Thermal cut-off equipment of high-temperature superconducting binary current lead

Abstract

The invention discloses thermal cut-off equipment of a high-temperature superconducting binary current lead, which comprises a liquid nitrogen tank and a liquid helium tank, wherein liquid nitrogen and liquid helium are respectively filled in the liquid nitrogen tank and the liquid helium tank. The invention is characterized in that the liquid helium tank is communicated with a current lead neck tube, and a high-temperature superconducting lead is arranged in the current lead neck tube; the middle part of the current lead neck tube is connected with a heat conducting disk which is embedded in a center hole of the liquid nitrogen tank, and the upper end surface and the lower end surface of the heat conducting disk are respectively connected fixedly with the tank wall of the center hole of the liquid nitrogen tank; a plurality of vertical through holes are arranged between the upper end surface and the lower end surface of the heat conducting disk and are respectively used as a current lead channel, a measuring lead channel and a cold helium returning channel; and a plurality of liquid nitrogen cooling tanks are arranged at the cylindrical side surface of the heat conducting disk along the horizontal direction, and the horizontal liquid nitrogen cooling tanks are communicated with the liquid nitrogen tank. The thermal cut-off equipment of the high-temperature superconducting binary current lead performs the characteristics of large potential heat and good heat sink effect in the process of liquid nitrogen cooling to improve the temperature margin of the high-temperature superconducting lead, thereby greatly increasing the operating stability and the security of the high-temperature superconducting lead, and reducing the heat leakage of the current lead, the measuring lead and the current lead neck tube for the liquid helium tank.

Description

technical field [0001] The invention relates to a high-temperature superconducting binary current lead wire cooling technology for a superconducting magnet, in particular to a high-temperature superconducting binary current lead thermal cut-off device. Background technique [0002] The heat leakage of the current lead feeding the superconducting magnet accounts for a relatively large proportion of the total heat leakage of the superconducting device. The heat leakage of the current lead is mainly composed of two parts: the conduction heat along the current lead from the room temperature environment to the low temperature environment and the Joule heat of the lead itself. . Under air-cooling conditions, due to the high thermal conductivity of copper, the conventional copper current leads have the theoretically optimal heat leakage from room temperature to 4.2K low-temperature environment when the design operating current and temperature are 4.2K (the optimal condition is cool...

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Problems solved by technology

However, for a superconducting magnet system with a large energizing current, the cooling power of the first-stage cold head of the refrigerator may not be enough to completely remove the heat load generated by the copper lead, resulting in the failure of the superconducting magnet to work normally;

[0005] 2. If liquid helium vapor cooling is used, in order to ensure the normal operation of the high temperature superconducting wire at the critical temperature, the evaporation of liquid helium is too high and uneconomical

If liquid nitrogen evaporative cooling is adopted, the cooling capacity of the cold helium gas return gas in the liquid helium tank cannot be fully utilized (because the current current lead cooling method determines that the cold helium gas will not be able to return gas from the current lead neck tube). Waste, in addition, because there is no cold helium return gas to cool the liquid nitrogen temperature zone, the heat leakage of liquid helium along the neck tube will also increase;

[0006] 3. If only liquid helium or liquid nitrogen is used for air cooling, the effect of binary current leads on reducing heat leakage is very limited

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