Multifunctional sealing performance detection device of diaphragm capsule for end face sealing and vacuum helium mass spectrum leakage detection method, positive pressure helium mass spectrum leakage detection method and air tightness detection method of multifunctional sealing performance detection device

Abstract

The invention relates to a sealing performance detection device of a tubular elastic sensitive element and a detection method thereof, in particular to a multifunctional sealing performance detection device of a diaphragm capsule for end face sealing and a vacuum helium mass spectrum leakage detection method, a positive pressure helium mass spectrum leakage detection method and an air tightness detection method of the multifunctional sealing performance detection device. The objective of the invention is to solve the problems of narrow detection range, high cost, tedious operation or influence on the size and precision of a diaphragm capsule in a conventional diaphragm capsule sealing performance detection method for end face sealing. The device comprises a shell, a gas detection core coaxially arranged in one end of the shell, a positioning core shaft coaxially arranged at the other end of the shell, a filler neck of which the output end is arranged on the side wall of the shell and is communicated with the interior of the shell, and a helium detection adapter connected with the input end of the filler neck, a step-shaped test cavity is arranged on the inner side wall of the shell; the gas detection core comprises a head part and a tail part which are coaxially connected with each other; the two ends of the positioning mandrel are both matched with the positioning holes, and a rigid fixing clamping sleeve is arranged between the two first sealing pieces and located on the outer side of the diaphragm capsule for end face sealing.

Description

Technical Field

[0001] The present invention relates to a sealing detection device and a detection method of a tubular elastic sensitive element, and in particular to a multifunctional sealing detection device of a membrane box for end face sealing and a vacuum helium mass spectrometer leak detection, positive pressure helium mass spectrometer leak detection and airtightness inspection method thereof. Background Art

[0002] The end face seal device is a device used for dynamic sealing between a rotating shaft and a base body. Under the action of fluid pressure, elastic force of a compensation mechanism and cooperation of auxiliary seals, a pair of friction pairs are kept in contact and slide relative to each other to form a friction pair sealing surface, thereby preventing fluid leakage. The end face sealing method can be divided into bellows-type end face seals and spring-type end face seals according to the type of elastic element. The spring-type end face seal is limited by its own structural characteristics and cannot withstand high temperatures, and can only be used in normal temperature conditions; the bellows-type end face seal has good high temperature resistance and tracking performance, and can buffer the vibration of the shaft. The bellows in the bellows-type end face seal can not only seal the medium, but also play a role of elastic compensation, and can be applied to low or high temperature conditions.

[0003] Based on the above characteristics, bellows-type end face seals are widely used in the end face seals of turbine pumps in aerospace liquid rocket engines. The bellows used in bellows-type end face seals generally include hydraulically expanded bellows and end face seal diaphragms in the form of welding. The structural diagram of the end face seal diaphragm is shown in the figure below. Figure 1 As shown, it is a tubular element formed by alternately welding multiple pairs of corrugated diaphragms 11 along their inner and outer edges using precision welding technology. It has the characteristics of precision, thin wall, good elasticity and high compression rate. It usually adopts argon arc welding, micro-beam plasma and other welding methods. The total number of welds is as many as more than ten, including inner welds 12 and outer welds 13.

[0004] The working environment of aerospace liquid rocket engines is usually harsh, with the main characteristics of high speed (maximum speed can reach more than 40,000 rpm), harsh ambient temperature (minimum temperature can reach -183°C, maximum temperature can reach more than 650°C), high medium pressure (medium pressure is about 0.5-5.0MPa) and large dynamic load. Due to the harsh working environment, there are very high requirements for the production quality and reliability of the diaphragm box. Once the diaphragm box fails during the operation of the engine, it will cause leakage of the sealing medium and abnormal operation of the engine at the least, or even cause engine accidents, resulting in huge losses.

[0005] At present, most of the diaphragm box manufacturers use helium mass spectrometry leak detection to check the sealing after the diaphragm box is welded; or after the diaphragm box is welded with the machined parts at both ends, a positive pressure helium mass spectrometry leak detection or air tightness inspection is performed under a specified pressure. Although the existing methods can meet the production and delivery requirements of the products, they have the following shortcomings:

[0006] 1) At present, after the diaphragm box is welded, most of them only use the vacuum helium mass spectrometry leak detection method to check the sealing, that is, use rubber rings, rubber pads, etc. to seal the diaphragms on the upper and lower ends of the diaphragm box, then evacuate the inner cavity of the diaphragm box, and spray helium from the outside for inspection. The above inspection method can only check the sealing of the diaphragm box weld under the pressure difference of 1 atmosphere (about 0.1MPa); while the actual working pressure of the diaphragm box can usually reach 1.5MPa~5.0MPa, or even higher. The helium inspection method obviously cannot fully cover the working conditions of the diaphragm box and has a narrow detection range.

[0007] 2) Since the diaphragm box is an elastic element that is not easy to seal, and the diaphragm material is thin and easy to be damaged, if you want to perform positive pressure helium mass spectrometry leak detection or pressurized air tightness inspection, the current process is basically carried out according to the following procedures:

[0008] a. Perform stress relief heat treatment or aging strengthening treatment on the membrane box;

[0009] b. Combine and weld the diaphragm box with the parts to be welded at both ends (most of the parts currently welded to the two ends of the diaphragm box contain non-metallic materials and the diaphragm box is a different metal material, which is not suitable for the process of welding first and then heat treatment);

[0010] c. After welding, seal the parts at both ends and conduct positive pressure helium mass spectrometry leak detection or air tightness inspection under the specified pressure.

[0011] The disadvantage of this method is that if leakage is found in the diaphragm box weld, it cannot be remedied by rework welding (rework welding is not allowed after the diaphragm box has been heat treated). At the same time, it also causes waste of welded parts at both ends, increasing production costs.

[0012] 3) The existing diaphragm box air tightness inspection tooling and helium mass spectrometer leak detection tooling do not have a diaphragm box height limit function. The diaphragm box is prone to tensile or compressive deformation when subjected to pressure or vacuum during the inspection process, affecting the free height size of the diaphragm box and the accuracy of the parallelism of the two end faces.

[0013] 4) Currently, three sets of devices are required to perform vacuum helium mass spectrometry leak detection, positive pressure helium mass spectrometry leak detection and air tightness inspection of the membrane box respectively, which has poor integration and high cost; the operation is cumbersome, and the membrane box is easily damaged due to repeated disassembly and assembly. Summary of the invention

[0014] The purpose of the present invention is to solve the problems of existing end face sealing membrane box sealing detection methods such as narrow detection range, high cost, cumbersome operation or affecting the size and accuracy of the membrane box itself, and to provide a multifunctional sealing detection device for an end face sealing membrane box and its vacuum helium mass spectrometry leak detection, positive pressure helium mass spectrometry leak detection, and airtightness inspection methods.

[0015] To achieve the above purpose, the technical solution provided by the present invention is:

[0016] A multifunctional sealing detection device for an end face sealing diaphragm box is used for vacuum helium mass spectrometry leak detection, positive pressure helium mass spectrometry leak detection or air tightness inspection of the end face sealing diaphragm box. The end face sealing diaphragm box is a bellows, comprising a plurality of stacked wave-shaped annular diaphragms, the inner sides of the plurality of diaphragms are welded in pairs to form an inner weld, and the two diaphragms corresponding to each inner weld are respectively welded to the adjacent diaphragms of the adjacent inner weld to form an outer weld; the special feature of the device is that:

[0017] It comprises a shell, a gas detection core coaxially arranged in one end of the shell, a positioning core shaft coaxially arranged in the other end of the shell, a nozzle whose output end is arranged on the side wall of the shell and communicated with the inside of the shell, and a helium detection adapter connected to the input end of the nozzle;

[0018] The inner side wall of the shell is configured as a stepped test cavity, and a positioning hole is provided in the middle of the end surface of the small diameter end;

[0019] The gas inspection core comprises a head and a tail connected coaxially to each other, the head is a stepped cylinder with a side surface, the step of the stepped cylinder matches the step surface of the test cavity, the tail is a first cylinder, one end of the tail is connected to the large end of the head, the small end of the head is provided with a circular groove, the center of the circular groove is axially provided with a first through hole communicating with the other end surface of the tail;

[0020] Both ends of the positioning core shaft are adapted to the positioning hole, a fourth sealing member is provided on the side wall of one end thereof, and a raised ring is provided on the positioning core shaft near the end;

[0021] A second sealing member is provided between the inner side surface of the small end of the test cavity and the outer side surface of the small end of the stepped column, and a fastener and a third sealing member for sealing between the fastener and the end of the first through hole are provided at one end of the first through hole located at the tail of the gas inspection core;

[0022] The output end of the take-over nozzle is arranged on the side of the small end of the test cavity, and the input end of the take-over nozzle is connected to a helium mass spectrometer leak detector through a helium detection adapter, or the input end of the take-over nozzle is connected to a helium gas cylinder;

[0023] A membrane box for end face sealing is placed between the small end of the test cavity and the end face of the small end of the stepped column, and first sealing members are arranged opposite to each other at the bottom of the small end of the test cavity and the end face of the small end of the air inspection core, for sealing the membrane box for end face sealing, and a rigid fixing sleeve for supporting the membrane box for end face sealing is arranged between the two first sealing members and located outside the membrane box for end face sealing.

[0024] Furthermore, the rigid fixing sleeve is a circular ring composed of two semicircular rings, and a plurality of vent holes are evenly distributed circumferentially on the circular ring.

[0025] Furthermore, the connection between the shell and the gas detection core, and between the helium detection adapter and the take-over nozzle are all threaded connections; a fifth sealing member is provided between the input end of the take-over nozzle and the output end of the helium detection adapter.

[0026] Furthermore, the first seal, the second seal, the third seal and the fourth seal are all rubber rings; the fifth seal is a rubber gasket; the rigid fixing sleeve is made of copper; the positioning core shaft is made of fluoroplastic; and the fastener is a hexagon socket screw.

[0027] Furthermore, the diameter of the positioning hole is the inner hole diameter of the membrane box for end face sealing + (0.03-0.05) mm.

[0028] Furthermore, the unilateral fitting clearance between the end of the positioning core shaft without the fourth seal and the positioning hole is 0.02-0.04mm; the unilateral fitting clearance between the outer side surface of the end of the positioning core shaft with the fourth seal and the inner side surface of the positioning hole is 0.15-0.20mm; the fitting clearance between the inner side surface of the shell and the outer side surface of the gas inspection core is 0.15-0.20mm; when the end of the positioning core shaft with the fourth seal is installed in the shell, the axial compression of the fourth seal is 8%-10%; when the gas inspection core is installed in the shell, the axial compression of the second seal is 8%-10%.

[0029] Furthermore, the number of the ventilation holes is 6 to 8, and the diameter of each ventilation hole is 3 to 5 mm.

[0030] At the same time, the present invention also provides a vacuum helium mass spectrometry leak detection method of the multifunctional sealing detection device of the end face sealing membrane box, which is special in that it includes the following steps:

[0031] Step 1, prepare a helium gas cylinder, a helium mass spectrometer leak detector and a membrane box for end face sealing to be tested; define the area between the rigid fixed ferrule and the inner end face of the small end of the test cavity as the first inner cavity, and define the communicating area formed by the inner cavity of the circular groove, the inner cavity of the positioning hole and the inner cavity of the membrane box for end face sealing as the second inner cavity;

[0032] Step 2, install the end of the positioning mandrel without the fourth sealing member in the positioning hole, and then install the end face sealing membrane box to be tested into a preset position according to the positioning of the end of the positioning mandrel, and set the preset leakage amount L1 of the weld;

[0033] Step 3: Remove the positioning mandrel, and then connect the helium bottle to the outer end of the positioning hole;

[0034] Step 4, connecting the input end of the helium detection adapter to the leak detection port of the helium mass spectrometer leak detector, and turning on the helium mass spectrometer leak detector to evacuate the first inner cavity;

[0035] Step 5, open the helium cylinder to spray helium into the second inner cavity, and use the helium mass spectrometer leak detector to detect the helium leakage per unit time L2 of the first inner cavity, and compare L2 with L1 set in step 2. If L2≤L1, the vacuum helium mass spectrometer leak detection of the membrane box for end face sealing under test is qualified; if L2>L1, the vacuum helium mass spectrometer leak detection of the membrane box for end face sealing under test is unqualified.

[0036] In addition, the present invention also provides a positive pressure helium mass spectrometer leak detection method for the multifunctional sealing detection device of the end face sealing membrane box, which is special in that it includes the following steps:

[0037] Step 1, prepare a helium gas cylinder, a helium mass spectrometer leak detector and a membrane box for end face sealing to be detected; define the area between the rigid fixed ferrule and the inner side of the small end of the first cylinder as the first inner cavity, and define the communicating area formed by the inner cavity of the circular groove, the inner cavity of the positioning hole and the inner cavity of the membrane box for end face sealing as the second inner cavity;

[0038] Step 2, install the end of the positioning mandrel without the fourth sealing member in the positioning hole, and then install the end face sealing membrane box to be tested into a preset position according to the positioning of the end of the positioning mandrel, and set the preset leakage amount L3 of the weld;

[0039] Step 3, remove the positioning mandrel, and insert the end of the positioning mandrel with the fourth seal into the positioning hole;

[0040] Step 4, remove the helium detection adapter, the fastener and the third sealing member, connect the input end of the nozzle to the output end of the helium cylinder, connect the outer end of the first through hole on the gas detection core to the leak detection port of the helium mass spectrometer leak detector, and then start the helium mass spectrometer leak detector to evacuate the second inner cavity;

[0041] Step 5, open the helium cylinder and spray helium into the first inner cavity. At the same time, the helium mass spectrometer leak detector detects the helium leakage per unit time L4 of the second inner cavity, and compares L4 with L3 set in step 2. If L4≤L3, the positive pressure helium mass spectrometer leak detection of the membrane box for end face sealing is qualified; if L4>L3, the positive pressure helium mass spectrometer leak detection of the membrane box for end face sealing is unqualified.

[0042] In addition, the present invention also provides an airtightness inspection method of the multifunctional airtightness inspection device of the end face sealing membrane box, which is special in that it comprises the following steps:

[0043] Step 1, prepare the end face sealing membrane box and the compressed air bottle to be tested; define the area between the rigid fixed ferrule and the inner side of the small end of the first cylinder as the first inner cavity, and define the connecting area formed by the inner cavity of the circular groove, the inner cavity of the positioning hole and the inner cavity of the end face sealing membrane box as the second inner cavity;

[0044] Step 2: Install the end of the positioning mandrel without the fourth seal into the positioning hole, and then install the end face seal membrane box to be tested into the preset position according to the positioning of the positioning mandrel by one end.

[0045] Step 3: Remove the positioning mandrel and the helium detection adapter, and make the outer end opening of the positioning hole face vertically upward;

[0046] Step 4, connect the input end of the nozzle to the output end of the compressed air bottle, open the compressed air bottle, spray compressed air into the first inner cavity, and when the pressure of the sprayed compressed air is stable, inject a preset amount of leakage-indicating liquid from the outer end opening of the positioning hole into the second inner cavity; wherein the leakage-indicating liquid is pure water or anhydrous ethanol, and the injection amount of the leakage-indicating liquid is 2mm to 5mm higher than the inner weld of the top of the membrane box for end face sealing;

[0047] Step 5, observe whether there are bubbles in the leakage-indicating liquid. If there are no bubbles, the air-tightness test of the membrane box for sealing the inspected end face is qualified; otherwise, the air-tightness test is unqualified.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. The present invention provides a multifunctional sealing detection device for an end face sealing membrane box, which includes three detection modes: vacuum helium mass spectrometry leak detection, positive pressure helium mass spectrometry leak detection and airtightness inspection of the end face sealing membrane box, which has strong integration, can reduce preparation procedures and reduce production energy consumption;

[0050] 2. The multifunctional sealing detection device for the membrane box for end face sealing provided by the present invention does not need to be repeatedly assembled when switching the detection mode, but only needs to simply replace several components, which is fast and convenient to operate; at the same time, the assembly positioning accuracy and the consistency of the assembly position can be guaranteed;

[0051] 3. The present invention provides a multifunctional sealing detection device for a membrane box for end face sealing. By using a rigid fixed sleeve composed of two semicircular rings, the membrane box is supported to make it a rigid part. After clamping and sealing, the sealing performance of the membrane box under higher pressure can be detected. At the same time, the membrane box can be effectively prevented from being over-stretched after air inspection or positive pressure leak detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a structural schematic diagram of an existing membrane box for end face sealing;

[0053] Figure 2 It is a structural schematic diagram of an embodiment of a multifunctional sealing detection device for an end face sealing membrane box of the present invention;

[0054] Figure 3It is a structural schematic diagram of an embodiment of a multifunctional sealing detection device of a membrane box for end face sealing of the present invention when performing vacuum helium mass spectrometry leak detection;

[0055] Figure 4 It is a structural schematic diagram of an embodiment of a multifunctional sealing detection device of a membrane box for end face sealing of the present invention when performing positive pressure helium mass spectrometry leak detection;

[0056] Figure 5 It is a structural schematic diagram of an embodiment of a multifunctional sealing detection device for an end face sealing membrane box of the present invention when performing airtightness inspection;

[0057] Description of reference numerals:

[0058] 11. Diaphragm; 12. Inner weld; 13. Outer weld; 21. Shell; 22. Gas inspection core; 2201. First through hole; 2202. Circular groove; 23. Positioning mandrel; 2301. Raised ring; 24. Rigid fixing ferrule; 25. Take-over nozzle; 26. Helium inspection adapter; 27. Fastener; 28. First seal; 29. ​​Second seal; 210. Third seal; 211. Fourth seal; 212. Fifth seal; J. First inner cavity; K. Second inner cavity. DETAILED DESCRIPTION

[0059] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0060] A multifunctional sealing detection device for a membrane box for end face sealing, see Figure 2 , used for vacuum helium mass spectrometry leak detection, positive pressure helium mass spectrometry leak detection or air tightness inspection of the membrane box for end face sealing, the membrane box for end face sealing is a bellows, including a plurality of wave-shaped annular membranes 11 stacked, the inner sides of the plurality of membranes 11 are welded in pairs to form an inner weld 12, and the two membranes 11 corresponding to each inner weld 12 are respectively welded to the adjacent membranes 11 of the adjacent inner weld 12 to form an outer weld 13;

[0061] It includes a housing 21, a gas detection core 22 coaxially arranged in one end of the housing 21, a positioning core shaft 23 coaxially arranged at the other end of the housing 21, a nozzle 25 whose output end is arranged on the side wall of the housing 21 and communicated with the interior of the housing 21, and a helium detection adapter 26 connected to the input end of the nozzle 25;

[0062] The inner side wall of the housing 21 is configured as a stepped test cavity, and a positioning hole 201 is provided in the middle of the end surface of the small diameter end thereof;

[0063] The gas inspection core 22 includes a head and a tail connected coaxially to each other, the head is a stepped cylinder with a side surface, the step of the stepped cylinder matches the step surface of the test cavity, the tail is a first cylinder, one end of the tail is connected to the large end of the head, the small end of the head is provided with a circular groove 2202, and the center of the circular groove 2202 is axially provided with a first through hole 2201 communicating with the other end face of the tail;

[0064] Both ends of the positioning core shaft 23 are adapted to the positioning hole 201, a fourth sealing member 211 is provided on the side wall of one end thereof, and a raised ring 2301 is provided on the positioning core shaft 23 near the end thereof;

[0065] A second sealing member 29 is provided between the inner side surface of the small end of the test cavity and the outer side surface of the small end of the stepped column, and a fastener 27 and a third sealing member 210 for sealing between the fastener 27 and the end of the first through hole 2201 are provided at one end of the first through hole 2201 located at the tail of the gas inspection core 22;

[0066] The output end of the take-over nozzle 25 is arranged on the side of the small end of the test cavity, and the input end of the take-over nozzle 25 is connected to the helium mass spectrometer leak detector through the helium detection adapter 26, or the input end of the take-over nozzle 25 is connected to the helium gas cylinder;

[0067] A membrane box for end face sealing is placed between the small end of the test cavity and the end face of the small end of the stepped column. A first sealing member 28 is relatively arranged at the bottom of the small end of the test cavity and on the end face of the small end of the air inspection core 22 for sealing the membrane box for end face sealing. A rigid fixed sleeve 24 for supporting the membrane box for end face sealing is arranged between the two first sealing members 28 and located outside the membrane box for end face sealing. The rigid fixed sleeve 24 is located outside the membrane box for end face sealing.

[0068] The rigid fixing sleeve 24 is used to support the membrane box for end face sealing, making it a rigid part. The rigid fixing sleeve 24 is made of copper. For easy installation, it includes a ring composed of two semicircular rings. There are 6 to 8 vents with a diameter of 3 to 5 mm evenly distributed on the ring in the circumferential direction, which is convenient for the entry and exit of helium, the leak detection gas. The diameter of the vent can be determined according to the height of the rigid fixing sleeve 24, generally 3 to 5 mm. The positioning mandrel 23 is made of fluoroplastics with high strength.

[0069] The connection between the housing 21 and the gas detection core 22 , and between the helium detection adapter 26 and the take-over nozzle 25 are all threaded connections; a fifth sealing member 212 is provided between the input end of the take-over nozzle 25 and the output end of the helium detection adapter 26 .

[0070] In this embodiment, the first seal 28, the second seal 29, the third seal 210, and the fourth seal 211 are all rubber rings; the fifth seal 212 is a rubber gasket; for ease of disassembly, the fastener 27 is a hexagon socket screw. During processing, the unilateral fitting clearance between the end of the positioning mandrel 23 not provided with the fourth seal 211 and the positioning hole 201 is 0.02 to 0.04 mm; the unilateral fitting clearance between the outer side surface of the end of the positioning mandrel 23 provided with the fourth seal 211 and the inner side surface of the positioning hole 201 is 0.15 to 0.20 mm; the fitting clearance between the inner side surface of the housing 21 and the outer side surface of the gas inspection core 22 is 0.15 to 0.20 mm;

[0071] When the positioning core shaft 23 with one end of the fourth seal 211 is installed in the housing 21, the axial compression of the fourth seal 211 is 8% to 10%; when the air inspection core 22 is installed in the housing 21, the axial compression of the second seal 29 is 8% to 10%.

[0072] At the same time, this embodiment also provides a vacuum helium mass spectrometer leak detection method for the multifunctional sealing detection device of the end face sealing membrane box, see Figure 3 , including the following steps:

[0073] Step 1, prepare a helium gas cylinder, a helium mass spectrometer leak detector and a membrane box for end face sealing to be tested; define the area between the rigid fixed ferrule 24 and the inner end face of the small end of the test cavity as the first inner cavity J, and define the connecting area formed by the inner cavity of the circular groove 2202, the inner cavity of the positioning hole 201 and the inner cavity of the membrane box for end face sealing as the second inner cavity K;

[0074] Step 2, install the end of the positioning core shaft 23 without the fourth sealing member 211 in the positioning hole 201, and then install the end face sealing membrane box to be tested into a preset position according to the positioning of the end of the positioning core shaft 23, and set the preset leakage amount L1 of the weld;

[0075] Step 3, remove the positioning mandrel 23, and then connect the helium cylinder to the outer end of the positioning hole 201;

[0076] Step 4, connect the input end of the helium detection adapter 26 to the leak detection port of the helium mass spectrometer leak detector, turn on the helium mass spectrometer leak detector to evacuate the first inner cavity J;

[0077] Step 5, open the helium cylinder to spray helium into the second inner cavity K, and use the helium mass spectrometer leak detector to detect the helium leakage per unit time L2 of the first inner cavity J, and compare L2 with L1 set in step 2. If L2≤L1, the vacuum helium mass spectrometer leak detection of the membrane box for end face sealing is qualified; if L2>L1, the vacuum helium mass spectrometer leak detection of the membrane box for end face sealing is unqualified.

[0078] Moreover, this embodiment also provides a positive pressure helium mass spectrometer leak detection method for the multifunctional sealing detection device of the end face sealing membrane box, see Figure 4 , including the following steps:

[0079] Step 1, prepare a helium gas cylinder, a helium mass spectrometer leak detector and a membrane box for end face sealing to be detected; define the area between the rigid fixed ferrule 24 and the inner side of the small end of the first cylinder as the first inner cavity J, and define the connecting area formed by the inner cavity of the circular groove 2202, the inner cavity of the positioning hole 201 and the inner cavity of the membrane box for end face sealing as the second inner cavity K;

[0080] Step 2, install the end of the positioning core shaft 23 without the fourth sealing member 211 in the positioning hole 201, and then install the end face sealing membrane box to be tested into a preset position according to the positioning of the end of the positioning core shaft 23, and set the preset leakage amount L3 of the weld;

[0081] Step 3, remove the positioning mandrel 23, and insert the end of the positioning mandrel 23 with the fourth sealing member 211 into the positioning hole 201;

[0082] Step 4, remove the helium detection adapter 26, the fastener 27 and the third sealing member 210, connect the input end of the nozzle 25 to the output end of the helium gas bottle, connect the outer end of the first through hole 2201 on the gas detection core 22 to the leak detection port of the helium mass spectrometer leak detector, and then start the helium mass spectrometer leak detector to evacuate the second inner cavity K;

[0083] Step 5, open the helium cylinder and spray helium into the first inner cavity J. At the same time, the helium mass spectrometer leak detector detects the helium leakage per unit time L4 of the second inner cavity K, and compares L4 with L3 set in step 2. If L4≤L3, the positive pressure helium mass spectrometer leak detection of the membrane box for end face sealing is qualified; if L4>L3, the positive pressure helium mass spectrometer leak detection of the membrane box for end face sealing is unqualified.

[0084] In addition, this embodiment also provides an airtightness inspection method for the multifunctional sealing inspection device of the end face sealing membrane box, see Figure 5 , including the following steps:

[0085] Step 1, prepare the end face sealing membrane box and compressed air bottle to be tested; define the area between the rigid fixed ferrule 24 and the inner side of the small end of the first cylinder as the first inner cavity J, and define the connecting area formed by the inner cavity of the circular groove 2202, the inner cavity of the positioning hole 201 and the inner cavity of the end face sealing membrane box as the second inner cavity K;

[0086] Step 2: Install the end of the positioning mandrel 23 without the fourth sealing member 211 in the positioning hole 201, and then install the end face sealing membrane box to be tested into a preset position according to the positioning of the end of the positioning mandrel 23.

[0087] Step 3, remove the positioning mandrel 23 and the helium detection adapter 26, and make the outer end opening of the positioning hole 201 vertically upward;

[0088] Step 4, connect the input end of the nozzle 25 to the output end of the compressed air bottle, open the compressed air bottle, spray compressed air into the first inner cavity J, and when the pressure of the sprayed compressed air is stable, inject a preset amount of leakage-indicating liquid from the outer end opening of the positioning hole 201 into the second inner cavity K; wherein the leakage-indicating liquid is pure water or anhydrous ethanol, and the injection amount of the leakage-indicating liquid is higher than the inner weld 12 at the top of the end face sealing membrane box, and the height is 2mm to 5mm higher;

[0089] Step 5, observe whether there are bubbles in the leakage-indicating liquid. If there are no bubbles, the air-tightness test of the membrane box for sealing the inspected end face is qualified; otherwise, the air-tightness test is unqualified.

[0090] The above three detection methods can be selected or performed in no particular order according to actual needs.

Claims

1. A multifunctional sealing detection device for an end face sealing diaphragm box, used for performing vacuum helium mass spectrometry leak detection, positive pressure helium mass spectrometry leak detection or air tightness inspection on the end face sealing diaphragm box, wherein the end face sealing diaphragm box is a bellows, comprising a plurality of wave-shaped annular diaphragms (11) stacked and arranged, wherein the inner sides of the plurality of diaphragms (11) are welded in pairs to form inner welds (12), and the two diaphragms (11) corresponding to each inner weld (12) are respectively welded to the adjacent diaphragms (11) of the adjacent inner weld (12) to form an outer weld (13); characterized in that: It comprises a housing (21), a gas detection core (22) coaxially arranged in one end of the housing (21), a positioning core shaft (23) coaxially arranged in the other end of the housing (21), a nozzle (25) whose output end is arranged on the side wall of the housing (21) and communicates with the interior of the housing (21), and a helium detection adapter (26) connected to the input end of the nozzle (25); The inner side wall of the housing (21) is arranged as a stepped test cavity, and a positioning hole (201) is arranged in the middle of the end surface of the small diameter end; The gas inspection core (22) comprises a head and a tail which are coaxially connected to each other, the head is a stepped column with a side surface, the step of the stepped column matches the step surface of the test cavity, the tail is a first cylinder, one end of the tail is connected to the large end of the head, the small end of the head is provided with a circular groove (2202), and the center of the circular groove (2202) is axially provided with a first through hole (2201) which is in communication with the other end surface of the tail; Both ends of the positioning core shaft (23) are adapted to the positioning hole (201), a fourth sealing member (211) is provided on the side wall of one end thereof, and a raised ring (2301) is provided on the positioning core shaft (23) near the end thereof; A second sealing member (29) is provided between the inner side surface of the small end of the test cavity and the outer side surface of the small end of the stepped column; a fastener (27) and a third sealing member (210) for sealing between the fastener (27) and the end of the first through hole (2201) are provided at one end of the first through hole (2201) located at the tail of the gas inspection core (22); The output end of the take-over nozzle (25) is arranged on the side of the small end of the test cavity, and the input end of the take-over nozzle (25) is connected to a helium mass spectrometer leak detector through a helium detection adapter (26), or the input end of the take-over nozzle (25) is connected to a helium gas cylinder; A membrane box for end face sealing is placed between the small end of the test cavity and the end face of the small end of the stepped column. A first sealing member (28) is arranged opposite to each other at the bottom of the small end of the test cavity and the end face of the small end of the gas inspection core (22) for sealing the membrane box for end face sealing. A rigid fixing sleeve (24) for supporting the membrane box for end face sealing is arranged between the two first sealing members (28) and located outside the membrane box for end face sealing.

2. The multifunctional sealing detection device for the membrane box for end face sealing according to claim 1, characterized in that: The rigid fixing sleeve (24) is a circular ring composed of two semicircular rings, and a plurality of vent holes are evenly distributed circumferentially on the circular ring.

3. The multifunctional sealing detection device for the membrane box for end face sealing according to claim 2, characterized in that: The connection between the housing (21) and the gas detection core (22), and between the helium detection adapter (26) and the nozzle (25) are all threaded connections; a fifth sealing member (212) is provided between the input end of the nozzle (25) and the output end of the helium detection adapter (26).

4. The multifunctional sealing detection device for the membrane box for end face sealing according to claim 3 is characterized in that: The first sealing member (28), the second sealing member (29), the third sealing member (210), and the fourth sealing member (211) are all rubber rings; the fifth sealing member (212) is a rubber gasket; the rigid fixing sleeve (24) is made of copper; the positioning core shaft (23) is made of fluoroplastic; and the fastener (27) is a hexagon socket screw.

5. The multifunctional sealing detection device for the membrane box for end face sealing according to claim 4, characterized in that: The diameter of the positioning hole (201) is the diameter of the inner hole of the membrane box for end face sealing + (0.03-0.05) mm.

6. The multifunctional sealing detection device for the membrane box for end face sealing according to claim 5, characterized in that: The unilateral fitting clearance between the end of the positioning core shaft (23) not provided with the fourth sealing member (211) and the positioning hole (201) is 0.02 to 0.04 mm; the unilateral fitting clearance between the outer side surface of the end of the positioning core shaft (23) provided with the fourth sealing member (211) and the inner side surface of the positioning hole (201) is 0.15 to 0.20 mm; the fitting clearance between the inner side surface of the housing (21) and the outer side surface of the gas inspection core (22) is 0.15 to 0.20 mm; When one end of the positioning core shaft (23) provided with the fourth sealing member (211) is installed in the housing (21), the axial compression amount of the fourth sealing member (211) is 8% to 10%; when the air inspection core (22) is installed in the housing (21), the axial compression amount of the second sealing member (29) is 8% to 10%.

7. The multifunctional sealing detection device for the membrane box for end face sealing according to claim 6, characterized in that: The number of the vent holes is 6 to 8, and the diameter of each vent hole is 3 to 5 mm.

8. A vacuum helium mass spectrometry leak detection method for the multifunctional sealing detection device of the end face sealing membrane box according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1, prepare a helium gas cylinder, a helium mass spectrometer leak detector and a membrane box for end face sealing to be tested; define the area between the rigid fixed ferrule (24) and the inner end face of the small end of the test cavity as the first inner cavity (J), and define the communicating area formed by the inner cavity of the circular groove (2202), the inner cavity of the positioning hole (201) and the inner cavity of the membrane box for end face sealing as the second inner cavity (K); Step 2, install the end of the positioning core shaft (23) without the fourth sealing member (211) in the positioning hole (201), and then install the membrane box for the end face seal to be tested into a preset position according to the positioning of the end of the positioning core shaft (23), and set the preset leakage amount L1 of the weld; Step 3, remove the positioning mandrel (23), and then connect the helium bottle to the outer end of the positioning hole (201); Step 4, connecting the input end of the helium detection adapter (26) to the leak detection port of the helium mass spectrometer leak detector, and turning on the helium mass spectrometer leak detector to evacuate the first inner cavity (J); Step 5, open the helium cylinder to spray helium into the second inner cavity (K), and use the helium mass spectrometer leak detector to detect the helium leakage per unit time L2 of the first inner cavity (J), and compare L2 with L1 set in step 2. If L2≤L1, the vacuum helium mass spectrometer leak detection of the membrane box for end face sealing is qualified; if L2>L1, the vacuum helium mass spectrometer leak detection of the membrane box for end face sealing is unqualified.

9. A positive pressure helium mass spectrometry leak detection method for the multifunctional sealing detection device of the end face sealing membrane box according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1, prepare a helium gas cylinder, a helium mass spectrometer leak detector and a membrane box for end face sealing to be detected; define the area between the rigid fixed ferrule (24) and the inner side surface of the small end of the first cylinder as the first inner cavity (J), and define the communicating area formed by the inner cavity of the circular groove (2202), the inner cavity of the positioning hole (201) and the inner cavity of the membrane box for end face sealing as the second inner cavity (K); Step 2, install the end of the positioning core shaft (23) without the fourth sealing member (211) in the positioning hole (201), and then install the membrane box for the end face seal to be tested into a preset position according to the positioning of the end of the positioning core shaft (23), and set the preset leakage amount L3 of the weld; Step 3, remove the positioning mandrel (23), and insert the end of the positioning mandrel (23) with the fourth sealing member (211) into the positioning hole (201); Step 4, remove the helium detection adapter (26), the fastener (27) and the third sealing member (210), connect the input end of the nozzle (25) to the output end of the helium gas bottle, connect the outer end of the first through hole (2201) on the gas detection core (22) to the leak detection port of the helium mass spectrometer leak detector, and then start the helium mass spectrometer leak detector to evacuate the second inner cavity (K); Step 5, open the helium cylinder and spray helium into the first inner cavity (J). At the same time, the helium mass spectrometer leak detector detects the helium leakage per unit time L4 of the second inner cavity (K), and compares L4 with L3 set in step 2. If L4≤L3, the positive pressure helium mass spectrometer leak test of the membrane box for end face sealing is qualified; if L4>L3, the positive pressure helium mass spectrometer leak test of the membrane box for end face sealing is unqualified.

10. A method for checking air tightness of a multifunctional sealing detection device for an end face sealing membrane box according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1, prepare the end face sealing membrane box and the compressed air bottle to be tested; define the area between the rigid fixing sleeve (24) and the inner side surface of the small end of the first cylinder as the first inner cavity (J), and define the connecting area formed by the inner cavity of the circular groove (2202), the inner cavity of the positioning hole (201) and the inner cavity of the end face sealing membrane box as the second inner cavity (K); Step 2: Install the end of the positioning core shaft (23) without the fourth sealing member (211) in the positioning hole (201), and then install the end face sealing membrane box to be tested into a preset position according to the positioning of the end of the positioning core shaft (23). Step 3, remove the positioning mandrel (23) and the helium detection adapter (26), and make the outer end opening of the positioning hole (201) vertically upward; Step 4, connect the input end of the nozzle (25) to the output end of the compressed air bottle, open the compressed air bottle, spray compressed air into the first inner cavity (J), and when the pressure of the sprayed compressed air is stable, inject a preset amount of leakage-indicating liquid from the outer end opening of the positioning hole (201) into the second inner cavity (K); wherein the leakage-indicating liquid is pure water or anhydrous ethanol, and the injection amount of the leakage-indicating liquid is 2 mm to 5 mm higher than the inner weld (12) at the top of the end face sealing membrane box; Step 5, observe whether there are bubbles in the leakage-indicating liquid. If there are no bubbles, the air-tightness test of the membrane box for sealing the inspected end face is qualified; otherwise, the air-tightness test is unqualified.

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