JPH04269807A - Heat insulating supporting body - Google Patents

Abstract

PURPOSE:To obtain an insulating supporting body which is optimum for cryogenic containers by providing a folded metallic hardware which couples a fiber- reinforced plastic cylinder with a fiber-reinforced plastic rod reducing the reaction caused by low-temperature contraction by lowering the rigidity of the folded metallic hardware in the direction perpendicular to the load supporting direction. CONSTITUTION:A cylinder 2 and a rod 4 are coupled with each other by means of a folded metallic hardware 3 and flanges 1 and 5 are respectively fitted to one ends of the cylinder 2 and the rod 4. The cylinder 2 and the rod 4 are formed of a fiber-reinforced plastic(FRP) material so as to insulate heat by the cylinder 2 and the rod 4. The fiber used for the fiber-reinforced plastic material is glass fibers, carbon fibers, or alumina fibers. The flanges 1 and 5 are respectively fitted to a normal-temperature section and low-temperature section so as to support loads applied in the axial direction.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating support for supporting a cryogenic container for storing liquid helium, liquid hydrogen, liquid nitrogen and other liquefied gases from a room temperature region.

0002

2. Description of the Related Art A cryogenic container for storing liquefied gas or the like is usually housed in a vacuum chamber for heat insulation. Then, it is supported from the normal temperature part in a vacuum by a heat insulating support that supports its own weight or a load such as an earthquake load.

A typical example of this heat insulating support is
No. 4-97735. In this example, the compressive load is supported by two cylinders and a folding device connecting them. In this way, using a folding tool to make the inner cylinder fit into the outer cylinder is as follows:
This is to shorten the axial length of the heat insulating support, thereby preventing the vacuum chamber from becoming larger than necessary.

0004

An explanatory diagram of a cryogenic container using a conventional heat insulating support is shown in FIG.

As shown in this figure, a plurality of heat-insulating supports are normally used, and in order to minimize the number of heat-insulating supports and support them efficiently, the support interval 1 is usually set large.

[0006] The problem here is thermal shrinkage of the cryogenic container.

[0007] As is generally known, all materials shrink when cooled. Therefore, the support distance 1 of the cryocontainer also contracts. Therefore, the heat insulating support is forcibly deformed in a direction perpendicular to the load supporting direction. The amount of deformation increases as 1 increases. As a result, there are cases where the heat insulating support is damaged due to the large stress generated in the heat insulating support. Moreover, the need to take this into account is a major constraint on the design of cryogenic containers.

[0008] In order to solve this problem, the present invention provides a heat insulating support that has low rigidity (spring constant) in the direction perpendicular to the load supporting direction and that reduces reaction force due to forced deformation.

[0009] In addition, efforts have been made to prevent the mechanical strength from decreasing as the rigidity is lowered.

0010

SUMMARY OF THE INVENTION The gist of the invention is the use of solid rods for insulation.

[0011] This specific action and the details of the structure that does not impair mechanical strength will be explained below.

0012

[Operation] The principle of the present invention is shown in FIG.

[0013] Letting the outer diameter of the rod at the center be D and the length L, the amount of displacement x when receiving force F in the direction perpendicular to the axis of the rod is x=FL3/(12EI) where E: Longitudinal elastic modulus I: Expressed by the moment of inertia of area.

Therefore, the reaction force F when subjected to forced displacement x
becomes F=12EIx/L3.

[0015] Also, the strength of this rod in the axial direction is Fa=S
aA where Sa: allowable stress A: cross-sectional area From this result, taking the ratio of strength Fa and reaction force F, we get F
a/F=SaA/(12EI/L3)∝A/I.

Assuming that this rod is a cylinder with an outer diameter D and an inner diameter d, I=π/64・(D4−d4) A=π/4・(D2−d2) ∴A/I=1/{ 16(D2+d2)}. That is,
It can be seen that the shape with the highest strength and the lowest reaction force against forced displacement is d=0, that is, a solid rod.

On the other hand, at the joint between the rod and the metal fitting, the adhesive area between the outer periphery of the rod and the metal fitting is S=πDa, but if this is a cylinder with an outer diameter D and an inner diameter d, then S=π(
D+d)a, so the rod is disadvantageous in terms of adhesion. In order to compensate for this, it is important to make the insertion length a sufficiently large if the adhesive strength is to be used to provide strength.

[0018]

[Examples] Examples of the present invention will be described below.

FIG. 3 shows a basic explanatory diagram of the present invention.

The cylinder 2 and the rod 4 are connected via a folding tool 3. Then, a flange 1 is attached to one end of the cylinder 2, and a rod 4
A flange 5 is attached to one end of each.

[0021] The flanges 1 and 5 are connected to a vacuum chamber and a low temperature container using bolt holes.

Fiber-reinforced plastic (hereinafter referred to as FRP) is used for the cylinder 2 and the rod 4, and these parts are insulated. Glass is generally used as the reinforcing fiber for FRP, but high strength can be obtained by using carbon fiber or alumina fiber. FRP may be used for the folding tool 3, but it is preferably made of metal so as not to reduce the strength.

The cylinder 2 and the rod 4 are connected to the metal fittings by adhesion, and it is particularly important to increase the insertion length of the adhesive portion of the rod 4 in order to increase the adhesive area. In the example in this figure, it is three times the outside diameter of the rod.

The configuration of FIG. 3 can also handle not only compressive loads but also tensile loads.

FIG. 4 shows another embodiment of the present invention.

[0026] Instead of the flange 5, a mounting fitting 6 having a thread on the outer diameter is attached. In this way, it can be mounted directly by screwing in without using bolts, which is convenient when there is no mounting space.

The same can be said of the flange 1.

FIG. 5 shows another embodiment.

Regarding the connecting portion between the rod 4 and the metal fitting 6, the FRP insertion hole of the metal fitting 6 is made tapered, and the space between the rod 4 and the metal fitting 6 is filled with resin 7. Further, a screw is provided at the bottom of the hole, and a push screw 8 is used to press the rod 4.

Generally, the adhesive force between FRP and resin is greater than that between metal and FRP or metal and resin, so if this is done, the rod 4 and the metal fitting 6 can be connected even if there is no adhesive force between the metal fitting 6 and the resin 7. is strongly maintained.

The same can be said of the folding tool 3.

FIG. 6 shows another embodiment.

[0033] The tapered hole portion is screwed, and a screw 9 is provided on the outer diameter of the rod 4 and screwed into the metal fitting 6. This also provides a strong bond. The push screw 8 is necessary to prevent the screw from rotating.

FIG. 7 shows another embodiment.

[0035] Metal fittings 12 and 13 are attached to both ends of the FRP rod 4, and are rotatably connected to the folding tool 3 and the low temperature container using pins 10 and 11, respectively.

[0036] In this way, the reaction force in the direction perpendicular to the axis can be completely reduced to zero, so it is suitable when the mounting interval of the heat insulating supports is large and the amount of shrinkage is large.

[0037] This pin support portion may be replaced with a ball joint. In that case, the degree of freedom is further increased, and reaction force against rotation around the axis can be eliminated.

[0038]

[Effects of the Invention] According to the present invention, the rigidity in the direction perpendicular to the axial direction can be lowered without reducing the strength of the joint, so the reaction force due to low-temperature shrinkage can be reduced, making it ideal for cryogenic containers. It is possible to obtain a heat insulating support.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the principle of the present invention.

FIG. 2 is an explanatory diagram showing the usage status of the present invention.

FIG. 3 is a sectional view showing a second embodiment of the invention.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

FIG. 5 is a sectional view showing a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a fifth embodiment of the present invention.

FIG. 7 is a sectional view showing a sixth embodiment of the present invention.

[Explanation of symbols]

1, 5...flange, 2...ERP cylinder, 3...folding tool, 4
...FRP rod, 6...Mounting bracket, 7...Resin, 8...Press screw, 9
...screw, 10,11...pin, 12,13...metal fitting.

Claims (7)

[Claims] 1. A heat insulating support comprising a cylinder made of fiber-reinforced plastic and a folding tool made of metal that connects the rod made of fiber-reinforced plastic. 2. The heat insulating support according to claim 1, wherein the reinforcing fibers are glass fibers, carbon fibers, or alumina fibers. 3. The heat insulating support according to claim 1, wherein a metal flange for attachment to another structure is attached to one end of the fiber-reinforced plastic cylinder and one end of the rod. 4. The heat insulating support according to claim 3, wherein one or both of the flanges are replaced with screws and are directly attached by screwing. 5. The heat insulating support according to claim 3, wherein the fiber-reinforced plastic rod and the metal fitting are connected by screws. 6. The heat insulating support according to claim 3, wherein the fiber-reinforced plastic rod and the metal fitting are connected by a tapered hole and a set screw. 7. The heat insulating support according to claim 5 or 6, wherein a pin support or a ball joint is provided at one or both ends of the fiber-reinforced plastic so that it can rotate freely.