SUPERCONDUCTING MAGNET DEVICE

• US 20150270045A1
• Filed: 02/10/2015
• Published: 09/24/2015
• Est. Priority Date: 03/18/2014
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nakayama, Takeshi
• Granted Patent: US 9,620,272 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F25D 19/006 Thermal coupling structure or interface
• CPC Class Codes: H01F 6/04 Cooling
• CPC Class Codes: H01F 6/06 Coils, e.g. winding, insulating, terminating or casing arrangements therefor

Abstract

In the related-art methods for mechanically switching the heat transfer path to a permanent current switch, a heat transfer rod is made to contact a cooling stage simply by the force of a drive unit. These methods have a problem that an excessive load acts on a support rod which supports the cooling stage from the normal temperature side. There are conflicting problems that while it is difficult to thicken the support rod in view of the amount of heat penetration, a predetermined contact pressure is necessary in order to connect the heat transfer rod to the cooling stage. If a sufficient contact pressure cannot be achieved, the refrigeration capability needs to be increased, contributing greater cost. In view thereof a permanent current switch device of a refrigerator cooling-type superconducting magnet is provided so that a permanent current mode can be realized efficiently.

Claims

1. A superconducting magnet device comprising:

a refrigerator having a cooling stage;

a tubular former having a hollow structure;

a permanent current switch formed by a superconducting wire wound on the former;

a heater capable of heating the former;

a heat transfer member that can be inserted in the former which is thermally expanded, heated by the heater, and that has a smaller coefficient of thermal expansion than the former;

a good conductor connecting the heat transfer member and the cooling stage; and

a superconducting coil connected in parallel to the permanent current switch.

2. The superconducting magnet device according to claim 1, wherein a cross-sectional shape of the heat transfer member on a plane perpendicular to a vertical direction is

a similar figure to an inner-diameter cross section of the former, and equal to or smaller than the inner-diameter cross section of the former when thermally expanding, and greater than the inner-diameter cross section of the former when thermal contracting.

3. The superconducting magnet device according to claim 2, further comprising:

a thermal insulation support member connected to the heat transfer member; and

a drive unit which is connected to the thermal insulation support member and moves the heat transfer member via the thermal insulation support member;

wherein the drive unit moves the heat transfer member in such a way as to insert the heat transfer member into the former or extract the heat transfer member from the former when the former is expanding, heated by the heater.

4. The superconducting magnet device according to claim 3, wherein the cooling stage includes a high-temperature cooling stage and a low-temperature cooling stage,

the heat transfer member includes a first heat transfer member and a second heat transfer member,

the high-temperature cooling stage is thermally connected to the first heat transfer member,

the low-temperature cooling stage is thermally connected to the second heat transfer member, and

the first heat transfer member and the second heat transfer member are connected to the thermal insulation support member and arranged, spaced apart from each other by a longer length than a vertical length of the former.

5. The superconducting magnet device according to claim 2, wherein the heat transfer member is fixedly arranged in the follow part of the former.

6. A superconducting magnet device comprising:

a refrigerator having a cooling stage;

a permanent current switch formed by a superconducting wire wound on a former;

a heater capable of heating the permanent current switch;

a rod-like drive support having a stopper portion and a thread portion;

a nut-like member that meshes with the thread portion and can bind the cooling stage with the stopper portion by rotation of the drive support;

a heat transfer member provided between the stopper portion and the cooling stage;

a drive mechanism that rotates the drive support;

a good conductor connecting the heat transfer member and the former; and

a superconducting coil connected in parallel to the permanent current switch.

7. The superconducting magnet device according to claim 6, wherein the heat transfer member is installed on the stopper portion and has the distance thereof from the cooling stage adjusted by rotation of the drive support.

8. The superconducting magnet device according to claim 6, further comprising a fixing support that contains the drive support and is joined to the cooling stage,

wherein the fixing support has an inner diameter that is greater than a diagonal length of the nut-like member, and the fixing support has a prevention part at a position that is on the inner diameter side and substantially equal to the height of the nut-like member from an end portion.

9. The superconducting magnet device according to claim 7, further comprising a fixing support that contains the drive support and is joined to the cooling stage,

wherein the fixing support has an inner diameter that is greater than a diagonal length of the nut-like member, and the fixing support has a prevention part at a position that is on the inner diameter side and substantially equal to the height of the nut-like member from an end portion.