JPH04143597A - Flexible low-temperature heat transfer tube - Google Patents

Abstract

PURPOSE:To transport cold heat with a high cold heat transporting efficiency by a method wherein the title tube is constituted of a heat transfer member, an outer tube and heat insulating material filled into a space between the heat transfer member and the outer tube while the heat insulation of the space between the heat transfer member and the outer tube is effected through powder vacuum insulation. CONSTITUTION:A low-temperature heat transfer tube is constituted of a refrigerating machine side joint block 1, connected thermally to a cold heat generating unit of a cryogenic refrigerating machine, a cooled part joint block 2, arranged at a cooled part, a heat transfer member 3, connecting both blocks, an outer tube 4, covering the outer periphery of the heat transfer member, and heat insulating material 5, filled into a space between the heat transfer member 3 and the outer tube 4. The heat transfer member 3 is constituted of a copper braided wire, braided by a plurality of fine copper wires. The heat transfer member 3 is bound by binding threads 8 at every given intervals in the lengthwise direction of the same while contact preventing spacers 9 are attached to the wire in order not to contact the wire with the inner surface of the outer tube 4. The outer tube 4 is constituted of a flexible material having adiabatic property and air-tightness while the heat insulating material 5 is constituted of an adiabatic material mixed with moisture adsorbing agent and a space between the heat transfer member 3 and the outer tube 4 is filled with powder to insulate heat through powder vacuum heat insulation.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to the cooling of cryogenic refrigerators in order to prevent the evaporation of liquid nitrogen used in high-temperature superconducting magnetic coils, electron microscopes, nuclear magnetic resonance apparatuses, etc. The present invention relates to a low temperature heat transfer tube for transporting liquid nitrogen to a liquid nitrogen storage area.

(Prior Art) Generally, liquid nitrogen is used as a cooling medium in a magnetic shield unit, an electron microscope, or each magnetic resonance apparatus in high-temperature superconductivity. Conventionally, the cold energy generated by the cryogenic refrigerator is transported to the liquid nitrogen tank of the cooled part to prevent the liquid nitrogen from evaporating, but this cold energy transport method uses high pressure helium gas. Vibration-proof short-distance heat transfer method under common vacuum insulation, in which the cryogenic refrigerator and the cooled part of the liquid nitrogen storage tank are connected with a short heat transfer tube; There was a direct cooling method in which a refrigerator was placed directly.

(Problems to be solved) However, the high-pressure helium gas circulation method has poor cold and heat transport efficiency, making the equipment large and expensive, and there are problems in that high-frequency vibrations caused by pump compression are transmitted to the parts to be cooled. In addition, with the direct cooling method and vibration-isolated short-distance heat transfer method, vibration removal is uncertain, and the operating noise of the refrigerator
There has been a problem in that the cooled section is affected by the generation of an extremely small leakage magnetic field due to the operation of the refrigerator motor.

The present invention has been made with attention to these points, and it is possible to avoid transmitting the vibrations of a refrigerator or the like to the cooled part, and
It is an object of the present invention to provide a cold heat transfer pipe that can transport cold heat with high cold heat transport efficiency.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a refrigerator side joint block that is thermally connected to a cold heat generating part of a cryogenic refrigerator, and a cooled part disposed in the cooled part. It consists of a side joint block, a heat transfer member that connects both blocks, an exterior tube that covers the outer periphery of this heat transfer member, and a heat insulating material filled between the heat transfer member and the exterior tube. It is composed of a copper mesh wire woven from thin copper wires, the outer tube is composed of a flexible material with heat insulation properties, and the heat insulation material is composed of a powdered heat insulation material mixed with a moisture adsorbent.
It is characterized by powder vacuum insulation between the heat transfer member and the exterior tube.

(Function) In the present invention, a refrigerator-side joint block that is thermally connected to the cold heat generation part of the cryogenic refrigerator, a cooled part-side joint block that is arranged in the cooled part, and a heat transfer member that connects both blocks are provided. ,
It consists of an armored tube that covers the outer periphery of the heat transfer member, and a heat insulating material filled between the heat transfer member and the armored tube. It is composed of a composite material of a polymer film and aluminum foil or a flexible material with heat insulating properties such as rubber, the heat insulating material is composed of a powdered heat insulating material mixed with a moisture adsorbent, and the heat transfer member and the outer pipe are used. Since it is formed to provide powder vacuum insulation between the refrigerator and the refrigerator, it is possible to improve the efficiency of cold heat transport from the refrigerator to the cooled parts, and both the heat transfer member and the exterior tube are flexible. Therefore, vibrations on the refrigerator side are not transmitted to the cooled part.

(Embodiment) The drawings show an embodiment of the present invention, in which FIG. 1 is a partially cutaway vertical cross-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 tube connects both blocks: a refrigerator side joint block (1) that is thermally connected to the cold heat generating part of the cryogenic refrigerator, and a cooled part joint block (2) that is placed in the cooled part. It consists 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 made by braiding multiple thin copper wires, and one end of the wire is connected to the refrigerator side joint block (1).
The other end is connected to the heat exchange fin (7) of the joint block (2) on the side of the cooled part. The heat transfer member (3) is bound in the longitudinal direction with binding threads (8) such as glass fiber, nylon thread, Teflon thread, etc. at regular intervals, and is made so as not to come into contact with the inner surface of the outer tube (4). Contact prevention spacer (
9) are attached at regular intervals.

The outer tube (4) is made of a composite material of a polymer film and aluminum foil, or a flexible material having heat insulating and airtight properties such as rubber.

The heat insulating material (5) is composed of a powder heat insulating material such as perlite or Santocel mixed with a moisture adsorbent such as silica gel alumina gel.

This cryotransfer tube is therefore entirely flexible.

Two vacuum and safety valves (10) are provided at the connection between the exterior pipe (4) and the refrigerator side joint block (1), and one vacuum and safety valve (10a) is connected to the exterior pipe (4). It communicates with the gap between the heat transfer member (3), that is, the heat insulating material (5) layer, and the heat insulating material (5) layer is insulated with powder vacuum, and the other vacuum and safety valve ( 10b
) connects the refrigerator side joint block (1) to the cryogenic refrigerator (11
) is connected to the space between the cold heat generating part (12) and the refrigerator side joint block (1), and this space is formed into a vacuum.

Figure 2 shows the case of cooling SQUIRAD's high-temperature superconducting magnetic shielding plate, in which the block (1) on the joint side of the refrigerator side of the low-temperature heat transfer tube is connected to the cold heat generating part (12) of the cryogenic refrigerator (11).
and connect the cooled part side block (2) to the insulating container (13
) is connected to the liquid nitrogen storage tank (14). In Fig. 2, reference numeral (15) is a magnetic shield plate placed in the liquid nitrogen storage tank (14), and (16) is an automatic operation measuring instrument, and this automatic operation measuring instrument (I6) is a liquid nitrogen storage tank ( 1
4) A liquid level gauge (17) that detects the liquid level in the liquid nitrogen storage tank (14), a thermometer (18) that detects the temperature in the liquid nitrogen storage tank (14), and a pressure gauge that detects the pressure in the liquid nitrogen storage tank (14). (19),
Consists of safety valves, etc.

FIG. 3 shows another embodiment, in which a rigid heat transfer member (20) is arranged inside the outer pipe (4), and this rigid heat transfer member (20) and the refrigerator side joint block (1) are connected. It is different from the low-temperature transfer pipe described above in that a heat transfer member (3) made of copper mesh is used to connect the rigid heat transfer member (20) and the cooled part side block (2). The difference from the previous example is that the wire mesh heat transfer member (3) is bound with glass fibers (8), and the contact prevention spacer (9) is attached to the copper wire heat transfer member (3). It is structured similarly. Therefore, in the low-temperature transfer tube of this embodiment, only the portions on both sides sandwiching the rigid heat transfer member (20), that is, the portions connected by the copper mesh heat transfer member (3), are flexible. Note that the portion of the sheathing tube (4) corresponding to the rigid heat transfer member (20) does not need to have flexibility.

In a low-temperature transfer tube configured in this way, the entire transfer tube or at least two parts are flexible, making piping easier. Since the flexible portion absorbs the vibration, the vibration is not transmitted to the cooled portion. In addition, cold heat is transferred to the cooled part using a heat transfer member made of copper mesh, and
The heat transfer members made of copper mesh are tied together with binding thread, spacers are attached at regular intervals to prevent contact, and the tube between the heat transfer member and the outer tube is filled with heat insulating material to create an insulated structure for the low-temperature heat transfer tube. Since the heat transfer member is formed in a curved manner, the heat transfer member does not come into contact with the outer tube, and cold and heat transport efficiency is maintained at a high level.

(Effects) In the present invention, a refrigerator-side joint block that is thermally connected to the cold heat generation part of a cryogenic refrigerator, a cooled part-side joint block that is arranged in a cooled part, and a heat transfer member that connects both blocks. ,
It consists of an armored tube that covers the outer periphery of the heat transfer member, and a heat insulating material filled between the heat transfer member and the armored tube. It is composed of a composite material of polymer film and aluminum foil or a flexible material with heat insulating properties such as rubber, and the heat insulating material is composed of powdered heat insulating material mixed with a moisture adsorbent. Since the space between the parts is formed with powder vacuum insulation, it is possible to improve the efficiency of transporting cold heat from the refrigerator to the parts to be cooled.In addition, both the heat transfer member and the exterior tube are flexible. , vibrations on the refrigerator side can be prevented from being transmitted to the cooled section.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a partially cutaway vertical cross-sectional view of a low-temperature heat transfer tube, FIG. 2 is a schematic configuration diagram showing an example of its use, and FIG. 3 is a first diagram of another embodiment. This is a corresponding diagram. ■・Freezer side joint block, 2・To be cooled part joint block, 3・・Heat transfer member, 4・・Exterior pipe, 5・・Insulating material, 8・・Binding thread, 9・・Contact prevention spacer , 10・
Vacuum pulling/safety valve, 11 Cryogenic refrigerator, 12-Cold heat generation section, 13. Cooled section (insulated container), 20. Rigid heat transfer member.

Claims (4)

[Claims] 1. A heat transfer tube that transports frozen heat generated by a cryogenic refrigerator placed apart from a cooled part to a cooled part, and a refrigerator side joint block that is thermally connected to a cold heat generating part of the cryogenic refrigerator. , a joint block on the side of the cooled part placed in the cooled part, a heat transfer member connecting both blocks, an exterior tube covering the outer periphery of this heat transfer member, and a heat transfer member filled between the heat transfer member and the exterior pipe. The heat transfer member is made of a copper mesh wire woven from thin copper wires, the outer tube is made of a flexible material with heat insulating properties, and the heat insulating material is a powdered heat insulating material mixed with a moisture adsorbent. A low-temperature heat transfer flexible tube characterized in that the heat transfer member and the outer tube are insulated by powder vacuum. 2. According to claim 1, the heat transfer member made of copper mesh wire is bound with 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 exterior tube. low temperature heat transfer flexible tube 3. Claim 1 or 2, wherein a rigid heat transfer member is disposed within the exterior pipe, and the rigid heat transfer member is connected to the refrigerator side joint block and the cooled part side joint block with a copper mesh wire heat transfer member.
Low temperature heat transfer flexible tube described in 4. The low-temperature heat transfer device according to any one of claims 1 to 3, wherein a vacuum and safety valve is arranged between the heat transfer member and the exterior pipe and at the connection portion of the refrigerator side joint block to the refrigerator output part. flexible tube