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. 01, 1984
Filed:
Oct. 13, 1981
Paul G Friedmann, Madison, NJ (US);
Frank N Patris, Flemington, NJ (US);
Allan W Tomalesky, Somerville, NJ (US);
Electric Power Rsearch Institute, Inc., Palo Alto, CA (US);
Abstract
Improved and simplified measurement of the level of molten metal in a crucible heated by an induction coil utilizes a variable frequency power supply for the induction coil. Power supply frequency is changed to maintain the power provided to the coil substantially constant, independent of variations of power factor in the coil circuit. Detection of the frequency of power supplied to the induction coil provides an indication of the changes in power factor of the coil due to changes in the level of molten metal surrounded by the coil, and thus of the level of the molten metal.