A multi-model adaptive low-temperature valve sealing performance testing device and method

Abstract

The application discloses a multi-model adaptive low-temperature valve sealing performance testing device and method, and belongs to the technical field of valve detection. The device comprises: a first upper end cover of a low-temperature thermostat, wherein a to-be-tested low-temperature valve is installed on the first upper end cover through a valve support device; the valve support device is in flexible sealing cooperation with a bellows through an adjusting screw, so that the installation height and centering of the to-be-tested low-temperature valve are controlled, and low-temperature valves of different specifications are adapted; the low-temperature thermostat surrounds a first cold screen and a second cold screen; the bottom of the to-be-tested low-temperature valve is connected with one end of a cold-lead bridge through a pipe clamp and is surrounded by the first cold screen; a GM refrigerating machine comprises two-stage cold heads arranged in the low-temperature thermostat; the second cold screen surrounds the two-stage cold heads; the other end of the cold-lead bridge is connected with the two-stage cold heads; three helium supply devices are connected with the inlet and outlet of the to-be-tested low-temperature valve and the low-temperature thermostat respectively; and a vacuum pump unit is connected with the low-temperature thermostat. The application realizes rapid adaptation and accurate testing of low-temperature valves of multiple models.

Description

Technical Field

[0001] This invention belongs to the field of valve testing technology, specifically relating to a multi-model adaptable cryogenic valve sealing performance testing device and method. Background Technology

[0002] As a key component controlling the flow of cryogenic fluids, the sealing performance of cryogenic valves is a core indicator for evaluating valve quality and determining system operating efficiency and safety. Especially in the fields of natural gas and ammonia storage and transportation, and liquefaction, the explosiveness and toxicity of the media place extremely stringent requirements on the sealing reliability of valves. Therefore, rigorous sealing performance tests must be conducted on valves at their actual operating temperatures before they leave the factory and during periodic maintenance.

[0003] Currently, testing the performance of cryogenic valves typically faces technical challenges such as poor versatility of testing equipment and insufficient accuracy in sealing tests. Specifically, traditional testing equipment is usually designed for valves of specific sizes, and its support, fixing, and heat exchange structures lack adjustability. When testing different valve models, complex mechanical modifications to the testing equipment are often required, resulting in long testing cycles, high costs, and an inability to meet the need for rapid testing of multiple models. Furthermore, sealing tests of cryogenic valves require operation in extremely low temperatures (such as the liquid helium temperature range of 4.2K), necessitating precise isolation of thermal loads from the environment. Existing testing equipment often connects to complex external piping systems, making operation cumbersome and resulting in low testing efficiency.

[0004] Therefore, designing a sealing performance testing device that can quickly adapt to various types of cryogenic valves has become a key technical challenge that the industry urgently needs to solve. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A multi-model adaptable cryogenic valve sealing performance testing device includes: a valve support device, a pipe clamp, a GM refrigerator, a cold bridge, a cryogenic thermostat, a first cold screen, a second cold screen, a vacuum pump unit, a helium supply device, and two helium mass spectrometer leak detectors.

[0007] The low-temperature valve to be tested is installed on the first upper end cover of the low-temperature thermostat via a valve support device. The valve support device controls the installation height and centering of the low-temperature valve to be tested through the flexible sealing cooperation between the adjusting screw and the bellows, and is suitable for low-temperature valves of different specifications.

[0008] The low-temperature thermostat completely surrounds the first and second cold screens;

[0009] The bottom of the cryogenic valve under test is connected to one end of the cold bridge via a pipe clamp and is surrounded by the first cold shield;

[0010] The GM refrigeration unit includes a primary cold head and a secondary cold head arranged from top to bottom within a low-temperature thermostat; a second cold shield surrounds the primary and secondary cold heads; and the other end of the cold-conducting bridge is connected to the secondary cold head.

[0011] The helium supply device, the first helium mass spectrometer leak detector, and the second helium mass spectrometer leak detector are respectively connected to the inlet and outlet of the cryogenic valve to be tested and to the cryogenic thermostat; the vacuum pump unit is connected to the cryogenic thermostat.

[0012] A method for testing the sealing performance of multi-model adaptable cryogenic valves, using the aforementioned multi-model adaptable cryogenic valve sealing performance testing device, comprising:

[0013] Step 1: After assembling all components of the multi-model adaptable cryogenic valve sealing performance testing device, conduct an airtightness test. Use a first helium mass spectrometer leak detector to check each welding point and flange connection to determine that the leakage rate meets the standard. Evacuate the inside of the cryogenic thermostat. Then install a certain model of cryogenic valve to be tested.

[0014] Step 2: Turn off the vacuum pump unit and start the GM refrigerator. Cool the first and second cold screens through the first-stage cold head. At the same time, the second-stage cold head cools the bottom of the low-temperature valve under test through the cold bridge.

[0015] Step 3: After the bottom temperature of the cryogenic valve under test reaches the set value and remains stable, close its valve disc and introduce room temperature helium into the inlet of the cryogenic valve through the helium supply device as a leak indicator gas; then, the first helium mass spectrometer leak detector detects the helium leakage rate at the outlet of the cryogenic valve; disconnect the second pipeline connecting the first helium mass spectrometer leak detector to the outlet of the cryogenic valve, and start the second helium mass spectrometer leak detector to detect the helium leakage rate inside the cryogenic thermostat;

[0016] Step 4: Restore normal pressure, replace with another model of cryogenic valve to be tested, and repeat steps 1 to 3 above to complete the sealing performance test of another model of cryogenic valve to be tested.

[0017] The present invention has the following beneficial effects:

[0018] (1) The invention enables rapid adaptation and precise positioning of multiple types of cryogenic valves: By setting an innovative adjustable valve support device, the invention can quickly adapt to cryogenic valves of different specifications; by using a graduated adjusting screw and a bellows with flexible sealing, the installation height and centering of the valve can be precisely controlled, ensuring that different types of valves can establish a stable and reliable thermal connection with the cold bridge, which greatly improves the testing flexibility and reduces tooling costs.

[0019] (2) Improved accuracy of sealing performance testing: The present invention provides a stable and uniform deep low temperature environment for valve testing through the efficient thermal connection of the two-stage cold head and the cold bridge. At the same time, the graded thermal shielding system composed of the first and second cold screens effectively isolates the heat radiation from the ambient temperature, ensuring that the valve body and sealing components can quickly and accurately reach and maintain their actual operating temperature.

[0020] (3) Avoids the drawback of repeatedly replacing the insulation layer of the cold shield: This invention adopts a detachable first cold shield composed of upper and lower cold shields connected by bolts. As a complete heat shield component, this cold shield can be stably reused in multiple test cycles. This is in stark contrast to the outdated process in traditional testing devices that requires destroying and re-wrapping multiple layers of insulation material every time the valve is disassembled or assembled, greatly saving the time and material cost of replacing the insulation material after each test and simplifying the operation process. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a multi-model adaptable cryogenic valve sealing performance testing device. 1-Cryogenic valve to be tested, 2-Valve support device, 3-Pipe clamp, 4-First flange, 5-GM refrigerator, 6-First-stage cold head, 7-Second-stage cold head, 8-Cooling bridge, 9-Cryogenic thermostat, H1-Helium supply device, H2-First helium mass spectrometer leak detector, H3-Second helium mass spectrometer leak detector, TS1-First cold shield, TS2-Second cold shield, L1-First pipeline, L2-Second pipeline, L3-Third pipeline, L4-Fourth pipeline, P1-Vacuum pump unit;

[0022] Figure 2 This is a structural diagram of the components of the cryogenic valve under test, where 1-the cryogenic valve under test, 2-valve support device, 3-pipe clamp, 12-adjusting screw, 13-upper adjusting nut, 14-lower adjusting nut, 15-upper flange, 16-lower flange, 17-bellows, 19-first upper end cover, Vo-outlet of the cryogenic valve under test, and Vi-inlet of the cryogenic valve under test.

[0023] Figure 3 This is a cross-sectional structural diagram of the valve support device, where 12-adjusting screw, 15-upper flange, 16-lower flange, 17-bellows, 18-split flange, 19-first upper end cover, and V1-valve seat of the low-temperature valve to be tested.

[0024] Figure 4 This is a structural diagram of a cold shield, where 4-first flange, 5-GM refrigeration unit, 10-second upper cover, 20-upper cold shield, 30-lower cold shield, TS1-first cold shield, and TS2-second cold shield. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] Please see Figure 1 , Figure 3 As shown, the present invention provides a multi-model adaptable cryogenic valve sealing performance testing device (hereinafter referred to as the device), including: valve support device 2, pipe clamp 3, GM (Gifford-McMahon) refrigerator 5, cold bridge 8, cryogenic thermostat 9, first cold screen TS1, second cold screen TS2, vacuum pump unit P1 helium supply device, and two helium mass spectrometer leak detectors.

[0027] The cryogenic valve 1 under test is mounted on the first upper cover 19 of the cryogenic thermostat 9 via a valve support device 2. The valve support device 2, through the flexible sealing cooperation between the adjusting screw 12 and the bellows 17, precisely controls the installation height and alignment of the cryogenic valve 1 under test, ensuring that different models of cryogenic valves can establish a stable and reliable thermal connection with the cold bridge 8, greatly improving testing flexibility and reducing tooling costs. The cryogenic thermostat 9 completely surrounds the first cold shield TS1 and the second cold shield TS2. The bottom of the cryogenic valve 1 under test is connected to one end of the cold bridge 8 via a pipe clamp 3, and the bottom of the cryogenic valve 1 is surrounded by the first cold shield TS1. The first cold shield TS1 is fixedly connected to the first upper cover 19 of the cryogenic thermostat 9 via a support rod. The GM refrigeration unit 5 includes a primary cold head 6 and a secondary cold head 7 arranged from top to bottom within the cryogenic thermostat 9. The primary cold head 6 and the secondary cold head 7 are fixed to the cryogenic thermostat 9 via the first upper cover 19; the other end of the cold bridge 8 is connected to the secondary cold head 7. The second cold shield TS2 is fixedly connected to the first flange 4 on the upper part of the first-stage cold head 6, and surrounds the first-stage cold head 6 and the second-stage cold head 7. The helium supply device H1 is connected to the inlet Vi of the cryogenic valve to be tested through the first pipeline L1; the first helium mass spectrometer leak detector H2 is connected to the outlet Vo of the cryogenic valve to be tested through the second pipeline L2; the second helium mass spectrometer leak detector H3 is connected to the cryogenic thermostat 9 through the third pipeline L3; and the vacuum pump unit P1 is connected to the cryogenic thermostat 9 through the fourth pipeline L4.

[0028] like Figure 2 , Figure 3 As shown, the valve support device 2 includes an adjusting screw 12, an upper flange 15, a lower flange 16, a bellows 17, and a split flange 18.

[0029] The upper flange 15 mates with the split flange 18 and is installed on the valve seat V1 of the cryogenic valve under test. The upper flange 15 is fixed to the lower flange 16, and then fixed to the first upper end cover 19 by the adjusting screw 12. The adjusting screw 12 includes an upper adjusting nut 13 and a lower adjusting nut 14 respectively disposed on the upper and lower surfaces of the lower flange 16, used to adjust the installation position of the lower flange 16. Different cryogenic valves 1 under test have different valve stem lengths and diameters. For cryogenic valves 1 under test of different lengths, the bellows 17 is a welded metal bellows, which can meet the requirements of large displacement. According to the length of the valve stem, the adjusting screw 12 can be used to compress or stretch the bellows 17 to adjust the lower flange 16 to a suitable position, ensuring that the valve seat V1 of the cryogenic valve under test is installed in the preset position. For cryogenic valves 1 under test of different diameters, the largest commonly used cryogenic valve model is used to open the mounting hole on the first upper end cover 19, and then the bellows 17 is used to seal it to the lower flange 16. The above methods enable the testing of the sealing performance of different cryogenic valves.

[0030] The bellows 17 is disposed between the lower flange 16 and the first upper end cover 19, and is fixedly connected to the lower flange 16 and the first upper end cover 19 respectively. It is used to seal the low-temperature thermostat 9 and the low-temperature valve 1 under test for displacement compensation. Specifically, during the cooling process, the material of the low-temperature valve 1 under test may deform / displace due to the temperature difference, which can compensate for the deformation / displacement of the valve under large temperature difference. In addition, during the installation of different low-temperature valves 1 under test, displacement compensation can be performed according to the length of different valve stems.

[0031] Among them, such as Figure 4 As shown, the first cold screen TS1 and the second cold screen TS2 share the second upper cover 10. The first cold screen TS1 includes an upper cold screen 20 and a lower cold screen 30, which are detachably connected by bolts.

[0032] The upper flange 15 has a sealing groove on the side that contacts the valve seat V1 of the low-temperature valve to be tested, and a positioning groove on the side that contacts the split flange 18.

[0033] The lower flange 16 has a sealing groove and a positioning groove on the side that contacts the upper flange 15.

[0034] Among them, the corrugated pipe 17 is a welded metal corrugated pipe.

[0035] The adjusting screw 12 is equipped with a scale.

[0036] The cooling bridge 8 has a waist hole and is connected to the pipe clamp 3 by a flexible connection.

[0037] This invention further provides a method for testing the sealing performance of multi-model adaptable cryogenic valves, including:

[0038] Step 1: After assembling all components of the multi-model adaptable cryogenic valve sealing performance testing device, perform an airtightness test on the device. Use a first helium mass spectrometer (H2) to inspect each weld point and flange connection, ensuring the leakage rate meets the standard (leakage rate ≤ 1×10⁻⁶). -9 Pa·m 3 / s). The vacuum pump unit P1 evacuates the interior of the cryogenic thermostat 9 until the internal air pressure is ≤1×10⁻⁶. -5 Pa; then install a certain model of cryogenic valve 1 to be tested.

[0039] Step 2: Turn off vacuum pump unit P1 and start GM refrigerator 5. The first-stage cold head 6 cools the temperature of the first cold shield TS1 and the second cold shield TS2 to approximately 50K, effectively shielding the thermal radiation from the 300K environment on the cryogenic valve 1 under test. At the same time, the second-stage cold head 7 cools the pipe clamp 3 through the heat conduction via the cold bridge 8, thereby cooling the bottom of the cryogenic valve 1 under test.

[0040] Step 3: After the bottom temperature of the cryogenic valve 1 under test reaches the set value of 4.2K and remains stable, close its valve disc. Introduce room temperature helium gas as a leak indicator gas through the helium supply device H1 and the first pipeline L1 to the inlet Vi of the cryogenic valve under test. Then, turn on the first helium mass spectrometer leak detector H2 to detect the helium leakage rate at the outlet Vo of the cryogenic valve under test in order to test its internal sealing performance. After completing the internal sealing performance test, disconnect the second pipeline L2 connected to the outlet Vo of the cryogenic valve under test, and start the second helium mass spectrometer leak detector H3 to detect the helium leakage rate inside the cryogenic thermostat 9 in order to test its external sealing performance.

[0041] Step 4: Return the multi-model adaptable cryogenic valve sealing performance testing device to normal pressure, disassemble the cryogenic thermostat 9 and the lower cold screen 30 of the first cold screen TS1, loosen the pipe clamp 3, and then loosen the connecting bolts of the upper flange 15 and the lower flange 16 in sequence. Adjust the upper adjusting nut 13 and the lower adjusting nut 14 to the appropriate position, and then loosen the screw connection between the upper flange 15 and the split flange 18. Remove the tested cryogenic valve 1 as a whole, replace it with another model of cryogenic valve 1, and repeat steps 1 to 3 above to complete the sealing performance test of another model of cryogenic valve 1.

[0042] The above description is merely an embodiment of the present invention and does not limit the scope of the invention. Any equivalent structural or procedural transformations made based on the description and drawings of this invention, or direct or indirect applications in other related system fields, are similarly included within the protection scope of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A multi-model adaptable cryogenic valve sealing performance testing device, characterized in that, include: Valve support device, pipe clamp, GM refrigerator, cold bridge, low temperature thermostat, first cold screen, second cold screen, vacuum pump unit, helium supply device and two helium mass spectrometer leak detectors; The low-temperature valve to be tested is installed on the first upper end cover of the low-temperature thermostat via a valve support device. The valve support device controls the installation height and centering of the low-temperature valve to be tested through the flexible sealing cooperation between the adjusting screw and the bellows, and is suitable for low-temperature valves of different specifications. The low-temperature thermostat completely surrounds the first and second cold screens; The bottom of the cryogenic valve under test is connected to one end of the cold bridge via a pipe clamp and is surrounded by the first cold shield; The GM refrigeration unit includes a primary cold head and a secondary cold head arranged from top to bottom within a low-temperature thermostat; a second cold shield surrounds the primary and secondary cold heads; and the other end of the cold-conducting bridge is connected to the secondary cold head. The helium supply device, the first helium mass spectrometer leak detector, and the second helium mass spectrometer leak detector are respectively connected to the inlet and outlet of the cryogenic valve to be tested and to the cryogenic thermostat; the vacuum pump unit is connected to the cryogenic thermostat.

2. The multi-model adaptable cryogenic valve sealing performance testing device according to claim 1, characterized in that, The first cold shield is fixedly connected to the first upper cover of the low-temperature thermostat via a support rod; the second cold shield is fixedly connected to the first flange on the upper part of the first-stage cold head; the first-stage cold head and the second-stage cold head are fixed inside the low-temperature thermostat via the first upper cover.

3. The multi-model adaptable cryogenic valve sealing performance testing device according to claim 1, characterized in that, The valve support device includes an adjusting screw, an upper flange, a lower flange, a bellows, and a split flange; The upper flange mates with the split flange and is installed on the valve seat of the cryogenic valve to be tested. The upper flange is fixed to the lower flange and then fixed to the first upper end cover by adjusting screws. The adjusting screws include upper and lower adjusting nuts respectively set on the upper and lower surfaces of the lower flange, used to adjust the installation position of the lower flange. A bellows is set between the lower flange and the first upper end cover, and is fixedly connected to the lower flange and the first upper end cover respectively, used to seal the cryogenic thermostat and to compensate for the displacement of the cryogenic valve to be tested.

4. The multi-model adaptable cryogenic valve sealing performance testing device according to claim 3, characterized in that, The side of the upper flange that contacts the valve seat of the cryogenic valve under test is provided with a sealing groove, and the side that contacts the split flange is provided with a positioning groove.

5. The multi-model adaptable cryogenic valve sealing performance testing device according to claim 3, characterized in that, The side of the lower flange that contacts the upper flange is provided with a sealing groove and a positioning groove.

6. The multi-model adaptable cryogenic valve sealing performance testing device according to claim 1 or 3, characterized in that, The first and second cold screens share a second upper cover; the first cold screen includes a detachably connected upper cold screen and a lower cold screen.

7. The multi-model adaptable cryogenic valve sealing performance testing device according to claim 1, characterized in that, The adjusting screw has a scale.

8. The multi-model adaptable cryogenic valve sealing performance testing device according to claim 1, characterized in that, The corrugated pipe is a welded metal corrugated pipe.

9. The multi-model adaptable cryogenic valve sealing performance testing device according to claim 1, characterized in that, The cooling bridge has a waist hole and a flexible connection with the pipe clamp.

10. A method for testing the sealing performance of multi-model adaptable cryogenic valves, used in the multi-model adaptable cryogenic valve sealing performance testing device as described in any one of claims 1 to 9, characterized in that, include: Step 1: After assembling all components of the multi-model adaptable cryogenic valve sealing performance testing device, conduct an airtightness test. Use a first helium mass spectrometer leak detector to check each welding point and flange connection to determine that the leakage rate meets the standard. Vacuum the inside of the cryogenic thermostat. Then, a certain model of cryogenic valve to be tested was installed; Step 2: Turn off the vacuum pump unit and start the GM refrigerator. Cool the first and second cold screens through the first-stage cold head. At the same time, the second-stage cold head cools the bottom of the low-temperature valve under test through the cold bridge. Step 3: After the bottom temperature of the cryogenic valve under test reaches the set value and remains stable, close its valve disc and introduce room temperature helium into the inlet of the cryogenic valve through the helium supply device as a leak indicator gas; then, the first helium mass spectrometer leak detector detects the helium leakage rate at the outlet of the cryogenic valve; disconnect the second pipeline connecting the first helium mass spectrometer leak detector to the outlet of the cryogenic valve, and start the second helium mass spectrometer leak detector to detect the helium leakage rate inside the cryogenic thermostat; Step 4: Restore normal pressure, replace with another model of cryogenic valve to be tested, and repeat steps 1 to 3 above to complete the sealing performance test of another model of cryogenic valve to be tested.

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