JPH0243959B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a cryogenic apparatus, and particularly to a cryogenic apparatus suitable for storing or transferring cryogenic fluid.

[Background of the invention]

Cryogenic equipment for storing or transferring cryogenic fluids such as liquid helium, for example, cryogenic fluid transfer piping for transferring cryogenic fluids, for example,
As described in Publication No. 131885, an inner tube through which a cryogenic fluid flows; a heat shield tube disposed outside the inner tube to form a vacuum insulation space with the outer surface of the inner tube;
The cooling tube is fixed to the outside of the heat shield tube by silver brazing, etc., and the outer tube is installed outside the heat shield tube to form a vacuum insulation space with the outer surface of the heat shield tube. Are known.

In contrast to such conventional techniques, the inventor of the present invention proposed a patent application filed in 1983 to improve the transfer efficiency of low-temperature fluid by increasing the heat absorption effect of the intruding heat by the heat shield tube. - There is No. 157521. This is achieved by providing a double layer of heat shield tubes to create a heat conduction medium atmosphere inside, passing a cooling tube through the heat conduction medium atmosphere, and efficiently cooling the heat shield tubes via the heat conduction medium. We are trying to increase the heat absorbing effect of the intruding heat.

However, for such a structure, for example, the 9th International Conference on Cryogenics held in Kobe from May 11th to 14th, 1982 (POCEEDINGS)
OF THE Ninth International Cryogenic
Engineering Conference, KOBE, JAPAN,
11-14 MAY 1982), pp. 100 to 103, especially when the cooling pipe (LN ₂ ) for radiation shielding is structured to reciprocate as shown in Figure 2,
In other words, there is an inner tube that is an internal material that transfers the cryogenic fluid inside, a heat shield tube that is a heat shield member that covers the outer surface of the inner tube, and a heat shield tube that is a material between the temperature of the cryogenic fluid and the atmospheric temperature. Refrigerant, cooling to temperature
For example, a cooling pipe that is a cooling member that contains liquid nitrogen inside, a return pipe that is a return member that contains a return fluid from an object to be cooled, such as a refrigerant that is returned after cooling a heat shield member, and an inner pipe. and an outer tube which is an external material containing a heat shield tube, a cooling tube, and a return tube inside, and a space formed by the inner tube and the heat shield tube as well as a space formed by the heat shield tube and the outer tube. When the space is evacuated, the temperature of the return refrigerant from the object to be cooled (heat shield member) inside the return pipe is higher than the temperature of the refrigerant inside the cooling pipe, and the heat shield member is There is a problem with sufficient cooling, and the heat absorption effect by the heat shield member is not sufficiently obtained, resulting in a reduction in the transfer efficiency of the cryogenic fluid.

Note that the reason why the return pipe is passed through the heat conduction medium atmosphere formed in the heat shield member is to make the transfer pipe compact by effectively using the space within the low temperature fluid transfer pipe.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-temperature device in which a cooling tube for a heat shield is reciprocated within the low-temperature device, and a decrease in storage efficiency or transfer efficiency of cryogenic fluid can be prevented.

[Summary of the invention]

The present invention forms an airtight chamber in which gas is sealed inside a heat shield member that covers the outer surface of an internal member that stores or transfers cryogenic fluid therein, and separates the heat shield member between the temperature of the cryogenic fluid and the atmospheric temperature. A cooling member having a refrigerant therein to cool the object to a temperature between By insulating the return member with the heat shield member, the heat shield member is sufficiently cooled by the refrigerant inside the cooling member.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. 1 to 3 show a case in which the present invention is applied to a low-temperature device, for example, a low-temperature fluid transfer pipe.

In FIGS. 1 and 2, an inner tube 10 is an internal member for transporting a cryogenic fluid, for example, liquid helium.
A nozzle 11 is welded to the inner end of the nozzle 1.
1 is hermetically welded to an end plate 13 of an outer tube 12, which is an outer member. The heat shield tube 14, which is a heat shield member that covers the outer surface of the internal member, is composed of a tube 15, another tube 16, and an end plate 17. The tube 15 is arranged concentrically outside the inner tube 10 and the other tube 16 is arranged concentrically outside the tube 15. tube 15
End plates 17 are airtightly provided at both ends of the other tube 16, and an airtight space 18 is formed by the tube 15, the other tube 16, and the end plate 17. A cooling tube 19 that is a cooling member that has a refrigerant inside that cools the heat shield tube 14 to a temperature between the temperature of liquid helium and the atmospheric temperature.
A return pipe 20, which is a return member containing helium gas therein, passes through the airtight space 18 from the object to be cooled (for example, a heat shield material) to the helium liquefaction device. It is provided. The outer surface of the return pipe 20 is provided with a heat insulator 21 made of a polymeric material such as silicone rubber, for example. Helium gas is sealed between the airtight chambers 18 as a gas having good thermal conductivity. Cooling pipe 19
The return pipe 20 and the return pipe 20 are taken out to the outside through nozzles 22 and 23 that are airtightly provided in the outer pipe 12, respectively. The inner tube 10 and the tube 15 of the heat shield tube 14, the other tube 16 of the heat shield tube 14 and the outer tube 12
This support is provided by spacers 24 and 25. A heat insulating space 26 including the inner tube 10 of the outer tube 12 and the heat shield tube 14 is evacuated.

The cryogenic fluid transfer piping constructed in this manner is applied, for example, by being installed between a cryostat and a helium liquefaction device, as shown in FIG. Inside the cryostat 27, a liquid helium tank 29 containing a built-in magnet and a heat shield plate 28 provided surrounding the liquid helium tank 29 are arranged.
The inside of the cryostat 27 is vacuum insulated.
The helium liquefaction device includes a refrigerator 31 which has a liquefaction means consisting of a plurality of heat exchangers and cold generating means in a vacuum-insulated container, and supplies helium gas to the refrigerator 31 through a high pressure line 32 and a low pressure line 33. It is composed of a compressor 30 that supplies and circulates. The cryogenic fluid transfer piping has one end of the outer pipe 12 connected to the refrigerator 31 and the other end connected to the cryostat 27, respectively. One end of the inner tube 10 is connected to a liquefied helium container of a refrigerator 31, and the other end is connected to a liquid helium tank 29 of a cryostat 27. One of the cooling pipes 19 is branched off from the high pressure line 32 of the refrigerator 31, and the other is wrapped around the shield plate 28 of the cryostat 27. One of the return pipes 20 is connected to the cooling pipe 19 wrapped around the shield plate 28, and the other is connected to a low pressure line 33 of the refrigerator 31 at a point at a temperature higher than the branch point of the cooling pipe 19. The gas from the liquid helium tank 29 is stored in the gas holder 34, and is supplied to the helium liquefaction device as needed.

In the cryogenic fluid transfer piping configured in this way,
For example, helium gas at a temperature of 65 K from the refrigerator 31 is passed as a refrigerant through the cooling pipe 19. In the return pipe 20, helium gas whose temperature has been raised to, for example, 85K flows through the return pipe 20 to cool the shield pipe 14 and the shield plate 28, which are objects to be cooled. The tube 15 of the heat shield tube 14 and the other tubes 16 are
By cooling the helium gas in the cooling pipe 19, the temperature of the helium gas in the airtight space 18 increases as a heat transfer medium.
It is sufficiently cooled to about 67K. In addition, the airtight space 1 is sealed by helium gas at a temperature of 85K by the heat insulator 21.
8, that is, the temperature of the heat shield tube 14, is prevented from rising. If there were no heat insulator 21, the temperature of the heat shield tube 14 would rise to 76K, which would cause the heat shield tube 14 to rise to the inner tube 10.
The heat transfer by radiant heat will increase by 56%.

In this embodiment, the following effects can be obtained.

(1) Since the heat shield tube can be sufficiently cooled by the refrigerant in the cooling tube without being affected by the humidity in the return tube, it is possible to prevent a drop in the transfer efficiency of liquid helium due to the low-temperature transfer tube.

(2) Just pass it through the space inside the shield tube 14,
Since the work of arranging the cooling pipe and the return pipe can be simplified, the manufacturing cost of the low temperature transfer pipe can be reduced.

In this embodiment, a cryogenic transfer pipe is used as an example of the cryogenic device, but the present invention can also be similarly applied to a cryogenic storage tank that stores cryogenic fluid therein.

〔Effect of the invention〕

According to the present invention, in a device that reciprocates a cooling pipe for a heat shield in a low-temperature device, even if a return pipe is provided, a decrease in storage efficiency or transfer efficiency of cryogenic fluid can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a cryogenic transfer tube showing an embodiment of the cryogenic apparatus according to the present invention, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, and FIG. It is a figure which shows the flow of a cooling device which showed the example of attachment of a transfer pipe. DESCRIPTION OF SYMBOLS 10... Inner pipe, 12... Outer pipe, 14... Heat shield tube, 18... Airtight space, 19... Cooling pipe, 20... Return pipe, 21... Heat insulator.

Claims (1)

[Claims] 1. An internal member that stores or transfers a cryogenic fluid therein, a heat shield member that covers the outer surface of the internal member, and a refrigerant that cools the heat shield member to a temperature between the temperature of the cryogenic fluid and atmospheric temperature. a cooling member having a cooling member therein, a return member having a return fluid from an object to be cooled therein, and an outer member including the inner member, a heat shield member, a cooling member, and a return member therein. In the above, an airtight space in which gas is sealed is formed inside the heat shield member, the cooling member and the return member are provided through the airtight space, and a heat insulator is provided on the outer surface of the return member. Characteristic cryogenic equipment.