Santa Barbara Research Center

John M Wetzork

Gregory L Tangonan

Mark T Kern

Kenneth A Shamordola

A fiber optic fire and overheat sensor system 10 includes a fiber optic cable 12 having a lens 14 at a distal to direct radiation from a fire 16 into the cable 12 and to a radiation detector 18 disposed at a proximal end of the cable 12. Detector 18 is coupled to a fire sensor 19. The detector 18 is sensitive to two wavelength bands including a short wavelength band of approximately 0.8 to approximately 1.1 microns and a long-wavelength band of approximately 1.8 to approximately 2.1 microns. A controller 21, such as a microprocessor, analyzes the fire sensor 19 output signals which correspond to the two spectral bands to determine if a fire is present. The system 10 further includes a body of fluorescent material 20 disposed at the distal end of the cable 12. The material 20 can be interposed between a reflecting surface, such as a mirror 22, and a lens, such as a collimating lens 24. A fiber optic coupler 26 and 26a launches radiation from a source 28, such as a laser diode, into the fiber optic cable 12. The fluorescent material is pumped by the source 28 at a first wavelength, the rate of decay of a resulting fluorescent emission being measured and correlated with predetermined decay rates to derive the temperature of the material 20 and, hence, the ambient temperature of a region within which the material 20 is disposed.

Fiber optic flame and overheat sensing system with self test

A fiber optic fire detection and temperature measurement system 10 includes a fiber optic cable 12 having a lens 14 at a distal to direct radiation from a fire 16 into the cable 12 and to radiation detector 18 disposed at a proximal end of the cable 12. Detector 18 is coupled to a fire sensor 20. Detector 18 is sensitive to three wavelength bands including a short wavelength band of approximately 0.8 to 1.1 microns, a mid-wavelength band of approximately 1.3 to 1.5 microns and a long-wavelength band of approximately 1.8 to 2.1 microns. A controller 22, analyzes the fire sensor 20 output signals which correspond to the two spectral bands to determine if a fire is present. The fiber optic conductor is doped with a material selected for its temperature dependent fluorescent emission characteristics. Radiation from a fire passes via cable 12 to the detector 18. A pulse of radiation from source 28 passes from a coupler 26 and 26a to the cable 12. The fluorescent doping material within the fiber optic cable 12 is pumped by the pulse and is caused to fluoresce within the third wavelength band. A portion of the fluorescent emission passes back through the fiber 12 to the detector 18 where the fluorescent emission is detected and processed to determine the temperature.

Fiber optic flame detection and temperature measurement system employing

A fiber optic fire detection and temperature measurement system 10 includes a fiber optic cable 12 having a lens 14 at a distal to direct radiation from a fire 16 into the cable 12 and to a radiation detector 18 disposed at a proximal end of the cable 12. Detector 18 is coupled to a fire sensor 20. The detector 18 is sensitive to three wavelength bands including a short wavelength band of approximately 0.8 to 1.1 microns and a long-wavelength band of approximately 1.8 to 2.1 microns. A controller 22, analyzes the fire sensor 20 output signals which correspond to the two spectral bands to determine if a fire is present. The fiber optic conductor of cable 12 includes an optical filter 32 having a temperature dependent radiation transmission characteristic. Radiation from a fire passes via cable 12 to the detector 18. A dual wavelength pulse of radiation from a source 28 passes through the filter 32 where a reference wavelength, corresponding to one of the fire sensor spectral bands, passes through unimpeded while the other wavelength within a third spectral band is absorbed as a function of temperture. The detector includes third element 18c for detecting the third spectral band and includes circuitry 54 for determining the temperature of the coupler 30.

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Goleta, CA, United States of America

John M Wetzork