Sudden change pressure intensity testing device for roller bit magnetic flow sealing

Abstract

The invention relates to the technical field of testing equipment, in particular to a sudden change pressure intensity testing device for roller bit magnetic flow sealing, which can provide sudden change pressure for magnetic flow sealing while performing steady-state pressure testing, and is convenient for testing and checking dynamic compensation and stability of the magnetic flow sealing at the sudden change pressure intensity. Comprising a workbench; a steady-state pressure applying module, a dynamic pressure applying module, a roller bit module, a data acquisition module and a control module are respectively arranged on the workbench; the steady-state pressure applying module is communicated with the dynamic pressure applying module through a pipeline, the steady-state pressure applying module is used for applying set pressure to the roller bit module, and the dynamic pressure applying module is used for providing sudden change pressure to the roller bit module; the data acquisition module is used for acquiring pressure intensity data borne by the roller bit module and magnetic current sealing deformation data under the corresponding pressure intensity; and the control module outputs dynamic response data of the roller bit module according to the data acquired by the data acquisition module.

Description

Technical Field

[0001] This invention relates to the field of testing equipment technology, and specifically to a sudden pressure testing device for magnetohydrodynamic seals of roller cone drill bits. Background Technology

[0002] Roller cone bits are the most widely used type of drilling bit. During operation, the cutting teeth of a roller cone bit alternately contact the bottom of the well, resulting in low rock-breaking torque, a small contact area between the cutting teeth and the bottom of the well, high specific pressure, and easy penetration into the formation. The large total length of the working cutting edge reduces wear, allowing roller cone bits to adapt to various formations from soft to hard. In practical use, roller cone bits need to be sealed to prevent dust and gravel from entering bearings and other parts of the drill bit, causing different levels of wear.

[0003] The sealing performance of roller cone drill bits mainly relies on the synergistic effect of the following core technologies and designs. The mainstream sealing method is metal end face sealing, which is usually composed of a pair of precision-machined annular metal end faces (one moving ring is fixed on the roller cone and rotates with the roller cone, and one stationary ring is fixed on the roller cone bearing journal and remains stationary) tightly fitted together; sealing grease and elastic sealing rings are also used for sealing.

[0004] Among them, since the drill bit bearing seals of downhole tools such as measurement while drilling / logging while drilling systems need to cope with many extreme conditions, such as high temperature, high pressure, high speed and abrasive environment, new sealing technologies have been proposed. For example, the invention application with application number CN202210545596.8 discloses a spiral magnetofluid composite sealing structure for roller cone drill bits, which achieves sealing through spiral magnetofluid. Its sealing structure can meet the requirements of high reliability, long service life, high temperature resistance and high speed resistance.

[0005] In reality, the pressure-bearing capacity of helical magnetic fluids is limited. Existing magnetic fluid sealing structures improve reliability through active sand removal. However, before actual production, pressure tests on helical magnetic fluids are required. Current pressure tests are usually based on steady-state hydraulic loading. However, there are many sudden pressure changes in the downhole environment, and the dynamic compensation effect and stability of magnetic fluids under sudden pressure changes lack experimental verification. Furthermore, the methods and means for testing stability under sudden pressure changes are not perfect. Summary of the Invention

[0006] I. Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention proposes a sudden pressure testing device for magnetohydrodynamic seals in roller cone drill bits. This device can provide sudden pressure to the magnetohydrodynamic seal while performing steady-state pressure testing, facilitating the testing and verification of the dynamic compensation and stability of the magnetohydrodynamic seal under sudden pressure changes.

[0008] II. Specific Technical Solutions

[0009] A device for testing sudden pressure on the magnetohydrodynamic seal of a roller cone drill bit includes a worktable; the worktable is respectively equipped with a steady-state pressure application module, a dynamic pressure application module, a roller cone drill bit module, a data acquisition module, and a control module; the steady-state pressure application module and the dynamic pressure application module are connected by a pipeline, the steady-state pressure application module is used to apply a set pressure to the roller cone drill bit module, and the dynamic pressure application module is used to provide sudden pressure on the roller cone drill bit module; the data acquisition module is used to collect pressure data borne by the roller cone drill bit module and magnetohydrodynamic seal deformation data under the corresponding pressure; the control module outputs dynamic response data of the roller cone drill bit module based on the data collected by the data acquisition module.

[0010] Implementation principle and working principle:

[0011] In this scheme, the control program is first input into the control system. The control system first opens the roller cone drill bit module and then the steady-state pressure module. After the steady-state pressure module maintains constant pressure, the control system opens the dynamic pressure module. Finally, it collects deformation data and pressure change data of the magnetohydrodynamic seal and feeds the collected data back to the control module. The control module then controls zeroing to perform a second data collection, repeating this process n times before outputting the data. This device can simulate the sudden changes in the magnetohydrodynamic seal downhole, collect the peak pressure that the magnetohydrodynamic seal can withstand, and conduct repeated experiments to calibrate and verify the experimental values, thereby achieving accurate detection of the seal performance under sudden pressure changes. Preferably, the steady-state pressure module includes a sealing sleeve; the roller cone drill bit module includes a magnetohydrodynamic seal structure, which is disposed inside the sealing sleeve; the sealing sleeve is also connected to a booster pump via a pipeline. The beneficial effect of this preferred scheme is that, by controlling the parameters of the booster pump through the control module, the pressure inside the sealing sleeve can be controlled, thereby providing a steady-state pressure for the magnetohydrodynamic seal. Preferably, the sealing sleeve is further provided with several observation ports; the observation ports are arranged opposite to the data acquisition module, which includes a peak pressure gauge and a high-speed camera; the high-speed camera corresponds to the magnetohydrodynamic sealing structure through the observation ports; the beneficial effect of this preferred embodiment is that, through the setting of the peak pressure gauge, the pressure change value and peak value inside the sealing sleeve can be directly collected, and at the same time, the deformation of the magnetohydrodynamic seal can be continuously acquired by the high-speed camera, which can be correlated with the pressure value collected by the peak pressure gauge, so as to better evaluate and test the changes of the magnetohydrodynamic seal under sudden pressure changes.

[0012] Preferably, the workbench also includes a mounting plate above the table surface, on which a drive motor is mounted on the side opposite to the table surface; the output end of the drive motor is connected to a rotating shaft; the other end of the rotating shaft passes through the sealing sleeve and is rotatably connected to the table surface via a bearing; the magnetohydrodynamic sealing structure is rotatably connected to the bottom of the rotating shaft, and a rotary seal is provided at the point where the rotating shaft passes through the sealing sleeve; the advantage of this preferred embodiment is that by driving the roller cone drill bit vertically with the drive motor, it is beneficial to better simulate the scenario of downhole drill bit rotation, making the test results more accurate and realistic.

[0013] Preferably, the dynamic pressure module includes a pressure cylinder; the pressure cylinder is connected to the steady-state pressure module via a pipe; a piston is provided at the top of the pressure cylinder; a traction unit is provided above the pressure cylinder; a pressure block is provided at the traction end of the traction unit, and the traction unit releases the pressure block from a set height to impact the piston; the beneficial effect of this preferred embodiment is that this solution provides a sudden pressure change by releasing the pressure block from a set height, that is, the gravitational potential energy is converted into the impact of the piston, and the conversion can be directly performed by a formula, which is conducive to controlling the amount of pressure. The peak pressure gauge used can accurately collect the pressure change, avoiding the influence caused by different energy losses during the impact process.

[0014] Preferably, the bottom of the pressure cylinder is provided with a support platform; the bottom of the pressure cylinder is provided with a connection hole for pipe connection; the support platform is provided with a pipe hole for pipe installation; the combination of the support platform and the connection hole at the bottom of the pressure cylinder facilitates pipe installation and provides more space for piston movement, ensuring smooth piston movement. Preferably, the upper end face of the piston is provided with a pressure plate; the upper end of the pressure cylinder is provided with a limiting part; the limiting part is used to prevent the piston from disengaging from the pressure cylinder; the beneficial effect of this preferred embodiment is that the pressure plate can prevent the piston from being directly impacted and causing irreversible deformation, and the limiting part can prevent the piston from disengaging from the pressure cylinder during reset.

[0015] Preferably, the traction unit includes a traction motor; the output end of the traction motor is connected to a winch; the traction rope on the winch is connected to an electromagnetic chuck; the electromagnetic chuck can be magnetically attracted and connected to the pressure block; the beneficial effect of this preferred embodiment is that, through the combination of the traction motor, winch and electromagnetic chuck, on the one hand, it is convenient to measure the height of the pressure block, and on the other hand, it is convenient to automatically reset the pressure block, resulting in a higher degree of automation and higher reproduction accuracy.

[0016] Preferably, a guide component is also provided inside the pressurizing cylinder; the guide component passes through the pressure plate, piston, pressurizing block and electromagnetic suction plate; the beneficial effect of this preferred embodiment is that, by setting the guide component, the force on the pressurizing block can always be in a uniform position, the reproducibility of the test is higher, and it can better meet the requirements of repeated measurement and verification.

[0017] The beneficial effects of this invention are as follows:

[0018] Through the collaborative design of steady-state pressure application module and dynamic pressure application module, the composite loading of steady-state high pressure and transient pressure impact in downhole has been realized for the first time. It accurately reproduces extreme working conditions such as sudden changes in rock formation and blowouts when the drill bit encounters them, and solves the industry pain point that the behavior of magnetohydrodynamic seals under dynamic pressure is difficult to verify.

[0019] Improved testing accuracy and efficiency: High-precision synchronous acquisition, with millisecond-level synchronization between the peak pressure gauge (501) and the high-speed camera, achieves accurate correlation of pressure-deformation data with an error of <1%; Repeatable impact control, with guide components ensuring consistent impact trajectory for each test, and electromagnetic chuck achieving automatic reset, shortens the single test cycle to 5 minutes with a repeatability error of ≤3%.

[0020] Based on dynamic response data, the following can be quantitatively analyzed: the dynamic compensation rate of the magnetohydrodynamic fluid under sudden pressure changes (such as deformation recovery time); the critical failure pressure threshold (the sudden peak value when the sealing gap expands to failure); and the fatigue resistance characteristics (the sealing performance decay curve after repeated impacts), providing direct experimental basis for the optimization of sealing structures.

[0021] In practical applications, the steady-state pressure module of this solution can inject hydraulic oil or other media into the sealing sleeve and apply pressure to the media. The magnetic fluid seal is driven by a vertically set drive motor and rotating shaft, which can better simulate the complex situation of the roller cone drill bit module downhole and is more realistic.

[0022] The support platform allows the pipe hole of the pressure cylinder to be located at the bottom, enabling a wider range of piston movement during operation and facilitating smooth piston reset. The pressure cylinder and the sealing sleeve are connected by a pipe, ensuring that the pressure at both ends is basically the same. When the steady-state pressure module is running, it can reset the piston, facilitating subsequent pressure application by the dynamic pressure module. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the control logic in an embodiment of the present invention.

[0024] Figure 2 This is an isometric schematic diagram of the sudden pressure testing device for the magnetohydrodynamic seal of a roller cone drill bit according to an embodiment of the present invention.

[0025] Figure 3This is a cross-sectional schematic diagram of the sudden pressure testing device for the magnetohydrodynamic seal of a roller cone drill bit according to an embodiment of the present invention.

[0026] Explanation of reference numerals in the attached figures:

[0027] Workbench 1, Mounting plate 101;

[0028] Steady-state pressure application module 2, sealing sleeve 201, booster pump 202, observation port 203;

[0029] Dynamic pressure module 3, pressure cylinder 301, piston 302, traction unit 303, pressure block 304, support platform 305, connecting hole 306, pipe hole 307, pressure plate 308, limiting part 309, traction motor 310, winch 311, electromagnetic suction plate 312, guide component 313;

[0030] 4. Roller cone drill bit module, 401. Magnetorheological seal structure, 402. Drive motor, 403. Shaft, 404. Bearing.

[0031] Data acquisition module 5, peak voltage gauge 501, high-speed camera 502;

[0032] Control module 6. Detailed Implementation

[0033] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0034] like Figure 1-3 As shown:

[0035] A sudden pressure testing device for magnetohydrodynamic seal of roller cone drill bit includes a workbench 1, which serves as the mounting base or frame for the entire device; specifically, a steady-state pressure application module 2, a dynamic pressure application module 3, a roller cone drill bit module 4, a data acquisition module 5, and a control module 6 are respectively arranged on the workbench 1.

[0036] In specific implementation, such as Figure 2 and 3The steady-state pressure application module 2 and the roller cone drill bit module 4 are specifically arranged on the left side of the workbench 1. The steady-state pressure application module 2 includes a sealing sleeve 201; the roller cone drill bit module 4 includes a magnetic flux sealing structure 401, which is disposed inside the sealing sleeve 201. An installation plate 101 is installed on the top of the workbench, and a booster pump 202 is installed on the right side of the bottom of the installation plate 101. The output end of the booster pump 202 is connected to the sealing sleeve 201 through a pipe to adjust the pressure inside the sealing sleeve 201. By setting the booster pump 202, the pressure inside the sealing sleeve 201 can be controlled, thereby providing steady-state pressure to the magnetic flux seal 401.

[0037] In specific implementation, the sealing sleeve 201 is made of acrylic, and the entire sealing sleeve 201 can serve as an observation port 203. The observation port 201 facilitates data acquisition by the data acquisition module 5. Specifically, the data acquisition module 5 includes a peak pressure gauge 501 and a high-speed camera 502. The high-speed camera 502 corresponds to the magnetohydrodynamic seal structure 401 through the observation port 203, so as to better observe the changes in the magnetohydrodynamic seal. Through the setting of the peak pressure gauge 501, the pressure change value and peak value inside the sealing sleeve 201 can be directly acquired. At the same time, the high-speed camera 502 can continuously acquire the deformation of the magnetohydrodynamic seal 401, which can be correlated with the pressure value acquired by the peak pressure gauge, so as to better evaluate and test the changes in the magnetohydrodynamic seal under sudden pressure changes.

[0038] In practice, a drive motor 402 is installed on the left side of the bottom of the mounting plate 101. The output end of the drive motor 402 is connected to a rotating shaft 403 via a coupling. The other end of the rotating shaft 403 passes through the sealing sleeve 201 and is rotatably connected to the table surface of the workbench 1 via a bearing 404. In practice, the rotating shaft 403 and the sealing sleeve 201 are sealed by rotation. The magnetohydrodynamic sealing structure 402 is rotatably connected to the bottom of the rotating shaft 403. The drive motor 402 drives the roller cone drill bit vertically, which helps to better simulate the scenario of the downhole drill bit rotation, making the test results more accurate and realistic.

[0039] In specific implementation, the dynamic pressure module 3 includes a pressure cylinder 301. The pressure cylinder 301 is connected to the sealing sleeve 201 of the steady-state pressure module 2 via a pipe. The advantage of this arrangement is that the pressure in the sealing sleeve 201 and the pressure cylinder is consistent, and the pressure from the steady-state pressure module 2 can also drive the pressure cylinder 301 to reset. A piston 302 is provided at the top of the pressure cylinder 301. A traction unit 303 is provided above the pressure cylinder 302. A pressure block 304 is provided at the traction end of the traction unit 303. The traction unit 303 releases the pressure block 304 from a set height to impact the piston 302, and can then re-retrieve the piston after release. The sudden pressure is provided by releasing the pressure block 304 from a set height, that is, the impact of the piston is converted from gravitational potential energy. This conversion can be directly converted by a formula, which is beneficial for controlling the amount of pressure. The peak pressure gauge 501 used can accurately collect the pressure change, avoiding the influence caused by different energy losses during the impact process.

[0040] In implementation, the traction unit 303 includes a traction motor 310; the output end of the traction motor 310 is connected to a winch 311; the traction rope on the winch 311 is connected to an electromagnetic suction plate 312; the electromagnetic suction plate 312 can be connected to the pressure block 304 through magnetic attraction; through the combination of the traction motor 310, the winch 311 and the electromagnetic suction plate 312, it is convenient to measure the height of the pressure block 304 on the one hand, and to automatically reset the pressure block 304 on the other hand, with a higher degree of automation and higher reproducibility; in implementation, a guide component 313 is also provided in the pressure cylinder 301; the guide component 301 passes through the pressure plate 308, the piston 302, the pressure block 304 and the electromagnetic suction plate 312, and the guide component 301 is specifically a guide post to ensure that the landing point of the pressure block 304 is consistent; through the setting of the guide component 313, the force on the pressure block 304 can always be located in the same position, the reproducibility of the test is higher, and it can better meet the requirements of repeated measurement and verification.

[0041] In specific implementation, a support platform 305 is provided at the bottom of the pressure cylinder 301, which can play a certain buffering role; a connection hole 306 is provided at the bottom of the pressure cylinder 301, which is used for pipe connection; in specific implementation, a pipe hole 307 is provided in the support platform 305, which is used for pipe installation, wherein the pipe is also connected to a tee connector, which is connected to the booster pump 202, the pressure cylinder 301 and the sealing sleeve 201 respectively; by setting the support platform 305 and setting the connection hole 306 at the bottom of the pressure cylinder 301, this combination is conducive to pipe installation, and at the same time, it can provide more sufficient space for the movement of the piston 302, ensuring that the piston 302 can move smoothly.

[0042] In a specific implementation, a pressure-bearing plate 308 is bonded to the upper end face of the piston 302, and the area of ​​the pressure-bearing plate is smaller than that of the piston 302 and can be limited by the limiting part 309; a limiting part 309 is provided at the upper end of the pressurizing cylinder 301, and the limiting part 309 is formed by the top of the pressurizing cylinder 301 extending radially; the limiting part 309 can effectively prevent the piston 302 from disengaging from the pressurizing cylinder 301 when the booster pump pressurizes and drives the piston.

[0043] This solution also provides a control module 6 with a touch screen. This control module 6 is specifically a control panel, which is electrically connected to the data acquisition module 5. Specifically, it is communicatively connected to the peak pressure gauge 501 and the high-speed camera 502. It can synchronously display pressure data and deformation data of the magnetohydrodynamic seal 401, and can output the data under sudden pressure changes in a graphical comparison manner. The control module 6 can control the traction motor 310, the booster pump 202, and the drive motor 402 to achieve test result reproduction and intelligent control without manual intervention, resulting in a higher degree of automation. The combination of static pressure and dynamic pressure values ​​can accurately match the real data of the roller cone drill bit sealing component when subjected to sudden pressure changes in the rock environment.

[0044] In practice:

[0045] 1. First, assemble and connect the device:

[0046] The rotating shaft 403 of the roller cone drill bit module 4 is vertically mounted on the bearing 404 of the workbench 1, and the drive motor 402 is connected to the top of the rotating shaft through a coupling; the sealing sleeve 201 covers the magnetohydrodynamic sealing structure 401, and the bottom is sealed and fixed to the workbench, and the side wall is connected to the booster pump 202 and the connection hole 306 at the bottom of the pressurizing cylinder 301 through high pressure pipes respectively; the high-speed camera 502 is aligned with the observation port 204, and the sensor of the peak pressure gauge 501 is embedded in the inner wall of the sealing sleeve; then the guide component 313 of the traction unit 303 is vertically passed through the electromagnetic suction plate 312, the pressurizing block 304 and the piston 302 to ensure that the impact trajectory is coaxial.

[0047] 2. Testing Process

[0048] Step 1: Steady-state pressure simulation

[0049] First, the control program is input into the control module 6. Then, the control module 6 controls the drive motor 402 to rotate, which in turn drives the shaft 403 to rotate at the rated speed, such as 200 rpm, to simulate the working state of the drill bit. When the rated speed is reached, the control module controls the static pressure module 2 to increase the pressure. Specifically, it controls the booster pump 202 to start and increase the pressure into the sealing sleeve 201. The pressure rises to the set value, such as 20 MPa, to simulate the steady-state working condition downhole.

[0050] Step 2: Sudden Pressure Loading

[0051] When the pressure in the static pressure application module 2 is stable, the control module activates the dynamic pressure application module 3 to apply a sudden pressure. Specifically, the control module issues a command to drive the traction motor 310, which in turn lifts the electromagnetic suction plate 312 to a preset height, adsorbs the pressure block 304, and then releases it by cutting off the power. The pressure block 304 falls freely along the guide component 313, impacts the piston 302, and converts the kinetic energy into a sudden pressure of the liquid in the cylinder, such as a transient peak of 50MPa. The sudden pressure is transmitted to the sealing sleeve 201 through the pipeline and acts on the rotating magnetohydrodynamic sealing structure 401.

[0052] Step 3: Data Collection and Analysis

[0053] The peak pressure gauge 501 records the pressure-time curve in real time, captures sudden peak values ​​and decay rates, and transmits the collected data to the control module 6. The high-speed camera 502 captures the deformation process of the magnetohydrodynamic seal at a frame rate of 1000fps, quantifies the changes in the sealing gap through image analysis software, and then transmits the data to the control module 6 to synchronize the pressure and deformation data, generate a dynamic response curve, and calculate the critical value for seal failure.

[0054] Step 4: The control module 6 automatically adjusts to 0, and after repeating the experiment N times, the experimental data is output.

[0055] 3. Key parameter control

[0056] Sudden Pressure Regulation: By changing the mass (m) or drop height (H) of the pressure block 304, the impact pressure is precisely controlled according to the formula P=k·m·g·H / A, where k is the energy conversion coefficient and A is the piston area.

[0057] Rotary sealing protection: The combination structure of double O-rings and mechanical seal between the rotating shaft 403 and the sealing sleeve 201 is adopted to prevent high pressure leakage.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims.

Claims

1. A device for testing sudden pressure changes in magnetohydrodynamic seals of roller cone drill bits, characterized in that: The system includes a workbench (1); the workbench (1) is equipped with a steady-state pressure module (2), a dynamic pressure module (3), a roller cone drill bit module (4), a data acquisition module (5), and a control module (6); the steady-state pressure module (2) and the dynamic pressure module (3) are connected by a pipeline; the steady-state pressure module (2) is used to apply a set pressure to the roller cone drill bit module (4), and the dynamic pressure module (3) is used to provide a sudden pressure to the roller cone drill bit module (4); the data acquisition module (5) is used to collect the pressure data and the magnetic flux sealing deformation data under the corresponding pressure of the roller cone drill bit module (4); the control module (6) controls the operation of the steady-state pressure module (2), the dynamic pressure module (3), and the roller cone drill bit module (4) according to the data collected by the data acquisition module (5), and outputs the response data of the corresponding modules.

2. The sudden pressure testing device for magnetohydrodynamic sealing of roller cone drill bits according to claim 1, characterized in that: The steady-state pressure module (2) includes a sealing sleeve (201); the roller cone drill bit module (4) includes a magnetic fluid sealing structure (401), which is disposed inside the sealing sleeve (201); the sealing sleeve (201) is also connected to a booster pump (202) via a pipeline.

3. The sudden pressure testing device for magnetofluidic seal of roller cone drill bits according to claim 2, characterized in that: Several observation ports (203) are also provided on the sealing sleeve (201); the observation ports (203) are arranged opposite to the data acquisition module (5), the data acquisition module (5) includes a peak pressure gauge (501) and a high-speed camera (502); the high-speed camera (502) is connected to the magnetohydrodynamic sealing structure (401) through the observation ports (203).

4. The sudden pressure testing device for magnetofluidic seal of roller cone drill bits according to claim 2, characterized in that: The workbench (1) also includes a mounting plate (101) above the table surface. The mounting plate (101) has a drive motor (402) on the side opposite to the table surface. The output end of the drive motor (402) is connected to a rotating shaft (403). The other end of the rotating shaft (403) passes through the sealing sleeve (201) and is rotatably connected to the table surface of the workbench (1) through a bearing (404). The magnetohydrodynamic sealing structure (402) is rotatably connected to the bottom of the rotating shaft (403) and performs a rotational seal at the penetration point between the rotating shaft (403) and the sealing sleeve (201).

5. The sudden pressure testing device for magnetofluidic seals of roller cone drill bits according to claim 1, characterized in that: The dynamic pressure module (3) includes a pressure cylinder (301); the pressure cylinder (301) is connected to the steady-state pressure module (2) through a pipe; a piston (302) is provided on the top of the pressure cylinder (301); a traction unit (303) is provided above the pressure cylinder (301); a pressure block (304) is provided at the traction end of the traction unit (303), and the traction unit (303) releases the pressure block (304) from a set height to impact the piston (302).

6. The sudden pressure testing device for magnetohydrodynamic sealing of roller cone drill bits according to claim 5, characterized in that: The pressure cylinder (301) has a support platform (305) at its bottom; the pressure cylinder (301) has a connection hole (306) at its bottom, which is used for pipe connection; the support platform (305) has a pipe hole (307) inside, which is used for pipe installation.

7. The sudden pressure testing device for magnetofluidic seals of roller cone drill bits according to claim 5, characterized in that: The piston (302) has a pressure plate (308) on its upper end face; the pressure cylinder (301) has a limiting part (309) on its upper end; the limiting part (309) is used to prevent the piston (302) from disengaging from the pressure cylinder (301).

8. The sudden pressure testing device for magnetofluidic seal of roller cone drill bits according to claim 5, characterized in that: The traction unit (303) includes a traction motor (310); the output end of the traction motor (310) is connected to a winch (311); the traction rope on the winch (311) is connected to an electromagnetic suction plate (312); the electromagnetic suction plate (312) can be connected to the pressure block (304) by magnetic attraction.

9. The sudden pressure testing device for magnetofluidic seals of roller cone drill bits according to claim 5, characterized in that: The pressure cylinder (301) is also provided with a guide component (313); the guide component (313) passes through the pressure plate (308), piston (302), pressure block (304) and electromagnetic suction plate (312).

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