Magnetic refrigeration apparatus for He II production

摘要

A magnetic refrigeration apparatus (10) is modular in design, so that housing modules (14) are alternately stacked with superconducting magnet pairs (24). Each module (14) has a wheel (16) that is rotated through the module (14), the wheel (16) having cutout regions (18) into which elements (20) of magnetic material are inserted. Each cutout region has two elements (20) separated by a wave spring, the wave spring biasing the elements (20) against the housing module (14) so that the elements (14) are in slidable contact with the module (14) upon rotation. In operation, the wheel (16) carries the elements (20) cyclically between high and low magnetic field zones. In low field regions the elements (20) are cooled by the magnetocaloric effect and heat exchangers absorb heat from either a stagnant subcooled superfluid helium bath or a forced-flow subcooled superfluid helium stream. In high field regions the elements (20) are heated by the magnetocaloric effect and a force-flow stream of liquid helium passes through the high temperature heat exchangers absorbing heat from the magnetic refrigeration apparatus (10).