Thermal insulation device for liquid nitrogen low-temperature instrument

Abstract

The utility model relates to the technical field of low-temperature heat preservation devices, in particular to a liquid helium low-temperature instrument heat preservation device which comprises a heat preservation box, the heat preservation box is sequentially provided with a liquid helium tank, an inner vacuum layer, an inner heat insulation layer, a liquid nitrogen layer, a middle heat insulation layer, an outer vacuum layer and an outer heat insulation layer from inside to outside, a sample basket is arranged in the liquid helium tank, and a sample is arranged in the sample basket. According to the low-temperature device adopting liquid helium for refrigeration, the lowest temperature reaches 269 DEG C, the excellent heat preservation performance of the heat preservation device is ensured, the loss of liquid helium is greatly reduced, and the use cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of low-temperature insulation devices, and in particular to an insulation device for a liquid nitrogen cryostat. Background Technology

[0002] Materials used in various mechanical equipment are generally made of metal. Improper selection or use of metal can lead to premature material failure, potentially causing serious accidents. As a crucial aspect of quality control in the machinery industry, the testing of raw materials, semi-finished products, and finished products before use is becoming increasingly important. With the continuous development of my country's economy, the country is placing greater emphasis on material requirements and the statistical analysis of test data. Especially in recent years, my country's vigorous development of the nuclear industry and aerospace has further demanded higher standards for the performance and data of special materials under harsh environments in research and manufacturing.

[0003] Currently available cryogenic impact testers using liquid nitrogen cooling can only reach a minimum temperature of -196℃, and have poor insulation performance, high liquid helium loss, and high cost. They also cannot meet the requirements for even lower temperatures. Therefore, it is necessary to propose an improvement to overcome the shortcomings of the existing technology. Utility Model Content

[0004] The purpose of this invention is to solve the problems in the prior art by providing a liquid nitrogen cryogenic instrument insulation device, which solves the problems of unsatisfactory cooling temperature and high cost of existing cryogenic insulation instruments.

[0005] The technical solution of this utility model is:

[0006] A liquid nitrogen cryogenic instrument insulation device includes an insulation box, which is provided from the inside out with a liquid helium tank, an inner vacuum layer, an inner heat insulation layer, a liquid nitrogen layer, a middle heat insulation layer, an outer vacuum layer and an outer heat insulation layer. A sample basket is provided inside the liquid helium tank, and a sample is provided inside the sample basket.

[0007] As a preferred technical solution, the insulated box is equipped with a liquid helium inlet and a liquid helium outlet, both of which are connected to the liquid helium tank.

[0008] As a preferred technical solution, the insulation box is provided with an external vacuum layer extraction port, and an external vacuum layer valve is provided on the connecting pipe of the external vacuum layer extraction port, and the external vacuum layer extraction port is connected to the external vacuum layer.

[0009] As a preferred technical solution, the insulation box is provided with an internal vacuum extraction port, and an internal vacuum layer valve is provided on the connecting pipe of the internal vacuum extraction port, and the internal vacuum extraction port is connected to the internal vacuum layer.

[0010] As a preferred technical solution, the insulated box is provided with a liquid nitrogen layer inlet, which is connected to the liquid nitrogen layer.

[0011] As a preferred technical solution, a tank cover is provided above the liquid helium tank, and the tank cover is sealed to the liquid helium tank.

[0012] As a preferred technical solution, the lower end of the tank cover is provided with a heat-insulating baffle, which is located above the liquid helium tank.

[0013] As a preferred technical solution, the lower end of the tank cover is provided with a partition plate that extends into the liquid helium tank, dividing the liquid helium tank into an inlet tank and a sample placement tank. The bottoms of the inlet tank and the sample placement tank are connected. The sample basket is placed in the sample placement tank, and the connecting pipe of the liquid helium inlet extends into the inlet tank.

[0014] As a preferred technical solution, the slot cover is provided with a handle.

[0015] The beneficial effects of this utility model are:

[0016] This utility model discloses a liquid nitrogen cryogenic instrument insulation device. By setting up an insulation box, the insulation box is arranged from the inside out as follows: liquid helium tank, inner vacuum layer, inner heat insulation layer, liquid nitrogen layer, middle heat insulation layer, outer vacuum layer, and outer heat insulation layer. A sample basket is set up in the liquid helium tank, and the sample is placed in the sample basket. The cryogenic device using liquid helium cooling achieves a minimum temperature of 269℃, ensuring excellent insulation performance of the insulation device, greatly reducing liquid helium loss, and lowering the operating cost. Attached Figure Description

[0017] Figure 1 This is a perspective view of the liquid nitrogen cryostat insulation device of this utility model.

[0018] Figure 2 This is a schematic diagram of the internal structure of the liquid nitrogen cryogenic instrument insulation device of this utility model.

[0019] In the diagram: 1. Insulating partition; 2. Liquid helium outlet; 3. Sample basket; 4. Sample; 5. Outer vacuum layer valve; 6. Outer vacuum layer evacuation port; 7. Inner vacuum layer valve; 8. Inner vacuum layer evacuation port; 9. Liquid helium inlet; 10. Liquid nitrogen inlet; 11. Handle; 12. Tank cover; 13. Liquid helium tank; 14. Inner vacuum layer; 15. Inner insulation layer; 16. Liquid nitrogen layer; 17. Middle insulation layer; 18. Outer vacuum layer; 19. Outer insulation layer; 20. Partition. Detailed Implementation

[0020] To make the technical means, technical features, utility model purpose and technical effects of this utility model easier to understand, the present utility model will be further described below with reference to specific illustrations.

[0021] Example 1:

[0022] like Figure 1 The diagram shown is a schematic representation of the internal structure of the liquid nitrogen cryogenic instrument insulation device of this invention.

[0023] The cryogenic device for liquid nitrogen in this embodiment includes a cryogenic chamber, which is divided into multiple layers, from the inside out: a liquid helium tank 13, an inner vacuum layer 14, an inner insulation layer 15, a liquid nitrogen layer 16, a middle insulation layer 17, an outer vacuum layer 18, and an outer insulation layer 19. Multiple sample baskets 3 are installed inside the liquid helium tank 13, which are used to hold samples 4. Liquid helium is introduced into the liquid helium tank 13 for storing samples 4 and serving as a freezing chamber. The cryogenic chamber has a liquid helium inlet 9 and a liquid helium outlet 2. The liquid helium inlet 9 is located at the bottom of the cryogenic chamber, and the liquid helium outlet 9 is located at the top. Both the liquid helium inlet 9 and the liquid helium outlet 2 are connected to the liquid helium tank 13, and control valves are installed on the connecting pipes of the liquid helium inlet 9 and the liquid helium outlet 2 to control the flow of liquid helium into and out of the liquid helium tank 13. A partition 20 is fixed to the lower end of the tank cover 12. When the tank cover 12 is installed on the body of the insulated box, the partition 20 extends downward into the liquid helium tank 13. The partition 20 divides the liquid helium tank 13 into an inlet tank and a sample placement tank. The bottom of the inlet tank and the sample placement tank are connected. The connecting pipe of the liquid helium inlet 9 extends into the inlet tank. The liquid helium outlet 2 is located at the upper end of the inlet tank. The sample is placed in the sample placement tank. The inlet tank and the sample placement tank are separated, which ensures the stability of the temperature in the sample placement tank and better ensures the effect of the sample freezing experiment.

[0024] The upper end of the insulated box is sealed with a slot cover 12, which is detachably connected to the box body. The lower end of the slot cover 12 is fixedly installed with an insulation partition 1. When the slot cover 12 is installed on the box body of the insulated box, the insulation partition 1 is sealed to the liquid helium tank 13 for heat preservation of the liquid helium tank 13.

[0025] A handle 11 is fixed to the upper end of the slot cover 12 to facilitate the removal and placement of the slot cover 12.

[0026] The insulation box has an inner vacuum layer extraction port 8, which is connected to an inner vacuum layer 14 via a connecting pipe. An inner vacuum layer valve 7 is installed on the connecting pipe of the inner vacuum layer extraction port 8 to control the vacuuming of the inner vacuum layer 14. The insulation box also has an outer vacuum extraction port 6, which is connected to an outer vacuum layer 18 via a connecting pipe. An outer vacuum layer valve 5 is installed on the connecting pipe of the outer vacuum extraction port 6 to control the vacuuming of the outer vacuum layer 18. The inner vacuum layer 14 and the outer vacuum layer 18 are both under a vacuum of no more than 5 Pa, achieving vacuum insulation.

[0027] The inner insulation layer 15, the middle insulation layer 17 and the outer insulation layer 19 are all filled with low-temperature insulation material for the overall insulation of the insulated box.

[0028] The insulated box is equipped with a liquid nitrogen inlet 10. The connecting pipe of the liquid nitrogen inlet 10 is connected to the liquid nitrogen layer 16. A control valve is installed on the connecting pipe of the liquid nitrogen inlet 10 to control the nitrogen filling operation of the liquid nitrogen layer 16 for the insulation operation of the insulated box.

[0029] The inner vacuum layer evacuation port 8, outer vacuum evacuation port 6, liquid helium inlet 9, and liquid nitrogen layer inlet 10 of this invention are led out from the bottom of the insulation box, while the liquid helium outlet 2 is led out from the top of the insulation box to discharge the evaporated helium. Before use, the air in the vacuum layer is first evacuated through the vacuum evacuation port to create a vacuum, and the valve is closed to maintain a long-term vacuum in the vacuum layer. During use, first open the tank cover 12 and place the sample basket 3 and sample 4 inside. Liquid nitrogen is introduced into the liquid nitrogen layer 16 through the liquid nitrogen layer inlet 10 to lower the temperature of the insulation layer; then liquid helium is introduced through the liquid helium inlet 9, lowering the temperature inside the liquid helium tank to freeze the sample. After the freezing time is reached, open the tank cover 12 and remove the sample 4 for impact testing.

[0030] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. All equivalent changes and modifications made in accordance with the scope of the claims of this utility model should fall within the technical scope of this utility model.

Claims

1. A liquid nitrogen cryogenic instrument heat preservation device comprising a heat preservation box, characterized in that, The heat preservation box is sequentially provided with a liquid helium tank (13), an inner vacuum layer (14), an inner thermal insulation layer (15), a liquid nitrogen layer (16), a middle thermal insulation layer (17), an outer vacuum layer (18) and an outer thermal insulation layer (19) from inside to outside.

2. The liquid nitrogen cryogenic apparatus warming device of claim 1, wherein, The heat preservation box is provided with a liquid helium inlet (9) and a liquid helium outlet (2), and the liquid helium inlet (9) and the liquid helium outlet (2) are communicated with the liquid helium tank (13).

3. The liquid nitrogen cryogenic apparatus warming device of claim 1, wherein, The heat preservation box is provided with an outer vacuum layer exhaust port (6), and an outer vacuum layer valve (5) is arranged on the connecting pipe of the outer vacuum layer exhaust port (6), and the outer vacuum layer exhaust port (6) is communicated with the outer vacuum layer (18).

4. The liquid nitrogen cryogenic apparatus warming device of claim 1, wherein, The heat preservation box is provided with an inner vacuum layer exhaust port (8), and an inner vacuum layer valve (7) is arranged on the connecting pipe of the inner vacuum layer exhaust port (8), and the inner vacuum layer exhaust port (8) is communicated with the inner vacuum layer (14).

5. The liquid nitrogen cryogenic apparatus warming device of claim 1, wherein, The heat preservation box is provided with a liquid nitrogen layer inlet (10), and the liquid nitrogen layer inlet (10) is communicated with the liquid nitrogen layer (16).

6. The liquid nitrogen cryogenic apparatus holding device according to claim 2, wherein The upper portion of the liquid helium tank (13) is provided with a tank cover (12), and the tank cover (12) is sealingly connected with the liquid helium tank (13).

7. The liquid nitrogen cryogenic apparatus holding device according to claim 6, wherein The lower end of the tank cover (12) is provided with a thermal insulation partition plate (1), and the thermal insulation partition plate (1) is arranged above the liquid helium tank (13).

8. The liquid nitrogen cryogenic apparatus holding device according to claim 6, wherein The lower end of the tank cover (12) is provided with a partition plate (20), and the partition plate (20) extends into the liquid helium tank (13) to divide the liquid helium tank (13) into a liquid inlet tank and a sample placing tank, and the bottom portions of the liquid inlet tank and the sample placing tank are communicated, the sample basket (3) is arranged in the sample placing tank, and the connecting pipe of the liquid helium inlet (9) extends into the liquid inlet tank.

9. The liquid nitrogen cryogenic apparatus warming device of claim 6, wherein, The tank cover (12) is provided with a handle (11).

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