Method and device for quickly injecting liquid nitrogen

Abstract

The invention provides a liquid nitrogen rapid injection method and device, and relates to the technical field of liquid nitrogen refrigeration, and the method comprises the following steps: S1, installing a liquid nitrogen cup at a bottle opening of a Dewar flask, and enabling an injection opening at the bottom of the liquid nitrogen cup to be communicated with the bottle opening; and S2, after liquid nitrogen is injected into the liquid nitrogen cup, a cup opening of the liquid nitrogen cup is sealed, so that the liquid nitrogen in the liquid nitrogen cup is rapidly injected into the Dewar flask through the injection opening under the action of pressure generated by sealing. The liquid nitrogen injection device has the beneficial effects that the cup opening of the liquid nitrogen cup is sealed, liquid nitrogen in the liquid nitrogen cup can be naturally evaporated, and a high-pressure area is formed in the position close to the cup opening, so that the injection power of the liquid nitrogen is converted into pressure difference drive from gravity drive, and compared with a traditional gravity injection mode, the flow speed of the liquid nitrogen passing through the injection opening can be greatly increased; the liquid nitrogen injection time is effectively shortened, then liquid nitrogen supplementation of the Dewar liquid nitrogen cavity is rapidly completed, and the method is suitable for scenes with high requirements for injection efficiency such as low-temperature experiment emergency starting and equipment sudden low-temperature working conditions.

Description

Technical Field

[0001] This invention relates to the field of liquid nitrogen refrigeration technology, and in particular to a method and apparatus for rapid liquid nitrogen injection. Background Technology

[0002] The Dewar flask is the core container for ensuring cryogenic operation. Its internal liquid nitrogen chamber maintains the cryogenic state of liquid nitrogen through an insulation structure, and replenishing the liquid nitrogen chamber with liquid nitrogen is one of the routine operation and maintenance procedures for this type of equipment.

[0003] Currently, the most commonly used liquid nitrogen injection method in the industry is gravity natural injection. The specific operation process is usually as follows: the liquid nitrogen cup is directly attached to the mouth of the Dewar flask, so that the injection port at the bottom of the liquid nitrogen cup is connected to the mouth of the Dewar flask. Relying on the gravity of the liquid nitrogen itself, the liquid nitrogen in the liquid nitrogen cup flows naturally into the Dewar liquid nitrogen chamber of the Dewar flask to complete the replenishment of liquid nitrogen.

[0004] However, the aforementioned gravity-based natural injection method has significant technical drawbacks in practical applications: During the injection process, the Dewar liquid nitrogen chamber is a relatively enclosed space, typically at room temperature when not filled with liquid nitrogen. When liquid nitrogen is injected, the contact between the liquid nitrogen and the room-temperature chamber causes significant evaporation, and the resulting gaseous medium gradually accumulates within the Dewar liquid nitrogen chamber. Simultaneously, because the injection tube connecting the liquid nitrogen cup and the Dewar liquid nitrogen chamber is usually located directly at the bottle opening, the flow path to the outlet of the Dewar liquid nitrogen chamber is easily obstructed or restricted by the space provided by the injection tube. This prevents the gas generated by evaporation from being discharged smoothly and promptly, thus creating a certain internal pressure within the Dewar liquid nitrogen chamber. The internal air pressure creates a reverse resistance with the gravity injection force of liquid nitrogen in the liquid nitrogen cup, making it difficult for the liquid nitrogen in the liquid nitrogen cup to flow quickly into the Dewar liquid nitrogen chamber, resulting in a slow liquid nitrogen injection rate. Moreover, the long injection time will increase the evaporation loss of liquid nitrogen during the transfer process, further reducing the effective utilization rate of liquid nitrogen. The overall injection efficiency is low and cannot meet the requirements of some application scenarios with high liquid nitrogen injection speed. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a method for rapid liquid nitrogen injection, comprising: Step S1: Install the liquid nitrogen cup onto the mouth of the Dewar flask, so that the injection port at the bottom of the liquid nitrogen cup is connected to the mouth of the flask. Step S2: After injecting liquid nitrogen into the liquid nitrogen cup, seal the mouth of the liquid nitrogen cup so that the liquid nitrogen in the liquid nitrogen cup is quickly injected into the Dewar flask through the injection port under the pressure generated by the seal.

[0006] Preferably, the bottom of the liquid nitrogen cup is provided with a delivery pipe communicating with the injection port. When the liquid nitrogen cup is installed at the mouth of the Dewar flask, the delivery pipe enters the liquid nitrogen chamber of the Dewar flask from the mouth of the flask.

[0007] Preferably, in step S2, after liquid nitrogen is injected into the liquid nitrogen cup, the cup opening is sealed by placing a sealing cup lid on the cup opening.

[0008] Preferably, the sealing cup lid is a rubber cup lid.

[0009] Preferably, the liquid nitrogen cup is further provided with a support foot at the bottom. When the liquid nitrogen cup is installed at the mouth of the Dewar flask, the support foot supports the periphery of the mouth of the flask, so that there is a gap between the bottom of the liquid nitrogen cup and the mouth of the flask.

[0010] Preferably, the Dewar flask has an opening on its side, a sealing component is provided at the opening, and one end of the delivery pipe that enters the liquid nitrogen chamber is lower than the position of the opening.

[0011] Preferably, a through hole is provided between the top of the liquid nitrogen chamber and the bottle opening, and the diameter of the through hole is larger than the outer diameter of the delivery pipe.

[0012] The present invention also provides a liquid nitrogen rapid injection device, which is applied to the above-mentioned liquid nitrogen rapid injection method, including a liquid nitrogen cup, wherein the bottom of the liquid nitrogen cup is provided with an injection port, and the cup mouth cover of the liquid nitrogen cup is provided with a sealing component.

[0013] Preferably, the bottom of the liquid nitrogen cup is provided with a delivery pipe communicating with the injection port.

[0014] Preferably, the sealing component is a sealing cup lid.

[0015] The above technical solution has the following advantages or beneficial effects: 1) By sealing the mouth of the liquid nitrogen cup, the liquid nitrogen inside the cup will naturally evaporate and form a high-pressure area near the mouth. This high pressure can directly eliminate the back pressure generated by the evaporation of liquid nitrogen in the Dewar liquid nitrogen chamber, so that the liquid nitrogen injection power changes from gravity driving to pressure difference driving. Compared with the traditional gravity injection method, the flow rate of liquid nitrogen through the injection port can be greatly increased, effectively shortening the liquid nitrogen injection time, and thus quickly completing the liquid nitrogen replenishment of the Dewar liquid nitrogen chamber. It is suitable for scenarios with high requirements for injection efficiency, such as emergency start-up of low temperature experiments and sudden low temperature conditions of equipment. 2) Rapid injection of liquid nitrogen significantly shortens the exposure time of liquid nitrogen during the transfer process, reducing liquid nitrogen evaporation loss during the injection stage. Furthermore, the pressure differential driving method can fully utilize... The liquid nitrogen in the liquid nitrogen cup is pushed into the Dewar liquid nitrogen chamber, avoiding liquid nitrogen residue caused by back pressure obstruction during gravity injection, and effectively improving the effective utilization rate of liquid nitrogen; 3) The pressure can be generated by the evaporation of liquid nitrogen itself simply by sealing the mouth of the liquid nitrogen cup. There is no need to configure additional auxiliary equipment such as pressurizing pumps and pressure regulating valves. The operation process is simple and easy to implement, and saves the purchase and maintenance costs of additional equipment. Moreover, the pressure generated by the seal comes from the natural evaporation of liquid nitrogen, and the pressure intensity is controllable. There will be no over-pressurization, which balances the convenience of operation and the safety of use. Attached Figure Description

[0016] Figure 1 A schematic flowchart of a rapid liquid nitrogen injection method is shown in a preferred embodiment of the present invention. Figure 2 A schematic diagram of the structure of the liquid nitrogen cup installed at the mouth of the Dewar flask in a preferred embodiment of the present invention; In the diagram: 1. Dewar flask; 2. Liquid nitrogen cup; 3. Inlet; 4. Delivery pipe; 5. Liquid nitrogen chamber; 6. Sealed cup lid; 7. Support foot; 8. Opening; 9. Test chamber; 10. Through hole; 11. Substrate. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment; other embodiments that conform to the spirit of the present invention may also fall within the scope of the present invention.

[0018] In a preferred embodiment of the present invention, based on the above-mentioned problems existing in the prior art, a method for rapid liquid nitrogen injection is provided, such as... Figure 1 As shown, it includes: Step S1: Install the liquid nitrogen cup onto the mouth of the Dewar flask, so that the injection port at the bottom of the liquid nitrogen cup is connected to the mouth of the flask. Step S2: After injecting liquid nitrogen into the liquid nitrogen cup, seal the mouth of the liquid nitrogen cup so that the liquid nitrogen in the liquid nitrogen cup can be quickly injected into the Dewar flask through the injection port under the pressure generated by the seal.

[0019] Specifically, this invention is mainly applied to low-temperature operating condition protection. For example, when it is necessary to test an infrared cooling chip under low-temperature conditions, it can be achieved through methods such as... Figure 2 The Dewar flask 1 shown is filled with liquid nitrogen to provide cryogenic protection, and the liquid nitrogen inside is promptly emptied after the test. However, the mouth of Dewar flask 1 is relatively small, making it difficult to directly inject liquid nitrogen. In this embodiment, as... Figure 2 As shown, liquid nitrogen is injected using a liquid nitrogen cup 2 with a large opening. When liquid nitrogen injection is required, the liquid nitrogen cup 2 is first installed at the mouth of the Dewar flask 1, so that the injection port 3 at the bottom of the liquid nitrogen cup 1 is connected to the mouth of the flask.

[0020] Furthermore, the bottom of the liquid nitrogen cup 2 is provided with a delivery pipe 4 that communicates with the injection port 3. When the liquid nitrogen cup 2 is installed at the mouth of the Dewar flask 1, the delivery pipe 4 enters the liquid nitrogen chamber 5 of the Dewar flask 1 from the mouth. The Dewar flask 1 has an opening 8 on its side, and a test chamber 9 with an embedded substrate 11 is provided at the opening 8. If it is necessary to test the infrared cooling chip under low temperature conditions, the infrared cooling chip can be attached to the side of the substrate 11 away from the opening, and then liquid nitrogen is injected into the Dewar flask 1 to provide a low temperature for the substrate 11, thereby providing low temperature protection for the infrared cooling chip.

[0021] Specifically, in this embodiment, by designing a delivery pipe 4 to enter the liquid nitrogen chamber 5, after the liquid nitrogen cup 1 is installed, a certain amount of liquid nitrogen (e.g., ...) can be injected into the mouth of the liquid nitrogen cup 1. Figure 2 In area B shown, the liquid nitrogen level in liquid nitrogen cup 1 is not limited each time it is injected (only a certain level difference between the liquid nitrogen level and the cup opening is required). Then, the cup opening is sealed by placing a sealing cap 6 on the liquid nitrogen cup 2. The liquid nitrogen in liquid nitrogen cup 1 will naturally evaporate and... Figure 2 As shown, area A forms a high-pressure zone. This high pressure directly counteracts the back pressure generated by liquid nitrogen evaporation within the Dewar liquid nitrogen chamber 5, changing the injection power from gravity-driven to pressure difference-driven. Compared to traditional gravity injection, this significantly increases the flow rate of liquid nitrogen through the injection port, effectively shortening the injection time and rapidly replenishing the Dewar liquid nitrogen chamber. This is suitable for scenarios with high injection efficiency requirements, such as emergency start-up of cryogenic experiments and sudden low-temperature conditions of equipment. Furthermore, the rapid injection of liquid nitrogen significantly reduces the exposure time during transfer, minimizing liquid nitrogen evaporation loss during injection. Additionally, the pressure difference-driven method effectively pushes the liquid nitrogen from the liquid nitrogen cup into the Dewar liquid nitrogen chamber, avoiding liquid nitrogen residue caused by back pressure during gravity injection and effectively improving the utilization rate of liquid nitrogen. Furthermore, the pressure can be generated by the evaporation of liquid nitrogen itself simply by sealing the mouth of the liquid nitrogen cup, without the need for additional auxiliary equipment such as pressurizing pumps and pressure regulating valves. The operation process is simple and easy to implement, while saving the purchase and maintenance costs of additional equipment. Moreover, the pressure generated by the seal comes from the natural evaporation of liquid nitrogen, and the pressure intensity is controllable, preventing over-pressurization and balancing ease of operation and safety of use.

[0022] Among them, the sealing cup lid 6 is a rubber cup lid. The rubber material has good elastic deformation ability and can closely fit the contour of the cup mouth of the liquid nitrogen cup 2 to ensure the sealing reliability of the cup mouth. At the same time, the rubber cup lid does not require additional fastening parts, making it easy to operate and inexpensive, and can stably maintain the pressure environment inside the liquid nitrogen cup.

[0023] In a preferred embodiment of the present invention, the bottom of the liquid nitrogen cup 2 is further provided with a support foot 7. When the liquid nitrogen cup 2 is installed at the mouth of the Dewar flask 1, the support foot 7 supports the periphery of the mouth of the flask, so that there is a gap between the bottom of the liquid nitrogen cup 2 and the mouth of the flask.

[0024] Specifically, in this embodiment, when the liquid nitrogen cup 2 is installed at the mouth of the Dewar flask 1, the support foot 7 can stably support the outer area of ​​the mouth, forming a preset gap between the bottom of the liquid nitrogen cup 2 and the mouth. This gap provides a gas overflow channel for the liquid nitrogen chamber 5 of the Dewar flask 1. During the liquid nitrogen injection process, the liquid nitrogen in the liquid nitrogen chamber 5 will continuously evaporate to generate a gaseous medium. This gas can be smoothly discharged to the outside through the gap between the bottom of the cup and the mouth, avoiding the accumulation of gas in the liquid nitrogen chamber 5, which could lead to problems such as... Figure 2 The back pressure in area C is too high, which ensures that the high pressure inside liquid nitrogen cup 2 can form a stable pressure difference to drive the rapid injection of liquid nitrogen. At the same time, this gap can also prevent the bottom of the cup from directly contacting the bottle mouth, which would cause the injection port to be blocked or clogged. It also provides operating space for the precise docking of the injection port and the bottle mouth, significantly improving the ease of assembly and connection stability. Furthermore, a through hole 10 is provided between the top of the liquid nitrogen chamber 5 of the Dewar flask and the bottle mouth, and the diameter of the through hole 10 is larger than the outer diameter of the subsequent delivery pipe 4: this through hole and the above-mentioned gap form a dual gas flow channel, which further enhances the discharge effect of the gas generated by the evaporation of liquid nitrogen in the liquid nitrogen chamber 5. Even if the gap is partially blocked due to assembly deviation, the through hole 10 can still ensure smooth gas flow and minimize the impact of back pressure on the injection rate.

[0025] The present invention also provides a liquid nitrogen rapid injection device, which is applied to the above-mentioned liquid nitrogen rapid injection method, including a liquid nitrogen cup, an injection port at the bottom of the liquid nitrogen cup, and a sealing component on the cup mouth cover.

[0026] In a preferred embodiment of the present invention, the bottom of the liquid nitrogen cup is provided with a delivery pipe communicating with the injection port.

[0027] In a preferred embodiment of the present invention, the sealing component is a sealing cup lid.

[0028] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present invention.

Claims

1. A method for rapid liquid nitrogen injection, characterized in that, include: Step S1: Install the liquid nitrogen cup onto the mouth of the Dewar flask, so that the injection port at the bottom of the liquid nitrogen cup is connected to the mouth of the flask. Step S2: After injecting liquid nitrogen into the liquid nitrogen cup, seal the mouth of the liquid nitrogen cup so that the liquid nitrogen in the liquid nitrogen cup is quickly injected into the Dewar flask through the injection port under the pressure generated by the seal.

2. The rapid liquid nitrogen injection method according to claim 1, characterized in that, The bottom of the liquid nitrogen cup is provided with a delivery pipe that communicates with the injection port. When the liquid nitrogen cup is installed at the mouth of the Dewar flask, the delivery pipe enters the liquid nitrogen chamber of the Dewar flask through the mouth of the flask.

3. The rapid liquid nitrogen injection method according to claim 1, characterized in that, In step S2, after liquid nitrogen is injected into the liquid nitrogen cup, the cup opening is sealed by placing a sealing cup lid on the cup opening.

4. The rapid liquid nitrogen injection method according to claim 3, characterized in that, The sealing cup lid is a rubber cup lid.

5. The rapid liquid nitrogen injection method according to claim 1, characterized in that, The liquid nitrogen cup is also provided with a support foot at the bottom. When the liquid nitrogen cup is installed at the mouth of the Dewar flask, the support foot supports the periphery of the mouth of the flask so that there is a gap between the bottom of the liquid nitrogen cup and the mouth of the flask.

6. The rapid liquid nitrogen injection method according to claim 2, characterized in that, The bottom outer side of the Dewar flask is provided with a test cavity, and a base plate is installed inside the test cavity; The bottom side of the Dewar flask has an opening that communicates with the liquid nitrogen chamber, and the base plate is fixed to the opening.

7. The rapid liquid nitrogen injection method according to claim 2, characterized in that, A through hole is provided between the top of the liquid nitrogen chamber and the bottle opening, and the diameter of the through hole is larger than the outer diameter of the delivery pipe.

8. A liquid nitrogen rapid injection device, characterized in that, The liquid nitrogen rapid injection method according to any one of claims 1-7 includes a liquid nitrogen cup, wherein the bottom of the liquid nitrogen cup is provided with an injection port, and the cup mouth cap of the liquid nitrogen cup is provided with a sealing component.

9. The liquid nitrogen rapid injection device according to claim 8, characterized in that, The bottom of the liquid nitrogen cup is provided with a delivery pipe that communicates with the injection port.

10. The liquid nitrogen rapid injection device according to claim 8, characterized in that, The sealing component is a sealing cup lid.

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