A check valve air tightness detection device and method

Abstract

This application provides a method for detecting the airtightness of a check valve. A mechanical pump simultaneously connects and seals both the actuating chamber and the check chamber, and injects helium into the actuating chamber, causing the pressure in the actuating chamber to rise to P1. The mechanical pump then simultaneously extracts gas from both the actuating and check chambers, resulting in a negative pressure of P2 in the check chamber. A molecular pump then extracts helium from the actuating chamber, resulting in a negative pressure of P3. P2 is compared to PJ. If P2 = PJ, and the helium content in the check chamber slowly decreases to a stable state, the check chamber is determined to be leak-free. Similarly, P3 is compared to PF. If P3 = PF, and the helium content in the actuating chamber continuously decreases to a stable state, the actuating chamber is determined to be leak-free. The aforementioned check valve airtightness detection device and method simulate the dynamic situation during the operation of a one-way valve through the negative pressure suction of a mechanical pump and a molecular pump. In a single test, a helium detector is used to achieve highly sensitive leak detection in both the check chamber and the actuating chamber.

Description

Technical Field

[0001] This application relates to the field of airtightness testing, and more particularly to a device and method for testing the airtightness of a check valve. Background Technology

[0002] As a key component in fluid control systems, the airtightness of the valve body directly affects the system's operational stability and safety. In industrial, medical, automotive, and aerospace fields, valve body sealing performance requirements are high, especially under high or negative pressure environments. Even a small leak can lead to reduced system efficiency, increased energy consumption, or even affect the normal operation of the equipment.

[0003] The airtightness testing of existing check valves typically employs a high-pressure gas testing method, which involves introducing high-pressure gas into both the inlet and outlet of the valve to test its sealing performance. This method requires two independent tests to determine the leakage situation at both ends of the check valve.

[0004] Existing methods for testing the airtightness of one-way valves have several drawbacks: First, the pressure change in the detection chamber needs to be maintained for a period of time after the high-pressure gas is introduced in order to identify whether there is a leak. Furthermore, two separate tests are required to determine the sealing condition at both ends, resulting in a long testing cycle. In addition, the pressure change is not obvious in the case of minor leaks, leading to inaccurate test results. Summary of the Invention

[0005] In view of this, it is necessary to provide a simple and fast-responding device and method for testing the airtightness of check valves to solve the above problems.

[0006] Embodiments of this application provide a method for testing the airtightness of a check valve, comprising the following steps: A check valve is provided, the check valve including a valve body and a check element disposed in the valve body, the valve body having a working chamber communicating with the outside, the check element dividing the working chamber into an actuating chamber and a check chamber, the opening pressure of the check element being P, the standard working negative pressure of the mechanical pump being PJ, the standard working negative pressure of the molecular pump being PF, PF > P > PJ, and the actuating chamber and the check chamber being respectively connected to a helium detector; The mechanical pump simultaneously connects and seals the actuation chamber and the check chamber, and injects helium into the actuation chamber, at which point the gas pressure in the actuation chamber rises to P1; The mechanical pump simultaneously extracts the gas present in the actuation chamber and the check chamber, at which time the negative pressure in the check chamber reaches P2; Helium gas is drawn from the actuation chamber by the molecular pump, at which point the negative pressure in the actuation chamber reaches P3; Compare P2 and PJ. If P2 = PJ, and the helium content in the check chamber slowly decreases to a stable state, it is determined that the check chamber has no leakage. Otherwise, the location of the leakage point is determined based on the change in helium concentration and the comparison result of P2 and PJ. Compare P3 and PF. If P3 = PF and the helium content in the actuation chamber continuously decreases to a stable state, it is determined that there is no leakage in the actuation chamber. Otherwise, the location of the leakage point is determined based on the change in helium concentration and the comparison results of P3 and PF.

[0007] In at least one embodiment of this application, the step "comparing P2 and PJ, if P2 = PJ, and the helium content in the check cavity slowly decreases to a stable state, it is determined that the check cavity has no leakage; otherwise, the location of the leakage point is determined based on the change in helium concentration and the comparison result of P2 and PJ" further includes a determination step: If the comparison result is P2 < PJ, and the helium content slowly decreases until it reaches a stable state, then the sidewall of the check cavity leaks.

[0008] In at least one embodiment of this application, the step "comparing P2 and PJ, if P2 = PJ, and the helium content in the check cavity slowly decreases to a stable state, it is determined that the check cavity has no leakage; otherwise, the location of the leak point is determined based on the change in helium concentration and the comparison result of P2 and PJ" further includes a determination step: If the comparison result is P2 < PJ, and the helium content decreases slowly and then increases, then the check valve on one side of the actuation cavity leaks.

[0009] In at least one embodiment of this application, the step "comparing P3 and PF; if P3 = PF, and the helium content in the actuation chamber continuously decreases to a stable state, it is determined that there is no leakage in the actuation chamber; otherwise, the location of the leakage point is determined based on the helium concentration change and the comparison result of P3 and PF" further includes a determination step: If the comparison result is P3 < PJ, the helium content in the actuation chamber continues to decrease to a stable state, and the helium content in the check chamber remains stable, then the sidewall of the actuation chamber leaks.

[0010] In at least one embodiment of this application, the step "comparing P3 and PF; if P3 = PF, and the helium content in the actuation chamber continuously decreases to a stable state, it is determined that there is no leakage in the actuation chamber; otherwise, the location of the leakage point is determined based on the helium concentration change and the comparison result of P3 and PF" further includes a determination step: If the comparison result is P3 < PF, and the helium content in the actuation chamber continues to decrease to a stable state, then decreases again and remains stable, and the helium content in the check chamber decreases, then the check valve on one side of the check chamber leaks.

[0011] In at least one embodiment of this application, when it is determined that there is no leakage in the check chamber and the actuation chamber, the connection ends of the mechanical pump and the molecular pump with the check valve are moved to the ports of the actuation chamber and the check chamber; Repeat the step "simultaneously extract the gas present in the actuation chamber and the check chamber by the mechanical pump, at which time the negative pressure in the check chamber reaches P2; Helium gas is drawn from the actuation chamber by the molecular pump, at which point the negative pressure inside the actuation chamber reaches P3; then, a determination step is included: Compare P2 and PJ. If the comparison result is P2 < PJ, then it is determined that the check cavity port is leaking. Compare P3 and PF. If the comparison result is P3 < PF, it is determined that the actuation cavity port has leaked.

[0012] In at least one embodiment of this application, when it is determined that there is no leakage in the check chamber and the actuation chamber, a sealing cover is provided to cover the check valve, helium is injected into the sealing cover and a helium detector is connected, and the step "the gas present in the actuation chamber and the check chamber is simultaneously extracted by the mechanical pump, at which time the negative pressure in the check chamber reaches P2; Helium gas is drawn from the actuation chamber by the molecular pump, at which point the negative pressure inside the actuation chamber reaches P3; then, a determination step is included: Observe the helium concentration inside the sealing cover. If the helium concentration decreases, there are micropores on the side wall of the check valve.

[0013] In at least one embodiment of this application, the steps of claim 1 are repeated to prevent accidental errors in detection.

[0014] A check valve airtightness testing device, comprising a check valve airtightness testing method as described in any of the above claims, the testing device further comprising: A check valve includes a valve body and a check element movably connected to the valve body. The check element is disposed in the valve body and divides the valve body into an actuating chamber and a check chamber. The suction assembly includes a mechanical pump and a molecular pump, wherein the mechanical pump is connected to the actuation chamber and the check chamber respectively, and the molecular pump is connected to the actuation chamber; A detection component, connected to the suction tube, is used to detect the helium concentration inside the check valve; The suction assembly further includes a suction tube movably connected to the valve body. The suction tube abuts against the inner walls of the check chamber and the actuation chamber respectively, and is used to detect leakage in different areas of the valve body.

[0015] In at least one embodiment of this application, the suction tube includes a main body and an elastic layer. One end of the elastic layer is disposed on the main body, and the other end is inclined outward. The inner surfaces of the check cavity and the actuation cavity both have a stepped surface. When the suction tube is inserted into the valve body, the elastic layer abuts against the stepped surface. The detection device also includes a sealing cover over the check valve, the sealing cover being connected to the detection component and used to isolate external air.

[0016] The aforementioned check valve airtightness testing device and method utilizes a combination of a mechanical pump and a molecular pump to detect leaks in both the check chamber and the actuating chamber during a single test. The combination of the molecular pump and the mechanical pump simulates the dynamic conditions during the operation of the one-way valve. Detection is performed using negative pressure suction, with helium as the tracer gas. Leveraging the high diffusivity and low background concentration of helium molecules, and in conjunction with a helium detector, highly sensitive leak detection is achieved. This results in faster response times and accurate identification of minute leak points, thus improving detection accuracy. Attached Figure Description

[0017] Figure 1 This is a flowchart of the steps for a check valve airtightness testing method according to the first application of this application.

[0018] Figure 2 for Figure 1 A flowchart illustrating the steps for determining leakage in the check cavity of a check valve airtightness testing method.

[0019] Figure 3 for Figure 1 A flowchart illustrating the steps for determining leakage in the actuating chamber of a check valve airtightness testing method.

[0020] Figure 4 This is a perspective view of a check valve airtightness testing device according to an embodiment of this application.

[0021] Figure 5 for Figure 4 A cross-sectional view of the check valve airtightness testing device.

[0022] Figure 6 for Figure 5 Enlarged view of part A of the check valve airtightness testing device.

[0023] Explanation of main component symbols 100. A check valve airtightness testing device; 10. Check valve; 11. Valve body; 12. Check element; 13. Actuating chamber; 14. Check chamber; 20. Suction assembly; 21. Mechanical pump; 22. Molecular pump; 23. Suction pipe; 231. Main body; 232. Elastic layer; 30. Testing assembly; 40. Sealing cover; 50. Stepped surface. Detailed Implementation

[0024] The embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0025] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or may also have an intervening component. When a component is considered to be "placed" on another component, it can be directly placed on the other component or may also have an intervening component. The terms "top," "bottom," "upper," "lower," "left," "right," "front," "back," and similar expressions used in this article are for illustrative purposes only.

[0026] Embodiments of this application provide a method for testing the airtightness of a check valve, comprising the following steps: A check valve is provided, the check valve including a valve body and a check element disposed in the valve body, the valve body having a working chamber communicating with the outside, the check element dividing the working chamber into an actuating chamber and a check chamber, the opening pressure of the check element being P, the standard working negative pressure of the mechanical pump being PJ, the standard working negative pressure of the molecular pump being PF, PF > P > PJ, and the actuating chamber and the check chamber being respectively connected to a helium detector; The mechanical pump simultaneously connects and seals the actuation chamber and the check chamber, and injects helium into the actuation chamber, at which point the gas pressure in the actuation chamber rises to P1; The mechanical pump simultaneously extracts the gas present in the actuation chamber and the check chamber, at which time the negative pressure in the check chamber reaches P2; Helium gas is drawn from the actuation chamber by the molecular pump, at which point the negative pressure in the stop actuation chamber reaches P3. Compare P2 and PJ. If P2 = PJ, and the helium content in the check chamber slowly decreases to a stable state, it is determined that the check chamber has no leakage. Otherwise, the location of the leakage point is determined based on the change in helium concentration and the comparison result of P2 and PJ. Compare P3 and PF. If P3 = PF and the helium content in the actuation chamber continuously decreases to a stable state, it is determined that there is no leakage in the actuation chamber. Otherwise, the location of the leakage point is determined based on the change in helium concentration and the comparison results of P3 and PF.

[0027] The aforementioned check valve airtightness testing device and method utilizes a combination of a mechanical pump and a molecular pump to detect leaks in both the check chamber and the actuating chamber during a single test. The combination of the molecular pump and the mechanical pump simulates the dynamic conditions during the operation of the one-way valve. Detection is performed using negative pressure suction, with helium as the tracer gas. Leveraging the high diffusivity and low background concentration of helium molecules, and in conjunction with a helium detector, highly sensitive leak detection is achieved. This results in a faster response time and accurate identification of minute leak points, thus improving detection accuracy.

[0028] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] Please see Figures 1-6 This application provides a method for testing the airtightness of a check valve 10, comprising the following steps: A check valve 10 is provided, the check valve 10 includes a valve body 11 and a check element 12 disposed in the valve body 11. The valve body 11 has a working chamber communicating with the outside. The check element 12 divides the working chamber into an actuation chamber 13 and a check chamber 14. The opening pressure of the check element 12 is P. The standard working negative pressure of the mechanical pump 21 is PJ. The standard working negative pressure of the molecular pump 22 is PF, where PF > P > PJ. The actuation chamber 13 is connected to a helium detector. The mechanical pump 21 simultaneously connects and seals the actuation chamber 13 and the check chamber 14, and injects helium into the actuation chamber 13. At this time, the gas pressure in the actuation chamber 13 rises to P1. The mechanical pump 21 simultaneously extracts the gas present in the actuation chamber 13 and the check chamber 14, at which time the negative pressure in the check chamber 14 reaches P2; Helium gas is drawn from the actuation chamber 13 by the molecular pump 22, at which time the negative pressure in the actuation chamber 13 reaches P3; Compare P2 and PJ. If P2 = PJ, and the helium content in the check chamber 14 slowly decreases to a stable state, it is determined that the check chamber 14 has no leakage. Otherwise, the location of the leakage point is determined based on the change in helium concentration and the comparison result of P2 and PJ. Compare P3 and PF. If P3 = PF and the helium content in the actuation chamber 13 continuously decreases to a stable state, it is determined that the actuation chamber 13 has no leakage. Otherwise, the location of the leakage point is determined based on the change in helium concentration and the comparison results of P3 and PF.

[0030] Specifically, the working negative pressure PF of the molecular pump 22 is set higher than the opening pressure P of the check valve 12 to ensure that the check valve 12 will not be accidentally opened during the test, affecting the test results. Both cavities are in a static and sealed state, simulating the state of the check valve 10 during operation. This ensures that the check valve 12 remains closed throughout the entire test, allowing the actuating chamber 13 and the check chamber 14 to be tested independently, improving test accuracy. The mechanical pump 21 connects and seals the actuating chamber 13 and the check chamber 14, and injects helium into the actuating chamber 13, raising the pressure in the actuating chamber 13 to P1, simulating the pressure of the check valve 10 during operation. Helium is then introduced into the actuating chamber 13 as a tracer gas. Helium, due to its small molecular size and strong diffusivity, can quickly penetrate tiny gaps, improving the sensitivity of leak detection.

[0031] Furthermore, the mechanical pump 21 draws gas from both chambers, bringing the check chamber 14 to a negative pressure P2, simulating leakage during normal operation. When P2 = PJ, the standard working negative pressure, it indicates that there is no leakage point in the check chamber 14, and the helium content in the check chamber 14 is partially drawn by the mechanical pump 21. The helium detector shows a curve of decreasing helium levels. When the mechanical pump 21 reaches the working negative pressure, it can no longer draw air from the check chamber 14, and the helium content remains stable.

[0032] Furthermore, the mechanical pump 21 first extracts air from the actuation chamber 13 and the check chamber 14, significantly reducing the air content within the chambers. Through the suction of the mechanical pump 21, large molecular gases in the chambers are preferentially removed. Helium, being a highly adhesive and inert gas, leaves helium as the dominant residual gas. The molecular pump 22, with a pumping speed much higher than the mechanical pump 21, achieves a higher vacuum. The molecular pump 22 further extracts the residual helium, reaching a negative pressure of P3. When P3 = PF (working negative pressure), it indicates that there is no leakage point in the actuation chamber 13, and the helium meter displays a curve showing a decrease in helium levels. When the molecular pump 22 reaches its working negative pressure, it can no longer extract helium from the check chamber 14, and the helium content remains stable.

[0033] In summary, the combined suction design of mechanical pump 21 and molecular pump 22 allows for a single-step test to verify the airtightness of check valve 10. Helium molecules are small and highly diffusive, enabling rapid penetration through minute gaps. Combined with the low background concentration detection capability of the helium analyzer, ppm-level leak identification is achieved. Simulating real-world operating conditions and employing a dual-judgment logic based on pressure and helium concentration, high sensitivity and high precision detection of the airtightness of check valve 10 are achieved.

[0034] In a specific embodiment, the step "Compare P2 with PJ. If P2 = PJ and the helium content in the check valve chamber 14 slowly decreases to a stable state, it is determined that there is no leakage in the check valve chamber 14. Otherwise, based on the change in helium concentration and the comparison result of P2 and PJ, the position of the leakage point is obtained." further includes a determination step: If the comparison result is P2 < PJ and the helium content slowly decreases to maintain a stable state, then there is a leakage in the side wall of the check valve chamber 14.

[0035] Specifically, P2 is the actual negative pressure value reached by the check valve chamber 14 after the mechanical pump 21 extracts the gas in the actuating chamber 13 and the check valve chamber 14; PJ is the standard working negative pressure (expected value) of the mechanical pump 21. If P2 < PJ, it indicates that the negative pressure in the check valve chamber 14 has not reached the theoretical value and there is gas leakage. The actual negative pressure in the check valve chamber 14 is lower than the theoretical working negative pressure of the mechanical pump 21, indicating that external gas enters the check valve chamber 14 through the leakage point, resulting in a pressure rise.

[0036] Furthermore, due to the continuous suction of the mechanical pump 21, the helium concentration in the check valve chamber 14 will gradually decrease. When the working negative pressure reaches the leakage pressure of the leakage point, external air slowly enters the check valve chamber 14 through the leakage point and reaches a dynamic balance with the suction rate of the mechanical pump 21. However, due to the air flow state and the incomplete uniformity of the suction of the mechanical pump 21, the helium concentration may fluctuate at a small frequency. And the concentration value of the helium concentration stable curve at this time is higher than the helium concentration value without leakage in the check valve chamber 14.

[0037] In a specific embodiment, the step "Compare P2 with PJ. If P2 = PJ and the helium content in the check valve chamber 14 slowly decreases to a stable state, it is determined that there is no leakage in the check valve chamber 14. Otherwise, based on the change in helium concentration and the comparison result of P2 and PJ, the position of the leakage point is obtained." further includes a determination step: If the comparison result is P2 < PJ and the helium content first slowly decreases and then increases, then there is a leakage in the check valve member 12 on one side of the check valve chamber 14.

[0038] Specifically, similar to the above determination step, if P2 < PJ, it indicates that the negative pressure in the check valve chamber 14 has not reached the theoretical value and there is gas leakage. The actual negative pressure in the check valve chamber 14 is lower than the theoretical working negative pressure of the mechanical pump 21, indicating that external gas enters the check valve chamber 14 through the leakage point, resulting in a pressure rise. Observe the helium content in the helium detector. The mechanical pump 21 sucks the air in the check valve chamber 14, and the helium content continuously decreases. When the negative pressure reaches the leakage pressure of the leakage point, the air in the actuating chamber 13 leaks into the check valve chamber 14. Since the helium concentration in the actuating chamber 13 is greater than the helium concentration in the check valve chamber 14 and the helium content first decreases and then increases, there is a leakage in the sealing surface of the check valve member 12 on one side of the check valve chamber 14.

[0039] In a specific embodiment, the step "Compare P3 with PF. If P3 = PF and the helium content in the actuating chamber 13 continuously decreases to a stable state, it is determined that there is no leakage in the actuating chamber 13. Otherwise, based on the change in helium concentration and the comparison result between P3 and PF, the position of the leakage point is obtained." further includes a determination step: If the comparison result is P3 < PF, the helium content in the actuating chamber 13 continuously decreases to a stable state, and the helium content in the check valve chamber 14 remains in a stable state, then the side wall of the actuating chamber 13 leaks.

[0040] Specifically, P3 is the actual negative pressure value reached by the check valve chamber 14 after the molecular pump 22 extracts the helium in the actuating chamber 13; PF is the standard operating negative pressure (expected value) of the molecular pump 22. P3 < PJ indicates that the actual negative pressure in the actuating chamber 13 is lower than the theoretical operating negative pressure of the molecular pump 22, indicating that external gas enters the actuating chamber 13 through the leakage point, resulting in a pressure rise. Observe the helium content in the helium detector. The helium concentration in the actuating chamber 13 continuously decreases to a stable state, and the helium concentration in the check valve chamber 14 remains stable, indicating that the gas on the side of the check valve chamber 14 does not flow into the actuating chamber 13, and it is determined that the side wall of the actuating chamber 13 leaks.

[0041] In a specific embodiment, the step "Compare P3 with PF. If P3 = PF and the helium content in the actuating chamber 13 continuously decreases to a stable state, it is determined that there is no leakage in the actuating chamber 13. Otherwise, based on the change in helium concentration and the comparison result between P3 and PF, the position of the leakage point is obtained." further includes a determination step: If the comparison result is P3 < PF, and after the helium content in the actuating chamber 13 continuously decreases to a stable state, it drops again and remains stable, and the helium content in the check valve chamber 14 drops, then the check valve 12 on the side of the check valve chamber 14 leaks.

[0042] Specifically, P3 < PF indicates that the negative pressure in the actuating chamber 13 does not reach the theoretical value and there is gas leakage; the molecular pump 22 sucks the remaining helium in the actuating chamber 13, and the helium content continuously decreases. When the negative pressure reaches the leakage pressure of the leakage point, the air in the actuating chamber 13 leaks into the check valve chamber 14. At this time, the helium content in the actuating chamber 13 rises, and the helium content on the side of the check valve chamber 14 drops. At this time, the sealing surface of the check valve 12 on the side of the actuating chamber 13 leaks.

[0043] In a specific embodiment, when it is determined that the check valve 10 and the pressure relief valve have no leakage, move the connection ends of the mechanical pump 21 and the molecular pump 22 to the ports of the actuating chamber 13 and the check valve chamber 14. Repeat the step "The gas present in the actuation chamber 13 and the check chamber 14 is simultaneously extracted by the mechanical pump 21, at which time the negative pressure in the check chamber 14 reaches P2; Helium gas is drawn from the actuation chamber 13 by the molecular pump 22, at which point the negative pressure inside the actuation chamber 13 reaches P3; then a determination step is included: Compare P2 and PJ. If the comparison result is P2 < PJ, then it is determined that the check cavity 14 port is leaking. Compare P3 and PF. If the comparison result is P3 < PF, then it is determined that the actuation cavity 13 port has a leak.

[0044] Specifically, after determining that there is no leakage, the connection ends of the mechanical pump 21 and the molecular pump 22 are moved from the valve body 11 of the check valve 10 to the ports of the actuation chamber 13 and the check chamber 14, and the airtightness of the ports is directly tested. The pumping steps of the mechanical pump 21 and the molecular pump 22 are repeated to ensure that the test conditions are consistent with those of the valve body 11, so as to avoid misjudgment due to differences in operation.

[0045] Furthermore, the actual negative pressure at the port of check chamber 14 is lower than the theoretical operating negative pressure of mechanical pump 21, indicating that external gas enters check chamber 14 through the port leakage point, causing the pressure to rise. The actual negative pressure at the port of check chamber 14 is also lower than the theoretical operating negative pressure of molecular pump 22, indicating that external gas enters check chamber 14 through the port leakage point, causing the pressure to rise. Since actuation chamber 13 and check chamber 14 have been determined to be leak-free, any abnormal pressure indicates a leak at the corresponding port.

[0046] Furthermore, repeat all the steps of testing the check cavity 14, the actuation cavity 13 and their ports, and compare the results multiple times to prevent accidental mistests.

[0047] In one specific embodiment, when it is determined that there is no leakage between the check valve 10 and the pressure relief valve, a sealing cover 40 is provided to cover the check valve 10, helium is injected into the sealing cover 40, and a helium detector is connected. The step "the gas present in the actuation chamber 13 and the check chamber 14 is simultaneously extracted by the mechanical pump 21, at which time the negative pressure in the check chamber 14 reaches P2; Helium gas is drawn from the actuation chamber 13 by the molecular pump 22, at which point the negative pressure inside the actuation chamber 13 reaches P3; then a determination step is included: Observe the helium concentration value inside the sealing cover 40. If the helium concentration value decreases, there are micropores on the side wall of the check valve 10.

[0048] Specifically, after confirming that the check valve 10 is leak-free through testing procedures, a sealing cover 40 is used to completely enclose the check valve 10, forming a closed testing environment. The sealing cover 40 is filled with helium to avoid interference from external gases and ensure the accuracy of the test results. A helium detector is connected inside the sealing cover 40 to monitor changes in helium concentration in real time. This allows for dynamic tracking of helium concentration changes and rapid response to leakage signals; the recorded helium concentration data provides a basis for subsequent analysis.

[0049] Furthermore, since helium is a small molecule, when the gas in the actuation chamber 13 and check chamber 14 is repeatedly drawn in without the influence of other gases, a negative pressure is formed in the chamber. If there are micropores on the side wall of the check valve 10, helium molecules will enter the actuation chamber 13 and check chamber 14 through the side wall. If the decrease in helium content is detected by the helium detector, it is determined that there are micropores on the side wall of the check valve 10.

[0050] Furthermore, by observing the helium content in the actuation chamber 13 and the check chamber 14, the helium content in the two chambers gradually decreases. When the leakage pressure at the leakage point is reached, the helium content in one or both of the actuation chamber 13 and the check chamber 14 increases simultaneously. This indicates that micropores exist on the sidewalls of one or both of the actuation chamber 13 and the check chamber 14.

[0051] A check valve airtightness testing device 100 includes the aforementioned check valve 10 airtightness testing method, and the testing device further includes: Check valve 10 includes valve body 11 and check element 12 movably connected to valve body 11. The check element 12 is disposed in valve body 11 and divides valve body 11 into an actuation chamber 13 and a check chamber 14. The suction assembly 20 includes a mechanical pump 21 and a molecular pump 22. The mechanical pump 21 is connected to the actuation chamber 13 and the check chamber 14 respectively, and the molecular pump 22 is connected to the actuation chamber 13. The detection component 30 is connected to the suction tube 23 and is used to detect the helium concentration in the check valve 10. The suction assembly 20 further includes a suction tube 23 movably connected to the valve body 11. The suction tube 23 abuts against the inner walls of the check chamber 14 and the actuation chamber 13 respectively, and is used to detect leakage in different areas of the valve body 11.

[0052] Specifically, mechanical pump 21 simultaneously draws in helium, bringing both actuation chamber 13 and check chamber 14 to the set standard working negative pressure for preliminary leak assessment. While mechanical pump 21 draws in helium, helium tracers monitor changes in helium concentration in both chambers. Molecular pump 22 further extracts residual helium from actuation chamber 13, bringing it to an even higher negative pressure, thereby improving the sensitivity to detect minute leaks.

[0053] Furthermore, a helium detector is connected to the suction tube 23 to monitor and record the helium concentration in each cavity inside the check valve 10 in real time. By detecting changes in the helium concentration in the cavities, it is determined whether a leak exists. Because helium molecules are small and diffuse quickly, even a tiny leak will cause a significant change in the helium concentration, providing a highly sensitive leak detection method.

[0054] In one specific embodiment, the suction component can be an integrated vacuum pump that combines the functions of both a mechanical pump and a molecular pump.

[0055] Furthermore, the suction tube 23 is movably connected to the valve body 11 and abuts against the inner walls of the actuation chamber 13 and the check chamber 14, respectively, serving as a passage for suction gas and also as a sampling point for detecting helium concentration. Because the suction tube 23 contacts the inner walls of both chambers, its movable connection allows for testing at different locations. For example, after initial testing, the suction tube 23 can be moved to a cavity port or a specific area to further verify the sealing, achieving comprehensive testing of all areas of the valve body 11. In one specific embodiment, the suction tube 23 includes an integrally formed main body 231 and an elastic layer 232. One end of the elastic layer 232 is disposed at the end of the main body 231, and the other end is inclined outward. The inner surfaces of the check cavity 14 and the actuation cavity 13 both have a stepped surface 50. When the suction tube 23 extends into the valve body 11, the elastic layer 232 abuts against the stepped surface 50. The detection device also includes a sealing cover 40 covering the check valve 10, the sealing cover 40 being connected to the detection component 30 and used to isolate external air.

[0056] Specifically, when the suction tube 23 extends into the valve body 11, the elastic layer 232 abuts against the inner wall of the port. When it enters the actuation chamber 13 or the check chamber 14, the elastic layer 232 pops out, and its outwardly inclined end makes close contact with the stepped surface 50 inside the chamber. At this time, it is fixed to ensure that the suction tube 23 can be fixed in the predetermined position when entering the check chamber 14 and the actuation chamber 13. A good sealing contact is formed between the suction tube 23 and the inner surface of the chamber. When the mechanical pump 21 or the molecular pump 22 is working, the negative pressure generated further presses the elastic part against the stepped surface 50 inside the valve body 11, achieving better sealing and preventing air from escaping through the air between the pipes, thus performing a sealing test in the actuation chamber 13 and the check chamber 14.

[0057] Furthermore, the suction tube 23 is pulled to the port of the valve body 11, and the elastic layer 232 and suction tube 23 are sealed and fixed at the port of the valve body 11. This part is conventional existing technology, and the fixing of the suction tube 23 to the port of the valve body 11 will not be described in detail here. At this time, the suction assembly 20 performs suction, which can detect the sealing condition of the port of the valve body 11. The sealing cover 40 is filled with helium to form a helium chamber. The sealing cover 40 encloses the check valve 10 and creates a relatively independent detection chamber environment. The detection assembly 30 directly detects the helium content in the sealing cover 40, which can directly determine whether there are micropores on the side wall of the check valve 10.

[0058] In summary, the integrated design of the main body 231 and the suction tube 23 with the elastic layer 232, combined with the physical seal formed by the stepped surface 50 inside the cavity, ensures accurate suction positioning and good sealing during the detection process. The sealing cover 40 effectively isolates external air interference, providing a stable and closed environment for detection. The overall system, through the combined suction of the mechanical pump 21 and the molecular pump 22, plus real-time helium concentration monitoring, can achieve highly sensitive detection of different areas of the check valve 10 (including the side wall, the sealing surface of the check element 12, and the port).

[0059] The above description is merely an embodiment of this application. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this application, but these improvements all fall within the protection scope of this application.

Claims

1. A method for testing the airtightness of a check valve, characterized in that, Includes the following steps: A check valve is provided, the check valve including a valve body and a check element disposed in the valve body, the valve body having a working chamber communicating with the outside, the check element dividing the working chamber into an actuating chamber and a check chamber, the opening pressure of the check element being P, the standard working negative pressure of the mechanical pump being PJ, the standard working negative pressure of the molecular pump being PF, PF > P > PJ, and the actuating chamber and the check chamber being respectively connected to a helium detector; The mechanical pump simultaneously connects and seals the actuation chamber and the check chamber, and injects helium into the actuation chamber, at which point the gas pressure in the actuation chamber rises to P1; The mechanical pump simultaneously extracts the gas present in the actuation chamber and the check chamber, at which time the negative pressure in the check chamber reaches P2; Helium gas is drawn from the actuation chamber by the molecular pump, at which point the negative pressure in the actuation chamber reaches P3; Compare P2 and PJ. If P2 = PJ, and the helium content in the check chamber slowly decreases to a stable state, it is determined that the check chamber has no leakage. Otherwise, the location of the leakage point is determined based on the change in helium concentration and the comparison result of P2 and PJ. Compare P3 and PF. If P3 = PF and the helium content in the actuation chamber continuously decreases to a stable state, it is determined that there is no leakage in the actuation chamber. Otherwise, the location of the leakage point is determined based on the change in helium concentration and the comparison results of P3 and PF.

2. The method for testing the airtightness of a check valve according to claim 1, characterized in that, The step "Compare P2 and PJ. If P2 = PJ, and the helium content in the check cavity slowly decreases to a stable state, it is determined that the check cavity has no leakage; otherwise, the location of the leak point is determined based on the helium concentration change and the comparison result of P2 and PJ" also includes a determination step: If the comparison result is P2 < PJ, and the helium content slowly decreases until it reaches a stable state, then the sidewall of the check cavity leaks.

3. The method for testing the airtightness of a check valve according to claim 1, characterized in that, The step "Compare P2 and PJ. If P2 = PJ, and the helium content in the check chamber slowly decreases to a stable state, it is determined that the check chamber has no leakage; otherwise, the location of the leak point is determined based on the helium concentration change and the comparison result of P2 and PJ" also includes a determination step: If the comparison result is P2 < PJ, and the helium content decreases slowly and then increases, then the check valve on one side of the actuation cavity leaks.

4. The method for testing the airtightness of a check valve according to claim 1, characterized in that, The step "Compare P3 and PF. If P3 = PF, and the helium content in the actuation chamber continuously decreases to a stable state, it is determined that there is no leakage in the actuation chamber; otherwise, the location of the leak point is determined based on the helium concentration change and the comparison result of P3 and PF" also includes a determination step: If the comparison result is P3 < PF, the helium content in the actuation chamber continues to decrease to a stable state, and the helium content in the check chamber remains stable, then the sidewall of the actuation chamber leaks.

5. The method for testing the airtightness of a check valve according to claim 1, characterized in that, The step "Compare P3 and PF. If P3 = PF, and the helium content in the actuation chamber continuously decreases to a stable state, it is determined that there is no leakage in the actuation chamber; otherwise, the location of the leak point is determined based on the helium concentration change and the comparison result of P3 and PF" also includes a determination step: If the comparison result is P3 < PF, and the helium content in the actuation chamber continues to decrease to a stable state, then decreases again and remains stable, and the helium content in the check chamber decreases, then the check valve on one side of the check chamber leaks.

6. The method for testing the airtightness of a check valve according to claim 1, characterized in that, When it is determined that there is no leakage in the check chamber and the actuation chamber, move the connection ends of the mechanical pump and the molecular pump with the check valve to the ports of the actuation chamber and the check chamber; Repeat the step "simultaneously extract the gas present in the actuation chamber and the check chamber by the mechanical pump, at which time the negative pressure in the check chamber reaches P2; Helium gas is drawn from the actuation chamber by the molecular pump, at which point the negative pressure inside the actuation chamber reaches P3; then, a determination step is included: Compare P2 and PJ. If the comparison result is P2 < PJ, then it is determined that the check cavity port is leaking. Compare P3 and PF. If the comparison result is P3 < PF, it is determined that the actuation cavity port has leaked.

7. The method for testing the airtightness of a check valve according to claim 1, characterized in that, When it is determined that there is no leakage in the check chamber and the actuation chamber, a sealing cover is provided to cover the check valve, helium is injected into the sealing cover and a helium detector is connected, and the step of "simultaneously extracting the gas in the actuation chamber and the check chamber by the mechanical pump" is repeated, at which time the negative pressure in the check chamber reaches P2. Helium gas is drawn from the actuation chamber by the molecular pump, at which point the negative pressure inside the actuation chamber reaches P3; then, a determination step is included: Observe the helium concentration inside the sealing cover. If the helium concentration decreases, there are micropores on the side wall of the check valve.

8. The method for testing the airtightness of a check valve according to claim 1, characterized in that, Repeat the steps in claim 1 to prevent accidental errors in the detection.

9. A check valve airtightness testing device, comprising a check valve airtightness testing method as described in any one of claims 1-8, characterized in that, The detection device further includes: A check valve includes a valve body and a check element movably connected to the valve body. The check element is disposed in the valve body and divides the valve body into an actuating chamber and a check chamber. The suction assembly includes a mechanical pump, a molecular pump, and a suction tube. The mechanical pump is connected to the actuation chamber and the check chamber, respectively, and the molecular pump is connected to the actuation chamber. A detection component, connected to the suction tube, is used to detect the helium concentration inside the check valve; The suction tube is movably connected to the valve body, and the suction tube abuts against the inner walls of the check cavity and the actuation cavity respectively, for detecting leakage in different areas of the valve body.

10. A check valve airtightness testing device according to claim 9, characterized in that, The suction tube includes an integrally formed main body and an elastic layer. One end of the elastic layer is located at the end of the main body, and the other end is inclined outward. The inner surfaces of the check cavity and the actuation cavity both have a stepped surface. When the suction tube is inserted into the valve body, the elastic layer abuts against the stepped surface. The detection device also includes a sealing cover over the check valve, the sealing cover being connected to the detection component and used to isolate external air.

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