JPH0416059Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to the structure of a cryogenic container that insulates and holds a cryogenic refrigerant.

[Conventional technology]

Conventionally, containers of this type include, for example:
CRYOGENIC CONSULTANTS LIMITED (UK) GLASSFIBRE HELIUM
CRYOSTAT: There is one shown in the Buket Cryostat catalog. Figure 4 shows its schematic structure. In the figure, reference numeral 1 denotes an inner tank having an opening in which the cryogenic cryogen 6 is stored. It flows into the cryogenic part side. 2 is an outer tank arranged around the outer circumferential side of the inner tank 1;
3 is a lid that covers the opening of the inner tank 1, 4 is an injection pipe for the cryogenic cryogen 6, and 5 is an exhaust pipe for the evaporated cryogenic cryogen 6. Although not shown, there is a vacuum space between the inner tank 1 and the outer tank 2, and depending on the model, a radiant heat shield may be provided. Further, a baffle plate (not shown) may be provided in the space between the lid 3 and the cryogenic cryogen 6 to reduce heat inflow from the lid 3 due to radiation and heat inflow due to convection.

Next, the operation will be explained. The inner tank 1 and the outer tank 2 are combined to form a kind of thermos bottle, and the space between them is vacuum insulated. The cryogenic cryogen 6 housed inside the inner tank 1 is taken in and out of the normal temperature space through an injection pipe 4 and an exhaust pipe 5. Inner tank 1
not only houses the cryogenic cryogen 6, but also supports its weight and functions as a pressure vessel that can withstand the pressure difference between the inside and outside. Since the inner tank 1 is a heat conductor from room temperature to extremely low temperature, its design aims to reduce the heat transfer area and increase the heat transfer distance, but as mentioned above, the cryogenic cryogen 6 It is impossible to obtain sufficient thermal insulation performance due to the mechanical constraints of being a pressure vessel and supporting the weight of .

[Problem that the invention attempts to solve]

In the case of the inner tank 1 of the conventional cryogenic container, the strength, which is a mechanical constraint, is considered simply by considering the material strength at room temperature, and the cylindrical part is constructed with the same thickness obtained up to the cryogenic side. . Therefore, the amount of heat flowing from the normal temperature section to the cryogenic section through the inner tank 1 becomes unnecessarily large, which impairs the heat insulation retention performance of the cryogen 6 contained therein.

This idea was made to solve the problems mentioned above, and it was developed to create a cryogenic container that can improve insulation retention performance by reducing the flow of heat from the normal temperature part of the inner tank to the cryogenic part. The purpose is to obtain.

[Means for solving problems]

In the cryogenic container according to this invention, the wall thickness of the inner tank is
The wall thickness is large on the room temperature side and the wall thickness is small on the cryogenic temperature side.

[Effect]

By reducing the heat transfer area of the inner tank in this invention without impairing its strength, the flow of heat from the normal temperature part to the cryogenic part due to heat conduction in the inner tank is reduced.

[Example of idea]

An embodiment of this invention will be described below with reference to the drawings. In FIG. 1, numerals 2, 3, 4, 5, and 6 are the same as the conventional ones described above. 7 is an inner tank with a large wall thickness on the room temperature side and a small wall thickness on the cryogenic side. In the figure, as an example, the wall thickness of the inner tank is changed from the normal temperature side to the cryogenic side. The figure shows the case where the temperature is gradually decreased. That is, it is configured in a tapered shape.

Next, the operation will be explained. Outer tank 2, lid 3,
The injection pipe 4 and the exhaust pipe 5 are the same as those of the conventional ones. Since the inner tank 7 is in contact with room temperature and cryogenic temperature, a temperature distribution occurs in the longitudinal (axial) direction.
Additionally, structural materials generally have the property that their strength increases as the temperature decreases. Using the properties of this material, we calculate the strength of each tiny length in the longitudinal direction according to the temperature and find the cross-sectional area necessary for strength. The cross-sectional area becomes smaller, and the average heat transfer area becomes smaller than that of the inner tank 7 designed in the prior art, so that the heat inflow flowing through the inner tank 7 can be reduced.

In the above embodiment, the strength of the inner tank 7 was calculated for each minute length, but as shown in FIG. You can also design by doing this. That is, it may be configured in a stepwise manner.

Further, in the above embodiment, a case was explained in which the container holds only the cryogenic cryogen 6 insulated, but the superconducting coil 8 using liquid helium as the cryogenic cryogen 6 is housed in the inner tank 7, and the current lead 9 is connected to the lid. 3
The container may be a cryogenic container taken out from the container, and the same effect as in the above embodiment can be obtained.

[Effect of idea]

As described above, according to this invention, the wall thickness of the inner tank is configured such that the wall thickness on the room temperature side is large and the wall thickness on the cryogenic side is small, so the average heat transfer area of the inner tank can be reduced. The amount of heat that flows through the tank can be reduced, and the amount of heat that flows into the container as a whole is also reduced accordingly, resulting in an effect that the heat insulation retention performance can be improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a cryogenic container according to one embodiment of this invention, Fig. 2 is a sectional view showing a cryogenic container according to another embodiment of this invention, and Fig. 3 is a sectional view showing a cryogenic container according to another embodiment of this invention. FIG. 4 is a cross-sectional view of a conventional cryogenic container. In the figure, 2 is an outer tank, 6 is a cryogenic cryogen, and 7 is an inner tank. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] There is an inner tank with an opening in which the cryogen is stored, and the heat from the room temperature side of the opening flows into the cryogenic part of the storage part for the cryogen. In a cryogenic container for insulating and storing a cryogenic cryogen, the inner tank is composed of an outer tank surrounding the tank and has a larger wall thickness on the room temperature side and a smaller wall thickness on the cryogenic side. A cryogenic container characterized by: