Dry-type superconducting switch without liquid helium conduction magnet

Abstract

The utility model discloses a dry-type superconducting switch without a liquid helium conduction magnet, and relates to the technical field of magnetic resonance components. Comprising a switch cold conduction device, the switch cold conduction device is composed of a cylindrical installation inner cavity and an arc-sheet-shaped cold conduction bridge, a switch framework is arranged in the installation inner cavity, a superconducting coil is wound on the middle section of the switch framework, a heating sheet is arranged on the outer side of the superconducting coil, and one end, far away from the installation inner cavity, of the cold conduction bridge of the switch cold conduction device is connected with a cold source. In the using process, the superconducting switch is short in switching-on and switching-off time and high in response speed during excitation and field reduction; thermal power brought to other surrounding low-temperature parts is small, the critical temperature of the superconductor is well protected, and a large amount of refrigerant consumed like a traditional superconducting switch does not need to be used; and the performance of the superconducting wire material of the superconducting switch cannot be degraded due to high temperature generated by opening and closing the switch, so that the stable operation of a magnetic field is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of magnetic resonance components, in particular to a dry superconducting switch for a liquid-helium-free conduction magnet. Background Technique

[0002] Since the value of a liquid-helium-cooled superconducting magnet is very high, and secondly, the quench reaction of a superconducting coil cooled by liquid helium immersion is intense and poses great danger; currently, the development trend of superconducting magnets is towards conduction-cooled superconducting magnets, that is, liquid-helium-free superconducting magnets; the liquid-helium-free conduction-cooled superconducting magnet is convenient to install, has no risks and hazards brought by quenching, and is more economical and safe. Existing superconducting magnets use a refrigerant (liquid helium) to cool the superconducting coil so that the superconducting coil reaches the corresponding critical temperature. In order to make the superconducting magnet operate more stably, a closed-loop operation mode is often adopted. In the closed-loop operation, the superconducting switch is a key component. The role of the superconducting switch in the superconducting magnet is to form a closed loop for the magnet to operate in a state of no loss or very slow magnetic field attenuation, so as to disconnect the external power supply to reduce the heat leakage of the magnet, thereby reducing the volatilization of liquid helium. In order to achieve closed-loop operation, the superconducting switch should have superconducting characteristics, and at the same time be able to normally convert between the superconducting state and the normal state and remain stable, generate a magnetic field and store energy.

[0003] In a liquid-helium-free conduction-cooled magnet, for the main coil of the superconducting magnet and the superconducting switch, since there is no liquid-helium refrigeration capacity as a low-temperature buffer, its local and short-term refrigeration capacity is much smaller than that of a liquid-helium-immersed magnet. The traditional superconducting switch is in a continuous heating state during the excitation process, while in a liquid-helium-free magnet, this heating state is likely to cause the magnet to heat up, destroy the critical temperature, and lead to quenching. Therefore, we provide a dry superconducting switch for a liquid-helium-free conduction magnet. Content of the Utility Model

[0004] The purpose of the utility model is to provide a dry superconducting switch for a liquid-helium-free conduction magnet.

[0005] The technical problem solved by the utility model is: how to protect the critical temperature of the superconducting switch from being destroyed without using a large amount of refrigerant, so that it can stably maintain the superconducting state without being affected by the temperature gradient during the use in the superconducting state.

[0006] The utility model can be realized by the following technical solutions: a dry superconducting switch for a liquid-helium-free conduction magnet, including a switch cooling device. The switch cooling device is composed of a cylindrical installation inner cavity and an arc-shaped cooling bridge. A switch skeleton is arranged inside the installation inner cavity. A superconducting coil is wound in the middle section of the switch skeleton. A heating sheet is arranged outside the superconducting coil. One end of the cooling bridge of the switch cooling device far away from the installation inner cavity is connected with a cold source.

[0007] A further technical improvement of the present utility model lies in that: one end of the switch skeleton is provided with a coil lead port for the lead arrangement and fixation of the superconducting coil, and a heater lead port is also opened at a position on the switch skeleton on the same side as the coil lead port.

[0008] A further technical improvement of the present utility model lies in that: the installation inner cavity of the switch skeleton and the switch cryogenic cooling device is connected by a thermally conductive insulating adhesive.

[0009] A further technical improvement of the present utility model lies in that: the switch skeleton is made of a metal material with good thermal conductivity.

[0010] A further technical improvement of the present utility model lies in that: the superconducting coil and the heating sheet are respectively electrically connected to an external excitation power supply and an external independent heating power supply.

[0011] A further technical improvement of the present utility model lies in that: a heat insulation plate is provided at the bottom of the switch cryogenic cooling device, and at least one switch clamp is used to fix the switch cryogenic cooling device on the heat insulation plate.

[0012] Compared with the prior art, the present utility model has the following beneficial effects:

[0013] During the use of the present utility model, the opening and closing times of the superconducting switch during excitation and field reduction are short, and the response speed is fast; the thermal power brought to other surrounding low-temperature components is small, which can well protect the critical temperature of the superconductor, and there is no need to consume a large amount of refrigerant like traditional superconducting switches; moreover, the opening and closing of the switch will not generate a very high temperature to cause the performance degradation of the superconducting wire material of the superconducting switch, so as to ensure the stable operation of the magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For the convenience of those skilled in the art to understand, the present utility model will be further described below in conjunction with the drawings.

[0015] Figure 1 It is a schematic diagram of the overall assembled structure of the present utility model;

[0016] Figure 2 It is a schematic diagram of the switch skeleton structure of the present utility model;

[0017] Figure 3 It is a schematic diagram of the switch clamp structure of the present utility model;

[0018] Figure 4 It is a schematic diagram of the heat insulation plate structure of the present utility model;

[0019] Figure 5 It is a schematic diagram of the switch cryogenic cooling device structure of the present utility model.

[0020] In the figure: 2. Switch superconducting wire winding groove; 3. Heater lead outlet; 4. Switch skeleton; 5. Coil lead outlet; 7. Switch clamp; 8. Heat insulation plate; 9. Switch cooling device. Detailed implementation mode

[0021] To further elaborate on the technical means and effects adopted by the present utility model to achieve the predetermined utility model purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation mode, structure, features and their effects of the present utility model as follows.

[0022] Please refer to Figures 1-5 As shown, a dry superconducting switch for a liquid-helium-free conduction magnet includes a switch skeleton 4. In the middle of the switch skeleton 4, there is a switch superconducting wire winding groove 2. The switch superconducting wire winding groove 2 is tightly wound with a superconducting coil. One end of the switch skeleton body 4 is provided with a coil lead outlet 5 for arranging and fixing the leads of the superconducting coil. At the same time, a heater lead outlet 3 is also opened at a position on the switch skeleton 4 on the same side as the coil lead outlet 5. A heating sheet is installed outside the superconducting coil, and the power lead of the heating sheet is arranged and fixedly connected to an external power supply through the heater lead outlet 3;

[0023] After winding the superconducting coil and installing the heating sheet on the switch skeleton 4, it forms a switch body. The switch body is arranged in the installation inner cavity of the switch cooling device 9, and the installation inner cavity of the switch cooling device 9 is adapted to the outer shape of the switch body;

[0024] The switch cooling device 9 further includes an arc-shaped cooling bridge arranged on one side of the installation inner cavity. A fixing hole connected to a cold source is provided at one end of the cooling bridge away from the installation inner cavity, so that the installation inner cavity of the switch cooling device 9 forms a cooling cavity. This cooling cavity provides a good low-temperature environment for the switch, which is beneficial to conductively cool the switch, so that during the process of raising and lowering the field of the dry liquid-helium-free magnet, the superconducting switch can freely perform the normal state and superconducting state conversion;

[0025] Furthermore, the switch cooling device 9 installed with the switch body is placed on the heat insulation plate 8, and at least one or more switch clamps 7 are used to fixedly connect the switch cooling device 9 and the heat insulation plate 8;

[0026] It should be noted that the switch skeleton 4 is processed from a metal material with good thermal conductivity, such as copper, aluminum alloy, etc.; a special thermal conductive insulating glue is used to connect the switch cooling device 9 and the switch body, such as epoxy resin, cryogenic glue.

[0027] When the present utility model is in use, when the superconducting magnet is electrified and excited, the heating sheet can be electrified and heated through an external power supply. At this time, the temperature of the superconducting coil rises, destroying the critical temperature of the superconducting coil and causing the superconducting switch to switch from the superconducting state to the normal state; when the current of the external excitation power supply enters the superconducting coil, the power supply of the heating sheet can be turned off, allowing the superconducting switch to generate heat by itself under the drive of the excitation power supply to maintain the normal state and continuously supply power to the magnet for excitation. After the magnet reaches the rated current, the self-heating of the switch stops. At this time, the switch cooling device 9 will conduct the cold quantity to the superconducting switch to reach thermal equilibrium, causing the superconducting switch to return to the superconducting state, enabling the magnet to maintain a constant current and stable energy storage;

[0028] During the excitation process, the large amount of heat generated by the superconducting switch will be transferred to the heat conduction bridge and cooled by the cold source, so that the heat will not be conducted to the superconducting coil joint through the heat insulation plate 8, making the superconducting joint not easily affected by heat, and very little heat is transferred to the superconducting coil to ensure the low-temperature stability of the magnet during the excitation process; at the same time, when the superconducting switch is in the superconducting state, since the superconducting switch is in the cooling cavity connected to the heat conduction bridge, external heat will not enter the switch, enabling the superconducting switch to be stable in the superconducting state without being affected by the temperature gradient during the use of the superconducting state.

[0029] The above are only the preferred embodiments of the present utility model and do not impose any form of limitation on the present utility model. Although the present utility model has been disclosed above with the preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes within the scope of the technical solution of the present utility model. However, as long as it does not depart from the content of the technical solution of the present utility model, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims

1. A dry superconducting switch for a liquid-helium-free conduction magnet, characterized in that, It includes a switch conduction-cooling device (9), which is composed of a cylindrical installation inner cavity and an arc-shaped conduction-cooling bridge. A switch skeleton (4) is arranged inside the installation inner cavity. A superconducting coil is wound around the middle section of the switch skeleton (4). A heating sheet is arranged outside the superconducting coil. One end of the conduction-cooling bridge of the switch conduction-cooling device (9) far away from the installation inner cavity is connected to a cold source.

2. The dry superconducting switch of a non-liquid-helium-conducting magnet according to claim 1, characterized in that, One end of the switch skeleton (4) is provided with a coil lead port (5) for the lead arrangement and fixation of the superconducting coil. A heater lead port (3) is also opened at a position on the switch skeleton (4) on the same side as the coil lead port (5).

3. The dry superconducting switch of a liquid-helium-free conduction magnet according to claim 1, characterized in that, The switch skeleton (4) is connected to the installation inner cavity of the switch conduction-cooling device (9) by a thermally conductive insulating adhesive.

4. The dry superconducting switch of a liquid-helium-free conduction magnet according to claim 1, characterized in that The switch skeleton (4) is made of a metal material with good thermal conductivity.

5. A dry superconducting switch for a liquid-helium-free conduction magnet according to claim 1, characterized in that, The superconducting coil and the heating sheet are respectively electrically connected to an external excitation power supply and an external independent heating power supply.

6. The dry superconducting switch of a liquid-helium-free conduction magnet according to claim 1, wherein A heat insulation plate (8) is arranged at the bottom of the switch conduction-cooling device (9), and at least one switch clamp is used to fix the switch conduction-cooling device (9) on the heat insulation plate (8).

Images