A dismounting tool and method for a petroleum and natural gas drilling pump cylinder liner

Abstract

The application discloses a dismounting tool and method for a cylinder liner of an oil and gas drilling pump, relates to the dismounting of a cylinder liner of a drilling pump, and is applied to the scene where the cylinder liner and the pump body are combined through bolts; the bolt has a screw rod and a first nut, and the first nut is located between the cylinder liner and the dismounting tool; the dismounting tool comprises a cylinder body capable of being positioned and connected with the bolt, the bottom of the cylinder body is closed, a piston plate is slidably connected in the cylinder body, and a liquid oil cavity is formed between the piston plate and the bottom of the cylinder body; a liquid oil connector is arranged on the cylinder body and communicates with the liquid oil cavity; when hydraulic oil is gradually filled in the liquid oil cavity, the cylinder body can be stretched and moved with the bolt, so that the bolt is elastically deformed along the axial direction of the bolt. The application can not only quickly and conveniently dismount and install the joint, but also accurately control the pre-tightening force of the bolt for combining the cylinder liner and the pump body.

Description

A tool and method for disassembling and assembling cylinder liners of oil and gas drilling pumps. Technical Field

[0001] This invention relates to the field of disassembly and assembly of drilling pump cylinder liners, and in particular to a tool and method for disassembling and assembling cylinder liners of oil and gas drilling pumps. Background Technology

[0002] The drilling pump is a crucial component of the oil drilling rig's circulation system, responsible for circulating drilling mud and injecting cement during the drilling process. The cylinder liner is another vital part of the drilling pump; by replacing cylinder liners of different diameters, the pump's displacement and discharge pressure can be adjusted to adapt to various drilling conditions. Therefore, cylinder liner replacement is an indispensable part of the drilling process.

[0003] Traditional cylinder liners are bolted to the hydraulic cylinder via cylinder liner covers. Each bolt requires sufficient torque, necessitating the use of a lever or a hammer to strike the wrench. This method makes it difficult to effectively control the preload torque, resulting in a labor-intensive process and a high risk of personal injury. For compact drilling pumps, the small cylinder spacing, especially the bolts located in the cylinder gaps, leaves very limited room for movement. Therefore, replacing traditional cylinder liners is difficult and inefficient.

[0004] Therefore, there is a need in the field for a tool that enables quick and convenient replacement of the cylinder liners of drilling pumps. Summary of the Invention

[0005] The purpose of this invention is to provide a tool and method for disassembling and assembling cylinder liners of oil and gas drilling pumps, which can not only quickly and conveniently disassemble and install the joints, but also accurately control the preload of the bolts on the cylinder liner and pump body.

[0006] The technical solution adopted in this invention is as follows: a tool for disassembling and assembling a cylinder liner of an oil and gas drilling pump, applied to scenarios where the cylinder liner and pump body are joined by bolts; the bolt has a threaded rod and a first nut, the first nut being located between the cylinder liner and the tool; it includes a cylinder capable of being positioned and connected to the bolt, the bottom of the cylinder being closed, a piston plate being slidably connected inside the cylinder, and a hydraulic oil chamber being formed between the piston plate and the bottom of the cylinder; a hydraulic oil connector is provided on the cylinder, the hydraulic oil connector communicating with the hydraulic oil chamber; when hydraulic oil is gradually filled into the hydraulic oil chamber, the cylinder can stretch and move with the bolt, causing the bolt to undergo elastic deformation along its own axial direction.

[0007] Furthermore, a sealing ring is provided between the piston plate and the inner wall of the cylinder.

[0008] Furthermore, a connecting flange is provided at one end of the cylinder, and a connecting hole is provided on the connecting flange for bolts to pass through. The bolt thread can pass through the connecting hole and be positioned and locked by a second nut.

[0009] Furthermore, a sealing plate is provided at the other end of the cylinder, which seals the bottom of the cylinder.

[0010] Furthermore, a load-bearing connecting member is provided between the connecting flange and the sealing plate.

[0011] Furthermore, a limiting component is provided on the cylinder, and the piston plate is assembled between the limiting component and the bottom of the cylinder.

[0012] Furthermore, a handle is provided on the outer surface of the cylinder.

[0013] Furthermore, it also includes a ratchet wrench, which includes a ratchet head having a constraint hole that matches the shape of the nut in the bolt, and a lifting rod rotatably connected to the ratchet head, the position of which the ratchet head and the lifting rod are rotatably connected does not coincide with the axis of the constraint hole.

[0014] A method for disassembling and assembling a cylinder liner of an oil and gas drilling pump includes the following steps:

[0015] S1: Install cylinder liners; see steps S11-S15 for details;

[0016] S11: Use the first nut and screw to engage the cylinder liner with the pump body, completing the initial engagement;

[0017] S12: Install the disassembly and assembly tool for the oil and gas drilling pump cylinder liner; after passing the screw through the connecting hole, connect the second nut, the second nut restricting the position of the disassembly and assembly tool relative to the screw; connect the hydraulic oil connector to the hydraulic oil supply device;

[0018] S13: The hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber through the hydraulic oil connector. The hydraulic oil exists between the piston plate and the bottom of the cylinder. The hydraulic oil pushes the piston plate against the cylinder liner or pump body. The cylinder liner or pump body restricts the movement of the piston plate. The hydraulic oil reacts to the bottom of the cylinder, and the cylinder, along with the screw, performs a tensile motion along the screw axis. The screw undergoes elastic deformation and has elastic force. The first nut follows the screw away from the engagement position.

[0019] S14: Tighten the first nut, and the first nut will return to the engaged position, completing the engagement again;

[0020] S15: Remove the hydraulic oil. The elastic deformation of the screw cannot be recovered due to the presence of the first nut. The elastic energy generated by the elastic deformation of the screw is transmitted between the cylinder liner and the pump body through the first nut, forming a preload force between the cylinder liner and the pump body; the installation of the cylinder liner is completed.

[0021] S2: Remove the cylinder liner; see steps S21-S25 for details;

[0022] S21: Use the disassembly and assembly tools for installing the oil and gas drilling pump cylinder liner described in steps S11-12;

[0023] S22: The hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber through the hydraulic oil connector. The hydraulic oil exists between the piston plate and the bottom of the cylinder. The hydraulic oil pushes the piston plate against the cylinder liner or pump body. The cylinder liner or pump body restricts the movement of the piston plate. The hydraulic oil reacts to the bottom of the cylinder. The pressure of the hydraulic oil overcomes the preload force between the cylinder liner and the pump body held by the first nut.

[0024] S23: Tighten the first nut until it is out of the engagement position; until the hydraulic oil is drained, there is no preload between the cylinder liner and the pump body;

[0025] S24: Continue to tighten the first nut to complete the cylinder liner removal.

[0026] Furthermore, if a preload is required between the cylinder liner and the pump body, the preload between the cylinder liner and the pump body should be zero during the initial engagement and re-engagement in steps S11 and S14 when installing the cylinder liner.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] 1. This invention utilizes the pressure of hydraulic oil acting on the cylinder body, causing the cylinder body to move along with the screw, thereby causing the screw to undergo elastic deformation and generate elastic force. When installing the cylinder liner, this elastic force can serve as the preload force for the first nut to connect the cylinder liner to the pump body; when disassembling the cylinder liner, this elastic force can overcome the preload force of the first nut connecting the cylinder liner to the pump body, thus facilitating the tightening of the first nut and achieving the goal of quick and convenient disassembly and installation of the cylinder liner.

[0029] 2. This invention uses the elastic force generated by the screw as the preload force for the first nut to engage the cylinder liner and the pump body. The elastic force generated by the screw comes from the pressure of the hydraulic oil. This allows the preload force of the first nut to engage the cylinder liner and the pump body to be controlled by controlling the pressure of the hydraulic oil, thereby improving the reliability of the pump body operation. Attached Figure Description

[0030] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0031] Figure 1 is a cross-sectional structural diagram of the solution disclosed in this invention;

[0032] Figure 2 is a schematic diagram of the external structure of the solution disclosed in this invention;

[0033] Figure 3 is a schematic diagram of the ratchet wrench disclosed in this invention;

[0034] Figure 4 is a schematic diagram of the use of the ratchet wrench when installing the cylinder liner according to the present invention;

[0035] The markings in the diagram are: 1-Pump body; 2-Screw; 21-First nut; 22-Second nut; 3-Cylinder liner; 31-Pressure plate; 4-Cylinder body; 41-Connecting flange; 42-Connecting piece; 43-Sealing plate; 44-Liquid chamber; 45-Limiting piece; 5-Piston plate; 51-Sealing ring; 6-Handle; 7-Liquid connector; 8-Ratchet wrench; 81-Lifting rod; 82-Ratchet head; 83-Constraint hole. Detailed Implementation

[0036] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0037] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0038] Example 1

[0039] As shown in Figures 1-4, a tool for disassembling and assembling a cylinder liner of an oil and gas drilling pump is used in scenarios where the cylinder liner 3 and the pump body 1 are connected by bolts. The bolt has a screw 2 and a first nut 21, with the first nut 21 located between the cylinder liner 3 and the tool. Specifically, the pump body 1 has an mounting position for installing the cylinder liner 3, and the cylinder liner 3 is mated to the mounting position. One end of the screw 2 is connected to the pump body 1, and the other end of the screw 2 passes through a pressure plate 31 and is threadedly connected to the first nut 21. The pressure plate 31 presses the cylinder liner 3 tightly in the mounting position, thereby connecting the cylinder liner 3 and the pump body 1 by the first nut 21 in conjunction with the screw 2.

[0040] In this embodiment, the disassembly and assembly tool includes a cylinder 4 that can be positioned and connected with the bolt, meaning that the connection position between the cylinder 4 and the screw 2 will not change throughout the entire installation process. The cylinder 4 has two ends, one of which is an open end, in a non-closed state, allowing one end of the cylinder liner 3 to enter the cylinder 4, thus avoiding positional interference of the cylinder liner 3 with the installation of the cylinder 4. The other end of the cylinder 4 is closed, serving as the bottom of the cylinder 4. A piston plate 5 is slidably connected inside the cylinder 4, and the piston plate 5 can move along the axial direction of the cylinder 4 until the piston plate 5 moves. After the piston plate 5 is restricted from moving by the end of the cylinder liner 3, the pump body 1, or the pressure plate 31, the piston plate 5 stops moving; a hydraulic oil chamber 44 is formed between the piston plate 5 and the bottom of the cylinder 4, and a hydraulic oil connector 7 is provided on the cylinder 4. The hydraulic oil connector 7 is connected to the hydraulic oil chamber 44. Hydraulic oil from the hydraulic oil connector 7 enters the hydraulic oil chamber 44, and the hydraulic oil can act on the piston plate 5 and the bottom of the cylinder 4; when hydraulic oil is gradually filled into the hydraulic oil chamber 44, the cylinder 4 can stretch and move with the bolt, so that the bolt undergoes elastic deformation along its own axial direction.

[0041] In this embodiment, the hydraulic oil connector 7 is a quick-connect connector, which can be quickly connected to the hydraulic oil supply device, which can be an oil station. The hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber 44, and the piston plate 5 and the bottom of the cylinder 4 are both subjected to the pressure of the hydraulic oil. Initially, the piston plate 5 can slide along the axis of the cylinder 4 to relieve the pressure of the hydraulic oil. Until the piston plate 5 is restricted by the end of the cylinder liner 3, the piston plate 5 cannot move. The bottom of the cylinder 4 is subjected to the action of the hydraulic oil. In addition, the connection position between the cylinder 4 and the screw 2 is fixed, that is, the pressure of the hydraulic oil pushes the cylinder 4 to elastically stretch the screw 2. The screw 2 generates elastic deformation and has elastic force. When installing the cylinder liner 3, this elastic force can be used as the pre-tightening force of the first nut 21 to close the cylinder liner 3 and the pump body 1. When disassembling the cylinder liner 3, this elastic force can overcome the pre-tightening force of the first nut 21 to close the cylinder liner 3 and the pump body 1. This achieves the purpose of conveniently turning the first nut 21, thereby realizing the purpose of quickly and conveniently disassembling and installing the cylinder liner 3.

[0042] In this embodiment, the elastic force generated by the screw 2 is used as the preload force for the first nut 21 to connect the cylinder sleeve 3 and the pump body 1. The elastic force generated by the screw 2 comes from the pressure of the hydraulic oil. This allows the pressure of the hydraulic oil to be controlled to control the preload force of the first nut 21 connecting the cylinder sleeve 3 and the pump body 1, thereby improving the reliability of the pump body 1.

[0043] Example 2

[0044] Based on Example 1, further feasible implementation methods are proposed.

[0045] In one feasible implementation, to ensure the hydraulic oil pressure in the hydraulic oil chamber 44, the hydraulic oil chamber 44 must be sealed. Therefore, a sealing ring 51 is provided between the piston plate 5 and the inner wall of the cylinder 4 to prevent hydraulic oil leakage from causing insufficient hydraulic oil pressure to stretch the screw 2 and produce elastic deformation.

[0046] In one feasible implementation, a connecting flange 41 is provided at one end of the cylinder 4. The connecting flange 41 is provided with a connecting hole for the bolt to pass through. The bolt shank 2 can pass through the connecting hole and be positioned and locked by the second nut 22. The connecting flange 41 replaces the connection between the end of the cylinder 4 and the bolt 2, ensuring that it has sufficient strength to withstand the pressure of hydraulic oil, so that it can stably carry the bolt 2 to produce elastic deformation.

[0047] In one feasible implementation, a sealing plate 43 is provided at the other end of the cylinder 4. The sealing plate 43 seals the bottom of the cylinder 4. The sealing plate 43 has higher strength than the cylinder 4. On the one hand, it ensures that the bottom of the cylinder 4 is sealed, and on the other hand, it ensures that the bottom of the cylinder 4 has sufficient strength to withstand the pressure of the hydraulic oil.

[0048] In one feasible implementation, a force-bearing connector 42 is provided between the connecting flange 41 and the sealing plate 43. The connector 42 is preferably "L" shaped, with one end connected to the connecting flange and the other end connected to the sealing plate 43. The pressure of the hydraulic oil is transmitted to the connecting flange 41 through the sealing plate 43 and the connector 42, so as to avoid the cylinder 4 itself bearing the pressure of the hydraulic oil, thereby preventing the cylinder 4 itself from being stretched.

[0049] It should be noted that the strength of the aforementioned sealing plate 43, connector 42 and connecting flange 41 should be higher than the strength of the screw 2, so as to ensure that the screw 2 is not affected by the deformation of the sealing plate 43, connector 42 and connecting flange 41 when it undergoes elastic deformation.

[0050] In one feasible implementation, a limiting member 45 is provided on the cylinder 4, and the piston plate 5 is assembled between the limiting member 45 and the bottom of the cylinder 4. The limiting member 45 is preferably a positioning screw, which limits the maximum distance between the piston plate 5 and the bottom of the cylinder 4, thereby limiting the maximum distance at which the cylinder 4 deforms with the screw 2, preventing the elastic deformation of the screw 2 from being converted into plastic deformation, and ensuring that the screw 2 can have and maintain elastic force.

[0051] In one feasible implementation, a handle 6 is provided on the outer surface of the cylinder 4 to facilitate the installation and disassembly of the disassembly tool.

[0052] Example 3

[0053] Based on any one of the implementation methods in Examples 1-2, further feasible implementation methods are proposed.

[0054] As shown in Figures 3 and 4, the disassembly and assembly tool also includes a ratchet wrench 8, which includes a ratchet head 82. The ratchet head 82 has a constraint hole 83 that matches the shape of the nut in the bolt. The nut can be a first nut 21 or a second nut 22. The first nut 21 or the second nut 22 can be placed into the constraint hole 83. The ratchet head 82 is rotatably connected to a lifting rod 81. The position where the ratchet head 82 and the lifting rod 81 are rotatably connected does not coincide with the axis of the constraint hole 83. That is, the force is transmitted through the lifting rod 81, so that the ratchet head 82 is subjected to torque and rotates, which further rotates the first nut 21 and the second nut 22.

[0055] Furthermore, the lifting rod 81 includes a handle and a connecting rod, one end of which is connected to the handle, and the other end of which is rotatably connected to the ratchet head 82 via a rotating pin.

[0056] Example 4

[0057] As shown in Figures 1-4, a method for disassembling and assembling a cylinder liner of an oil and gas drilling pump includes the following steps:

[0058] S1: Install cylinder liner 3; see steps S11-S15 for details;

[0059] S11: Use the first nut 21 in conjunction with the screw 2 to engage the cylinder liner 3 and the pump body 1 to complete the initial engagement; for the first nut 21 in the narrow space, use the ratchet wrench 8 described in Example 3 to turn it;

[0060] S12: Install the disassembly and assembly tool for the oil and gas drilling pump cylinder liner as described in any one of Embodiments 1-2; after passing the screw 2 through the connecting hole, connect the second nut 22. The second nut 22 restricts the position of the disassembly and assembly tool relative to the screw 2. For the second nut 22 in a narrow space, use the ratchet wrench 8 as described in Embodiment 3 to turn it; connect the hydraulic oil connector 7 to the hydraulic oil supply device.

[0061] S13: The hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber 44 through the hydraulic oil connector 7. The hydraulic oil exists between the piston plate 5 and the bottom of the cylinder 4. The hydraulic oil pushes the piston plate 5 to abut against the cylinder liner 3 or the pump body 1. The cylinder liner 3 or the pump body 1 restricts the movement of the piston plate 5. The hydraulic oil reacts to the bottom of the cylinder 4. The cylinder 4 carries the screw 2 and makes a stretching motion along the axis of the screw 2. The screw 2 undergoes elastic deformation and has elastic force. The first nut 21 moves away from the engagement position along with the screw 2.

[0062] S14: Tighten the first nut 21, and the first nut 21 returns to the engaged position, completing the engagement again;

[0063] S15: Remove the hydraulic oil. The elastic deformation of the screw 2 cannot be restored due to the presence of the first nut 21. The elastic energy generated by the elastic deformation of the screw 2 is transmitted between the cylinder liner 3 and the pump body 1 through the first nut 21, forming a preload force between the cylinder liner 3 and the pump body 1; the installation of the cylinder liner 3 is completed.

[0064] S2: Remove cylinder liner 3; see steps S21-S25 for details;

[0065] S21: Use the disassembly and assembly tools for the oil and gas drilling pump cylinder liner described in any one of Examples 1-2 to install the cylinder liner in steps S11-12;

[0066] S22: The hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber 44 through the hydraulic oil connector 7. The hydraulic oil exists between the piston plate 5 and the bottom of the cylinder 4. The hydraulic oil pushes the piston plate 5 to abut against the cylinder liner 3 or the pump body 1. The cylinder liner 3 or the pump body 1 restricts the movement of the piston plate 5. The hydraulic oil reacts to the bottom of the cylinder 4. The pressure of the hydraulic oil overcomes the preload force between the cylinder liner 3 and the pump body 1 held together by the first nut 21.

[0067] S23: Tighten the first nut 21, and the first nut 21 will be disengaged from the engagement position; until the hydraulic oil is removed, there is no preload between the cylinder liner 3 and the pump body 1;

[0068] S24: Continue to tighten the first nut 21 to complete the disassembly of cylinder liner 3.

[0069] Furthermore, if a preload is required between the cylinder liner 3 and the pump body 1, the preload between the cylinder liner 3 and the pump body 1 can be zero when the first nut 21 engages the cylinder liner 3 and the pump body 1 during the initial engagement and re-engagement in steps S11 and S14 during cylinder liner 3 installation.

[0070] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A tool for disassembling and assembling a cylinder liner of an oil and gas drilling pump, applied to a scenario where the cylinder liner (3) and the pump body (1) are joined by bolts; the bolt has a screw (2) and a first nut (21), the pump body (1) has an mounting position for mounting the cylinder liner (3), the cylinder liner (3) is mated to the mounting position, one end of the screw (2) is connected to the pump body (1), and the other end of the screw (2) passes through a pressure plate (31) and is threadedly connected to the first nut (21), the pressure plate (31) presses the cylinder liner (3) tightly in the mounting position, thereby achieving the joining of the cylinder liner (3) and the pump body (1) by the first nut (21) in conjunction with the screw (2); the first nut (21) is located between the cylinder liner (3) and the tool; characterized in that: The device includes a cylinder (4) that can be positioned and connected to a bolt. The bottom of the cylinder (4) is closed. A piston plate (5) is slidably connected inside the cylinder (4). A hydraulic oil chamber (44) is formed between the piston plate (5) and the bottom of the cylinder (4). A hydraulic oil connector (7) is provided on the cylinder (4). The hydraulic oil connector (7) is connected to the hydraulic oil chamber (44). When hydraulic oil is gradually filled into the hydraulic oil chamber (44), the cylinder (4) can stretch and move with the bolt, so that the bolt undergoes elastic deformation along its own axial direction. A connecting flange (41) is provided at one end of the cylinder (4). A connecting hole for the bolt to pass through is provided on the connecting flange (41). The bolt thread (2) can pass through the connecting hole and be positioned and locked by a second nut (22). The connecting flange (41) replaces the connection between the end of the cylinder (4) and the thread (2).

2. The disassembly and assembly tool according to claim 1, characterized in that: A sealing ring (51) is provided between the piston plate (5) and the inner wall of the cylinder (4).

3. The disassembly and assembly tool according to claim 1, characterized in that: A sealing plate (43) is provided at the other end of the cylinder (4), and the sealing plate (43) seals the bottom of the cylinder (4).

4. The disassembly and assembly tool according to claim 3, characterized in that: A load-bearing connector (42) is provided between the connecting flange (41) and the sealing plate (43).

5. The disassembly and assembly tool according to claim 1, characterized in that: The cylinder (4) is provided with a limiting member (45), and the piston plate (5) is assembled between the limiting member (45) and the bottom of the cylinder (4).

6. The disassembly and assembly tool according to claim 1, characterized in that: A handle (6) is provided on the outer surface of the cylinder (4).

7. The disassembly and assembly tool according to any one of claims 1-6, characterized in that: It also includes a ratchet wrench (8), which includes a ratchet head (82) with a constraint hole (83) that matches the shape of the nut in the bolt. The ratchet head (82) is rotatably connected to a lifting rod (81), and the position of the rotatable connection between the ratchet head (82) and the lifting rod (81) does not coincide with the axis of the constraint hole (83).

8. A method for disassembling and assembling a cylinder liner of an oil and gas drilling pump, characterized in that: Includes the following steps: S1: Install cylinder liner (3); see steps S11-S15 for details; S11: Use the first nut (21) in conjunction with the screw (2) to engage the cylinder liner (3) with the pump body (1) to complete the initial engagement; S12: Install the disassembly and assembly tool for the oil and gas drilling pump cylinder liner as described in any one of claims 1-7; after passing the screw (2) through the connecting hole, connect the second nut (22), the second nut (22) restricts the position of the disassembly and assembly tool relative to the screw (2); connect the hydraulic oil connector (7) to the hydraulic oil supply device; S13: the hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber (44) through the hydraulic oil connector (7), the hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber (44), the hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber (44) through the hydraulic oil connector (7), the hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber (44) ... Hydraulic oil exists between the piston plate (5) and the bottom of the cylinder (4). The hydraulic oil pushes the piston plate (5) against the cylinder liner (3) or pump body (1). The cylinder liner (3) or pump body (1) restricts the movement of the piston plate (5). The hydraulic oil reacts to the bottom of the cylinder (4). The cylinder (4) moves along the axis of the screw (2) in a stretching motion. The screw (2) undergoes elastic deformation and has elastic force. The first nut (21) moves away from the engagement position along with the screw (2). S14: Tighten the first nut (21). The first nut (21) returns to the engagement position, completing the re-engagement. S15: Discharge the hydraulic oil. The screw (21) moves away from the engagement position. The elastic deformation of the screw (2) cannot be recovered due to the presence of the first nut (21). The elastic energy generated by the elastic deformation of the screw (2) is transmitted between the cylinder liner (3) and the pump body (1) through the first nut (21), forming a preload force between the cylinder liner (3) and the pump body (1); the installation of the cylinder liner (3) is completed; S2: disassemble the cylinder liner (3); see steps S21-S25 for details; S21: use steps S11-12 to install the disassembly and assembly tools for the oil and gas drilling pump cylinder liner as described in any one of claims 1-7; S22: the hydraulic oil supply device supplies hydraulic oil to the hydraulic oil chamber (44) through the hydraulic oil connector (7), and the hydraulic oil supply device provides hydraulic oil to the hydraulic oil chamber (44). Oil exists between the piston plate (5) and the bottom of the cylinder (4). The hydraulic oil pushes the piston plate (5) against the cylinder liner (3) or the pump body (1). The cylinder liner (3) or the pump body (1) restricts the movement of the piston plate (5). The hydraulic oil reacts to the bottom of the cylinder (4). The pressure of the hydraulic oil overcomes the preload force between the cylinder liner (3) and the pump body (1) when the first nut (21) is engaged. S23: Tighten the first nut (21) and the first nut (21) is disengaged from the engaged position. There is no preload force between the cylinder liner (3) and the pump body (1) after the hydraulic oil is removed. S24: Continue to tighten the first nut (21) to complete the disassembly of the cylinder liner (3).

9. The disassembly and assembly method according to claim 8, characterized in that: If a preload is required between the cylinder liner (3) and the pump body (1), the first nut (21) only needs to be used to tighten the cylinder liner (3) and the pump body (1) to zero during the initial engagement and re-engagement in steps S11 and S14 when installing the cylinder liner (3).

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