Method and apparatus for monitoring particles using back-scattered light without interference by bubbles
US5012119A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 19, 1989 |
| Grant date | Apr 30, 1991 |
| Priority date | — |
| Expiry date | May 19, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/4742
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for determining the amount and size of particles and bubbles in a liquid process medium. The invention comprises the steps of providing a collimated light source to generate a light beam of a known wavelength, and directing it to illuminate a liquid sampling volume within a cell positioned within a sensor housing constructed to collect the light scattered by particles and/or bubbles within the sample caused by the impingement of the light beam. The scattered light is then separated into forward, and/or right angle and back scattering portions, and converted into separate electrical signals for each scatter direction. Since the scattering coefficient is a direct function of the density of the sampling volume, the presence of bubbles reduces the density and the amount of radiation scattered in the backward direction. Using the level of scattering resulting from the liquid medium alone as a reference, particles and bubbles within the sampling volume each scatter radiation at a level that results in significant and substantially similar positive signals in the forward and/or right angle scattered channels. As a result bubbles and particles are not distinguishable…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.