Dual beam maximum intensity laser sizing system
US4537507A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 18, 1982 |
| Grant date | Aug 27, 1985 |
| Priority date | — |
| Expiry date | Oct 18, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2015/145
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus and method for determining the size and velocity of particles, droplets and the like is disclosed. Laser beams of the same wavelength having different diameters are caused to cross and form an interference pattern. The scattered light caused by particles, droplets or the like passing through the interference pattern is sensed by a collection means. The scattered signal is passed through a high pass filtering means to isolate Doppler (AC) components, and a low pass filtering means to isolate a DC pedestal signal. The AC signal is processed to provide the velocity, and the DC signal is processed to provide the size of the particle, droplet or the like. The position of the AC Doppler components in the scattered signal indicates the position of the particle in the cross-section of the larger diameter beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.