A general-purpose device and method for testing the heat leakage performance of cryogenic valves

Abstract

This invention discloses a universal cryogenic valve heat leakage performance testing device and method, belonging to the field of valve testing technology. It includes: a cryogenic valve to be tested installed on the upper end of a cryogenic thermostat; the valve seat of the cryogenic valve to be tested connected to a valve heat exchanger via a pipe clamp; a first cold shield surrounding the valve seat; a valve support including a first flange adapted to different cryogenic valves to be tested; two cold shields installed inside the cryogenic thermostat, both with modular sidewall designs, flexibly adaptable to different cryogenic valves to be tested; two heaters connected to a temperature controller respectively installed on the heat sink and the pipe clamp; a GM refrigeration unit installed inside the cryogenic thermostat, including two-stage cold heads; a second cold shield surrounding the two-stage cold heads; a secondary cold head with a secondary heat exchanger connected to the valve heat exchanger; a helium supply device connected to the primary heat exchanger on the primary cold head; a helium recovery device connected to the valve heat exchanger; and a vacuum pump unit connected to the cryogenic thermostat. This invention improves testing efficiency and device utilization.

Description

Technical Field

[0001] This invention belongs to the field of valve testing technology, specifically relating to a general-purpose device and method for testing the heat leakage performance of cryogenic valves. Background Technology

[0002] Cryogenic valves, as key components in cryogenic systems, are widely used in liquefied natural gas, liquid ammonia storage and transportation systems, and nuclear fusion devices. Their heat leakage performance is a core indicator for evaluating valve quality and affecting system energy efficiency and operational stability.

[0003] Currently, testing techniques for the heat leakage performance of cryogenic valves still face the following technical challenges: First, the testing equipment lacks versatility. Existing testing equipment is typically designed for specific valve models, with fixed support structures, cooling interfaces, and thermal boundary conditions, lacking effective adaptability and adjustability. Second, heat leakage paths are difficult to separate and quantify. Under actual operating conditions, valve heat leakage usually includes solid-state heat conduction along the valve stem and support structure, as well as multiple heat leakage paths caused by radiation and residual gas conduction. Existing methods cannot effectively separate the heat leakage from different paths, resulting in test results that cannot accurately reflect the valve's inherent performance. Third, testing efficiency is low. Traditional heat leakage tests often rely on liquid helium immersion or direct cooling with large-diameter refrigerators. These systems have large heat capacities, slow cooling, high energy consumption, and long cycles.

[0004] Therefore, developing a general-purpose cryogenic valve heat leakage performance testing device with the ability to separate and measure heat leakage paths and high testing efficiency has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

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

[0006] A general-purpose cryogenic valve heat leakage performance testing device includes: valve support, pipe clamp, valve heat exchanger, GM refrigerator, cryogenic thermostat, temperature controller, first heater and second heater respectively connected to the temperature controller, first cold screen and second cold screen installed in the cryogenic thermostat, vacuum pump unit, helium supply device and helium recovery device.

[0007] The low-temperature valve to be tested is mounted on the upper end of the low-temperature thermostat via a valve support; the valve seat of the low-temperature valve to be tested is connected to the valve heat exchanger via a pipe clamp; and the first cold shield surrounds the valve seat.

[0008] The valve support includes an interface size that adapts to different cryogenic valves under test and a removable first flange;

[0009] Both the first and second cold shields adopt a modular sidewall design, which is composed of multiple detachable sidewalls spliced ​​together. By replacing the sidewalls of different specifications, they can be flexibly adapted to the low-temperature valves under test of different heights.

[0010] The first heater and the second heater are respectively installed on the heat sink and pipe clamp of the cryogenic valve to be tested;

[0011] The GM refrigeration unit is installed inside a low-temperature thermostat, including a primary cold head and a secondary cold head; a second cold shield surrounds the primary and secondary cold heads; the secondary cold head is equipped with a secondary heat exchanger connected to a valve heat exchanger;

[0012] The helium supply unit is connected to the primary heat exchanger installed on the primary cold head, the helium recovery unit is connected to the valve heat exchanger, and the vacuum pump unit is connected to the cryogenic thermostat.

[0013] A general-purpose method for testing the heat leakage performance of cryogenic valves, using the aforementioned general-purpose cryogenic valve heat leakage performance testing device, comprising:

[0014] Step 1: Install the low-temperature valve to be tested. After confirming that all components of the general-purpose low-temperature valve heat leakage performance testing device based on GM refrigeration unit are connected correctly, start the vacuum pump unit to evacuate the inside of the low-temperature thermostat.

[0015] Step 2: Introduce ambient temperature helium into the primary heat exchanger via a helium supply device. After the helium temperature drops to the set temperature, it flows from the primary heat exchanger to the secondary heat exchanger, where the temperature further decreases until the helium liquefies. Liquid helium flows from the secondary heat exchanger to the valve heat exchanger, where it cools the pipe clamp via heat conduction, thereby cooling the valve seat to a subcooled state. Record the temperature value measured by the second temperature sensor located on the pipe clamp. The heated liquid helium flows back from the valve heat exchanger to the secondary heat exchanger for further cooling and liquefaction.

[0016] Step 3: Conduct heat leakage performance testing on the cryogenic valve to be tested, including:

[0017] Measure the first heat loss along the path from the heat sink at a first temperature to the valve seat at a second temperature. ; Measure the second heat loss along the path from the valve support with a third temperature to the valve seat with a second temperature. Based on the first heat loss With the second heat loss To assess whether the heat leakage performance of the low-temperature valve under test meets the requirements;

[0018] Step 4: After the test, helium flow to the helium recovery device; disassemble the cryogenic valve to be tested, replace it with another type of cryogenic valve and repeat steps 1 to 3.

[0019] The present invention has the following beneficial effects:

[0020] (1) This invention achieves rapid adaptation to different models of cryogenic valves through a modularly designed valve support structure and a split-type cold shield structure. Specifically, the valve support structure adopts a detachable first flange connection, and different specifications of the first flange can be replaced according to the interface size of the valve under test; the first cold shield is composed of multiple detachable side walls spliced ​​together by bolts. When testing valves of different heights, side walls of different lengths can be replaced, or the operation can be completed by opening only the front side wall when disassembling the valve, without the need to disassemble the cold shield as a whole. This design effectively solves the problems of traditional testing devices relying on special tooling and difficulty in changing models, significantly improves testing efficiency and device utilization, and provides a universal testing platform for valve production quality inspection and R&D comparison.

[0021] (2) By adopting a two-stage pre-cooling helium gas circulation cooling method driven by a GM refrigerator, the present invention avoids the problem of slow cooling caused by contact thermal resistance and material limitations in solid cooling, effectively eliminates the local hot spots or insufficient cooling capacity that may occur in solid cooling, and provides a uniform, stable and efficient deep low temperature environment for valves.

[0022] (3) This invention constructs a compact and economical closed-loop refrigeration system by using a GM refrigerator instead of the traditional liquid helium immersion cooling method. Compared with the bulky Dewar system and complex liquid helium transport process in liquid helium immersion testing, this invention does not require frequent replenishment of liquid helium, has a fast cooling speed after startup, and significantly shortens the test preparation time. At the same time, the device has a built-in helium recovery system, realizing the recycling of helium working fluid and greatly reducing liquid helium consumption and overall testing costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the general-purpose low-temperature valve heat leakage performance testing device of the present invention;

[0024] Figure 2 This is a structural diagram of a split-type cold screen (first cold screen and second cold screen);

[0025] Figure 3 This is a schematic diagram of a valve heat exchanger.

[0026] Figure 4 This is a schematic cross-sectional view of a secondary heat exchanger.

[0027] Among them, 1-the cryogenic valve to be tested, 2-valve support, 3-pipe clamp, 4-valve heat exchanger, 5-GM refrigerator, 6-first-stage cold head, 7-first-stage heat exchanger, 8-second-stage cold head, 9-second-stage heat exchanger, 10-cryogenic thermostat, 11-temperature controller, 12-cold shield top cover, 13-first sidewall, 14-second sidewall, 15-third sidewall, 16-flow channel, 17-liquid helium tank, 18-pipe interface, 19-fin, 101-heat sink, 102-valve seat. 201-Cover, 202-First flange, 1001-Second flange, L1-First pipeline, L2-Second pipeline, L3-Third pipeline, L4-Fourth pipeline, L5-Fifth pipeline, L6-Sixth pipeline, T1-First temperature sensor, T2-Second temperature sensor, H1-First heater, H2-Second heater, TS1-First cold shield, TS2-Second cold shield, P-Vacuum pump unit, Z1-Helium supply device, Z2-Helium recovery device. Detailed Implementation

[0028] 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.

[0029] Please see Figure 1 As shown, the present invention provides a universal cryogenic valve heat leakage performance testing device, comprising: valve support 2, pipe clamp 3, valve heat exchanger 4, GM refrigerator 5 (a common cryogenic refrigerator), primary heat exchanger 7, secondary heat exchanger 9, cryogenic thermostat 10, temperature controller 11, first heater H1 and second heater H2 respectively connected to temperature controller 11, first cold shield TS1 and second cold shield TS2 installed in cryogenic thermostat 10, vacuum pump unit P, helium supply device Z1 and helium recovery device Z2.

[0030] The low-temperature valve 1 to be tested is installed on the upper end of the low-temperature thermostat 10 through the valve support 2; the valve seat 102 of the low-temperature valve 1 to be tested is connected to the valve heat exchanger 4 through the pipe clamp 3; the first cold screen TS1 is fixed inside the low-temperature thermostat 10 and surrounds the valve seat 102 of the low-temperature valve 1 to be tested.

[0031] The first heater H1 and the second heater H2 are respectively installed on the heat sink 101 and the pipe clamp 3.

[0032] The GM refrigeration unit 5 is installed inside the low-temperature thermostat 10, including a primary cold head 6 and a secondary cold head 8; a second cold shield TS2 surrounds the primary cold head 6 and the secondary cold head 8; a secondary heat exchanger 9 is installed on the secondary cold head 8, and the secondary heat exchanger 9 is connected to the valve heat exchanger 4.

[0033] The helium supply device Z1 is connected to the primary heat exchanger 7 installed on the primary cold head 6, the helium recovery device Z2 is connected to the valve heat exchanger 4, and the vacuum pump unit P is connected to the low-temperature thermostat 10.

[0034] The valve support 2 includes a housing 201 and a first flange 202. The cryogenic valve 1 to be tested is connected to the first flange 202 through the housing 201. The first flange 202 is installed on the second flange 1001 of the cryogenic thermostat 10. The first flange 202 is a detachable flange, and different specifications of the first flange 202 can be replaced according to the interface size of the cryogenic valve 1 to be tested.

[0035] The valve seat 102 of the cryogenic valve 1 under test is connected to the valve heat exchanger 4 via a pipe clamp 3, and the valve seat 102 is surrounded by a first cold shield TS1. The first cold shield TS1 is fixedly connected to a second flange 1001 via a support rod. The cryogenic valve 1 under test is equipped with a heat sink 101, which is connected to the upper cover plate 12 of the cold shield. A first heater H1 is installed on the heat sink 101, and a second heater H2 is installed on the pipe clamp 3. Both the first heater H1 and the second heater H2 are electrically connected to a temperature controller 11.

[0036] The GM refrigeration unit 5 includes a primary cold head 6 and a secondary cold head 8, mounted on the second flange 1001 of the cryogenic thermostat 10. A primary heat exchanger 7 is installed on the primary cold head 6, and a secondary heat exchanger 9 is installed on the secondary cold head 8. The primary cold head 6 is connected to the upper cover plate 12 of the cold shield. The second cold shield TS2 surrounds the primary cold head 6, the secondary cold head 8, the primary heat exchanger 7, and the secondary heat exchanger 9. The cryogenic thermostat 10 completely surrounds the first cold shield TS1 and the second cold shield TS2.

[0037] Helium supply unit Z1 is connected to primary heat exchanger 7 via first pipeline L1, helium recovery unit Z2 is connected to valve heat exchanger 4 via fifth pipeline L5, and vacuum pump unit P is connected to cryogenic thermostat 10 via sixth pipeline L6. Second pipeline L2 connects primary heat exchanger 7 and secondary heat exchanger 9, third pipeline L3 connects secondary heat exchanger 9 and valve heat exchanger 4, and fourth pipeline L4 connects secondary heat exchanger 9 and fifth pipeline L5.

[0038] Among them, such as Figure 3As shown, the valve heat exchanger 4 has multiple refrigerant flow channels 16 inside. The cross-section of each flow channel 16 is circular at its center, and multiple radially extending ribbed channels further increase the heat exchange area. A first temperature sensor T1 is located at the heat sink 101 to monitor its temperature change; a second temperature sensor T2 is located on the pipe clamp 3 to measure its temperature change. Since the temperature of the pipe clamp 3 is close to the temperature of the valve seat 102, the temperature change of the valve seat 102 can be indirectly obtained through the temperature change of the pipe clamp 3.

[0039] The primary heat exchanger 7 is made of high thermal conductivity oxygen-free copper and has pipe interfaces and an internal helium flow channel.

[0040] Among them, such as Figure 4 As shown, the secondary heat exchanger 9 is made of high thermal conductivity oxygen-free copper and is connected to a liquid helium tank 17 for storing liquid helium. The surface of the liquid helium tank 17 is provided with several pipe interfaces 18, and its interior is provided with multiple fins 19.

[0041] The first cold shield TS1 and the second cold shield TS2 both adopt a modular sidewall design, consisting of multiple detachable sidewall segments. By replacing different specifications of the sidewall modules, they can flexibly adapt to cryogenic valves of different heights under test. Specifically, the first cold shield TS1 and the second cold shield TS2 are assembled from multiple detachable sidewalls using bolts (or other methods). When testing cryogenic valves 1 of different heights, sidewalls of different lengths can be replaced. Furthermore, when disassembling the cryogenic valve 1, only the third sidewall 15 needs to be opened to complete the operation, without the need to disassemble the entire cold shield. Figure 2 As shown, the first cold screen TS1 and the second cold screen TS2 share the cold screen top cover plate 12 and the first side wall 13. The second cold screen TS2 is formed by the second side wall 14, the first side wall 13 and the cold screen top cover plate 12; the first cold screen TS1 is formed by the first side wall 13, the cold screen top cover plate 12 and the third side wall 15; the outer surfaces of the first cold screen TS1 and the second cold screen TS2 are covered with a heat insulation layer.

[0042] The heat sink 101 and the upper cover plate 12 of the cold screen are connected by a copper braided strip to obtain cooling.

[0043] This invention further provides a general-purpose method for testing the heat leakage performance of cryogenic valves, comprising the following steps:

[0044] Step 1: Install the cryogenic valve 1 to be tested. After confirming that all components of the universal cryogenic valve heat leakage performance testing device based on GM refrigeration unit 5 are connected correctly, start the vacuum pump unit P to evacuate the cryogenic thermostat 10 until the pressure is ≤1×10⁻⁶. -5 Pa.

[0045] Step 2: Room temperature helium is introduced into the primary heat exchanger 7 via the helium supply device Z1 and the first pipeline L1. After the helium temperature drops to the set temperature (approximately 50K), it flows from the primary heat exchanger 7 to the secondary heat exchanger 9 via the second pipeline L2, where the helium temperature further drops to approximately 4.2K and liquefies. Subsequently, the liquid helium flows from the secondary heat exchanger 9 to the valve heat exchanger 4 via the third pipeline L3. The valve heat exchanger 4 cools the pipe clamp 3 through heat conduction, thereby cooling the valve seat 102 to a subcooled state. The temperature value measured by the second temperature sensor T2 installed on the pipe clamp 3 is recorded. The heated liquid helium flows back from valve heat exchanger 4 to secondary heat exchanger 9 via the fourth pipeline L4 for further cooling and liquefaction.

[0046] Step 3: Conduct a heat leakage performance test on the cryogenic valve 1 to be tested, including:

[0047] First test: Measure the first heat loss along the path from heat sink 101 at 80K to valve seat 102 at 4.2K. ;

[0048] Second test: Measure the second heat loss along the path from valve support 2 at 300K to valve seat 102 at 4.2K. ;

[0049] The first test includes: activating the temperature controller 11 to control the first heater H1 to heat the heat sink 101 to 80K and maintain a stable temperature, and recording the temperature value measured by the first temperature sensor T1 located on the heat sink 101. The first preset heating power is applied to the second heater H2 by the temperature controller 11. =2W, so that the temperature of the valve seat 102 is kept stable at 4.2K, and the temperature value measured by the second temperature sensor T2 at this time is recorded. The temperature value measured by the first temperature sensor T1 Because of the first preset heating power It's very small, and its effect on the temperature of heat sink 101 is negligible, so ;

[0050] The first heat loss is calculated based on the following relationship. :

[0051] ;

[0052] ;

[0053] In the formula, R1 is the first thermal resistance (the thermal resistance of the wire, valve stem and valve seat 102 of the low-temperature valve 1 under test, pipe clamp 3, heat sink 101 and other parts in the first test), and the unit is K / W. for The difference, in units of K; for The difference is expressed in K.

[0054] By combining the equations, we can obtain:

[0055] ;

[0056] The second test includes: disconnecting the flexible connection between the heat sink 101 and the upper cover plate 12 of the cold screen; repeating step 2 and recording the temperature value measured by the second temperature sensor T2 at this time. The second preset heating power is applied to the second heater H2 by the temperature controller 11. =4W, keeping the temperature of valve seat 102 stable at 4.2K, and record the temperature value measured by the second temperature sensor T2. Since room temperature is relatively stable, it can be assumed to be a constant value. Based on the calculation of the first heat loss The second heat loss is calculated using a similar principle. ;

[0057] ;

[0058] ;

[0059] In the formula, for The value is in K; for The value is in K. R2 is the second thermal resistance (the thermal resistance of the wires, valve stem and valve seat 102 of the low-temperature valve 1 under test, pipe clamp 3, heat sink 101 and other parts in the second test).

[0060] By combining the equations, we can obtain:

[0061] ;

[0062] Based on the first heat loss With the second heat loss The heat leakage performance of the cryogenic valve 1 under test is evaluated to determine whether it meets the required specifications; wherein, the temperature controller 11 applies a first preset heating power to the second heater H2. The range is 1-3W, with the second preset heating power. The range is 1-10W.

[0063] Step 4: After the test, helium flows through the fifth pipeline L5 to the helium recovery device Z2 for recovery; then, disassemble the cryogenic valve 1 to be tested, replace it with another model of cryogenic valve 1 to be tested, and repeat steps 1 to 3 to complete the heat leakage performance test of other models of cryogenic valve 1 to be tested.

[0064] 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 universal device for testing the heat leakage performance of cryogenic valves, characterized in that, include: Valve support, pipe clamp, valve heat exchanger, GM refrigerator, low temperature thermostat, temperature controller, first heater and second heater connected to the temperature controller respectively, first cold screen and second cold screen installed in the low temperature thermostat, vacuum pump unit, helium supply device and helium recovery device. The low-temperature valve to be tested is mounted on the upper end of the low-temperature thermostat via a valve support; the valve seat of the low-temperature valve to be tested is connected to the valve heat exchanger via a pipe clamp; and the first cold shield surrounds the valve seat. The valve support includes an interface size that adapts to different cryogenic valves under test and a removable first flange; Both the first and second cold shields adopt a modular sidewall design, which is composed of multiple detachable sidewalls spliced ​​together. By replacing the sidewalls of different specifications, they can be flexibly adapted to the low-temperature valves under test of different heights. The first heater and the second heater are respectively installed on the heat sink and pipe clamp of the cryogenic valve to be tested; The GM refrigeration unit is installed inside a low-temperature thermostat, including a primary cold head and a secondary cold head; a second cold shield surrounds the primary and secondary cold heads; the secondary cold head is equipped with a secondary heat exchanger connected to a valve heat exchanger; The helium supply unit is connected to the primary heat exchanger installed on the primary cold head, the helium recovery unit is connected to the valve heat exchanger, and the vacuum pump unit is connected to the cryogenic thermostat.

2. The universal cryogenic valve heat leakage performance testing device according to claim 1, characterized in that, The valve support includes a housing and a first flange; the cryogenic valve under test is connected to the first flange through the housing, and the first flange is installed on the second flange of the cryogenic thermostat.

3. The universal cryogenic valve heat leakage performance testing device according to claim 1, characterized in that, The low-temperature valve under test is equipped with a heat sink, which is connected to the upper cover plate of the cold shield.

4. The universal cryogenic valve heat leakage performance testing device according to claim 1, characterized in that, The first-stage cold head is connected to the top cover of the cold shield; the second cold shield surrounds the first-stage cold head, the second-stage cold head, the first-stage heat exchanger, and the second-stage heat exchanger.

5. The universal cryogenic valve heat leakage performance testing device according to claim 1, characterized in that, The helium supply device is connected to the primary heat exchanger via the first pipeline, the helium recovery device is connected to the valve heat exchanger via the fifth pipeline, and the vacuum pump unit is connected to the cryogenic thermostat via the sixth pipeline; the second pipeline connects the primary heat exchanger and the secondary heat exchanger, the third pipeline connects the secondary heat exchanger and the valve heat exchanger, and the fourth pipeline connects the secondary heat exchanger and the fifth pipeline.

6. The universal cryogenic valve heat leakage performance testing device according to claim 1, characterized in that, The valve heat exchanger has multiple refrigerant channels inside. The cross-section of each channel is circular at the center and extends radially outwards into multiple radial rib-shaped channels.

7. The universal cryogenic valve heat leakage performance testing device according to claim 1, characterized in that, Also includes: A first temperature sensor and a second temperature sensor; the first temperature sensor is installed on the heat sink to monitor temperature changes in the heat sink. The second temperature sensor is installed on the pipe clamp to measure the temperature change of the pipe clamp, thereby indirectly obtaining the temperature change of the valve seat through the temperature change of the pipe clamp.

8. The universal cryogenic valve heat leakage performance testing device according to claim 1, characterized in that, The secondary heat exchanger is made of high thermal conductivity oxygen-free copper and is connected to a liquid helium tank for storing liquid helium. The surface of the liquid helium tank is equipped with several pipe interfaces and multiple fins inside.

9. The universal cryogenic valve heat leakage performance testing device according to claim 1, characterized in that, The first and second cold screens are assembled from multiple detachable sidewalls; the first and second cold screens share the top cover plate and the first sidewall. The first cold screen is formed by the first side wall, the upper cover plate of the cold screen and the third side wall; The second cold screen is formed by the second side wall, the first side wall, and the upper cover plate of the cold screen; The outer surfaces of the first and second cold screens are covered with an insulation layer.

10. A general-purpose method for testing the heat leakage performance of cryogenic valves, used in the general-purpose cryogenic valve heat leakage performance testing apparatus as described in any one of claims 1 to 9, characterized in that, include: Step 1: Install the low-temperature valve to be tested. After confirming that all components of the general-purpose low-temperature valve heat leakage performance testing device are connected correctly, start the vacuum pump unit to evacuate the inside of the low-temperature thermostat. Step 2: Introduce ambient temperature helium into the primary heat exchanger via a helium supply device. After the helium temperature drops to the set temperature, it flows from the primary heat exchanger to the secondary heat exchanger, where the temperature further decreases until the helium liquefies. Liquid helium flows from the secondary heat exchanger to the valve heat exchanger, where it cools the pipe clamp via heat conduction, thereby cooling the valve seat to a subcooled state. Record the temperature value measured by the second temperature sensor located on the pipe clamp. ; The heated liquid helium flows back from the valve heat exchanger to the secondary heat exchanger for further cooling and liquefaction. Step 3: Conduct a heat leakage performance test on the cryogenic valve to be tested, including: Measure the first heat loss along the path from the heat sink at a first temperature to the valve seat at a second temperature. ; Measure the second heat loss along the path from the valve support with a third temperature to the valve seat with a second temperature. Based on the first heat loss With the second heat loss To assess whether the heat leakage performance of the low-temperature valve under test meets the requirements; Step 4: After the test, helium flow to the helium recovery device; disassemble the cryogenic valve to be tested, replace it with another type of cryogenic valve and repeat steps 1 to 3.

Images