Cryogen supply and return device for use with cryogen rotating electric machine and superconducting rotating electric machine with cryogen supply and return device

Abstract

Provided is a cryogen supply and return apparatus and a superconducting rotating electric machine, comprising stationary and rotatable members arranged out of contact with each other, preventing an increase of maintenance cost or a temperature increase of the cryogen which would be caused by contacts of the members. A cylinderhas on its outer peripheral surface ring-like recesses or grooves regularly or irregularly spaced in the longitudinal direction or spiral recesses or grooves continuously or discontinuously extending in the peripheral direction, to resist helium gas flowing through a cylindrical space between the cylinderand the inner tubeof the second double tube member and, as a result, to control a leakage of the helium gas from the cylindrical space.