JPH0821732B2 - Cryogenic container manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a cryogenic container used for housing a superconducting coil by immersing it in liquid helium.

(Prior Art) FIG. 5 shows a state in which a superconducting coil used in a superconducting device is housed in a cryogenic container. Ie center line (C)
Since the superconducting coil (1) provided around is operated below the critical temperature, it is immersed in a cryogen such as liquid helium (2), and these superconducting coil (1) and liquid helium (2) are , Cylindrical helium vessels (3)
It is stored inside. Helium container (3) is coil (1)
The outside is covered with a helium container outer cylinder (3a), the inside is covered with a helium container inner cylinder (3b), and the end is covered with a helium container end plate (3c). Outside the helium container (3),
The radiation shield (4) covered with a radiation shield (4) kept at a cryogenic temperature of about 80 K with liquid nitrogen or a refrigerator is an outer cylinder (4a) and an inner cylinder (4b) of the radiation shield.
And the end plate (4c). Further, a vacuum container (5) that integrally houses the radiation shield (4) and the helium container (3) is provided. Like the radiation shield (4), the vacuum container (5) is also composed of an outer cylinder (5a), an inner cylinder (5b) and an end plate portion (5c) of the vacuum container.

In such a cryogenic container, a high vacuum is maintained between the helium container (3) and the vacuum container (5) so that a high vacuum heat insulating layer can be formed and the helium container (3) and the vacuum container (5). ) Shall be airtight and shall be sufficiently exhausted.

In addition, combining this high-vacuum heat-insulating layer with a multi-layer heat-insulating layer made of aluminum foil as a metal foil (hereinafter referred to as “super insulation”) has excellent heat insulation properties and consumes less liquid helium. It has features such as reduction.

(Problems to be solved by the invention) Super insulation is applied to a helium container (3).
And the radiation shield (4) and the radiation shield (4)
The first conventional means for attaching between the vacuum container (5) and the vacuum container (5) is to stack aluminum foil (6) on the wall of the container so as not to come off with bolts made of a material having excellent heat insulation. Install to form super insulation. Second
As a means of this, as in Japanese Utility Model Publication No. 53-5495, aluminum foil is laminated, and a plurality of thin threads made of a heat insulating material are sewn at multiple points to form a super insulation unit, and each unit is attached to a container. However, the first means has the drawback that even if the bolts are excellent in heat insulation, the amount of heat that conducts the bolts is large and it is difficult to mount the bolts. Since there is a gap in the joints such as the end plate portion and the like, there is a drawback that the thermal insulation of that portion is extremely deteriorated.

In addition, these super insulation forming methods also have a drawback that the work of stacking and mounting is very troublesome.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a cryogenic container having a super insulation, which has a good heat insulating effect and is easy to manufacture.

[Structure of Invention]

(Means for Solving the Problems) In order to achieve the above object, in the present invention, n + 1 concentric hollow cylinders are provided, where n is a positive integer, and end plate portions are provided at both ends of each cylinder. In a method for manufacturing a cryogenic container in which n superinsulations made of metal foils of a plurality of layers are arranged between a plurality of cylindrical containers, an end plate portion of the innermost container is the innermost container. It is attached to the outer cylinder and the inner cylinder, and metal foils longer than the cylinder length are wrapped around the outer cylinder of the n-th container from the inside and the inner cylinder of the (n + 1) th container, respectively, and the shaft protruding from the cylinder is almost axial. Direction incision is made, and the end is alternately or outwardly folded to the outside of the end plate of the nth container to form super insulation, and then n +
Attach the first end plate to the (n + 1) th hollow cylinder.

(Operation) According to the above method, it is possible to manufacture a cryogenic container provided with super insulation that is easy to work and does not have a risk of deteriorating the thermal insulation of the joint.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to Figs.
It will be described with reference to the drawings. The finished cryogenic container is similar to that shown in FIG. 5 except that the super-insulation portion (in this case, an aluminum foil) shown in FIG. 5 has a superposed portion as shown in FIG. See this as well.

First, a combination of the outer cylinder (3a), the inner cylinder (3b) and the end plate portion (3c) of the innermost helium container (3) is completed.

A method of forming super-insulation of an aluminum foil (6), which is a metal foil, between the helium container (3) and the radiation shield (4) in the case of n = 1 where n is a positive integer will be described below. . The method of forming super insulation between the radiation shield (4) and the vacuum container (5) is similar to these.

First, as shown in FIGS. 1 and 2, an aluminum foil (6) wider than these is gently wrapped around each of the outer cylinder (3a) of the helium container and the inner cylinder (4b) of the radiation shield.

Then, as shown in FIG. 3, the helium container (3) and the radiation shield inner cylinder (4b) are combined, and as shown in FIG. 4, the helium container outer cylinder (3a) and the radiation shield inner cylinder (4b) are combined.
Around the both sides of the aluminum foil (6) wound around the both sides, substantially axial cuts are made in the bulged portions, and the helium container end plate portion (3c) is bent and laminated alternately or every several sheets.

With this, it was possible to cover the entire surface of the helium container with super insulation without creating a gap at the joint. Attach the radiation shield outer cylinder (4a) and end plate (4c) to this.

According to this embodiment, the super-insulation can be constructed by winding the aluminum foil (6) around the cylindrical body, which is very easy in manufacturing, and the end plate portion can be covered without forming a gap at the joint. As it can be done, it has a very good thermal insulation performance.

Other Embodiments In the above embodiment, since the radiation shield between the vacuum container and the helium container is single, the super-insulation has a two-stage configuration, but the temperature of the cryogen for cooling the shield and the freezing In consideration of machine performance and the like, when n is 2 or more and a plurality of shields are provided, a cryogenic container can be configured. In this case, the number of superinsulations is “the number of radiation shields (n) +1”.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a cryogenic container having super insulation, which is easy to manufacture, hassle-free, and has excellent heat insulation performance.

[Brief description of drawings]

1 to 4 are longitudinal sectional views showing the state of a cryogenic container manufactured according to the order of the method of one embodiment of the present invention,
FIG. 5 is an upper half longitudinal sectional view showing an ideal configuration of a cryogenic container common to the conventional and the present invention. 3 ... a helium container that is one of the cylindrical containers, 3a ... an outer cylinder of the helium container, 3b ... an inner cylinder of the helium container, 3c ... an end plate of the helium container, 4 ... one of the cylindrical containers Radiation shield, 4a ... radiation shield outer cylinder, 4b ... radiation shield inner cylinder, 4c ... radiation shield end plate, 5 ... vacuum container, which is one of the cylindrical containers, 5a ... … Vacuum container outer cylinder, 5b …… Vacuum container inner cylinder, 5c …… Vacuum container end plate, 6 …… Super insulation aluminum foil.

Claims (1)

[Claims] 1. An n-piece comprising n + 1 concentric hollow cylinders, where n is a positive integer, and consisting of a plurality of layers of metal foil between a plurality of cylindrical containers provided with end plate portions at both ends of each cylinder. In the method for manufacturing a cryogenic container having the above-mentioned super insulation, the end plate portion of the innermost container is attached to the outer cylinder and the inner cylinder of the innermost container, and the nth container from the inside is attached. Outer casing and n
Wrap a metal foil longer than the cylinder length around the outer circumference of the inner cylinder of the + 1st container, make a notch in the axial direction at the part protruding from the cylinder, and alternate the ends on the outside of the end plate of the nth container. Alternatively, a method for producing a cryogenic container is characterized in that every several sheets are folded to form super insulation, and then the (n + 1) th end plate portion is attached to the (n + 1) th hollow cylinder.