Development of a Liquid Hydrogen Transfer Pump System with MgB₂ Wires^*1

Abstract

An electric pump composed of an MgB₂ motor is combined with superconducting level sensors using thin CuNisheathed MgB₂ wires to transfer liquid hydrogen. An impeller is attached to the lower end of a rotating shaft on the MgB₂ motor and covered with an outer casing to form a centrifugal pump. Then, the MgB₂ motor and impeller are placed vertically inside a cryostat with an infill of liquid hydrogen. A glass Dewar vessel is prepared to receive the liquid hydrogen transferred from the cryostat containing the MgB₂ motor. The MgB₂ sensors are used not only to detect the level of liquid hydrogen but also to control the electric pump on the basis of their pre-estimated calibration curves. By using the assembled pump system, the liquid hydrogen is successfully transferred from the cryostat to the glass Dewar vessel via a transfer tube. (Translation of the article originally published in Cryogenics 52 (2012) 615-619)