Testing machine for testing sealing performance of sealing pair of control valve

Abstract

The utility model discloses a testing machine for testing the sealing performance of a sealing pair of a control valve, which comprises a closed box body, a rotary driving mechanism, a rotary lifting assembly, a lower sample replacement block, a telescopic cylinder, an upper sample replacement block, a liquid pressure supply system and a gas pressure supply system, and the rotary driving mechanism is arranged in the closed box body; the rotary lifting assembly is located in the closed box and is in transmission connection with the rotary driving mechanism. The lower sample replacement block is mounted at the top of the rotary lifting assembly; the telescopic cylinder is mounted in the closed box body and is connected with the rotary lifting assembly; the upper sample replacement block is mounted at the top of the closed box body and corresponds to the lower sample replacement block; the liquid pressure supply system is connected and communicated with the sealed cavity of the upper sample replacement block; the gas pressure supply system is aligned with a sealing interface formed between the upper sample replacement block and the lower sample replacement block; and the leakage detection system is electrically connected with the data acquisition and control system. The device can improve the applicability, quantify the sealing leakage rate of the valve, and comprehensively evaluate the sealing performance of the control valve.

Description

Technical Field

[0001] The utility model relates to the technical field of sealing performance testing equipment, and more specifically, to a sealing performance testing machine for a control valve sealing pair. Background Art

[0002] High-end control valves are used in a wide variety of fields with special conditions, covering ultra-high pressure and ultra-high temperature pipe networks, nuclear island and conventional island safety systems, aero-engine power systems, space station environmental control and life support systems, submarine diving and trimming systems, etc. Therefore, extremely stringent requirements are imposed on the sealing reliability of control valves. The sealing pair of high-end control valves is different from traditional mechanical seals. Its service environment is mostly extreme and harsh conditions such as high temperature, high pressure difference, strong corrosion, and strong wear, which will cause serious problems such as cavitation, erosion, corrosion, thermal deformation, blockage, indentation, and scratching. Especially at the moment when the control valve opens and closes, a high-speed jet will be generated at the opening and closing gap, severely damaging the surface of the sealing pair. In addition, the control valve sealing pair is different from traditional static and dynamic seals and needs to maintain a high-level sealing performance during the static closing and dynamic opening processes of the control valve.

[0003] Currently, the mainstream sealing theory is based on the sealing specific pressure model. This model can consider the influence of the material properties, roughness, and size of the sealing surface, and requires that the sealing specific pressure generated by the sealing force should be greater than the necessary sealing specific pressure. In the sealing design of control valves under conventional working conditions, the sealing specific pressure model can provide good theoretical guidance. However, it is found in the research and development of high-end control valve products that the sealing specific pressure theory can no longer meet the design requirements under extreme working conditions. Some products can still pass the sealing performance test even though the indentation on the sealing surface does not reach the designed width (the coincidence degree < 65%); at the same time, some products with sealing surfaces meeting the model requirements still cannot achieve sealing. Therefore, the existing sealing specific pressure model has great limitations. Its model parameters simplify the influence of the elastic modulus, sealing surface width, and roughness changes, lack the quantitative characterization of the microscopic sealing mechanism, and cannot essentially explain the basic principle of sealing. In particular, it is impossible to evaluate the influence of fluids with ultra-conventional physical properties, complex multiphase fluids, extreme temperatures, ultra-high pressures, and extreme loads on the sealing performance of control valves, and it is difficult to meet the sealing design requirements of control valves under extreme working conditions.

[0004] In order to change the status quo, some control valve sealing performance testing machines have also appeared in the prior art to detect the sealing performance of control valves in the closed state, but there are still some technical problems:

[0005] For example, in a Chinese patent with the publication number CN219391251U and the patent name "A Detection Device for the Leakage Volume of a Valve in Low-Pressure Gas Sealing Test", a detection device for the leakage volume of a valve in low-pressure gas sealing test is disclosed, which includes a high-precision gas flowmeter, a bubble counter, a bubble dish, a valve under test, a right pressure gauge, a flow control assembly, and a right inlet valve. The device can accurately count the bubbles in the bubble dish through the bubble counter, or control the leakage gas in the pipeline of the flow control assembly to flow to the high-precision gas flowmeter, so as to obtain the gas flow rate. Then, the obtained measurement results are manually or transmitted and imported into an intelligent device for calculation to determine whether the valve under test meets the standard of low-pressure gas sealing. Although the problems of low accuracy and poor accuracy in measuring the number of leaked bubbles and leakage flow rate in the existing device can be solved by the bubble counting method or the flow measurement method, this detection device is mainly for the detection of low-pressure gas sealing performance and may not be applicable or require corresponding adjustments for high-pressure environments or other types of seal tests; in addition, the device is designed to detect the gas leakage volume of the valve under low-pressure conditions and does not clearly mention the detection ability for liquid leakage.

[0006] For another example, in a Chinese patent with the publication number CN117168706A and the patent name "A Valve Sealing Performance Test Equipment", a valve sealing performance test equipment is disclosed, which includes a base; a rectangular cylinder with an open upper end is installed on the upper end surface of the base. An injection pipe is arranged on the left side of the rectangular cylinder, a cover plate is arranged on the upper end surface of the rectangular cylinder, a driving mechanism for driving the cover plate to fit with the rectangular cylinder is arranged on the base, a limiting mechanism for pre-positioning the valve is arranged at the lower end of the cover plate, a rotating mechanism for driving the valve to open and close is arranged on the cover plate, and two pressure applying mechanisms for adjusting the internal pressure of the valve are symmetrically arranged on the left and right of the cover plate. Although it can be used to detect whether the valve is completely sealed, so as to solve the technical problems in the related art that it is not easy to observe the minute leakage of the valve through a foaming agent or a differential pressure gauge and that the valve airtightness test is only carried out under the same external pressure and cannot comprehensively evaluate the performance of the valve, etc., the design of this equipment focuses on identifying the minute leakage of the valve through underwater detection. However, for special materials or application scenarios that cannot be in contact with water, this method may be unreasonable. In addition, the equipment is designed for specific types of valves and may require customized adjustments for different sizes or types of valves, which will increase the overall test cost; finally, the main objective of the equipment is to detect the sealing performance of the valve, especially to judge whether there is minute leakage by observing whether there are bubbles generated. This is a qualitative rather than quantitative detection method and does not provide specific means to quantify the leakage volume, such as leakage rate or leakage volume.

[0007] Therefore, it is an urgent problem for those skilled in the art to provide a test machine for testing the sealing performance of a control valve sealing pair. Utility Model Content

[0008] In view of this, the present utility model provides a testing machine for testing the sealing performance of a control valve sealing pair, which can improve applicability, quantify the valve sealing leakage amount, and comprehensively evaluate the sealing performance of the control valve.

[0009] In order to achieve the above object, the present utility model adopts the following technical solutions:

[0010] A testing machine for testing the sealing performance of a control valve sealing pair includes a sealed box body, a rotary drive mechanism, a rotary lifting assembly, a lower specimen replacement block, a telescopic cylinder, an upper specimen replacement block, a liquid pressure supply system, a gas pressure supply system, a leakage detection system, and a data acquisition and control system. The rotary drive mechanism is installed inside the sealed box body; the rotary lifting assembly is located inside the sealed box body and is in transmission connection with the rotary drive mechanism; the lower specimen replacement block is installed at the top of the rotary lifting assembly; the telescopic cylinder is installed inside the sealed box body and its telescopic rod is fixedly connected with the rotary lifting assembly; the upper specimen replacement block is installed at the top of the sealed box body and corresponds to the position of the lower specimen replacement block; the liquid pressure supply system is connected and communicated with the sealing cavity of the upper specimen replacement block; the gas pressure supply system is aligned with the sealing interface formed between the upper specimen replacement block and the lower specimen replacement block; the leakage detection system is electrically connected with the data acquisition and control system.

[0011] Further, the lower specimen replacement block is conical, the bottom plane of the lower specimen replacement block is inclined downward from the conical main body towards the cone head direction and a leakage hole is provided at the position of the cone head; the leakage detection system includes a beaker, an electronic balance, and a helium mass spectrometer. The beaker is placed inside the sealed box body and is located directly below the leakage hole; the helium mass spectrometer is connected and communicated with the sealed box body; the electronic balance and the helium mass spectrometer are respectively electrically connected with the data acquisition and control system.

[0012] Further, the rotary lifting assembly includes a base, a shaft core, a bearing sleeve, a bearing, a disk-shaped gear, and a bearing end cover. The telescopic rod of the telescopic cylinder is fixedly connected with the base; the shaft core is located at the top of the base and is rotationally connected thereto; the bearing sleeve is sleeved on the shaft core; the inner side surface of the bearing sleeve is provided with a lower positioning shoulder; the bearing is installed on the shaft core and is located inside the bearing sleeve; the disk-shaped gear is installed on the bearing, the inner side surface of the disk-shaped gear is provided with an upper positioning shoulder, and the disk-shaped gear is connected to the bearing sleeve by screws, so that the bearing is clamped between the lower positioning shoulder and the upper positioning shoulder; the lower specimen replacement block is fixedly connected with the disk-shaped gear through a plurality of positioning pins; the bearing end cover is installed at the open end of the bearing.

[0013] Further, the rotation driving mechanism includes a servo motor, a first bevel gear, a main shaft, a second bevel gear, a coupling and a gear shaft. The servo motor is installed inside the sealed box body; the first bevel gear is installed on the output shaft of the servo motor; the main shaft is vertically installed inside the sealed box body through a bearing seat; the second bevel gear is installed on the main shaft, and the second bevel gear is meshed and connected with the first bevel gear; the main shaft is connected with the gear shaft through the coupling; the columnar gear on the gear shaft is meshed and connected with the disk gear.

[0014] Further, the inner diameter of the sealed cavity is smaller than the inner diameter of the columnar body in the middle of the lower specimen replacement block.

[0015] Further, the gas supply and pressure system includes a helium gas cylinder, a compressed air pipe, a spray gun and a vacuum pump. The helium gas cylinder is connected and communicated with the spray gun through the compressed air pipe; the compressed air pipe extends into the sealed box body so that the spray gun is aligned with the sealing interface.

[0016] Further, the liquid supply and pressure system includes a hydraulic pump, a connecting pipe and a throttle valve. The hydraulic pump is connected and communicated with the sealed cavity through the connecting pipe; the throttle valve is installed on the connecting pipe.

[0017] Further, the sealed box body includes a box body main body and a hatch. The hatch is hinged to the box body main body and connected by a magnetic lock.

[0018] It can be seen from this that the present utility model provides a test machine for testing the sealing performance of a control valve sealing pair. Compared with the prior art, the present utility model has the following beneficial effects:

[0019] 1) It has the dual ability to simultaneously detect liquid and gas leakage and can meet the detection requirements for different leakage amounts of the sealing interface.

[0020] 2) The telescopic rod can adjust the pressure on the sealing interface, simulate the working state of the control valve under different external pressure conditions, and perform sealing performance detection based on this, so as to more comprehensively evaluate the sealing performance of the control valve and improve the accuracy of the detection results.

[0021] 3) The cooperation of the rotation driving mechanism and the rotation lifting assembly can truly simulate the working conditions of a butterfly valve or a ball valve at the moment of opening and closing, providing an important basis for the processing and manufacturing of valve prototypes. Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0023] Figure 1 The attached drawing is a three-dimensional structural schematic diagram of a test machine for testing the sealing performance of a control valve sealing pair provided by the present invention;

[0024] Figure 2 The attached drawing is a front view of a test machine for testing the sealing performance of a control valve sealing pair provided by the present invention;

[0025] Figure 3 The attached drawing is an exploded view of the rotary lifting assembly provided by the present invention;

[0026] Figure 4 The attached drawing is a structural schematic diagram of the lower specimen replacement block provided by the present invention;

[0027] Figure 5 The attached drawing is a structural schematic diagram of the upper specimen replacement block provided by the present invention;

[0028] Figure 6 The attached drawing is a cross-sectional view of the upper specimen replacement block provided by the present invention. Detailed implementation manners

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0030] Such as Figure 1-6As shown in the figure, an embodiment of the present utility model discloses a testing machine for testing the sealing performance of a control valve sealing pair, which includes a sealed box body 1, a rotary drive mechanism 2, a rotary lifting assembly 3, a lower specimen replacement block 4, a telescopic cylinder 5, an upper specimen replacement block 6, a liquid pressure supply system, a gas pressure supply system, a leakage detection system and a data acquisition and control system. A sealed chamber is formed inside the sealed box body 1; the rotary drive mechanism 2 is installed inside the sealed box body 1; the rotary lifting assembly 3 is located inside the sealed box body 1 and is in transmission connection with the rotary drive mechanism 2; the lower specimen replacement block 4 is installed at the top of the rotary lifting assembly 3; the telescopic cylinder 5 is installed inside the sealed box body 1 and its telescopic rod is fixedly connected to the rotary lifting assembly 3 to provide a contact load, and a pressure sensor is equipped at the front end of the telescopic cylinder 5 to monitor the test load in real time; the upper specimen replacement block 6 is installed at the top of the sealed box body 1 and corresponds to the position of the lower specimen replacement block 4. In this embodiment, the upper specimen replacement block 6 is connected to the top of the sealed box body 1 by bolts, and steel gaskets and rubber gaskets are used at the contact between the bolts and the top of the sealed box body 1 to isolate the vibration interaction between the bolts and the metal plate of the sealed box body 1, so as to obtain more accurate test results; the liquid pressure supply system is connected and communicated with the sealing cavity 61 of the upper specimen replacement block 6 to provide pressure fluid for the sealing cavity 61; the gas pressure supply system is aligned with the sealing interface formed between the upper specimen replacement block 6 and the lower specimen replacement block 4; the leakage detection system is electrically connected to the data acquisition and control system, and the output end of the data acquisition and control system is connected to a computer. The present utility model has the dual ability to detect both liquid and gas leakage, can meet the detection requirements for different leakage amounts of the sealing interface, improve the applicability, and at the same time quantify the valve sealing leakage amount to comprehensively evaluate the sealing performance of the control valve.

[0031] Specifically, the lower specimen replacement block 4 is conical. The bottom plane of the lower specimen replacement block 4 is inclined downward from the conical body towards the cone head direction and a leakage hole is provided at the cone head position; the leakage detection system includes a beaker, an electronic balance and a helium mass spectrometer. The beaker is placed inside the sealed box body 1 and is located directly below the leakage hole, so that the leaked liquid can flow smoothly into the beaker for accurate measurement, facilitating the collection of the liquid leaked from the sealing interface; the helium mass spectrometer is connected and communicated with the sealed box body 1; the electronic balance and the helium mass spectrometer are respectively electrically connected to the data acquisition and control system. Before the test starts, the electronic balance needs to be zeroed and calibrated. After the fluid is introduced into the sealing cavity 61 of the upper specimen replacement block 6, under the drive of the pressure, the liquid leaks from the sealing interface to the external environment. The leaked liquid flows through the leakage hole along the inclined plane into the beaker. The electronic balance is used to measure the mass of the beaker before and after the test, and the mass difference is the leakage amount of the sealing interface.

[0032] Specifically, the rotation and lifting assembly 3 includes a base 31, a shaft core 32, a bearing sleeve 33, a bearing 34, a disc gear 35 and a bearing end cover 36. The telescopic rod of the telescopic cylinder 5 is fixedly connected to the base 31. The shaft core 32 is located at the top of the base 31 and is rotatably connected thereto. The bearing sleeve 33 is sleeved on the shaft core 32. The inner side surface of the bearing sleeve 33 is provided with a lower positioning shoulder. The bearing 34 is installed on the shaft core 32 and is located inside the bearing sleeve 33. In this embodiment, the bearing 34 is a deep groove ball bearing, and a soft metal material fitting sleeve is padded on the end face of the inner ring of the deep groove ball bearing for installation on the shaft core 32. The disc gear 35 is installed on the bearing 34. The inner side surface of the disc gear 35 is provided with an upper positioning shoulder. The disc gear 35 is connected to the bearing sleeve 33 by screws, so that the bearing 34 is clamped between the lower positioning shoulder and the upper positioning shoulder. The lower specimen replacement block 4 is fixedly connected to the disc gear 35 by a plurality of positioning pins 37. The bearing end cover 36 is installed at the open end of the bearing 34.

[0033] Specifically, the rotation driving mechanism 2 includes a servo motor 21, a first bevel gear 22, a main shaft 23, a second bevel gear 24, a coupling 25 and a gear shaft 26. The servo motor 21 is installed in the sealed box body 1. The first bevel gear 22 is installed on the output shaft of the servo motor 21. The main shaft 23 is vertically installed in the sealed box body 1 through a bearing seat. The second bevel gear 24 is installed on the main shaft 23. The second bevel gear 24 is meshed and connected with the first bevel gear 22. The main shaft 23 is connected to the gear shaft 26 through the coupling 25. The columnar gear 27 on the gear shaft 26 is meshed with the disc gear 35. When the servo motor 21 is started, the power output by it drives the bevel gear set to rotate. The bevel gear set drives the main shaft 23 to rotate. The main shaft 23 drives the gear shaft 26 to rotate under the connection action of the coupling 25, that is, the columnar gear 27 on the gear shaft 26 rotates, thereby driving the disc gear 35 to rotate. Since the disc gear 35 is matched with the outer ring of the deep groove ball bearing, the friction force during rotation is extremely small. The rotation of the disc gear 35 further drives the lower specimen replacement block 4 connected thereto to rotate.

[0034] Specifically, the height of the columnar gear 27 is greater than the height of the disc gear 35, so that even if the disc gear 35 moves up and down under the action of the telescopic cylinder 5, it still ensures meshing with the columnar gear 27.

[0035] To further optimize the technical solution of the present invention, the inner diameter of the sealing cavity 61 is smaller than the inner diameter of the columnar body in the middle of the lower specimen replacement block 4, which is easy to center.

[0036] Specifically, the gas supply pressure system includes a helium gas cylinder, a compressed air pipe, a spray gun, and a vacuum pump. The helium gas cylinder is connected to the spray gun through the compressed air pipe. In this embodiment, the compressed air pipe is connected to the helium gas cylinder by a quick connector and tightened with a wrench to ensure sealing. The spray gun is provided with a pressure regulator, and the compressed air pipe is connected to the pressure regulator by a quick connector. The compressed air pipe extends into the sealed box body 1 so that the spray gun is aligned with the sealing interface. During operation, the vacuum pump extracts the air in the sealed box body 1 until the required vacuum degree is reached, allows the pressure in the sealed box body 1 to stabilize for a period of time to ensure there is no obvious pressure fluctuation, opens the main valve of the helium gas cylinder to release helium gas, adjusts the pressure of the helium gas through the pressure regulator to make it reach the suitable pressure for spraying. After the helium gas passes through the pressure regulator, it is sprayed onto the sealing interface to be detected through the spray gun, and the reading of the helium mass spectrometer is observed, and the change of the helium concentration detected by the helium mass spectrometer with time is recorded.

[0037] Specifically, the liquid supply pressure system includes a hydraulic pump, a connecting pipe, and a throttle valve. The hydraulic pump is connected to the sealing cavity 61 through the connecting pipe. The throttle valve is installed on the connecting pipe. Of course, to ensure the sealing performance, sealant is applied at the connection between the connecting pipe and the upper specimen replacement block 6 to prevent leakage in the non-measurement area during the test, which may affect the measurement accuracy of the leakage rate. During operation, the hydraulic pump is turned on to pump the pressure fluid into the sealing cavity 61 to discharge the air in the sealing cavity 61. After maintaining the fluid pressure for several minutes, during the pressure holding period, since the sealing interface leaks, the liquid in the sealing cavity 61 will experience a pressure drop. To maintain the test pressure, the fluid needs to be replenished with pressure regularly.

[0038] Specifically, the sealed box body 1 includes a box body main body 11 and a hatch 12. The hatch 12 is hinged to the box body main body 11 and connected by a magnetic lock, which is convenient to open and at the same time ensures good sealing performance. The hatch 12 is made of transparent high-strength material, which not only ensures the strength but also facilitates observing the internal situation. Of course, to ensure the rigidity and stability of the telescopic cylinder 5, a perforated cross plate is provided in the middle of the box body main body 11, and the telescopic rod of the telescopic cylinder 5 penetrates through the perforated cross plate.

[0039] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0040] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A test machine for testing the sealing performance of a control valve sealing pair, characterized in that, It includes a closed box, a rotary drive mechanism, a rotary lifting assembly, a lower sample replacement block, a telescopic cylinder, an upper sample replacement block, a liquid pressure supply system, a gas pressure supply system, a leakage detection system and a data acquisition and control system, wherein the rotary drive mechanism is installed inside the closed box; the rotary lifting assembly is located inside the closed box and is transmission-connected to the rotary drive mechanism; the lower sample replacement block is installed on the top of the rotary lifting assembly; the telescopic cylinder is installed inside the closed box and its telescopic rod is fixedly connected to the rotary lifting assembly; the upper sample replacement block is installed on the top of the closed box and corresponds to the position of the lower sample replacement block; the liquid pressure supply system is connected to the sealed cavity of the upper sample replacement block; the gas pressure supply system is aligned with the sealing interface formed between the upper sample replacement block and the lower sample replacement block; and the leakage detection system is electrically connected to the data acquisition and control system.

2. The sealing performance testing machine for a control valve sealing pair according to claim 1, wherein The lower sample replacement block is conical in shape, and the bottom plane of the lower sample replacement block is inclined downward from the conical body toward the cone head and a leakage hole is opened at the cone head; the leakage detection system includes a beaker, an electronic balance and a helium mass spectrometer, the beaker is placed inside the closed box and is located directly below the leakage hole; the helium mass spectrometer is connected to the closed box; the electronic balance and the helium mass spectrometer are electrically connected to the data acquisition and control system respectively.

3. The sealing performance testing machine for the sealing pair of a control valve according to claim 1, characterized in that, The rotary lifting assembly includes a base, an axis core, a bearing sleeve, a bearing, a disc gear and a bearing end cover, the telescopic rod of the telescopic cylinder is fixedly connected to the base; the axis core is located at the top of the base and is rotatably connected thereto; the bearing sleeve is sleeved on the axis core; a lower positioning shoulder is provided on the inner side of the bearing sleeve; the bearing is mounted on the axis core and located inside the bearing sleeve; the disc gear is mounted on the bearing, and an upper positioning shoulder is provided on the inner side of the disc gear, the disc gear and the bearing sleeve are connected by screws so that the bearing is clamped between the lower positioning shoulder and the upper positioning shoulder; the lower sample replacement block is fixedly connected to the disc gear by a plurality of positioning pins; the bearing end cover is mounted on the open end of the bearing.

4. The sealing performance testing machine for the sealing pair of a control valve according to claim 3, characterized in that The rotary drive mechanism includes a servo motor, a first bevel gear, a main shaft, a second bevel gear, a coupling and a gear shaft. The servo motor is installed in the closed housing; the first bevel gear is installed on the output shaft of the servo motor; the main shaft is vertically installed in the closed housing through a bearing seat; the second bevel gear is installed on the main shaft, and the second bevel gear is meshed and connected with the first bevel gear; the main shaft is connected to the gear shaft through the coupling; the columnar gear on the gear shaft is meshed and connected with the disc gear.

5. A sealing performance testing machine for a control valve sealing pair according to claim 1, characterized in that The inner diameter of the sealed cavity is smaller than the inner diameter of the central columnar body of the lower sample replacement block.

6. A sealing performance testing machine for a control valve sealing pair according to claim 1, characterized in that The gas pressure supply system includes a helium cylinder, a compressed air pipe, a spray gun and a vacuum pump. The helium cylinder is connected to the spray gun through the compressed air pipe; the compressed air pipe extends into the closed box so that the spray gun is aligned with the sealing interface.

7. A sealing performance testing machine for a control valve sealing pair according to claim 1, characterized in that, The liquid supply pressure system includes a hydraulic pump, a connecting pipeline, and a throttle valve. The hydraulic pump is connected and communicated with the sealed cavity through the connecting pipeline; the throttle valve is installed on the connecting pipeline.

8. A sealing performance testing machine for a control valve sealing pair according to claim 1, characterized in that, The sealed box body includes a box body main body and a hatch door. The hatch door is hinged to the box body main body and connected by a magnetic lock.

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