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:
Jun. 27, 1995
Filed:
Mar. 18, 1994
Thomas H McGaffigan, Half Moon Bay, CA (US);
Metcal, Inc., Menlo Park, CA (US);
Abstract
This invention provides a system for providing heating in an alternating magnetic field using lossy heat producing magnetic particles. This invention discloses a system comprising a combination of particles wherein the first particles are lossy heat producing particles, which have a preselected Curie temperature to provide self-regulating heating in the alternating magnetic field, and the second particles are nonlossy particles which have high permeability which are not heat producing particles but which maintain the coupling of the magnetic circuit and maintain the desired magnetic field focus and intensity through the area in which the first lossy heat producing particles are positioned. Thus, in this invention, when the first lossy heating particles approach or are at their Curie temperature and have declining permeability and would otherwise lose the desired coupling with the magnetic circuit, the second nonlossy high permeability particles maintain the coupling of the magnetic circuit as well as the desired intensity of the magnetic field through the first lossy heating particles to provide the desired field strength throughout the heating period. This invention prevents premature loss of heating due to loss of coupling of the magnetic circuit with the lossy heating particles and provide other advantages. This invention also provides magnetic particles coated with an electrically resistive coating, which coated particles exhibit useful properties in the above particle systems.