JPH0723828B2 - Low temperature heat transfer flexible tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to the cold heat of a cryogenic refrigerator for preventing evaporation of liquid nitrogen used in a magnetic shield for high temperature superconductivity, an electron microscope, a nuclear magnetic resonance apparatus and the like. Low temperature heat transfer pipe for transporting hydrogen to a liquid nitrogen storage.

<< Prior Art >> In general, liquid nitrogen is used as a cooling medium in a magnetic shield part in high temperature superconductivity, an electron microscope, or each magnetic resonance apparatus. In the past, the cold heat generated in the cryogenic refrigerator was transported to the liquid nitrogen tank of the cooled part to prevent the evaporation of liquid nitrogen, but this cold heat transport method uses high-pressure helium gas. Conventional circulation system, cryogenic refrigerator and liquid nitrogen storage tank's cooled part connected by a short heat transfer pipe, vibration isolation type short-distance heat transfer system under common vacuum insulation, cryogenic refrigerator in liquid nitrogen storage tank There was a direct cooling system, etc.

<Problems to be Solved> However, the high-pressure helium gas circulation system has problems that the heat transfer efficiency is low, the device becomes large and expensive, and high-frequency vibration due to pump compression is transmitted to the cooled part. In addition, the direct cooling method and the vibration-proof short-distance heat transfer method are uncertain in the removal of vibration, and are affected by the operating noise of the refrigerator and the generation of extremely small leakage magnetic fields due to the operation of the refrigerator motor. There was a problem that it appeared in the cooling section.

The present invention has been made paying attention to such a point, without transmitting the vibration of the refrigerator or the like to the cooled portion, and
An object is to provide a cold heat transfer pipe capable of transporting cold heat with high cold heat transport efficiency.

<< Means for Solving the Problem >> In order to achieve the above object, the present invention provides a refrigerator-side joint block that is thermally connected to a cold heat generating portion of a cryogenic refrigerator, and a cooled portion that is arranged in a cooled portion. The side joint block, the heat transfer member connecting both blocks, the outer pipe covering the outer periphery of the heat transfer member, and the heat insulating material filled between the heat transfer member and the outer pipe, The heat transfer member and the outer tube are composed of a copper mesh wire braided with thin copper wires, the outer tube is made of a flexible material having heat insulation properties, and the heat insulating material is made by mixing a powder heat insulating material with a moisture adsorbent. It is characterized in that the powder is vacuum-insulated between and.

<< Operation >> In the present invention, a refrigerator-side joint block that is thermally connected to the cold heat generating portion of the cryogenic refrigerator, a cooled portion-side joint block that is arranged in the cooled portion, and a heat transfer member that connects both blocks,
An outer tube that covers the outer periphery of the heat transfer member, and a heat insulating material filled between the heat transfer member and the outer tube. The heat transfer member is configured by a copper mesh wire woven with thin copper wire, and the outer tube is It is composed of a composite material of a polymer film and an aluminum foil or a flexible material having heat insulating properties such as rubber, and the heat insulating material is formed by mixing a powder heat insulating material with a moisture adsorbent, and a heat transfer member and an outer tube. Since it is formed so as to be vacuum-insulated between the powders, the efficiency of transporting cold heat from the refrigerator to the cooled portion can be improved, and the heat transfer member and the outer tube have flexibility. The vibration on the refrigerator side is not transmitted to the cooled part.

<< Examples >> The drawings show examples of the present invention. FIG. 1 is a partially cutaway vertical sectional view of a low temperature heat transfer tube, and FIG. 2 is a schematic configuration diagram showing an example of its use.

This low-temperature heat transfer pipe connects both blocks to a refrigerator-side joint block (1) that is thermally connected to a cold heat generating portion of a cryogenic refrigerator, and a cooled portion joint block (2) that is arranged in a cooled portion. It is composed of a heat transfer member (3), an outer tube (4) covering the outer periphery of the heat transfer member, and a heat insulating material (5) filled between the heat transfer member and the outer tube.

The heat transfer member (3) is composed of a copper mesh wire formed by knitting a plurality of thin copper wires, and one end of the heat transfer member (3) is connected to the refrigerator side joint block (1).
Of the heat exchange fins (7) of the joint block (2) to be cooled. The heat transfer member (3) is bound in the longitudinal direction at regular intervals with a binding thread (8) such as glass fiber, nylon thread, or Teflon thread, and is kept in contact with the inner surface of the outer tube (4). Contact prevention spacers (9) are attached at regular intervals.

The outer tube (4) is composed of a composite material of a polymer film and an aluminum foil, or a flexible material having heat insulation and airtightness such as rubber.

The heat insulating material (5) is composed of a powder heat insulating material such as pearlite or a sand cell mixed with a water adsorbent such as silica gel alumina gel.

Therefore, the cryogenic transfer tube is entirely flexible.

And two vacuum and safety valves (10) are provided at the connection between the exterior pipe (4) and the refrigerator side joint block (1),
One vacuum and safety valve (10a) communicates with the gap between the outer tube (4) and the heat transfer member (3), that is, the heat insulating material (5) layer. The powder vacuum insulation is used, and the other vacuum and safety valve (10b) is used for the cold heat generation part (12) and the refrigerator side when the refrigerator side joint block (1) is connected to the cryogenic refrigerator (11). Joint block (1)
It communicates with the space between and, and is designed to form a vacuum in this space.

Fig. 2 shows the case of cooling the high-temperature superconducting magnetic shield plate of the squid, in which the refrigerator side joint side block (1) of the low temperature heat transfer pipe is connected to the cold heat generation part (12) of the cryogenic refrigerator (11). The block (2) to be cooled is connected to the liquid nitrogen storage tank (14) of the heat insulating container (13). In FIG. 2, reference numeral (15) is a magnetic shield plate arranged in the liquid nitrogen storage tank (14), (16) is an automatic operation measuring instrument, and the automatic operation measuring instrument (16) is a liquid nitrogen storage tank. Liquid level gauge (17) for detecting liquid level in (14), thermometer (18) for detecting temperature in liquid nitrogen storage tank (14), pressure for detecting pressure in liquid nitrogen storage tank (14) It consists of a total of (19), safety valves, etc.

FIG. 3 shows another embodiment in which a rigid heat transfer member (20) is arranged inside the outer tube (4), and the rigid heat transfer member (20) and the refrigerator side joint block (1) are connected to each other. And the rigid body heat transfer member (20) and the cooled part joint block (2) are connected by a copper mesh wire heat transfer member (3), which is different from the low temperature transfer pipe. The point that the heat transfer member (3) made of wire wire is bound by the glass fiber (8), the contact prevention spacer (9) is attached to the heat transfer member (3) made of copper wire, etc. It is similarly configured. Therefore, in the low temperature transfer pipe of this embodiment, both side portions sandwiching the rigid body heat transfer member (20), that is, the portions connected by the copper mesh wire heat transfer member (3) have flexibility. The outer tube (4) at the portion corresponding to the rigid heat transfer member (20) does not have to have flexibility.

In the low-temperature transmission pipe configured as described above, since the entire transmission pipe or at least two places has flexibility, the piping becomes easy, and the vibration accompanying the operation of the cryogenic refrigerator is generated by this transmission pipe. Since the flexible portion absorbs the vibration, the vibration is not transmitted to the cooled portion. In addition, the cold heat is transferred to the part to be cooled by the heat transfer member made of copper wire,
Insulate the low temperature heat transfer tube by binding the heat transfer member made of copper mesh wire with a binding thread, installing spacers for preventing contact at regular intervals, and filling the heat transfer member and the outer tube with a heat insulating material. Since the heat transfer member does not come into contact with the exterior pipe even if the pipe is curved, the heat transfer efficiency is kept high.

<< Effects >> In the present invention, a refrigerator side joint block that is thermally connected to the cold heat generating portion of the cryogenic refrigerator, a cooled portion side joint block that is arranged in the cooled portion, and a heat transfer member that connects both blocks,
An outer tube that covers the outer periphery of the heat transfer member, and a heat insulating material filled between the heat transfer member and the outer tube. The heat transfer member is configured by a copper mesh wire woven with thin copper wire, and the outer tube is It is composed of a composite material of a polymer film and an aluminum foil or a flexible material having heat insulating properties such as rubber, and the heat insulating material is formed by mixing a powder heat insulating material with a moisture adsorbent, and a heat transfer member and an outer tube. Since it is formed so as to be vacuum-insulated between the powders, the efficiency of transporting cold heat from the refrigerator to the cooled portion can be improved, and the heat transfer member and the outer tube have flexibility. It is possible to prevent the vibration on the refrigerator side from being transmitted to the cooled portion.

[Brief description of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a vertical cross-sectional view of a low temperature heat transfer pipe, FIG. 2 is a schematic configuration diagram showing an example of its use, and FIG. 3 is a first embodiment of another embodiment. FIG. 1 ... Refrigerator side joint block, 2 ... Cooled part joint block, 3 ... Heat transfer member, 4 ... Exterior tube, 5 ... Insulating material, 8 ... Bundling thread, 9 ... Contact prevention spacer ,Ten……
Evacuation and safety valve, 11 ... Cryogenic refrigerator, 12 ... Cold heat generating part, 13 ... Cooled part (insulated container), 20 ... Rigid heat transfer member.

Claims (4)

[Claims] Claim: What is claimed is: 1. A heat transfer pipe for transporting refrigeration heat generated by a cryogenic refrigerator arranged apart from a cooled portion to the cooled portion, the refrigeration being thermally connected to a cold heat generating portion of the cryogenic refrigerator. A machine side joint block, a cooled part side joint block arranged in a cooled part, a heat transfer member connecting both blocks, an outer pipe covering the outer periphery of the heat transfer member, a heat transfer member and an outer pipe. The heat transfer member is composed of a copper mesh wire woven with thin copper wire, the outer pipe is composed of a flexible material having heat insulation property, and the heat insulation material is a powder insulation material and moisture. Flexible tube for low temperature heat transfer, characterized in that it is constituted by mixing an adsorbent, and powder heat insulation between the heat transfer member and the outer tube is performed. 2. A copper mesh wire heat transfer member is bound by a binding thread at regular intervals in the longitudinal direction, and contact prevention spacers are arranged at regular intervals in the longitudinal direction between the heat transfer member and the outer tube. The low temperature heat transfer flexible tube according to claim 1. 3. A rigid heat transfer member is arranged in the outer tube, and the rigid heat transfer member is connected to the refrigerator side joint block and the cooled portion side joint block by a copper mesh wire heat transfer member. Low temperature heat transfer flexible tube according to 2. 4. The vacuuming and safety valve is arranged at a connecting portion between the heat transfer member and the outer tube and a connecting portion of the refrigerating machine side coupling block to the refrigerating machine output portion. Low temperature heat transfer flexible tube