Fiber optic flame detection and temperature measurement system having one or more in-line temperature dependent optical filters
Patent 5051590 Issued on September 24, 1991. Estimated Expiration Date: 
December 6, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 6, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2901740 3406389 3540041 3546689 3730259 3880324 Thermally activated electrochemical cell including an alkali metal salt solvate electrolyte High temperature sensor Energy conversion Method and apparatus for an optical sensor utilizing semiconductor filters InventorsAssigneeApplicationNo. 447494 filed on 12/06/1989US Classes:250/339.04, Including temperature determining means250/227.14, Condition responsive light guide (e.g., light guide is physically affected by parameter sensed which results in light conveyed to the photocell)250/339.05, With additional noninfrared wavelengths250/339.15, Sensing flame or explosion250/554, Flame light source340/578, By radiant energy374/161Change of optical propertyExaminersPrimary: Fields, Carolyn E.Assistant: Beyer, James Attorney, Agent or FirmInternational ClassG01J 001/00AbstractA 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.Other References
Field of SearchCondition responsive light guide (e.g., light guide is physically affected by parameter sensed which results in light conveyed to the photocell)Light conductor With detection of fiber microbend caused by parameter affecting fiber Flame light source With spectral frequency/wavelength discrimination Methods Flame By radiant energy Thermal By thermally emitted radiation With radiation conducting element Nonelectrical, nonmagnetic, or nonmechanical temperature responsive property Change of optical property | |
