Vacuumizing resistance characteristic testing device and method for multi-layer heat insulation material of low-temperature storage tank

Abstract

The invention provides a vacuumizing resistance characteristic testing device and method for a multi-layer heat insulation material of a low-temperature storage tank. The vacuumizing resistance characteristic testing device comprises a cover plate and a shell, and an upper protection cavity, a testing cavity and a lower protection cavity are sequentially arranged in the shell from top to bottom; the outer surfaces of the upper protection cavity and the lower protection cavity are coated with multiple layers of heat insulation materials, the outer surfaces of the side wall and the bottom plate of the testing cavity are coated with multiple layers of heat insulation materials, a copper plate is arranged between a top plate of the testing cavity and the upper protection cavity, and the edge of the top plate of the testing cavity is connected with the edge of the copper plate through a silk screen. The outer sides of the silk screen and the copper plate are coated with multiple layers of heat insulation materials; one end of the rewarming pipeline is inserted into an area between the copper plate and the top plate of the test cavity, and the other end of the rewarming pipeline extends out of the cover plate and is connected with a second vacuum gauge. The pressure of the area between the copper plate and the testing cavity is measured through the second vacuum gauge, the interlayer pressure intensity of the heat insulation material is obtained, the second vacuum gauge does not need to be arranged in the multi-layer heat insulation material, and it is guaranteed that the heat insulation material is not damaged.

Description

Technical Field

[0001] The invention belongs to the field of cryogenic liquid storage and transportation, and in particular relates to a device and method for testing vacuum resistance characteristics of multi-layer thermal insulation materials of cryogenic storage tanks. Background Art

[0002] Heat leakage is inevitable during the storage and transportation of cryogenic liquids, which poses a huge challenge to the safety and economy of the cryogenic liquid storage process. The introduction of high vacuum multi-layer insulation technology has greatly reduced the heat leakage during the storage and transportation of cryogenic liquids. The core of this technology is to greatly weaken the thermal conductivity of gases by creating a high vacuum environment, introduce spacer materials with extremely low thermal conductivity to reduce solid thermal conductivity, and add radiation screens with extremely low emissivity to weaken radiation heat transfer. However, due to the influence of the interlayer resistance of the insulation material, the interlayer pressure level will be higher than the pressure at the rest of the tank interlayer. Normally, the interlayer pressure is better than 1.00×10 -2 Pa, in order to achieve a better insulation effect. Specifically, the wrapping and winding methods of multi-layer insulation materials, as well as the number of layers and layer density configuration, will affect the interlayer pressure. For example, the increase in the number of insulation layers will lead to an increase in vacuum resistance, making it more difficult to evacuate the gas between the layers, which in turn affects the insulation performance. At present, the measurement and analysis of the insulation performance of high-vacuum multi-layer insulation materials are mostly carried out under the condition of unknown interlayer pressure, which makes it difficult to conduct quantitative research.

[0003] In order to explore the vacuum resistance performance of multi-layer insulation materials and reveal the pressure level between layers, there are three main treatment methods in the existing literature.

[0004] One is to use the capillary mentioned in the Chinese patent application with publication number CN115238506A to indirectly measure the interlayer pressure. During the test, the capillary is placed between the layers of the multi-layer insulation material, and the pressure value at the top of the capillary is measured using an ionization gauge. However, on the one hand, the use of the capillary will damage the insulation material and affect the insulation performance; on the other hand, the working principle of the ionization gauge is to ionize the gas molecules into ions under the action of the electric field and the magnetic field. The interlayers of the multi-layer insulation material are rarefied gases, and the diameter of the capillary is extremely small (the diameter is 1 mm, and increasing the diameter will increase the parasitic heat leakage of the insulation material), resulting in a large deviation between the pressure level measured by the ionization gauge and the interlayer pressure.

[0005] The second method is to use a self-made interlayer pressure measurement device made by SLBapat and others. The device consists of a flexible disk installed in a multi-layer insulation material and a heating filament and a thermocouple on it. The heating filament and the thermocouple are used as thermocouple vacuum gauge elements for interlayer pressure measurement. However, on the one hand, the addition of the disk, thermocouple and heating filament will destroy the insulation material. On the other hand, due to the use of thermocouple sensitive elements, the minimum pressure measurement range is 133.32×10 -3Pa.

[0006] Finally, a vacuum resistance performance measurement device disclosed in a Chinese patent application with publication number CN108489854A is used. The device divides the inner liner into two parts, upper and lower, and places an ionization gauge in the area between the two inner liner to measure the pressure. However, the ionization gauge basically cannot work in an ultra-low temperature environment (the lowest normal temperature of a semiconductor element is usually 213.15K, and then as the temperature decreases, the performance of the semiconductor element gradually weakens until it fails). When liquid helium / liquid hydrogen / liquid nitrogen is placed in the inner liner, the temperature of the measuring end of the ionization gauge between the two inner liner can reach 4 K / 20 K / 77 K, and the vacuum degree obtained by the measurement at this time is greatly deviated from the actual result.

[0007] In summary, the existing devices for measuring the vacuum resistance characteristics of multi-layer insulation materials often have the problem of damaging the insulation materials, and there is a large deviation between the measurement results and the actual interlayer pressure. Summary of the invention

[0008] In order to solve the above problems of the prior art, the present invention provides a device and method for testing the vacuum resistance characteristics of multi-layer insulation materials of low-temperature storage tanks, which ensures that the insulation materials are not damaged and improves the measurement accuracy.

[0009] The present invention is achieved through the following technical solutions: In the first aspect, the present invention provides a device for testing the vacuum resistance characteristics of multi-layer thermal insulation materials of low-temperature storage tanks, comprising: a cover plate and an outer shell, the outer shell and the cover plate are sealed and connected to form a closed cavity, and an upper protection cavity, a test cavity and a lower protection cavity are sequentially arranged in the closed cavity from top to bottom; the side walls, bottom plate and top plate outer surfaces of the upper protection cavity and the lower protection cavity are coated with multi-layer thermal insulation materials, the side walls and bottom plate outer surfaces of the test cavity are coated with multi-layer thermal insulation materials, a copper plate is arranged parallel to the top plate of the test cavity and the upper protection cavity, the edge of the top plate of the test cavity is connected to the edge of the copper plate by a wire mesh, and the outer sides of the wire mesh and the copper plate are coated with multi-layer insulation materials. thermal material; the copper plate is connected to the bottom plate of the upper protection cavity through a copper column, and the outer surface of the copper column is covered with multiple layers of insulation material; the area between the upper protection cavity, the test cavity, the lower protection cavity and the outer shell is a vacuum interlayer, and a first vacuum gauge for measuring the pressure in the vacuum interlayer is arranged on the cover plate; a rewarming pipe is arranged on the cover plate, one end of the rewarming pipe is inserted into the area between the copper plate and the top plate of the test cavity, and the other end extends out of the cover plate and is connected to a second vacuum gauge; a vacuum pump is connected to the side wall of the outer shell; the upper protection cavity and the test cavity are both connected to a low-temperature liquid filling pipe and an emptying pipe, and the upper protection cavity is connected to the lower protection cavity through a pipe.

[0010] Preferably, the first vacuum gauge is a full-range gauge, and the second vacuum gauge is an ionization gauge.

[0011] Preferably, the top plate of the test chamber is made of polyester foam insulation material.

[0012] Preferably, a check valve is provided on one end of the exhaust pipe of the upper protection chamber extending out of the cover plate.

[0013] Preferably, a first gate valve and a mass flow meter are provided on one end of the exhaust pipe of the test chamber extending out of the cover plate, and the first gate valve is located between the mass flow meter and the cover plate.

[0014] Furthermore, an air cooling screen is provided in the multi-layer insulation material on the outer surface of the side wall of the test cavity.

[0015] Furthermore, a second gate valve is connected between the air-cooled screen and the exhaust pipe of the test chamber through a pipe, and the second gate valve is located in the shell. The air-cooled screen is also connected to the connecting pipe between the first gate valve and the mass flow meter through a pipe.

[0016] In a second aspect, the present invention provides a method for testing the vacuum resistance characteristics of multi-layer thermal insulation materials for cryogenic storage tanks, based on the vacuum resistance characteristics testing device for multi-layer thermal insulation materials for cryogenic storage tanks as described above, comprising: Step 1: Cover the side walls, bottom plate and top plate outer surfaces of the upper protection cavity and the lower protection cavity with multi-layer insulation materials according to the layer density configuration and layer number requirements, and cover the side walls and bottom plate of the test cavity and the outer surfaces of the wire mesh, copper plate and copper rod; Step 2: Place the upper protection cavity, the test cavity and the lower protection cavity in step 1 into the housing, and seal the cover plate to the housing; Step 3: Using a vacuum pump to evacuate the vacuum interlayer; Step 4: When the pressure values ​​of the first vacuum gauge and the second vacuum gauge are both lower than 0.01 Pa, inject cryogenic liquid into the upper protection chamber, the lower protection chamber and the test chamber through the cryogenic liquid filling pipeline; Step 5: Read the vacuum degrees of the first vacuum gauge and the second vacuum gauge, and calculate the vacuum resistance characteristics based on the read vacuum degrees.

[0017] Preferably, in the method for testing the vacuum resistance characteristics of multilayer insulation materials for cryogenic storage tanks, a first gate valve and a mass flow meter are provided on one end of the evacuation pipe of the test chamber extending out of the cover plate; In step 5: When the mass flow meter reading is stable, read the vacuum degree of the full range gauge and the ionization gauge.

[0018] Furthermore, in the test method for vacuum resistance characteristics of multi-layer insulation materials of low-temperature storage tanks, an air-cooling screen is provided in the multi-layer insulation material on the outer surface of the side wall of the test chamber, and a second gate valve is connected between one end of the air-cooling screen extending out of the multi-layer insulation material and the emptying pipe of the test chamber, the second gate valve is located in the housing, and the air-cooling screen is also connected to the connecting pipe between the first gate valve and the mass flow meter through a pipe; In step five: close the second gate valve, open the first gate valve, and when the mass flow meter reading is stable, read the vacuum degree of the full-scale gauge and the ionization gauge; or close the first gate valve, open the second gate valve, and when the mass flow meter reading is stable, read the vacuum degree of the full-scale gauge and the ionization gauge.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The method for measuring the interlayer pressure of the insulation material by the vacuum resistance characteristic testing device for multilayer insulation materials of low-temperature storage tanks of the present invention is: a specific number of multilayer insulation materials are coated on the test cavity, and then the pressure of the area between the copper plate and the test cavity is measured by a second vacuum gauge, so as to obtain the interlayer pressure of the insulation material with the corresponding number of layers; affected by the gas flow resistance between the multilayer insulation materials, there is a difference between the interlayer pressure of the insulation material and the pressure in the vacuum interlayer, and the difference between the two is the vacuum resistance performance of the multilayer insulation material. The second vacuum gauge of the present invention measures the pressure of the area between the copper plate and the test cavity, and there is no need to set the second vacuum gauge in the multilayer insulation material, thereby ensuring that the insulation material is not damaged. The second vacuum gauge of the present invention is connected to the area between the copper plate and the top plate of the test chamber through a reset pipe. The temperature recovery pipe makes the temperature of the measuring end of the second vacuum gauge higher than 263.15 K, so that the second vacuum gauge does not need to be exposed to low temperature, avoiding the increase of measurement error caused by the weakening of semiconductor performance in low temperature environment, and improving the measurement accuracy. It can realize the measurement of the vacuum resistance performance of multi-layer insulation materials of low-temperature storage tanks in any temperature zone (such as liquid helium temperature is 4.2 K, liquid hydrogen temperature is 20 K, and liquid nitrogen temperature is 77 K). In addition, compared with the combination of filament and thermocouple to measure interlayer pressure, the device uses a vacuum gauge to measure interlayer pressure, and the measurement range can be expanded to 1×10 -5 Pa, and the measurement accuracy is higher.

[0020] Furthermore, the first vacuum gauge of the present invention adopts a full-range gauge, and the second vacuum gauge adopts an ionization gauge. Because during the vacuuming process, the vacuum degree varies in a relatively large range, and the full-range gauge has a large range, it can be used to measure the vacuum degree in the vacuum interlayer and guide the opening and closing of the vacuum pump. In the steady state, the interlayer pressure is in a high vacuum state, and the use of an ionization gauge can meet the high vacuum measurement requirements.

[0021] Furthermore, in order to avoid heat leakage in the test cavity due to temperature difference between the copper plate and the test cavity, the top plate of the test cavity is made of polyester foam insulation material, which can play an insulating role, thereby avoiding heat exchange between the test cavity and the copper plate.

[0022] Furthermore, a check valve is provided on one end of the exhaust pipe of the upper protection chamber extending out of the cover plate of the present invention, and the check valve is used to control the exhaust pressure of the upper protection chamber to avoid danger caused by excessive pressure in the upper protection chamber.

[0023] Furthermore, a first gate valve and a mass flow meter are provided on one end of the exhaust pipe of the test chamber extending out of the cover plate. The mass flow meter is used to measure the steam exhaust mass flow rate of the test chamber, and the heat leakage of the test chamber can be calculated based on the steam exhaust mass flow rate.

[0024] Furthermore, an air-cooled screen is provided in the multi-layer insulation material on the outer surface of the side wall of the test chamber. A second gate valve is connected between the air-cooled screen and the exhaust pipe of the test chamber through a pipeline. The second gate valve is located in the shell. The first gate valve and the second gate valve can control the exhaust flow path of the test chamber. There are two options for exhausting the evaporated gas from the test chamber. One is to directly lead it out of the shell through the pipeline through the first gate valve, and the other is to introduce it into the air-cooled screen through the pipeline through the second gate valve, and then lead it out of the shell through the air-cooled screen. When the gas discharged from the test chamber enters the air-cooled screen through the pipeline, the temperature of the evaporated gas is relatively low, so it can play a cooling role in the air-cooled screen, that is, the cold energy is recycled. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a structural schematic diagram of the vacuum resistance characteristic measuring device of the present invention.

[0027] In the figure: 1. First vacuum gauge; 2. Second vacuum gauge; 3. Retemperature pipe; 4. Check valve; 5. First gate valve; 6. Mass flow meter; 7. Cover plate; 8. Vacuum pump; 9. Upper protection chamber; 10. Second gate valve; 11. Copper rod; 12. Copper plate; 13. Silk screen; 14. Polyester foam insulation material; 15. Air cooling screen; 16. Test chamber; 17. Lower protection chamber; 18. Multi-layer insulation material; 19. Shell. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0029] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0030] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0031] In addition, it should be noted that the terms "first", "second", etc. of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. The orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements.

[0032] like Figure 1 As shown, in the embodiment of the present invention, the vacuum resistance characteristics testing device of the multi-layer thermal insulation material of the low-temperature storage tank includes: a first vacuum gauge 1, a second vacuum gauge 2, a retemperature pipeline 3, a check valve 4, a first gate valve 5, a mass flow meter 6, a cover plate 7, a vacuum pump 8, an upper protection chamber 9, a second gate valve 10, a copper rod 11, a copper plate 12, a wire mesh 13, an air-cooled shield 15, a test chamber 16, a lower protection chamber 17, a multi-layer thermal insulation material 18 and a shell 19.

[0033] The vacuum pump 8 is installed on the side wall of the outer shell 19; the outer shell 19 is sealed with the cover plate 7 to form a closed cavity, and the upper protective cavity 9, the test cavity 16, and the lower protective cavity 17 are all arranged in the closed cavity. The area between the upper protective cavity 9, the test cavity 16, the lower protective cavity 17 and the outer shell 19 is a vacuum interlayer, and the vacuum pump 8 is used to evacuate the vacuum interlayer. The cover plate 7 is provided with a first vacuum gauge 1 for measuring the pressure in the vacuum interlayer. The upper protective cavity 9 and the test cavity 16 are both connected with a low-temperature liquid filling pipeline and an emptying pipeline, and the upper protective cavity 9 and the lower protective cavity 17 are connected through a pipeline. The present invention respectively arranges an upper protective cavity 9 and a lower protective cavity 17 above and below the test cavity 16. When in use, the low-temperature liquid injected into the upper protective cavity 9 and the lower protective cavity 17 can play a role in reducing the heat leakage of the test cavity 16, so that the test can be carried out normally.

[0034] The outer surfaces of the side walls, bottom plates and top plates of the upper protection chamber 9 and the lower protection chamber 17 are all coated with multi-layer insulation materials 18, and the outer surfaces of the side walls and bottom plates of the test chamber 16 are all coated with multi-layer insulation materials 18. A copper plate 12 is arranged parallel to the top plate of the test chamber 16 and the upper protection chamber 9. The edge of the top plate of the test chamber 16 is connected to the edge of the copper plate 12 by a wire mesh 13. The outer surfaces of the wire mesh 13 and the copper plate 12 are all coated with multi-layer insulation materials 18. The copper plate 12 is connected to the bottom plate of the upper protection chamber 9 by a copper column 11. The outer surface of the side wall of the copper rod 11 is coated with multi-layer insulation materials 18. A rewarming pipe 3 is arranged on the cover plate 7. One end of the rewarming pipe 3 is inserted into the area between the copper plate 12 and the top plate of the test chamber 16, and the other end extends out of the cover plate 7 and is connected to the second vacuum gauge 2. The second vacuum gauge 2 is used to measure the pressure in the area between the copper plate 12 and the top plate of the test chamber 16.

[0035] The number of copper rods 11 between the copper plate 12 and the upper protective cavity 9 is sufficient (greater than 4) to ensure that the temperature difference between the copper plate 12 and the upper protective cavity 9 is less than 2 K. In order to avoid the temperature difference between the copper plate 12 and the test cavity 16 causing heat leakage of the test cavity 16, the top plate of the test cavity 16 is made of polyester foam insulation material 14, which can play a role of insulation, thereby avoiding heat exchange between the test cavity 16 and the copper plate 12.

[0036] The present invention provides a copper plate 12 and connects it to the upper protection chamber 9 through a copper column 11, so that the temperature of the copper plate 12 is substantially consistent with the temperature in the upper protection chamber 9, so that the copper plate 12 can maintain a temperature substantially consistent with the test chamber 16, thereby avoiding heat leakage of the test chamber 16. When the vacuum pump 8 is used for evacuation, the pressure in the area between the copper plate 12 and the top plate of the test chamber 16 is the same as the pressure in the multi-layer insulation material 18 outside the area, so that the pressure in the area between the copper plate 12 and the top plate of the test chamber 16 can be measured by the second vacuum gauge 2 to reflect the pressure in the multi-layer insulation material 18, and the difference between the pressure and the pressure in the vacuum interlayer is the vacuum resistance of the multi-layer insulation material 18.

[0037] The present invention does not need to set the second vacuum gauge 2 in the multi-layer insulation material 18, so that the multi-layer insulation material 18 will not be damaged. In addition, the second vacuum gauge 2 of the present invention is connected to the area between the copper plate 12 and the top plate of the test chamber 16 through the reset pipe 3. The rewarming pipe 3 is long enough (greater than 0.1 m) so that the temperature of the measuring end of the second vacuum gauge 2 is higher than 263.15 K. Therefore, the second vacuum gauge 2 does not need to be exposed to low temperature, which avoids the increase of measurement error caused by the weakening of semiconductor performance in a low-temperature environment, and can realize the measurement of the vacuum resistance performance of the multi-layer insulation material of a cryogenic storage tank in any temperature zone (such as liquid helium temperature of 4.2 K, liquid hydrogen temperature of 20 K, and liquid nitrogen temperature of 77 K).

[0038] The end of the exhaust pipe of the upper protection chamber 9 extending out of the cover plate 7 is provided with a check valve 4, because the cryogenic liquid in the upper protection chamber 9 may evaporate, and the evaporated gas needs to be discharged through the exhaust pipe. The check valve 4 is used to control the exhaust pressure of the upper protection chamber 9. When the check valve 4 is opened, the pressure in the upper protection chamber 9 is greater than 0.103 MPa.

[0039] The first gate valve 5 and the mass flow meter 6 are arranged on one end of the exhaust pipe of the test chamber 16 extending out of the cover plate 7, and the first gate valve 5 is located between the mass flow meter 6 and the cover plate 7. An air cooling screen 15 is arranged in the multi-layer insulation material 18 on the outer surface of the side wall of the test chamber 16, and the air cooling screen 15 is connected to the exhaust pipe of the test chamber 16 through a pipeline with a second gate valve 10, and the second gate valve 10 is located in the housing 19, and the air cooling screen 15 is also connected to the connecting pipe between the first gate valve 5 and the mass flow meter 6 through a pipeline.

[0040] The mass flow meter 6 is used to measure the steam discharge mass flow rate of the test chamber 16. The heat leakage of the test chamber 16 can be calculated based on the steam discharge mass flow rate. The first gate valve 5 and the second gate valve 10 are used to control the discharge flow path of the test chamber 16. There are two options for the discharge of the evaporated gas from the test chamber 16. One is to directly lead it out of the shell through the pipeline through the first gate valve 5, and the other is to introduce it into the air-cooled screen 15 through the pipeline through the second gate valve 10, and then lead it out of the shell from the air-cooled screen 15. When the gas discharged from the test chamber 16 enters the air-cooled screen 15 through the pipeline, the pipeline should be connected from the test chamber 16 to the area between the copper plate 12 and the upper protective chamber 9 to avoid damage to the wire mesh 13 and the multi-layer insulation material 18 of the side wall. When the evaporated gas from the test chamber 16 is introduced into the air-cooled screen 15 through the second gate valve 10, due to the relatively low temperature of the evaporated gas, it can play a cooling role in the air-cooled screen 15, that is, the cold energy is recycled.

[0041] In the embodiment of the present invention, the first vacuum gauge 1 is preferably a full-range gauge, and the second vacuum gauge 2 is preferably an ionization gauge. Because the vacuum degree varies widely during the vacuum pumping process, the full-range gauge has a large range and can be used to measure the vacuum degree in the vacuum interlayer and guide the opening and closing of the vacuum pump. In the steady state, the interlayer pressure is in a high vacuum state, and the use of an ionization gauge can meet the high vacuum measurement requirements.

[0042] In the embodiment of the present invention, the vacuum pump 8 is a molecular pump unit.

[0043] The method for testing the vacuum resistance characteristics of the multilayer insulation material of a cryogenic storage tank of the present invention comprises the following steps: Step 1: Coat the side walls, bottom plate and top plate outer surfaces of the upper protection cavity 9 and the lower protection cavity 17 with the multi-layer insulation material 18 according to the layer density configuration and layer number requirements, and coat the side walls and bottom plate of the test cavity 16 and the outer surfaces of the wire mesh 13, the copper plate 12 and the copper rod 11; Step 2: Place the upper protection chamber 9, the test chamber 16 and the lower protection chamber 17 in step 1 into the housing 19, and then seal the cover plate 7 and the housing 19 through a flange; Step 3: Use the vacuum pump 8 to evacuate the vacuum interlayer. Due to the resistance of gas flow between the layers of the multi-layer insulation material 18, there is a difference in the vacuum degree between the area between the copper plate 12 and the test cavity 16 and the vacuum interlayer; Step 4: When the pressure values ​​of the first vacuum gauge 1 and the second vacuum gauge 2 in step 3 are both lower than 0.01 Pa, inject cryogenic liquid into the upper protection chamber 9, the lower protection chamber 17 and the test chamber 16; Step 5: When the mass flow meter 6 reading is stable, read the vacuum degree of the first vacuum gauge 1 and the second vacuum gauge 2 to obtain the vacuum resistance characteristics of the insulation material under a specific layer density configuration, number of layers and winding method.

Claims

1. A device for testing the vacuum resistance characteristics of multi-layer insulation materials for cryogenic storage tanks, characterized in that: include: A cover plate (7) and an outer shell (19), the outer shell (19) and the cover plate (7) are sealed and connected to form a closed cavity, wherein an upper protective cavity (9), a test cavity (16) and a lower protective cavity (17) are sequentially arranged in the closed cavity from top to bottom; the side walls, bottom plates and outer surfaces of the top plates of the upper protective cavity (9) and the lower protective cavity (17) are all coated with multiple layers of thermal insulation material (18), the side walls and outer surfaces of the bottom plates of the test cavity (16) are all coated with multiple layers of thermal insulation material (18), a copper plate (12) is arranged parallel to the top plate of the test cavity (16) and the upper protective cavity (9), the edge of the top plate of the test cavity (16) and the edge of the copper plate (12) are connected via a wire mesh (13), and the outer sides of the wire mesh (13) and the copper plate (12) are both coated with multiple layers of thermal insulation material (18); the copper plate (12) is connected to the upper protective cavity (9) via a copper column (11). The bottom plate of the protective cavity (9) is connected, and the outer surface of the copper column (11) is coated with multiple layers of insulation material (18); the area between the upper protective cavity (9), the test cavity (16) and the lower protective cavity (17) and the outer shell (19) is a vacuum interlayer, and a first vacuum gauge (1) for measuring the pressure in the vacuum interlayer is arranged on the cover plate (7); a rewarming pipe (3) is arranged on the cover plate (7), one end of the rewarming pipe (3) is inserted into the area between the copper plate (12) and the top plate of the test cavity (16), and the other end extends out of the cover plate (7) and is connected to a second vacuum gauge (2); a vacuum pump (8) is connected to the side wall of the outer shell (19); the upper protective cavity (9) and the test cavity (16) are both connected to a cryogenic liquid filling pipe and an emptying pipe, and the upper protective cavity (9) and the lower protective cavity (17) are connected through a pipe.

2. The device for testing vacuum resistance characteristics of multi-layer insulation materials for cryogenic storage tanks according to claim 1 is characterized in that: The first vacuum gauge (1) is a full-range gauge, and the second vacuum gauge (2) is an ionization gauge.

3. The vacuum resistance characteristics testing device for multi-layer insulation materials of cryogenic storage tanks according to claim 1 is characterized in that: The top plate of the test chamber (16) is made of polyester foam thermal insulation material (14).

4. The device for testing vacuum resistance characteristics of multi-layer insulation materials for cryogenic storage tanks according to claim 1 is characterized in that: A check valve (4) is provided on one end of the exhaust pipe of the upper protective chamber (9) extending outside the cover plate (7).

5. The vacuum resistance characteristics testing device for multi-layer insulation materials of cryogenic storage tanks according to claim 1 is characterized in that: A first gate valve (5) and a mass flow meter (6) are provided on one end of the exhaust pipe of the test chamber (16) extending outside the cover plate (7); the first gate valve (5) is located between the mass flow meter (6) and the cover plate (7).

6. The device for testing vacuum resistance characteristics of multi-layer insulation materials for cryogenic storage tanks according to claim 5 is characterized in that: An air cooling screen (15) is arranged in the multi-layer heat insulating material (18) on the outer surface of the side wall of the test chamber (16).

7. The device for testing vacuum resistance characteristics of multi-layer insulation materials for cryogenic storage tanks according to claim 6 is characterized in that: A second gate valve (10) is connected between the air-cooling shield (15) and an exhaust pipe of the test chamber (16) through a pipe, and the second gate valve (10) is located in the housing (19). The air-cooling shield (15) is also connected to a connecting pipe between the first gate valve (5) and the mass flow meter (6) through a pipe.

8. A method for testing the vacuum resistance characteristics of multilayer insulation materials for cryogenic storage tanks, characterized in that: The device for testing vacuum resistance characteristics of multilayer thermal insulation materials for cryogenic storage tanks according to any one of claims 1 to 8 comprises: Step 1: coating the multilayer insulation material (18) on the side walls, bottom plate and top plate outer surfaces of the upper protection cavity (9) and the lower protection cavity (17) according to the layer density configuration and layer number requirements, and coating the side walls and bottom plate of the test cavity (16) and the outer surfaces of the wire mesh (13), the copper plate (12) and the copper rod (11); Step 2: placing the upper protection chamber (9), the test chamber (16) and the lower protection chamber (17) in step 1 into the housing (19), and sealingly connecting the cover plate (7) to the housing (19); Step 3: Using a vacuum pump (8) to evacuate the vacuum interlayer; Step 4: When the pressure values ​​of the first vacuum gauge (1) and the second vacuum gauge (2) are both lower than 0.01 Pa, inject cryogenic liquid into the upper protection chamber (9), the lower protection chamber (17) and the test chamber (16) through the cryogenic liquid filling pipeline; Step 5: Read the vacuum degrees of the first vacuum gauge (1) and the second vacuum gauge (2), and calculate the vacuum resistance characteristics based on the read vacuum degrees.

9. The method for testing vacuum resistance characteristics of multilayer insulation materials for cryogenic storage tanks according to claim 8, characterized in that: A first gate valve (5) and a mass flow meter (6) are provided on one end of the exhaust pipe of the test chamber (16) extending outside the cover plate (7); In step 5: When the mass flow meter (6) reading is stable, read the vacuum degree of the full range gauge (1) and the ionization gauge (2).

10. The method for testing vacuum resistance characteristics of multilayer insulation materials for cryogenic storage tanks according to claim 9, characterized in that: An air cooling screen (15) is arranged in the multi-layer insulation material (18) on the outer surface of the side wall of the test chamber (16); a second gate valve (10) is connected between one end of the air cooling screen (15) extending out of the multi-layer insulation material (18) and an exhaust pipe of the test chamber (16); the second gate valve (10) is located in the housing (19); and the air cooling screen (15) is also connected to a connecting pipe between the first gate valve (5) and the mass flow meter (6) via a pipe; In step 5: the second gate valve (10) is closed, the first gate valve (5) is opened, and when the reading of the mass flow meter (6) is stable, the vacuum degree of the full-scale gauge (1) and the ionization gauge (2) is read; or, the first gate valve (5) is closed, the second gate valve (10) is opened, and when the reading of the mass flow meter (6) is stable, the vacuum degree of the full-scale gauge (1) and the ionization gauge (2) is read.

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