Fiber optic flame detection and temperature measurement system having one or more in-line temperature dependent optical filters
US5051590A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 6, 1989 |
| Grant date | Sep 24, 1991 |
| Priority date | — |
| Expiry date | Dec 6, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B17/12
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
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 …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.