Safety device of low-temperature liquid storage tank

Abstract

The invention provides a low-temperature liquid storage tank safety device. The low-temperature liquid storage tank safety device comprises a first safety valve, a partition plate, a liquid guide pipe, an upper cavity heat-conducting fin and a lower cavity heat-conducting fin. The partition plate transversely partitions the upper part of the tank body and divides an inner cavity of the tank body into an upper cavity body and a lower cavity body; the first safety valve is arranged between the top of the upper cavity and the outside; the liquid guide pipe is communicated between the upper cavity and the lower cavity, the upper end of the liquid guide pipe is connected with the partition plate, and the lower end of the liquid guide pipe extends to the bottom of the lower cavity; an upper cavity heat-conducting fin is vertically arranged on the upper surface of the partition plate, and a lower cavity heat-conducting fin is vertically arranged on the lower surface of the partition plate. The device overcomes the defect that the waste rate of effective resources is high due to the fact that high-pressure gas accumulated at the top of the tank body is directly discharged without any treatment of an existing safety device of the low-temperature liquid storage tank.

Description

Technical Field

[0001] The invention relates to the technical field of cryogenic liquid storage, and in particular to a safety device for a cryogenic liquid storage tank. Background Art

[0002] A cryogenic liquid storage tank is a tank used to store cryogenic liquids, such as liquid helium, liquid hydrogen, liquid nitrogen, liquefied natural gas and other cryogenic liquids. It is generally a double-layer insulated storage tank. The cryogenic liquid is stored in the inner tank. An interlayer is provided between the outer shell and the inner tank. The interlayer is insulated by vacuuming or filling with insulation materials. Although the cryogenic liquid storage tank has relevant insulation measures, heat leakage is still inevitable during the storage process. The heat leaked into the tank will heat the cryogenic liquid and evaporate it into a gaseous state. Because the transition process from the liquid phase to the gas phase of an object will cause its volume to expand extremely. If the gas phase space in the tank is relatively small, the evaporated gas will be completely filled in the narrow gas phase space, so that the gas in the gas phase space is continuously compressed and then the pressure value is increased until the pressure limit of the tank is reached, causing a safety accident. Therefore, in order to ensure the safety of the tank, the existing cryogenic liquid storage tank will be equipped with a safety valve in the gas phase space area in the tank. Once the gas pressure reaches the warning value, the high-pressure gas will be released to reduce the pressure in the tank. However, this practice of directly discharging high-pressure gas without any treatment has caused a waste of effective resources to a certain extent, especially rare gas resources such as liquid argon, which has a very high production cost and discharging it will cause great economic losses. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the safety device of the existing cryogenic liquid storage tank directly discharges the high-pressure gas accumulated on the top of the tank body without any treatment, resulting in a high waste rate of effective resources.

[0004] In order to solve the above technical problems, the present application provides a low-temperature liquid storage tank safety device for ensuring the pressure safety of the tank body, which includes a first safety valve, a partition, a liquid guide tube, an upper cavity heat conductive plate and a lower cavity heat conductive plate; the partition is horizontally arranged above the tank body, dividing the inner cavity of the tank body into an upper cavity and a lower cavity; the first safety valve is arranged between the top of the upper cavity and the outside world; the liquid guide tube is connected between the upper cavity and the lower cavity, the upper end of the liquid guide tube is connected to the partition, and the lower end of the liquid guide tube extends to the bottom of the lower cavity; an upper cavity heat conductive plate is vertically arranged on the upper surface of the partition, and a lower cavity heat conductive plate is vertically arranged on the lower surface of the partition.

[0005] Furthermore, it also includes a second safety valve, which is arranged between the top of the lower cavity and the outside.

[0006] Furthermore, the release pressure value of the second safety valve is higher than the release pressure value of the first safety valve, and the second safety valve is communicatively connected with a fault alarm, which is triggered when the second safety valve is opened.

[0007] Furthermore, the upper cavity is filled with nitrogen.

[0008] Furthermore, it also includes a liquid storage cylinder, which is connected to the partition through the bottom of the liquid storage cylinder is a closed structure and extends into the lower cavity, the top of the liquid storage cylinder is a flat opening, and the top of the liquid storage cylinder protrudes from the upper surface of the partition.

[0009] Furthermore, an electrically controlled stop valve is arranged at the bottom end of the liquid storage cylinder, and the electrically controlled stop valve is connected between the inner cavity of the liquid storage cylinder and the lower cavity.

[0010] Furthermore, the bottom end of the liquid storage cylinder extends to the bottom of the lower cavity, and a liquid storage cylinder heat conducting sheet is arranged at the bottom of the liquid storage cylinder.

[0011] Furthermore, the liquid guiding tube is located at the center of the partition, and the upper cavity heat conducting sheet is radially arranged around the liquid guiding tube.

[0012] Furthermore, the lower cavity heat conducting sheet is radially arranged around the liquid guiding tube, the outer ends of the upper cavity heat conducting sheet and the lower cavity heat conducting sheet are connected to the side wall of the tank body, and a heat conducting sheet gap is formed between the inner ends of the upper cavity heat conducting sheet and the inner ends of the lower cavity heat conducting sheet.

[0013] Furthermore, the lower cavity heat conducting sheet includes an air chamber heat conducting sheet and a tank wall heat conducting sheet connected into an inverted L-shaped structure.

[0014] By adopting the above technical solution, the present invention has the following technical effects: The low-temperature liquid storage tank safety device provided by the present invention divides the inner cavity of the tank body into an upper cavity and a lower cavity connected by the liquid conduit by arranging a partition and a liquid conduit. Because the lower end of the liquid conduit extends to the bottom of the lower cavity, when liquid is input into the lower cavity, after the liquid level exceeds the lower end of the liquid conduit, the gas in the upper cavity and the liquid conduit has nowhere to be released, thereby forming an airtight cavity. For low-temperature liquid storage tanks, pressure danger mainly occurs when the liquid is full and the gas phase space is small, because compared with the situation where there is less liquid and the gas phase space is larger, although the same heat leakage causes the same liquid to evaporate, the evaporated gas is filled in gas phase spaces of different sizes, which will cause several times the pressure difference. The above-mentioned airtight cavity has the necessity of formation, which ensures that there is an appropriate gas phase space in the tank body, thereby preventing the operator from overfilling the liquid due to negligence of the retention of the gas phase space, causing related safety hazards. In addition, when the cryogenic liquid is stored for a long time and gas appears in the lower cavity due to heat leakage, as the gas gradually increases, the gas in the lower cavity will push the gas in the above-mentioned airtight cavity, thereby compressing and pressurizing the gas in the upper cavity. Because the diameter of the liquid guide tube is much smaller than the inner diameter of the lower cavity, the liquid in the lower cavity will quickly fill the liquid guide tube under the pressure of the upper cavity until it flows into the upper cavity. Because the fluid has a temperature stratification phenomenon, the fluid in the lower layer is usually the lowest temperature, so the cryogenic liquid sucked from the lower end of the liquid guide tube is the lowest temperature in the entire tank. When this lowest temperature liquid is sucked into the upper cavity above, it is spread on the partition. Under the joint action of the upper cavity heat conductive sheet and the lower cavity heat conductive sheet connected to the partition, the gas in the upper and lower cavities will be cooled, so that the gas in the gas phase space in the tank is cooled and contracted, and even condensed back to the liquid phase, and finally the pressure in the tank is reduced. In this way, the high-pressure gas in the tank will be cooled before being released by the safety valve, and some of the gas may also condense back to the liquid state, so that effective resources can be recovered and the amount of gas released under normal conditions can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic front cross-sectional view of the structure of an embodiment of the present invention; Figure 2 for Figure 1 Cross-sectional view at AA in the middle.

[0017] Description of reference numerals: 1-exhaust valve, 2-second safety valve, 3-fault alarm, 4-first safety valve, 5-upper cavity, 6-partition, 7-liquid guide tube, 8-liquid storage cylinder, 9-liquid storage cylinder thermal conductive plate, 10-electrically controlled stop valve, 11-liquid outlet valve, 12-liquid inlet valve, 13-tank body, 14-lower cavity, 15-tank wall thermal conductive plate, 16-air chamber thermal conductive plate, 17-lower cavity thermal conductive plate, 18-upper cavity thermal conductive plate, 19-thermal conductive plate gap, 20-tank top through pipe. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted in the description of the present invention that the coordinate system used in this specification when describing the orientation is determined by the posture of the corresponding main view, and the naming of the observation angle of the corresponding view is also based on this. Therefore, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. in this specification indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 on the present invention.

[0020] In the description of the present invention, it should be noted that, 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, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] This embodiment provides a cryogenic liquid storage tank safety device for ensuring the pressure safety of the tank body 13. In one embodiment, Figure 1 and 2As shown, it includes a first safety valve 4, a partition 6, a liquid guide tube 7, an upper cavity heat conductive sheet 18 and a lower cavity heat conductive sheet 17. The partition 6 is horizontally spaced above the tank body 13, dividing the inner cavity of the tank body 13 into an upper cavity 5 and a lower cavity 14; the first safety valve 4 is arranged between the top of the upper cavity 5 and the outside; the liquid guide tube 7 is connected between the upper cavity 5 and the lower cavity 14, the upper end of the liquid guide tube 7 is connected to the partition 6, and the lower end of the liquid guide tube 7 extends to the bottom of the lower cavity 14; the upper cavity heat conductive sheet 18 is vertically arranged on the upper surface of the partition 6, and the lower cavity heat conductive sheet 17 is vertically arranged on the lower surface of the partition 6.

[0023] Because the device divides the tank body 13 into an upper cavity 5 and a lower cavity 14, when in use, the lower cavity 14 serves as a conventional storage tank capacity for storing cryogenic liquids, so a liquid outlet valve 11 and a liquid inlet valve 12, as well as related valves such as an exhaust valve 1 for exhausting gas during filling, can be provided on the lower cavity 14. When designing the capacity allocation of the upper cavity 5 and the lower cavity 14 of the storage tank, the position of the partition 6 can be set with reference to the minimum related requirements for the gas phase space under the specifications of the storage tank, so that the upper cavity 5 is roughly equivalent to the volume of the gas phase space, and the lower cavity 14 can be used as the liquid phase space for storing all the cryogenic liquids.

[0024] This safety device divides the inner cavity of the tank body 13 into an upper cavity 5 and a lower cavity 14 connected by the liquid conduit 7 by setting a partition 6 and a liquid conduit 7. Because the lower end of the liquid conduit 7 extends to the bottom of the lower cavity 14, when liquid is input into the lower cavity 14, after the liquid level exceeds the lower end of the liquid conduit 7, the gas in the upper cavity 5 and the liquid conduit 7 has nowhere to be released, thus forming an airtight cavity. For low-temperature liquid storage tanks, pressure danger mainly occurs when the liquid is full and the gas phase space is small, because compared with the situation where the liquid is less and the gas phase space is larger, the same heat leakage causes the same liquid to evaporate, but the evaporated gas is filled in gas phase spaces of different sizes, which will cause several times the pressure difference. The above-mentioned airtight cavity has the necessity of formation, which ensures that there is an appropriate gas phase space in the tank body 13, thereby preventing the operator from overfilling the liquid due to negligence of the retention of the gas phase space, causing related safety hazards.

[0025] In addition, when the low-temperature liquid is stored for a long time and gas appears in the lower cavity 14 due to heat leakage, as the gas gradually increases, the gas in the lower cavity 14 will push the gas in the above-mentioned airtight cavity, thereby compressing and pressurizing the gas in the upper cavity 5. Because the diameter of the liquid conduit 7 is much smaller than the inner diameter of the lower cavity 14, the liquid in the lower cavity 14 will quickly fill the liquid conduit 7 under the pressure of the upper cavity 5 until it flows into the upper cavity 5. Since the fluid has a temperature stratification phenomenon, the fluid in the lower layer is usually the lowest temperature, so the low-temperature liquid sucked from the lower end of the liquid conduit 7 is the lowest temperature in the entire tank. When this lowest temperature liquid is sucked into the upper cavity 5 above, it will be spread on the partition 6. Under the joint action of the upper cavity heat conductive sheet 18 and the lower cavity heat conductive sheet 17 connected to the partition 6, the gas in the upper and lower cavities will be cooled, so that the gas in the gas phase space in the tank will be cooled and contracted, and even condensed back to the liquid phase, and finally reduce the pressure in the tank. In this way, the high-pressure gas in the tank will be cooled before being released by the safety valve, and part of the gas may condense back into liquid, thereby recovering effective resources and reducing the amount of gas released under normal conditions.

[0026] Based on the above implementation, in a preferred implementation, Figure 1 As shown, it also includes a second safety valve 2, which is arranged between the top of the lower cavity 14 and the outside. When the liquid guide tube 7 is in use, because it needs to be filled with liquid quickly, its diameter should be as small as possible. In some cases, a small-diameter guide tube may be accidentally blocked, resulting in the upper and lower compartments being unable to communicate. After the above-mentioned second safety valve 2 is set, it can still ensure that the pressure in the tank does not exceed the standard when the accident occurs. In addition, the second safety valve 2 can share the same tank top through pipe 20 with the exhaust valve 1, so as to reduce the reduction of thermal insulation performance caused by the tank body 13 being penetrated by the pipeline.

[0027] Based on the above implementation, in a preferred implementation, Figure 1 As shown, the release pressure value of the second safety valve 2 is higher than the release pressure value of the first safety valve 4. The second safety valve 2 is connected to the fault alarm 3, and the fault alarm 3 is triggered when the second safety valve 2 is opened. Because the pressure danger of the storage tank often occurs when the tank is full of liquid and less gas. When the liquid is full, the air pressure in the upper and lower compartments is roughly the same, and setting the release pressure value of the first safety valve 4 to a lower value can make the first safety valve 4 a pressure release channel under normal conditions. However, if the second safety valve 2 with a higher setting value is activated, it usually means that the upper and lower compartments cannot be connected, that is, the liquid guide tube 7 is blocked, and the fault alarm 3 is triggered after the second safety valve 2 is activated, so that the maintenance personnel can be informed of the existence of the fault and carry out maintenance in time.

[0028] Based on the above embodiment, in a preferred embodiment, nitrogen is filled in the upper cavity 5. The filled pipeline can share the relevant pipeline of the first safety valve 4 to reduce the degradation of the thermal insulation performance after the tank body 13 is penetrated. In the case where the purity requirement of the cryogenic liquid is relatively low, low-cost nitrogen can be used to fill the upper cavity 5, because liquid nitrogen has a lower boiling point than liquid argon, and nitrogen can also be gaseous when argon is liquid, and nitrogen has a lower density than argon and will float on argon. Therefore, even if it is necessary to release the gas, the first safety valve 4 will release nitrogen first, thereby retaining the expensive argon.

[0029] Based on the above implementation, in a preferred implementation, Figure 1 As shown, it also includes a liquid storage cylinder 8, which is connected to the partition 6 through the bottom of the liquid storage cylinder 8 is a closed structure and extends into the lower cavity 14, and the top of the liquid storage cylinder 8 is a flat opening, and the top of the liquid storage cylinder 8 protrudes from the upper surface of the partition 6. When too much liquid is sucked into the upper cavity 5, the temperature of the low-temperature liquid sucked earlier will rise after heat conduction. If it remains in the upper cavity 5, it will produce heat exchange with the low-temperature liquid sucked later, thereby reducing the cooling effect of the low-temperature liquid sucked later. After the liquid storage cylinder 8 with the top protruding from the partition 6 is set, due to the temperature stratification of the liquid, the hotter liquid sucked earlier will float on the colder liquid sucked later, until it overflows the top of the liquid storage cylinder 8, and then is collected in the liquid storage cylinder 8, reducing the cold energy loss of the hot and cold liquids in the upper cavity 5.

[0030] Based on the above implementation, in a preferred implementation, Figure 1 As shown, an electrically controlled stop valve 10 is provided at the bottom end of the liquid storage cylinder 8, and the electrically controlled stop valve 10 is connected between the inner cavity of the liquid storage cylinder 8 and the lower cavity 14. After long-term use, the liquid storage cylinder 8 will inevitably contain liquid, and if it is filled, it will lose its function, so it is necessary to set a drainage channel. After the above-mentioned electrically controlled stop valve 10 is set, the liquid storage cylinder 8 is connected with the lower cavity 14. After the liquid in the tank is discharged to below the bottom surface of the liquid storage cylinder 8, the valve can be opened to release the stored liquid. The reason why an electrically controlled valve is used for communication in the tank, rather than setting a drainage port that passes through the tank body 13 in the liquid storage cylinder 8, is because the wires are easy to route and have a small cross-section, so it is convenient to use other channels to pass through the tank body 13, and even if they pass directly through the tank body 13, it will not cause too much decline in thermal insulation performance. In addition, this arrangement creates a connecting path between the upper and lower compartments in addition to the liquid conduit 7. When the liquid conduit 7 is blocked, the electrically controlled stop valve 10 can also be opened to connect the upper and lower compartments, thereby restoring the gas phase space of the upper cavity 5 for the liquid in the lower cavity 14, avoiding safety accidents and serving as a transitional measure in the event of a sudden emergency.

[0031] Based on the above implementation, in a preferred implementation, Figure 1As shown, the bottom end of the liquid storage cylinder 8 extends to the bottom of the lower cavity 14, and a liquid storage cylinder heat conducting sheet 9 is arranged at the bottom of the liquid storage cylinder 8. This arrangement allows the heated liquid to flow through the liquid storage cylinder 8 to the cooler bottom of the lower cavity 14, and the liquid storage cylinder heat conducting sheet 9 allows the cold and hot liquids to exchange heat, preventing the liquid in the liquid storage cylinder 8 from evaporating gas due to temperature rise, thereby hindering the suction effect of the upper cavity 5.

[0032] Based on the above implementation, in a preferred implementation, Figure 2 As shown, the liquid guide tube 7 is located at the center of the partition 6, and the upper cavity heat conducting sheet 18 is radially arranged around the liquid guide tube 7. This arrangement allows the liquid to be basically unimpeded, smoothly and quickly spread on the partition 6 after the upper cavity 5 absorbs the low-temperature liquid, and then the high-temperature gas is quickly cooled by the heat conducting sheet, thereby improving the cooling efficiency.

[0033] Based on the above implementation, in a preferred implementation, Figure 2 As shown, the lower cavity heat conducting sheet 17 is radially arranged around the liquid guiding tube 7, the outer ends of the upper cavity heat conducting sheet 18 and the lower cavity heat conducting sheet 17 are connected to the side wall of the tank body 13, and a heat conducting sheet gap 19 is formed between the inner ends of the upper cavity heat conducting sheet 18 and the inner ends of the lower cavity heat conducting sheet 17. Because the tank body wall is an important source of heat leakage, after the heat conducting sheet is connected to the side wall of the tank body 13, the cooling effect on the tank body wall can be improved, so that the cold energy can be more effectively applied to the place that needs cooling, and a more long-lasting cooling and decompression effect can be achieved. Because a certain chamber structure is formed after the outer end of the heat conducting sheet is connected to the side wall of the tank body 13, in order to avoid the appearance of a closed chamber structure that hinders the flow of gas, a heat conducting sheet gap 19 is set at the inner end of the vertical heat conducting plate.

[0034] Based on the above implementation, in a preferred implementation, Figure 1 As shown, the lower cavity heat conducting sheet 17 includes an air chamber heat conducting sheet 16 and a tank wall heat conducting sheet 15 connected in an inverted L-shaped structure. This arrangement is because gas is relatively difficult to conduct heat, so a wide air chamber heat conducting sheet 16 is arranged on the top of the lower cavity 14, which is conducive to cooling the gas therein. The inner liner of the storage tank is mostly made of steel, which is a good conductor of heat like the heat conducting sheet. In order to cool the side wall of the tank body 13, which is an important heat leakage path, the tank wall heat conducting sheet 15 does not need to be made too wide, thereby saving materials and reducing the weight of the tank body 13.

[0035] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A low-temperature liquid storage tank safety device, used to ensure the pressure safety of the tank body (13), characterized in that: The invention comprises a first safety valve (4), a partition (6), a liquid guide tube (7), an upper cavity heat conductive sheet (18) and a lower cavity heat conductive sheet (17); the partition (6) is disposed horizontally above the tank body (13) to divide the inner cavity of the tank body (13) into an upper cavity (5) and a lower cavity (14); the first safety valve (4) is arranged between the top of the upper cavity (5) and the outside; the liquid guide tube (7) is connected between the upper cavity (5) and the lower cavity (14); the upper end of the liquid guide tube (7) is connected to the partition (6), and the lower end of the liquid guide tube (7) extends to the bottom of the lower cavity (14); an upper cavity heat conductive sheet (18) is vertically arranged on the upper surface of the partition (6), and a lower cavity heat conductive sheet (17) is vertically arranged on the lower surface of the partition (6).

2. The cryogenic liquid storage tank safety device according to claim 1, characterized in that: It also includes a second safety valve (2), which is arranged between the top of the lower cavity (14) and the outside.

3. The cryogenic liquid storage tank safety device according to claim 2, characterized in that: The release pressure value of the second safety valve (2) is higher than the release pressure value of the first safety valve (4), and the second safety valve (2) is communicatively connected to a fault alarm (3), and the fault alarm (3) is triggered when the second safety valve (2) is opened.

4. The cryogenic liquid storage tank safety device according to any one of claims 1 to 3, characterized in that: The upper cavity (5) is filled with nitrogen.

5. The cryogenic liquid storage tank safety device according to any one of claims 1 to 3, characterized in that: The liquid storage cylinder (8) is also included. The liquid storage cylinder (8) is connected to the partition (6) through the bottom end of the liquid storage cylinder (8) is a closed structure and extends into the lower cavity (14). The top end of the liquid storage cylinder (8) is a flat opening. The top end of the liquid storage cylinder (8) protrudes from the upper surface of the partition (6).

6. The cryogenic liquid storage tank safety device according to claim 5, characterized in that: An electrically controlled stop valve (10) is provided at the bottom end of the liquid storage cylinder (8), and the electrically controlled stop valve (10) is connected between the inner cavity of the liquid storage cylinder (8) and the lower cavity (14).

7. The cryogenic liquid storage tank safety device according to any one of claim 5, characterized in that: The bottom end of the liquid storage cylinder (8) extends to the bottom of the lower cavity (14), and a liquid storage cylinder heat conducting sheet (9) is arranged at the bottom of the liquid storage cylinder (8).

8. The cryogenic liquid storage tank safety device according to any one of claims 1 to 3, characterized in that: The liquid guiding tube (7) is located at the center of the partition (6), and the upper cavity heat conducting sheet (18) is radially arranged around the liquid guiding tube (7).

9. The cryogenic liquid storage tank safety device according to any one of claim 8, characterized in that: The lower chamber heat conducting sheet (17) is radially arranged around the liquid guiding tube (7); the outer ends of the upper chamber heat conducting sheet (18) and the lower chamber heat conducting sheet (17) are connected to the side wall of the tank body (13); and a heat conducting sheet gap (19) is formed between the inner ends of the upper chamber heat conducting sheet (18) and the inner ends of the lower chamber heat conducting sheet (17).

10. The cryogenic liquid storage tank safety device according to claim 9, characterized in that: The lower chamber heat conducting sheet (17) comprises an air chamber heat conducting sheet (16) and a tank wall heat conducting sheet (15) which are connected to form an inverted L-shaped structure.

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