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. 02, 1982
Filed:
Jul. 07, 1980
David N Ball, Slough, GB;
Graviner Limited, Buckinghamshire, GB;
Abstract
A system for discriminating between radiation produced by a source of fire or explosion to be detected and radiation produced by a source not to be detected comprises two radiation detectors respectively responsive to the intensity of radiation in different wavelength bands to product respective electrical outputs, one band being relatively broad and including the other which is relatively narrow. A rate of rise unit and a threshold unit responsive to the broad band detector produce signals of one binary type when the rate of rise of, and the value of, the intensity of the radiation received by that detector exceed predetermined values. A ratio unit measures the ratio of the intensities of the radiation respectively received by both detectors and produces a signal of the opposite binary type when the ratio indicates that the source of the radiation is a fire or explosion to which the system is not to respond. An AND gate produces a fire and explosion indicating output only when the signals of the first binary type exist in the absence of the signal of the opposite binary type.