A metal bellows sealed cavity - sink combination submersible protector

Abstract

The utility model relates to the field of oil pumping unit protector of oil exploitation downhole motor drive discloses a kind of metal bellows sealed cavity-settling cavity combined type submersible protector, it includes first-stage metal bellows sealed cavity, first-stage settling cavity, second-stage metal bellows sealed cavity, second-stage settling cavity and high bearing multistage thrust short connection sequentially connected by connecting component along shaft integration;First-stage metal bellows sealed cavity includes stainless steel bellows etc.;First-stage settling cavity includes settling cavity lining sleeve assembly etc.;Second-stage metal bellows sealed cavity, second-stage settling cavity are respectively with first-stage metal bellows sealed cavity, first-stage settling cavity structure same;High bearing multistage thrust short connection includes thrust short connector head assembly etc.The utility model adopts metal bellows sealed cavity and settling cavity combination, cooperate high bearing multistage thrust short connection, improve the reliability of protector, applicable to high temperature well, inclined well, complex oil well medium environment and high axial thrust load downhole oil production equipment.

Description

Technical Field

[0001] This utility model relates to the field of oil pump protectors driven by downhole motors in oil extraction, and particularly to a metal bellows sealing cavity-settling cavity combined protector for submersible electric multi-stage centrifugal pumps or submersible screw pumps. Background Technology

[0002] Submersible electric multistage centrifugal pumps and submersible screw pumps are widely used in the oil extraction field. They consist of a submersible motor, a protector, a suction device, and a multistage centrifugal or screw pump. The protector plays a crucial role: first, it isolates well fluid to prevent it from entering the motor and causing insulation failure; second, it balances the pressure between the motor and the wellbore, compensating for the volume expansion and contraction of the motor oil due to temperature changes; and third, it balances the axial force from the pump end. Currently, a widely used similar protector is the bladder-settling chamber combination protector. However, because the bladder in this combination protector is made of rubber, it has the following drawbacks:

[0003] 1. The capsule has a low temperature resistance rating;

[0004] 2. The expansion and contraction of the motor oil to compensate for volume changes rely on the plastic deformation of the capsule material itself, which is prone to fatigue failure and has a short service life;

[0005] 3. Capsule materials are prone to aging in the well fluid environment and can react chemically with certain sensitive media in the well fluid (such as hydrogen sulfide gas), leading to premature capsule failure.

[0006] 4. The capsule structure is defective, and the gas inside the capsule cannot be completely expelled during the injection of motor oil, thus reducing its protective effect. Utility Model Content

[0007] To overcome the shortcomings of existing technologies, this utility model provides a combined submersible oil protection device with a metal bellows sealing cavity and a settling cavity, the technical solution of which is as follows:

[0008] A combined submersible oil protector with a metal bellows sealing cavity and a settling cavity includes, from top to bottom, a primary metal bellows sealing cavity, a primary settling cavity, a secondary metal bellows sealing cavity, a secondary settling cavity, and a high-load-bearing multi-stage thrust short connector, all integrally connected along the shaft via connecting components. The lower end of the primary metal bellows sealing cavity is connected to the primary settling cavity via threads at both ends of a first upper connector assembly. The lower end of the primary settling cavity is connected to the secondary metal bellows sealing cavity via threads at both ends of a middle connector assembly. The lower end of the secondary metal bellows sealing cavity is connected to the secondary settling cavity via threads at both ends of a second upper connector assembly. The lower end of the secondary settling cavity is connected to the high-load-bearing multi-stage thrust short connector via a base assembly using connecting screws. The lower end of the protector shaft is connected to the thrust short connector shaft via a second splined sleeve assembly. The primary metal bellows sealing cavity includes an integrated first spline sleeve assembly, a protector head assembly, a mechanical seal assembly, a plug, a lead gasket, an overflow valve, a sealing gasket, a metal bellows telescopic sealing joint, a metal bellows, a metal bellows sealing cavity inner liner assembly, a metal bellows sealing cavity shell, a protector shaft, a lower metal bellows sealing joint, an upper joint assembly, and an inner liner sealing seat; the primary settling cavity includes an integrated first upper joint assembly, an inner liner sealing seat, a settling pipe, a middle joint assembly, and a settling cavity inner liner assembly. Mechanical seal assembly and settling chamber housing; the secondary metal bellows sealing cavity and the secondary settling cavity have the same structure as the primary metal bellows sealing cavity and the primary settling cavity, respectively; the high load-bearing multi-stage thrust joint includes an integrated base assembly, adjusting shim, thrust joint assembly, first radial bearing, thrust washer, semi-ring sleeve, bushing, thrust seat bushing, thrust plate, thrust bearing, thrust bearing support, support seat assembly, second radial bearing, clamping tube, thrust joint housing, thrust joint base assembly, thrust joint shaft and spline sleeve assembly.

[0009] Furthermore, the protector head assembly has a first vent hole; the protector head assembly and the metal bellows sealing cavity housing are sealed with a first O-ring; the inner cylindrical surface of the metal bellows telescopic sealing joint mates with the inner bushing assembly of the metal bellows sealing cavity, and the mating surface is sealed with a third O-ring.

[0010] Furthermore, the outer cylindrical surface of the inner bushing sealing seat mates with the protector head assembly, and the mating surface is sealed by the fifth O-ring; its inner cylindrical surface mates with the inner bushing assembly of the metal bellows sealing cavity, and the mating surface is sealed by the second O-ring.

[0011] Furthermore, the top of the metal bellows telescopic sealing joint is equipped with an overflow valve, which includes a retaining ring, a valve seat, a valve core, a spring, a seventh O-ring, and a valve body; the metal bellows is made of stainless steel.

[0012] Furthermore, the lower sealing joint of the metal bellows is connected to the first upper joint assembly by a cylindrical screw, and the mating cylindrical surface between the lower sealing joint of the metal bellows and the first upper joint assembly is sealed by a fourth O-ring; the inner bushing assembly of the metal bellows sealing cavity has a first oil injection hole, and an anti-rotation pin is placed at its lower part.

[0013] Furthermore, the first upper connector assembly has a second oil injection hole and a second breather hole, the second breather hole being connected to the settling pipe.

[0014] Furthermore, the upper and lower ends of the settling chamber inner bushing assembly are equipped with second O-rings, and anti-rotation pins are placed at the lower part of the bushing assembly; the middle joint assembly has a third oil injection hole.

[0015] Furthermore, the base assembly is equipped with an oil injection valve assembly; a disc spring is installed at the lower part of the thrust bearing support.

[0016] Furthermore, the thrust shorting shaft has a semi-annular groove, in which two adjusting semi-rings are installed. The number of semi-annular grooves is the same as the number of stages of the thrust bearing. The number of stages of the thrust bearing can be increased or decreased according to the magnitude of the axial force.

[0017] Furthermore, the high-load-bearing multi-stage thrust joint also includes a sixth O-ring for sealing between the base assembly and the thrust joint assembly, a connecting screw for connecting the base assembly and the thrust joint assembly, and a first key, a second key, and a third key are installed on the thrust joint shaft.

[0018] Compared with the prior art, the present invention has the following main advantages:

[0019] 1. This utility model uses a metal bellows sealing cavity structure to replace the existing capsule sealing cavity structure, increasing the temperature resistance from the original 204℃ to over 315℃. This greatly expands its temperature adaptability range.

[0020] 2. This utility model uses a metal bellows sealing cavity structure to replace the existing capsule sealing cavity structure, which eliminates the problems of material aging and chemical reaction with well fluid, and improves its adaptability to complex well conditions.

[0021] 3. This utility model uses a metal bellows sealing cavity structure to replace the existing capsule sealing cavity structure. The compensation for the volume expansion and contraction of motor oil caused by temperature changes does not rely on the elastic deformation of the material itself, but on the axial expansion and contraction of the metal bellows. This greatly reduces the fatigue damage of alternating stress to the material and improves the reliability of the protector.

[0022] 4. This utility model uses a metal bellows sealing cavity structure to replace the existing capsule sealing cavity structure. An overflow valve is installed at the top of the bellows telescopic sealing joint. During the oil injection process, the gas inside the bellows can be completely discharged through the overflow valve, and there is no defect that the capsule structure cannot completely discharge its internal gas during the oil injection process.

[0023] 5. This utility model adopts a high-load-bearing multi-stage thrust short-connection structure, which is applicable to downhole oil production equipment such as submersible electric centrifugal pumps and submersible electric screw pumps with high axial thrust loads. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall layout structure of this utility model;

[0025] Figure 1 (1) is Figure 1 Enlarged structural diagram of Part 1 from top to bottom;

[0026] Figure 1 (2) for Figure 1 Enlarged structural diagram of Part 2 from top to bottom;

[0027] Figure 2 for Figure 1 A magnified view of part A;

[0028] Figure 3 for Figure 1 BB bellows sealing cavity cross section view

[0029] Figure 4 for Figure 1 Cross-sectional view of CC settling chamber

[0030] In the diagram: 1-First spline sleeve assembly, 2-Protector head assembly, 3-Mechanical seal assembly, 4-Plug, 5-Lead gasket, 6-First O-ring, 7-Second O-ring, 8-Relief valve, 8.1-Retaining ring, 8.2-Valve seat, 8.3-Valve core, 8.4-Spring, 8.5-Seventh O-ring, 8.6-Valve body. 9-Sealing gasket, 10-Metal bellows telescopic sealing joint, 11-Third O-ring, 12-Metal bellows, 13-Metal bellows sealing cavity inner bushing assembly, 14-Metal bellows sealing cavity housing, 15-Protector shaft, 16-Cylindrical screw, 17-Metal bellows lower sealing joint, 18-Fourth O-ring, 19-First oil injection hole, 20-Anti-rotation pin, 21-Second oil injection hole, 22-First upper joint assembly, 23-Fifth O-ring, 24-Inner bushing sealing seat, 25-Second breather hole, 26-Settling pipe, 27-Middle joint assembly, 28-Third oil injection hole, 29-Settling cavity inner bushing assembly, 30-Anti-rotation pin, 31-Base assembly, 32-Oil injection valve assembly, 33-Connecting screw, 34-Adjusting shim, 35-Sixth O-ring, 36-Thrust short joint assembly, 37-First radial Bearing, 38-First square key, 39-Thrust washer, 40-Half-ring sleeve, 41-Adjusting two half-rings, 42-Two half-rings, 43-Bushing, 44-Second square key, 45-Thrust seat bushing, 46-Thrust plate, 47-Thrust bearing, 48-Thrust bearing support, 49-Palm spring, 50-Support assembly, 51-Second radial bearing, 52-Third square key, 53-Pressure tube, 54-Thrust 55-Thrust shorting housing, 56-Thrust shorting base assembly, 57-Settling chamber housing, 58-First vent, 59-First-stage metal bellows sealing chamber, 59(A)-Second-stage metal bellows sealing chamber, 60-First-stage settling chamber, 60(A)-Second-stage settling chamber, 61-Semi-annular groove, 62-Second upper connector assembly, 63-Second spline sleeve assembly, 64-High load-bearing multi-stage thrust shorting. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. Example 1

[0032] See Figure 1 , Figure 1 (1) Figure 1 (2) Figure 2 , Figure 3 and Figure 4A combined submersible oil protector with a metal bellows sealing cavity and a settling cavity includes a primary metal bellows sealing cavity 59, a primary settling cavity 60, a secondary metal bellows sealing cavity 59(A), a secondary settling cavity 60(A), and a high-load-bearing multi-stage thrust short connector 64, which are integrally connected from top to bottom along the shaft through connecting components. The lower end of the primary metal bellows sealing cavity 59 is connected to the primary settling cavity 60 through the threads at both ends of the first upper connector assembly 22. The lower end of the primary settling cavity 60 is connected to the secondary metal bellows sealing cavity 59(A) through the threads at both ends of the middle connector assembly 27. The lower end of the secondary metal bellows sealing cavity 59(A) is connected to the secondary settling cavity 60(A) through the threads at both ends of the second upper connector assembly 62. The lower end of the secondary settling cavity 60(A) is connected to the high load-bearing multi-stage thrust short connector 64 through the base assembly 31 with connecting screws 33. The primary metal bellows sealing cavity 59, the primary settling cavity 60, the secondary metal bellows sealing cavity 59(A), and the secondary settling cavity 60(A) share the same protector shaft 15. The lower end of the protector shaft 15 is connected to the thrust short connector shaft 56 through the second spline sleeve assembly 63.

[0033] The primary metal bellows sealing cavity 59 includes an integrated first spline sleeve assembly 1, a protector head assembly 2, a mechanical seal assembly 3, a plug 4, a lead gasket 5, an overflow valve 8, a sealing gasket 9, a metal bellows telescopic sealing joint 10, a metal bellows 12, a metal bellows sealing cavity inner bushing assembly 13, a metal bellows sealing cavity housing 14, a protector shaft 15, a metal bellows lower sealing joint 17, a first upper joint assembly 22, and an inner bushing sealing seat 24. The upper and lower ends of the metal bellows sealing cavity shell 14 are connected to the protector head assembly 2 and the first upper connector assembly 22 respectively by threads. The upper part of the metal bellows sealing cavity inner bushing assembly 13 is engaged with the inner bushing sealing seat 24, and the outer circle of the upper part of the inner bushing sealing seat 24 is engaged with the protector head assembly 2. The lower part of the metal bellows sealing cavity inner bushing assembly 13 is engaged with the first upper connector assembly 22. The upper part of the metal bellows 12 is welded to the metal bellows telescopic sealing joint 10. The metal bellows telescopic sealing joint 10 can slide axially along the metal bellows sealing cavity inner bushing assembly 13. The lower part of the metal bellows 12 is welded to the metal bellows lower sealing joint 17. The metal bellows lower sealing joint 17 is fixed to the upper end of the first upper connector assembly 22 by cylindrical screws 16.

[0034] The primary settling chamber 60 includes an integrated first upper connector assembly 22, an inner liner sealing seat 24, a settling pipe 26, a middle connector assembly 27, a settling chamber inner liner assembly 29, a mechanical seal assembly 3, and a settling chamber shell 57. The upper and lower ends of the settling chamber shell 57 are connected to the first upper connector assembly 22 and the middle connector assembly 27 respectively via threads. The upper end of the settling pipe 26 is welded to the first upper connector assembly 22. The upper end of the settling chamber inner liner assembly 29 mates with the inner liner sealing seat 24, the outer circle of the inner liner sealing seat 24 mates with the first upper connector assembly 22, and the lower end of the settling chamber inner liner assembly 29 mates with the middle connector assembly 27.

[0035] The secondary metal bellows sealing cavity 59(A) and the secondary settling cavity 60(A) have the same structure as the primary metal bellows sealing cavity 59 and the primary settling cavity 60, respectively.

[0036] The high-load-bearing multi-stage thrust coupling 64 includes an integrated base assembly 31, an adjusting shim 34, a thrust coupling assembly 36, a first radial bearing 37, a thrust washer 39, a semi-ring 40, a bushing 43, a thrust seat bushing 45, a thrust plate 46, a thrust bearing 47, a thrust bearing support 48, a support assembly 50, a second radial bearing 51, a clamping tube 53, a thrust coupling housing 54, a thrust coupling base assembly 55, a thrust coupling shaft 56, and a spline sleeve assembly 1. The upper and lower ends of the thrust shorting housing 54 are connected to the thrust shorting head assembly 36 and the thrust shorting base assembly 55 respectively by threads. The bushing 43, the thrust seat bushing 45, the disc spring 50, and the clamping tube 53 are placed inside the thrust shorting housing 54 and locked by the thrust shorting head assembly 36 and the thrust shorting base assembly 55. The first radial bearing 37, the semi-ring 40, and the thrust plate 46 are fixed on the thrust shorting shaft 56 by the first square key 38, the second square key 44, and the third square key 52. ​​The thrust bearing 47, the thrust bearing support 8, and the disc spring 49 are sequentially placed on the upper part of the support base assembly 50. Example 2

[0037] See Figure 1 , Figure 1 (1) Figure 1 (2) Figure 2 , Figure 3 and Figure 4 A combined submersible oil protector with a metal bellows sealing cavity and a settling cavity, based on the technical solution described in Example 1, has a first vent 58 on the protector head assembly 2; the protector head assembly 2 and the metal bellows sealing cavity shell 14 are sealed by a first O-ring 6; the inner cylindrical surface of the metal bellows telescopic sealing joint 10 mates with the inner bushing assembly 13 of the metal bellows sealing cavity, and the mating surface is sealed by a third O-ring 11. Example 3

[0038] See Figure 1 , Figure 1 (1) Figure 1 (2) Figure 2 , Figure 3 and Figure 4 A metal bellows sealing cavity-settling cavity combined submersible oil protector, based on the technical solution described in Example 1, wherein the outer cylindrical surface of the inner bushing sealing seat 24 mates with the protector head assembly 2, and the mating surface is sealed by the fifth O-ring 23; its inner cylindrical surface mates with the inner bushing assembly 13 of the metal bellows sealing cavity, and the mating surface is sealed by the second O-ring 7. Example 4

[0039] See Figure 1 , Figure 1 (1) Figure 1 (2) Figure 2 , Figure 3 and Figure 4 A combined submersible oil protector with a metal bellows sealing cavity and a settling cavity, based on the technical solution described in Example 1, has an overflow valve 8 installed at the top of the metal bellows telescopic sealing joint 10. The overflow valve 8 includes a retaining ring 8.1, a valve seat 8.2, a valve core 8.3, a spring 8.4, a seventh O-ring 8.5, and a valve body 8.6. The metal bellows 12 is made of stainless steel, preferably 316 stainless steel or other stainless steel with similar properties. The lower sealing joint 17 of the metal bellows is connected to the first upper joint assembly 22 by a cylindrical screw 16. The mating cylindrical surfaces between the lower sealing joint 17 and the first upper joint assembly 22 are sealed by a fourth O-ring 18. The inner bushing assembly 13 of the metal bellows sealing cavity has a first oil injection hole 19, and an anti-rotation pin 20 is placed at its lower part. Example 5

[0040] See Figure 1 , Figure 1 (1) Figure 1 (2) Figure 2 , Figure 3 and Figure 4 A metal bellows-sealed cavity-settling cavity combined submersible protector, based on the technical solution described in Example 1, has a second oil injection hole 21 and a second breather hole 25 on the first upper connector assembly 22, and the second breather hole 25 communicates with the settling pipe 26. Example 6

[0041] See Figure 1 , Figure 1 (1) Figure 1 (2) Figure 2 , Figure 3 and Figure 4A metal bellows-sealed cavity-settling cavity combined submersible oil protector, based on the technical solution described in Example 1, has a second O-ring 7 installed at both the upper and lower ends of the settling cavity inner bushing assembly 29, with an anti-rotation pin 30 placed at its lower part; the middle joint assembly 27 has a third oil injection hole 28. Example 7

[0042] See Figure 1 , Figure 1 (1) Figure 1 (2) Figure 2 , Figure 3 and Figure 4 A metal bellows-sealed cavity-settling cavity combined submersible oil protector, based on the technical solution described in Example 1, has an oil injection valve assembly 32 installed on the base assembly 31; a butterfly spring 49 is installed on the lower part of the thrust bearing support 48; a semi-annular groove 61 is opened on the thrust shorting shaft 56, and two adjusting semi-rings 41 and two semi-rings 42 are installed in the semi-annular groove 61. The number of semi-annular grooves 61 is the same as the number of stages of the thrust bearing 47; the number of stages of the thrust bearing 47 can be increased or decreased according to the magnitude of the axial force. Example 8

[0043] See Figure 1 , Figure 1 (1) Figure 1 (2) Figure 2 , Figure 3 and Figure 4 A metal bellows sealing cavity-settling cavity combined submersible oil protector, based on the technical solution described in Embodiment 1, further includes a sixth O-ring 35 for sealing between the base assembly 31 and the thrust short joint assembly 36, a connecting screw 33 for connecting the base assembly 31 and the thrust short joint assembly 36, and a first square key 38, a second square key 44, and a third square key 52 installed on the thrust short joint shaft 56.

[0044] To enable those skilled in the art to better understand this utility model, the basic working principle of this utility model is briefly described below:

[0045] During operation, the axial force from the pump end is transmitted from top to bottom to the thrust shorting shaft 56 via the protector shaft 15, adjusting shim 34, and first spline sleeve assembly 1. The thrust shorting shaft 56 then transmits the axial force to the thrust bearing 47 via the adjusting half-rings 41, two half-rings 42, and thrust plate 46 installed in its semi-annular groove 61, thereby achieving axial force balance. The mechanical seal assembly 3, overflow valve 8, sealing gasket 9, metal bellows expansion joint 10, third O-ring 11, metal bellows 12, metal bellows lower sealing joint 17, and fourth O-ring 18 isolate the wellbore medium from the motor oil inside the metal bellows sealing cavity 59, preventing well fluid from entering the protector and motor. When the motor oil inside the protector and motor expands due to increased temperature, the metal bellows expansion joint 10 slides upward along the inner bushing assembly 13 of the metal bellows sealing cavity, and the internal volume of the metal bellows 12 also expands accordingly. When the motor oil inside the protector and motor contracts due to decreased temperature, the metal bellows expansion joint 10 slides downward along the inner bushing assembly 13 of the metal bellows sealing cavity, and the internal volume of the metal bellows 12 also shrinks accordingly, thereby compensating for the volume change of the motor oil caused by temperature changes.

Claims

1. A combined submersible oil protection device with a metal bellows sealing cavity and a settling cavity, characterized in that, The system comprises, from top to bottom along the axis, an integrally connected primary metal bellows sealing cavity, a primary settling cavity, a secondary metal bellows sealing cavity, a secondary settling cavity, and a high-load-bearing multi-stage thrust joint. The primary metal bellows sealing cavity includes an integrally installed first spline sleeve assembly, a protector head assembly, a mechanical seal assembly, a plug, a lead gasket, an overflow valve, a sealing gasket, a metal bellows expansion joint, a metal bellows, a metal bellows sealing cavity inner liner assembly, a metal bellows sealing cavity shell, a protector shaft, a lower metal bellows sealing joint, a first upper joint assembly, and an inner liner sealing seat. The primary settling cavity includes an integrally installed... The first upper joint assembly, inner bushing sealing seat, settling pipe, middle joint assembly, settling chamber inner bushing assembly, mechanical seal assembly, and settling chamber shell; the secondary metal bellows sealing cavity and secondary settling cavity have the same structure as the primary metal bellows sealing cavity and primary settling cavity, respectively; the high load-bearing multi-stage thrust short joint includes an integrated base assembly, adjusting shim, thrust short joint assembly, first radial bearing, thrust washer, semi-ring sleeve, bushing, thrust seat bushing, thrust plate, thrust bearing, thrust bearing support, support seat assembly, second radial bearing, clamping pipe, thrust short joint shell, thrust short joint base assembly, thrust short joint shaft, and spline sleeve assembly.

2. The combined submersible oil protection device with metal bellows sealing cavity and settling cavity according to claim 1, characterized in that, The protector head assembly has a first vent hole; the protector head assembly and the metal bellows sealing cavity housing are sealed with a first O-ring; the inner cylindrical surface of the metal bellows telescopic sealing joint mates with the inner bushing assembly of the metal bellows sealing cavity, and the mating surface is sealed with a third O-ring.

3. The combined submersible oil protection device with metal bellows sealing cavity and settling cavity according to claim 1, characterized in that, The outer cylindrical surface of the inner bushing sealing seat mates with the head assembly of the protector, and the mating surface is sealed by the fifth O-ring; its inner cylindrical surface mates with the inner bushing assembly of the metal bellows sealing cavity, and the mating surface is sealed by the second O-ring.

4. The combined submersible oil protection device with metal bellows sealing cavity and settling cavity according to claim 1, characterized in that, The top of the metal bellows telescopic sealing joint is equipped with an overflow valve, which includes a retaining ring, valve seat, valve core, spring, seventh O ring and valve body; the metal bellows is made of stainless steel.

5. The combined submersible oil protection device with metal bellows sealing cavity and settling cavity according to claim 1, characterized in that, The lower sealing joint of the metal bellows is connected to the first upper joint assembly by a cylindrical screw. The mating cylindrical surface between the lower sealing joint of the metal bellows and the first upper joint assembly is sealed by a fourth O-ring. The inner bushing assembly of the metal bellows sealing cavity has a first oil injection hole, and an anti-rotation pin is placed at its lower part.

6. The combined submersible oil protection device with metal bellows sealing cavity and settling cavity according to claim 1, characterized in that, The first upper connector assembly has a second oil injection hole and a second breather hole, and the second breather hole is connected to the settling pipe.

7. The combined submersible oil protection device with metal bellows sealing cavity and settling cavity according to claim 1, characterized in that, The settling chamber inner bushing assembly is equipped with a second O-ring at both the upper and lower ends, and an anti-rotation pin is placed at the lower part of the bushing; the middle joint assembly has a third oil injection hole.

8. The combined submersible oil protection device with metal bellows sealing cavity and settling cavity according to claim 1, characterized in that, The base assembly is equipped with an oil injection valve assembly; a disc spring is installed at the lower part of the thrust bearing support.

9. The combined submersible oil protection device with metal bellows sealing cavity and settling cavity according to claim 1, characterized in that, The thrust shorting shaft has a semi-annular groove, in which two adjusting semi-rings are installed. The number of semi-annular grooves is the same as the number of stages of the thrust bearing. The number of stages of the thrust bearing can be increased or decreased according to the magnitude of the axial force.

10. The combined submersible oil protection device of metal bellows sealing cavity and settling cavity according to claim 1, characterized in that, The high-load multi-stage thrust joint also includes a sixth O-ring for sealing between the base assembly and the thrust joint assembly, and connecting screws for connecting the base assembly and the thrust joint assembly. A first key, a second key, and a third key are installed on the thrust joint shaft.

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