CN102789865B - Conduction-cooled structure of superconducting magnet - Google Patents

Abstract

A cooling structure for a superconducting magnet, comprising a secondary cold head of a refrigerator (1), an inner superconducting coil (2), an outer superconducting coil (3), a magnet end plate (4), a cooling cylinder (5) and Conductive cold belt (6). The cooling strip (6) is composed of multiple bundles of oxygen-free copper strips. One end of the cold conduction belt (6) is welded to the secondary cold head (1) of the refrigerator, and the other end of the cold conduction belt (6) is welded to the magnet end plate (4). The cooling tube (5) is two semicircular thin-walled cylinders with symmetrical structure. The cooling cylinder (5) is located between the inner superconducting coil (2) and the outer superconducting coil (3), and the cooling cylinder (5) is connected to the secondary cold head (1) of the refrigerator through the cooling belt (6). The whole superconducting magnet is fully cooled by the cooling tube (5), and the temperature distribution of the magnet is uniform.

Description

A cooling structure of a superconducting magnet

technical field

The invention relates to a cooling conduction structure of a superconducting magnet.

Background technique

The continuous development of new materials and low-temperature technology has accelerated the application of superconducting technology. The unique physical properties of superconductors have incomparable application advantages compared to other materials, such as zero resistance effect, that is, unimpeded current-carrying capacity and so on. Traditional electromagnets are difficult to achieve or require a lot of energy and resources to achieve high magnetic fields, but using the zero resistance effect of superconductors can easily form a magnetic field of 1-10T through superconducting magnets. With the development of refrigeration equipment, the cooling method of superconducting magnets is also constantly changing. Superconducting magnets that are directly cooled by a refrigerator are generally called conduction cooling superconducting magnets. Conduction cooling superconducting magnets are refrigerated by refrigerators instead of the traditional necessary Cryogenic liquid refrigeration not only reduces the volume of the superconducting magnet system equipment and has a simple structure, but also greatly reduces the complexity of previous operations such as infusion. At present, the cooling power of the refrigerator is generally 1.5 watts at a temperature of 4.2K. For superconducting magnets, when the cooling power is fixed, the minimum temperature of the magnet and the uniformity of temperature distribution are determined by the heat leakage of the magnet and the cooling conduction of the magnet. Structural decisions. Therefore, designing a reasonable cooling structure is of great significance for the development of high-performance and high-stability superconducting magnets.

Contents of the invention

In order to overcome the shortcomings of low cooling efficiency and uneven heat transfer of existing superconducting magnets, the present invention proposes a cooling structure for superconducting magnets. The invention has the advantages of simple structure, easy manufacture, sufficient cooling of the whole magnet, uniform temperature distribution of the magnet and the like.

The cooling structure of the present invention comprises a secondary cold head of a refrigerator, a cooling belt, an inner superconducting coil, an outer superconducting coil, a cooling tube and a magnet end plate.

One end of the cold conduction belt of the present invention is connected to the secondary cold head of the refrigerator, and the other end of the cold conduction belt is divided into two parts, one of which is welded to the end plate of the magnet, and the other part is welded to the wall of the cold conduction cylinder. The conduction strip is composed of multiple bundles of oxygen-free copper strips.

The cooling tube of the present invention is made of oxygen-free copper material, and the cooling tube is two semicircular thin-walled cylinders with symmetrical structure.

The cooling tube of the present invention is placed on the outer surface of the inner superconducting coil, and the axial length of the cooling tube is equal to the axial length of the inner superconducting coil. The cooling cylinder is coaxial with the inner superconducting coil and the outer superconducting coil. From the inside to the outside are the inner superconducting coil, the cooling cylinder and the outer superconducting coil. The two axial end surfaces of the inner superconducting coil, the cooling tube and the outer superconducting coil are respectively closely attached to the inner surfaces of the two magnet end plates. The gap between the cooling tube and the inner superconducting coil is filled with glass ribbon and low temperature epoxy resin. The disc-shaped magnet end plates are located at both ends of the outer superconducting coil in the axial direction, the distance between the two magnet end plates is equal to the axial distance of the outer superconducting coil, and the outer diameter of the magnet end plates is larger than the outer diameter of the outer superconducting coil. path.

The outer surface of the cooling tube is wrapped with glass ribbon and brushed with low-temperature epoxy resin, and the thickness of the wrapped glass ribbon is greater than that of the outer superconducting coil. After the low-temperature epoxy resin is cured, the outer superconducting coil is wound at any position where the cooling tube is not exposed to the glass ribbon on the outer surface of the cooling tube by turning. Turning removes the glass ribbon at the part where the outer superconducting coil is not wound until the wall of the cooling cylinder is exposed.

In the present invention, one end of the cold conducting strip is connected to the secondary cold head of the refrigerator, and the other end of the cold conducting strip is connected to the exposed cold conducting cylinder wall without covering the glass ribbon.

The cooling tube of the present invention leaves a slit between the two semicircular thin-walled cylinders, which ensures that there is no contact between the two semicircular thin-walled cylinders. It is ensured that no induced eddy current occurs in the cooling tube when the superconducting magnet is excited.

The cooling method of the superconducting magnet of the present invention is to add a metal material cooling tube with good thermal conductivity between the inner superconducting coil and the outer superconducting coil, and then use the cooling belt to make the cooling tube and the secondary cold head of the refrigerator Connect to achieve rapid cooling and uniform temperature inside the magnet and the end plate of the magnet, and improve the electrification performance of the magnet.

The cooling structure of the present invention can achieve sufficient cooling of the inner superconducting coil and the outer superconducting coil, the overall temperature distribution of the magnet is uniform, and the operating performance of the magnet is stable.

Description of drawings

Fig. 1 Schematic diagram of the cooling structure of a superconducting magnet, in the figure: 1 the secondary cold head of the refrigerator, 2 the inner superconducting coil 3, the outer superconducting coil, 4 the magnet end plate, 5 the cooling cylinder, 6 the cooling belt;

Fig. 2 Schematic diagram of the structure of the cooling tube.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in FIG. 1 , the cooling structure of a superconducting magnet of the present invention includes a secondary cold head 1 of a refrigerator, an inner superconducting coil 2 , an outer superconducting coil 3 , a magnet end plate 4 , a cooling tube 5 and a cooling belt 6 . The cold conduction strip 6 is composed of multiple bundles of oxygen-free copper strips. The cooling tube 5 is two semicircular thin-walled cylinders with a symmetrical structure. The cooling tube 5 is placed on the outer surface of the inner superconducting coil 2 , and the axial length of the cooling tube 5 is equal to the axial length of the inner superconducting coil 2 . The two axial ends of the cooling tube 5 , the inner superconducting coil 2 and the outer superconducting coil 3 are closely attached to the inner side of the magnet end plate 4 . The disc-shaped magnet end plates 4 are located at both ends of the outer superconducting coil 3 in the axial direction, the distance between the two magnet end plates 4 is equal to the axial distance of the outer superconducting coil 3, and the outer diameter of the magnet end plates 4 is larger than the outer diameter of the outer superconducting coil 3. The outer diameter of the superconducting coil 3 . The gap between the cooling cylinder 5 and the inner superconducting coil 2 is filled with glass ribbon and low-temperature epoxy resin. A glass ribbon is wrapped on the outer surface of the cooling tube 5 and brushed with low-temperature epoxy resin, and the thickness of the glass ribbon wrapped is greater than that of the outer superconducting coil 3 . The outer superconducting coil 3 is wound at any position where the glass ribbon on the outer surface of the cooling tube 5 is removed by turning. Turn the glass ribbon at the position where the outer superconducting coil 3 is not wound until the cylinder wall of the cooling cylinder 5 is exposed. One end of the cold guide belt 6 is welded to the secondary cold head 1 of the refrigerator, and the other end of the cold guide belt 6 is divided into two parts, one part is welded to the magnet end plate 4, and the other part is connected to the exposed cold guide tube 5 by turning. Wall welded connections.

As shown in FIG. 2 , the cooling tube 5 is made of oxygen-free copper material, and the cooling tube 5 is two semicircular thin-walled cylinders with a symmetrical structure. The wall thickness of the cold guide tube 5 is 1mm. When the cooling tube 5 is installed, there is a slit without contact between the two semicircular thin-walled cylinders to ensure that no induced eddy current occurs in the cooling tube 5 when the superconducting magnet is excited.

Claims (5)

1. a superconducting magnet conduction structure, is characterized in that described superconducting magnet conduction structure comprises refrigeration machine secondary cold head (1), interior superconducting coil (2), outer superconducting coil (3), magnet end plate (4), conduction cooling cylinder (5) and conduction cooling band (6); Two semicircle thin cylinders that conduction cooling cylinder (5) is symmetrical structure; Conduction cooling cylinder (5) is placed on the outer surface of interior superconducting coil (2); Two axial end faces of conduction cooling cylinder (5) are close on magnet end plate (4) medial surface; The magnet end plate (4) of round pie is positioned at the two ends of outer superconducting coil (3) axis direction, and the distance between two magnet end plates (4) equals the axial distance of outer superconducting coil (3), and the external diameter of magnet end plate (4) is greater than the external diameter of outer superconducting coil (3); Gap-fill between conduction cooling cylinder (5) and interior superconducting coil (2) has glass tape and low temperature epoxy resin; At conduction cooling cylinder (5) outer surface, be tied with glass tape and be brushed with low temperature epoxy resin; Superconducting coil (3) outside the position coiling of glass tape of conduction cooling cylinder (5) outer surface is removed in turning, the position turning glass tape of superconducting coil outside there is no coiling (3) is until expose the barrel of conduction cooling cylinder (5); One end of conduction cooling band (6) is welded to connect at refrigeration machine secondary cold head (1), the other end of conduction cooling band (6) is divided into two parts, wherein a part is welded to connect with magnet end plate (4), and another part is welded to connect on the barrel of the conduction cooling cylinder (5) exposing in turning.

2. according to a kind of superconducting magnet conduction structure claimed in claim 1, between two semicircle thin cylinders of the conduction cooling cylinder (5) described in it is characterized in that, leave slit, contactless between two semicircle thin cylinders of conduction cooling cylinder (5).

3. according to a kind of superconducting magnet conduction structure claimed in claim 1, it is characterized in that the axial length of described conduction cooling cylinder (5) equates with interior superconducting coil (2) axial length.

4. according to a kind of superconducting magnet conduction structure claimed in claim 1, it is characterized in that described conduction cooling cylinder (5) is coaxial with interior superconducting coil (2) and outer superconducting coil (3); Two axial end faces of conduction cooling cylinder (5), interior superconducting coil (2) and outer superconducting coil (3) three are close to respectively on the medial surface of two magnet end plates (4).

5. according to a kind of superconducting magnet conduction structure claimed in claim 1, it is characterized in that being greater than the thickness of outer superconducting coil (3) at described conduction cooling cylinder (5) thickness of glass tape that outer surface is wound around.