Particle sensor with cooled light trap and related method
US6091494A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 25, 1999 |
| Grant date | Jul 18, 2000 |
| Priority date | — |
| Expiry date | May 25, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N15/0205
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A particle sensor operates in ambient air at an ambient air temperature and includes (a) a light source projecting a beam of light, (b) a light trap aligned with the beam of light and comprising at least one light-energy-absorbing surface at a surface temperature, (c) a nozzle flowing particle-entraining air through the beam of light, and (d) an opto-electrical system detecting light scattered by a particle. In the improvement, the sensor includes a cooling apparatus in heat transfer relationship to the surface and absorbing heat from such surface. The surface temperature is maintained at or below a value which substantially eliminates thermally-induced electro-optical disturbances in the sensor. A new method for reducing electrical noise detected by an opto-electrical system in the particle sensor includes providing a cooling apparatus in heat transfer relationship to the surface and transferring heat from the surface to the cooling apparatus at a rate which limits the surface temperature to a value which substantially eliminates thermally-induced electro-optical disturbances in the sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.