RU2484306C1 - Protector for hydraulic protection of submersible oil-filled electric engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: protector for hydraulic protection of a submersible oil-filled electric motor includes a housing, a shaft with end seals arranged in the zone of nipples with axial holes and support bearings, an assembly of a bearing plate with the shaft support, which is arranged in lower part of the protector and combined with the base assembly, a head and a base. Bearings are located along the shaft in axial direction between the head and the base with formation of hydroseal chambers. In the protector head, in upper part above the protective casing of upper end seal there fixed is a water motor on the shaft. In the head there are holes interconnected with annular space and coinciding with the axis of holes of the water motor.

EFFECT: improving operating reliability of hydraulic protection of a submersible electric motor.

1 dwg

Description

The invention relates to the field of electrical engineering, namely to the tread protection of submersible motors designed to work in the submerged state and used as a drive in submersible pumping units for the production of formation fluid from oil wells.

When producing oil reservoir fluid from oil wells using electric submersible centrifugal pump units, submersible electric motors with tread protection of various designs and dimensions are used as the pump drive. Currently, the most common in Russia are submersible electric motors of the PED brands, commercially available by ALNAS OJSC (Almetyevsk, Tatarstan), ALMAZ LLC (Raduzhny, Tyumen Region) and a number of other enterprises, equipped with tread protection 1G51M, MP54, P92, P92D, GTM5LD, GZN92, etc.

Known submersible oil-filled electric motor (patent RU No. 2046508 C1, H02K 5/12, publ. 20.10.1995), which contains a cable entry and installed in the upper part of the hydraulic protection device with internal cameras. The cameras are coaxial and bounded by flanges. The wire that connects the motor winding to the cable entry is placed in the oil-filled cavity of the first inner chamber and through channels made in the flanges of the hydraulic protection device. The wire is sealed in the upper flange. In the hydraulic protection device, the shaft covers a protective cylinder, the upper end of which is fixed in the upper flange. Coaxial to the cylinder are two diaphragms, mounted on top of the upper flange, and on the bottom of the flange of the protective cylinder. The latter is fastened with the upper thrust bearing of the heel. The diaphragms, cylinder and housing together with the flanges form the above-mentioned inner chambers. The first of them includes two cavities filled with oil. The second inner chamber is limited by the inner diaphragm and the outer surface of the protective cylinder. The relief valves of the inner chambers are fixed in the central channel of the shaft. The bottom valve at the inlet and outlet of the radial chambers is connected to the first inner chamber and through the cavity between the mechanical seals in the upper flange with the second inner chamber. The upper valve is connected to the outlet of the lower valve and an external chamber filled with formation fluid.

The wire from the current lead to the motor passes through the tread plate. The specified wire passing through the entire internal cavity of the hydraulic protection, complicates the design of hydraulic protection and reduces the reliability of the nodes. The tread is on the same shaft as the engine. This installation of the tread significantly complicates the assembly and conduct of their testing, complicates the installation of the engine in the well.

A device is known for the hydraulic protection of a submersible oil-filled electric motor of a submersible pump (patent RU No. 49652 U1, H02K 5/12, H02K 5/132, F04D 13/10, publ. 27.11.2005). The hydroprotection device contains a compensator. The internal cavity of the tread and the hydraulic motor are hydraulically interconnected. The hydroprotector tread is made diaphragmless and contains a cable current lead in the lower part of the tread. The tread also includes a coupling for the tread and motor shafts, an oil-filled channel with an overflow valve located in its upper part, at least one radial and axial support. The mechanical seal of the bellows type is placed on the shaft in a cavity located between the upper and lower bearing bearings of the shaft.

The main disadvantage of this design is the difficulty in manufacturing the head of the electric motor, the inconvenience of assembling the disassembly of the nodes built into the head.

Known tread for hydraulic protection of a submersible oil-filled electric motor (patent RU No. 2099604 C1, F04D 13/10, Н02К 5/12, publ. 12/20/1997). The inventive protector contains a housing, inside of which a diaphragm is mounted on a support, first and second nipples, between which a heel assembly and upper and lower heads with flanges are placed for connection with a pump and an electric motor. A shaft with upper and lower mechanical seals, a valve and a casing having a flange and mounted on the upper seal are installed in the housing. The protector is equipped with a chipper. The first nipple and flange of the casing are made with additional matching holes for installation. The chipper is in the form of a disk and is rigidly mounted on a shaft above the casing. The opening of the casing is in communication with the annulus.

This technical solution does not completely preclude the penetration of small particles of mechanical impurities and sand into the cavity of the mechanical seal together with the formation fluid. From the practice of operating the hydraulic protector of the proposed design, the holes in the upper nipple are clogged with fine sand.

The closest in technical solution is the tread for hydraulic protection of a submersible oil-filled electric motor (patent RU No. 2199030 C2, F04D 13/10, Н02К 5/12, publ. 02.20.2003). The tread comprises a housing, a shaft with mechanical seals and thrust bearings, nipples, a heel assembly, a head with a receiving net and a base. Nipples with thrust bearings are located along the shaft between the head and the base with the formation of water lock chambers filled with motor oil. The heel assembly with the shaft support is located in the lower part of the tread and is combined with the base assembly. The system of pressure relief and gas removal is made in the form of check valves communicating with each other by means of axial holes and connecting tubes. Mechanical seals are located in the nipple zone, and the upper mechanical seal is made according to a dual scheme with an opposite arrangement of bellows. In cylindrical grooves of the head by means of brackets, a mesh is fixed to separate mechanical impurities.

This design does not exclude the penetration of small particles of mechanical impurities and sand into the cavity of the upper mechanical seals together with the formation fluid.

The objective of the invention is to increase the reliability of the hydraulic protection of a submersible motor by installing a special shield in the upper part in front of the upper mechanical seal from the effects of direct mechanical particles and channels for their removal.

This problem is solved in that in the tread for hydraulic protection of the oil-filled electric motor, the hydraulic oil pressure is changed by the hydraulic lock chambers, communicated by a system of connecting tubes and check valves, for which the nipples with thrust bearings are located along the shaft between the head and the base with the formation of hydraulic lock chambers filled with electric motor oil . The heel assembly with the shaft support is located in the lower part of the tread and is combined with the base assembly, the axial holes of the nipples being in communication with each other and with the annulus through a system of connecting tubes and non-return valves. In the area where the nipple baffles are located, the shaft is sealed with mechanical seals. A protective casing is fixed in the nipple above the upper mechanical seal, and a turbine is mounted on the shaft above it. In the head there are openings in communication with the annulus, coinciding with the axis of the openings of the turbine.

The proposed tread for hydraulic protection of a submersible oil-filled electric motor is illustrated in the drawing, which shows a General view of the proposed tread in section.

The tread for hydraulic protection of a submersible oil-filled electric motor contains a head 1, upper 2 and middle 3 nipples, bodies 4, 5, the heel body 6 and the base 7, connected in series with each other by a thread. The tread shaft 8 rotates in bearings 9 mounted in the nipples, the heel casing 6, the base 7. The axial load on the shaft is perceived by the heel assembly containing the movable heel 10 and the fixed thrust bearings 11. The hydrolock chambers 12, 13 are formed by the nipples 2, 3 and the heel casing 6 and are filled with motor oil during installation. The nipples 2, 3 have openings 14 for removing air when filling the hydraulic lock chambers 12, 13. The nipples 2, 3 with axial openings 14 and thrust bearings 9 are located along the shaft 8 in the axial direction between the head 1 and the base 7. To regulate the pressure at temperature oil expansion, as well as to remove the gases formed in it during operation of the electric motor, is a discharge system made in the form of check valves 15, 16 communicating with each other through axial holes 17, 18 and a connecting tube 19. Face seals eniya 20, 21, spaced along the shaft 8 in the nipple area 2, 3, protect gidrozatvornye chambers 12, 13 against the ingress of formation fluids along the shaft. The cavity 22 of the upper mechanical seal 20 is protected by a casing 23. In the tread head on the shaft 8, in the upper part above the casing 23, a turbine 24 is fixed.

In the process of the installation, the motor oil, increasing in volume, is displaced into the cavity of the base 7 and, passing through the openings 25, fills the chamber 13. The gas released by the oil during heating, is displaced through the holes 18, 17 and check valves 16, 15 in the annulus. At the same time, check valves 15, 16, designed for a certain operating pressure, prevent the formation fluid from entering the chambers 12, 13. The upper mechanical seal 20 operates in difficult conditions due to direct contact with the formation fluid, in which mechanical impurities are present. During rotation, the turbine 24 draws in mechanical impurities located on the surface of the casing 23 and moves the mechanical impurities through the openings 26 of the head 1 into the annulus.

The proposed tread for hydraulic protection of a submersible oil-filled electric motor differs little in manufacturability from currently commercially available manufacturers. A slight refinement in the manufacture will allow the production of a tread for hydraulic protection of a submersible oil-filled electric motor with more reliable protection of the upper mechanical seal, which will ultimately increase the overhaul period of the installations as a whole.

Claims (1)

A tread for hydraulic protection of a submersible oil-filled electric motor, comprising a housing, a shaft with mechanical seals located in the nipple zone, an oil-filled electric motor, nipples with axial holes and thrust bearings located along the shaft in the axial direction between the head and the base with the formation of hydraulic shutter chambers, a heel assembly with a shaft support located in the lower part of the tread and combined with the base unit, the head and base, characterized in that in the tread head in the upper hour The turbine is mounted on the shaft of the upper mechanical seal above the protective casing, and the head has openings in communication with the annulus coinciding with the axis of the openings of the turbine.