Liquid nitrogen filling system and liquid nitrogen filling method

Abstract

The invention belongs to the technical field of liquid nitrogen filling, and discloses a liquid nitrogen filling system and a liquid nitrogen filling method.The liquid nitrogen filling system comprises a plate body, and the plate body is provided with a conveying pipe and an exhaust pipe; the conveying pipe is communicated with an external liquid nitrogen output pipeline, the exhaust pipe is arranged on the plate body in a manner of penetrating through the plate body, and the plate body is used for covering a tank opening of an external tank body and can completely cover the tank opening; and when the plate body covers the tank opening, the lower end of the exhaust pipe extends to the rated filling liquid level depth of the tank body. The filling system aims at solving the problems of safety and liquid level monitoring in the liquid nitrogen filling process. In addition, the invention further discloses a liquid nitrogen filling method adopting the liquid nitrogen filling system.

Description

Technical Field

[0001] This application belongs to the field of liquid nitrogen filling technology, and more specifically, relates to a liquid nitrogen filling system and a liquid nitrogen filling method. Background Technology

[0002] Liquid nitrogen filling, a crucial step in industrial gas applications, is widely used in biobanks, medical cryopreservation, metal processing, food quick-freezing, and scientific research. Liquid nitrogen, with a temperature of -196℃ at atmospheric pressure, possesses extremely high cryogenic properties and a rapid phase change capability. During the filling process, it must be transferred and stored using specific insulated containers, such as Dewar flasks. The violent vaporization of liquid nitrogen produces a large amount of cryogenic nitrogen gas, accompanied by a thick white mist. This physical characteristic presents significant technical challenges and safety risks to traditional filling operations.

[0003] In the filling process, many scenarios still rely on manual indirect hand-held filling tube operation. Specifically, a rod is attached to the filling tube, and the tube is held indirectly by hand. Operators must insert the filling tube into the Dewar can's opening at close range and control the valve to fill, a process fraught with multiple safety hazards, such as splashing due to shaking. Therefore, manual hand-held operation requires high-level protective equipment, strict operating procedures, and is inherently a high-risk operation.

[0004] Another key technical challenge lies in liquid level monitoring. Currently, the main methods for determining whether a Dewar can is full are sound and overflow. However, sound detection is inaccurate due to differences in hearing among operators; overflow detection is too risky and wasteful. Therefore, achieving reliable and continuous liquid level monitoring during the filling process has always been a technical bottleneck. Summary of the Invention

[0005] The main purpose of this application is to provide a liquid nitrogen filling system and a liquid nitrogen filling method.

[0006] According to a first aspect of this application, a liquid nitrogen filling system is provided, which aims to solve the problems of safety and liquid level monitoring during the liquid nitrogen filling process; according to a second aspect of this application, a liquid nitrogen filling method using the liquid nitrogen filling system is provided.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] A liquid nitrogen filling system includes: a plate having a delivery pipe and an exhaust pipe;

[0009] The delivery pipe is connected to the liquid nitrogen output pipe of the external device, and the exhaust pipe is installed on the plate in a way that penetrates the plate. The plate is used to cover the opening of the tank of the external device and can completely cover the opening.

[0010] When the plate covers the tank opening, the lower end of the vent pipe extends to the tank's rated filling depth.

[0011] In the liquid nitrogen filling system described above, the liquid nitrogen filling system also includes a frame, which has an adjusting element for adjusting the position of the plate in the vertical direction; the plate is connected to the adjusting element.

[0012] In the liquid nitrogen filling system described above, the plate is disc-shaped, and the axes of the plate, exhaust pipe, and delivery pipe are all arranged vertically. The delivery pipe runs through the plate, and the length of the portion of the delivery pipe protruding from the upper surface of the plate is less than the length of the portion protruding from the lower surface of the plate. The length of the portion of the delivery pipe protruding from the lower surface of the plate is greater than the length of the portion of the exhaust pipe protruding from the lower surface of the plate.

[0013] In the liquid nitrogen filling system described above, the upper end of the delivery pipe has a threaded connector for threading a braided hose. The delivery pipe is connected to an external liquid nitrogen output pipe through the braided hose.

[0014] In the liquid nitrogen filling system described above, the frame includes a fixed frame and connecting frames. The fixed frame is fixedly connected to the ground, and there are multiple connecting frames. The multiple connecting frames are arranged at intervals along the length of the fixed frame and are fixedly connected to the fixed frame. The multiple connecting frames divide the space into multiple filling positions for placing the tank. Each filling position has a plate, and the adjustment component is located on the connecting frame.

[0015] In the liquid nitrogen filling system described above, the connecting frame has a slide rail on the side facing its corresponding filling position. The slide rail is arranged vertically. The adjusting component includes a slider that matches the slide rail. A hand-tightening bolt is screwed onto the slider. The hand-tightening bolt is used to lock the slider onto the slide rail. A connecting rod is also connected to the slider. One end of the connecting rod is connected to the slider through a mounting plate, and the other end is connected to the plate body. The plate body is located in the vertical area of ​​the filling position.

[0016] In the liquid nitrogen filling system described above, the bottom of the connecting frame is located above the ground.

[0017] In the liquid nitrogen filling system described above, the slide rail includes a connecting plate, which is vertically arranged and connected to the side of the connecting frame facing its corresponding filling position. The surface of the connecting plate has a protrusion, and the protrusion has recesses on both sides along its length. The slider has a through groove that matches the protrusion. The slider is slidably connected to the protrusion through the through groove. One side of the slider has a threaded hole that communicates with the through groove. The threaded hole is used to connect a hand-tightening bolt.

[0018] This application also provides a liquid nitrogen filling method, which involves a Dewar flask and a liquid nitrogen output pipeline. The liquid nitrogen output pipeline has a control valve and is connected to an external liquid nitrogen storage system for outputting liquid nitrogen. This method uses a liquid nitrogen filling system, and the specific method is as follows:

[0019] Place the plate over the mouth of the Dewar jar, open the control valve, and let liquid nitrogen into the Dewar jar. At this time, judge the liquid nitrogen level in the Dewar jar by observing the white mist coming out of the exhaust pipe.

[0020] If the white mist decreases or disappears instantly, close the control valve; filling is now complete.

[0021] In the liquid nitrogen filling system described above, there is a flow meter on the liquid nitrogen output pipe and a level gauge on the plate.

[0022] One of the above-mentioned technical solutions in this application has at least one of the following advantages or beneficial effects:

[0023] 1. The exhaust pipe of this application not only has a pressure relief function, but also allows the operator to judge whether the Dewar can is full by observing the amount of white mist emitted from the exhaust pipe during filling. In addition, the exhaust pipe is installed on the plate in a way that penetrates through the plate, and the part of the exhaust pipe that protrudes from the upper surface of the plate can also provide a gripping position for the operator.

[0024] 2. This application uses a frame as a support structure, and adjusts the vertical position of the plate by adjusting the adjustment component. During filling, the operator does not need to operate it by hand, which improves the safety of filling.

[0025] 3. The plate design of this application can not only prevent liquid nitrogen from splashing, but also guide the direction of the white mist between the plate and the mouth of the Dewar canister, so as to avoid affecting the operator's observation of the exhaust pipe.

[0026] 4. The bottom of the connecting frame of this application is located above the ground, and the space between the bottom of the connecting frame and the ground can accommodate a trolley, which makes it convenient for operators to use the trolley to carry the Dewar cans for filling. Attached Figure Description

[0027] The present application will be further described below with reference to the accompanying drawings and embodiments;

[0028] Figure 1 This is a perspective view of the plate body of Embodiment 1 of this application;

[0029] Figure 2 This is a perspective view of the liquid nitrogen filling system of Embodiment 1 of this application;

[0030] Figure 3 This is a front view of the liquid nitrogen filling system of Embodiment 1 of this application;

[0031] Figure 4 This is a side view of the liquid nitrogen filling system of Embodiment 1 of this application;

[0032] Figure 5 yes Figure 2 Enlarged view of a portion at point A;

[0033] Figure 6 This is a schematic diagram of the filling process in Embodiment 2 of this application;

[0034] The figure labels for each figure are as follows:

[0035] Plate 1; Frame 2; Conveying pipe 11; Exhaust pipe 12; Adjusting component 21; Fixing frame 22; Connecting frame 23; Filling position 24; Threaded joint 111; Slider 211; Hand-tightening bolt 212; Connecting rod 213; Mounting plate 214; Slide rail 231; Through groove 2111; Connecting plate 2311; Protrusion 2312; Recess 2313. Detailed Implementation

[0036] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0037] The following disclosure provides many different implementation methods or examples for different schemes of implementing this application.

[0038] Example 1

[0039] Reference Figures 1 to 5 As shown, a liquid nitrogen filling system includes: a plate 1, on which a delivery pipe 11 and an exhaust pipe 12 are provided;

[0040] The delivery pipe 11 is connected to the liquid nitrogen output pipe of the external device, and the exhaust pipe 12 is installed on the plate 1 in a way that penetrates the plate 1. The plate 1 is used to cover the opening of the tank of the external device and can completely cover the opening.

[0041] When plate 1 covers the tank opening, the lower end of vent pipe 12 extends to the rated filling depth of the tank.

[0042] It should be noted that in this embodiment, a Dewar flask is used as the tank body, and the plate 1 covers the mouth of the Dewar flask. The mouth of the Dewar flask is not sealed by the plate 1; the two are merely in overlapping contact. Therefore, during the filling process, the white mist has two exit paths: the first is the gap between the plate 1 and the mouth of the Dewar flask, and the second is the position of the exhaust pipe 12. The Dewar flask is existing technology in this field. Regarding the length of the exhaust pipe 12, the operator sets it according to the actual volume of the Dewar flask and the filling volume. That is, the depth to which the lower end of the exhaust pipe 12 extends into the Dewar flask is the rated filling liquid level depth. Considering the time required for the operator to close the valve and perform other operations, it is preferably located 5-10 cm below the rated liquid level. The plate 1, exhaust pipe 12, and conveying pipe 11 are preferably made of stainless steel.

[0043] In actual use, the operator places the Dewar canister on the ground and then covers the canister opening with plate 1, ensuring that both the exhaust pipe 12 and the delivery pipe 11 extend into the Dewar canister. The operator then opens the control valve on the liquid nitrogen output pipe to begin injecting liquid nitrogen. During the injection process, the liquid nitrogen undergoes violent vaporization, producing a large amount of white mist. This white mist is actually fine water droplets formed by the condensation of water vapor in the air. The white mist is discharged from the gap between plate 1 and the Dewar canister opening, as well as from the exhaust pipe 12. In the exhaust pipe 12, the internal pressure of the Dewar canister causes the white mist to rise along the exhaust pipe 12. At the Dewar canister opening, the white mist tends to sink under the guidance of plate 1 and its own weight, thus preventing the white mist at the canister opening from affecting the operator's observation of the white mist in the exhaust pipe 12.

[0044] During the filling process, as the liquid nitrogen in the Dewar canister rises, the liquid nitrogen level gradually approaches the lower end of the vent pipe 12. When the liquid nitrogen level and the lower end of the vent pipe 12 reach a certain distance, a liquid seal effect is formed, and the white mist emitted from the vent pipe 12 momentarily decreases or disappears. At this point, the liquid nitrogen level is the preset filling position. The control valve is then closed, and filling is complete. Furthermore, regarding liquid level judgment, the hissing sound produced by the vaporization of liquid nitrogen is particularly noticeable when the liquid nitrogen level is close to the canister opening. In this embodiment, this sound can also be introduced for secondary judgment to improve the accuracy of liquid level determination.

[0045] In this embodiment, the liquid nitrogen filling system also includes a frame 2, which has an adjusting member 21 for adjusting the position of the plate 1 in the vertical direction; the plate 1 is connected to the adjusting member 21.

[0046] More specifically, through the design of the frame 2 and the adjusting component 21, the operator can adjust the position of the plate 1 in the vertical direction by adjusting the adjusting component 21.

[0047] In this embodiment, the plate 1 is disc-shaped, and the axes of the plate 1, the exhaust pipe 12 and the conveying pipe 11 are all arranged vertically. The conveying pipe 11 is arranged through the plate 1. The length of the portion of the conveying pipe 11 protruding from the upper surface of the plate 1 is less than the length of the portion protruding from the lower surface of the plate 1. The length of the portion of the conveying pipe 11 protruding from the lower surface of the plate 1 is greater than the length of the portion of the exhaust pipe 12 protruding from the lower surface of the plate 1.

[0048] In practical use, the plate 1 is not limited to a disc shape. Considering that the mouth of the Dewar can is circular, a disc-shaped plate 1 can better fit the mouth. The operator only needs to ensure that the plate 1 can completely cover the mouth. In this embodiment, both the exhaust pipe 12 and the delivery pipe 11 are arranged vertically. For the exhaust pipe 12, the lower end is used for liquid level control, and the upper end can be used as a handhold for the operator. For the delivery pipe 11, the vertical arrangement of the delivery pipe 11 not only saves space, but also allows it to be shorter, especially the length of the part protruding from the upper surface of the plate 1. This part directly affects the flow path of liquid nitrogen. Making it shorter makes the pipe through which liquid nitrogen travels from the liquid nitrogen output pipe to the Dewar can be shorter.

[0049] Preferably, the upper end of the delivery pipe 11 has a threaded connector 111, which is used to thread a braided hose. The delivery pipe 11 is connected to an external liquid nitrogen output pipe through the braided hose.

[0050] Regarding braided hoses, this is existing technology in the field. For details, please refer to the record on Baidu Encyclopedia. Those skilled in the art know that both ends of the braided hose have pipe fittings, specifically threaded pipe fittings, which are threaded to the threaded fitting 111 of the delivery pipe 11.

[0051] More preferably, the frame 2 includes a fixed frame 22 and a connecting frame 23. The fixed frame 22 is fixedly connected to the ground. There are multiple connecting frames 23. The multiple connecting frames 23 are arranged at intervals along the length of the fixed frame 22 on the fixed frame 22. The connecting frames 23 are fixedly connected to the fixed frame 22. The multiple connecting frames 23 divide the multiple filling positions 24 for placing Dewar cans. Each filling position 24 has a plate 1. The adjusting member 21 is located on the connecting frame 23.

[0052] In actual use, the number of actual filling positions 24 is not limited in this embodiment. However, the number of Dewar cans filled in filling positions 24 should be determined according to the number of operators. Since the filling system is operated by manual valve opening and closing, the number of Dewar cans filled needs to ensure that the operators can keep an eye on it and close the valve in time.

[0053] In this embodiment, the connecting frame 23 has a slide rail 231 on the side facing its corresponding filling position 24. The slide rail 231 is arranged vertically. The adjusting member 21 includes a slider 211 that matches the slide rail 231. A hand-tightening bolt 212 is screwed onto the slider 211. The hand-tightening bolt 212 is used to lock the slider 211 onto the slide rail 231. A connecting rod 213 is also connected to the slider 211. One end of the connecting rod 213 is connected to the slider 211 through a mounting plate 214, and the other end is connected to the plate body 1. The plate body 1 is located in the vertical area of ​​the filling position 24.

[0054] Specifically, regarding the slide rail 231 and slider 211, considering the influence of temperature and humidity caused by the white fog, in this embodiment, the slide rail 231 and slider 211 adopt a purely mechanical friction type to avoid affecting the lubricating oil between the slide rail 231 and slider 211. Regarding the slider 211 and slide rail 231 used in this embodiment, the slide rail 231 includes a connecting plate 2311, which is vertically arranged and connected to the side of the connecting frame 23 facing its corresponding filling position 24. The surface of the connecting plate 2311 has a protrusion 2312, and the protrusion 2312 has recesses 2313 on both sides along its length. The slider 211 has a through groove 2111 that matches the protrusion 2312. The slider 211 is slidably connected to the protrusion 2312 through the through groove 2111. One side of the slider 211 has a threaded hole (not shown in the figure) communicating with the through groove 2111, which is used to thread a hand-tightening bolt 212.

[0055] More specifically, the main function of the slide rail 231 is to provide a path limit for the movement of the slider 211, ensuring that the slider 211 can only move in the vertical direction. With the help of the hand-tightening bolt 212 located on one side of the slider 211, the operator can loosen the hand-tightening bolt 212, adjust the slider 211 to the preset position, and then tighten the hand-tightening bolt 212 to fix the slider 211 at the preset height.

[0056] In this embodiment, the connection between the connecting frame 23 and the fixing frame 22 is preferably made by welding. The connection between the fixing frame 22 and the ground is preferably made by screws. The connection between the connecting plate 2311 and the connecting frame 23 is preferably made by screws. Therefore, the connecting plate 2311 has multiple holes for screws to pass through. The connection between the protrusion 2312 and the connecting plate 2311 is preferably made by integral molding or welding. The connection between the connecting rod 213, the mounting plate 214 and the slider 211 is preferably made by screws. Therefore, the mounting plate 214 has holes for screws to pass through. The slider 211 has screw holes. The connecting rod 213 is preferably made by welding to the mounting plate 214. The connecting rod 213 is welded to the mounting plate 214 perpendicular to the surface of the mounting plate 214.

[0057] Preferably, the bottom of the connecting frame 23 is located above the ground.

[0058] In practical applications, the relative position of the connecting frame 23 to the ground is mainly taken into account the transportation method of the Dewar canister.

[0059] In one embodiment, the Dewar canisters are individually hand-carried, allowing the operator to simply place them one by one into the filling station 24.

[0060] In one embodiment, the distance between the connecting frame 23 and the ground is used to accommodate the trolley. The Dewar cans are transported by trolley, that is, the Dewar cans are placed on the trolley and transported together. At this time, the Dewar cans are arranged in a row on the trolley. The operator first adjusts the spacing between the Dewar cans, and then pushes the trolley toward the fixed frame 22 in a direction perpendicular to the arrangement of the Dewar cans. At this time, each Dewar can enters the filling position 24.

[0061] In one embodiment, similar to the previous embodiment, a trolley is used, but the Dewar cans are not lined up in a row. In this case, the above operation is performed with the number of cans lined up in a row. The extra Dewar cans are placed separately in a filling position 24 for filling. After filling, they are moved to the trolley for transportation.

[0062] Example 2

[0063] Reference Figure 6 A liquid nitrogen filling method is disclosed, comprising a Dewar flask and a liquid nitrogen output pipeline. The liquid nitrogen output pipeline has a control valve, and the liquid nitrogen output end is connected to an external liquid nitrogen storage system for outputting liquid nitrogen. The method uses the liquid nitrogen filling system of Example 1, and the specific method is as follows:

[0064] Place plate 1 over the mouth of the Dewar canister, open the control valve, and introduce liquid nitrogen into the Dewar canister. At this time, observe the white mist discharge from the exhaust pipe 12. If the white mist decreases or disappears instantly, close the control valve and the filling is complete.

[0065] It should be noted that the liquid nitrogen storage system is prior art in this field, and those skilled in the art are well aware of its use in storing and discharging liquid nitrogen through liquid nitrogen output pipelines.

[0066] In this way, as the liquid nitrogen in the Dewar canister rises, the liquid nitrogen level gradually approaches the lower end of the vent pipe 12. When the liquid nitrogen level and the lower end of the vent pipe 12 reach a certain distance, a liquid seal effect is formed, and the white mist emitted from the vent pipe momentarily decreases or disappears. At this point, the liquid nitrogen level is the preset rated level for filling. The control valve is then closed, completing the filling process. Furthermore, regarding liquid level judgment, the "hissing" sound produced by the vaporization of liquid nitrogen is particularly noticeable when the liquid nitrogen level is close to the canister opening. In this embodiment, this sound can also be introduced for secondary judgment, improving the accuracy of liquid level determination.

[0067] Therefore, the exhaust pipe 12 serves three purposes: pressure relief, liquid level detection, and providing a handheld grip. The plate not only prevents splashing but also guides the direction of the white mist, preventing the white mist emanating from the tank opening from interfering with the operator's observation of the white mist in the exhaust pipe.

[0068] Example 3

[0069] In this embodiment, a flow meter is installed on the liquid nitrogen output pipeline, and a level gauge is installed on the plate 1.

[0070] Specifically, the exhaust pipe 12 of Embodiment 1 can be used as an auxiliary monitoring device for the liquid level inside the Dewar tank. In actual use, considering that the filling object is liquid nitrogen, a turbine flow meter is preferred; a guided wave radar level meter is preferred. The guided wave radar level meter is installed on the plate 1 using an installation method known to those skilled in the art. The judgment is made from multiple aspects by means of the flow meter, level meter, exhaust pipe and sound. Of course, a weighing device can also be set at the filling position of Embodiment 1 to introduce a weighing method for more accurate judgment.

Claims

1. A liquid nitrogen filling system, characterized in that, Includes: a plate body having a conveying pipe and an exhaust pipe; The delivery pipe is connected to the external liquid nitrogen output pipe, and the exhaust pipe is installed on the plate body in a manner that penetrates the plate body. The plate body is used to cover the opening of the external tank body and can completely cover the opening of the tank body. When the plate covers the can opening, the lower end of the vent pipe extends to the rated filling depth of the can.

2. The liquid nitrogen filling system according to claim 1, characterized in that, The liquid nitrogen filling system also includes a frame, which has an adjusting element for adjusting the position of the plate in the vertical direction; the plate is connected to the adjusting element.

3. The liquid nitrogen filling system according to claim 1, characterized in that, The plate is disc-shaped, and the axes of the plate, the exhaust pipe, and the conveying pipe are all vertically arranged. The conveying pipe passes through the plate. The length of the portion of the conveying pipe protruding from the upper surface of the plate is less than the length of the portion protruding from the lower surface of the plate, and the length of the portion of the conveying pipe protruding from the lower surface of the plate is greater than the length of the portion of the exhaust pipe protruding from the lower surface of the plate.

4. The liquid nitrogen filling system according to claim 3, characterized in that, The upper end of the delivery pipe has a threaded connector for threading a braided hose, and the delivery pipe is connected to an external liquid nitrogen output pipe through the braided hose.

5. The liquid nitrogen filling system according to claim 2, characterized in that, The frame includes a fixed frame and a connecting frame. The fixed frame is fixedly connected to the ground. There are multiple connecting frames, which are arranged at intervals along the length of the fixed frame. The connecting frames are fixedly connected to the fixed frame. The multiple connecting frames divide multiple filling positions for placing the can. Each filling position has a plate. The adjusting member is located on the connecting frame.

6. The liquid nitrogen filling system according to claim 5, characterized in that, The connecting frame has a slide rail facing the corresponding filling position. The slide rail is arranged vertically. The adjusting component includes a slider that matches the slide rail. A hand-tightening bolt is screwed onto the slider to lock the slider onto the slide rail. A connecting rod is also connected to the slider. One end of the connecting rod is connected to the slider through a mounting plate, and the other end is connected to the plate body, which is located in the vertical area of ​​the filling position.

7. The liquid nitrogen filling system according to claim 5, characterized in that, The bottom of the connecting frame is located above the ground.

8. The liquid nitrogen filling system according to claim 6, characterized in that, The slide rail includes a connecting plate, which is vertically arranged and connected to the side of the connecting frame facing the corresponding filling position. The surface of the connecting plate has a protrusion, and the protrusion has recesses on both sides along its length. The slider has a through groove that matches the protrusion. The slider is slidably connected to the protrusion through the through groove. One side of the slider has a threaded hole that communicates with the through groove. The threaded hole is used to screw the hand-tightening bolt.

9. A liquid nitrogen filling method, characterized in that, The method involves a Dewar flask and a liquid nitrogen output pipeline, the liquid nitrogen output pipeline having a control valve, the liquid nitrogen output pipeline being connected to an external liquid nitrogen storage system and used for outputting liquid nitrogen, the method employing a liquid nitrogen filling system as described in any one of claims 1 to 8, and the method specifically comprising: Place the plate over the mouth of the Dewar jar, open the control valve, and let liquid nitrogen into the Dewar jar. At this time, judge the liquid nitrogen level in the Dewar jar by observing the white mist coming out of the exhaust pipe. If the white mist decreases or disappears instantly, close the control valve; filling is now complete.

10. The liquid nitrogen filling method according to claim 9, characterized in that, The liquid nitrogen output pipeline is equipped with a flow meter, and the plate is equipped with a level gauge.

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