Method and apparatus for monitoring particulates using back-scattered laser with steerable detection optics
US5999257A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 5, 1998 |
| Grant date | Dec 7, 1999 |
| Priority date | — |
| Expiry date | Jan 5, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/4785
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In a method for monitoring particulates in stacks or ducts a back-scatter monitor uses a solid-state laser to emit a collimated beam, the intensity of which is controlled via feedback from a reference detector. The beam is split so that part goes to a reference surface for calibration checks, and part is directed to pass at a selected angle through a gaseous sample. Optical energy scattered from particles in the sample is detected by viewing optics to provide an indication of particulate concentration. The beam steering mechanism can direct the optics to view scattering along a selectable axis that intersects the laser beam at a specified location within the gaseous sample. The method can be used to determine the opacity of the gaseous sample providing a basis for correlation to particulate loading of that portion of the particulates that are of a size comparable to the wavelength of light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.