JP2673012B2 - Cold box - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cold box that accommodates equipment used at extremely low temperatures in a state of being thermally insulated from the outside.

[Conventional technology]

Generally, this type of cold box includes, as shown in FIG. 6, a shield box 1 that is cooled to an extremely low temperature with liquid nitrogen or the like and an outer casing 2 that is a vacuum container.
The shield box 1 is configured to have a double box structure, and the equipment 3 which is kept in a cryogenic state by liquid helium or the like is housed in the shield box 1.

In addition, in this cold box, a device supporting tool 4 for supporting the devices 3 at a specific position in the shield box 1,
Further, a plurality of box supports 5 for supporting the shield box 1 at a specific position in the outer casing 2 are provided. Reference numeral 6 denotes a supply pipe for supplying a cooling medium such as liquid helium to the devices 3.

By the way, the equipments 3 are set in a cold box at room temperature and then cooled to a predetermined extremely low temperature for use. In this case, the cold box is also cooled from normal temperature to extremely low temperature, but since the respective support members 4 and 5 contract in this cooling process, the height position of the accommodated devices 3 changes.
Therefore, in the case where the instruments 3 need to be securely held at a specific height position such as a pellet injection device of a nuclear fusion experimental reactor or a measuring instrument, some position adjusting means is required. .

Conventionally, as this position adjusting means, the height position of the equipment 3 is at a predetermined level L (a level from here with the bottom wall of the outer casing 2 as a fixed wall) in a cryogenic state shown in FIG.
In order to reach the above condition, the lengths of these support members 4 and 5 are set at room temperature in FIG.

[Problems to be solved by the invention]

However, according to this means, although the object of the present invention of holding the devices 3 at a predetermined height position at an extremely low temperature can be achieved, as a harmful effect, the devices 3 move downward during cooling, A connecting body that connects the devices 3 and devices that are placed outside and used at room temperature (for example, in the case of the pellet injection device of the fusion experimental reactor described above, a guide tube that guides the pellet to the reactor) 7 Unreasonable load acts on. For this reason, there has been a problem that the connector 7 is specified as having flexibility so as not to be damaged.

On the other hand, as another means, as shown in FIG. 7, it is conceivable to horizontally install the equipment support 8 so that the equipment does not move up and down. Since it is necessary to give the lever support 8 high strength, the support 8 becomes heavy and expensive.

Therefore, the present invention provides a cold box capable of supporting devices at a predetermined height position without vertically moving in the cooling process on the premise of a vertical support system.

[Means for solving the problem]

The present invention is configured in a multiple box structure composed of a plurality of inner and outer boxes, in which the equipment used at cryogenic temperature is housed in the innermost box, and the above equipment is vertically arranged in the innermost box. In a cold box provided with a support for supporting in a direction and a support for supporting the box in a vertical direction inside the box outside the box, as the support, in the cooling process from room temperature to very low temperature of the equipment. A descending side support tool that contracts in a direction of lowering the supported body supported by each, and an ascending side support tool that contracts in a direction of raising the supported body are provided, and the supported body descends by these descending side support tools. The amount of contraction of each support tool is set so that the amount of lift and the amount of lift of the supported body by the lift-side support tool are substantially the same.

[Action]

With this configuration, during cooling, the descending 4 minutes of the supported body (equipment and box) by the descending side support and the rising amount of the supported body by the ascending side support are offset, resulting in the height of the equipment. The position is kept at the set height position at room temperature. That is, the devices are supported at a predetermined height position without moving up and down during the cooling process.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. In the following embodiments, the same parts as those of the conventional cold box shown in FIGS. 6 and 7 are designated by the same reference numerals, and the duplicate description thereof will be omitted.

First Embodiment (See FIGS. 1 and 2) 9 is a device support tool as a descending side support tool, and 13 is a box support tool as an ascending side support tool.

The device support tool 9 comprises flanges 11 and 12 attached to both upper and lower sides of a cylindrical main body 10 that serves as a main contracting part in the cooling process. In the lower part of the shield box 1, the upper flange 11 is vertically installed. Lower flange on the bottom of the equipment 3
12 are attached to the inner surface of the bottom wall of the shield box 1, respectively. Therefore, the devices 3 are attached to the device supporter 9.
The weight acts as a vertical compressive load, and the devices 3 descend due to the main body 10 contracting mainly during the cooling process.

On the other hand, the box support 13 includes a tubular member 14 and a rod-shaped member 15.
It is constituted by and.

The tubular member 14 has a bottom wall 14a and an upper end flange portion 14b, and in a state of vertically penetrating the bottom wall of the outer casing 2, the upper end flange portion 14b.
14b is supported on the bottom wall of the casing via the mounting seat 2a.

The rod-shaped member 15 is fitted into the tubular member 14 from the upper side, and the upper end is attached to the outer surface of the bottom wall of the shield box 1 while the lower end is supported by the member bottom wall 14a. 16 is a heat insulating cover.

Therefore, in the box support 13, the total weight of the shield box 1 and the devices 3 acts on the rod-shaped member 15 as a vertical compressive load and on the tubular member 14 as a tensile load. That is, during the cooling process, the rod-shaped member 15 contracts in the direction of lowering the shield box 1, and the cylindrical member 14 contracts in the direction of raising them.

Therefore, in the cooling process, the shrinkage amount of the tubular member 14 that is the rising side member of the box support 13 (the rising amount of the shield box 1) Δl ₂ is the shrinkage amount of the rod member 15 that is the falling side member ( The descending amount of the shield box 1) Δl ₃ and the difference (Δl ₂ −Δl ₃ = the rising amount of the devices 3) is the contraction amount (devices) of the device supporting member 9 which is the descending side supporting device. 3 of descent amount) .DELTA.l ₁ almost the same (Δl ₁ ≒ Δl ₂ -Δ
By setting the shrinkage amount of each of these members in advance so as to satisfy l ₃ ), the height position of the equipment 3 can be maintained at the set position at room temperature even at an extremely low temperature after cooling. it can. That is, the vertical movement of the devices 3 during the cooling process can be prevented. In the case of this support structure, as in FIG. 6, the bottom wall of the outer casing 2 serves as a fixed reference surface at the equipment setting level.

Here, the shrinkage amounts Δl ₁ , Δl ₂ , and Δl ₃ of each member can be determined by the shrinkage rate and the length dimension that are determined by the material of each member if the temperature of each member in use is determined. In this case, since the temperature of each member is low on the center side of the cold box and high on the outside, it is needless to say that it is necessary to calculate the shrinkage amount in consideration of this temperature distribution.

Therefore, the shrinkage amounts Δl ₁ , Δl ₂ , and Δl ₃ of each member are expressed as follows.

Here, i is a division number when each member is divided into a plurality in the length direction according to the temperature distribution, and ε is a linear expansion coefficient (shrinkage rate).
It is.

Further, ΔTxi = Txi−T ₀ , Txi is the temperature at each divided portion, and T ₀ is the room temperature reference value.

 Further specific examples are shown below.

In this example, the average temperature is calculated from the temperature distribution of each member, and this is used as the basis for calculation.

I. Equipment support 9 (a) Material: Teflon (b) Length at normal temperature l ₁ : 65mm Since the contraction amount of the upper and lower flanges 11 and 12 is minute, this flange length Without considering this, as shown in FIG. 2 (a), the contraction amount was obtained with only the length dimension of the main body 10 as the support dimension.

(C) Temperature: 300K at room temperature, upper side = 6K, lower side = 80K, average 43K (d) Shrinkage Δl ₁ : 65 x (20.2 / 1000) = 1.31mm II. Box support 13 cylindrical Member 14 (a) Material: Teflon (b) Length at normal temperature l ₂ : 143 mm (c) Temperature: At normal temperature 300K When used, upper side = 90K, lower side = 300K, average 195K (d) Shrinkage Δl ₂ : 143 × (13.0 / 1000) = 1.86mm III. Bar-shaped member of box support 13 15 (a) Material: Stainless steel (b) Length at room temperature l ₃ : 199mm (c) Temperature: At room temperature 300K the upper 80K, the lower 90K, average 85K (d) shrinkage amount _{Δl 3: 199 × (2.7 /} 1000) = 0.54mm Therefore, the _{Δl 1 (1.31) = Δl 2} (1.86) -Δl 3 (0.54) .

Second Embodiment (see FIG. 3) Only the differences from the first embodiment will be described.

In the second embodiment, a support 17 having basically the same structure as the box support 13 of the first embodiment is used as a device support, and a support 20 having the same structure as the device support 9 of the first embodiment. Are provided as box supports. Reference numeral 18 is a tubular member of the device supporting tool 17, 18a is a bottom wall of the member 18, 18b is an upper end flange portion, 19 is a bar-shaped member, 21 is a tubular main body of the box supporting tool 20, and 22 and 23 are upper and lower. It is a flange.

Also with this configuration, basically the same operation as in the case of the first embodiment can be obtained.

Third Embodiment (see FIG. 4) In the third embodiment, an equipment support 24 having basically the same structure as the equipment support 17 of the second embodiment and a box support 20 of the second embodiment. A box support 27 having the same structure is provided on the upper side of the cold box, and the devices 3 and the shield box 2 are suspended by these.

In this case, the tubular member 25 of the equipment support 24 is formed into a simple bottomless tubular shape, and the upper end portion of the rod member 26 is locked to the upper end surface of the tubular member 25. 28 is a main body of the box support 27, and 29 and 30 are upper and lower flanges.

According to this configuration, the rod-shaped member 26 and the box support 27 of the equipment support 24 are pulling members and are rising side support members that raise the equipment 3 and the shield box 2 by contraction, and the tubular member 25 is compressed. The member serves as a descending side supporting member that descends the devices 3 by contraction.

Fourth Embodiment (see FIG. 5) In the fourth embodiment, the equipment supports 9 of the first embodiment and the supports 31, 32 having the same structure as the box supports 20, 27 of the second and third embodiments. One of the supports 31 is used as a device support for the compression member between the bottom wall of the shield box 2 and the devices 3, and the other support 32 is used as a tension member for the box support 1 and the shield box 1. Equipment 3 provided by being respectively provided between the outer casing 2 and the equipment support 31 by contraction of the equipment support 31.
The descending amount of is shielded by the ascending amount of the shield box 1 due to the contraction of the box support 32. Reference numeral 33 is a tubular main body of both support members 31, 32, and 34, 35 are upper and lower flanges.

According to this structure, the structure of the supporting tool is simplified as compared with the first to third embodiments.

In the case of both the third and fourth embodiments, the upper wall of the outer casing 2 serves as a fixed reference surface at the equipment setting level.

By the way, in each of the above-mentioned embodiments, the shield box having the double box structure including the shield box 1 and the one outer casing 2 is applied as an example, but the present invention is not limited to this.
It can also be applied to a cold box having a triple or more box structure in which a box for housing devices is covered with two or more boxes. In this case, the descending-side support tool and the ascending-side support tool are provided in an appropriate distribution between the adjacent box bodies, and the total of the descending amount and the ascending amount of the supported object (equipment or box) due to the contraction thereof is substantially the same. The contraction amount of each support may be set so that

〔The invention's effect〕

As described above, according to the present invention, in a cold box having a multi-box structure, the devices for supporting the devices in the innermost box and the devices for supporting the box in the outer box are the devices. A combination of two types of support tools, a descending side support tool that contracts in the direction of lowering the supported body in the cooling process from room temperature to an extremely low temperature, and an ascending side support tool that contracts in the direction of raising the supported body , Since the amount of contraction of each support is set so that the total of the amount of lowering of the supported body by the descending side support and the amount of raising of the supported body by the ascending side support are approximately the same, during cooling, The descending amount of the supported body by the descending side support tool and the rising amount of the supported body by the ascending side support tool are offset.

Therefore, the devices are held at the set height position at room temperature without moving up and down during the cooling process. Therefore, as in the case of the conventional structure shown in FIG. 6, due to the movement of the equipment during cooling, it is not possible for the connecting body connecting the equipment and the equipment used at room temperature to be placed outside. There is no problem such that the load acts and the connector is broken by this, or the connector is specified as having flexibility so that the connector is not damaged.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of the present invention, FIG. 2 (a) is a partially enlarged view of FIG. 1, and (b) is cooling from an ordinary temperature state to an extremely low temperature state in (a). FIG. 3 is a diagram showing a changed state of each member after the operation, FIG. 3 is a second embodiment of the present invention, FIG. 4 is a diagram corresponding to FIG. 2 (a) showing the same third embodiment, and FIG. A fourth embodiment of the invention corresponding to FIG. 1 and FIG. 6 (a)
Is a vertical cross-sectional view showing a conventional example, (b) is a diagram showing a change state of each member after being cooled from a room temperature state to an extremely low temperature state in (a), and FIG. 7 is a vertical cross-sectional view showing another conventional example It is a figure. 1 ... Shield box as the innermost box, 2 ...
… Outer casing as a box covering the shield box, 3 …… Devices, 9,20,24,31 …… Descent side support, 13,1
7,27,32 …… Supporting equipment on the ascending side.

Front page continuation (72) Inventor, Tsuneo Yamada 1-13-10, Sawano, Akashi-shi, Hyogo (56) References JP-A-1-289179 (JP, A) JP-A-63-261706 (JP, A) Actual Kaihei 2-124464 (JP, U)

Claims (1)

(57) [Claims] 1. A multi-box structure composed of a plurality of inner and outer boxes, in which the innermost box contains equipment used at cryogenic temperature, and the above-mentioned equipment is placed in the innermost box. In a cold box provided with a support tool for supporting in a vertical direction and a support tool for supporting a box body in a vertical direction inside the box body outside thereof, as the support tool, a cooling process from room temperature to very low temperature Are provided with a descending side support tool that contracts in the direction of lowering the supported body supported by the above, and an ascending side support tool that contracts in the direction of raising the supported body. A cold box, wherein the amount of contraction of each support is set so that the amount of lowering and the amount of rise of the supported body by the supporting device on the rising side are substantially the same.