RU2347947C1 - Deep-well pump unit - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to pumps and can be used for liquid upwelling. The proposed pump unit comprises a housing, elastic enclosure, reversing motor with its driving shaft coupled with the screw of the rolling feed-nut drive articulated with the housing and the pump drive rod. The rod is fitted tight inside the housing and coupled with the nut via a hollow con rod, an external member of the screw to making with it a flexible point. The housing and elastic enclosure inner spaces are filled with oil. The enclosure outer surface communicates with the well space. Note that the screw and hollow con rod accommodate a damper. Note also that the said hollow con rod is seated in oil-filled elastic enclosure.

EFFECT: higher reliability and expanded applications.

2 cl, 2 dwg

Description

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

Known borehole electrohydraulic pump unit containing a submersible motor connected to an oil pump equipped with an oil tank with volume compensator. The oil pump provides a hydraulic motor drive that converts the rotation of the electric motor into reciprocating motion of the piston of the pump equipped with suction and discharge valves [RF Patent No. 2166668 of 2001.04.05].

The pump unit has the following disadvantages:

- low reliability due to the presence of two additional complex units: oil pump and hydraulic motor;

- low efficiency and productivity associated with significant hydraulic resistance of these units when pumping oil under high pressure and large friction losses.

Also known is a surface drive of a sucker rod pump containing an electric motor kinematically connected to 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 rapid wear and short transmission life of the screw-nut slip and low efficiency due to high friction losses.

The closest technical solution (prototype) is a surface drive of a borehole plunger pump containing at least two parallel-mounted ball-screw drive 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 ball-screw gears and crosshead, do not allow it to be used in the submersible version.

2. Insufficient sealing of the ball screw drive, which makes it inoperative submerged 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 objective of the invention is to increase the reliability of the submersible pump unit and expand the scope of its application.

To solve the problem in a submersible pump unit, comprising a housing, an elastic shell, a reversible electric motor, the drive shaft of which is connected to a screw-rolling nut transmission screw located in a movable connection with the housing and connected to the pump drive rod, according to the invention, 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 body and elastic shell are filled with oil, and the outer surface bolochki hole communicates with the cavity and on the screw rod and dampers installed floor, wherein a hollow stem located in the oil-filled elastic shell.

These signs can eliminate the disadvantages inherent in the prototype due to the coaxial arrangement of the screw-nut rolling gear enclosed in an oil-filled sealed cavity, including at least one elastic shell, ensuring the balance of oil pressure in the housing with the pressure in the well, and two dampers, which ensure their interaction with the nut increases the current strength of the electric motor, signaling the need for reverse or emergency shutdown.

We are not aware of devices having a combination of the above characteristics, which means that the proposed device meets the requirements for inventions.

Figure 1 and 2 schematically shows a downhole pumping unit.

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 electric motor 2 through the intermediate shaft 4 is connected coaxially with the transmission 5 screw 6 - nut 7 rolling. The nut 7 through the protrusions 8 enters into a movable connection with the grooves 9 made in the housing 1, providing longitudinal movement of the nut 7 and the coaxial hollow rod 10 connected to it, moving outside the screw 6. The intermediate shaft 4 is installed inside the oil-filled elastic shell 11, the cavity of which is connected with a body cavity 1, and the outer surface with a well cavity. The lower damper 12 is installed in the lower part of the screw 6. The upper damper 13 is installed in the upper part of the hollow rod 10. The dampers 12 and 13 are made in the form of springs.

The lower part of the elastic shell 11 is sealed by an annular seal 14. The hollow rod 10 is connected by a polished rod 15 to a pump 16 having inlets 17. The rod 15 is sealed in the housing 1 by an annular seal 18. The screw 6 and the intermediate shaft 4 have bearings 19 and 20. Screw 6 enters with a hollow rod 10 in a movable connection by means of a bearing 21.

To improve the sealing of the oil-filled cavity of the unit, the hollow rod 10 can be located in the oil-filled corrugated shell 22 (figure 2), the upper part of which is fixed on the hollow rod 10, and the lower one on the body 1. The outer surface of the elastic corrugated shell 22 communicates with the cavity of the well.

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 6 of the transmission 5 rolling screw-nut. Since the nut 7 of the transmission 5 enters into a movable connection with the grooves 9 of the housing 1 by means of the protrusions 8, a longitudinal movement of the nut 7 and the hollow rod 10 connected to it takes place to the upper (lower) position. The rod 10 moves the rod 15 of the plunger of the pump 16, the fluid into which flows through the inlets 17, and the stroke length of the plunger of the pump 16 corresponds to the number of revolutions of the engine 2 in one direction. Bearings 19, 20 and 21 provide a fixed-simple way to mount the gear 5 rolling screw-nut.

When the nut 7 moves down and the spring of the damper 12 is compressed, the current of the motor 2 increases, therefore, with the known characteristic of the spring of the damper 12, the change in the current strength corresponds to deformation of the spring or movement of the nut 7. The motor 2 is reversed and rotated by a certain number of revolutions corresponding to the upward movement nuts 7, hollow rod 10, rod 15 and plunger of the pump 16, taking into account the deformation of the spring. After that, the rotation of the shaft 3 of the motor 2 is reversed and the nut 7 is moved down and the rod 10, rod 15 and pump plunger 16 connected with it.

If the countdown of the number of revolutions of the engine 2 and the emergency exit of the nut 7 fail above the extreme upper position, the hollow rod 10 rests against the housing 1 by the spring of the damper 13, which leads to an increase in the current in the engine 2 and its shutdown by the control station. Similarly, when the nut 7 exits below its lowermost position, it abuts against the spring of the lower damper 12, and if the deformation exceeds the deformation value during reversal, the motor current exceeds a predetermined value and the motor 2 stops.

When the reciprocating movement of the rod 10 is free flow of oil in a closed system from the elastic shell 11 to the housing 1 and vice versa, providing lubrication of the gear 5, waterproofed by O-rings 14 and 18. In this case, the elastic shell 11 is not loaded, and the pressure drop across the seals 14 , 18 is close to zero, since the pressure in the housing 1 is in equilibrium with the pressure in the well. In this case, only the seal 18 is in contact with the well fluid, since the seal 14 is in contact with the hydraulic oil of the engine 1.

When using a corrugated elastic shell 22 instead of an annular seal 18, a significantly greater tightness of the cavity of the housing 1 is ensured, excluding the contact of its cavity and the borehole fluid.

As a gear 5, a rolling screw-nut can be used ball screw or roller screw transmission.

The proposed pump unit provides significant pressure while saving energy and reliability.

Claims (2)

1. Submersible pump unit, comprising a housing, an elastic shell, a reversible electric motor, the drive shaft of which is connected to a transmission screw screw-nut rolling, which is movably connected to the housing and connected to the pump drive rod, characterized in that the rod is sealed in the housing and connected with a 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 body and elastic shell are filled with oil, and the outer surface of the shell communicates with the cavity Azhinov, and on the screw and the floor stock dampers are installed. 2. Submersible pumping unit according to claim 1, characterized in that the hollow rod is located in an oil-filled elastic shell.

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