Liquid tank nitrogen discharging device and liquid nitrogen discharging method

Abstract

The application discloses a liquid tank nitrogen discharging device and a liquid nitrogen discharging method. The liquid tank nitrogen discharging device comprises a liquid storage tank, a vaporizer connected to the liquid storage tank, a water storage tank arranged below the vaporizer, a circulating water supply assembly connected to the water storage tank, an elastic bag arranged at the upper portion of the water storage tank, a plurality of vertical pipes arranged in the elastic bag, a plurality of sleeves corresponding to the vertical pipes, a scraper connected to the upper end of the sleeve, a mounting rod connected to the sleeves, a lifting assembly arranged at one end of the mounting rod, a plurality of folded edge portions connected to each other, and the lifting assembly is used for driving the sleeve to move in the vertical direction. The liquid tank nitrogen discharging device can remove the ice layer of the vertical pipe, and the hot water circulates in the elastic bag, thereby improving the vaporization efficiency of the liquid nitrogen in the low-temperature environment. The liquid nitrogen discharging method comprises the liquid tank nitrogen discharging device, and the vaporization efficiency of the liquid nitrogen in the low-temperature environment is ensured.

Description

Technical Field

[0001] This invention relates to the technical field of liquid nitrogen refueling for ships, and more particularly to a liquid nitrogen tank venting device and a liquid nitrogen venting method. Background Technology

[0002] The construction of single-fuel powered ships requires steps such as LNG refueling and commissioning to meet the on-site testing needs of ship mooring. Currently, LNG refueling mostly uses nitrogen for filling, and the main method of using nitrogen is to store liquid nitrogen in storage tanks. The discharge time of liquid nitrogen is relatively long, especially in the cold winter, when the discharge time will be further extended.

[0003] To improve the discharge time of liquid nitrogen, existing methods employ vaporizers, which convert liquid nitrogen into gaseous nitrogen through air heat exchange. However, this method is easily affected by ambient temperature, especially in cold winters when heat exchange efficiency is slow, resulting in a slower conversion rate. Furthermore, during the vaporization process in the vaporizer, liquid nitrogen absorbs a significant amount of heat from the surrounding air, causing moisture to condense on the vaporizer. Particularly during periods of high nitrogen consumption and in cold winters, the vaporizer can quickly become covered with a thick layer of ice, further impacting its vaporization efficiency and consequently affecting the nitrogen supply. Summary of the Invention

[0004] To address the above shortcomings, this invention proposes a liquid tank nitrogen venting device that can not only remove the ice layer on the vertical pipe, but also maintain good heat exchange of liquid nitrogen in a low-temperature environment by circulating hot water in an elastic bag, thereby accelerating the vaporization efficiency of liquid nitrogen.

[0005] The present invention also discloses a liquid nitrogen discharge method, which includes using the above-mentioned liquid tank nitrogen discharge device, which can not only remove the ice layer on the vertical pipe, but also maintain good heat exchange of liquid nitrogen in a low-temperature environment by circulating hot water in the elastic bag, thereby accelerating the vaporization efficiency of liquid nitrogen.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A liquid tank nitrogen purging device includes: a liquid storage tank, which is connected to a vaporizer via a first pipeline. The first pipeline is equipped with a first switching valve. The vaporizer includes multiple parallel vertical pipes, with a curved pipe connecting adjacent vertical pipes. The vaporizer is connected to a second pipeline for connecting to a GVU valve box, and the second pipeline is equipped with a second switching valve. A water storage tank is located below the vaporizer and is connected to a circulating water supply assembly for conveying hot water. An elastic bag is provided at the top of the water storage tank, and multiple vertical pipes are housed within the elastic bag. Multiple sleeves are connected to the upper end of the elastic bag, and each sleeve is fitted onto the outside of a vertical pipe. The upper end of each sleeve is connected to a scraper for breaking ice. The multiple sleeves are connected to a mounting rod, and one end of the mounting rod is equipped with a lifting assembly. The elastic bag includes multiple folded edges connected sequentially in a vertical direction. The lifting assembly is used to drive the sleeves to move in a vertical direction, so that the multiple folded edges overlap or unfold in a vertical direction.

[0008] The liquid tank nitrogen venting device according to an embodiment of the present invention has at least the following beneficial effects: In use, the first switch valve is opened and the second switch valve is closed, allowing the liquid nitrogen in the storage tank to be transported to the vaporizer through the first pipeline under the pressure inside the tank, thereby filling multiple vertical pipes and curved pipes with liquid nitrogen. When the outside temperature is high in summer, the sleeve is located at the lower part of the vertical pipe. At this time, the liquid nitrogen mainly exchanges heat with the air through convection, allowing the liquid nitrogen to gradually absorb heat, thus enabling the liquid nitrogen to vaporize using the outside air temperature to form gaseous nitrogen. Then, the second switch valve is opened, allowing the gaseous nitrogen to be output to the GVU valve box through the second pipeline. When the outside temperature is low during winter, the liquid nitrogen vaporization process can easily cause ice to form on the riser. The lifting mechanism then moves the mounting rod upwards, causing the sleeve to drive the scraper to remove the ice from the riser. The elastic bag then expands to form a cavity that can accommodate multiple risers. Finally, the circulating water supply system replenishes the storage tank with hot water, filling the interior of the elastic bag. This allows the liquid nitrogen to primarily exchange heat through the hot water, ensuring a high vaporization efficiency even in winter. This further shortens the time required to vent nitrogen from the tank, thus guaranteeing the supply of nitrogen.

[0009] The elastic bag features multiple overlapping or unfolding folds along the vertical direction, which allows it to stretch or compress vertically, enabling it to expand and form cavities of varying heights as the sleeve moves.

[0010] Furthermore, the scraper is provided in two parts, which are joined together to form a hollow frustum-shaped structure, and the small end of the scraper is provided with multiple pointed protrusions.

[0011] Furthermore, the sleeve has a square portion extending radially along the vertical tube, the scraper is movably disposed on the square portion, the square portion is threadedly connected to a bolt, one end of the bolt is provided with a limiting portion, an elastic element is provided between the limiting portion and the scraper, and the elastic element drives the scraper to press against the outer wall of the vertical tube.

[0012] Furthermore, the lifting assembly includes a motor, a screw, and a slider. The screw extends vertically, the motor is connected to the screw, the slider is threadedly engaged with the screw, and the mounting rod is connected to the slider. When the motor rotates, the slider drives the mounting rod to move vertically.

[0013] Furthermore, the mounting rod is a hollow tube connected to the interior of the elastic bag, the circulating water supply assembly includes a water storage tank, the interior of the water storage tank is provided with a heating wire, the water storage tank is connected to the water storage tank through a third pipeline, the water storage tank is connected to a water pump, and one end of the water pump is connected to the hollow tube through a fourth pipeline.

[0014] Furthermore, it also includes a controller, the water storage tank is equipped with a temperature sensor, the elastic bag is equipped with a liquid level sensor, and both the third pipeline and the fourth pipeline are equipped with solenoid valves. The temperature sensor, the liquid level sensor and the solenoid valve are all electrically connected to the controller.

[0015] Furthermore, it also includes a controller, the second pipeline is provided with a return pipe connected to the liquid storage tank, the return pipe is connected to a third switching valve, the liquid storage tank is provided with a pressure sensor, and the pressure sensor and the third switching valve are electrically connected to the controller.

[0016] Furthermore, the reflux pipe is connected to the upper end of the liquid storage tank, and the reflux pipe is equipped with a one-way valve.

[0017] This invention also discloses a liquid nitrogen discharge method, including a liquid tank nitrogen discharge device using any of the above-mentioned technical solutions. The liquid nitrogen discharge method specifically includes the following steps:

[0018] S1, open the first switch valve and close the second switch valve, and the liquid nitrogen in the storage tank flows to the vaporizer under pressure;

[0019] S2, stop the operation of the lifting assembly and the circulating water supply assembly, so that liquid nitrogen fills the multiple vertical pipes and curved pipes, and the liquid nitrogen undergoes convective heat exchange with the air through the vaporizer;

[0020] S3, if icing occurs in the heat exchange of the vertical pipe, the lifting assembly is operated to drive the mounting rod to move upward, so that the sleeve drives the scraper to scrape off the ice layer located in the vertical pipe, and at the same time the elastic bag is expanded to form a second cavity to accommodate multiple vertical pipes.

[0021] S4, the circulating water supply component is operated so that hot water can be circulated to the water storage tank, thereby filling the second cavity with hot water to heat the vertical pipe, and thus driving liquid nitrogen to exchange heat to form gaseous nitrogen.

[0022] S5, open the second switch valve to allow the vaporized gaseous nitrogen to be discharged through the second pipeline.

[0023] The above steps of the liquid nitrogen discharge method can not only remove the ice layer on the vertical pipe by scraping, but also stretch the elastic bag to form a cavity by moving the sleeve upward. It also facilitates the circulation of hot water in the elastic bag, so that the liquid nitrogen can maintain good heat exchange in a low-temperature environment, thereby accelerating the vaporization efficiency of liquid nitrogen.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0026] Figure 1 This is a schematic diagram of one embodiment of a liquid tank nitrogen venting device according to the present invention;

[0027] Figure 2 for Figure 1 A schematic diagram of the assembly of the vaporizer, sleeve and scraper;

[0028] Figure 3 for Figure 1 A partial sectional view of the assembly of the vertical pipe, sleeve and scraper.

[0029] In the diagram: storage tank 100, first pipeline 110, first switch valve 120, vaporizer 200, vertical pipe 210, bend pipe 220, second pipeline 230, second switch valve 240, return pipe 250, third switch valve 260, water tank 300, elastic bag 310, sleeve 320, square part 321, bolt 322, limiting part 323, elastic part 324, groove 325, scraper 330, pointed protrusion 331, mounting rod 340, third pipeline 350, motor 400, screw 410, slider 420. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "inner", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0032] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] See Figures 1 to 3A liquid tank nitrogen purging device includes: a liquid storage tank 100 and a water storage tank 300. The liquid storage tank 100 is connected to a vaporizer 200 via a first pipe 110, which is equipped with a first switching valve 120. The vaporizer 200 includes multiple parallel vertical pipes 210, with a bend pipe 220 connecting adjacent vertical pipes 210. The vaporizer 200 is connected to a second pipe 230 for connecting to a GVU valve box, which is equipped with a second switching valve 240. The water storage tank 300 is located below the vaporizer 200 and is connected to a circulating water supply assembly for conveying hot water. The upper part of the water storage tank 300 is provided with an elastic bag 310, and multiple vertical tubes 210 are built into the elastic bag 310. Multiple sleeves 320 are connected to the upper end of the elastic bag 310. The sleeves 320 are fitted onto the outside of the vertical tubes 210 one by one. The upper end of the sleeves 320 is connected to a scraper 330 for breaking ice. Multiple sleeves 320 are connected to a mounting rod 340. One end of the mounting rod 340 is provided with a lifting component. The elastic bag 310 includes multiple folded parts connected in sequence along the vertical direction. The lifting component is used to drive the sleeves 320 to move in the vertical direction so that the multiple folded parts overlap or unfold in the vertical direction.

[0035] In operation, the liquid nitrogen venting device with the above structure is operated by first opening the first switch valve 120 and closing the second switch valve 240. This allows the liquid nitrogen in the storage tank 100 to be transported to the vaporizer 200 through the first pipeline 110 under the pressure inside the tank, filling the multiple vertical pipes 210 and the curved pipe 220 with liquid nitrogen. When the outside temperature is high in summer, the sleeve 320 is located at the lower part of the vertical pipe 210. At this time, the liquid nitrogen mainly exchanges heat with the air through convection, allowing the liquid nitrogen to gradually absorb heat and vaporize using the outside air temperature to form gaseous nitrogen. Then, the second switch valve 240 is opened, allowing the gaseous nitrogen to be output to the GVU valve box through the second pipeline 230. When the outside temperature is low during winter, the vaporization process of liquid nitrogen can easily cause ice to form on the vertical pipe 210. The lifting component drives the mounting rod 340 to move upward, so that the sleeve 320 drives the scraper 330 to scrape the ice layer on the vertical pipe 210 upward. Then the elastic bag 310 unfolds to form a cavity that can accommodate multiple vertical pipes 210. Finally, the circulating water supply component replenishes the water storage tank 300 with hot water, so that the hot water fills the interior of the elastic bag 310. This allows the liquid nitrogen to exchange heat mainly through hot water, which helps to ensure that the liquid nitrogen can maintain a high vaporization efficiency even in winter, further shortens the time for nitrogen to be discharged from the liquid tank, and thus ensures the supply of nitrogen.

[0036] It is understood that the water storage tank 300 includes multiple plates that together form a rectangular groove. The elastic bag 310 is a bag that extends vertically through the tank. The lower end of the elastic bag 310 is connected to the inner wall of the groove opening, thus forming a cavity that can be fitted onto multiple vertical pipes 210. The upper end of the elastic bag 310 is connected to the outer peripheral wall of multiple sleeves 320 to form an opening. The elastic bags 310 between adjacent sleeves 320 can be connected by needle and thread to close the opening as much as possible, which helps to reduce the heat loss of the subsequently replenished hot water. In some embodiments, the inner wall of the elastic bag 310 is adhered with an insulation layer, which further reduces the heat loss of the hot water. In addition, the elastic bag 310 has multiple overlapping or unfoldable folded edges, which allows the elastic bag 310 to unfold or compress in the vertical direction, thus enabling the elastic bag 310 to unfold and form cavities of different heights as the sleeves 320 move. Understandably, the folded edge can adopt a structure similar to that of a corrugated tube or a folding fan, thereby ensuring that the elastic bag 310 has a large stretching or compression capacity.

[0037] See Figure 2 and Figure 3 Furthermore, two scrapers 330 are provided, which are joined together to form a hollow frustum-shaped structure. The small end of the scraper 330 is provided with multiple pointed protrusions 331, thereby applying local pressure using the multiple pointed protrusions 331 to quickly break the ice layer in the vertical pipe 210. The outer wall of the scraper 330 is formed with a slope for guiding the flow, so that the broken ice blocks can be separated from the vertical pipe 210 along the slope.

[0038] See Figure 2 and Figure 3 Furthermore, the sleeve 320 has a square portion 321 extending radially along the vertical pipe 210. A scraper 330 is movably disposed on the square portion 321. A bolt 322 is threadedly connected to the square portion 321. One end of the bolt 322 has a limiting portion 323. An elastic element 324 is provided between the limiting portion 323 and the scraper 330, driving the scraper 330 to press against the outer wall of the vertical pipe 210. Specifically, the scraper 330 has a square hole through which the square portion 321 passes, and the square portion 321 has a threaded groove that threadedly engages with the bolt 322. During installation, the square portion 321 passes through the square hole, allowing the scraper 330 to move only relative to the square portion 321. Then, the bolt 322 is screwed into the threaded groove, allowing the elastic element 324 to press against the scraper 330. Finally, under the action of the elastic element 324, the scraper 330 remains pressed against the outer wall of the vertical pipe 210. Understandably, the elastic element 324 can be made of a spring, or other materials such as rubber or plastic that have elastic deformation.

[0039] See Figure 1Furthermore, the lifting assembly includes a motor 400, a screw 410, and a slider 420. The screw 410 extends vertically, the motor 400 is connected to the screw 410, the slider 420 is threadedly engaged with the screw 410, and the mounting rod 340 is connected to the slider 420. When the motor 400 rotates, the slider 420 drives the mounting rod 340 to move vertically. Specifically, in use, the motor 400 drives the screw 410 to rotate, causing the slider 420 to move along the length of the screw 410 under the action of the thread. This causes the mounting rod 340 to simultaneously drive multiple sleeves 320 upwards, ultimately driving the corresponding scraper 330 to break the ice layer of the corresponding vertical pipe 210 upwards. In some embodiments, the lifting assembly may also use a fixed pulley to wind the suspension rope, or a cylinder to drive the mounting rod 340 to move up or down; details are not provided here.

[0040] See Figure 3 Furthermore, the mounting rod 340 is a hollow tube connected to the interior of the elastic bag 310. The circulating water supply assembly includes a water storage tank, which contains a heating wire. The water storage tank 300 is connected to the water storage tank via a third pipe 350. The water storage tank is connected to a water pump, one end of which is connected to the hollow tube via a fourth pipe. Specifically, in use, when hot water is needed to fill the elastic bag 310, the water in the water storage tank is heated by the heating wire. The water pump then supplies hot water to the hollow tube, allowing the hot water in the water storage tank to fall along the outer wall of the vertical pipe 210 and finally replenish the elastic bag 310 and the water storage tank 300. Finally, the water in the water storage tank 300 flows back to the water storage tank via the third pipe 350, thus completing the recycling of hot water. It is understood that the sleeve has a groove 325 connected to the hollow tube, allowing hot water to flow into the interior of the elastic bag 310 through the groove.

[0041] See Figure 1 Furthermore, the system also includes a controller. The water storage tank 300 is equipped with a temperature sensor, the elastic bag 310 with a level sensor, and both the third and fourth pipelines are equipped with solenoid valves. The temperature sensor, level sensor, and solenoid valves are all electrically connected to the controller. Specifically, when the temperature sensor detects that the temperature of the water storage tank 300 is lower than the set temperature, the controller controls the solenoid valve located in the third pipeline 350 to operate, allowing water in the water storage tank 300 to flow back to the storage tank for reheating. The heated water then continues to replenish the elastic bag 310 through the fourth pipeline. Conversely, when the level sensor detects that the water level in the elastic bag 310 is higher than the set value, the controller closes the solenoid valve located in the fourth pipeline and then opens the third pipeline 350 to allow some water to flow back to the storage tank. It is understood that, to regulate the direction of water flow, the third and fourth pipelines are equipped with check valves to prevent backflow. The controller can be controlled using a PLC chip or an input program.

[0042] See Figure 1 Furthermore, it also includes a controller. The second pipeline 230 is equipped with a return pipe 250 connected to the liquid storage tank 100. The return pipe 250 is connected to a third switching valve 260. The liquid storage tank 100 is equipped with a pressure sensor, and the pressure sensor and the third switching valve 260 are electrically connected to the controller. Specifically, in use, the first switching valve 120 is first opened, and the second switching valve 240 and the third switching valve 260 are closed, so that the liquid nitrogen in the liquid storage tank 100 can fill the multiple vertical pipes 210 and the curved pipe 220 by relying on the internal pressure of the liquid tank. Then, wait for the liquid nitrogen to vaporize and form gaseous nitrogen. Finally, open the second switching valve 240 so that the gaseous nitrogen can be output to the GVU valve box through the second pipeline 230. When the pressure in the liquid storage tank 100 is lower than the liquid nitrogen discharge pressure, the third switching valve 260 can be opened to supplement some gaseous nitrogen into the liquid storage tank 100, thereby increasing the pressure in the liquid storage tank 100 so that the liquid storage tank 100 can continue to output liquid nitrogen. It is understandable that the first switching valve 120, the second switching valve 240 and the third switching valve 260 can all be existing electric switching valves. The control principle of electric switching valves is based on a switching structure, which contains an electric actuator and a valve body, and can quickly realize the on-off control of the medium. This will not be described in detail here.

[0043] See Figure 1 Furthermore, the return pipe 250 is connected to the upper end of the storage tank 100. The return pipe 250 is equipped with a one-way valve to prevent liquid nitrogen from flowing back into the return pipe 250, thereby ensuring that the liquid nitrogen in the storage tank 100 can be converted into gaseous state for transportation.

[0044] This invention also discloses a liquid nitrogen discharge method, including a liquid tank nitrogen discharge device using any of the above-mentioned technical solutions. The liquid nitrogen discharge method specifically includes the following steps:

[0045] S1, open the first switch valve 120 and close the second switch valve 240. The liquid nitrogen in the storage tank 100 flows to the vaporizer 200 under pressure.

[0046] S2, stop the operation of the lifting component and the circulating water supply component, so that liquid nitrogen fills the multiple vertical pipes 210 and the curved pipes 220, and the liquid nitrogen undergoes convective heat exchange with the air through the vaporizer 200;

[0047] S3, if icing occurs during heat exchange in the vertical pipe 210, the lifting assembly is operated to drive the mounting rod 340 upward, so that the sleeve 320 drives the scraper 330 to scrape off the ice layer located in the vertical pipe 210, and at the same time, the elastic bag 310 is expanded to form a second cavity to accommodate multiple vertical pipes 210.

[0048] S4, the circulating water supply component is operated so that hot water can be circulated to the water storage tank 300, thereby filling the second cavity with hot water to heat the vertical pipe 210, and then driving the liquid nitrogen to exchange heat to form gaseous nitrogen.

[0049] S5, open the second switch valve 240, so that the vaporized gaseous nitrogen is discharged through the second pipeline 230.

[0050] The above steps of the liquid nitrogen discharge method can not only remove the ice layer on the vertical pipe 210 by scraper 330, but also cause the elastic bag 310 to stretch and form a cavity by moving the sleeve 320 upward. It is also beneficial to maintain good heat exchange of liquid nitrogen in a low-temperature environment by circulating hot water in the elastic bag 310, thereby accelerating the vaporization efficiency of liquid nitrogen.

[0051] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A nitrogen purging device for a liquid tank, characterized in that, include: A liquid storage tank (100) is connected to a vaporizer (200) via a first pipeline (110). The first pipeline (110) is equipped with a first switching valve (120). The vaporizer (200) includes a plurality of parallel vertical pipes (210). A bend pipe (220) connects two adjacent vertical pipes (210). The vaporizer (200) is connected to a second pipeline (230) for connecting to a GVU valve box. The second pipeline (230) is equipped with a second switching valve (240). A water storage tank (300) is located below the vaporizer (200). The water storage tank (300) is connected to a circulating water supply assembly for conveying hot water. An elastic bag (310) is provided on the upper part of the water storage tank (300). Multiple vertical pipes (210) are placed inside the elastic bag (310). Multiple sleeves (320) are connected to the upper end of the elastic bag (310). Each sleeve (320) is fitted onto a vertical pipe. Outside of (210), the upper end of the sleeve (320) is connected to a scraper (330) for breaking ice. Multiple sleeves (320) are connected to a mounting rod (340). One end of the mounting rod (340) is provided with a lifting component. The elastic bag (310) includes multiple folded edges connected in sequence along the vertical direction. The lifting component is used to drive the sleeve (320) to move in the vertical direction so that the multiple folded edges overlap or unfold in the vertical direction.

2. The liquid tank nitrogen venting device according to claim 1, characterized in that, Two scrapers (330) are provided, and the two scrapers (330) are spliced ​​together to form a hollow frustum structure. The small end of the scraper (330) is provided with multiple pointed protrusions (331).

3. The liquid tank nitrogen venting device according to claim 1, characterized in that, The sleeve (320) is provided with a square portion (321) extending radially along the vertical tube (210). The scraper (330) is movably provided on the square portion (321). The square portion (321) is threadedly connected with a bolt (322). One end of the bolt (322) is provided with a limiting portion (323). An elastic element (324) is provided between the limiting portion (323) and the scraper (330). The elastic element (324) drives the scraper (330) to press against the outer wall of the vertical tube (210).

4. The liquid tank nitrogen purging device according to claim 1, characterized in that, The lifting assembly includes a motor (400), a screw (410), and a slider (420). The screw (410) extends vertically, and the motor (400) is connected to the screw (410). The slider (420) is threadedly engaged with the screw (410), and the mounting rod (340) is connected to the slider (420). When the motor (400) rotates, the slider (420) drives the mounting rod (340) to move vertically.

5. The liquid tank nitrogen venting device according to claim 1, characterized in that, The mounting rod (340) is a hollow tube that communicates with the interior of the elastic bag (310). The circulating water supply assembly includes a water storage tank. The interior of the water storage tank is equipped with a heating wire. The water storage tank (300) is connected to the water storage tank through a third pipe (350). The water storage tank is connected to a water pump. One end of the water pump is connected to the hollow tube through a fourth pipe.

6. A liquid tank nitrogen venting device according to claim 5, characterized in that, It also includes a controller, the water tank (300) is equipped with a temperature sensor, the elastic bag (310) is equipped with a liquid level sensor, the third pipeline (350) and the fourth pipeline are both equipped with solenoid valves, and the temperature sensor, the liquid level sensor and the solenoid valve are all electrically connected to the controller.

7. A liquid tank nitrogen purging device according to claim 1, characterized in that, It also includes a controller, the second pipeline (230) is provided with a return pipe (250) connected to the liquid storage tank (100), the return pipe (250) is connected to a third switching valve (260), the liquid storage tank (100) is provided with a pressure sensor, and the pressure sensor and the third switching valve are electrically connected to the controller.

8. A liquid tank nitrogen venting device according to claim 7, characterized in that, The reflux pipe (250) is connected to the upper end of the liquid storage tank, and the reflux pipe (250) is equipped with a one-way valve.

9. A method for discharging liquid nitrogen, using a liquid tank nitrogen discharge device according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1, open the first switch valve (120) and close the second switch valve (240), and the liquid nitrogen in the storage tank (100) flows to the vaporizer (200) under pressure; S2, stop the operation of the lifting assembly and the circulating water supply assembly, so that liquid nitrogen fills the multiple vertical pipes (210) and the curved pipes (220), and the liquid nitrogen undergoes convective heat exchange with the air through the vaporizer (200); S3, if the vertical pipe (210) freezes during heat exchange, the lifting assembly is operated to drive the mounting rod (340) to move upward, so that the sleeve (320) drives the scraper (330) to scrape off the ice layer located on the vertical pipe (210), and at the same time the elastic bag (310) unfolds to form a second cavity to accommodate multiple vertical pipes (210); S4, the circulating water supply component is operated so that hot water can be circulated to the water storage tank (300), thereby filling the second cavity with hot water to heat the vertical pipe (210), and driving liquid nitrogen to exchange heat to form gaseous nitrogen. S5, open the second switch valve (240) so that the vaporized gaseous nitrogen is discharged through the second pipeline (230).

Images