Patent ID: 9577504
Date: 2017-02-21
CPC Classifications: H02K,Y02E

Claim:
1. A cryogen supply and return apparatus for supplying a cryogen from a refrigerator to a superconducting rotating electric machine and returning the cryogen from the superconducting rotating electric machine to the refrigerator in order to cool superconducting coils in the superconducting rotating electric machine and maintain a superconducting property of the superconducting coils, the refrigerator having a cylindrical casing and the superconducting rotating electric machine having a cylindrical shaft and coupling, the cylindrical shaft and coupling of the superconducting rotating electric machine being inserted coaxially in the cylindrical casing of the refrigerator so that the cylindrical shaft and coupling are capable of rotating about a longitudinal axis of the superconducting rotating electric machine, the cryogen supply and return apparatus comprising: a first tube that is positioned along the longitudinal axis within the cylindrical casing of the refrigerator and fixedly supported by the refrigerator; a second tube that is positioned along the longitudinal axis and connected at one end thereof with a cryogen supply tube provided within the cylindrical shaft and coupling of the superconducting rotating electric machine and fixedly supported by the superconducting rotating electric machine so that the second tube rotates with rotations of the superconducting rotating electric machine, the first tube and the second tube being assembled with each other so that either (i) the first tube is inserted inside an other end of the second tube, or (ii) the other end of the second tube is inserted inside the first tube to define a first cryogen passage for supplying the cryogen from the refrigerator toward the superconducting rotating electric machine, and a gap between the first tube and the second tube; a third tube that is positioned along the longitudinal axis and around the second tube, within the cylindrical casing of the refrigerator, and fixedly supported by the superconducting rotating electric machine so that the third tube rotates with rotation of the superconducting electric machine and defines a second cryogen passage around the first tube and the second tube for returning the cryogen from the superconducting rotating electric machine toward the refrigerator, the second cryogen passage being connected with a cryogen return tube provided within the cylindrical shaft and coupling of the superconducting rotation electric machine; a fourth tube that is positioned along the longitudinal axis and around the third tube and fixedly supported by the superconducting rotating electric machine so that the fourth tube rotates with rotations of the superconducting rotation electric machine and defines a closed cylindrical space around the third tube, the fourth tube having a first port defined therein, the first port being configured to communicate with a vacuum exhaust device, the fourth tube being connected with the cylindrical shaft and coupling of the superconducting rotating electric machine to define a cylindrical chamber inside the cylindrical shaft and coupling of the superconducting rotating electric machine for receiving the cryogen supply and return tubes; an exhaust chamber that is fixedly supported by the refrigerator so that the exhaust chamber surrounds the fourth tube in a direction perpendicular to the longitudinal axis to fluidly communicate between the vacuum exhaust device and the first port; and a sealing mechanism that seals between the exhaust chamber and the fourth tube, wherein: