Dual spectrum infrared fire detector
First Claim
Patent Images
1. An electrical detection system responsive to a fire or explosion for generating an output signal, including in combination:
- a. long wavelength channel means responsive to radiant energy in a predetermined spectral band above about six microns of electromagnetic radiation and received from a fire or explosion for generating a first logic signal,b. short wavelength channel means responsive to radiant energy in a predetermined spectral band less than about two microns of electro-magnetic radiation and received from said fire or explosion for generating a second logic signal, andc. output gate means coupled to receive both said first and second logic signals and responsive thereto to generate said output control signal which may be further processed to control the suppression of said fire or explosion.
0 Assignments
0 Petitions
Accused Products
Abstract
Disclosed is a fire and explosion detection system wherein long wavelength radiant energy responsive signals are processed in one channel and compared to short wavelength radiant energy responsive signals which are processed in a second channel. When these signals are coincident in response to a fire or explosion of a predetermined threshold magnitude, an output fire suppression signal is generated.
27 Citations
21 Claims
-
1. An electrical detection system responsive to a fire or explosion for generating an output signal, including in combination:
-
a. long wavelength channel means responsive to radiant energy in a predetermined spectral band above about six microns of electromagnetic radiation and received from a fire or explosion for generating a first logic signal, b. short wavelength channel means responsive to radiant energy in a predetermined spectral band less than about two microns of electro-magnetic radiation and received from said fire or explosion for generating a second logic signal, and c. output gate means coupled to receive both said first and second logic signals and responsive thereto to generate said output control signal which may be further processed to control the suppression of said fire or explosion. - View Dependent Claims (2, 3, 4, 5, 8, 9, 11, 14, 15, 17, 18, 21)
-
-
6. a. said long wavelength channel means includes a thermal detector responsive to radiation in the far infrared region of the electromagnetic frequency spectrum, and
- 7. b. said short wavelength channel means includes a silicon photodetector responsive to short wavelength radiation in the near infrared region of the electromagnetic frequency spectrum, whereby short wavelength and long wavelength radiation changes are electrically compared before an output signal is generated.
-
12. An electrical system responsive to radiation generated by a fire or explosion including, in combination:
-
a. an optical filter for passing electromagnetic radiation in a predetermined wavelength range of the electromagnetic frequency spectrum, b. a thermopile detector optically coupled to said filter and responsive to ambient temperature changes induced by infrared radiation above 6 microns in wavelength and received from said filter for generating an output signal, and c. means for processing said output signal from said thermopile detector and for utilizing same to control the suppression of said fire or explosion/./, said signal processing means includes a frequency compensating amplifier stage coupled to said thermopile detector and which compensates for the roll off in responsivity of said thermopile detector.
-
-
16. A detection system for generating an output signal in response to a fire or an explosion and comprising:
- long wavelength channel means including a thermopile detector responsive to radiant energy in a predetermined spectral band above 6 microns wavelength of electromagnetic radiation and received from said fire or explosion, said long wavelength channel means further including a frequency compensating amplifier coupled to said detector and having a gain versus frequency characteristic selected to compensate for the roll off in responsivity of said thermopile detector and to thereby provide a substantially constant sensitivity to radiation received in a predetermined frequency range, and said long wavelength channel means further including means coupled to said frequency compensating amplifier for generating a logic signal capable of triggering means to suppress or control said fire or explosion.
- View Dependent Claims (19)
-
20. A process for detecting fires or explosions which includes the steps of:
-
a. sensing changes in incident short wavelength energy in the 0.7 - 1.2 micron range and resulting from said fire or explosion, b. simultaneously sensing changes in incident long wavelength energy in the 7 - 30 micron range and resulting from said fire or explosion, and c. electrically comparing the changes in incident short wavelength energy and long wavelength energy to thereby generate an output fire or explosion suppression signal once said changes simultaneously exceed a predetermined threshold level.
-
Specification