Check valve airtightness detection device and method

Abstract

The invention provides a check valve airtightness detection method, which comprises the following steps that: a mechanical pump simultaneously communicates with and blocks an actuating cavity and a check cavity, and injects helium into the actuating cavity, and at the moment, the air pressure of the actuating cavity is increased to P1; gas in the actuating cavity and the non-return cavity is extracted at the same time through a mechanical pump, and at the moment, the negative pressure in the non-return cavity reaches P2; the helium in the actuating cavity is extracted through the molecular pump, and at the moment, the negative pressure in the non-return cavity reaches P3; p2 and PJ are compared, and if P2 is equal to PJ and the helium content in the non-return cavity is slowly reduced to a stable state, it is judged that no leakage exists in the non-return cavity; and comparing P3 with PF, and if P3 is equal to PF and the helium content in the actuating cavity is continuously reduced to a stable state, judging that the actuating cavity has no leakage. According to the check valve airtightness detection device and method, the dynamic condition of the check valve in the working process is simulated through the negative pressure suction mode of the mechanical pump and the molecular pump, and high-sensitivity leakage detection of the check cavity and the actuating cavity is achieved in cooperation with the helium tester in the one-time testing process.

Description

Technical Field

[0001] This application relates to the field of airtightness detection, and particularly to an airtightness detection device and method for a check valve. Background Art

[0002] As a key component in a fluid control system, the airtightness of the valve body directly affects the operating stability and safety of the system. In industries, medical, automotive, aerospace and other fields, high requirements are placed on the sealing performance of the valve body. Especially in high-pressure or negative-pressure environments, any minor leakage may lead to reduced system efficiency, increased energy consumption, and even affect the normal operation of the equipment.

[0003] The existing airtightness detection of one-way valves usually adopts the high-pressure gas detection method, that is, high-pressure gas is introduced into the inlet end and the outlet end of the valve respectively to test the sealing condition of the valve. This method requires two independent tests respectively to determine the leakage conditions at both ends of the one-way valve.

[0004] The existing airtightness detection methods for one-way valves have several defects: First, since it is necessary to maintain the pressure change in the detection chamber for a period of time after charging high-pressure gas to identify whether there is a leakage point, and it is also necessary to test twice respectively to judge the sealing conditions at both ends, the detection cycle is long, and for the case of minor leakage points, the pressure change is not obvious, resulting in inaccurate detection results. Summary of the Invention

[0005] In view of this, it is necessary to provide an airtightness detection device and method for a check valve that are simple to detect and have a fast response to solve the above problems.

[0006] An embodiment of this application provides an airtightness detection method for a check valve, including the following steps:

[0007] Provide a check valve, the check valve includes a valve body and a check member provided in the valve body, the valve body is provided with a working chamber communicating with the outside, the check member divides the working chamber into an actuating chamber and a check chamber, the opening pressure of the check member is P, the standard working negative pressure of the mechanical pump is PJ, the standard working negative pressure of the molecular pump is PF, PF > P > PJ, and helium detectors are respectively connected to the actuating chamber and the actuating chamber;

[0008] The mechanical pump is simultaneously connected to and blocks the actuating chamber and the check chamber, and helium gas is injected into the actuating chamber, and at this time the air pressure in the actuating chamber rises to P1;

[0009] The mechanical pump simultaneously extracts the gas existing in the actuating chamber and the check chamber, and at this time the negative pressure in the check chamber reaches P2;

[0010] The molecular pump extracts the helium gas in the actuating chamber, and at this time the negative pressure in the check chamber reaches P3;

[0011] Compare P2 with PJ. If P2 = PJ and the helium content in the check valve cavity slowly decreases to a stable state, it is determined that there is no leakage in the check valve cavity; otherwise, based on the change in helium concentration and the comparison result between P2 and PJ, the location of the leakage point is obtained.

[0012] Compare P3 with PF. If P3 = PF and the helium content in the actuating cavity continuously decreases to a stable state, it is determined that there is no leakage in the actuating cavity; otherwise, based on the change in helium concentration and the comparison result between P3 and PF, the location of the leakage point is obtained.

[0013] In at least one embodiment of the present application, the step "Compare P2 with PJ. If P2 = PJ and the helium content in the check valve cavity slowly decreases to a stable state, it is determined that there is no leakage in the check valve cavity; otherwise, based on the change in helium concentration and the comparison result between P2 and PJ, the location of the leakage point is obtained." further includes a determination step:

[0014] If the comparison result is P2 < PJ and the helium content slowly decreases and then remains stable, then there is a leakage in the side wall of the check valve cavity.

[0015] In at least one embodiment of the present application, the step "Compare P2 with PJ. If P2 = PJ and the helium content in the check valve cavity slowly decreases to a stable state, it is determined that there is no leakage in the check valve cavity; otherwise, based on the change in helium concentration and the comparison result between P2 and PJ, the location of the leakage point is obtained." further includes a determination step:

[0016] 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 on one side of the actuating cavity.

[0017] In at least one embodiment of the present application, the step "Compare P3 with PF. If P3 = PF and the helium content in the actuating cavity continuously decreases to a stable state, it is determined that there is no leakage in the actuating cavity; otherwise, based on the change in helium concentration and the comparison result between P3 and PF, the location of the leakage point is obtained." further includes a determination step:

[0018] If the comparison result is P3 < PJ, the helium content in the actuating cavity continuously decreases to a stable state, and the helium content in the check valve cavity remains stable, then there is a leakage in the side wall of the actuating cavity.

[0019] In at least one embodiment of the present application, the step "Compare P3 with PF. If P3 = PF and the helium content in the actuating cavity continuously decreases to a stable state, it is determined that there is no leakage in the actuating cavity; otherwise, based on the change in helium concentration and the comparison result between P3 and PF, the location of the leakage point is obtained." further includes a determination step:

[0020] If the comparison result is P3 < PF, and after the helium content in the actuation chamber continuously decreases to a stable state and then decreases again and remains stable, and the helium content in the check valve chamber decreases, then the check valve on the side of the check valve chamber leaks.

[0021] In at least one embodiment of the present application, when it is determined that there is no leakage in the check valve chamber and the actuation chamber, move the connection ends of the mechanical pump and the molecular pump to the ports of the actuation chamber and the check valve chamber with the check valve;

[0022] Repeat the step "Simultaneously extract the gas present in the actuation chamber and the check valve chamber through the mechanical pump, and at this time, the negative pressure in the check valve chamber reaches P2;

[0023] Extract the helium gas in the actuation chamber through the molecular pump, and at this time, the negative pressure in the check valve chamber reaches P3;". After that, it further includes a determination step:

[0024] Compare P2 with PJ. If the comparison result is P2 < PJ, then it is determined that the port of the check valve chamber leaks;

[0025] Compare P3 with PF. If the comparison result is P3 < PF, then it is determined that the port of the actuation chamber leaks.

[0026] In at least one embodiment of the present application, when it is determined that there is no leakage in the check valve chamber and the actuation chamber, provide a sealing cover to cover the check valve, inject helium gas into the sealing cover, and connect a helium detector. Repeat the step "Simultaneously extract the gas present in the actuation chamber and the check valve chamber through the mechanical pump, and at this time, the negative pressure in the check valve chamber reaches P2;

[0027] Extract the helium gas in the actuation chamber through the molecular pump, and at this time, the negative pressure in the check valve chamber reaches P3;". After that, it further includes a determination step:

[0028] Observe the helium concentration value in the sealing cover. If the helium concentration value decreases, there are micropores on the side wall of the check valve.

[0029] In at least one embodiment of the present application, repeat the steps in claim 1 to prevent accidental errors in detection.

[0030] A check valve airtightness inspection device includes a check valve airtightness detection method as described in any one of the above, and the detection device further includes:

[0031] A check valve, including a valve body and a check valve element movably connected to the valve body. The check valve element is arranged in the valve body and divides the valve body into an actuation chamber and a check valve chamber;

[0032] The suction assembly includes a mechanical pump and a molecular pump. The mechanical pump is respectively connected to the actuating chamber and the check chamber, and the molecular pump is connected to the actuating chamber.

[0033] The detection assembly is connected to the suction pipe and is used to detect the helium concentration in the check valve.

[0034] Wherein, the suction assembly further includes a suction pipe movably connected to the valve body. The suction pipe abuts against the inner walls of the check chamber and the actuating chamber respectively, and is used to detect the leakage conditions in different regions of the valve body.

[0035] In at least one embodiment of the present application, the suction pipe includes a main body and an elastic layer. One end of the elastic layer is arranged on the main body, and the other end is inclined outward. Both the inner surfaces of the check chamber and the actuating chamber have a step surface. When the suction pipe extends into the valve body, the elastic layer abuts against the step surface.

[0036] The detection device further includes a sealing cover covering the check valve. The sealing cover is connected to the detection assembly and is used to isolate external air.

[0037] The provided check valve airtightness detection device and method complete the leakage detection of the check chamber and the actuating chamber in one test through the combined suction of a mechanical pump and a molecular pump. The cooperation of the molecular pump and the mechanical pump simulates the dynamic situation during the operation of the one-way valve. The negative pressure suction method is used for detection. Helium is used as the tracer gas. Utilizing the high diffusivity and low background concentration characteristics of helium molecules, combined with a helium detector, high-sensitivity leakage detection is achieved, with a faster response speed, and it can accurately identify tiny leakage points, improving the detection accuracy. Description of the Drawings

[0038] Figure 1 It is a flow step block diagram of a check valve airtightness detection method according to an application of the present application.

[0039] Figure 2 It is Figure 1 The check chamber leakage determination step block diagram of the described check valve airtightness detection method.

[0040] Figure 3 It is Figure 1 The actuating chamber leakage determination step block diagram of the described check valve airtightness detection method.

[0041] Figure 4 It is a perspective view of a check valve airtightness detection device in an embodiment of the present application.

[0042] Figure 5 It is Figure 4 The sectional view of the described check valve airtightness detection device.

[0043] Figure 6 For Figure 5 The enlarged view of part A of the airtightness detection device for a check valve as described above.

[0044] Description of main component symbols

[0045] 100. An airtightness detection device for a check valve; 10. Check valve; 11. Valve body; 12. Check member; 13. Actuating cavity; 14. Check cavity; 20. Suction assembly; 21. Mechanical pump; 22. Molecular pump; 23. Suction pipe; 231. Main body; 232. Elastic layer; 30. Detection assembly; 40. Sealing cover; 50. Step surface. Specific embodiments

[0046] The following will describe the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments.

[0047] 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 there may be an intermediate component at the same time. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. The terms "top", "bottom", "upper", "lower", "left", "right", "front", "rear", and similar expressions used herein are only for the purpose of illustration.

[0048] The embodiments of the present application provide an airtightness detection method for a check valve, including the following steps:

[0049] Provide a check valve, the check valve includes a valve body and a check member disposed in the valve body, the valve body is provided with a working cavity communicating with the outside, the check member divides the working cavity into an actuating cavity and a check cavity, the opening pressure of the check member is P, the standard working negative pressure of the mechanical pump is PJ, the standard working negative pressure of the molecular pump is PF, PF > P > PJ, and helium detectors are respectively connected to the actuating cavity and the check cavity;

[0050] The mechanical pump simultaneously communicates with and seals the actuating cavity and the check cavity, and injects helium gas into the actuating cavity. At this time, the air pressure in the actuating cavity rises to P1;

[0051] Simultaneously extract the existing gas in the actuating cavity and the check cavity through the mechanical pump. At this time, the negative pressure in the check cavity reaches P2;

[0052] Extract the helium gas in the actuating cavity through the molecular pump. At this time, the negative pressure in the check cavity reaches P3;

[0053] Compare P2 with PJ. If P2 = PJ and the helium content in the check valve cavity slowly decreases to a stable state, it is determined that there is no leakage in the check valve cavity. Otherwise, based on the change in helium concentration and the comparison result of P2 and PJ, the location of the leakage point is obtained;

[0054] Compare P3 with PF. If P3 = PF and the helium content in the actuator cavity continuously decreases to a stable state, it is determined that there is no leakage in the actuator cavity. Otherwise, based on the change in helium concentration and the comparison result of P3 and PF, the location of the leakage point is obtained.

[0055] The provided check valve airtightness detection device and method complete the leakage detection of the check valve cavity and the actuator cavity in one test through the combined suction of a mechanical pump and a molecular pump. The cooperation of the molecular pump and the mechanical pump simulates the dynamic situation during the operation of the one-way valve. The negative pressure suction method is used for detection. Helium is used as the tracer gas. Utilizing the high diffusivity and low background concentration characteristics of helium molecules, combined with a helium detector, high-sensitivity leakage detection is achieved, with a faster response speed and the ability to accurately identify tiny leakage points, improving the detection accuracy.

[0056] The following will, with reference to the accompanying drawings, elaborate on some embodiments of the present application. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0057] Please refer to Figures 1-6 , the embodiments of the present application provide a method for detecting the airtightness of a check valve 10, including the following steps:

[0058] Provide a check valve 10, which includes a valve body 11 and a check member 12 disposed inside the valve body 11. The valve body 11 is provided with a working cavity communicating with the outside. The check member 12 divides the working cavity into an actuator cavity 13 and a check valve cavity 14. The opening pressure of the check member 12 is P, the standard working negative pressure of the mechanical pump 21 is PJ, and the standard working negative pressure of the molecular pump 22 is PF, where PF > P > PJ. Helium detectors are respectively connected to the actuator cavity 13 and the check valve cavity 13;

[0059] The mechanical pump 21 simultaneously communicates with and seals the actuator cavity 13 and the check valve cavity 14, and injects helium into the actuator cavity 13. At this time, the air pressure in the actuator cavity 13 rises to P1;

[0060] The mechanical pump 21 simultaneously extracts the gas existing in the actuator cavity 13 and the check valve cavity 14. At this time, the negative pressure in the check valve cavity 14 reaches P2;

[0061] The molecular pump 22 extracts the helium in the actuator cavity 13. At this time, the negative pressure in the check valve cavity 14 reaches P3;

[0062] Compare P2 with PJ. If P2 = PJ and the helium content in the check valve cavity 14 slowly decreases to a stable state, it is determined that there is no leakage in the check valve cavity 14. Otherwise, based on the change in helium concentration and the comparison result between P2 and PJ, the location of the leakage point is obtained.

[0063] Compare P3 with PF. If P3 = PF and the helium content in the actuating cavity 13 continuously decreases to a stable state, it is determined that there is no leakage in the actuating cavity 13. Otherwise, based on the change in helium concentration and the comparison result between P3 and PF, the location of the leakage point is obtained.

[0064] Specifically, set the working negative pressure PF of the molecular pump 22 to be higher than the opening pressure P of the check valve member 12 to ensure that the check valve member 12 will not be accidentally opened during the test, affecting the test results. The cavities on both sides are in a static sealed state, simulating the state of the check valve 10 during operation. Ensure that the check valve member 12 is in a closed state throughout the test process, so that the actuating cavity 13 and the check valve cavity 14 can be independently tested, improving the test accuracy. The mechanical pump 21 is connected to and blocks the actuating cavity 13 and the check valve cavity 14, and injects helium into the actuating cavity 13 to raise the air pressure in the actuating cavity 13 to P1 to simulate the air pressure condition of the check valve 10 in the working state, and fills the actuating cavity 13 with the tracer gas helium. Helium is used as the tracer gas. Due to its small molecules and strong diffusivity, it can quickly penetrate into tiny gaps, improving the sensitivity of leak detection.

[0065] Furthermore, the mechanical pump 21 extracts the gas from both cavities to make the check valve cavity 14 reach the negative pressure P2, simulating the leakage situation during normal operation. When P2 is equal to the standard working negative pressure PJ, it indicates that there is no leakage point in the check valve cavity 14. The helium content in the check valve cavity 14 is partially extracted by the mechanical pump 21, and the helium detector shows a curve of decreasing helium. When the mechanical pump 21 reaches the working negative pressure, the mechanical pump 21 cannot continue to extract the air in the check valve cavity 14, and the helium content remains stable.

[0066] Still further, the mechanical pump 21 first extracts the air in the actuating cavity 13 and the check valve cavity 14, greatly reducing the air content in the cavities. Through the suction of the mechanical pump 21, the large-molecule gases in the cavities are preferentially removed. Helium has strong adhesion and is an inert gas, and the residual gas is mainly helium. The pumping speed of the molecular pump 22 is much higher than that of the mechanical pump 21, and it can achieve a higher vacuum degree. The molecular pump 22 further extracts the residual helium to reach the negative pressure P3. When P3 is equal to the working negative pressure PF, it indicates that there is no leakage point in the actuating cavity 13. The helium detector shows a curve of decreasing helium. When the molecular pump 22 reaches the working negative pressure, the molecular pump 22 cannot continue to extract the helium in the check valve cavity 14, and the helium content remains stable.

[0067] In summary, through the combined suction design of the mechanical pump 21 and the molecular pump 22, the airtightness detection of the check valve 10 only requires one step to complete the test. Helium molecules are small and have strong diffusivity, and can quickly penetrate into tiny gaps. Combining with the low background concentration detection ability of the helium detector, ppm-level leak identification can be achieved. By simulating the real working conditions and the dual determination logic of pressure and helium concentration, high-sensitivity and high-precision detection of the airtightness of the check valve 10 is realized.

[0068] In a specific embodiment, the step of "comparing P2 with PJ. If P2 = PJ and the helium content in the check cavity 14 slowly decreases to a stable state, it is determined that there is no leak in the check cavity 14; otherwise, according to the change in helium concentration and the comparison result of P2 and PJ, the position of the leak point is obtained." further includes a determination step:

[0069] If the comparison result is P2 < PJ and the helium content slowly decreases to maintain a stable state, then the side wall of the check cavity 14 leaks.

[0070] Specifically, P2 is the actual negative pressure value reached by the check cavity 14 after the mechanical pump 21 extracts the gas in the actuating cavity 13 and the check cavity 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 cavity 14 has not reached the theoretical value and there is a gas leak. The actual negative pressure in the check cavity 14 is lower than the theoretical working negative pressure of the mechanical pump 21, indicating that external gas enters the check cavity 14 through the leak point, resulting in a pressure rise.

[0071] Furthermore, due to the continuous suction of the mechanical pump 21, the helium concentration in the check cavity 14 will gradually decrease. When the working negative pressure reaches the leakage pressure of the leak point, external air slowly enters the check cavity 14 through the leak 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 stable curve concentration value of the helium concentration at this time is higher than the helium concentration value without leakage in the check cavity 14.

[0072] In a specific embodiment, the step of "comparing P2 with PJ. If P2 = PJ and the helium content in the check cavity 14 slowly decreases to a stable state, it is determined that there is no leak in the check cavity 14; otherwise, according to the change in helium concentration and the comparison result of P2 and PJ, the position of the leak point is obtained." further includes a determination step:

[0073] If the comparison result is P2 < PJ and the helium content slowly decreases and then increases, then the check member 12 on one side of the check cavity 14 leaks.

[0074] Specifically, similar to the above determination steps, if P2 < PJ, it indicates that the negative pressure in the check cavity 14 has not reached the theoretical value, and there is gas leakage. The actual negative pressure in the check cavity 14 is lower than the theoretical working negative pressure of the mechanical pump 21, indicating that external gas enters the check cavity 14 through the leakage point, resulting in a pressure rise. Observe the helium content in the helium detector. The mechanical pump 21 pumps the air in the check cavity 14, and the helium content continuously decreases. When the negative pressure reaches the leakage pressure of the leakage point, the air in the actuating cavity 13 leaks into the check cavity 14. Since the helium concentration in the actuating cavity 13 is greater than the helium concentration in the check cavity 14, the helium content rises after the decrease, indicating that the sealing surface of the check member 12 on one side of the check cavity 14 has leaked.

[0075] In a specific embodiment, the step "Compare P3 with PF. If P3 = PF and the helium content in the actuating cavity 13 continuously decreases to a stable state, it is determined that there is no leakage in the actuating cavity 13. Otherwise, based on the change in helium concentration and the comparison result of P3 and PF, the position of the leakage point is obtained." further includes a determination step:

[0076] If the comparison result is P3 < PJ, the helium content in the actuating cavity 13 continuously decreases to a stable state, and the helium content in the check cavity 14 remains in a stable state, then the side wall of the actuating cavity 13 leaks.

[0077] Specifically, P3 is the actual negative pressure value reached by the check cavity 14 after the molecular pump 22 pumps the helium in the actuating cavity 13; PF is the standard working negative pressure (expected value) of the molecular pump 22. P3 < PJ indicates that the actual negative pressure in the actuating cavity 13 is lower than the theoretical working negative pressure of the molecular pump 22, indicating that external gas enters the actuating cavity 13 through the leakage point, resulting in a pressure rise. Observe the helium content in the helium detector. The helium concentration in the actuating cavity 13 continuously decreases to a stable state, and the helium concentration in the check cavity 14 remains stable, indicating that the gas on one side of the check cavity 14 does not flow into the actuating cavity 13, and it is determined that the side wall of the actuating cavity 13 leaks.

[0078] In a specific embodiment, the step "Compare P3 with PF. If P3 = PF and the helium content in the actuating cavity 13 continuously decreases to a stable state, it is determined that there is no leakage in the actuating cavity 13. Otherwise, based on the change in helium concentration and the comparison result of P3 and PF, the position of the leakage point is obtained." further includes a determination step:

[0079] If the comparison result is P3 < PF, and after the helium content in the actuating cavity 13 continuously decreases to a stable state, it decreases again and remains stable, and the helium content in the check cavity 14 decreases, then the check member 12 on one side of the check cavity 14 leaks.

[0080] Specifically, P3 < PF indicates that the negative pressure in the actuating chamber 13 has not reached the theoretical value, indicating gas leakage. The molecular pump 22 pumps out the remaining helium gas in the actuating chamber 13. As the helium content continuously decreases, when the negative pressure reaches the leakage pressure at the leakage point, the air in the actuating chamber 13 leaks into the check chamber 14. At this time, the helium content in the actuating chamber 13 increases, and on the side of the check chamber 14, the helium content decreases. At this time, leakage occurs at the sealing surface of the check member 12 on the side of the actuating chamber 13.

[0081] In a specific embodiment, when it is determined that there is no leakage in the check valve 10 and the pressure relief valve, 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 chamber 14 with respect to the check valve 10.

[0082] Repeat the step of "simultaneously pumping the gas present in the actuating chamber 13 and the check chamber 14 through the mechanical pump 21, and at this time, the negative pressure in the check chamber 14 reaches P2;

[0083] Pumping out the helium gas in the actuating chamber 13 through the molecular pump 22, and at this time, the negative pressure in the check chamber 14 reaches P3;". After that, it further includes a determination step:

[0084] Compare P2 with PJ. If the comparison result is P2 < PJ, it is determined that there is a leakage at the port of the check chamber 14;

[0085] Compare P3 with PF. If the comparison result is P3 < PF, it is determined that there is a leakage at the port of the actuating chamber 13.

[0086] Specifically, after determining that there is no leakage, move the connection ends of the mechanical pump 21 and the molecular pump 22 from the valve body 11 of the check valve 10 to the ports of the actuating chamber 13 and the check chamber 14 to directly detect the airtightness of the ports. Repeat the pumping steps of the mechanical pump 21 and the molecular pump 22 to ensure that the detection conditions are the same as those for detecting the valve body 11, and avoid misjudgment caused by operation differences.

[0087] Furthermore, if the actual negative pressure at the port of the check chamber 14 is lower than the theoretical working negative pressure of the mechanical pump 21, it indicates that external gas enters the check chamber 14 through the port leakage point, resulting in a pressure rise. If the actual negative pressure at the port of the check chamber 14 is lower than the theoretical working negative pressure of the molecular pump 22, it indicates that external gas enters the check chamber 14 through the port leakage point, resulting in a pressure rise. Since it has been determined that there is no leakage in the actuating chamber 13 and the check chamber 14, if the pressure shows an abnormality, it means that there is a leakage at the corresponding port.

[0088] Still further, repeat all the steps of detecting the check chamber 14, the actuating chamber 13, and their ports, and compare the results of multiple times to prevent mismeasurement caused by chance.

[0089] In a specific embodiment, when it is determined that the check valve 10 and the pressure relief valve have no leakage, a sealing cover 40 is provided to cover the check valve 10, helium gas is injected into the sealing cover 40, and a helium detector is connected. Repeat the steps "Simultaneously extract the gas present in the actuating chamber 13 and the check chamber 14 through the mechanical pump 21, and at this time, the negative pressure in the check chamber 14 reaches P2;

[0090] Extract the helium gas in the actuating chamber 13 through the molecular pump 22, and at this time, the negative pressure in the check chamber 14 reaches P3;". After that, a determination step is further included:

[0091] Observe the helium gas concentration value in the sealing cover 40. If the helium gas concentration value decreases, there are micropores on the side wall of the check valve 10.

[0092] Specifically, after it is determined that the check valve 10 has no leakage through the test steps, the check valve 10 is completely covered with the sealing cover 40 to form a closed detection environment. The sealing cover 40 is filled with helium gas to avoid interference from external gases and ensure the accuracy of the detection results; a helium detector is connected inside the sealing cover 40 to monitor the change in helium gas concentration in real time. It can dynamically track the change in helium gas concentration and quickly respond to leakage signals; by recording the helium gas concentration data, it provides a basis for subsequent analysis.

[0093] Furthermore, helium is a small-sized molecule. Without the influence of other gases, when the gas in the actuating chamber 13 and the check chamber 14 is repeatedly pumped out and a negative pressure is formed in the chamber, if there are micropores on the side wall of the check valve 10, the helium molecules will enter the actuating chamber 13 and the check chamber 14 through the side wall. If the decrease in the helium content is detected by the helium detector, it is determined that there are micropores on the side wall of the check valve 10.

[0094] Still further, observe the helium content in the actuating 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, if the helium content in one or both of the actuating chamber 13 and the check chamber 14 rises simultaneously, it can be respectively determined that there are micropores on the side wall of one or both of the actuating chamber 13 and the check chamber 14.

[0095] A check valve airtightness detection device 100 includes the above-mentioned check valve 10 airtightness detection method. The detection device further includes:

[0096] A check valve 10, including a valve body 11 and a check member 12 movably connected to the valve body 11. The check member 12 is disposed inside the valve body 11 and divides the valve body 11 into an actuating chamber 13 and a check chamber 14;

[0097] The suction assembly 20 includes a mechanical pump 21 and a molecular pump 22. The mechanical pump 21 is respectively connected to the actuating chamber 13 and the check chamber 14, and the molecular pump 22 is connected to the actuating chamber 13;

[0098] The detection assembly 30 is connected to the suction pipe 23 and is used to detect the helium concentration in the check valve 10;

[0099] Wherein, the suction assembly 20 further includes a suction pipe 23 movably connected to the valve body 11. The suction pipe 23 abuts against the inner walls of the check chamber 14 and the actuating chamber 13 respectively, and is used to detect the leakage conditions of different regions of the valve body 11.

[0100] Specifically, the mechanical pumps 21 suck simultaneously, so that the actuating chamber 13 and the check chamber 14 reach the set standard working negative pressure simultaneously, for preliminarily judging the leakage conditions. While the mechanical pumps 21 are sucking, through helium tracing, the change of the helium concentration in the two chambers can be monitored. The molecular pump 22 further extracts the residual helium from the actuating chamber 13, so that the actuating chamber 13 reaches a higher negative pressure, thereby improving the detection sensitivity for minute leaks.

[0101] Further, a helium detector is connected to the suction pipe 23 and is used to monitor and record the helium concentration in each chamber inside the check valve 10 in real time. By detecting the change of the helium concentration in the chamber, it is judged whether there is a leak. Since the helium molecules are small in volume and fast in diffusion speed, even a minute leak will cause an obvious change in the helium concentration, providing a high-sensitivity leak detection means.

[0102] In a specific embodiment, the suction assembly can be an integrated vacuum pump, and the functions of both the mechanical pump and the molecular pump are integrated in the vacuum pump.

[0103] Still further, the suction pipe 23 is movably connected to the valve body 11 and abuts against the inner walls of the actuating chamber 13 and the check chamber 14 respectively. As a passage for sucking gas, it also serves as a sampling point for detecting the helium concentration. Since the suction pipe 23 contacts the inner walls of the two chambers respectively, the movable connection mode of the suction pipe 23 allows detection at different positions. For example, after preliminary detection, the suction pipe 23 is moved to the chamber port or a local area to further verify the sealing condition, realizing a comprehensive detection of each region of the valve body 11.

[0104] In a specific embodiment, the suction pipe 23 includes a main body 231 and an elastic layer 232 which are integrally arranged. One end of the elastic layer 232 is arranged at the end of the main body 231, and the other end is inclined outward. A step surface 50 is provided on the inner surfaces of both the check chamber 14 and the actuating chamber 13. When the suction pipe 23 extends into the valve body 11, the elastic layer 232 abuts against the step surface 50;

[0105] The detection device further includes a sealing cover 40 covering the check valve 10. The sealing cover 40 is connected to the detection component 30 and is used to isolate external air.

[0106] Specifically, when the suction pipe 23 extends into the valve body 11, the elastic layer 232 abuts against the inner wall of the port. When entering the actuating cavity 13 or the check cavity 14, the elastic layer 232 pops out and tightly contacts the step surface 50 in the cavity through its outwardly inclined end. At this time, it is ensured that the suction pipe 23 can be fixed at a predetermined position when entering the check cavity 14 and the actuating cavity 13. A good sealing contact is formed between the suction pipe 23 and the inner surface of the cavity. When the mechanical pump 21 or the molecular pump 22 is working, the negative pressure generated further presses the elastic part against the step surface 50 in the valve body 11 to achieve better sealing and prevent air in the cavity from overflowing through the air between the pipes, so as to detect the sealing performance in the actuating cavity 13 and the check cavity 14.

[0107] Further, the suction pipe 23 is pulled to the position of the port of the valve body 11, and the elastic layer 232 seals and fixes the suction pipe 23 at the port of the valve body 11. This part is conventional prior art, and the fixation of the suction pipe 23 and the port of the valve body 11 will not be elaborated here. At this time, the suction assembly 20 performs suction, and the sealing condition of the port of the valve body 11 can be detected. Helium gas is filled in the sealing cover 40 to form a helium gas cavity. The sealing cover 40 wraps the check valve 10 to create a relatively independent detection cavity environment. The detection component 30 directly detects the helium gas content in the sealing cover 40, and the presence or absence of micropores on the side wall of the check valve 10 can be obtained intuitively.

[0108] In summary, the design of the suction pipe 23 with the integrally arranged main body 231 and the elastic layer 232, combined with the physical seal formed by the step surface 50 in the cavity, ensures accurate suction positioning and good sealing performance during the detection process; while the sealing cover 40 effectively isolates external air interference and provides a stable and closed environment for the detection. The overall system can achieve highly sensitive detection of different regions (including the side wall, the sealing surface of the check member 12 and the port) of the check valve 10 through the combined suction of the mechanical pump 21 and the molecular pump 22, plus real-time monitoring of the helium gas concentration.

[0109] The above are only the implementation manners of the present application. It should be noted here that for those of ordinary skill in the art, improvements can be made without departing from the creative concept of the present application, but these all belong to the protection scope of the present application.

Claims

1. A method for detecting air tightness of a check valve, characterized in that: The steps include: A check valve is provided, the check valve comprising a valve body and a check member arranged in the valve body, the valve body is provided with a working chamber connected to the outside, the check member divides the working chamber into an actuating chamber and a check chamber, the opening pressure of the check member is P, the standard working negative pressure of a mechanical pump is PJ, the standard working negative pressure of a molecular pump is PF, PF>P>PJ, the actuating chamber and the actuating chamber are respectively connected to a helium detector; The mechanical pump simultaneously connects and blocks the actuating chamber and the check chamber, and injects helium into the actuating chamber. At this time, the air pressure in the actuating chamber rises to P1; The mechanical pump simultaneously extracts the gas in the actuating chamber and the check chamber, and the negative pressure in the check chamber reaches P2; The helium in the actuating chamber is extracted by the molecular pump, and the negative pressure in the check chamber reaches P3; Compare P2 with 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 obtained according to the change in helium concentration and the comparison result of P2 and PJ. Compare P3 with PF. If P3=PF and the helium content in the actuating chamber continues to decrease to a stable state, it is determined that there is no leakage in the actuating chamber. Otherwise, the location of the leakage point is obtained based on the change in helium concentration and the comparison result of P3 and PF.

2. A check valve air tightness detection method according to claim 1, characterized in that: The step "compare P2 with 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 obtained according to the change in helium concentration and the comparison result of P2 and PJ." also includes the determination step: If the comparison result is P2<PJ, and the helium content slowly decreases to maintain a stable state, then the side wall of the check chamber leaks.

3. A check valve air tightness detection method according to claim 1, characterized in that: The step "compare P2 with 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 obtained according to the change in helium concentration and the comparison result of P2 and PJ." also includes the determination step: If the comparison result is P2<PJ, and the helium content slowly decreases and then increases, the check piece on one side of the actuating chamber leaks.

4. A check valve air tightness detection method according to claim 1, characterized in that: The step "compare P3 with PF, if P3 = PF, and the helium content in the actuating chamber continues to decrease to a stable state, it is determined that the actuating chamber has no leakage, otherwise the location of the leakage point is obtained according to the change in helium concentration and the comparison result of P3 and PF." also includes the determination step: If the comparison result is P3<PJ, the helium content in the actuating chamber continues to decrease to a stable state, and the helium content in the check chamber remains stable, then leakage occurs in the side wall of the actuating chamber.

5. A check valve air tightness detection method according to claim 1, characterized in that: The step "compare P3 with PF, if P3 = PF, and the helium content in the actuating chamber continues to decrease to a stable state, it is determined that the actuating chamber has no leakage, otherwise the location of the leakage point is obtained according to the change in helium concentration and the comparison result of P3 and PF." also includes the determination step: If the comparison result is P3<PF, and the helium content in the actuating chamber continuously decreases to a stable state, then decreases again and remains stable again, the helium content in the check chamber decreases, and the check piece on one side of the check chamber leaks.

6. A check valve air tightness detection method according to claim 1, characterized in that: When it is determined that the check chamber and the actuating chamber have no leakage, moving the connecting ends of the mechanical pump and the molecular pump and the check valve to the ports of the actuating chamber and the check chamber; Repeat step " to simultaneously extract the gas in the actuating chamber and the check chamber through the mechanical pump, and at this time the negative pressure in the check chamber reaches P2; The helium in the actuating chamber is extracted by the molecular pump, and the negative pressure in the check chamber reaches P3; the following step further includes: Comparing P2 with PJ, if the comparison result is P2<PJ, it is determined that the check chamber port leaks; Compare P3 with PF. If the comparison result is P3<PF, it is determined that leakage occurs at the port of the actuating chamber.

7. A check valve air tightness detection method according to claim 1, characterized in that: When it is determined that the check chamber and the actuating chamber have no leakage, a sealing cover is provided, the check valve is arranged on the cover, helium is injected into the sealing cover, and a helium meter is connected, and step " is repeated to simultaneously extract the gas in the actuating chamber and the check chamber through the mechanical pump, and at this time the negative pressure in the check chamber reaches P2; The helium in the actuating chamber is extracted by the molecular pump, and the negative pressure in the check chamber reaches P3; the following step further includes: The helium concentration in the sealing cover is observed. If the helium concentration decreases, micropores exist in the side wall of the check valve.

8. A check valve air tightness detection method according to claim 1, characterized in that: Repeating the steps in claim 1 is used to prevent accidental errors in detection.

9. A check valve air tightness detection device, comprising a check valve air tightness detection method according to any one of claims 1 to 8, characterized in that: The detection device also includes: A check valve comprises a valve body and a check member movably connected to the valve body, wherein the check member is arranged in the valve body and separates the valve body into an actuating chamber and a check chamber; A pumping assembly, comprising a mechanical pump and a molecular pump, wherein the mechanical pump is connected to the actuating chamber and the check chamber respectively, and the molecular pump is connected to the actuating chamber; A detection component, connected to the suction pipe, for detecting the helium concentration in the check valve; Wherein, the suction assembly further comprises a suction tube movably connected to the valve body, and the suction tube abuts against inner walls of the check chamber and the actuating chamber respectively, so as to detect leakage conditions in different areas of the valve body.

10. A check valve air tightness detection method according to claim 1, characterized in that: The suction pipe comprises an integrally arranged main body and an elastic layer, one end of the elastic layer is arranged at the end of the main body, and the other end is arranged outwardly inclined, the inner surfaces of the check cavity and the actuating cavity both have a step surface, and when the suction pipe extends into the valve body, the elastic layer abuts against the step surface; The detection device also includes a sealing cover which is covered on the check valve, and the sealing cover is connected to the detection component and is used to isolate the external air.

Images