A valve airtightness testing device and control method

Abstract

This application relates to a valve airtightness testing device and control method. The valve airtightness testing device includes a base and a sealing assembly with a differential sealing unit. The differential sealing unit forms a pressure compensation chamber through an outer bearing seat and an inner floating sealing disc. High-pressure medium is introduced via a through-pass air passage, and the pressure-bearing area within the inner floating sealing disc cavity is larger than the pressure-bearing area at the valve port abutment end. This valve airtightness testing device utilizes the net thrust generated by the medium on the area difference to drive the sealing disc to automatically press against the valve port, achieving a self-locking seal. It eliminates the need for externally applied large axial clamping force, effectively solving the problems of false sealing and detection distortion caused by valve body deformation due to external loads. It achieves near-real-world testing without forced stress interference, avoiding physical damage to the valve body and precision components.

Description

Technical Field

[0001] This invention relates to an airtightness testing device, and more particularly to a valve airtightness testing device and control method. Background Technology

[0002] In the field of industrial fluid control, high-pressure valves (such as fixed ball valves and gate valves) are key shut-off components in pipeline systems. Their pressure resistance and sealing performance testing before leaving the factory is a core aspect of ensuring industrial safety. According to the standards for valves in the oil and gas industry, valves must undergo pressure testing strictly according to a specific sequence and condition. The integrity principle explicitly requires that the shell test and high-pressure sealing test must be performed with the valve fully assembled. The standard also stipulates a disassembly failure principle: if the valve is disassembled after passing the pressure test (e.g., to avoid damage by opening both ends for installation or replacement of the valve seat), the previous test results automatically become invalid, and the test must be repeated to ensure that the assembly preload, bolt torque, and the mating positions of all components in the final delivered product meet the requirements of actual operating conditions.

[0003] Existing valve airtightness testing typically employs a horizontal hydraulic valve test bench. A typical structure of this type of device includes a frame, a hydraulic system, and two rigid sealing blind flanges positioned opposite each other. During testing, to prevent the high-pressure test medium from forcibly dislodging the blind flanges, the hydraulic system must apply a significant axial clamping force to the sealing blind flanges, typically 1.1 to 1.5 times the pressure of the test medium. In other words, external mechanical force is used to forcibly press the blind flanges against the valve flange end faces, achieving a passive seal at the ports using O-rings or other sealing elements. Subsequently, high-pressure gas or liquid is injected into the valve body through air passages created on the blind flanges for a pressure holding test.

[0004] However, existing technologies may suffer from detection distortion in practical applications. First, the enormous axial clamping force applied to counteract the high-pressure medium forces the valve body to undergo slight elastic deformation, resulting in micro-axial deformation. In precision-fitted structures such as fixed ball valves, this deformation is transmitted through the valve body and forcibly compresses the internal floating valve seat assembly, causing abnormal high-pressure contact between the valve seat and the ball. This forced contact easily fills in any existing tiny scratches or defects on the sealing surface, leading to a false seal phenomenon—that is, the test shows as qualified, but leakage occurs in actual pipeline conditions (without axial clamping force). Second, to avoid damage to the sealing pair from the clamping force, existing technologies have attempted to remove the internal valve seat for shell testing. However, this not only directly violates the standard regulations for whole-machine testing, but also, conducting high-pressure testing without valve seat support, easily causes irreversible plastic deformation of the precision sealing gland holes and spring grooves inside the valve body due to high-pressure turbulent impact or stress concentration, resulting in permanent damage. Therefore, the industry urgently needs a detection device and control method that can eliminate the interference of external mechanical clamping loads on internal sealing pairs without disassembling the whole machine or violating standards. Summary of the Invention

[0005] The purpose of this invention is to provide a valve airtightness testing device and control method that can eliminate the interference of external mechanical clamping load on the internal sealing pair without disassembling the whole machine or violating standards.

[0006] The technical solution adopted by the present invention to solve the above problems is: a valve airtightness testing device, comprising:

[0007] Base;

[0008] Two sealing components are disposed on the base and arranged opposite to each other, and the two sealing components are configured to move in a controlled manner toward the two symmetrical valve ports on either side of the valve to be tested, one closer to and one further away from the valve.

[0009] A differential sealing unit disposed on the sealing assembly, the differential sealing unit comprising:

[0010] An external support seat is connected to the sealing assembly. The external support seat has a receiving cavity inside, and a first air passage communicating with the receiving cavity is opened on the external support seat.

[0011] An inner floating sealing disc is slidably disposed within the outer bearing seat. The inner floating sealing disc is sealed and fitted within the receiving cavity. The side of the inner floating sealing disc near the sealing assembly forms a pressure compensation cavity with the inner wall of the receiving cavity. The pressure compensation cavity is connected to an external high-pressure air source through the first air passage. The inner floating sealing disc is provided with a second air passage that extends through its own axial direction. The inner floating sealing disc is at least partially located outside the outer bearing seat.

[0012] Wherein, the central axes of the two inner floating sealing discs are collinear; and the first effective pressure-bearing area of ​​the inner floating sealing disc located in the pressure compensation chamber is greater than the second effective pressure-bearing area of ​​the end face of the inner floating sealing disc located outside the outer bearing seat for contacting the valve port of the valve under test; when the valve airtightness testing device is configured such that when an external high-pressure air source injects high-pressure medium into the pressure compensation chamber through the first air passage and the second air passage, the net thrust generated by the difference between the first effective pressure-bearing surface and the second effective pressure-bearing surface drives the inner floating sealing disc to extend outward from the outer bearing seat and press against the valve port of the valve under test.

[0013] Preferably, the inner wall of the receiving cavity of the outer bearing seat is provided with a groove along its own axial direction, the inner floating sealing disc has a stepped piston-shaped structure, the large-diameter end of the piston-shaped structure is slidably sealed in the groove, and the small-diameter end of the piston-shaped structure extends to the outside of the outer bearing seat; and a sealing component is provided at the fitting gap between the inner floating sealing disc and the outer bearing seat.

[0014] Preferably, the base has two symmetrically arranged fixing seats, each of the sealing components is disposed on each of the fixing seats, and a guide shaft is provided between the two fixing seats, the axial direction of the guide shaft being parallel to the moving direction of the sealing component; the sealing drive component includes:

[0015] A sliding member is slidably disposed on the guide shaft, and the sliding member is connected to the outer bearing seat;

[0016] A controlled-movement drive rod, the direction of movement of the drive rod being parallel to the axial direction of the guide shaft, the drive rod being connected to the outer support seat to drive the outer support seat to move along the guide shaft.

[0017] Preferably, the end face of the inner floating sealing disc extending to the outside of the outer bearing seat is constructed as a convex arc-shaped contact surface. The outer diameter of the convex arc-shaped contact surface is larger than the inner diameter of the valve port to be tested, and it is configured such that when it abuts against the valve port to be tested, the normal force at the contact point of the two points points towards the axis of the inner floating sealing disc.

[0018] Preferably, the valve airtightness testing device is characterized by further comprising:

[0019] An attitude adjustment mechanism is disposed on the base, the attitude adjustment mechanism comprising:

[0020] Multi-axis adjustment assembly, including output end;

[0021] A mounting plate disposed at the output end of the multi-axis adjustment assembly is used to support the valve to be tested.

[0022] A pressure sensing array, comprising a pressure sensor, is disposed on the convex arc-shaped contact surface of the inner floating sealing disc.

[0023] The multi-axis adjustment component is configured to support the valve under test and drive the valve under test to perform multi-degree-of-freedom displacement and deflection in space.

[0024] The control unit is connected to the contact pressure sensing array and the multi-axis adjustment assembly respectively, and is configured to control the movement of the output end of the multi-axis adjustment assembly according to the pressure distribution difference fed back by the contact pressure sensing array, so as to adjust the posture of the valve under test until the central axis of the valve under test coincides with the central axis of the inner floating sealing discs on both sides.

[0025] Preferably, the contact pressure sensing array includes at least four pressure sensors, which are evenly spaced in a ring along the circumference of the convex arc-shaped contact surface; the pressure sensors are installed in such a way that when the inner floating sealing disc abuts against the valve port of the valve under test, the sensing surface of the pressure sensor is exactly in contact with the chamfered edge of the valve port of the valve under test.

[0026] Preferably, the pressure sensor is a thin-film pressure sensor or a miniature piezoelectric sensor, and is embedded in the surface of the inner floating sealing disc. The sensing surface of the pressure sensor is not higher than the contour surface of the convex arc-shaped contact surface.

[0027] Preferably, the multi-axis adjustment mechanism is a six-degree-of-freedom parallel adjustment platform or a series-superimposed multi-dimensional moving platform; the mounting plate is provided with a V-shaped adaptive seat or bolt fastening interface for positioning the valve to be tested.

[0028] Preferably, the control unit is configured to control the output end of the multi-axis adjustment component to move the valve on the mounting plate when the difference in readings of the sensors in the relatively symmetrical positions of the contact pressure sensing array exceeds a preset threshold, until the central axis of the valve under test is collinear with the central axis of the inner floating sealing discs on both sides.

[0029] Specifically, a control method for the above-mentioned valve airtightness testing device includes the following steps:

[0030] Place the valve to be tested on the mounting plate at the output end of the multi-axis adjustment assembly, and drive the two sealing assemblies to move toward the valve to be tested until the convex arc-shaped contact surfaces of the two inner floating sealing discs fit against the valve port of the valve to be tested.

[0031] Based on the data from the contact pressure sensor array on the inner floating sealing disc, the force eccentricity vector is determined, and the output end of the multi-axis adjustment component is moved according to the force eccentricity vector to drive the valve under test on the mounting plate to adjust its spatial posture until the values ​​of each pressure sensor are within the balance range, thereby achieving the collinearity of the central axis of the valve under test and the central axis of the inner floating sealing disc.

[0032] Lock the position of the output end on the multi-axis adjustment assembly, and inject high-pressure test medium into the first air passage of the outer bearing seat; use the area difference between the first effective pressure-bearing surface and the second effective pressure-bearing surface to generate a self-sealing force that increases with pressure, and complete the high-pressure airtightness test of the valve.

[0033] After the test is completed, the high-pressure medium is released, the inner floating sealing disc retracts under the action of the reset force, the sealing assembly returns to its original position, and is removed from the valve.

[0034] The beneficial effects of the embodiments of the present invention are as follows:

[0035] 1. Due to the adoption of a differential sealing unit on the sealing assembly, a pressure compensation chamber is formed by the cooperation of the outer bearing seat and the inner floating sealing disc. The first and second air passages connect the external high-pressure air source simultaneously to the pressure compensation chamber and the interior of the valve under test. Furthermore, a special design ensures that the first effective pressure-bearing area of ​​the inner floating sealing disc within the pressure compensation chamber is larger than its second effective pressure-bearing area at the end abutting the valve under test. Therefore, the net thrust generated by the high-pressure medium entering the pressure compensation chamber due to the area difference can drive the inner floating sealing disc to automatically extend and press against the valve port to achieve a self-locking seal, eliminating the need for external mechanical structures to apply pressure far exceeding the test pressure. The immense axial clamping force of the pressure effectively solves the technical problem in existing technologies where excessive external axial loads are applied to resist high-pressure media, forcing the valve body to undergo elastic deformation. This leads to abnormal forced contact of the internal sealing pair, masking actual leakage defects and causing false sealing and detection distortion. Thus, it provides a near-real-world airtightness testing environment for the valve under test, eliminating external forced stress interference, while strictly adhering to the whole machine testing standards and without disassembling the valve seat. This significantly improves the fidelity and accuracy of the test results in reflecting the actual operating conditions of the pipeline, while avoiding irreversible physical damage to the valve body and precision sealing components caused by the high-pressure testing process.

[0036] 2. By employing a technique that extends the inner floating seal disc to the outside of the outer bearing seat with a convex arc-shaped contact surface, and configuring the normal force at the contact point to point towards the axis of the inner floating seal disc when it comes into contact with the valve under test, the technical problem of valve body instability, overturning, or uneven contact of the sealing surface caused by the high-pressure sealing force generating an eccentric overturning torque when using a differential floating seal structure for testing is solved. This is achieved by utilizing the geometric self-aligning characteristics of the convex arc fit, ensuring that the line of action of the contact reaction force always passes through the main force axis to eliminate the overturning torque, and generating a radial recovery component force that causes the valve body to automatically return to its correct position. This ensures the self-stability of the valve body posture and the sealing reliability of the device under floating conditions without rigid mechanical clamping.

[0037] 3. Based on the differential media self-tightening and the convex arc geometric self-alignment of the inner floating seal disc end face, this device further employs an attitude adjustment mechanism on the base, including a multi-axis adjustment component and a mounting plate. A pressure sensor array is arranged on the convex arc contact surface of the inner floating seal disc. The control unit uses a closed-loop control system based on the pressure distribution difference feedback from the sensor array to drive the multi-axis adjustment component to perform spatial multi-degree-of-freedom displacement and deflection compensation of the valve under test. Therefore, this effectively solves the technical problem of insufficient geometric self-resetting torque to overcome support resistance or friction when passive alignment is performed solely on the convex arc surface. This can lead to valve port force eccentricity, alignment failure, or even valve body overturning under pressure. This achieves active and accurate perception and intelligent closed-loop correction of the valve's spatial attitude, ensuring a high degree of overlap between the valve body's central axis and the inner floating seal disc's central axis under stress-free testing conditions. This significantly improves the device's adaptability to valves of different specifications and the safety of the high-pressure testing process. Attached Figure Description

[0038] Figure 1 This is a schematic front sectional view of a valve body airtightness testing device according to an embodiment of the present invention.

[0039] Figure 2 This is a schematic structural diagram of an internal floating sealing disc according to an embodiment of the present invention.

[0040] Figure 3 This is a schematic structural diagram of an attitude adjustment mechanism according to an embodiment of the present invention.

[0041] Figure 4 This is a schematic structural diagram of a valve body airtightness testing device according to an embodiment of the present invention.

[0042] Figure 5 This is a flowchart illustrating a control method for a valve body airtightness detection device according to an embodiment of the present invention.

[0043] The components are as follows: 1. Base; 2. Sealing assembly; 210. Sliding element; 220. Drive rod; 3. Differential sealing unit; 310. Outer bearing seat; 311. Receiving cavity; 312. First air passage; 313. Slide groove; 320. Inner floating sealing disc; 321. Second air passage; 322. Convex arc-shaped contact surface; 330. Sealing assembly; 340. Elastic reset element; 4. Pressure compensation cavity; 5. Fixed seat; 6. Guide shaft; 7. Attitude adjustment mechanism; 710. Multi-axis adjustment assembly; 711. Output end; 720. Mounting plate; 730. Pressure sensor array; 731. Pressure sensor. Detailed Implementation

[0044] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0045] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0047] The typical structure of an existing horizontal hydraulic valve test bench includes a frame, a hydraulic system, and two rigid sealing blind plates arranged oppositely. During the test, in order to prevent the high-pressure test medium from pushing open the blind plates at both ends, the hydraulic system must apply a huge axial clamping force to the sealing blind plates, that is, use an external mechanical force to forcibly press the blind plates against the valve flange end face, and achieve passive sealing of the ports through seals such as O-rings. Subsequently, high-pressure gas or liquid is injected into the valve body through the gas path opened on the blind plate for pressure-holding testing.

[0048] During the process of using the existing horizontal hydraulic valve test bench to conduct airtightness detection on the valve, the huge axial clamping force applied to counteract the high-pressure medium will force the valve body to undergo slight elastic deformation. In a fixed ball valve, which is a valve with a floating valve seat, this elastic deformation will be transmitted through the valve body and forcibly compress the internal floating valve seat assembly, causing an abnormal forced fit between the valve seat and the sphere, which is extremely likely to cause false sealing of the originally existing tiny scratches or defects on the sealing surface, that is, it shows qualified on the test bench, but leaks under the actual pipeline (without axial clamping force) working conditions. And it should be noted that if one tries to first remove the internal valve seat and then conduct airtightness testing on the shell, this not only violates the standard regulations regarding the whole machine test, but also, when conducting high-pressure testing without the support of the valve seat, it is extremely likely that the precision sealing gland holes and spring grooves inside the valve body will undergo irreversible plastic deformation due to high-pressure turbulent impact or stress concentration, causing permanent damage.

[0049] Therefore, this application proposes a valve body airtightness detection device that can eliminate the interference of external mechanical clamping loads on the internal sealing pair without disassembling the whole machine and without violating the standards.

[0050] Figure 1 is a schematic front cross-sectional view of the valve body airtightness detection device shown in an embodiment of the present invention; Figure 2 is a schematic structural diagram of the inner floating sealing disc 320 shown in an embodiment of the present invention; Figure 4 is a schematic structural diagram of the valve body airtightness detection device shown in an embodiment of the present invention. Please refer to Figure 1 、 Figure 2 and Figure 4The valve airtightness testing device includes a base 1, two sealing components 2 disposed on the base 1 and arranged opposite to each other, and a differential sealing unit 3 disposed on the sealing components 2. The two sealing components 2 are configured to move in a controlled manner toward or away from the valve ports on both sides of the valve under test. The differential sealing unit 3 includes an outer support seat 310 connected to the sealing component 2 and an inner floating sealing disc 320 slidably disposed within the outer support seat 310. The outer support seat 310 has a receiving cavity 311 inside, and a first air passage 312 communicating with the receiving cavity 311 is provided on the outer support seat 310. The inner floating sealing disc 320 is sealed and fitted within the receiving cavity 311. The side of the inner floating sealing disc 320 near the sealing component 2 and the inner wall of the receiving cavity 311 enclose a pressure compensation cavity 4, and the pressure compensation cavity 4 is connected to an external high-pressure air source through the first air passage 312. The inner floating sealing disc 320 is provided with a second air passage 321 penetrating its own axial direction. The inner floating sealing disc 320 is at least partially located outside the outer support seat 310. Wherein, the central axes of the two inner floating sealing discs 320 are collinear; and the first effective pressure-bearing area of ​​the inner floating sealing disc 320 located in the pressure compensation chamber 4 is greater than the second effective pressure-bearing area of ​​the end face of the inner floating sealing disc 320 located outside the outer bearing seat 310 for contacting the valve port of the valve under test; the valve airtightness testing device is configured such that when an external high-pressure air source injects high-pressure medium into the pressure compensation chamber 4 through the first air passage 312 and the second air passage 321, the net thrust generated by the difference between the first effective pressure-bearing area and the second effective pressure-bearing area drives the inner floating sealing disc 320 to extend outward from the outer bearing seat 310 and press against the valve port of the valve under test.

[0051] Specifically:

[0052] The base 1, serving as the supporting foundation for the entire device, is typically made of high-strength, rigid material to withstand gravity and reaction forces during the testing process. Two sealing components 2 are arranged opposite each other on the base 1, with their axes of movement coinciding. The sealing components 2 are configured as controlled motion mechanisms, capable of moving towards or away from the valve ports on either side of the valve under test. This movement function is primarily used for initial positioning of the device and retraction after testing, and can be achieved, for example, through screw drive, hydraulic drive, or pneumatic slide, with the aim of delivering the sealing unit to the vicinity of the valve port under test.

[0053] The core differential sealing unit 3 is located at the end of the aforementioned sealing assembly 2. The differential sealing unit 3 mainly consists of two parts: an outer bearing seat 310 and an inner floating sealing disc 320. The two parts are slidably fitted together to form a structure similar to that of a piston and a cylinder.

[0054] The outer support seat 310 is fixedly connected to the sealing assembly 2, serving as the base for force bearing and guidance. The outer support seat 310 has a hollow receiving cavity 311 machined inside. This receiving cavity 311 is typically a cylindrical inner hole, and its inner wall is precision machined to ensure sealing performance. A first air passage 312 is provided on the side wall or rear end face of the outer support seat 310. This first air passage 312 directly penetrates the internal receiving cavity 311 for introducing external high-pressure media.

[0055] The inner floating sealing disc 320 is slidably disposed within the receiving cavity 311 of the outer support seat 310. A sealing fit (such as installing a sealing ring) is provided between the outer peripheral surface of the inner floating sealing disc 320 and the inner wall of the receiving cavity 311 to ensure airtightness. Structurally, the side of the inner floating sealing disc 320 closest to the sealing assembly 2 (i.e., the side located deep within the receiving cavity 311) and the inner wall of the receiving cavity 311 together form a variable-volume enclosed space, namely the pressure compensation cavity 4. This pressure compensation cavity 4 is directly connected to an external high-pressure air source through the aforementioned first air passage 312.

[0056] The inner floating sealing disc 320 is not completely hidden within the outer bearing seat 310; at least a portion (the front end) extends to the outside of the outer bearing seat 310. This extended end face is designed as a sealing surface for direct contact with the valve port of the valve under test. Furthermore, a second air passage 321, extending axially through the entire disc body, is axially formed at the center of the inner floating sealing disc 320. The function of this second air passage 321 is to further guide the medium within the pressure compensation chamber 4 into the interior of the valve under test, thereby achieving simultaneous single air source and bidirectional charging.

[0057] The valve airtightness testing device in this embodiment follows the differential area principle. That is, the force-bearing surface (first effective pressure-bearing area) of the inner floating sealing disc 320 located in the pressure compensation chamber 4 is numerically designed to be larger than the force-bearing surface (second effective pressure-bearing area) of its end face located outside the outer bearing seat 310 and used to contact and abut with the valve port of the valve under test. This area difference is the basis for realizing the self-tightening function of the medium.

[0058] The operation procedure of the valve airtightness testing device is as follows:

[0059] First, the two sealing assemblies 2 on the control base 1 move towards the center, causing the differential sealing units 3 on both sides to approach the valve under test. The sealing assemblies 2 continue to move until the outer end face of the inner floating sealing disc 320 gently contacts or maintains a small gap with the valve ports on both sides of the valve under test. At this time, the valve airtightness testing device only provides a positioning function and does not apply a huge axial mechanical clamping force.

[0060] When the external high-pressure gas source is activated, the high-pressure test medium (such as nitrogen or compressed air) first enters the pressure compensation chamber 4 through the first air passage 312 on the external bearing seat 310.

[0061] The high-pressure medium entering the pressure compensation chamber 4 fills the chamber and acts on the first effective pressure-bearing area of ​​the inner floating seal disc 320. Simultaneously, the medium passes through the second air passage 321 penetrating the inner floating seal disc 320 and directly enters the internal cavity of the valve under test, acting on the valve's inner wall and the second effective pressure-bearing area where the inner floating seal disc 320 contacts the valve. At this time, the pressure compensation chamber 4 and the interior of the valve under test are actually in a connected state, and the pressure values ​​remain dynamically balanced.

[0062] Because the first effective pressure-bearing area of ​​the inner floating sealing disc 320 inside the pressure compensation chamber 4 is greater than its second effective pressure-bearing area on the valve port contact side, under the same medium pressure, the outward thrust acting on the inner side is always greater than the inward counter-thrust acting on the outer side. The difference between these two forces forms a net thrust pointing towards the valve under test.

[0063] Driven by the net thrust, the inner floating sealing disc 320 slides outward relative to the outer bearing seat 310 and presses tightly against the valve port of the valve under test with a force proportional to the test pressure, forming a reliable end face seal. As the test pressure increases, the clamping force automatically increases to prevent leakage; conversely, as the pressure decreases, the clamping force decreases accordingly.

[0064] After the pressure holding test is completed, the high-pressure medium is released, the net thrust disappears, and the sealing component 2 drives the sealing unit to retract, completing the testing process.

[0065] The valve airtightness testing device in this embodiment is particularly suitable for factory airtightness testing of pressure-sensitive, precision-structured high-pressure industrial valves (such as fixed ball valves and flat gate valves). It is suitable for applications requiring high-precision simulation of actual pipeline operating conditions, especially in scenarios where traditional hydraulic test benches can easily cause valve body deformation, leading to distorted test results. This device requires a stable external high-pressure air source, and the flange faces at both ends of the valve under test must have a certain degree of flatness to accommodate the contact of the internal floating sealing disc 320.

[0066] This embodiment employs a differential sealing unit 3 on the sealing assembly 2, forming a pressure compensation chamber 4 through the cooperation of the outer bearing seat 310 and the inner floating sealing disc 320. The first air passage 312 and the second air passage 321 connect an external high-pressure air source simultaneously to the pressure compensation chamber 4 and the interior of the valve under test. Furthermore, a special configuration ensures that the first effective pressure-bearing area of ​​the inner floating sealing disc 320 within the pressure compensation chamber 4 is larger than its second effective pressure-bearing area at the point of contact with the valve under test. Therefore, the net thrust generated by the high-pressure medium entering the pressure compensation chamber 4 due to the area difference can drive the inner floating sealing disc 320 to automatically extend and press against the valve port to achieve a self-locking seal, eliminating the need for external... The mechanical structure applies a huge axial clamping force far exceeding the test pressure, effectively solving the technical problem in existing technologies where excessive external axial loads are applied to resist high-pressure media, forcing the valve body to undergo elastic deformation, which in turn leads to abnormal forced contact of the internal sealing pair, masking real leakage defects and causing false sealing and detection distortion. This achieves a near-real-world airtightness testing environment for the valve under test, eliminating external forced stress interference, while strictly adhering to the whole machine testing standards and without disassembling the valve seat. This significantly improves the reproduction and accuracy of the test results to the actual operating conditions of the pipeline, while avoiding irreversible physical damage to the valve body and precision sealing components 330 caused by the high-pressure testing process.

[0067] Please see Figure 1 and Figure 2 Furthermore, in some embodiments, the inner wall of the receiving cavity 311 of the outer support seat 310 is provided with a groove 313 along its own axial direction, the inner floating sealing disc 320 has a stepped piston-like structure, the large-diameter end of the piston-like structure is slidably sealed in the groove 313, and the small-diameter end of the piston-like structure extends to the outside of the outer support seat 310; and a sealing assembly 330 is provided at the fitting gap between the inner floating sealing disc 320 and the outer support seat 310.

[0068] In this embodiment, the internal fitting structure of the differential sealing unit 3 has been specifically optimized. The outer bearing seat 310 is not a simple hollow cylinder; the inner wall of its internal receiving cavity 311 is precision machined, and a section of guide and pressure-bearing groove 313 is opened along its own axial direction. This groove 313 is usually constructed as a high-precision cylindrical inner hole, serving as a track for moving parts.

[0069] The inner floating sealing disc 320, which works in conjunction with the inner floating sealing disc 320, is geometrically constructed as a stepped piston-like structure. This structure has a distinct cross-sectional change, consisting of a large-diameter end and a small-diameter end. The large-diameter end is located on the rear side of the inner floating sealing disc 320 (i.e., the side closest to the sealing assembly 2), and its outer diameter forms a precise clearance fit with the inner diameter of the inner groove 313 on the inner wall of the outer support seat 310, allowing the large-diameter end to slide and seal within the groove 313. The small-diameter end is located on the front side of the inner floating sealing disc 320, with a smaller diameter than the large-diameter end, and is designed to extend to the outside of the outer support seat 310 for direct contact with the valve under test. At the transition between the large-diameter end and the small-diameter end, an axial stepped surface is naturally formed.

[0070] To ensure the airtightness of the high-pressure medium during the driving process, a high-performance sealing component 330 is provided at the mating gap between the inner floating seal disc 320 and the outer support seat 310. Specifically, the sealing component 330 is typically installed in an annular sealing groove on the outer circumference of the large-diameter end of the inner floating seal disc 320, or in a sealing groove on the inner wall of the sliding groove 313 of the outer support seat 310. The sealing component 330 can be a Glyd ring, a Step seal, or a high-pressure resistant combination sealing ring to meet the requirements of dynamic sliding seals.

[0071] In practical applications, this stepped piston-like structure serves a dual purpose: guiding and bearing pressure.

[0072] When the high-pressure medium enters the outer bearing seat 310, the large-diameter end of the inner floating sealing disc 320 is pushed by the medium pressure within the groove 313. Because the groove 313 restricts the radial displacement of the sealing disc, the large-diameter end can only reciprocate axially within the groove 313, acting as a piston. At this time, the sealing assembly 330, located at the mating clearance, is tightly attached to the inner wall of the groove 313, strictly isolating the pressure space behind the large-diameter end from the external environment in front, preventing leakage of the driving medium.

[0073] As pressure builds up, the small-diameter end of the inner floating seal 320 extends from the outer bearing seat 310 like a piston rod. This stepped structural design allows the inner floating seal 320 to physically distinguish between the rear driving force-bearing surface (large-diameter end section) and the front working contact surface (small-diameter end section), ensuring that the driving force can be stably transmitted through the robust large-diameter end to the small-diameter end extending outward.

[0074] In one alternative embodiment, to further improve guiding accuracy, a guide wear-resistant ring can be provided on the outer circumferential surface of the large-diameter end of the stepped piston-like structure to avoid direct metal-to-metal contact. Furthermore, the stepped transition can be designed as a smooth conical transition or a rounded corner transition to reduce stress concentration.

[0075] In this embodiment, by employing the technical means of designing the inner wall of the outer bearing seat 310 as an axial groove 313, designing the inner floating sealing disc 320 as a stepped piston-like structure, and setting a sealing component 330 at the large-diameter end fitting gap, the natural cross-sectional difference formed by the stepped structure provides a stable physical basis for differential force. At the same time, the cooperation between the groove 313 and the large-diameter end achieves high-precision axial guidance, effectively solving the technical problems in the prior art where a single flat sealing structure is prone to radial shaking and sealing failure when under pressure and movement, and where the driving medium is prone to internal leakage during dynamic processes. Thus, the smooth movement of the inner floating sealing disc 320 when outputting huge axial thrust and the absolute airtightness of the driving chamber are achieved, ensuring the stable output of the self-tightening sealing force.

[0076] Please see Figure 1 Furthermore, in some embodiments, the base 1 is provided with two symmetrically arranged fixed seats 5, each of the sealing components 2 is disposed on each of the fixed seats 5, and a guide shaft 6 is provided between the two fixed seats 5. The axial direction of the guide shaft 6 is parallel to the moving direction of the sealing component 2. The sealing component 2 includes a sliding member 210 slidably disposed on the guide shaft 6 and a controlled moving drive rod 220, wherein the sliding member 210 is connected to the outer support seat 310, the moving direction of the drive rod 220 is parallel to the axial direction of the guide shaft 6, and the drive rod 220 is connected to the outer support seat 310 to drive the outer support seat 310 to move along the guide shaft 6.

[0077] Specifically:

[0078] In this embodiment, the support and drive guide structure of the valve airtightness testing device has been specially optimized. The base of the device is a robust base 1, which is usually made of high-strength cast iron or welded from thickened steel plate. It undergoes aging treatment to eliminate internal stress and ensures that it will not deform when bearing heavy valves and high-pressure test reaction forces for a long time.

[0079] On the upper surface of the base 1, two symmetrically arranged fixing seats 5 are provided. These two fixing seats 5 are firmly installed at both ends of the base 1 like a gantry or support. Their bottoms can be connected to the base 1 by high-strength bolts or directly welded to form a stable static support point. Between these two fixing seats 5, one or more guide shafts 6 are arranged transversely. The guide shafts 6 are usually made of alloy steel cylinders with chrome-plated hardening and precision grinding treatment, which have extremely high straightness and surface finish. The two ends of the guide shafts 6 are respectively embedded or fixed to the inner side of the two fixing seats 5, and the axial direction of the guide shafts 6 is strictly parallel to the preset movement trajectory of the sealing component 2.

[0080] The sealing assembly 2 is designed to slide along the aforementioned guide shaft 6. Specifically, the sealing assembly 2 comprises two parts: a slider 210 and a drive rod 220. The slider 210 is constructed as a slider or sleeve structure with a through hole, and is internally fitted with a precision linear bearing or a self-lubricating copper sleeve. The slider 210 is fitted onto the guide shaft 6 and forms a precision clearance fit with the guide shaft 6, thereby restricting all degrees of freedom except for axial movement. The other side of the slider 210 is rigidly connected to the outer support seat 310 (e.g., fastened by a flange or screws), so that the outer support seat 310 is suspended on the guide shaft 6.

[0081] The driving force is provided by a controlled-movement drive rod 220. This drive rod 220 is typically the piston rod of a hydraulic cylinder or the output shaft of an electric actuator, with its power source (such as a cylinder body or motor) mounted inside or behind the fixed base 5. The direction of movement of the drive rod 220 is precisely calibrated to maintain a high degree of parallelism with the axis of the guide shaft 6. The end of the drive rod 220 is fixedly connected to the center or center of gravity of the outer support seat 310 for directly transmitting push and pull forces.

[0082] In actual operation, the valve airtightness testing device clearly separates and coordinates the driving force and guiding function.

[0083] When the control system issues a feed command, the power source drives the drive rod 220 to extend. The drive rod 220 applies a thrust to the connected outer support seat 310 along the axial direction. Since the outer support seat 310 is connected to the sliding member 210, and the sliding member 210 is constrained by the guide shaft 6, the outer support seat 310 can only move smoothly along the straight trajectory defined by the guide shaft 6.

[0084] During this process, the guide shaft 6 bears the entire weight of the outer support seat 310 and the subsequent sealing unit, as well as any potential lateral overturning moment, ensuring that the drive rod 220 only bears axial load and preventing bending of the drive rod 220 or wear of the seals due to radial force. When the drive rod 220 retracts, it drives the outer support seat 310 to smoothly return to its initial position along the same trajectory. The bearings or bushings inside the sliding member 210 significantly reduce frictional resistance during movement, eliminating low-speed crawling.

[0085] In one alternative embodiment, the guide shaft 6 can be replaced with a linear guide pair with a rectangular cross-section, and the slider 210 can be replaced with a ball bearing slider to withstand greater lateral torque. In another alternative, to increase stability, two guide shafts 6 can be arranged in parallel between the two fixed seats 5, with the slider 210 designed as a double-hole structure that fits onto both shafts simultaneously. The drive rod 220 is arranged on the geometric center line of the two guide shafts 6 to achieve absolute centering of the thrust.

[0086] In this embodiment, by employing a symmetrical fixed seat 5 on the base 1 and connecting it across the guide shaft 6, combined with the precise fit of the sliding member 210 on the guide shaft 6 and the driving arrangement of the drive rod 220 parallel to the guide shaft 6, the technical problems of motion trajectory deviation and jamming caused by excessive cantilever or poor guidance during the movement of the sealing component 2 in the prior art, as well as premature damage to the drive mechanism due to bearing additional radial load, are effectively solved. This enables the sealing component 2 to maintain high-precision linear coaxial movement under high load, significantly reduces operating friction resistance and drive energy consumption, and greatly extends the service life of the core drive components.

[0087] Figure 3 This is a schematic structural diagram of the attitude adjustment mechanism 7 according to an embodiment of the present invention. Please refer to... Figures 1 to 4 In some embodiments, to reduce the effect of eccentricity, the end face of the inner floating sealing disk 320 extending to the outside of the outer support seat 310 is constructed as a convex arc-shaped contact surface 322. The outer diameter of the convex arc-shaped contact surface 322 is larger than the inner diameter of the valve port of the valve under test, and it is configured such that when it abuts against the valve port of the valve under test, the normal force at the contact point points to the axis of the inner floating sealing disk 320. The valve airtightness testing device also includes an attitude adjustment mechanism 7 disposed on the base 1. The attitude adjustment mechanism 7 includes a multi-axis adjustment assembly 710, a mounting plate 720 disposed on the output end 711 of the multi-axis adjustment assembly 710, a pressure sensor array 730 disposed on the convex arc-shaped contact surface 322 of the inner floating sealing disk 320, and a control unit. The multi-axis adjustment assembly 710 includes an output end 711, the mounting plate 720 is used to support the valve under test, and the pressure sensor array 730 includes a pressure sensor 731. The multi-axis adjustment component 710 is configured to carry the valve under test and drive the valve under test to perform multi-degree-of-freedom displacement and deflection in space. The control unit is connected to the pressure sensor array 730 and the multi-axis adjustment component 710 respectively, and is configured to control the output end 711 of the multi-axis adjustment component 710 to move according to the pressure distribution difference fed back by the pressure sensor array 730, so as to adjust the posture of the valve under test until the central axis of the valve under test coincides with the central axis of the inner floating sealing disks 320 on both sides.

[0088] In the aforementioned embodiments, although the differential sealing unit 3 successfully eliminated the deformation interference caused by the external mechanical clamping force on the valve body through the design of the inner floating sealing disc 320, this floating and unconstrained structural feature also introduces a new technical challenge. Specifically, due to the lack of mandatory mechanical locking and positioning between the inner floating sealing disc 320 and the valve under test, when the valve under test (especially large-diameter heavy valves) has an initial alignment deviation between its central axis and the central axis of the inner floating sealing discs 320 on both sides due to hoisting positioning errors or uneven weight distribution, uneven eccentric force is easily generated at the contact interface at the moment the sealing disc extends and abuts the valve port. In the absence of external constraints, this eccentric force will be converted into an uncontrollable overturning torque, causing valve body instability, uneven sealing surface contact, and in severe cases, even valve body overturning accidents. To solve this attitude stability problem induced by the floating sealing characteristics under non-ideal working conditions, this embodiment further proposes an attitude adaptive scheme based on active sensing and closed-loop adjustment.

[0089] In this embodiment, in order to further improve the adaptive capability of the detection device to the positional deviation of the valve under test, the sealing and support system has been significantly improved with intelligent technology.

[0090] The contact surface of the inner floating seal disc 320 extending to the outer bearing seat 310 is constructed as a special convex arc-shaped contact surface 322. This contact surface is typically machined into a high-precision spherical or near-spherical surface, with its geometric center located on the central axis of the inner floating seal disc 320. In terms of dimensional design, the outer contour diameter of this convex arc-shaped contact surface 322 is designed to be strictly larger than the inner diameter of the valve port under test, ensuring that during contact, the contact area is always located on the circumference of the valve port chamfer or end face, and will not slip into the valve interior.

[0091] To accommodate this unique contact structure, a high-precision attitude adjustment mechanism 7 is integrated on the base 1. This mechanism mainly consists of four parts: a multi-axis adjustment component 710, a mounting plate 720, a pressure sensor array 730, and a control unit.

[0092] The multi-axis adjustment assembly 710 is the core actuator for the entire attitude adjustment process, typically employing a high-rigidity parallel mechanism (such as a six-DOF Stuart platform) or a series-superimposed displacement stage. It is securely mounted on the base 1, and its output end 711 has the capability for linear movement (along three orthogonal axes) and rotational deflection (around three orthogonal axes) in three-dimensional space. A mounting plate 720 is disposed on the output end 711 of the multi-axis adjustment assembly 710, serving as the direct interface for supporting the valve under test. It may be equipped with V-blocks or clamps (not shown) to secure the valve.

[0093] The pressure sensing array 730 is directly integrated onto the convex arc-shaped contact surface 322 of the inner floating sealing disc 320. The sensing array consists of multiple independent pressure sensors 731, which are discretized along the circumference of the convex arc surface (e.g., uniformly distributed in a cross or ring shape). The sensors are embedded, with their sensing surfaces flush with or slightly concave to the convex arc surface, to sense contact pressure without compromising the integrity of the sealing surface.

[0094] The control unit (such as an industrial computer or PLC) is connected to the pressure sensor array 730 and the multi-axis adjustment assembly 710 via signal lines to form a closed-loop control system.

[0095] When the test begins, the internal floating sealing disc 320 approaches the valve under test under low pressure. Due to the geometric characteristics of the convex arc-shaped contact surface 322, regardless of the angle of inclination of the valve relative to the axis of the sealing disc, as long as the two make contact, the normal force line at the contact point (i.e., the force perpendicular to the contact tangent) will naturally point towards the center of the convex arc surface (i.e., the central axis of the sealing disc). This geometric characteristic eliminates the uncontrollable overturning torque caused by the eccentricity of the contact point, providing a stable mechanical basis for subsequent active adjustment.

[0096] At the moment of contact, if the central axis of the valve under test does not coincide with the central axis of the sealing disc (there is eccentricity or tilt), the force on each point on the convex arc-shaped contact surface 322 will be uneven. For example, if the valve tilts to the left, the pressure sensor 731 on the left side of the sealing disc will detect the pressure signal first, while the reading of the sensor on the right side may be zero or small.

[0097] The pressure sensor array 730 feeds back this uneven pressure distribution data to the control unit in real time. The control unit runs a differential algorithm to calculate the pressure distribution difference of the current force and converts it into a spatial pose deviation vector.

[0098] Based on the calculation results, the control unit sends motion commands to the multi-axis adjustment assembly 710. The multi-axis adjustment assembly 710 drives the mounting plate 720 and the valve under test to perform corresponding micro-displacement or rotational compensation within the space (e.g., moving or rotating in the opposite direction to the side with greater force) to eliminate the pressure difference. This process is a dynamic closed-loop process until the readings of each sensor in the sensor array tend to be consistent or the difference is within the preset balance threshold range. At this time, it indicates that the circumference of the valve port of the valve under test has been uniformly attached to the convex arc-shaped contact surface 322, achieving high alignment between the central axis of the valve under test and the central axes of the inner floating sealing discs 320 on both sides.

[0099] The technical solution in this embodiment is particularly suitable for the airtightness testing of large-diameter, heavy-duty valves. In such scenarios, the valves are not only extremely heavy, but also prone to initial misalignment due to hoisting errors. This system requires a stable power supply to drive the multi-axis adjustment assembly 710 in the installation environment, and also requires the test area to be free from strong electromagnetic interference to ensure the transmission accuracy of weak sensor signals. Furthermore, the surface quality of the valve port is critical; severe nicks must be avoided to prevent damage to the sensor.

[0100] In this embodiment, the control unit has a pre-installed attitude calculation algorithm. Taking the pressure sensor array 730, which includes four pressure sensors 731 arranged in a cross shape, as an example, these are the upper sensor (P... up ), lower sensor (P) down ), left side sensor (P) left ) and the right-side sensor (P right ).

[0101] When the inner floating seal disc 320 contacts the valve port, the control unit executes the following logic loop:

[0102] Data acquisition and differential calculation: The control unit reads the pressure values ​​from the four sensors in real time and calculates the pressure difference in the vertical direction. and horizontal pressure difference .

[0103] Deviation vector determination:

[0104] like ( (The preset balance threshold) indicates that there is an upward or downward tilting posture deviation between the valve and the sealing disc in the vertical direction (i.e., the upper contact is too tight).

[0105] like This indicates that the valve has a leftward or lateral tilting posture deviation in the horizontal direction (i.e., the left side is too tightly contacted).

[0106] Motion command generation and execution: Based on the aforementioned deviation vector, the control unit uses a PID control algorithm to generate a reverse compensation command and sends it to the multi-axis adjustment component 710.

[0107] against When the value is positive, the multi-axis adjustment assembly 710 drives the mounting plate 720 and valve to move downwards or adjust the pitch angle downwards to reduce the upper contact force until... Return to zero or the threshold range.

[0108] against When the value is positive, the multi-axis adjustment assembly 710 drives the mounting plate 720 and valve to move to the right or adjust the yaw angle to the right to reduce the contact force on the left side until... Return to zero or the threshold range.

[0109] When the pressure difference in all directions is less than the preset threshold (i.e.) When the absolute pressure values ​​of all sensors are greater than zero (ensuring full circumference contact), the control unit determines that the attitude alignment is complete and issues a locking command to lock the current position of the multi-axis adjustment component 710, and then starts the high-pressure medium injection process.

[0110] Through the specific logical mapping described above, the physical quantities of mechanical distribution on the convex arc-shaped contact surface 322 are transformed into kinematic control quantities of the multi-axis mechanism, thereby achieving automated and precise alignment.

[0111] In this embodiment, by constructing the end face of the inner floating sealing disc 320 as a convex arc-shaped contact surface 322 and cooperating with the pressure sensor array 730, combined with the multi-axis adjustment component 710 and control unit on the base 1 to form a closed-loop attitude adjustment system, the geometric characteristics of the convex arc surface are used to guide the contact reaction force to the center of the shaft 6 to eliminate the overturning torque. The uneven distribution of contact pressure is sensed in real time by the sensor, and the multi-axis mechanism is driven to actively adjust the valve position until the pressure is balanced. This effectively solves the technical problem in the prior art that heavy valves are prone to uneven force or even overturning during floating seal testing due to hoisting errors or their own weight, leading to seal failure and equipment damage. In this way, the millisecond-level accurate automatic correction of the spatial attitude of the valve under test is achieved, ensuring the high stability and high safety of the test system in the absence of rigid clamping.

[0112] Please see Figure 2 Furthermore, in some embodiments, the pressure sensing array 730 includes at least four pressure sensors 731, which are evenly spaced in a ring along the circumference of the convex arc-shaped contact surface 322; the pressure sensors 731 are configured such that when the inner floating sealing disc 320 abuts against the valve port of the valve under test, the sensing surface of the pressure sensor 731 is in contact with the chamfered edge of the valve port of the valve under test.

[0113] Specifically:

[0114] In this embodiment, a specific layout optimization design was carried out for the pressure sensing array 730 used to sense the contact state. The pressure sensing array 730 is integrated on the convex arc-shaped contact surface 322 at the front end of the inner floating sealing disk 320, and its core components include at least four high-sensitivity pressure sensors 731.

[0115] In terms of spatial distribution, these at least four pressure sensors 731 are not randomly scattered, but strictly follow the principle of geometric symmetry, and are distributed in a ring with equal spacing along the circumference of the convex arc-shaped contact surface 322. For example, when four sensors are used, they are located at four orthogonal points on the upper, lower, left, and right sides of the convex arc-shaped contact surface 322, and adjacent sensors maintain a right-angle interval; if the number of sensors is increased, the interval angle is decreased sequentially to form a high-density sensing ring.

[0116] The radial depth configuration of the sensor installation location was precisely calculated to match the geometry of the valve port under test. Specifically, the pressure sensor 731 is configured such that when the inner floating sealing disc 320 extends outward and abuts against the valve port under test, the sensor's sensing surface neither contacts the valve's inner wall nor the valve's end flange plane, but rather fits precisely against the chamfered edge of the valve port. This chamfered edge is typically a blunted area or guide bevel during valve machining, exhibiting relatively stable geometric consistency.

[0117] The sensor itself is typically miniaturized and embedded in the mounting hole of the convex arc-shaped contact surface 322. Its sensing surface is designed to be continuous with or slightly recessed from the contour of the convex arc-shaped surface to prevent scratches in non-measuring areas.

[0118] The operating logic of the pressure sensor array 730 in this embodiment is to use multi-point contact feedback to infer the spatial fitting posture.

[0119] When the detection device is activated, the inner floating sealing disc 320 approaches the valve under test, and the convex arc-shaped contact surface 322 first contacts the valve port. Since the pressure sensor 731 is precisely arranged on the annular trajectory corresponding to the chamfered edge of the valve port, once physical contact occurs, the chamfered surface of the valve port will directly press against the corresponding pressure sensor 731.

[0120] If the valve under test and the inner floating sealing disc 320 are in an ideal coaxial state, the chamfered edge of the valve port will press simultaneously and evenly on all the circumferentially distributed sensors, and the pressure signal values ​​output by all sensors will be basically the same.

[0121] If there is angular skew or axial misalignment (e.g., the valve is tilted to one side), the chamfered edge of the valve port will first press against the sensor on one side (e.g., the upper sensor), generating a larger pressure reading, while the sensor on the opposite side (e.g., the lower sensor) has not yet made contact or the contact force is minimal. In this case, this array of equally spaced sensors essentially forms a discrete force circle. By comparing the pressure values ​​at different phase points on the circumference, the tilt direction and degree of the contact interface can be accurately determined.

[0122] The technical solution in this embodiment is applicable to various industrial valves with standard valve port chamfers or transition fillets. For older valves with extremely sharp valve port edges or severe chips, protective gaskets may be required to prevent damage to the sensor. Furthermore, this solution requires the sensor to have a certain overload resistance to withstand the preload before high-pressure testing, and the installation environment must be kept clean to prevent metal shavings or other debris from interfering with the readings between the chamfer and the sensor.

[0123] In one alternative embodiment, the number of pressure sensors 731 can be increased to eight or more to improve resolution for minute angular deviations. Alternatively, an annular piezoresistive film strip can be used instead of individual sensor particles to achieve continuous monitoring of circumferential contact pressure, rather than discrete point monitoring. For valves of different diameters, multiple pre-set sensor mounting holes of different diameters can be provided on the inner floating seal disc 320, or the sensor can be designed as a radially adjustable slider structure to accommodate the chamfer positions of valves of different sizes.

[0124] In this embodiment, by employing a technique of circumferentially distributing at least four pressure sensors 731 along the convex arc-shaped contact surface 322 at equal intervals and precisely configuring their installation positions to fit against the chamfered edge of the valve port to be tested, the chamfered edge is used as a stable contact mechanical reference surface, avoiding interference from the valve end face roughness on the sensors. Furthermore, the circumferentially symmetrically distributed sensor array transforms complex spatial attitude deviations into intuitive differential pressure signals, effectively solving the technical problems in the prior art where attitude perception blind spots are caused by uncertain contact positions and sensors are easily damaged by the sharp edges of the valve port. This achieves highly sensitive omnidirectional capture of the valve docking attitude, providing accurate and reliable data support for subsequent active correction.

[0125] The pressure sensor 731 is a thin-film pressure sensor or a miniature piezoelectric sensor, and is embedded in the surface of the inner floating sealing disk 320. The sensing surface of the pressure sensor 731 is not higher than the contour surface of the convex arc-shaped contact surface 322. The multi-axis adjustment assembly 710 is a six-degree-of-freedom parallel adjustment platform; the mounting plate 720 is provided with a V-shaped adaptive seat or bolt fastening interface for positioning the valve under test. The control unit is configured to control the output end 711 of the multi-axis adjustment assembly 710 to move the valve on the mounting plate 720 when the difference in readings of the sensors in the pressure sensor array 730 at relatively symmetrical positions exceeds a preset threshold, until the central axis of the valve under test is collinear with the central axes of the inner floating sealing disks 320 on both sides.

[0126] Specifically:

[0127] In this embodiment, specific selection and structural optimization were carried out for the core hardware of the attitude perception and execution system.

[0128] The pressure sensor 731 used for sensing contact states is specifically defined as a thin-film pressure sensor 731 or a miniature piezoelectric sensor. The thin-film pressure sensor 731 is typically composed of a flexible substrate and a pressure-sensitive material printed on it, with an extremely thin thickness and excellent flexibility, and can be well attached to curved surfaces; the miniature piezoelectric sensor utilizes the piezoelectric effect of piezoelectric crystals, which responds extremely quickly to changes in dynamic force and is small in size, making it suitable for high-precision point measurements.

[0129] In terms of installation, the pressure sensor 731 is not simply pasted onto a surface, but rather embedded in the convex arc-shaped contact surface 322 of the inner floating sealing disk 320. Specifically, a precision groove or mounting hole matching the sensor's shape is machined on the metal substrate of the inner floating sealing disk 320 at a preset position corresponding to the sensor. The sensor is placed into the groove and fixed with a high-pressure resistant adhesive or encapsulating resin.

[0130] The key structural feature is that, after installation, the sensing surface of the pressure sensor 731 (i.e., the surface that directly contacts the force) is strictly controlled in height to be no higher than the contour surface of the convex arc-shaped contact surface 322. This means that the sensing surface of the sensor is either perfectly flush with the surrounding metal convex arc surface or has a slight inward settlement relative to the metal surface. This design aims to prevent the shear forces generated during the initial sliding or adjustment of the valve port from directly peeling off or scratching the sensor.

[0131] As the actuator for attitude adjustment, the multi-axis adjustment assembly 710 is specifically implemented as a six-degree-of-freedom parallel adjustment platform. This platform mainly consists of a lower fixed base 5, an upper motion platform, and six sets of independently extendable servo electric or hydraulic cylinders connecting the upper and lower parts. These six sets of telescopic cylinders are connected to the upper and lower platforms via universal hinges. By changing the length combination of the six legs, the upper motion platform can be driven to move along three orthogonal axes and rotate around three orthogonal axes in space, exhibiting extremely high stiffness-to-weight ratio and position control accuracy.

[0132] Regarding the connection interface between the mounting plate 720 and the valve under test, two compatible modes are designed: a V-type self-adaptive seat and a bolt-fastening interface. The V-type self-adaptive seat consists of two inclined surfaces arranged at an angle, utilizing the principle of gravity self-centering, and is specifically designed to support valves with a cylindrical valve body, automatically correcting the valve's rolling deviation; the bolt-fastening interface consists of pre-fabricated T-slots or arrayed threaded holes on the mounting plate 720, used to directly fix valves with irregular shapes such as feet or flanges via pressure plates or bolts.

[0133] The core of this system lies in closed-loop position control based on differential feedback.

[0134] During the testing process, when the inner floating sealing disc 320 approaches the valve under test, the embedded pressure sensor 731 begins to sense the contact pressure. Since the sensor's sensing surface is not higher than the contour surface, the sensor will only be subjected to positive compressive force when the valve port chamfer is indeed pressed against the sealing disc surface, thereby outputting an effective electrical signal and avoiding friction interference signals.

[0135] The control unit continuously collects data from the pressure sensor array 730 and executes symmetrical comparison logic: that is, it calculates in real time the pressure reading difference between a pair of sensors that are symmetrical in spatial position (e.g., the top and bottom, or the left and right).

[0136] If the absolute value of this difference exceeds the system's preset balance threshold, it indicates that the valve is eccentric or tilted. For example, if the reading of the upper sensor is significantly greater than that of the lower sensor, it indicates that the valve is tilted or positioned too high. In this case, the control unit calculates the required spatial compensation vector based on the inverse kinematics algorithm of the six-degree-of-freedom parallel mechanism and converts it into drive commands for the six telescopic cylinders.

[0137] The six-degree-of-freedom parallel control platform, acting according to commands, precisely drives the mounting plate 720 and the valve under test to perform minute translational or rotational corrections. This is a dynamic iterative process: detecting the difference, driving adjustment, and detecting again, until the sensor reading difference at the relatively symmetrical position falls back within the preset threshold. At this point, the system determines that the geometric center axis of the valve under test has achieved precise collinearity in space with the center axes of the two inner floating sealing discs 320.

[0138] This solution is suitable for high-end valve testing scenarios requiring extremely high positioning accuracy. Thin-film or piezoelectric sensors require a stable operating environment temperature to minimize the impact of temperature drift, and the sealing disc surface must be kept clean to prevent metal shavings from embedding in the groove and damaging the sensor. The six-degree-of-freedom parallel adjustment platform requires stable industrial power supply support, and its load-bearing capacity must exceed the weight of the valve under test. V-type seats are suitable for pipe-type valves, while bolted interfaces are suitable for flanged or non-standard valves, demonstrating strong versatility.

[0139] In alternative embodiments, for ultra-heavy-duty valves, the six-DOF platform can be hydraulically driven to provide greater lifting force. For small, precision valves, the sensor can be replaced with an array of tactile sensing films to obtain a continuous pressure distribution map.

[0140] In this embodiment, by embedding a thin-film or piezoelectric pressure sensor 731 with the sensing surface not exceeding the contour surface, and combining it with a six-degree-of-freedom parallel adjustment platform and a V-type adaptive seat or bolt interface as the actuator, along with a closed-loop control strategy based on comparing the difference in symmetrical sensor readings with a preset threshold, the technical problems in the prior art—such as the sensor being easily damaged by surface friction and shear, the inability to correct complex postures due to insufficient degrees of freedom of a single adjustment mechanism, and the reliance on human experience for positioning accuracy due to the lack of quantitative alignment standards—are effectively solved. This achieves precise spatial posture alignment of the valve under test in all directions, with high rigidity and automation, while protecting the precision sensing element, significantly improving the automation level and data reliability of the airtightness testing process.

[0141] Figure 5 This is a flowchart illustrating a control method for a valve body airtightness testing device according to an embodiment of the present invention. For better implementation of valve airtightness testing by the valve airtightness testing device in this application, please refer to... Figure 5 A control method for the aforementioned valve airtightness testing device is proposed, comprising the following steps:

[0142] Step S100: Place the valve to be tested on the mounting plate 720 at the output end 711 of the multi-axis adjustment assembly 710, and drive the two sealing assemblies 2 to move toward the valve to be tested until the convex arc-shaped contact surfaces 322 of the two inner floating sealing discs 320 are in contact with the valve port of the valve to be tested.

[0143] Step S200: Based on the data from the pressure sensor array 730 on the inner floating sealing disk 320, determine the force eccentricity vector, and control the output end 711 of the multi-axis adjustment component 710 to move according to the force eccentricity vector, so as to drive the valve under test on the mounting plate 720 to adjust its spatial posture until the values ​​of each pressure sensor 731 are within the balance range, thereby achieving the collinearity of the central axis of the valve under test and the central axis of the inner floating sealing disk 320;

[0144] Step S300: Lock the position of the output end 711 on the multi-axis adjustment assembly 710, and inject high-pressure test medium into the first air passage 312 of the outer bearing seat 310; use the area difference between the first effective pressure-bearing area and the second effective pressure-bearing area to generate a self-sealing force that increases with pressure, so as to complete the high-pressure airtightness test of the valve.

[0145] Step S400: After the test is completed, the high-pressure medium is released, the inner floating sealing disc 320 retracts under the action of the reset force, the sealing component 2 returns to its original position, and is removed from the valve.

[0146] in:

[0147] Step S100 is the valve loading and pre-positioning contact stage.

[0148] In the initial stage of the airtightness testing process, the valve to be tested is first loaded and roughly positioned. Operators or automated hoisting equipment lift the valve above the attitude adjustment mechanism 7. At this point, the control unit first controls the multi-axis adjustment component 710 to return to its initial zero-point state, ensuring it has maximum travel margin during subsequent adjustments.

[0149] Depending on the specific structure of the valve under test, a suitable fixing method is selected: if the valve body is cylindrical or irregularly shaped, it is naturally centered by gravity using the V-shaped self-adaptive seat on the mounting plate 720; if the valve body has a standard base flange 1, the valve is initially locked onto the mounting plate 720 by bolt fastening the interface. At this time, there may be a certain spatial deviation between the valve's central axis and the theoretical central axis of the testing device, which will be corrected in subsequent steps.

[0150] After the valve under test is placed securely, the system enters the feeding process. The control unit sends a drive command to the sealing components 2 on both sides of the base 1. The drive rods 220 on both sides (such as hydraulic cylinders or servo push rods) move synchronously or independently, driving the sliding member 210 and the connected external bearing seat 310 to make axial feeding motion towards the valve under test along the guide shaft 6.

[0151] The moving process is typically divided into two sub-stages: rapid approach and slow contact. In the rapid approach stage, the sealing component 2 quickly shortens the distance to the valve to improve detection efficiency. When the inner floating sealing disc 320 approaches the valve port at a preset distance, the system automatically switches to the slow contact mode. In slow mode, the outer support seat 310 drives the inner floating sealing disc 320 to advance smoothly until the convex arc-shaped contact surface 322 extending from the front end of the inner floating sealing disc 320 makes physical contact with the chamfered edges of the valve ports on both sides of the valve under test.

[0152] At the moment of contact, the pressure sensing array 730 located on the convex arc-shaped contact surface 322 acts as a "contact sensing switch." Once the sensor detects a weak contact pressure signal (indicating contact has occurred), or a sudden change in the current / hydraulic load of the drive mechanism (indicating resistance), the control unit immediately stops the feeding action of the drive rod 220. At this time, the inner floating sealing disc 320 and the valve port maintain only a low-pressure virtual contact or micro-contact state. This contact force is sufficient to establish a physical connection, but is far less than the destructive force that could cause deformation of the valve body or damage to the sensor, thus completing the physical docking preparation before detection.

[0153] Step S200 is to calculate the force eccentricity vector and correct the closed-loop attitude.

[0154] Step S200 is the core step in achieving automatic stress-free alignment of the valve's spatial posture, and its execution process specifically includes the following steps:

[0155] Step S210 describes the method for determining the force eccentricity vector. When determining the force eccentricity vector, the control unit considers the pressure sensor array 730 on the inner floating sealing disk 320 as a set of discrete sampling points in a polar coordinate system or a Cartesian coordinate system. This step includes the following sub-steps:

[0156] Step S211: Method for determining the force eccentricity vector. When determining the force eccentricity vector, the control unit regards the pressure sensing array 730 on the inner floating sealing disk 320 as a set of discrete sampling points in a polar coordinate system or a Cartesian coordinate system.

[0157] Data Mapping and Vector Synthesis: Assume the pressure sensor array 730 consists of N pressure sensors 731 uniformly distributed circumferentially along the convex arc-shaped contact surface 322 (e.g., in four directions: up, down, left, and right). The control unit first acquires the real-time pressure values ​​of each sensor, defines the installation orientation of each sensor as a direction vector, and defines the detected pressure value as the modulus. The control unit uses a vector synthesis method to calculate the current contact center deviation. Specifically, the pressure vectors of all sensors are superimposed, including:

[0158] The vertical component is calculated by subtracting the reading of the lower sensor from the reading of the upper sensor to obtain the vertical eccentricity component. A positive result indicates that the center of force is shifted upwards; a negative result indicates that the center of force is shifted downwards.

[0159] The horizontal component is calculated by determining the pressure difference between the symmetrical sensors in the horizontal direction. For example, the horizontal eccentricity component is obtained by subtracting the reading of the right sensor from the reading of the left sensor.

[0160] By combining the vertical and horizontal eccentricity components, a two-dimensional force eccentricity vector with a clear direction and magnitude is obtained. The direction of this vector indicates the position where the valve chamfer and the sealing disc are in the closest contact, i.e., the position where the valve posture tilts or shifts; the magnitude of this vector reflects the severity of the deviation.

[0161] Step S212: Since the device includes two inner floating sealing discs 320 on the left and right sides, the control unit will simultaneously calculate the eccentricity vector of the left sealing disc ( ) and the eccentric vector of the right sealing disc ( ).

[0162] like and If the directions are the same and the magnitudes are similar, the control unit determines it as an overall translational deviation (e.g., the valve is too high or too far to the left).

[0163] like and If the directions are opposite (for example, the left dial shows greater force on the upper part, while the right dial shows greater force on the lower part), the control unit determines it as an angular rotation deviation (for example, the valve is tilted at a pitch or yaw angle).

[0164] Step S220 is a motion control strategy based on the force eccentricity vector. The control unit, based on the calculated force eccentricity vector and the fusion result of the two-sided data, calculates the required compensation motion for each axis (X, Y, Z, and rotation axis) of the multi-axis adjustment component 710 using an inverse kinematics algorithm. Specifically, this includes the following steps:

[0165] Step S221: The core strategy of the control system is to move towards the side with less force or away from the side with greater force. When an overall translational deviation is determined (e.g., both sides show excessive force on the upper part), the control unit drives the lifting mechanism of the multi-axis adjustment component 710 to move downward, reducing the valve height until the upper and lower pressures are balanced. When an angular rotational deviation is determined (e.g., the upper part of the left plate has greater force, and the lower part of the right plate has greater force, i.e., the valve is in a "raised" posture), the control unit drives the multi-axis adjustment component 710 to perform pitch adjustment (the front end lowers, and the rear end rises) to eliminate the angular error.

[0166] Step S222: Considering the enormous inertia of the heavy valve and the nonlinear friction of the contact surface, the control unit does not perform a one-time full compensation, but instead adopts incremental step control. The details are as follows:

[0167] The control unit generates a tiny displacement step (e.g., 0.05 mm or 0.1 degrees) based on the magnitude of the force eccentricity vector.

[0168] The multi-axis adjustment assembly 710 is driven to perform this small step.

[0169] After execution, the sensor data is read again to recalculate the new force eccentricity vector.

[0170] Repeat the above cycle of detection, calculation, and movement until the deviation vector is reduced to within the allowable range.

[0171] The balance range in step S200 does not mean that the values ​​of all sensors are absolutely equal, but rather that the contact state meets the engineering critical condition of full circumference fit without harmful off-center loading. Its detailed definition and determination steps are as follows:

[0172] Full-circumference contact is a necessary condition, and the primary condition for the balance range is that the readings of all pressure sensors 731 involved in the detection must be greater than the preset minimum contact threshold (a non-zero positive value). This ensures that the chamfered circumference of the valve port has achieved 360-degree gapless physical contact with the convex arc-shaped contact surface 322, and there is no situation of "one side suspended".

[0173] Relative dispersion determination refers to the control unit calculating the dispersion of pressure values ​​from each sensor while ensuring full-circumference contact. Specifically, it calculates the difference between the maximum and minimum pressure values, divides it by the average pressure value of all sensors, and obtains the pressure non-uniformity coefficient. When this pressure non-uniformity coefficient is less than a preset percentage (e.g., 5% or 10%), or when the absolute value of the pressure difference between sensors in relatively symmetrical positions is less than a preset force constant (e.g., 10N), the system determines that the value is within the equilibrium range. Furthermore, to prevent misjudgments caused by dynamic oscillations during the adjustment process, the system requires that the above equilibrium state be maintained continuously for a certain time window (e.g., three consecutive sampling cycles or one second) before the attitude adjustment can be confirmed as complete, and the system proceeds to the locking and pressurization step S300.

[0174] Step S300 is the mechanical locking and differential medium self-locking loading stage.

[0175] Once the spatial orientation of the valve under test is precisely corrected and the inner floating sealing disc 320 achieves ideal coaxial fit with the valve port, the critical self-locking seal and high-pressure test phase begins.

[0176] First, a mechanical locking procedure is executed. The control unit sends a position holding command to the multi-axis adjustment assembly 710. At this time, the multi-axis adjustment assembly 710 (e.g., a servo drive unit of a six-DOF parallel platform) enters a high-rigidity servo locking state or activates a mechanical braking device, absolutely fixing the positions of the output end 711 and the mounting plate 720. This step aims to construct the valve under test as a stable, stationary rigid body in space, preventing unnecessary displacement oscillations caused by airflow impact or force changes during subsequent pressurization, and ensuring the stability of the test benchmark.

[0177] Subsequently, the medium injection and pressure establishment process is initiated. The control unit opens the supply valve of the external high-pressure gas source, and the high-pressure test medium (such as nitrogen or helium) enters the first gas passage 312 opened on the outer support seat 310 through the pipeline connection. The medium first rapidly fills the pressure compensation cavity 4 formed between the outer support seat 310 and the inner floating sealing disc 320.

[0178] During this process, the unique "fluid connectivity and differential force" mechanism of the differential sealing unit 3 begins to play a crucial role. Because the inner floating sealing disc 320 has a through-passage second air passage 321 at its axial center, the high-pressure medium filling the pressure compensation chamber 4 will simultaneously pass through the second air passage 321 and directly enter the internal cavity of the valve under test. This means that throughout the entire pressurization process, the pressure inside the pressure compensation chamber 4 and the pressure inside the valve under test remain in a real-time isobaric communication state.

[0179] Based on Pascal's principle, the system utilizes the difference in effective pressure-bearing areas on both sides of the inner floating sealing disc 320 to generate sealing force. Specifically, the first effective pressure-bearing area (i.e., the driving surface) of the inner floating sealing disc 320 located inside the pressure compensation chamber 4 is designed to be significantly larger than the second effective pressure-bearing area (i.e., the reverse thrust surface) extending to the outside of the outer bearing seat 310 and actually contacting the valve port of the valve under test. Under the same system pressure, the outward thrust acting on the first effective pressure-bearing area is significantly greater than the inward reverse thrust acting on the second effective pressure-bearing area. The difference between these two opposing forces forms a net sealing thrust pointing towards the valve under test.

[0180] As the pressure of the injected medium increases, the net sealing thrust automatically increases linearly. This mechanism creates a positive feedback self-locking effect: the higher the test pressure, the greater the force with which the internal floating sealing disc 320 presses against the valve port, thus ensuring that the sealing interface remains leak-proof even under extremely high pressure, and never generating excessive clamping force exceeding the sealing requirements. When the pressure reaches the preset test standard value, the system shuts off the air supply and enters the pressure holding monitoring stage. The final evaluation of the valve's pressure resistance and sealing performance is completed by observing the pressure decay or using external leak detection instruments.

[0181] This step effectively solves the technical problem in the prior art that the need to apply a constant and huge mechanical clamping force in advance leads to excessive clamping force causing valve body deformation during low-pressure testing, while insufficient clamping force may cause valve body to burst during high-pressure testing. This is because the pressure compensation chamber 4 is connected to the valve body through the through air channel after the position is locked, and the loading is based on the principle that the first effective pressure-bearing area on both sides of the inner floating sealing disc 320 is greater than the second effective pressure-bearing area. This achieves a breathing adaptive seal with automatic dynamic adjustment of sealing clamping force according to the test pressure, which not only ensures absolute safety and self-locking under extreme pressure, but also eliminates additional stress damage to the valve body to the greatest extent.

[0182] Step S400 is the stage of system depressurization, reset and workpiece removal.

[0183] After completing the pressure holding test and acquiring all test data, the system enters the final depressurization and disengagement process. The operational logic of this stage strictly follows the safety principle of depressurizing first and then separating to prevent mechanical rebound or damage to the sealing surface caused by residual high-pressure gas.

[0184] First, the control unit sends an exhaust command to the air circuit system, opening the pressure relief valve located on the air intake pipe of the outer support seat 310. At this time, the high-pressure medium in the pressure compensation chamber 4 begins to release outward, and the pressure inside the chamber drops rapidly. Because the inner floating seal disc 320 has a through-hole second air passage 321, the high-pressure medium inside the valve under test will flow back to the pressure compensation chamber 4 through this air passage and be released together. This reverse flow mechanism ensures that the pressure inside the valve body and the pressure compensation chamber 4 decrease synchronously during the pressure relief process, avoiding the situation where the seal disc is attracted to the valve port and cannot detach due to sudden pressure difference changes.

[0185] As the system pressure decreases, the net sealing thrust acting on the difference between the first and second effective pressure-bearing areas of the inner floating seal disc 320 gradually diminishes until it disappears. At this time, the inner floating seal disc 320 retracts under the action of the reset force. This reset force is usually provided by an elastic reset element 340 (such as a built-in reset spring) located between the inner floating seal disc 320 and the outer support seat 310. When the air pressure thrust is less than the elastic restoring force of the spring, the inner floating seal disc 320 slides inward relative to the outer support seat 310, and its front end convex arc-shaped contact surface 322 smoothly disengages from the valve port chamfer of the valve under test, eliminating the physical contact stress between the two.

[0186] After confirming that the system pressure has been completely released and the sealing disc has initially retracted, the control unit releases the position lock on the multi-axis adjustment assembly 710 and drives the drive rod 220 of the sealing assembly 2 to move in the opposite direction. Driven by the drive rod 220, the outer support seat 310 quickly retracts to its initial position along the guide shaft 6 in a direction away from the valve under test, thereby leaving sufficient safe working space on both sides of the valve under test.

[0187] Finally, the operator or automated robot loosens the fixing mechanism (such as V-shaped seat or bolt) on the mounting plate 720, removes the valve that has completed the test from the multi-axis adjustment assembly 710, and prepares to load the next workpiece to be tested, thus completing the entire testing cycle.

[0188] This step utilizes a through-flow air passage to achieve synchronous reverse pressure relief between the valve body and the compensation chamber, and employs an elastic element to provide a reset force so that the inner floating sealing disc 320 automatically retracts after the pressure is eliminated. Therefore, it effectively solves the safety hazards in existing technologies where residual high pressure causes the sealing disc to become stuck and unable to separate, or where forced mechanical separation under pressure leads to damage to the sealing surface and the ejection of high-pressure gas. This achieves smooth and non-destructive separation and rapid system reset after the test, significantly improving the safety and cycle efficiency of the testing operation.

[0189] The above description is merely illustrative of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not depart from the content of this specification or exceed the scope defined by the claims, all of which should fall within the protection scope of this invention.

Claims

1. A valve airtightness testing device, characterized in that, include: Base; Two sealing components are disposed on the base and arranged opposite to each other, and the two sealing components are configured to move in a controlled manner toward the valve ports on both sides of the valve to be tested, respectively. A differential sealing unit disposed on the sealing assembly, the differential sealing unit comprising: An external support seat is connected to the sealing assembly. The external support seat has a receiving cavity inside, and a first air passage communicating with the receiving cavity is opened on the external support seat. An inner floating sealing disc is slidably disposed within the outer bearing seat. The inner floating sealing disc is sealed and fitted within the receiving cavity. The side of the inner floating sealing disc near the sealing assembly and the inner wall of the receiving cavity form a pressure compensation cavity, which is connected to an external high-pressure air source through the first air passage. The inner floating sealing disc is provided with a second air passage penetrating its own axial direction. The inner floating sealing disc is at least partially located outside the outer bearing seat. The end face of the inner floating sealing disc extending outside the outer bearing seat is constructed as a convex arc-shaped contact surface. The outer diameter of the convex arc-shaped contact surface is larger than the inner diameter of the valve port to be tested, and it is configured such that when it abuts against the valve port to be tested, the normal force at the contact point points points towards the axis of the inner floating sealing disc. Wherein, the central axes of the two inner floating sealing discs are collinear; and the first effective pressure-bearing area of ​​the inner floating sealing disc located in the pressure compensation chamber is greater than the second effective pressure-bearing area of ​​the end face of the inner floating sealing disc located outside the outer bearing seat for contacting the valve port of the valve under test; the valve airtightness testing device is configured such that when an external high-pressure air source injects high-pressure medium into the pressure compensation chamber through the first air passage and the second air passage, the net thrust generated by the difference between the first effective pressure-bearing area and the second effective pressure-bearing area drives the inner floating sealing disc to extend outward from the outer bearing seat and press against the valve port of the valve under test; An attitude adjustment mechanism is disposed on the base, the attitude adjustment mechanism comprising: Multi-axis adjustment assembly, including output end; A mounting plate disposed at the output end of the multi-axis adjustment assembly is used to support the valve to be tested. A pressure sensing array is disposed on the convex arc-shaped contact surface of the inner floating sealing disk, the pressure sensing array including a pressure sensor; The multi-axis adjustment assembly is configured to support the valve under test and drive the valve under test to perform multi-degree-of-freedom displacement and deflection in space. The control unit is connected to the pressure sensor array and the multi-axis adjustment assembly respectively, and is configured to control the output end of the multi-axis adjustment assembly to move according to the pressure distribution difference fed back by the pressure sensor array, so as to adjust the posture of the valve under test until the central axis of the valve under test coincides with the central axis of the inner floating sealing discs on both sides. The control unit is configured to control the output end of the multi-axis adjustment component to move the valve on the mounting plate when the difference in readings of the sensors in the pressure sensing array at relatively symmetrical positions exceeds a preset threshold, until the central axis of the valve under test is collinear with the central axis of the inner floating sealing discs on both sides.

2. The valve airtightness testing device according to claim 1, characterized in that, The inner wall of the receiving cavity of the outer bearing seat is provided with a sliding groove along its own axial direction. The inner floating sealing disc has a stepped piston-shaped structure. The large-diameter end of the piston-shaped structure is slidably sealed in the sliding groove, and the small-diameter end of the piston-shaped structure extends to the outside of the outer bearing seat. A sealing component is provided at the fitting gap between the inner floating sealing disc and the outer bearing seat.

3. The valve airtightness testing device according to claim 1, characterized in that, The base has two symmetrically arranged fixing seats, and each sealing component is mounted on each fixing seat. A guide shaft is provided between the two fixing seats, and the axial direction of the guide shaft is parallel to the moving direction of the sealing component. The sealing component includes: A sliding member is slidably disposed on the guide shaft, and the sliding member is connected to the outer bearing seat; A controlled-movement drive rod, the direction of movement of the drive rod being parallel to the axial direction of the guide shaft, the drive rod being connected to the outer support seat to drive the outer support seat to move along the guide shaft.

4. The valve airtightness testing device according to claim 1, characterized in that, The pressure sensing array includes at least four pressure sensors, which are evenly spaced in a ring along the circumference of the convex arc-shaped contact surface. The pressure sensors are installed in such a way that when the inner floating sealing disc abuts against the valve port of the valve under test, the sensing surface of the pressure sensor is in contact with the chamfered edge of the valve port of the valve under test.

5. The valve airtightness testing device according to claim 4, characterized in that, The pressure sensor is a thin-film pressure sensor or a miniature piezoelectric sensor, and is embedded in the surface of the inner floating sealing disc. The sensing surface of the pressure sensor is not higher than the contour surface of the convex arc-shaped contact surface.

6. The valve airtightness testing device according to claim 5, characterized in that, The multi-axis adjustment assembly is a six-degree-of-freedom parallel adjustment platform; the mounting plate is equipped with a V-type adaptive seat or bolt fastening interface for positioning the valve under test.

7. A control method for the valve airtightness detection device according to any one of claims 4 to 6, characterized in that, Includes the following steps: Place the valve to be tested on the mounting plate at the output end of the multi-axis adjustment assembly, and drive the two sealing assemblies to move toward the valve to be tested until the convex arc-shaped contact surfaces of the two inner floating sealing discs fit against the valve port of the valve to be tested. Based on the data from the pressure sensor array on the inner floating sealing disc, the force eccentricity vector is determined, and the output end of the multi-axis adjustment component is controlled to move according to the force eccentricity vector, so as to drive the valve under test on the mounting plate to adjust its spatial posture until the values ​​of each pressure sensor are within the balance range, thereby achieving the collinearity of the central axis of the valve under test and the central axis of the inner floating sealing disc. Lock the position of the output end on the multi-axis adjustment assembly, and inject high-pressure test medium into the first air passage of the outer bearing seat; use the area difference between the first effective pressure-bearing area and the second effective pressure-bearing area to generate a self-sealing force that increases with pressure, so as to complete the high-pressure airtightness test of the valve. After the test is completed, the high-pressure medium is released, the inner floating sealing disc retracts under the action of the reset force, the sealing assembly returns to its original position, and is removed from the valve.

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