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, 1988
Filed:
Oct. 01, 1985
Tomohiko Sadakata, Kure, JP;
Shigeyoshi Kawano, Kure, JP;
Babcock-Hitachi Kabushiki Kaisha, Tokyo, JP;
Abstract
In a burner igniter using a ceramic heater, the resistance of the ceramic heater is detected to perform feedback control so that the temperature of the heater is maintained substantially constant to prevent both misfiring and overheating, while rapid temperature rise can also be obtained. The resistance value detected by a bridge circuit is fed to a proportional-integral controller which produces a control signal, while the current fed to the ceramic heater is also detected. The control signal and another signal indicative of the current to the ceramic heater are used to control a power source of the ceramic heater so that the current to the ceramic heater is controlled. A monitoring circuit responsive to both the resistance of the ceramic heater and the current fed to the ceramic heater may be added to warn a user that the life of the ceramic heater will soon end. The ceramic heater may comprise a portion having negative temperature coefficient, through which portion leak current would flow when the temperature of the ceramic heater rises so as to prevent overheating.