Sealing gasket leakage rate testing device

Abstract

A sealing gasket leakage rate testing device disclosed by the present invention comprises a compression column, a column table and a heating box, the first end of the compression column is provided with a first sleeve, the compression column is internally provided with a leakage detection medium injection channel, and a leakage detection medium injection port is formed in the first end face of the compression column; a testing area for placing a sealing gasket to be detected is arranged between the first end face of the pressing column and the second end face of the column table, a first side gap is formed between the inner wall of the first sleeve and the side wall of the column table, one end of the first sleeve is connected with a second sleeve in a heat insulation mode, and a second side gap is formed between the inner wall of the second sleeve and the side wall of the column table. The first backlash and the second backlash form a leak detection cavity which is connected with a leak detector, the section, away from the second end face, of the column table is a cooling section internally provided with a cooling channel, a sealing ring is arranged between the second sleeve and the cooling section to seal the leak detection cavity, the test area is located in the heating box, and the end, connected with the second sleeve, of the first sleeve extends out of the heating box. Influence of high temperature on sealing of the leak detection cavity can be avoided, and test accuracy is guaranteed.

Description

Technical Field

[0001] This invention relates to a device for testing the leakage rate of sealing gaskets, belonging to the technical field of sealing performance testing devices. Background Technology

[0002] Gasket leakage rate is a core indicator for evaluating the reliability of sealing systems, especially under high-temperature conditions, where the sealing structure of the testing device directly determines the accuracy of the test. Currently commonly used testing device structures, such as those disclosed in Chinese Patent Publication No. CN 101666700A, place the gasket between the upper and lower flanges, with the outer side of the gasket forming a leak detection chamber. A sealing ring is placed between the upper and lower flanges to seal the leak detection chamber. However, when performing high-temperature tests (900℃), these devices lack targeted temperature control and heat protection. The sealing ring is prone to thermal deformation and failure, and the device itself is susceptible to damage from accumulated high temperatures, thus affecting the stability and accuracy of the test. Summary of the Invention

[0003] To address the shortcomings of the existing technology, this invention provides a gasket leakage rate testing device, which solves the problem that the sealing ring is prone to deformation and failure under high-temperature operating conditions, thus affecting the accuracy of the test.

[0004] The technical solution of this invention is as follows: A gasket leakage rate testing device includes a pressure column, a column base, and a heating chamber. A first sleeve is provided at the first end of the pressure column. A leak detection medium injection channel is provided inside the pressure column, forming a leak detection medium injection port on the first end face of the pressure column. A test area for placing a gasket to be tested is located between the first end face of the pressure column and the second end face of the column base. A first side gap is provided between the inner wall of the first sleeve and the side wall of the column base. A second sleeve is thermally insulated at one end of the first sleeve. A second side gap is provided between the inner wall of the second sleeve and the side wall of the column base. The first side gap and the second side gap constitute a leak detection chamber. The leak detection chamber is connected to a leak detector. A section of the column base away from the second end face is a cooling section with an internal cooling channel. A sealing ring is provided between the second sleeve and the cooling section to seal the leak detection chamber. The test area is located inside the heating chamber. One end of the first sleeve connected to the second sleeve extends out from the heating chamber.

[0005] Furthermore, the second sleeve is provided with a leak detection connection channel, which is connected to the leak detection chamber. The outlet of the leak detection connection channel is connected to the leak detector, and the connection point between the leak detection connection channel and the leak detection chamber is located in the cooling section.

[0006] This solution utilizes a cooling section to cool the leaking gas as it passes through, reducing the impact of high temperatures on the leak detector.

[0007] Furthermore, to facilitate the placement of the leak-proof gasket to be tested, the first sleeve is detachably connected to the first end face of the pressure column.

[0008] Furthermore, a flexible graphite composite gasket with a built-in alloy skeleton is provided between the first sleeve and the first end face of the pressure column.

[0009] Furthermore, the side wall of the column is provided with a sealing groove, and the sealing ring is engaged in the sealing groove. The end of the second sleeve away from the first sleeve is provided with an inner flange. During the leakage rate test, the sealing ring is in close contact with the end face of the inner flange.

[0010] Furthermore, a first temperature sensor is provided near the first end face of the pressure column. The first temperature sensor is electrically connected to the controller, which is used to control the heating power of the heating box.

[0011] Furthermore, a second temperature sensor is provided on the second sleeve near the sealing ring. The second temperature sensor is electrically connected to a display device, which is used to display the temperature measured by the second temperature sensor.

[0012] Furthermore, the heating box encloses the pressure column, the first sleeve, and a portion of the column base.

[0013] Furthermore, the heating box includes an outer metal shell, an intermediate insulation layer, and an inner heating wire layer.

[0014] Compared with the prior art, the advantages of the technical solution provided by the present invention are as follows: This invention uses a heating chamber to heat the test area to meet the temperature requirements of the test conditions. The sealing ring of the leak detection chamber is placed between the second sleeve and the cooling section of the column. Through the heat insulation connection between the second sleeve and the first sleeve, and the cooling of the column, the sealing ring is prevented from directly bearing the high temperature, the heat conduction is slowed down and weakened, the service life of the sealing ring is improved, and the test stability under high temperature conditions is guaranteed. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the sealing gasket leakage rate testing device in an embodiment.

[0016] Figure 2 This is a three-dimensional structural diagram of the pressure column, first sleeve, second sleeve, and column platform in the sealing gasket leakage rate testing device of the embodiment.

[0017] Figure 3 The first schematic diagram shows the assembly process of the sealing gasket leakage rate testing device during testing, as described in this embodiment.

[0018] Figure 4This is a second schematic diagram showing the assembly process of the gasket leakage rate testing device during testing, as described in this embodiment. Detailed Implementation

[0019] The present invention will be further described below with reference to embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. After reading this description, any modifications of this description in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0020] Please combine Figure 1 and Figure 2 As shown in the figure, the gasket leakage rate testing device involved in this embodiment of the invention mainly includes a pressure column 1, a column platform 2, and a heating chamber 3. The pressure column 1 and the column platform 2 are two relatively movable components used to place the gasket 4 to be tested for leakage and to apply pressure to the gasket 4. In this embodiment, the pressure column 1 is located above, and the column platform 2 is located below, with the two arranged opposite each other. The lower end of the pressure column 1 is the first end, and the top end of the column platform 2 is the second end. The area between the first end face 101 (lower end face) of the pressure column 1 and the second end face 201 (top face) of the column platform 2 is the test area for placing the gasket 4 to be tested for leakage.

[0021] The pressure column 1 is controlled by a screw drive to move up and down. After the pressure column 1 moves upward, the leak-proof gasket 4 to be tested can be placed on the second end face 201 of the column 2. Then, the pressure column 1 is controlled to move downward so that its first end face 101 is in close contact with the leak-proof gasket 4. The movement of the pressure column 1 is used to determine the axial position for loading the leak-proof gasket 4 and also facilitates the testing operation. The column 2 is rigidly connected to the base 6 by bolts. The universal testing machine directly drives the base 6 to apply the load, and loads the leak-proof gasket 4 according to the preset computer program.

[0022] Both the pressure column 1 and the column base 2 are made of 310S austenitic stainless steel. This material has a temperature resistance limit of up to 1100℃, which fully covers the device's maximum operating condition requirement of 900℃. It also has excellent creep resistance at high temperatures and strong surface oxidation resistance, which can prevent the high-temperature oxide layer from affecting the fit and sealing performance with the leak-proof gasket 4 to be tested.

[0023] A leak detection medium injection channel 102 is provided inside the pressure column 1. The leak detection medium injection channel 102 forms an inlet on one side of the pressure column 1. This inlet is connected to the filling gas cylinder 7 through a vent valve 5 and a pipeline. The filling gas cylinder 7 is filled with a working medium for leak detection, which is generally helium. The other end of the leak detection medium injection channel 102 forms a leak detection medium injection port 103 in the center of the first end face 101 of the pressure column 1.

[0024] The first end face 101 of the pressure column 1 is also provided with a sleeve structure called the first sleeve 8, which is also made of 310S austenitic stainless steel. In some embodiments, the first sleeve 8 and the pressure column 1 are an integral structure and cannot be disassembled. During testing, the first sleeve 8 needs to be moved along its entire axial length relative to the column base 2 to expose the second end face 201 of the column base 2, resulting in a long travel distance. To improve convenience, this embodiment sets the first sleeve 8 and the pressure column 1 as a detachable connection. The first end face 101 of the pressure column 1 forms a connecting flange, and the top flange face of the first sleeve 8 is connected to the connecting flange by bolts. Specifically, a circular cavity is provided on the top flange face of the first sleeve 8 to place the first sealing gasket 10. The first sealing gasket 10 is a flexible graphite composite gasket with a built-in nickel-based alloy skeleton. It has a temperature resistance limit of up to 900℃, is suitable for high-temperature working environments, and has a high compression rebound rate. Under the action of the device bolt pre-tightening force, it can fully fill the micro-defects on the flange face. Its built-in nickel-based alloy skeleton has a thermal expansion coefficient close to that of the pressure column 1 and the first sleeve 8, so the gasket will not be unevenly compressed due to the expansion difference at high temperatures.

[0025] The first sleeve 8 is fitted onto the column base 2, and a first side gap 12 is formed between the inner wall of the first sleeve 8 and the side wall of the column base 2. A second sleeve 9, also made of 310S austenitic stainless steel, is connected below the first sleeve 8. To reduce heat conduction from the first sleeve 8 to the second sleeve 9, a heat-insulating sealing gasket 11 is placed between the lower flange face of the first sleeve 8 and the upper flange face of the second sleeve 9. The second sleeve 9 is also fitted onto the column base 2, and a second side gap 13 is formed between the inner wall of the second sleeve 9 and the side wall of the column base 2. The first side gap 12 and the second side gap 13 constitute a leak detection chamber. A leak detection connection channel 901 is opened on the side wall of the second sleeve 9. One end of the leak detection connection channel 901 communicates with the leak detection chamber, and the other end of the leak detection connection channel 901 is connected to the leak detector 15 via a leak detection valve 14 and a pipeline. The leak detector 15 is a helium mass spectrometer leak detector with a detection sensitivity ≥1×10⁻⁶. -10 Pa·m³ / s, the results are corrected by molecular weight calibration coefficient when detecting different media.

[0026] The lower end of the second sleeve 9 forms a seal with the side wall of the column 2. Specifically, a sealing ring 16 is installed between the inner wall of the second sleeve 9 and the side wall of the column 2 to seal the leak detection chamber. The sealing ring 16 is made of perfluoroether rubber (FFKM), with a maximum temperature resistance of 320℃ and high sealing reliability. However, the sealing ring 16 is not suitable for testing at a high temperature of 900℃. Therefore, the first sleeve 8 and the second sleeve 9 are installed to keep them away from the high-temperature testing area, reducing heat conduction and avoiding direct exposure to high temperatures. At the same time, a cooling channel 202 is installed in the lower part of the column 2, that is, in the section of the column away from the second end face 201 of the column 2, thus forming a cooling section. A water inlet valve 17 is installed at the inlet end of the cooling channel 202, and a water outlet valve 18 is installed at the outlet end of the cooling channel 202 to control the inflow and outflow of cooling water.

[0027] The sealing ring 16 of the aforementioned sealing and leak detection cavity is set on the cooling section. This reduces external heat conduction on the one hand, and the cooling channel 202 can cool the cooling section of the column 2 to control the temperature of the sealing ring 16, thereby ensuring that the sealing ring 16 can reliably seal.

[0028] In addition, the connection point between the leak detection connection channel 901 on the second sleeve 9 and the leak detection chamber is located in the cooling section of the column 2. Thus, at least a part of the second side gap 13 is also in the cooling section. If the gasket generates leaking gas and enters the leak detection chamber, it will pass through the second side gap 13 and the leak detection connection channel 901 before entering the leak detector 15, which can reduce the temperature of the leaking gas and reduce the high temperature impact on the leak detector 15.

[0029] In this embodiment, the side wall of the column base 2 is provided with a sealing groove, and the sealing ring 16 is engaged in the sealing groove. The end of the second sleeve 9 away from the first sleeve 8 (the lower end in this embodiment) is provided with an inner flange 902. During the leakage rate test, the sealing ring 16 is in close contact with the end face of the inner flange 902. If the inner flange 902 and the second sleeve 9 are an integral structure, the height of the sealing groove from the bottom of the column base 2 should be greater than the length of the second sleeve 9. Preferably, a pressure ring can be fixedly connected to the end of the second sleeve 9 to form the inner flange 902, which facilitates installation.

[0030] The operating temperature of the leak-proof sealing gasket 4 under test is controlled by the heating chamber 3, which is located in the test area. Specifically, the heating chamber 3 wraps around the pressure column 1, the first sleeve 8, and the column base 2. However, the heating chamber 3 does not completely wrap around the pressure column 1, the first sleeve 8, and the column base 2, but only partially. One end of the first sleeve 8, which connects to the second sleeve 9, extends out from the heating chamber 3. The heating chamber 3 is designed with two halves that fit together to wrap around the gasket. Overall, it consists of at least three layers: an outer metal shell 301, a middle insulation layer 302, and an inner heating wire layer 303.

[0031] In this embodiment, the outer metal shell 301 of the heating box 3 is made of cold-rolled steel plate, which is inexpensive and structurally robust, and can isolate the high temperature inside the box from external radiation. The middle insulation layer 302 is made of alumina ceramic fiber board, which has excellent insulation effect and prevents heat loss. The inner heating wire layer 303 uses nickel-chromium heating wire (Ni80Cr20), which provides uniform heating and allows for power adjustment to achieve precise temperature control from 20℃ to 900℃.

[0032] In addition, to accurately reflect the temperature changes at the leak-testing gasket 4 and sealing ring 16, this embodiment also includes a first temperature sensor 19, a second temperature sensor 20, a controller 21, and a display device 22. The first temperature sensor 19 is an S-type thermocouple, located near the first end face 101 of the pressure column 1, to reflect the operating temperature of the leak-testing gasket 4. The wires of the first temperature sensor 19 are connected through openings in the pressure column 1 and the heating chamber 3. During heating and insulation, asbestos or fiberglass paper is used to seal the pores to reduce heat loss. The first temperature sensor 19 is electrically connected to the controller 21, which controls the heating power of the heating chamber 3. The second temperature sensor 20 is a K-type thermocouple, located near the sealing ring 16 on the second sleeve 9. A blind hole is provided in the second sleeve 9 for installing the second temperature sensor 20. During installation, the thermocouple probe is embedded into the pre-drilled blind hole, and the gap is filled with high-temperature resistant ceramic sealant to fix the probe, reduce thermal resistance, and seal the tiny pores within the blind hole. The display thermometer, as a display device 22, is electrically connected to the second temperature sensor 20 and is used to display the temperature measured by the second temperature sensor 20.

[0033] Please combine Figure 3 and Figure 4 As shown, when using the gasket leakage rate testing device of the present invention for testing, the second sleeve 9 is fitted onto the column 2, and the sealing ring 16 is pressed into the sealing groove. The first sleeve 8 and the second sleeve 9 are then bolted together using the heat-insulating sealing gasket 11, and the gasket 4 to be tested is placed in the center of the second end face 201 of the column 2. At this time, the pressure column 1 and the first sleeve 8 are not yet connected. The sealing ring 16 is pre-compressed under the assembly force, and after elastic deformation, it generates a uniform "initial contact pressure" on the sealing surface, filling the microscopic unevenness of the sealing surface and forming an initial seal between the lower end of the second sleeve 9 and the column 2.

[0034] Then, the first sealing gasket 10 is placed on the top surface of the first sleeve 8, the pressure column 1 moves down, and the first end face 101 of the pressure column 1 contacts the leak-testing sealing gasket 4. At the same time, the first sleeve 8 is fixed to the pressure column 1 with bolts. At this time, the inner area of ​​the leak-testing sealing gasket 4 is connected to the leak-testing medium injection channel 102 on the pressure column 1, and the outer area of ​​the leak-testing sealing gasket 4 is connected to the leak-testing channel. Finally, the heating box 3 is wrapped and installed in place.

[0035] At the start of the test, heating is performed through heating chamber 3, and the heating power is controlled by controller 21 to the preset heating temperature measured by the first temperature sensor 19. The cooling section is cooled by controlling the water inlet valve 17 and water outlet valve 18 of the control column 2 to ensure that the temperature at the sealing ring 16 measured by the second temperature sensor 20 is within the safe range. After the temperature at each location stabilizes, a universal testing machine is used to apply a preset preload through the column 2 and maintain stability. The vent valve 5 is opened to fill the inner area of ​​the leak-testing gasket 4 with leak-testing medium, and the pressure is maintained for 5 minutes to eliminate fluctuations. The leak-testing valve 14 is opened, and the leakage rate of the leak-testing chamber is monitored by a helium mass spectrometer leak detector 15 to generate a "leakage rate-time" curve.

[0036] During the heating and loading process, the metal materials such as the pressure column 1, the first sleeve 8, and the second sleeve 9 undergo thermal expansion due to the increased temperature. This further increases the compression on the first sealing gasket 10 and the heat-insulating sealing gasket 11. The sealing specific pressure increases synchronously with the expansion, creating a thermal self-tightening effect, forcing the leaking medium from the test gasket to flow downwards only along a preset path. Simultaneously, the sealing ring 16 between the second sleeve 9 and the column 2 remains in a self-sealing state—the application of external loads acts on the inner or outer side of the sealing ring 16, pushing it towards the sealing surface. The contact pressure also increases synchronously with the load, creating a "pressure self-reinforcing" effect, ensuring that the contact pressure is always greater than the medium pressure, preventing the medium from penetrating the sealing surface, and achieving a reliable seal. Furthermore, the core reason why the sealing ring 16 can operate stably under high-temperature conditions up to 900℃ is the dual effect of the sleeve structure extending the heat insulation and real-time temperature measurement and water cooling. The first sleeve 8 and the second sleeve 9 extend the distance between the sealing ring 16 and the test area, and the two sleeves are connected by a heat-insulating sealing gasket 11, which effectively reduces the heat transfer efficiency and prevents the sealing ring 16 from directly bearing high-temperature radiation and conductive heat, thus reducing the impact of high temperature along the path. At the same time, the temperature change at the sealing ring 16 is monitored by the second temperature sensor 20. By controlling the cooling water flow entering the cooling section of the column 2, the heat is quickly removed, keeping the temperature of the sealing ring 16 below the safety threshold (taking the sealing ring 16 as a high-temperature resistant perfluoroether rubber as an example, the safety threshold is 300℃, with a 20℃ safety buffer reserved to adapt to the upper limit of 320℃), maintaining temperature stability. Finally, through the synergistic effect of the sleeve structure and water cooling, the problem of traditional seals being unable to adapt to high-temperature conditions is solved.

Claims

1. A device for testing the leakage rate of a sealing gasket, characterized in that, The device includes a pressure column, a column base, and a heating chamber. The pressure column has a first sleeve at its first end and a leak-testing medium injection channel inside. This channel forms a leak-testing medium injection port on the first end face of the pressure column. A test area for placing a leak-testing gasket is located between the first end face of the pressure column and the second end face of the column base. A first side gap is provided between the inner wall of the first sleeve and the side wall of the column base. A second sleeve is thermally insulated at one end of the first sleeve. A second side gap is provided between the inner wall of the second sleeve and the side wall of the column base. The first and second side gaps constitute a leak-testing cavity, which is connected to a leak detector. A section of the column base away from the second end face is a cooling section with an internal cooling channel. A sealing ring is provided between the second sleeve and the cooling section to seal the leak-testing cavity. The test area is located inside the heating chamber, and one end of the first sleeve connected to the second sleeve extends out from the heating chamber.

2. The gasket leakage rate testing device according to claim 1, characterized in that, The second sleeve is provided with a leak detection connection channel, which is connected to the leak detection chamber. The outlet of the leak detection connection channel is connected to the leak detector, and the connection point between the leak detection connection channel and the leak detection chamber is located in the cooling section.

3. The gasket leakage rate testing device according to claim 1, characterized in that, The first sleeve is detachably connected to the first end face of the pressure column.

4. The gasket leakage rate testing device according to claim 3, characterized in that, A flexible graphite composite gasket with an internal alloy skeleton is provided between the first sleeve and the first end face of the pressure column.

5. The gasket leakage rate testing device according to claim 1, characterized in that, The side wall of the column is provided with a sealing groove, and the sealing ring is locked in the sealing groove. The end of the second sleeve away from the first sleeve is provided with an inner flange. During the leakage rate test, the sealing ring is in close contact with the end face of the inner flange.

6. The gasket leakage rate testing device according to claim 1, characterized in that, A first temperature sensor is provided near the first end face of the pressure column. The first temperature sensor is electrically connected to the controller, which is used to control the heating power of the heating box.

7. The gasket leakage rate testing device according to claim 1, characterized in that, A second temperature sensor is provided on the second sleeve near the sealing ring. The second temperature sensor is electrically connected to a display device, which is used to display the temperature measured by the second temperature sensor.

8. The gasket leakage rate testing device according to claim 1, characterized in that, The heating box encloses the pressure column, the first sleeve, and a portion of the column base.

9. The gasket leakage rate testing device according to claim 1, characterized in that, The heating box includes an outer metal shell, a middle insulation layer, and an inner heating wire layer.

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