CN109412310B - Cylinder type oil-submersible linear motor protector - Google Patents

Abstract

A cylindrical oil submersible linear motor protector, the protector includes a stator adapter (1), an outer protective tube (2), a metal bladder unit (3), an intermediate adapter (4), a lower adapter (6) and an inner The protective tube (7) is constituted; the specific advantages are as follows: 1) The protector of the present invention is placed on the stator side of the motor, and the expansion and contraction frequency of the metal bag of the protector has nothing to do with the movement frequency of the motor mover, but is in a peristaltic state, and the protector has a long life. ;2) The protector is composed of two sets of main and auxiliary, supplemented by an oil separator to further prolong the life of the system; 3) This protector is a self-contained system and can be pre-filled with oil, which solves the problem that the traditional linear submersible motor system must The oil motor and the protector are installed together and filled with oil uniformly.

Description

Cylinder type submersible linear motor protector

Technical Field: The present invention belongs to a sealing protection device for an underground oil submersible motor, in particular to a cylindrical submersible linear motor protector.

Background Art: Linear reciprocating submersible oil pump is an important underground crude oil production equipment, mainly including cylindrical submersible linear motor, seal protector, plunger pump and so on. The purpose of the seal protector is to balance the pressure inside and outside the cylindrical linear motor cavity, to compensate the expansion or contraction of the motor oil in the motor cavity due to temperature changes through its own expansion or contraction, and to isolate the motor in the motor cavity. Oil and well fluid, to ensure the insulation of the motor windings, thereby ensuring the safe operation of the linear reciprocating oil pump. Publication number CN 104319932A proposes a hose-type electric submersible linear motor breathing protector, in which the mover of the motor is also sealed in the protector. Due to the high-frequency reciprocating motion of the motor mover, the protector expands and contracts at high frequency. Greatly reduces the life of the linear reciprocating submersible pump. If a cylindrical submersible linear motor protector that is not affected by the movement of the mover can be invented, it will certainly increase the life of the motor, which has not been reported so far.

Invention content:

The purpose of the invention: to provide a hollow metal bellows protector for a cylindrical oil-submersible linear motor, the purpose of which is to solve the problems existing in the past. The protector is connected with the motor stator and balances the inner cavity of the cylindrical linear motor stator. , external pressure, compensate the expansion and contraction of the motor oil in the inner cavity of the motor stator, isolate the motor oil and well fluid in the inner cavity of the motor stator, solve the low pressure resistance of the cylindrical submersible linear motor, or overcome the existing submersible linear motor The short life of the motor protector is insufficient.

Technical scheme: The present invention is realized through the following technical scheme:

A cylindrical submersible linear motor protector, characterized in that the protector comprises a stator adapter (1), an outer protective tube (2), a metal bag unit (3), an intermediate adapter (4), a lower rotation The joint (6) is formed with the inner protective pipe (7); the inner protective pipe (7) is arranged in the outer protective pipe (2) to form a set of protective pipes, and there is a space between the inner protective pipe (7) and the outer protective pipe (2). The gap is used as a cavity; there are two sets of protective tubes, which are an upper protective tube and a lower protective tube. The upper protective tube and the lower protective tube are connected by an intermediate adapter (4), and the upper end of the upper protective tube is connected to the stator adapter (1). , the lower end of the lower protective tube is connected to the lower adapter (6); (that is, the stator adapter (1) is connected to the upper end of the upper protective pipe, the lower end of the upper protective pipe is connected to the intermediate adapter (4), and the intermediate adapter (4) is connected to the lower protective pipe The upper end and the lower end of the lower protective tube are connected to the lower adapter (6)!)

The stator adapter (1), the outer protective pipe (2) of the upper protective pipe, the intermediate adapter (4), and the inner protective pipe (7) of the upper protective pipe are surrounded to form an upper cavity (9), and a metal bag unit (3) ) is placed in the upper cavity (9) to form the main protector;

The middle adapter (4), the outer protective pipe (2) of the lower protective pipe, the lower adapter (6), and the inner protective pipe (7) of the lower protective pipe are surrounded to form a lower cavity (10), and the oil separator (5) and another metal bag unit (3) is arranged in the lower cavity (10) to form a secondary protector;

The upper cavity (9) and the lower cavity (10) are communicated through the intermediate oil passage (15) in the intermediate adapter (4); the assembled motor protector (without injecting motor oil) can withstand the pressure of 0.5MPa for a long time , there will be no pressure relief.

The lower end of the stator adapter (1) extends between the outer protective pipe (2) of the upper protective pipe and the inner protective pipe (7) of the upper protective pipe, and the stator adapter (1) and the outer protective pipe (2) of the upper protective pipe ) and between the stator adapter (1) and the inner protective tube (7) of the upper protective tube are provided with a rubber sealing ring (8);

The upper end of the intermediate adapter (4) extends between the outer protective pipe (2) of the upper protective pipe and the inner protective pipe (7) of the upper protective pipe, and the intermediate adapter (4) is connected to the outer protective pipe (2) of the protective pipe. A rubber sealing ring (8) is provided between and between the intermediate adapter (4) and the inner protective pipe (7) of the upper protective pipe; the lower end of the intermediate adapter (4) extends into the outer protective pipe ( 2) and the inner protective pipe (7) of the lower protective pipe, between the intermediate adapter (4) and the outer protective pipe (2) of the lower protective pipe, and between the intermediate adapter (4) and the inner protective pipe of the lower protective pipe A rubber sealing ring (8) is arranged between (7);

The upper end of the lower adapter (6) extends between the outer protective pipe (2) of the lower protective pipe and the inner protective pipe (7) of the lower protective pipe, and the lower adapter (6) is connected to the outer protective pipe (2) of the lower protective pipe. ) and between the lower adapter (6) and the inner protection tube (7) of the lower protection tube are provided with rubber sealing rings (8).

A gate valve (11) is installed on the stator adapter (1), a motor side oil passage (12) is opened in the middle part of the side wall of the stator adapter (1), and between the motor side oil passage (12) and the upper cavity (9) A gate valve (11) for blocking and opening the motor side oil passage (12) is provided on the motor side oil passage (12), the gate valve (11) is opened, the motor side oil passage (12) and the upper cavity (9) connected, the gate valve (11) is closed, and the oil passage (12) on the motor side and the upper cavity (9) are closed;

The gate valve (11) is a rotatable structure whose axial direction is perpendicular to the axial direction of the motor side oil passage (12). The axial direction of 11) is vertical, and the position of the oil drain hole (13) corresponds to the position of the oil passage (12) on the motor side, that is, when the oil drain hole (13) on the gate valve (11) rotates to the same position as the oil passage (12) on the motor side. ) is aligned (the axial direction of the oil drain hole (13) coincides with or is parallel to the axial direction of the motor side oil passage (12)), the motor side oil passage (12) communicates with the upper cavity (9), and the linear motor is protected. The motor oil in the generator and the motor oil in the stator of the cylindrical submersible linear motor communicate with each other. When the oil drain hole (13) on the gate valve (11) rotates to 90° with the oil passage (12) on the motor side , it blocks the motor oil flow between the linear motor protector and the cylindrical submersible linear motor stator (that is, the axial direction of the oil drain hole (13) is perpendicular to the axial direction of the motor side oil passage (12), and the gate valve (11) The structure of ) is the same as the principle of the ball valve in the field of water supply, and will not be repeated here);

The metal capsule unit (3) includes a seat (20), an inner metal corrugated capsule (21), an outer metal corrugated capsule (22), and a base (23) (the inner metal corrugated capsule (21) and the outer metal corrugated capsule (22) are optional. Telescopic metal bellows!), the inner metal bellows (21) is arranged inside the outer metal bellows (22) (the inner metal bellows (21) is sheathed outside the inner protective tube (7)) and the inner metal bellows (21) and A capsule cavity (17) of the corrugated capsule is formed between the outer metal corrugated capsules (22); the upper ends of the inner metal corrugated capsule (21) and the outer metal corrugated capsule (22) are both connected to the base (23), and the inner metal corrugated capsule (22) is connected to the base (23). 21) and the lower ends of the outer metal corrugated bladder (22) are both connected to the connecting seat (20), and the connecting seat (20) is provided with a liquid throughput hole (27) that communicates with the bladder cavity (17).

Guide balls (24) are installed on the base (23), and the guide balls (24) that can only roll are arranged between the base (23) and the inner wall of the outer protective pipe (2) and between the base (23) and the inner protective pipe (7). ) between the outer walls. Ensure that the base (23) moves freely between the outer protective tube (2) and the protective tube (7). The base (23) is provided with a groove for accommodating the guide ball (24). The cover plate (25), that is to say, the guide ball (24) in the metal bag unit (3) is placed between the base (23) and the base cover (25), and can roll freely. 26) Fix the base (23) and the base cover (25) together; the guide ball (24) rolls freely with the outer protective tube (2) and the inner protective tube (7), which plays the role of guiding and reducing friction.

The upper end of the metal bag unit (3) in the lower cavity (10) is provided with an oil separator ring (5), the oil separator ring (5) is composed of a ring body (28) and an oil scraper ring (29), and the oil scraper ring ( 29) both the outer and inner side walls are provided with an oil scraper ring (29), (that is, the oil scraper ring (29) is dynamically sealed between the ring body (28) and the inner wall of the outer protective tube (2) and Between the ring body (28) and the outer wall of the inner protection tube (7), it can move axially along the inner protection tube (7),)

The ring body (28) is provided with a groove, and the oil scraper ring (29) is placed in the groove of the ring body (28); after the metal bag unit (3) in the lower cavity (10) fails, the oil separator ( 5) Become a barrier to effectively isolate the failed protector.

The intermediate adapter (4) has a tubular structure, a linear sliding bearing (14) is arranged at the inner circle of the intermediate adapter (4), and an intermediate oil passage (15) and a breathing hole ( 16) (The breathing hole (16) is connected to the outside of the intermediate adapter (4)!), the breathing hole (16) and the bladder cavity (17) of the metal bladder unit (3) in the upper cavity (9) pass through the well fluid. The holes (27) are communicated;

An oil filling valve (18) and an oil drain valve (19) are installed on the lower adapter (6). Inject motor oil into the lower chamber (10) and upper chamber (9) of the protector. If the pressure in the upper and lower chambers of the protector is too large, drain the oil through the drain valve (19) to release the pressure, and the lower adapter (6) ) is also a tubular structure, a linear sliding bearing (14) is also placed at the inner circle of the lower adapter (6), and a breathing hole (16) is also opened in the middle part of the side wall of the lower adapter (6); the breathing hole (16) It communicates with the cavity (17) of the metal bladder unit (3) in the lower cavity (10) through the well fluid huff and puff hole (27).

When the metal capsule unit (3) is connected to the intermediate adapter (4) or the lower adapter (6), the well fluid huff and puff hole (27) is connected to the breathing hole ( 16) Align and communicate to ensure reliable communication between the bladder cavity (17) and the well fluid, so as to balance the internal and external pressures in the upper cavity (9) and the lower cavity (10).

The stator adapter (1), the intermediate adapter (4) and the lower intermediate adapter (6) are all non-magnetic materials, which can be made of 304 or 316L austenitic stainless steel, and the linear sliding bearing (14) is wear-resistant and non-conductive. magnetic material.

During use, under normal working conditions, the upper cavity (9) and the lower cavity (10) of the protector are filled with motor oil, and the inner cavity (17) of the bag is filled with well fluid, which passes through the inner metal corrugated bag (21) and the outer metal The corrugated bag (22), the outer protective tube (2) and the inner protective tube (7) isolate the motor oil from the well fluid; when the internal pressure of the motor and the protector is lower than the well fluid pressure, the well fluid passes through the intermediate adapter (4). ) of the breathing hole (16) and the breathing hole (16) of the lower adapter (6) enter the well fluid huff and puff hole (27) of the metal bag unit (3), and then enter the bag cavity (17), the metal corrugated bag (21) and the outer metal corrugated bladder (22) are stretched, and the motor oil is compressed to offset the pressure of the well fluid; when the motor oil inside the motor and the protector expands, the pressure is higher than the well fluid pressure, and the inner cavity of the bladder (17) ) in the well fluid is discharged through the well fluid huff and puff hole (27) and the breathing hole (16), the metal corrugated pocket (21) and the outer metal corrugated pocket (22) shrink, the upper cavity (9) and the lower cavity (10) Increased space to accommodate excess motor oil due to expansion.

Advantage effect:

Compared with the prior art, the present invention has the following specific advantages:

1) The protector of the present invention is placed on the stator side of the motor, and the expansion and contraction frequency of the metal capsule of the protector has nothing to do with the movement frequency of the motor mover, but is only in a creeping state, and the protector has a long life; 2) The protector consists of two sets of main and auxiliary. 3) The protector is a self-contained system, which can be pre-filled with oil, which solves the problem that the traditional linear submersible motor system must be integrated with the linear submersible motor and the protector. Oil.

Description of drawings:

Fig. 1 is the structural representation of the cylinder type submersible linear motor protector of the present invention;

2 is a three-dimensional cross-sectional view of a stator adapter of the present invention;

3 is a three-dimensional cross-sectional view of an intermediate adapter of the present invention;

4 is a three-dimensional cross-sectional view of a lower adapter of the present invention;

5 is a three-dimensional cross-sectional view of the metal capsule unit of the present invention;

6 is an exploded view of the base of the metal bag unit of the present invention;

7 is a three-dimensional view of the oil trap of the present invention;

Fig. 8 is a flow chart of the expansion liquid flow of the protector of the present invention.

Description of reference numbers:

1. Stator adapter, 2. Outer protective tube, 3. Metal bladder unit, 4. Intermediate adapter, 5. Oil separator, 6. Lower adapter, 7. Inner protective tube, 8. Rubber sealing ring, 9. Upper chamber, 10. Lower chamber, 11. Gate valve, 12. Motor side oil passage, 13. Oil drain hole, 14. Linear sliding bearing, 15. Middle oil passage, 16. Breathing hole, 17. Inner cavity of bladder, 18. Oil filling valve, 19. Oil drain valve, 20. Connection seat, 21. Inner metal corrugated bag, 22. Outer metal corrugated bag, 23. Base, 24. Guide ball, 25. Base cover, 26. Bolt, 27 . Well fluid huff and puff hole, 28. Ring body, 29. Oil scraping ring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below in conjunction with the accompanying drawings:

As shown in FIG. 1 , the present invention relates to a cylindrical submersible linear motor protector, which includes a stator adapter (1), an outer protective tube (2), a metal bag unit (3), an intermediate adapter ( 4), the lower adapter (6) and the inner protection pipe (7) are formed; the inner protection pipe (7) is arranged in the outer protection pipe (2) to form a group of protection pipes, and the inner protection pipe (7) is connected with the outer protection pipe (2). There is a gap between ) as a cavity; there are two sets of protective tubes, respectively an upper protective tube and a lower protective tube, the upper protective tube and the lower protective tube are connected by an intermediate adapter (4), and the upper end of the upper protective tube is connected to the stator The adapter (1), the lower end of the lower protective pipe is connected to the lower adapter (6); (that is, the stator adapter (1) is connected to the upper end of the upper protective pipe, the lower end of the upper protective pipe is connected to the intermediate adapter (4), and the intermediate adapter (4) ) is connected to the upper end of the lower protective tube, and the lower end of the lower protective tube is connected to the lower adapter (6)!)

The stator adapter (1), the outer protective pipe (2) of the upper protective pipe, the intermediate adapter (4), and the inner protective pipe (7) of the upper protective pipe are surrounded to form an upper cavity (9), and a metal bag unit (3) ) is placed in the upper cavity (9) to form the main protector;

The middle adapter (4), the outer protective pipe (2) of the lower protective pipe, the lower adapter (6), and the inner protective pipe (7) of the lower protective pipe are surrounded to form a lower cavity (10), and the oil separator (5) and another metal bag unit (3) is arranged in the lower cavity (10) to form a secondary protector;

The upper cavity (9) and the lower cavity (10) are communicated through the intermediate oil passage (15) in the intermediate adapter (4); the assembled motor protector (without injecting motor oil) can withstand the pressure of 0.5MPa for a long time , there will be no pressure relief.

The lower end of the stator adapter (1) extends between the outer protective pipe (2) of the upper protective pipe and the inner protective pipe (7) of the upper protective pipe, and the stator adapter (1) and the outer protective pipe (2) of the upper protective pipe ) and between the stator adapter (1) and the inner protective tube (7) of the upper protective tube are provided with a rubber sealing ring (8);

The upper end of the intermediate adapter (4) extends between the outer protective pipe (2) of the upper protective pipe and the inner protective pipe (7) of the upper protective pipe, and the intermediate adapter (4) is connected to the outer protective pipe (2) of the protective pipe. A rubber sealing ring (8) is provided between and between the intermediate adapter (4) and the inner protective pipe (7) of the upper protective pipe; the lower end of the intermediate adapter (4) extends into the outer protective pipe ( 2) and the inner protective pipe (7) of the lower protective pipe, between the intermediate adapter (4) and the outer protective pipe (2) of the lower protective pipe, and between the intermediate adapter (4) and the inner protective pipe of the lower protective pipe A rubber sealing ring (8) is arranged between (7);

The upper end of the lower adapter (6) extends between the outer protective pipe (2) of the lower protective pipe and the inner protective pipe (7) of the lower protective pipe, and the lower adapter (6) is connected to the outer protective pipe (2) of the lower protective pipe. ) and between the lower adapter (6) and the inner protection tube (7) of the lower protection tube are provided with rubber sealing rings (8).

A gate valve (11) is installed on the stator adapter (1), a motor side oil passage (12) is opened in the middle part of the side wall of the stator adapter (1), and between the motor side oil passage (12) and the upper cavity (9) A gate valve (11) for blocking and opening the motor side oil passage (12) is provided on the motor side oil passage (12), the gate valve (11) is opened, the motor side oil passage (12) and the upper cavity (9) connected, the gate valve (11) is closed, and the oil passage (12) on the motor side and the upper cavity (9) are closed;

The gate valve (11) is a rotatable structure whose axial direction is perpendicular to the axial direction of the motor side oil passage (12). The axial direction of 11) is vertical, and the position of the oil drain hole (13) corresponds to the position of the oil passage (12) on the motor side, that is, when the oil drain hole (13) on the gate valve (11) rotates to the same position as the oil passage (12) on the motor side. ) is aligned (the axial direction of the oil drain hole (13) coincides with or is parallel to the axial direction of the motor side oil passage (12)), the motor side oil passage (12) communicates with the upper cavity (9), and the linear motor is protected. The motor oil in the generator and the motor oil in the stator of the cylindrical submersible linear motor communicate with each other. When the oil drain hole (13) on the gate valve (11) rotates to 90° with the oil passage (12) on the motor side , it blocks the motor oil flow between the linear motor protector and the cylindrical submersible linear motor stator (that is, the axial direction of the oil drain hole (13) is perpendicular to the axial direction of the motor side oil passage (12), and the gate valve (11) The structure of ) is the same as the principle of the ball valve in the field of water supply, and will not be repeated here);

The metal capsule unit (3) includes a seat (20), an inner metal corrugated capsule (21), an outer metal corrugated capsule (22) and a base (23), and the inner metal corrugated capsule (21) is arranged in the outer metal corrugated capsule (22) ( The inner metal corrugated bag (21) is sheathed outside the inner protective tube (7)) The inner metal corrugated bag (21) and the outer metal corrugated bag (22) form a bag cavity (17) of the corrugated bag; the inner metal corrugated bag (22) 21) and the upper ends of the outer metal corrugated bag (22) are both connected to the base (23), and the lower ends of the inner metal corrugated bag (21) and the outer metal corrugated bag (22) are both connected to the connection seat (20), and the connection seat (20) ) is provided with a liquid throughput hole (27) communicating with the bladder cavity (17).

Guide balls (24) are installed on the base (23), and the guide balls (24) that can only roll are arranged between the base (23) and the inner wall of the outer protective pipe (2) and between the base (23) and the inner protective pipe (7). ) between the outer walls. Ensure that the base (23) moves freely between the outer protective tube (2) and the protective tube (7). The base (23) is provided with a groove for accommodating the guide ball (24). The cover plate (25), that is to say, the guide ball (24) in the metal bag unit (3) is placed between the base (23) and the base cover (25), and can roll freely. 26) Fix the base (23) and the base cover (25) together; the guide ball (24) rolls freely with the outer protective tube (2) and the inner protective tube (7), which plays the role of guiding and reducing friction.

The upper end of the metal bag unit (3) in the lower cavity (10) is provided with an oil separator ring (5), the oil separator ring (5) is composed of a ring body (28) and an oil scraper ring (29), and the oil scraper ring ( 29) both the outer and inner side walls are provided with an oil scraper ring (29), (that is, the oil scraper ring (29) is dynamically sealed between the ring body (28) and the inner wall of the outer protective tube (2) and Between the ring body (28) and the outer wall of the inner protection tube (7), it can move axially along the inner protection tube (7),)

The ring body (28) is provided with a groove, and the oil scraper ring (29) is placed in the groove of the ring body (28); after the metal bag unit (3) in the lower cavity (10) fails, the oil separator ( 5) Become a barrier to effectively isolate the failed protector.

The intermediate adapter (4) has a tubular structure, a linear sliding bearing (14) is arranged at the inner circle of the intermediate adapter (4), and an intermediate oil passage (15) and a breathing hole ( 16) (The breathing hole (16) is connected to the outside of the intermediate adapter (4)!), the breathing hole (16) and the bladder cavity (17) of the metal bladder unit (3) in the upper cavity (9) pass through the well fluid. The holes (27) are communicated;

An oil filling valve (18) and an oil drain valve (19) are installed on the lower adapter (6). Inject motor oil into the lower chamber (10) and upper chamber (9) of the protector. If the pressure in the upper and lower chambers of the protector is too large, drain the oil through the drain valve (19) to release the pressure, and the lower adapter (6) ) is also a tubular structure, a linear sliding bearing (14) is also placed at the inner circle of the lower adapter (6), and a breathing hole (16) is also opened in the middle part of the side wall of the lower adapter (6); the breathing hole (16) It communicates with the cavity (17) of the metal bladder unit (3) in the lower cavity (10) through the well fluid huff and puff hole (27).

When the metal capsule unit (3) is connected to the intermediate adapter (4) or the lower adapter (6), the well fluid huff and puff hole (27) is connected to the breathing hole ( 16) Align and communicate to ensure reliable communication between the bladder cavity (17) and the well fluid, so as to balance the internal and external pressures in the upper cavity (9) and the lower cavity (10).

The stator adapter (1), the intermediate adapter (4) and the lower intermediate adapter (6) are all non-magnetic materials, which can be made of 304 or 316L austenitic stainless steel, and the linear sliding bearing (14) is wear-resistant and non-conductive. magnetic material.

During use, under normal working conditions, the upper cavity (9) and the lower cavity (10) of the protector are filled with motor oil, and the inner cavity (17) of the bag is filled with well fluid, which passes through the inner metal corrugated bag (21) and the outer metal The corrugated bag (22), the outer protective tube (2) and the inner protective tube (7) isolate the motor oil from the well fluid; when the internal pressure of the motor and the protector is lower than the well fluid pressure, the well fluid passes through the intermediate adapter (4). ) of the breathing hole (16) and the breathing hole (16) of the lower adapter (6) enter the well fluid huff and puff hole (27) of the metal bag unit (3), and then enter the bag cavity (17), the metal corrugated bag (21) and the outer metal corrugated bladder (22) are stretched, and the motor oil is compressed to offset the pressure of the well fluid; when the motor oil inside the motor and the protector expands, the pressure is higher than the well fluid pressure, and the inner cavity of the bladder (17) ) in the well fluid is discharged through the well fluid huff and puff hole (27) and the breathing hole (16), the metal corrugated pocket (21) and the outer metal corrugated pocket (22) shrink, the upper cavity (9) and the lower cavity (10) Increased space to accommodate excess motor oil due to expansion.

Claims (9)

1. The utility model provides a oily linear electric motor protector of drum formula dives which characterized in that: the protector comprises a stator adapter (1), an outer protective pipe (2), a metal bag unit (3), a middle adapter (4), a lower adapter (6) and an inner protective pipe (7); the inner protecting pipe (7) is arranged in the outer protecting pipe (2) to form a group of protecting pipes, and a gap is reserved between the inner protecting pipe (7) and the outer protecting pipe (2) to be used as a cavity; the protective pipes are divided into two groups, namely an upper protective pipe and a lower protective pipe, the upper protective pipe and the lower protective pipe are connected through a middle adapter (4), the upper end of the upper protective pipe is connected with the stator adapter (1), and the lower end of the lower protective pipe is connected with a lower adapter (6);

the stator adapter (1), the outer protecting pipe (2) of the upper protecting pipe, the middle adapter (4) and the inner protecting pipe (7) of the upper protecting pipe are enclosed to form an upper cavity (9), and a metal bag unit (3) is arranged in the upper cavity (9) to form a main protector;

the middle adapter (4), the outer protecting pipe (2) of the lower protecting pipe, the lower adapter (6) and the inner protecting pipe (7) of the lower protecting pipe are enclosed to form a lower cavity (10), and the oil-isolating ring (5) and the other metal bag unit (3) are arranged in the lower cavity (10) to form an auxiliary protector;

the upper cavity (9) is communicated with the lower cavity (10) through an intermediate oil duct (15) in the intermediate adapter (4);

a gate valve (11) for blocking and opening a motor side oil duct (12) is arranged on the stator adapter (1);

a guide ball (24) is arranged on a base (23) of the metal bag unit (3);

an oil isolating ring (5) is arranged at the upper end of the metal bag unit (3) in the lower cavity (10);

the metal bag unit (3) comprises a connecting seat (20), an inner metal corrugated bag (21), an outer metal corrugated bag (22) and a base (23), the inner metal corrugated bag (21) is arranged in the outer metal corrugated bag (22), and a bag inner cavity (17) is formed between the inner metal corrugated bag (21) and the outer metal corrugated bag (22); the upper ends of the inner metal corrugated bag (21) and the outer metal corrugated bag (22) are connected with the base (23), the lower ends of the inner metal corrugated bag (21) and the outer metal corrugated bag (22) are connected with the connecting seat (20), and the connecting seat (20) is provided with a well fluid throughput hole (27) communicated with the bag inner cavity (17);

the side wall of the middle adapter (4) is provided with the middle oil duct (15) and a breathing hole (16), and the breathing hole (16) is communicated with a bag inner cavity (17) of the metal bag unit (3) in the upper cavity (9) through the well fluid handling hole (27);

the side wall of the lower rotary joint (6) is also provided with a breathing hole (16); the lower rotary joint breathing hole (16) is communicated with a bag inner cavity (17) of the metal bag unit (3) in the lower cavity (10) through the well fluid throughput hole (27).

2. The protector for the cylindrical submersible linear motor according to claim 1, characterized in that: the lower end of the stator adapter (1) extends into a position between an outer protective pipe (2) of the upper protective pipe and an inner protective pipe (7) of the upper protective pipe, rubber sealing rings (8) are arranged between the stator adapter (1) and the outer protective pipe (2) of the upper protective pipe and between the stator adapter (1) and the inner protective pipe (7) of the upper protective pipe;

the upper end of the middle adapter (4) extends into a position between an outer protective pipe (2) of the upper protective pipe and an inner protective pipe (7) of the upper protective pipe, and rubber sealing rings (8) are arranged between the middle adapter (4) and the outer protective pipe (2) of the upper protective pipe and between the middle adapter (4) and the inner protective pipe (7) of the upper protective pipe; the lower end of the middle adapter (4) extends into a position between an outer protecting pipe (2) of the lower protecting pipe and an inner protecting pipe (7) of the lower protecting pipe, and rubber sealing rings (8) are arranged between the middle adapter (4) and the outer protecting pipe (2) of the lower protecting pipe and between the middle adapter (4) and the inner protecting pipe (7) of the lower protecting pipe;

the upper end of the lower rotary joint (6) extends into the space between the outer protecting pipe (2) of the lower protecting pipe and the inner protecting pipe (7) of the lower protecting pipe, and rubber sealing rings (8) are arranged between the lower rotary joint (6) and the outer protecting pipe (2) of the lower protecting pipe and between the lower rotary joint (6) and the inner protecting pipe (7) of the lower protecting pipe.

3. The protector for the cylindrical submersible linear motor according to claim 1, characterized in that: the motor side oil duct (12) is formed in the side wall of the stator adapter (1), the motor side oil duct (12) is connected with the upper cavity (9), and the gate valve (11) for blocking and opening the motor side oil duct (12) is arranged on the motor side oil duct (12);

the gate valve (11) is a structure which is axially vertical to the axial direction of the motor side oil duct (12) and can rotate, an oil drain hole (13) is formed in the gate valve (11), the axial direction of the oil drain hole (13) is vertical to the axial direction of the gate valve (11), the position of the oil drain hole (13) corresponds to the position of the motor side oil duct (12), namely when the oil drain hole (13) in the gate valve (11) rotates to be aligned with the motor side oil duct (12), the motor side oil duct (12) is communicated with the upper cavity (9), and when the oil drain hole (13) in the gate valve (11) rotates to be 90 degrees with the motor side oil duct (12), the oil circulation of the linear motor protector and the motor oil in the cylinder type submersible linear motor stator is blocked.

4. The protector for the cylindrical submersible linear motor according to claim 3, characterized in that: the guide balls (24) capable of rolling are arranged between the base (23) and the inner wall of the outer protection pipe (2) and between the base (23) and the outer wall of the inner protection pipe (7).

5. The protector for the cylindrical submersible linear motor according to claim 4, characterized in that: the oil separating ring (5) consists of a ring body (28) and an oil scraping ring (29), and the outer circle side wall and the inner circle side wall of the ring body (28) are both provided with the oil scraping ring (29).

6. The protector for the cylindrical submersible linear motor according to claim 5, wherein: the ring body (28) is provided with a groove, and the oil scraper ring (29) is arranged in the groove of the ring body (28).

7. The protector for the cylindrical submersible linear motor according to any one of claims 4 to 6, wherein: the middle adapter (4) is of a tubular structure, and a linear sliding bearing (14) is arranged at the inner circle of the middle adapter (4);

install oiling valve (18) and bleeder valve (19) down on connecting (6), oiling valve (18) and bleeder valve (19) all communicate with cavity (10) down, inject motor oil into cavity (10) and epicoele body (9) under to the protector through oiling valve (18), if the internal pressure of upper and lower cavity of protector is too big, release pressure through bleeder valve (19) draining, straight line slide bearing (14) have also been laid to lower round department in connecting (6).

8. The protector for the cylindrical submersible linear motor according to claim 7, wherein: the stator adapter (1), the middle adapter (4) and the lower adapter (6) are all made of non-magnetic materials, 304 or 316L austenitic stainless steel materials are adopted, and the linear sliding bearing (14) is made of wear-resistant non-magnetic materials.

9. The protector for the cylindrical submersible linear motor according to claim 7, wherein: when the protector is used, under a normal working state, the upper cavity (9) and the lower cavity (10) of the protector are filled with motor oil, well liquid is filled in the inner cavity (17) of the capsule, and the motor oil and the well liquid are separated through the inner metal corrugated capsule (21), the outer metal corrugated capsule (22), the outer protecting pipe (2) and the inner protecting pipe (7); when the internal pressure of the motor and the protector is lower than the pressure of well liquid, the well liquid enters the well liquid throughput hole (27) of the metal bag unit (3) through the breathing hole (16) of the middle adapter (4) and the breathing hole (16) of the lower adapter (6) and then enters the bag inner cavity (17), the inner metal corrugated bag (21) and the outer metal corrugated bag (22) are stretched, and the motor oil is compressed to counteract the pressure of the well liquid; when motor oil inside the motor and the protector expands, the pressure is higher than the pressure of well fluid, the well fluid in the bag inner cavity (17) is discharged through the well fluid throughput hole (27) and the breathing hole (16), the inner metal corrugated bag (21) and the outer metal corrugated bag (22) contract, and the space of the upper cavity (9) and the lower cavity (10) is increased to accommodate the extra motor oil caused by expansion.

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