Optical emission line monitor with background observation and cancellation
US4616137A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 4, 1985 |
| Grant date | Oct 7, 1986 |
| Priority date | — |
| Expiry date | Jan 4, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2005/607
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium D-line emission in coal combustion, may be detected in the presence of interferring background or blackbody radiation with emissions much greater in intensity than that of the emission line being detected. A bifurcated fiber optic light guide is adapted at the end of one branch to view the combustion light which is guided to a first bandpass filter, adapted to the common trunk end of the fiber. A portion of the light is reflected back through the common trunk portion of the fiber to a second bandpass filter adapted to the end of the other branch of the fiber. The first filter bandpass is centered at a wavelength corresponding to the emission line to be detected with a bandwidth of about three nanometers (nm). The second filter is centered at the same wavelength but having a width of about 10 nm. First and second light detectors are located to view the light passing through the first and second filters respectively. Thus, the second detector is blind to the light corresponding to the emission line of interest detected by the first detector and the di…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.