JPH1123082A - Thermal switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal switch capable of effecting cooling surely and having a structure advantageous for size reduction. SOLUTION: In a thermal switch for low temperature application for effecting cooling against a superconductor coil by a refrigerator 11, a wedge-shaped thermal conductor 16 comprising a heat transfer side thermal conductor 16a for effecting heat transfer from the refrigerator 11 and a heat receiver side thermal conductor 16b disposed in contact with the heat transfer side thermal conductor 16a in such a manner that heat transfer is effected in a slidable state on the superconductor coil 10 from a position in contact with the heat transfer side thermal conductor 16a to a position whereat a clearance is formed between contact faces, a cylinder 18 fixed on the superconductor coil 10 and having a piston 20 connected with the heat receiver side thermal conductor 16b in its interior and having nitrogen gas (N2 ) enclosed in a hermetically sealed side by the piston are provided, and movement of the piston 20 according to conditions of the N2 gas changes connection state between the heat receiver side thermal conductor 16b and the heat transfer side thermal conductor 16a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a low-temperature thermal switch for a conduction-cooled superconducting coil.

[0002]

2. Description of the Related Art FIG. 2 shows a configuration diagram of a conventional low temperature thermal switch for a conduction cooling type superconducting coil.

As shown in FIG. 2, a thermal switch is provided with a high-temperature stage 3 and a low-temperature stage 6 in order to cool a conduction cooling type superconducting coil 1 by a refrigerator 2. The high-temperature stage 3 is for effectively utilizing the cooling capacity up to 80 ° K, and uses a nitrogen (N ₂ ) gas sealed in a pipe 7 provided between the high-temperature stage 3 and the superconducting coil 1. With the interposition, the superconducting coil 1 is cooled by convection and conduction of the N ₂ gas. High temperature stage 3
Is cooled to 80 ° K.

[0004] That is, when the superconducting coil 1 is cooled by the low-temperature stage 6, the N ₂ gas sealed in the pipe 7 is liquefied to be in a vacuum state. This is because there is no heat transfer. Thereafter, cooling of superconducting coil 1 is performed only by low-temperature stage 6.

[0005]

As described above, the conventional low-temperature thermal switch for the conduction-cooled superconducting coil 1 performs heat transfer with the N ₂ gas sealed in the pipe 7 interposed therebetween. In other words, there has been a method in which cooling is performed by conduction and convection due to N ₂ gas, and the stability of the cooling capacity is reduced. Therefore, the switching operation of the thermal switch was not stable. In addition, because of the structure in which N ₂ gas for heat transfer is sealed in the pipe 7, it has been difficult to reduce the size.

The present invention has been made in view of the above circumstances, and has as its object to provide a thermal switch having a structure capable of reliably performing cooling and advantageous for miniaturization.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a low-temperature thermal switch for cooling an object to be cooled by a refrigerator, and a heat-transfer-side heat transfer element for transferring heat from the refrigerator. And a heat-receiving-side transfer member that is in contact with the heat-transfer-side heat transfer member so as to perform heat transfer in a slidable state on the object to be cooled from a position in contact with the heat transfer-side heat transfer member to a position where a gap is formed in the contact surface. A heat transfer element composed of a heat transfer element and a piston fixed to the object to be cooled and connected to the heat receiving-side heat transfer element therein, and a nitrogen ( An N ₂ ) gas-filled cylinder, and sliding the heat-receiving-side heat transfer body in accordance with the movement of the piston according to the state of the nitrogen (N ₂ ) gas in the cylinder, The connection state with the heat-side heat transfer body is changed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a low-temperature thermal switch for a conduction-cooled superconducting coil 10 (cooling target) according to the present embodiment. Superconducting coil 10 is cooled by refrigerator 11 via a thermal switch.

As shown in FIG. 1, a thermal switch according to the present embodiment includes a low-temperature stage 12 and a high-temperature stage 1.
4, wedge-shaped heat transfer body 16, cylinder 18, piston 2
0, a piston rod 21 and an N ₂ gas pipe 22.

In order to cool the superconducting coil 10 with a refrigerator 11, a low-temperature stage 12 and a high-temperature stage 14 are provided. A wedge-shaped heat transfer body 16 is provided between the high-temperature stage 14 and the superconducting coil 10.

[0011] The wedge-shaped heat transfer body 16 is a heat transfer side heat transfer body 16.
a and the heat-receiving-side heat transfer body 16b. The heat transfer-side heat transfer body 16a is fixed so that heat is transferred to the high-temperature stage 14, and the heat-receiving-side heat transfer body 16b is located at a position where a gap is formed on the contact surface from the state of contact with the heat transfer-side heat transfer body 16a. The superconducting coil 10 is slidably contacted with the superconducting coil 10 so that heat is transferred.

The heat-receiving-side heat transfer body 16 is connected to a piston rod 21 for transmitting the movement of a piston 20 reciprocating in a predetermined direction within a cylinder 18 fixed to the superconducting coil 10. The heat receiving-side heat transfer body 16 b slides on the superconducting coil 10 in accordance with the movement of the piston 20 in the cylinder 18.

Heat transfer body 16a and heat transfer body 16
1B, as shown in FIG. 1, the shape when viewed from the side is a wedge shape, and the transmission surfaces 16c come into stable contact with each other when the switch is in the ON state shown in FIG. , FIG.
When the switch is turned off as shown in (b), the heat receiving-side heat transfer member 16b is slid toward the cylinder 18 to form a contact surface with such an inclination that a gap is formed between the heat transfer-side heat transfer member 16a and the contact surface. Have been.

The shape of the contact surface of each of the heat transfer side heat transfer body 16a and the heat reception side heat transfer body 16b is not particularly limited, but the same shape (completely both sides) so that heat transfer is performed efficiently. Is preferable).

The side of the cylinder 18 which is kept secret by the piston 20 (the side to which the piston rod 21 is not connected) is filled with nitrogen (N ₂ ) gas through an N 2 gas pipe 22. The side of the cylinder 18 where the N ₂ gas is not sealed is communicated with the atmosphere.

Next, the operation of the thermal switch of this embodiment shown in FIG. 1 will be described.

First, when the switch is turned on as shown in FIG. 1A, the refrigerator 11 transfers heat for cooling the superconducting coil 10 to the wedge-shaped heat transfer body 16 via the high-temperature stage 14.

In the switch ON state, the wedge-shaped heat transfer body 1
6 is in contact with the heat transfer surface 16c (inclined surface) of the heat transfer side heat transfer body 16a and the heat reception side heat transfer body 16b.
The cooling heat from the high-temperature stage 14 is conducted to zero. Since the heat transfer using the wedge-shaped heat transfer body 16 is performed by solid contact, cooling is performed more reliably.

Thus, the high-temperature stage 14 of the refrigerator 11
When the superconducting coil 10 is cooled to about 80 ° K by heat transfer through the wedge-shaped heat transfer body 16, the piston 2
N ₂ gas enclosed in the interior of 0 is a vacuum state in order to be cooled liquefied.

For this reason, a pressure difference is generated between the side of the piston 20 where the N ₂ gas is sealed and the side which is communicated with the atmosphere, and the piston 20 is moved in the direction of the arrow shown in FIG. The heat transfer body 16b moves in a direction to draw the heat transfer body 16b toward the piston 20 side.

The heat receiving side heat transfer member 16 b is moved on the superconducting coil 10 in accordance with the movement of the piston 20. Therefore, a gap is formed between the heat receiving side heat transfer body 16b and the heat transfer side heat transfer body 16a, and the switch is turned off as shown in FIG. 1B.

For this reason, cooling from the high-temperature stage 14 via the wedge-shaped heat transfer body 16 is not performed. That is,
Functions as a thermal switch.

As described above, the thermal switch of the present embodiment is replaced with a conventional thermal switch composed of a pipe container filled with N ₂ gas, and is replaced with one of a pair of wedge-shaped heat transfer members 16 that are in contact with inclined surfaces. The heat transfer side heat transfer body 16
a is fixed to the high-temperature stage 14 side, and the other heat-receiving-side heat transfer body 16b is installed on the superconducting coil 10 side so as not to impair heat transfer. Then, the piston 20 is moved according to the state of the N ₂ gas (vacuum state) by connecting to the piston in the cylinder 18 in which the N ₂ gas is sealed in the heat receiving side heat transfer body 16b on the superconducting coil 10 side. As a result, the heat receiving-side heat transfer member 16b is separated from the heat transfer-side heat transfer member 16a, so that a gap is generated in the contact surface, and the switch can be turned off.

For this reason, since the heat transfer is performed by solid contact, the heat transfer is more reliable than the conventional pipe system, and the heat transfer amount is large, which is advantageous for miniaturization.

[0025]

As described above in detail, according to the present invention, in a low-temperature thermal switch for cooling an object to be cooled by a refrigerator, a heat transfer side on which heat is transferred from the refrigerator. A heat transfer member that is in contact with the heat transfer member so that heat transfer is performed in a state where the heat transfer member is slidable from the state in contact with the heat transfer side heat transfer member to a position where a gap is formed in the contact surface; a heat transfer member composed of a side heat transfer member, fixed to the object to be cooled, a piston connected to said heat receiving side heat transfer inside is provided, N ₂ on the side where confidential is maintained by the piston A cylinder in which gas is sealed, and slide the heat-receiving-side heat transfer body in accordance with the movement of the piston according to the state of the N ₂ gas in the cylinder to change the connection state with the heat transfer-side heat transfer body Because the ON / OFF control of heat transfer is performed by mechanical operation In addition, more reliable operation can be obtained, and heat transfer is performed by solid contact, so that downsizing can be achieved as compared with the conventional pipe method.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a low-temperature thermal switch according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional low-temperature thermal switch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Superconducting coil 11 Low-temperature stage 12 Refrigerator 14 High-temperature stage 16 Wedge-shaped heat transfer body 16c Heat transfer surface 18 Cylinder 20 Piston

Claims (1)

[Claims] 1. A low-temperature thermal switch for cooling an object to be cooled by a refrigerator, comprising: a heat-transfer-side heat transfer body that transfers heat from the refrigerator; and a heat-transfer-side heat transfer. A heat receiving side heat transfer body that is in contact with the heat receiving side so as to perform heat transfer in a state of being slidable on the object to be cooled from a state of contact with the body to a position where a gap is formed in the contact surface. A heating element, a piston fixed to the object to be cooled, and connected to the heat-receiving-side heat transfer element therein, and a nitrogen (N ₂ ) gas sealed in a side where the airtightness is maintained by the piston; The heat receiving side heat transfer body is slid in accordance with the movement of the piston according to the state of the nitrogen (N ₂ ) gas in the cylinder, and is connected to the heat transfer side heat transfer body. A thermal switch characterized by changing a state.