GB2033060A - Pumping apparatus - Google Patents

Abstract

To prevent the head of water in the discharge pipe of a submersible pump from turning the pump and its submersible hydraulic drive motor in reverse when the pump is stopped, with consequent risk of blowout of sealing gaskets, a check valve is provided in the hydraulic circuit, e.g. in the motor supply line adjacent an above-ground pump in closed circuit with the motor. A bypass pressure regulating valve is connected to the outlet side of the hydraulic pump and viewing means is provided to enable oil flow in the circuit to be monitored. A manually operated bypass starting valve is also included in the circuit.

Description

SPECIFICATION Pumping apparatus This invention relates to a pumping apparatus of the type having a submersible pumping unit which includes a hydraulic motor, and an above-ground hydraulic system to drive the motor.

Submersible pumping units in use heretofore have included a hydraulic motor driving an axial flow pump, both the motor and the pump being mounted in a casing that is lowered into a water-filled ditch, trench or excavation in the ground to pump the water up through a discharge pipe from the axial flow pump. The hydraulic motor is connected through hoses or pipes to an above-ground pump, which pumps oil through the hydraulic motor to drive it, with the return flow of the oil going back to an above-ground tank which supplies the oil to the above-ground pump.

The hydraulic motor and the pump in the submersible pumping unit are stopped by turning off the above-ground pump. When this happens, the water in the discharge pipe above the submersible pump unit tends to flow back down by gravity and rotate the impeller of the submerged pump in reverse.

This pump, in turn tends to drive the hydraulic motor in reverse, causing the latter to pump oil in reverse through the above-ground pump. Also, the reversal of the impeller could result in a blowout of sealing gaskets for an oil-filled enclosure for a shaft coupling between the hydraulic motor and the pump in the submersible pump unit.

In the pumping apparatus of the present invention, the hydraulic system for operating the hydraulic motor in the submersible pumping unit includes a check valve on the outlet side of the above-ground hydraulic pump.

This check valve passes oil from that pump to the hydraulic motor in the submersible pumping unit but automatically blocks any reverse flow of such oil, thereby acting as a brake preventing reverse rotation of the hydraulic motor. A pressure regulating valve with a sight glass is connected in a bypass line extending between the outlet side of the above-ground pump and the low pressure return to the oil tank. This pressure regulating valve relieves any excess pressure and normally maintains a constant oil pressure for operating the hydraulic motor in the submersible pumping unit.

The apparatus may include a filter/strainer between the oil tank and the inlet of the above-ground pump to filter out any particles coming from the reservoir that might damage that pump.

Reference is made to the drawings, in which: Figure 1 is a schematic illustration of an apparatus in accordance with this invention; Figure 2 is an enlarged vertical section taken axially through the submersible pump ing unit in the Fig. 1 apparatus; and Figure 3 is a fragmentary vertical sectional view on an even more enlarged scale showing the pump shaft seal in the submersible pump ing unit.

The hydraulic system of the apparatus of the present invention is shown connected to a submersible pumping unit which includes a hydraulic motor 10 of know design mounted inside a casing 11 which, as shown, has an inclined intake scoop 11 a at its lower end.

The hydraulic motor 10 has a rotary output shaft coupled to the impeller of an axial flow pump of known design, which is located inside the casing 11 just abovr the intake scoop 11 a.

This submersible pumping unit may be lowered into a ditch, trench or excavation in the ground, or it may be held suspended in a vertical well casing in the ground or at a substantially horizontal irrigation conduit in the ground. The casing 11 of the submersible pumping unit may be suspended from cables extending down from a winch on a groundlevel mobile unit, such as shown in U.S.

Patent 3,907,463.

Fig. 2 shows the submersible pumping unit in detail. The sections of the annular casing 11 and its intake scoop 11 a are bolted or otherwise rigidly attached end-to-end.

The motor 10 is a rotary hydraulic motor of known design which is supported rigidly centrally inside the upper of casing 11. This motor has a hydraulic inlet 39, connected to the lower end of an inlet hose 12, and a hydraulic outlet 40 connected through a reversely-bent, rigid pipe 41 that extends down outside the hydraulic motor parallel to the axis of the pumping unit and has its lower end bent radially inward at 41 a.

A three-piece annular housing is sealingly engaged axially between the hydraulic motor 10 and the pump 42 in this underground pumping unit. This housing comprises an upper cylindrical section 43, a middle cylindrical section 44 and a bottom end plate 45. The upper cylindrical section 43 of this housing is bolted at an annular, radial flange 43a on its upper end to the casing of the hydraulic motor 10, and it is bolted to the middle housing section 44 at a similar flange 43b on its lower end. Suitable liquid-tight sealing gaskets 46 and 47 are engaged respectively between the upper end flange 43a and the motor casing and between the lower end flange 43b and the top of the middle housing section 44 to prevent leakage.

The inturned lower end 41 a of pipe 41 is rigidly connected through a metal fitting 48 to the upper housing section 43, and it communicates with the interior of this housing through this fitting.

At the opposite side of the upper housing section 43, the lower end of a return hose 1 3 (which extends back up to the sump in the mobile unit at ground level) is turned in radially at 1 3a and is connected here through a similar metal fitting 49 to the housing section 43, so as to pass hydraulic liquid from the interior of this housing to the return hose 13.

A connecting shaft arrangement of know design, designated in its entirety by the reference numeral 52, extends axially between the hydraulic motor 10 and the pump 42 to impart the rotation of the rotor in the motor directly to the pump rotor. It includes a slidable jaw coupling 52a connecting the output shaft IOaof the motor to the pump shaft 55 and permitting a certain amount of axial displacement of either shaft with respect to the other, such as in case of expansion or contraction with temperature changes. This connecting shaft arrangement extends centrally through the three-piece annular housing 43, 44, 45 and it is rotatably supported in the end plate 45 of this housing by an arrangement described hel;..a.w.. a liquid-tight seal 54 of known design prevents leakage around the pump shaft 55 at the lower end plate 45 of the housing.

An annular sealing gasket 63 is clamped axially between the end plate 45 and the middle housing section 44 ot prevent leakage between them.

A bearing assembly is engaged axially between the lower end of the upper housing section 43 and an internal upwardly facing, annular shoulder 56 on the middle housing section 44. In Fig. 5 this bearing assembly comprises, three ball bearings 57, 58 and 59 arranged end-to-end and each constituting both a radial bearing and an axial thrust bearing.

The lower-most of these bearings 57 has an annular inner race 60, an annular outer race 61, and balls 62 engaged radially between these races. The inner race 60 presents an upwardly-facing shoulder 60a below the balls 62 and the outer race 61 presents a downwardly-facing shoulder 61 a above these balls.

With this arrangement, the bearing units 57 will resist an upward axial thrust on the connecting shaft arrangement 52.

Both the middle bearing 58 and the upper bearing 59 have essentially the reverse configuration of the races, with the inner race having a downwardly-facing shoulder that engages the balls, and the outer race having an upwardly-facing ball-engaging shoulder. Consequently, both of these bearings 58 and 59 oppose a downward axial thrust on the connecting shaft arrangement 52.

It will be evident from Fig. 5 that the upper end of the upper bearing 59 conmmunicates with the interior of the upper housing section 43 around the connecting shaft arrangement 52. Consequently, the hydraulic liquid supplied through pipe 41 to the interior of this housing section 43 lubricates the bearings 59, 58 and 57 which support the connecting shaft arrangement for rotation and withstand axial thrusts in either direction on this connecting shaft arrangement.

The shaft seal 54 for the pump shaft 55 may be a "John Crane Type 1" seal sold by Crane Packing Co., Morton Grove, Illinois, U.S.A., and depicted in that company's bulletin S-255-3, or it may be a similar type of carbon-ceramic shaft seal made by other companies.

This shaft seal is located below a lock nut 75, which is threadedly mounted on a screwthreaded portion 55a of the pump shaft 55 directly below a washer 73 engaging the bottom of the lowermost bearing unit 57. An annular spacer 74 engages the bottom of the nut 75 and encircles the pump shaft 55 just below its screw threads 55a.

The seal shaft 54 includes a compression coil spring 76 whose upper end engages a retainer 76athat abuts against the bottom of the spacer 74. The lower end of this spring is seated against the upper end of an annular retainer 77 which holds a carbon mating ring 78 at its lower end. The nut 75, spacer 74, retainer 77 and mating ring 78 are rotatable, as a unit, in unison with the pump shaft 20.

As shown in Fig. 3, the mating ring 78 has a downwardly-offset, annular central segment 79 which bears down against a stationary ceramic ring 80. The engaging surfaces of the carbon and ceramic rings 78 and 80 are lapped to provide a fluid-tight seal around the pump shaft.

The stationary ring 80 is seated in a ringshaped holder 81 of rubber-like material, which is mounted in an upwardly-facing, central, annular recess 82 in the bottom retainer plate 45 of the three-piece housing 43, 44, 45.

The annular retainer 77 at its upper end has circumferentially-spaced, upwardly-facing notches or recesses which snugly receive corresponding radially outwardly-projecting fingers 83 on an annular driving band 84, which extends up from the retainer 77 inside the coil spring 76.

An annular, flexible and resilient bellows 85 of rubber-like material surrounds the pump shaft 20 and is held tightly against the shaft around the latter's entire circumference by the driving band 84 near its upper end. The lower end of this annular bellows is held against the top of the rotating mating ring 78 by the retainer 77. As best seen in Fig. 3, the retainer 77 is offset radially inward at 77a and just below this location a flat annular disc 86, which fits snugly inside the retainer 77, holds the radially autwardly-extending lower end lip of bellows 85 snugly against the top of ring 78. The bellows 85 has one or more folds along its length.

This particular type of shaft seal has been found to be advantageous in preventing the entry of foreign particles, normally found in water, from entering the bearings 57-59 and interfering with their extremely vital function of centering and rotatably supporting the pump shaft. In previous pumping installations of the axial-flow type the shaft seal has been the principal trouble spot because of its tendency to cause excessive wear on the pump shaft, which had the result of keeping the pump out of operation frequently and for relatively long periods of time. With the improved operation made possible by this particular shaft seal, the bearings 57-59 properly centre the pump shaft 55 and keep it aligned axially with the motor shaft 1 0a and produce no excessive wear on the pump shaft.In turn, this makes possible the use of the slidable jaw coupling 52a between these shafts, which prevents the axial expansion and contractions of the motor shaft 1 0a from being imparted to the pump shaft 55.

The pump 42 has a rotor consisting of a central hub 64, rigidly secured to shaft 55, and outwardly projecting, curved impeller blades 65 whose outer edges have a close running fit inside a cylindrical liner 66, which is secured to the inside of the lower section of casing 11 at the latter's lower end. A frustoconical nose 67 extends down axially from the rotor hub 64.

A plurality of circumferentially spaced, radially disposed spacers 69 are welded to the inside of the lower segment of casing 11 and have their inner ends welded to the outside of the middle housing section 44 to centre the three-piece housing 43-45 inside the casing 11.

At the same circumferential locations, a plurality of radially disposed spacers 70 are welded to the inside of the upper section of casing 11 and extend inward therefrom, terminating at their inner edges just short of the housing of the hydraulic motor 10.

These aligned radial spacers 69, 70 serve to channel the output flow from the propeller blades 65 into separate, substantially axial streams, which flow up inside the casing 11 and then merge with each other as they flow up into the well casing above this pumping unit.

The hydraulic motor 10 is driven in one rotational direction so that it will rotate the pump impeller 65 in a direction for pumping the water longitudinally through the casing 11 past the hydraulic motor. For this purpose the hydraulic motor 10 is provided with the aforementioned inlet hose 1 2 and return hose 13, both of which extend down to the hydraulic motor 10 from the aforementioned groundlevel mobile unit.

Referring again to Fig. 1, the upper end of the hydraulic motor inlet hose 1 2 is operatively connected to the outlet side of a constant volume vane pump 1 4 or other type hydraulic pump driven by a prime mover 15, which may be an electric motor or a diesel engine. The inlet side of the pump 14 is operatively connected through a normally open, manually operated gate valve 1 6 to the lower end of an oil tank 1 7. All of these components are in the above-ground mobile unit.

In accordance with one feature of the present invention, a screen type strainer/filter 1 8 is located between the outlet side of the gate valve 1 6 and the inlet side of the aboveground pump 1 4 to protect the latter against metal particles which sometimes are left inside the oil tank 1 7 when its side and bottom walls are welded to one another.

The outlet side of the above-ground pump 1 4 is connected through two successive Tfittings 1 9 and 20 to the inlet hose 1 2 for the hydraulic motor 1 0. In accordance with an important aspect of this invention, a check valve 21 of known design is connected between the second T-fitting 20 and the hydraulic motor inlet hose 12, for a purpose explained hereinafter. This check valve permits oil to flow from the pump 14 to the hose 1 2 but blocks oil from flowing the reverse direction.

The return hose 1 3 from the hydraulic motor 10 is operatively connected through an oil filter 22 of known design to the low pressure return line 23 for the oil tank 1 7.

A bypass circuit is connected between the outlet side of the above-ground pump 1 4 and the return line 23 for the oil tank. This bypass circuit includes a fitting 24 containing a pressure regulating valve of known design which has its inlet connected to the second T-fitting 20 at the outlet side of the pump. This pressure regulating valve has a bypass outlet connected through a line 25 to a return line 23. Whenever the pump pressure exceeds 2,000 psi, for example, the pressure regulating valve in fitting 24 bypasses the excess pump pressure to the return line 23. The valve 26a is opened to relieve pressure on the system for engine starting and closed to raise pressure to put system into operation; after closing this valve, operating pressure can be observed on psi gauge 28.

A fitting 25a having a viewing window is connected between the bypass outlet of the pressure regulating valve in the fitting 24 and the bypass line 25. The user of the present apparatus can observe the existence of a bypass flow into conduit 25 through fitting 25a and thereby be informed of any abnormality in the system's operation which might require a shut down or adjustment to correct the problem.

The pressure gauge 28 is connected in line 27, which is connected around regulating valve 24, and to the fitting 24 to provide a visual reading of the pump outlet pressure.

In the operation af this pumping unit, the pump 14 in the ground-level mobile unit (Fig.

1) pumps hydraulic liquid down through hose 12 to drive the hydraulic motor 10. The rotor in the hydraulic motor drives the pump 42 to draw in water through the intake scoop 11 a at the lower end of the casing 11 and force it up through the interior of casing 11 (around the outside of the housing 43-45) and up past the hydraulic motor 10 through the well casing. The hydraulic liquid flowing out of the motor 10 also lubricates the bearings 57-59 for the pump shaft 55. The return hose 1 3 provides a return path for hydraulic liquid flowing out of the housing 43-45 for the bearings 57-59.

The above-ground pump 14 also may be used to provide the motive for the winch 30 on the mobile unit that is used to lower and raise the submersible pumping unit.

The winch 30 is rotated by a reversible second hydraulic motor 31 having hydraulic lines 32 and 33 connected to the motor ports of a manually operated four-way valve 34 of the closed-centre type. Valve 34 has an inlet port at 35 which is connected to a line 36 leading from the first T-fitting 1 9 at the outlet side of pump 14. Valve 34 has a return port at 37 which is connected to the oil tank return line 23.

Normally, with the handle 34a of valve 34 in its centred position, this valve is closed and the winch 30 is not operated.

When the valve handle 34a is displaced in one direction from its closed-centre position, the valve inlet port 35 will be connected to the line 32 leading to one side of the hydraulic motor 31 and the other motor line 33 will be connected to the return port 37 of the valve. Consequently, the output pressure from the pump 14 will drive the hydraulic motor 31 to operate the winch 30 in the direction corresponding to the position of valve handle 34a.

When the valve handle 34a is displaced in the opposite direction from its closed-centre position, the valve inlet port 35 will be connected to the hydraulic motor line 33 and the other motor line 32 will be connected to the return port 37 of the valve. Consequently, the hydraulic motor 31 will be operated in the opposite direction by the output pressure from the pump 14 so as to drive the winch 30 in that direction.

When the submersible pumping unit is stopped (by turning off the above-ground pump 14), the water in the discharge hose 1 3 tends to flow back down through the casing 11 and rotate the impeller 65 of the submerged pump in the reverse direction from its normal pumping direction (when driven by the hydraulic motor 10). Such reverse rotation of the pump impeller would be imparted to the hydraulic motor 10, causing the latter to operate in reverse and pump oil from hose 1 3 into hose 1 2. (It will be understood that under these conditions the submerged pump now is acting as a hydraulic motor and the hydraulic motor 10 is acting as a pump). This reverse flow could be damaging to the below-ground pump 11 and the above-ground pump 14 in the present hydraulic system.

In addition, this reverse flow could contri ute to a build-up of pressure inside the housing section 43 between the hydraulic motor 10 and the pump 42 which might cause either or both sealing gaskets 46 and 47 for this housing section to be blown out. The replacement of these gaskets would be time consuming and expensive.

The aforementioned check valve 21 prevents these undesirable effects from taking place. In effect, the check valve 21 acts as a hydraulic brake which prevents the hydraulic motor 10 from being reversed as a result of the downward rush of water through the casing 11 and over the impeller of the submerged pump.

While the check valve 21 preferably is located between the outlet of the aboveground pump 14 and the inlet hose 12 for the hydraulic motor 10, it is to be understood that the check valve could be located between hose 1 3 and filter 22, if desired.

Claims (4)

1. A pumping apparatus comprising a submersible pumping unit having a rotary water pump including an impeller for pumping water up from the ground, a hydraulic motor for rotating said pump in one direction and hydraulic feed and return lines connected to the hydraulic motor, an above-ground hydraulic system for operating the hydraulic motor and including an oil tank, a hydraulic pump operatively connected to pump oil from the tank to the hydraulic feed line to drive the hydraulic motor, and return conduit means connected between the hydraulic return line and the oil tank to return the oil from the hydraulic motor to the tank, check valve means operatively connected in circuit with the lines and the hydraulic motor for preventing the motor from being operated in reverse by the downward flow of water through the water pump acting on the impeller when the hydraulic pump is shut off, a bypass pressure regulating valve connected with oil viewing means between the outlet side of the hydraulic pump and the return conduit means for the oil tank to limit by bypass oil flow the pressure of the oil which operates the hydraulic motor, the oil viewing means enabling viewing of bypass oil flow for adjustment purposes, a bypass line connected in parallel around the pressure regulating valve, a manually-operable valve in the bypass line to be opened when starting the hydraulic pump to relieve hydraulic pressure and then closed for operation, and a pressure gauge in the bypass line for indicating hydraulic pressure.

2. A pumping apparatus according to Claim 1, wherein the check valve means is connected between the outlet side of the hydraulic pump and the hydraulic feed line.

3. A pumping apparatus according to Claim 1 or 2, wherein the submersible pumping unit includes a coupling unit, bearings, and a rotary seal.

4. A pumping apparatus, substantially as described with reference to the drawings.