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:
Nov. 07, 1989
Filed:
Oct. 24, 1988
Donald L Ewing, Richardson, TX (US);
Forney International, Inc., Carrollton, TX (US);
Abstract
In an infrared flame detector system an infrared photodetector is positioned to receive infrared radiation from the flame to be detected. The output of the infrared flame detector is amplified with a gain readily switchable between two different gain values. The amplified output signal is filtered by a programmable high pass filter, in which the corner frequency can be selected to have different values and is readily switchable between two different values to correspond with different fuels generating the flame being detected. The output of the programmable filter is full wave rectified to provide a DC signal level corresponding to the AC signal generated across the photodetector. This DC signal level is compared with a reference signal voltage selected to correspond with the signal voltage produced when no flame is present, to provide an indication of the presence or absence of a flame.