RU2532641C1 - Submersible pump set - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to the field of pump equipment and may be used to lift fluid from large depth. A submersible pump set comprises a body and an elastic shell filled with oil. The external surface of the shell communicates with the well cavity. The master shaft of the reversible electric motor is connected with a screw of a rolling screw-motion drive and with a rod of a pump drive compacted in the body. Both ends of the screw are installed in bearings. The upper bearing is located inside an insert aligned and fixed in the body by keys. A nut of the rolling screw-motion drive is connected with a hollow stem having slots and made as capable of making reciprocal movements in the bearings installed in keys on supports. The upper damper is installed on a hollow stem, and the lower one - inside the hollow stem. Increased reliability of operation of a submersible pump set and increased resources of rolling screw-motion drive due to prevention of its damage, arising due to twisting and axial load, and also a possibility to increase critical frequency of screw rotation.

EFFECT: extended overhaul period of a submersible pump set.

2 dwg

Description

The invention relates to the field of pumping equipment and can be used to lift liquids from great depths.

A ground-based drive of a sucker-rod pump is known, comprising an electric motor kinematically connected with a two-way screw-nut transmission screw. When the screw rotates, the nut connected to the rods makes reciprocating movements in the axial direction along the vertical guide [RF Patent No. 2133875 from 1999.07.27]. The disadvantage of the drive is its quick wear and short transmission life of the screw-nut sliding and low efficiency, due to high friction losses.

Also known is a surface drive of a borehole plunger pump comprising at least two parallel-mounted ball screw drives of rods from a reversible electric motor. The drive nuts connected by a traverse to a polished rod perform a reciprocating motion. The screws are connected to the electric motor and protected from the environment by corrugated elastic shells. At the upper and lower points of the housing, limit switches are installed to switch the reverse of the electric motor, as well as emergency voltage relief switches [US Patent No. 5,405,767 of 1995.01.05]. The disadvantages of the drive are as follows.

1. The dimensions of the drive, consisting of two or more parallel ballscrews and crossheads, do not allow it to be used in the submersible version.

2. Insufficient sealing of the ball screw drive, which makes it inoperative when immersed in the well.

3. The use of limit switches to control engine reverse and emergency shutdown in well conditions is associated with a separate cable line laying, which reduces the reliability of the unit as a whole.

The closest technical solution (prototype) is a submersible pump unit, comprising a housing, an elastic shell, a reversible electric motor, the drive shaft of which is connected to a screw-nut rolling screw, which is in a movable connection with the housing and connected to the pump drive rod, the rod is sealed in the housing and connected to the nut by means of a hollow rod that encloses the screw and enters into the movable connection with it, and the internal cavities of the housing and the elastic shell are filled with oil, and the outer surface be shell communicates with the cavity of the well and on the screw stem and the floor mounted dampers, wherein the hollow stem is in oil-filled elastic shell [RF patent №2347947 from 2007.09.04]. The disadvantages of the drive are as follows.

1. Quick wear and short transmission life of the screw-nut rolling, due to the method of fixing the screw only in the lower position.

2. The mismatch of the required dynamic loads that occur during operation of the transmission screw-nut rolling.

The technical effect of the invention is to increase the reliability of the submersible pump unit and increase the transmission resource of the rolling screw-nut due to the prevention of its destruction resulting from torque and axial loads, as well as the possibility of increasing the critical rotational speed of the screw.

The claimed technical effect is achieved by solving a technical problem aimed at increasing the overhaul period of a submersible pump unit.

The stated technical problem is solved due to the fact that in the submersible pump assembly containing the housing and the elastic shell filled with oil, the outer surface of the shell communicating with the cavity of the well, a reversible electric motor, the drive shaft of which is connected to the transmission screw screw-nut and the drive rod a pump sealed in the housing, both ends of the screw are installed in the bearings, while the upper bearing is located inside the insert, centered and fixed in the housing by keys. The screw nut of the rolling screw-nut is connected to a hollow rod having grooves and made with the possibility of reciprocating movements on bearings installed in the keys on the bearings. The upper damper is mounted on the hollow stem, and the lower inside the hollow stem.

The essence of the proposed unit lies in the fact that due to the centrifuged and fixed transmission screw the screw-nut rolling screw managed to increase the overhaul period of the pump unit, the installation of the lower damper in the hollow rod significantly reduced the dimensions of the product, and the use of sliding bearings to reduce friction losses during movement along them of the longitudinal groove of the hollow rod.

Figure 1 schematically shows a downhole pumping unit.

In Fig.2 - the attachment site of the upper end of the transmission screw screw-nut rolling.

The pump unit contains an oil-filled housing 1 connected to a reversible electric motor 2 provided with a hydraulic protection. The electric motor 2 is connected by a cable to a control station mounted on a surface (not shown). The shaft 3 of the motor 2 through the intermediate shaft 4 is connected coaxially with the screw 5 and the nut 6 of the rolling gear.

The intermediate shaft 4 is installed inside the oil-filled elastic shell 7, the cavity of which communicates with the cavity of the housing 1, and the outer surface with the cavity of the well. The lower part of the elastic shell 7 is sealed with an annular seal 8. In the upper part of the housing 1 on the rod of the pump 9 is installed the upper damper 10. The lower damper 11 is located inside the hollow rod 12, made with longitudinal grooves 13.

The lower end of the screw 5 and the intermediate shaft 4 are installed in the bearings 14, 15 and 16. The upper end of the screw 5 is installed in the bearing 17 located inside the insert 18, fixed and centered in the housing 1 by the keys 19, in which bearings 21 are mounted on the bearings 20.

The hollow rod 12 is connected by a rod 9 to a pump 22 having inlet openings 23. The rod 8 is sealed in the housing 1 by an annular seal 24.

The unit operates as follows. The rotation of the shaft 3 of the reversible electric motor 2 is transmitted by the intermediate shaft 4 to the screw 5 of the transmission screw-nut rolling. The hollow rod 12 together with the transmission nut 6 through the grooves 13 is made with the possibility of reciprocating movements to the upper (lower) position inside the housing 1 by sliding bearings 21 installed in the keys 19 on the supports 20. The rod 12 moves the plunger of the pump 22 to the rod 9, the fluid is supplied through the inlet 23, and the stroke length of the plunger of the pump 22 corresponds to the number of revolutions of the engine 2 in one direction. Upon reaching the specified number of revolutions of the engine 2 in one of the directions (corresponding to the stroke length of the plunger of the pump 22), the direction of rotation of the electric motor 2 and, accordingly, the direction of movement of the plunger changes.

When the reciprocating movement of the hollow rod 12 is free flow of oil in a closed system from the elastic shell 7 to the housing 1 and vice versa, providing lubrication of the transmission of the screw-nut rolling, waterproofed by O-rings 8 and 24.

The advantages of the proposed pump unit are that this design ensures the reliability and regulation of the operation of the submersible pump unit, while the transmission resource of the rolling screw-nut is increased, the critical rotational speed of the screw is increased, and the overall dimensions are reduced.

Claims (1)

The submersible pump unit, including the casing and the elastic casing, is filled with oil, the outer surface of the casing communicating with the cavity of the well, dampers, a reversible electric motor, the drive shaft of which is connected to the transmission screw screw-nut and the pump drive rod sealed in the casing, the lower end of the screw installed in the bearing, characterized in that the upper end of the transmission screw of the rolling screw-nut is fixed in the bearing located inside the insert, centered and fixed in the housing with keys, ha Single-nut screw transmission is connected with a hollow rolling stock having longitudinal slots and adapted to make reciprocating movement by bearings mounted in keyed on supports, the lower damper is mounted within the hollow rod.

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