Beam forming and sensing apparatus for aerodynamic particle sizing system
US4938592A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 28, 1987 |
| Grant date | Jul 3, 1990 |
| Priority date | — |
| Expiry date | Jul 28, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2015/1493
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus, intended primarily for use in an aerodynamic particle sizing system, for generating a pair of closely-spaced, substantially parallel light beams and for determining particle sizes by measuring the times of flight of particles between the two light beams. The apparatus for generating the light beams includes a laser source, an aperture slit for establishing the shape of the beams, a cylindrical lens for focusing the laser beam on the aperture slit, a diffraction grating for converting the beam from the aperture slit into diffracted beams in the zero order lobe and one first order lobe and a transfer lens for directing the diffracted beams as substantially parallel beams. The particle measuring apparatus includes a prism, a lens arrangement for imaging light scattered by particles passing through one beam on a first face of the prism and for imaging light scattered by particles passing through the other beam on a second face of the prism that is perpendicular to the first face, and a pair of photomultiplier tubes for detecting light reflected by the faces of the prism. Start and stop pulses from the photomultiplier tubes are processed to determine particle time-of-flight w…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.