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. 15, 1990
Filed:
Jul. 13, 1988
Thomas Reichert, Erlangen, DE;
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Abstract
An actively shielded, superconducting magnet of a nuclear magnetic resonance tomography apparatus has an inner coil system and an outer coil system connected in series to avoid an increase in the external field upon the quench of one of the coil systems. To avoid losing the protection of the shielding effect from external magnetic field disturbances, a superconducting current limiter having a low critical current-carrying capability is connected in the coil system to guide a difference current between the inner coil system and the outer coil system. To avoid an unwanted increase in the external field in the event of a quench of one of the coil systems, the current limiter becomes normally conductive in the presence of a current difference larger than a prescribed value.