US3785753A

US3785753A - Electric drives for centrifugal pumps

Info

Publication number: US3785753A
Application number: US00188732A
Authority: US
Inventors: A Bogdanov; Z Pomazkova
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-10-13
Filing date: 1971-10-13
Publication date: 1974-01-15
Anticipated expiration: 1991-01-15

Abstract

An electric drive for a submergible pump employed in oil production industry has a vertical oil-filled electric motor the lower portion of which is secured to a hydraulic compensator or surge chamber, while the upper portion is secured to a protector; the protector consists of a casing hermetically divided by a diaphragm into inner and outer chambers to be filled with protective liquid; an intermediate shaft is provided for transmitting rotation from the electric motor to the pump, the shaft having a sealing device concentrically disposed within the casing of the protector; a movable portion of the sealing device is fixed in the axial direction relative to a stationary portion of the same by means of a sliding bearing and two ring pivots disposed at both sides of said bearing. A release valve disposed in the casing of the protector is provided for controlling any excessive pressure in the space above the movable portion of the sealing device.

Description

[' Jan. 15, 1974 Primary Examiner-C. J. Husar Att0rney--Holman & Stern v [57] ABSTRACT An electric drive for a submergible pump employed in oil production industry has a vertical oil-filled electric motor the lower portion of which is secured to a hydraulic compensator or surge chamber, while the upper portion is secured to a protector; the protector consists of a casing hermetically divided by a diaphragm into inner and outer chambers to be filled with protective liquid; an intermediate shaft is provided for transmitting rotation from the electric motor to the pump, the shaft having a sealing device concentrically disposed within the casing of the protector; a movable portion of the sealing device is fixed in the axial direction relative to a stationary portion of the same by means of asliding bearing and two ring pivots disposed at both sides of said bearing. A release valve ELECTRIC DRIVES FOR CENTRIFUGAL PUMPS Inventors: Alexandr Antonovich Bogdanov,

Strastnoi bulvar, 7, kv. 39; Zinaida Sir'afimovna Pomazkova, Starokashirskoe shosse, 2, korpus l2, kv. 96, both of Moscow,

U.S.S.R.

Oct. 13, 1971 Appl. No.: 188,732

References Cited UNITED STATES PATENTS mh "c a "e S LM .m e hF United States Patent Bognanov et al.

[22] Filed:

disposed in the casing of the protector is provided for controlling any excessive pressure in the space above the movable portion of the sealing device.

1 Claim, 2 Drawing Figures Arutunoff..................... Arutunoff.,............ Myers Komor....

Sones Sanger ELECTRIC DRIVES FOR CENTRIFUGAL PUMPS BACKGROUND OF THE INVENTION The present invention relates to submergible pumps and, more particularly, to electric drives for centrifugal pumps, screw-type pumps, etc. used in oil industry for recovery of petroleum.

DESCRIPTION OF PRIOR ART metically divided by a diaphragm into an inner and outer chambers filled with fluid and an intermediate shaft for transmitting power from the electric motor to the pump having a packing device concentrically arranged with said casing.

In the known oil-filled electric drive the duration of uninterrupted of operation of the pump in a well is determined by the reserve of protective fluid and its consumption through the packing devices located on the shaft of the protector mounted in the casing of the protector. The reliability of operation of the above-said packing devices and the pressure within the casing determine the reliability and service life of the electric. drive as a whole. However,.the known electric drive which is not specifically designed for taking the axial thrusts from the pump driven by the electric motor (as in the machine according tov USA .Pat.'- No. 3,475,634, Cl. 310-87) isliable to have a low'reliability and a reduced service life due to the absence of special bearings which would take the axial thrusts, thus fixing the movable portion of the packing device relative to its stationary portion located within the protector casing as well as dueto the fact that the pressure within the space above the said packing device can exceed'its rated value.

Furthermore, the absence of a device for controlling excessive pressures in the electric'drive might result in failure of the components of the drive, primarily of the packing and flexible elements, which occurs both during operation-of the pump and in the case of a low external pressure, for example, when withdrawing the submerged unit from. the liquid in the well.

DESCRIPTION OF THE INVENTION 1 An object of the present invention is to eliminate the These and other objects are attained owing to the fact that a movable portion of the packing device in the electric drive is disposed in the axial direction relative to a stationary portion thereof disposed in the protector casing by means of a sliding bearing mounted into a protector casing and two pivots arranged at both sides of said bearing, while any excessive pressure in the space above the packing device is controlled by a release valve mounted in the protector casing.

The application of the proposed invention prolongs the uninterrupted period of operation of the .electric drive between overhauls, and provides for reliable and proper 'mounting of the pumping equipment of a well and makes it'possibleto avoid failures of the members of the electric drive in the process of its withdrawal from the well.

BRIEF DESCRIPTION OF DRAWINGS Theinvention will be better understood from a consideration of the following detailed description of one particular embodiment of the invention, reference being made to the accompanying drawings, in which:

FIG. 1 shows diagrammatically oil-filled electric drive for submergible pumps, partly in section;

FIG. 2 is a sectional view taken along the line 11-11 in FIG. 1. I

DESCRIPTION OF THE EMBODIMENT I The electric drive for submergible pumps comprises a vertical oil-filled electric motor 1 (FIG. 1), a hydrau- -lic compensator or surge chamber 2 connected to the and is separated from the inner space of the electric motor 1 by the flexible diaphragm 4 and the seal 5.

The seal 5 is arranged on-the shaft 6 concentrically about the shaft 6 and the casing of the protector 3.

Located within the casing of the protector 3 is a valve 7 which admits fluids from a reservoir in which the vertical motor and pump 16 are submerged into the chamber, B after the protective liquid filling this chamber has been expended. Extending along the chamber B and mounted rigidly on an inside wall of the protector 3 is a pipe 8 which serves as a connecting passage be tween the chambers above and above and below the pipe 8 even when the diaphragm bears against the walls of the body of the protector 3 as shown by the dotted lines in FIGS. 1 and 2.

. Mounted on the shaft 6 of the protector is a blade wheel 9 employed for creating a high pressure in the protector. 3. The shaft 6 of the'protector is mounted in

bearings

10 and 11, fixed in the casing of the protector 3 and is provided with two ring pivots l2, 13. The shaft 6 of the protector- 3 is connected to the shaft 14 by means of coupling 21 of the electric motor I.- A ring pivot 13 bears against the face of the sliding bearing 10 and does not allow the protector shaft to move upwards thereby providing for the contact in the working pair of the seal and for its reliable operation. Said shaft 6 of the protector is also connected by coupling 21 to a shaft l5-of a pump 16. A. ring pivot 12 by virtue of its location does not allow the shaft 6 to move downwards-thereby providing for precise mounting of the protector 3, the pump 16 and the oil-filled electric motor 1 and for normal operation of the seal 5.

Also mounted on the shaft 15 of the pump 16 is a thrust bearing 17 taking the axial load of the pump and a stuffing box 18.

Mounted in the casing of the protector 3 is a valve 19 connecting the chamber B with the ambient medium and releasing the protective fluid and gas from the chamber B of the-protector 3 under the conditions of an excessive pressure.

Connected to the lower portion of the oil-filled electric motor 1 is a surge chamber-2 with a flexible container 20.

The oil-filled electric drive operates as follows.

The oil-filled electric motor 1, the flexible container 20 of the surge chamber 2 and the chambers A and B of the protector 3 are filled with protective and lubricating fluid, in which case the diaphragm 4 bears against the inner wall of the protector casing as shown in FIG. 1.

The electric motor 1, the chambers A and B of the protector 3 can be filled with protective fluids either of the same or of different viscosity.

in the embodiment of the invention under consideration the chamber B is filled with protective fluid having a high viscosity than that filling the chamber A and the electric motor 1. 1

After switching on the electric motor 1 (FIG. 1), rotation is transmitted from the shaft 14 to the protector 3 and then to the shaft 15 of the pump 16.

The protective fluids filling the electric motor 1 and the chambers A and B of the protector 3 are heated and they expand. The increase in the volume of this fluid in the electric motor 1 and the chamber A is made up for by the deformation of the flexible container 20 of the surge chamber 2, while 'in the chamber B it is compensated for by the opening of the valve 19, in which case the diaphragm 4 moves from its initial position, i.e., from the inner wall of the casing of the protector 3, and levels the pressure in the chambers A and B, that is, the pressures in the spaces under and above the seal 5. The movable portion of the seal rotates together with the shaft 6, thus sliding along its stationary portion 5a mounted in the casing of the protector 3. The sliding surface between the movable portion of the seal 5 and the stationary portion 5a thereof is lubricated at the expense of the protective fluid forced from the chamber A due to the action of centrifugal forces and the small excess pressure in the chamber A.

The opening of the valve 19 eliminates the possibility of creating hihg excessive pressures in the chamber B and the back flow of high-viscosity protective fluid through the seal 5 from the chamber B into the chamber A, as well as the action of these pressures on the diaphragm 4 of the protector 3.

During the operation the ring pivot 13 bears upon the face of the bearing and retains the movable portion .of the seal 5 relative to its stationary portion 5a, thus providing for required values of specific pressure on the contact surfaces of the friction pair of the seal 5 as well as required consumption of the protective fluid admitted from the chamber A through the seal 5.

The blade wheel 9 rotates together with the shaft 6 of the protector 3, in which case a high pressure is developed in the chamber A which through the diaphragm 4 is transmitted to chamber B. The viscous fluid filling this chamber is admitted to the thrust bearing 17 and the stuffing box 18.

The consumption of high-viscosity fluid through the stuffing box 18 of the pump 16 is far in excess of that of low-viscosity fluid filling the electric motor 1 and the chamber A through the seal 5, therefore the diaphragm 4 gradually moves to the external walls of the casing 3 due to the pressure of the column of fluid contained in the well upon the flexible container 20 of the surge chamber 2 as well as the flow of the protective fluid from the container 20 into the chamber A of the protector 3. As soon as all the viscous fluid is consumed from the chamber B, well liquids start flowing into the lower portion of the chamber B.

The pipe 8 serves as a connecting valve between the upper and lower portions of the chamber B when the diaphragm 4 bears against the walls of the casing of the protector 3 (shown by dotted lines in FIGS. 1, 2).

As the well liquids enter the chamber B, the latter serves as a settler separating the reservoir water from the oil, the oil .moving upwards to the bearing 17.

As the protective fluid flows out from the chamber A, the diaphragm 4 begins moving to its initial position owing to the inflow of the reservoir fluids through the valve 7 into the chamber B. The changes in the volume of the protective fluid during starting and stopping of the electric drive are made up for by the flexible container, 20 and the diaphragm 4.

Asall the low-viscosity protective fluid filling the flexible container 20 and the chamber A is consumed through the seal 5, the cycle of operation of the electric drive in the well is over.

The consumption of protective fluid through the seal 5, and therefore, the entire operating cycle of the electric drive in the well depends on the correct position of the movable portion of the seal 5 mounted on the shaft 6 relative to its stationary portion 50 mounted in the casing of the protector 3 and also depends on the pressures acting in the spaces under and above the seal 5 controlled by the valves 19 and 7 located within the casing of the protector 3.

After completing the operating cycle and withdrawing the unit from the fluid in the well, the pressure in the inner space of the electric drive first drops down rapidly and then starts raising due to the evolution of the gas from the protective fluid (this gas in the dissolved state during the operation of the pump). The electric drive is under the pressure due to the presence of the dynamic or static level of the fluid in the well. This pressure is transmitted through the flexible container 20 and the diaphragm 4 of the protector 3 from the chamber A to the chamber B. The valve 19 opens and the fluid and gas are vented from the chamber B. When the diaphragm 4 bears against the external wall of the casing of the protector 3 (as shown by the dotted lines in FIGS. 1,2), the chambers A and B are connected through the open seal 5). The valve 19 protects the components of the electric drive from damage, in particular, it protects the flexible container 20 of the surge chamber 2 against breaking.

We claim:

1. An electric motor drive for submergible pumps comprising in combination: a vertical oil-filled electric motor; a hydraulic compensator connected to the lower portion of said electric motor; a protector connected to the upper portion of said electric motor and including a casing, said casing being divided by a flexible diaphragm into inner and outer chambers to be filled with a fluid; a submergible pump disposed above fixed in an axial direction relative to said stationary portion which is disposed in said casing of said protector by means of a sliding bearing mounted into said casing; two pivots arranged at both sides of said bearing; a release valve mounted in said casing of said protector and providing for control of any excessive fluid press'u'rewithin a space above the movable portion of the sealing device.

Claims

1. An electric motor drive for submergible pumps comprising in combination: a vertical oil-filled electric motor; a hydraulic compensator connected to the lower portion of said electric motor; a protector connected to the upper portion of said electric motor and including a casing, said casing being divided by a flexible diaphragm into inner and outer chambers to be filled with a fluid; a submergible pump disposed above said protector having a shaft arranged to be substantially aligned with a shaft of the electric motor; an intermediate connecting shaft of said protector having one end connected to said electric motor shaft and the other end connected to the shaft of the submergible pump; a sealing device concentrically disposed in the casing of said protector and having a stationary portion, and a movable portion of said sealing device which is disposed on said shaft of said protector and fixed in an axial direction relative to said stationary portion which is disposed in said casing of said protector by means of a sliding bearing mounted into said casing; two pivots arranged at both sides of said bearing; a release valve mounted in said casing of said protector and providing for control of any excessive fluid pressure within a space above the movable portion of the sealing device.