The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 03, 1977
Filed:
May. 12, 1975
Hitachi, Ltd., , JA;
Abstract
A persistent current switch adapted to connect the ends of a superconducting coil together and to disconnect the ends thereof includes a vacuum casing and at least a pair of electrodes disposed in the vacuum casing in opposing relationship to each other. Each of the electrodes is provided with a highly conductive contact portion of high-purity metal having a very small resistivity at extremely low temperatures and with at least one superconducting contact portion of superconducting material in alignment with one another in the respective electrodes so that parallel current paths of the highly conductive contact portion and the superconducting contact portion may be simultaneously established when the electrodes are brought into contact with each other. The persistent current flows through the superconducting contact portion in the normal state, but the current is swiftly diverted to the highly conductive contact portion when the S-N transition takes place owing to the deterioration of the critical current value of the superconductor due to the sudden change in conduction current or the application of external magnetic field so that the rapid attenuation of the persistent current can be prevented.