JPS6161553B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention allows gas such as helium generated in the inner tank to be removed from the cryogenic inner tank containing liquid helium superconducting coils, etc., through the room temperature outer tank provided for vacuum insulation. This invention relates to a cryostat that insulates and supports piping leading to the outside or injecting liquid into an inner tank.

Figure 1 is a sectional view of the cryostat.

In the figure, 1 is a superconducting coil, 2 is liquid helium that cools the superconducting coil 1, 3 is a first container that stores the superconducting coil 1 and liquid helium 2, and 4 is a vacuum insulated first container 3 from outside temperature. The interior of the second container is kept in a vacuum state. Reference numeral 5 denotes a lead-out pipe for leading helium gas generated in the first container 3 to the outside or injecting liquid; 6 a support device for supporting the lead-out pipe 5 in a heat-insulating manner; Reference numeral 7 denotes an inner tank support member that supports the first container 3 in a suspended manner. In order to maintain the superconducting coil 1 in a superconducting state, it is necessary to maintain the superconducting coil 1 at an extremely low temperature of liquid helium. However, since liquid helium evaporates due to heat entering from the outside, reducing the amount of heat entering leads to extending the operation time of the superconducting coil 1 in the superconducting state and saving helium. Heat intrusion can be roughly divided into two types: heat conduction from the outlet pipe 5, inner tank support material 7, etc. that are directly connected from the first container 3 to the second container 4, and radiant heat to the surface of the first container 3. However, the proportion of heat intrusion due to heat conduction is large, especially reducing the heat intrusion from the outlet pipe 5 greatly contributes to improving the function of the cryostat. To reduce heat conduction from the outlet pipe 5, it is possible to lengthen the pipe length or reduce the pipe diameter, but since the pipe diameter is determined by the amount of liquid injected per hour, the amount of gas discharged, and the pressure loss of the pipe,
Generally, the tube length is increased within the range allowed by the structure of the cryostat.

However, the elongated outlet pipe 5 is connected to the first container 3 and the second container.
If the container 4 is supported at two points, stress will be concentrated on the support portion due to vibration. Further, since the natural frequency is often lowered and disadvantageous due to resonance, etc., a heat insulating support device 6 for the outlet pipe 5 is provided in both containers 3 and 4 from the viewpoint of mechanical strength.

Conventionally, this type of support device is shown in Figures 2 and 3.
I found what is shown in the figure. In the figure, 8 is a fixing base fixed to the second container 4, 9 is a multilayer laminated heat insulating material such as CSI wrapped around the outlet pipe 5, 10 is a band for fixing the heat insulating material, and 11 is a band 10. and a fixed base 8 with bolts 12 and 13.

With the above configuration, external heat is conducted from the second container 4 to the fixing base 8 to the support column 11 to the band 12, but the heat insulating material 9 is designed to insulate heat from entering the outlet pipe 5. However, in this structure, when liquid helium is stored in the first container 3, the outlet pipe 5 undergoes thermal contraction with a temperature difference of about 300°C from room temperature,
When the temperature of the container 3 is raised, on the contrary, thermal expansion occurs when viewed from a low temperature, so the outlet tube 5 moves relative to the support device 6 due to this thermal contraction or expansion. It is sufficient if the heat insulating material 9 follows the movement of the lead-out pipe, but due to the frictional force between the lead-out pipe 5 and the heat insulating material 9, the heat insulating material 9 tends to collapse as shown in FIG. In the past, it had the disadvantage of increasing the rate of collapse.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and by reducing the frictional force between the supporting part and the lead-out pipe to facilitate the movement of the lead-out pipe due to thermal contraction or expansion, the present invention provides a lead-out that is resistant to vibration. A cryostat having a tube support device is provided.

The figures will be explained below. In FIGS. 5 and 6, numbers 4 to 6, 8, and 10 to 13 are the same as in the prior art. Reference numeral 14 denotes a multi-layered heat insulating material such as CSI wrapped around the circumference of the outlet pipe 5, and has a collar 14a.
Reference numeral 15 denotes a sliding material which is interposed between the heat insulating material 14 and the lead-out pipe 5 and has a structure in which it is able to insulate the lead-out pipe 5 and to slide against thermal deformation of the pipe. Chrysanthemum-shaped groove 15 provided in the axial direction of 5
It has a. The sliding material 15 is made of an organic material with good sliding properties and low thermal conductivity, such as Teflon or nylon. Note that 10 to 15 constitute a support device 6. This improves the heat insulation effect, and since the chrysanthemum-shaped groove 15a is provided in the axial direction of the outlet tube 5 at the contact part with the outlet tube 5, sliding friction is reduced and movement due to thermal deformation of the outlet tube is reduced. becomes easier. Furthermore, by providing the flange 14a on the heat insulating material 14, it is possible to restrain the insulating material 14 from collapsing in the axial direction of the outlet pipe 5, thereby preventing it from collapsing due to vibration. Furthermore, if the surface of the outlet pipe 5 that comes into contact with the sliding material 15 is polished to reduce the sliding friction with the heat insulating material, the effect will be extremely large.

According to this invention, the insulation material is prevented from collapsing due to thermal contraction or expansion of the outlet pipe, and the supporting device is strong against mechanical strength such as vibration.

Furthermore, a heat insulating material is placed between the heat insulating material and the outlet tube to enhance the heat insulation effect, which reduces heat conduction from the outside, reduces the amount of evaporation of liquid helium, and extends the operating time of the superconducting coil. can.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the cryostat, Figure 2 is a perspective view showing the main parts of the conventional cryostat, and Figure 3 is the same as in Figure 2.
4 is an explanatory diagram showing the collapse of the insulation material, FIG. 5 is a perspective view showing the main part of the present invention, and FIG.
The figure is a sectional view taken along the - line in FIG. 5. In the figure, 1 is a superconducting coil, 3 is a first container, 4 is a second container, 5 is an outlet pipe, 6 is a support device, 14 is a heat insulating material, and 15 is a sliding material. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A first container containing a superconducting coil and filled with liquid helium is surrounded by a second container and vacuum insulated, and the second container is penetrated and connected to the first container. The device has a connected lead-out pipe and a support device for fixing the lead-out pipe to the second container within the second container, wherein the support device includes a layered heat insulating material surrounding the lead-out pipe. and a sliding material which is interposed between the heat insulating material and the outlet pipe and is made of an organic material and has a better sliding property with respect to the outlet pipe than the heat insulating material, and which is fixed to the second container. A cryostat comprising the above-mentioned heat insulating material and a fixing member that supports the outlet pipe via the sliding material. 2. The cryostat according to claim 1, wherein the heat insulating material is CSI. 3. The cryostat according to claim 1 or 2, wherein the sliding material is Teflon or nylon. 4. Claim 1 or 2, characterized in that the sliding material has a plurality of grooves in the axial direction of the outlet pipe.
Cryostat described in section. 5. Claims 1 to 5 are characterized in that the outlet pipe has a mirror finish at the contact portion with the sliding material.
The cryostat according to any of paragraph 4.