lower inlet end to an outlet end at a higher elevation, pump means arranged to pump liquid upwardly through the conduit between the pump and the outlet end, valve means associated with the conduit for controlling the flow of liquid through the conduit, said valve means being operable to an open position in which the valve means permits substantially unrestricted flow of liquid through the conduit and being operable to a partially closed position in which valve means permits restricted flow of liquid through the conduit, and control means associated with the pump means and the valve means constructed and arranged to operate the valve to said partially closed position only upon stoppage of the pump means, whereby the valve means permits restricted iiow of liquid downwardly through the conduit when the pump stops.

2. In a liquid pumping system, a conduit extending from a lower inlet end to an outlet end at a higher elevation, pump means arranged to pump liquid through the conduit, normally open valve means between the pump means and the outlet end having a valve passage and a movable valve member in the passage for controlling the flow of liquid through the conduit, said valve member being smaller than the valve passage when in the most nearly closed position, and control means associated with the pump means and the valve means operable to effect movement of said valve member from the normally open position to said most nearly closed position only upon stoppage of the pump means whereby the valve means restricts flow of liquid downwardly through the conduit when the pump means stops.

3. In a liquid pumping system, a conduit eX- tending from a lower inlet end to an outlet end at a higher elevation, a pump arranged to pump liquid through the conduit, an electric motor for operating the pump, a normally open, partially closeable valve associated with said conduit between the pump and the outlet end for controlling the iiow of liquid through the conduit, power actuated means for operating the valve from the normally open to the partially closed position, and electrically operated control means for the power-actuated means operable only upon de-energization of the pump motor to cause said power actuated means to partially close said valve whereby restricted flow of liquid downwardly through the conduit is permitted upon de-energization of the pump motor.

4. In a liquid pumping system, a conduit eX- tending from a lower inlet end to an outlet end at a higher elevation, a pump for pumping liquid through the conduit, an electric motor for operating the pump, normally open valve means between the pump and the outlet end for controlling the flow of liquid through the conduit including a valve casing having a circular passage extending therethrough and including a circular, relatively thinner valve member in said passage supported for rotation about an axis extending parallel to a diameter of the valve passage and to a diameter of the valve member for movement to relatively open and closed positions, means for rotating the valve member about said axis from the relatively open to the relatively closed position, and control means operable only upon de-energization of said electric motor to actuate the rotating means to move the valve member to the closed position, said valve member having a diameter less than said passage so that there is a clearance space between the periphery of the valve member and the passage wall whereby the valve member permits restricted iiow downwardly through the conduit when in the closed position.

5. In a liquid pumping system, a conduit extending from a lower inlet end to an outlet end at a higher elevation, a pump arranged to pump liquid through the conduit, an electric motor for operating the pump, valvemeans between the pump and the outlet end for controlling the flow of liquid through the conduit including a valve passage, a valve member in the valve passage movable from a substantially open to a now-restricting position, an electric valve motor for moving the valve member to the now-restricting position, said valve member being smaller than the valve passage when in the closed position, and an electrical circuit for supplying electric current to the valve motor, said circuit including electrically controlled switch means closeable only upon de-energization of the pump motor, whereby the valve member is moved to the closed position to restrict the flow of liquid downwardly through the conduit and the system when the pump motor is de-energized.

6. In a liquid pumping system, a conduit extending from a lower inlet end. to an outlet end at a higher elevation, a pump arranged to pump liquid through the conduit, an electric motor for operating the pump, valve means between the pump and the outlet end for controlling the flow of liquid through the conduit including a valve passage, a valve member in the valve passage movable from an open to a flow-restricting position, and an electric valve motor for moving the valve member to the now-restricting position, said valve member being smaller than the valve passage, whereby said valve member when in the closed position permits restricted flow through the valve passage and the conduit passage, an electrical circuit for supplying electric current to the pump motor, an electrical circuit including a switch for supplying electric current to the Valve motor, and electrically controlled means electrically connected to the pump motor circuit for holding the switch in the open position only when current is flowing to the pump motor so that the valve motor is energized to move the valve member to the flow-restricting position to restrict the flow of liquid downwardly through the conduit and the system only upon de-energizaticn of the pump motor.

EDWARD B. ATKINSON.

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

UNITED STATES PATENTS Number Name Date 1,421,409 Conrader July 4, 1922 2,081,860 Quick Mar. 25, 1937 2,174,153 Dorer Sept. 26, 1939 2,219,359 Goit et al. Oct. 29, 1940 2,220,327 Goit et a1 NOV. 5, 1940 2,436,442 Mauch Feb. 24, 1948

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