Method and apparatus for measuring particles in a fluid
US5257087A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 16, 1991 |
| Grant date | Oct 26, 1993 |
| Priority date | — |
| Expiry date | May 16, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N15/0205
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is a method and apparatus for measuring particles in a fluid by irradiating the fluid containing the particle with a laser beam and deriving particle characteristics such as diameter and size distribution from the intensity of the light scattered by the particles. Based on the value of the output of a photomultiplier used to detect the scattered light, it is determined whether a particle is a fine particle, which is a particle with a photoelectron pulse count that does not exceed a prescribed value, or a large particle, and these particles are counted separately. Fine particles are processed using photon counting, and large particles are processed by an analog process, in which case the threshold values used to discriminate particles are varied in accordance with pre-stored data on the refractive index of each fluid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.