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:
Feb. 27, 1990
Filed:
Jan. 04, 1989
B Hubert Pinckaers, Bloomington, MN (US);
Honeywell Inc., Minneapolis, MN (US);
Abstract
A flame detector, for use with a photocell which produces a flame signal when the photocell is exposed to a flame, is used for detecting the presence of a flame. An input circuit is coupled to the photocell for receiving and buffering the flame signal. The buffered flame signal is filtered and amplified in a filter. An output circuit further amplifies the filtered flame signal providing an output flame signal. A switch is also used in the flame detector for substantially short circuiting the flame signal to a known value upon receiving a switch-close signal from either a test computer or from a hot refractory detection circuit. A flame-out condition is detected by the hot refractory detection circuit which generates an HRD signal causing the flame signal to be substantially short circuited to a known value thereby eliminating a false flame signal caused by hot refractory shimmering.