US2238597A - Pumping apparatus - Google Patents

Description

April 15, 1941. A. 0. PAGE 2,238,597

PUMPING APPARATUS Filed Aug. 24, 1959 2 S heefss-Sheet 1 April 15, 1941. A. c. PAGE 2,238,597

PUMPING APPARATUS Filed Aug. 24, 1959 2 sheets-sheet 2 0 m; INVENTOR. 79 6/ JWefdJ/idf/fif faye BY I ATTO Patented Apr. 15, 194

PUMPING APPARATUS Alired Charles Page, Detroit, mm. alllfllol' to Chicago Pump Oompany, Chicago, 111.,

poration of Illinois Application August 24, 1939, sci-nu No. mp4s p 12 Claims.

This invention relates to pumping apparatus and particularlyto that type utilizing pumps to handle sewage or trade wastes containing suspended solids such as rags, waste or stringy materlals and other solids which may clog the impeller of the pump.

One object of the invention is to provide means to cause a reversal of how through parts oi the system to flush certain strainers in which the solids are collected when thepump is operating.

Another object is to provide auxiliary control means whereby when the pump is operating for a period or time, certain valve mechanism of the control means will be reversed to cause the stream of water containing the suspended solids to change its flow from one strainer to the other and for a reverse flow to occur through the strainer which first received the flow for a period of time.

Another object is to provide a motor driven valve mechanism to reverse the flow through the strainers, together with an electric circuit whereby when the pump motor is operating normally, for periods of less than certain predetermined ones, for example less than ten minutes, the valve motor will remain idle, but when the pump motor stops, the valve motor will operate and rotate the valve to direct the flow through a reversed direction.

With these and other objects and advantages in view, this invention consists in the several novel features hereinafter fully set forth and claimed;

- One embodiment of the invention is clearly illustrated in the drawings accompanying this specification, in which:

Fig. l is a vertical cross-section through a pump pit showing a wet well to collect the liquid and a dry pit to receive the pump and associated parts, the pumping apparatus being shown in side elevation.

Fig. 2 is an end elevation of parts of the pump, valve and piping shown in Fig. l, but showing the valve mechanism in section to show the interior construction.

Fig. 3 is an elevation partly in section of a worm and worm wheel for actuating the valve.

Fig. 4 is a central longitudinal sectional view through the valve and worm wheel.

Pig. 5 is a central vertical section through one 01' the strainers, and

Fig. 6 is a diagrammatic view of the wiring and control apparatus.

Referring to the drawings, which are merely illustrative of one form of the invention, in indicates a sewer or waste pipe from an industrial plant and this pipe is provided with a shut-oi! valve ii of the gate valve or shear gate type as may be desired. The reference character I! designates a wet well into which the liquid from. the

pipe ll empties.

The wet well is formed by a retaining wall II, a separating wall I and bottom I. A dry pit formed of the retaining wall it, bottom l1 and the separating wall I4 is located adiacent the wet well and this dry pit contains the pump, piping, strainers and valve mechanism forming the subject matter of this invention.

The separating wall it is provided with two wall pipes II which are arranged side by side in spaced relation (see Fig. 2) and in the same plane. In Fig. l, the second wall pipe I! is located directly behind that-shown. These wall pipes receive extension pipes I! to which check valves 20 are connected through flexible flttings 2|. U bends 22 are connected to the check valves and have their upper ends connected to T fittings 23. A base member of a strainer H (see Fig. 5) is connected to the upright branch 0! each 1' ntting 23, and this base member is provided with an annular groove 25 machined in the inside wall to receive a gasket 26 that impinges-against the shell 21 oi the strainer housing. The base member is also machined to receive the flange II of a perforated or otherwise formed. strainer 29.

A valve 3| having a housing "a (see Figs. 1, 2

21 are attached, and said valve housing is also provided with two vertically disposed hubs 32 and 33. The upwardly directed hub 32 flares outward and terminates in a flange 34 to which the volute chamber of pump it is connected. This connection is to the suction side 0! the pump II, and the discharge from the volute chamber terminates in the elbow I which is directed downwardly to receive the single connecting discharge pipe 31. A U-bend 38 connects the discharge pipe 31 with the flanged hub 38 that extends downwardly from the valve housing "a. A valve plug 38 rotatably mounted in the valve housing 30a is provided with two ports 40, 4|, and is arranged in one position to have the port 40 connect the strainer housing shell 21 through the flanged hub SI of the piping on fA" side of the apparatus, with the suction side of the pump, while port 4| connects the discharge from the pump through the hub ll to the strainer housing shell 21 of piping on B side of the apparatus. Rotation of the valve plug through reverses the flow through the strainers.

The straight through flanges of the two T's 23 are connected through adapters and flexible ilttings and check valves 42 to elbows 43 that lead to a T fitting II, the upright branch of which connects with a common discharge pipe 45,

The pump volute casing is connected to the cover plate 48 01' the pump and this cover plate is attached to the hanger pipe 4'! which has its upper end attached to the floor plate 48 upon which the motor pedestal 49 is mounted. An electric motor 56 is mounted upon the motor pedestal and drives the pump through the shaft 56a. The pump construction is of the typical centrifugal type having an impeller mounted within the volute chamber, and the extension shaft 56a rises through the hanger pipe and intermediate bearings to the place where it is connected through a coupling to the motor shaft, as is customary.

The valve plug 39 is mounted upon a shaft (see Fig. 4) which has a bearing 52 in the rear wall of the valve housing 36a and a forward bearing in a removable cover plate 53 which may be bolted to the flange of the valve housing 36a. A stuffing box 54 is provided in this cover plate and a gland 55 may be tightened when it is desired to take up on the packing to prevent leakage around the shaft. A worm wheel 56 is mounted upon the shaft 5| and is enclosed in a housing 51 so that lubricant may be supplied to the gear and to prevent drippings and other harmful agents from damaging the gearing. A worm 58 meshes with this worm wheel 56 and this worm is carried by a vertical shaft 59 which is journaled in bearings carried by the worm gear housing 51.

The vertical shaft 59 extends upwardly to the coupling 66 (see Fig. 6) and is connected to the motor shaft 6I of a valve motor 62. The motor 62 is mounted upon a housing 63 and this housing encloses a second worm wheel 64 which is mounted upon a cross shaft 65 journaled in bearings carried by the housing 63. A worm 66 carried by the vertical shaft 59 meshes with the worm wheel 64 and the ratio of the worm 66 and worm wheel 64 to the worm 58 and worm wheel 56 is four to one. That is, while worm wheel 64 is making one revolution, worm wheel 56 is making one quarter revolution.

A roller 61 is mounted upon the worm wheel 64 and in certain position of the worm wheel this roller engages an arm 66 of a trip to swing a bracket 69 and thereby tilts a circuit breaker to stop the operation of valve motor 62 as will be hereinafter described.

A float guide pipe 16 is located in the wet well and may be suspended from the basin cover II. This guide pipe is open at the top so as not to entrap any air within the pipe which might prevent free rising and falling of the liquid level within the pipe. A float I2 is slidably mounted upon a float rod 13, and adjustable buttons I4 and 15 are carried by this float rod so that the desired range of float movement may be had with respect to the float rod. A smaller pipe I6 serves to guide the float rod in its up and down movements and this pipe is attached to the under side of a. floor plate I1 upon which a standard I8 is mounted. A lever I9 is carried by this standard and has its free end connected to the float rod I3 by links 86 and a clevis 8|. The lever 19 carries a bracket 82 in which two circuit breakers or contactors 83 and 84 are mounted. A rod 86 extends from the hub of the lever 19 and carries a counter weight 86a which may be shifted as is necessary to balance the weight of the pendant float rod.

As liquid accumulates in the wet well, the level therein rises and the float I2 rises on the float rod 13 until the float ontacts the button I4 on the float rod. Then, continued upward movement of the float raises the float rod until the lever I9 has been swung to tilt the contactors 83 and 84 to the opposite position of that shown in Fig. 1, thereby closing the starter circuit for the pump motor 56. When this happens, the pump motor 56 starts and the pump draws liquid from the wet well through the piping and strainer that then leads through the valve 36 to the suction side of the pump, and discharges it through the other strainer, and finally through the discharge pipe 45 up to and through the elbow at the top thereof and the piping ultimately connected thereto.

By referring more specifically to Fig. 6, the electrical equipment and sequence of operations may be more fully understood. When the float rod I3 rises, it swings lever I9 and tilts contactors 83 and 84 to a position opposite to that shown in Fig, 6. Preferably the contactors are of the mercury switch type. When contactor 84 is swung over, the mercury flows to the other end and closes the circuit through the terminals therein. When it is desired to operate certain members of the electrical equipment at a lower voltage than that supplied through the line 85 a transformer is used for such members of the electrical equipment. Then, current from the main line 85 flows through the main line switch S and to a starter panel 81 where lines from two of the leads run to the primary winding 86 of the transformer. The secondary winding 89 of the transformer feeds a circuit through line 96 to a tap which leads to solenoid 9I and then through thermal overload circuit breakers 92, and then to one of the terminals of contactor 84. From the other terminal of contactor 84, the circuit leads back to wire 93 which returns to the secondary of the transformer. When this circuit is completed, the solenoid 9| actuatesits rocker arm and closes the contactors 94 of the starter, thereby closing the motor circuit and the motor 56 starts operating, thereby driving the pump. When the level of the water in the wet 'well falls, the float 12 drops and as it contacts the button I5, it causes the float rod to lower and continue until the switch lever 19 is swung to the position shown in Fig. 6, at which time contactor 84 tilts The electrical equipment just described comprises one means for starting and stopping the pump motor, which is responsive to liquid level changes in the wet well. Means are provided to start and stop the valve motor after the pump motor has stopped. One means will now be described:

While contactor 84 is tilted to open the circuit through it, contactor 83 is tilted to close the circuit through its terminals, and the pilot circuit, controlled by contactor 83, then is through wire 96 and wire 95 to one of the terminals of the contactor 83 and then from this contactor through wire 96 to solenoid 91 and on to wire 98 which connects to wire 93. When the solenoid 91 is energized, the armature lifts a pawl 99 which rotates a ratchet wheel I66, one quarter revolution. This swings a bridge I6I of a four pole switch I62 to connect the now open contacts thereof, and when the four pole switch is closed in this position, a circuit then is completed from wire 95 to wire I63, through the live points of switch I62 and through wire I64 and on to a second four pole switch I65. With the bridge I66 of the second four pole switch I65 amass? set to contact wire I, the circuit then continuesthrough the bridge to wire I01 and on to a motor starting solenoid I and through wire III back to wire 08 and to the secondary of the transformer.' When the solenoid III 'is ener-' giscd, the rocker of starter III for motor 02 is moved to close the contacts to complete the circuit from the main line to the valve motor 02. The valve motor 02 then operates to rotate the vertical shaft I! to rotate the valve plug 30 one quarter turn to thereby reverse the direction of flow through the strainers. While the valve plug is making its quarter turn, worm wheel 04 makes a complete turn so that at the completion of its rotation the roller 01 engages the arm 00 of the circuit breaker and swings bracket 00 to tilt the contactor II to cause the mercury to flow toward the terminals where it closes a circuit from wire 00, through wire III to the contactor I0 and then through wireII2 to solenoid Ill and on through wire Ill to wire 02 and back to the secondary of the transformer. When solenoid I II is energized, the armature is lifted and through the pawl I I! the second four pole switch III is actuated to cause the bridge to connect wire II to wire I01. This opens the circuit to solenoid Ill and the contactors of starter IIO are opened to stop the valve motor 02. The next time that the float rod is lowered and the solenoid 01 is energized, the bridge IOI will be rotated to contact wire I I6 to again actuate starter iii to operate motor 02.

With this electrical control equipment, in one position of lever I0, the pump motor runs, and in the other position the pump motor is idle and the valve motor rims until the valve has been rotated one quarter turn to reverse the direction of flow through the strainers. Should the four pole switches I02 and I0! accidentally be out of cycle. it will require an extra movement of arm I! to again bring them into cycle, but when the electrical equipment is once started, these two four pole switches ,trail one another properly.

A further provision is made to reverse the flow through the strainers one or more times when the pump motor runs for longer periods of time than normally, due to greater inrushes of liquids or sewage due perhaps to storms or other unforseen conditions. During such long periods of operation, it is desirable to reverse the flow through the strainers, one or more times during continued operation of the pump, to clean the accumulated solids from the system and to'pass them on through the discharge pipe. For socomplishing this result, a time clock or other time controlled mechanism is provided to allow a predetermined length of time for operation of the pump motor and then to cause one or more valve movements to reverse the flow. In the form shown, a time clock III is employed in which the winding I it of the motor is connected to wire ll through a wire H0 and through a contactor in the starter 01 so that when the rocker arm of the starter is actuated to close the circuit through the pump motor, the circuit for the time clock is also closed. From this contactor of the motor starter a wire I20 leads to the motor winding III and from this winding, a second wire I2I leads back to wire 93 to complete the circuit. Closing the circuit Just described starts the time clock motor. The time clock circuit is split and from wire I20 a lead passes to a solenoid I22 and from this solenoid, a wire leads to wire III to complete this circuit.

Thetimeclockhasatrainofspeedreducing gears I204. the last one of which may comprise a friction disci2l. When the solenoid I22 is energized it rocks a yoke I23b, which carries the final friction roller I22 of the gear train so that the friction roller I22 engages a disc.i24 and causes it to rotate slowly. This disc is provided with a series of circumferentially disposed holes I20 near its periphery to receive one or more pins I2 that may be inserted in selected holes to set up the cycles for reversing the flow through the strainers. These cycles may be in predetermined time periods of say five minutes, ten minutes or intervals to suit the characteristics of the sewage. The-disc I24 is provided with a weighted section I21 so that when otherwise released, it, will swing back to a zero point so that each new rotation will start at zero to maintain even time intervals. That is, when the time clock motor starts. solenoid I22 is also energized to swing the yoke I2lb and thereby engage the friction roller I23 with the disc I24 to set the disc in motion. Should the disc rotate through a time interval less than the predetermined period determined by pin I 26 and then the time clock motor stop, the solenoid I22 will be de-energized and the disc will return to zero, when free, so that no accumulative motion is had. In order that the disc may return freely to zero, the contact spring I 28 is mounted on a swinging arm I284 which is actuated by the solenoid I22 through a link. When the time clock is operating, this spring I28 is lifted so 1 that a hump of the spring is in the path of the pin I26. and when the pin engages the hump it causes the contactor I20 of the time switch to close the circuit from the transformer, through wire through the wire I 20 through contacts I20, I30 and then back through wire III to wire 00 leading to solenoid 91, and back through wires 98, 08 to the transformer. In other words, the time clock at predetermined periods, bridges across the terminals of contae tor 82 to actuate the four pole switch I02 as frequently as is desired.

In the positions of the parts as shown in Fig. 6, with the switch rod down, the circuit for the solenoid 01 is closed through contactor 03. The solenoid was energized when the float rod reached the bottom of its stroke and opened the pump motor circuit through the contactor 04. The solenoid 01, having been energized, has rotated the bridge IOI of the four pole switch I02 to bridge the contacts for wires I03, I I8. The circuit for starter solenoid I08 is open at the four pole switch I05. Now when the float rod is again raised to the top of its stroke, contactor 84 closes the pump motor circuit and contactor 83 opens the circuit controlled thereby, for the solenoid 01, permitting the armature to drop with the pawl 09 in position to engage a tooth of the ratchet wheel I00. The time clock mechanism begins to run as soon as the starter 81 is closed, but it does not have any effect until the pump motor has exceeded its time limit of operation. When the float rod drops it tilts the contacts 82, 04, thereby opening the motor starting circuit and closing the circuit for the solenoid 91 through contacter 03, and the solenoid being energized, the pawl 99 is raised, thereby advancing the ratchet wheel one tooth and swinging the bridge IIII across the poles for the wires I03, I04, thus closing the valve motor starter solenoid I00 through bridge I00 and wire I01. The valve motor isstarted, turning the valve plug the required distance to reverse the flow through the strainers, and as the worm wheel 64 rotates, the roller 6'! runs on the arm 60, which falls and tilts the contactor I0, breaking the circuit for the solenoid II3, permitting the pawl to drop into position to engage a tooth of the ratchet wheel Ia. When the worm wheel has made a complete rotation the roller 61 raises the arm 60, which tilts the contactor back to re-establish the circuit for the solenoid H3, which, being energized, lifts the pawl and advances the ratchet wheel I00a one tooth, thereby swinging the bridge I06 across the poles for the wires IIB, I01 and opening the circuit for the starter solenoid I08 through the poles for the wires I04, I01, thus stopping the valve motor. This sequence continues so long as the pump motor runs for normal periods of time.

If the pump motor continues to run for a greater period, the time clock mechanism being in operation, the friction roller rotates the disc I24 and carries the pin I26 around until it depresses the spring contact I and closes a circuit for the solenoid 91 through contacts I20, I30. The solenoid 91 is then energized and the bridge IOI thrown across the contacts of the four pole switch I02 for wires I03, H6, thereby closing the circuit for the valve motor starter solenoid I08,

through wires 90, I03, I I6, bridge I06 of the four pole switch I05 (which at this time is bridging the poles for wires IIE, I01), then through wire I01,

solenoid I08, wires I09 and 93 to the transformer, thereby starting the valve motor 62, which partially rotates the valve plug 39, and at the same time rotates the worm wheel 64, permitting the arm 68 to drop and open the circuit through the contactor 10, thus dc-energizing the solenoid H3 and permitting the pawl I I5 to drop to a position for engagement with the ratchet wheel I00a. When the worm wheel has been rotated through 360 the roller 61 raises the arm 68, swings the contactor 10 back to the position shown, closing the circuit through wires 90, III, II2, solenoid H3 and wires I I4, 93 back to thectransformer, thereby energizing the solenoid II3, which turns the ratchet wheel, I 00a, one tooth and throws the bridge I06 across the open contacts and opens the circuit for the solenoid I08 through lines I04, I01, thereby stopping the valve motor, until the time clock contacts I28, I are again closed by the pin I26, which again closes the circuit for the solenoid 91, which again shifts the bridge IOI, thus again closing the circuit through the other contacts thereof, the break in the circuit through the four pole switch I05 having been previously bridged as above set forth. These cycles of valve pump operations continue until the float rod is lowered, breaking the pump motor starter circuit.

The wiring from the main line 85 to the starter IIO for the valve motor 62 preferably includes a main line switch I 32 so that the line may be open for servicing the equipment.

In the operation of the pumping apparatus, liquid is admitted to the reservoir through the gate valve I I. The suction flow is through one of the set of pipes I8, I9, check valve 20, .J-fitting 22, T 23, strainer 21, elbow hub 3| and through the port or M, which then connects the elbow hub with the suction side of the pump. Discharge flow is through pipe 41, U-fitting 38, elbow hub 33 and through the port 40 or M, which then conmeets the elbow hub 33 with the other elbow hub 3|, thence back through the other strainer 21, T fitting 23, through check valve 42, elbow 43, T fitting 44 and thence through the discharge pipe 45. When the valve plu is shifted the flow is reversed through the strainers, the suction then being through the other set of piping, strainer and valve to the suction side of the pump. High liquid level in the wet well completes the motor circuit for the pump motor and the pump continues to run until the liquid level is lowered to that point where the motor circuit is broken.

If the inflow to the wet well is greater than the pump can dispose of, the time clock mechanism operates to periodically actuate the flow reversing valve so that the strainer will be flushed one or more times during the operation of the pump.

The electrical system shown and described for controlling the operation of the pump motor and the valve motor merely exemplifies one form of means for accomplishing those results. Obviously the time clock control mechanism for the valve motor may be omitted if desired, but it serves to frequently reverse the flow through the strainers in the event that the pump is required to operate continuously or for any considerable period of time, thereby preventing the strainers from becoming clogged. Furthermore, pressure operated means may be substituted for the electrical control mechanism of the apparatus to accomplish the same result. Various other alterations and modifications are possible without departing from the present invention and therefore I do not desire to limit myself to the exact mechanism shown and described, but intend to point out all of the invention disclosed in the appended claims:

I claim as new and novel, and desire to secure by Letters Patent:

1. Pumping apparatus comprising in combination a pump having a suction side and a discharge side, two intake conduits leading from a source of liquid supply, strainers, one in each intake conduit, a discharge conduit communicating with both intake conduits, flow reversing means alternately connecting said intake conduits, through the strainers with the suction side of the pump and simultaneously connecting the discharge side of the pump, alternately, through the strainers, with the discharge conduit, and

' means operating to periodically actuate said flowreversing means to thereby reverse the flow through said strainers.

2. Pumping apparatus comprising in combination a pump having a suction side and a discharge side, two intake conduits leading from a source of liquid supply, strainers, one in each intake conduit, a discharge conduit communicating with both intake conduits, a flow-reversing valve having ponts connecting either intake conduit, through the strainer with the suction side of the pump and simultaneously connecting the other intake conduit, through its associated strainer, with the discharge side of the pump, and means operating to periodically reverse said flow-reversing means to thereby reverse the flow through said strainers.

3. Pumping apparatus comprising in combination a pump having suction inlet and a discharge outlet, two check valve controlled intake conduits leading from a source of liquid supply, flow reversing means, strainers, one interposed between each intake conduit and the flow-reversing means, the latter having ports simultaneously connecting either strainer with the suction inlet of the pump and the discharge outlet of the pump with the otherstrainer, means to intermittently actuate said flow reversing means to reverse the flow through the strainers, a discharge pipe and check controlled connectionsbetween the discharge pipe and both intake conduits.

aaeasov 4. Pumping apparatus comprising a motor operated pump, two intake conduits leading from a source of liquid supply, a discharge pipe connected with both intake conduits, strainers, one connected with each intake conduit between its intake end and its connection with the discharge pipe, and flow reversing means between. both strainers and the inlet and discharge sides of the pump, in combination with means (or operating the flow reversing means and responsive to fluctuations or the level of the liquid supply.

5. Pumping apparatus comprising a motor operated-pump, two intake conduits leading irom a source of liquid supply, a discharge pipe connected with both intake conduits, strainers, one connected with each intake conduit between its intake end and its connection with the discharge pipe, flow reversing means between the strainers and the inlet and discharge sides of the pump, in combination with a motor for operating the flow reversing means, operable connections between said motor and flow reversing means and means responsive to fluctuations oi the level of the liquid supply for starting and stopping the pump motor.

6. Pumping apparatus comprising a motor operated pump, intake conduits leading from a source of liquid supply, a discharge pipe connected with both intake conduits, strainers, one connected with each intake conduit, and flow reversing means between the strainers and the suction and discharge sides 01 the pump, in combination with a motor for operating the flow reversing means, operable connections between said motor and flow reversing means, means responsive to fluctuations oi the level oi the liquid supply for starting and stopping the pumpmotor, and mechanism controlled by said last mentioned means to start the motor for the flow reversing means, said mechanism including means to stop the last mentioned motor.

'7. Pumping apparatus comprising in combination a pump having a suction side and a discharge side, a pump motor therefor, two sets of intake piping leading irom'a single source of liquid supply, strainers, one in each set of piping, flow-reversing means interposed between the strainers and the suction side and discharge side or the pump, electrical control means responsive to fluctuation oi the level of the liquid supply for starting and stopping the pump motor. electric motor operated means to operate said flowreversing means, electrical control me'ans operating subsequently to the stoppage oi the pump motor to start the motor oi! the flow-reversing means, and discharge piping in communication with the two sets of intake piping and the strainers.

8. Pumping apparatus comprising in combination a pump having a suction side and a discharge side, a pump motor therefor, two sets intake piping leading irom a single source of liquid supply, strainers, one in each set of piping, a flow-reversing valve interposed between the strainers and the suction side and discharge side of the pump, electrical control means responsive to fluctmtions oi the level 0! the liquid supply for starting and stopping the pump motor. electric motor operated means to operate said valve to reversethedirectionoiflowthroughthestrainere, electrical control means responsive to the motor of the valve operating means,electricalcontrol means to stop saidvalvemotonanda discharge pipe in communication with the two sets of intaking piping andstrainers.

9. Pumping apparatus comprising in combination a motor driven pump having a suction side and a discharge side, two check valve controlled intake pipes leading irom a fluctuating source oi liquid supply, each pipe having two branches, strainers, one connected to one branch 01' each pipe, a flow reversing valve having a caslng provided with connections with the suction side and discharge side of the pump and with the two strainers, and a four-way valve plug in said casing, having ports for connecting either strainer with the suction side of the pump and simultaneously connecting the other strainer with the discharge side of the pump, whereby the flow through the strainers may be reversed upon rotation of the valve plug, a discharge pipe having check valve controlled connections'with both intake pipes, motor operated means to periodically actuate the valve plug, said means being responsive to fluctuations oi the levels of the source of liquid supply and means to star-t and stop the pump motor controlled by fluctuations of the level of the liquid supply.

10. Pumping apparatus comprising in combination a, motor driven pump, intake pipe lines leading from a source of liquid supply, a strainer in each pipe line, flow reversing means interposed between the strainers and the suction side oi the pump, and between the discharge side 01 the pump and strainers, a discharge pipe having connections with each intake pipe line, starting and stopping means for the pump motor, responsive to fluctuationsoi the level of the liquid supply, and means for periodically actuating the flowreversing means for reversing the direction of the flow through the strainers.

11. Pumping apparatus comprising in combination a motor driven pump, intake pipe lines leading irom a source of liquid supply, a strainer low level-oi the liquid 81129 7 for the in each pipe line, flow reversing means interposed between the strainers and the suction side 01. the pump, and between the discharge side 01 the pump and strainers, a discharge pipe having connections with each intake pipe line, starting and stopping means for the pump motor, responsive to fluctuations oi the level of. the liquid supply, and means for periodically actuating the flow reversing means for reversing the direction of the flow through the strainers, said last mentioned actuating means being responsive to the pump motor starting and stopping means.

12. Pumping apparatus comprising in combination a motor driven pump, intake pipe lines leading r-rom a source 01 liquid supp a strainer in each pipe line, flow reversing means interposed between the strainers and the suction side of the pump, and between the discharge side 01 the pump and strainers, a discharge pipe having connections with each intake pipe line, starting ALFRED CHARLES PAGE-

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