Method of measurement
US4279512A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 25, 1980 |
| Grant date | Jul 21, 1981 |
| Priority date | — |
| Expiry date | Feb 25, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N15/0205
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of measuring mean particle size and/or standard deviation of particles involves illuminating a suspension of the particles with three beams of radiation of wavelengths R.sub.1, R.sub.2 and R.sub.3 and measuring the beam intensities passing through the suspension. The results are compared with those of the liquid medium free of particles and attenuation ratios of the beams at wavelengths R.sub.1 and R.sub.3 and at R.sub.2 and R.sub.3 are compared with previously calculated values for these ratios. This comparison enables the desired parameters to be obtained easily; preferably by using a spectrophotometer in which two or more optical densities at two or more wavelengths are compared simultaneously. The method is of particular use for aqueous suspensions of titanium dioxide pigment using wavelengths R.sub.1, R.sub.2 and R.sub.3 of 480 to 520 nanometers, R.sub.2 of 600 to 800 nanometers and R.sub.3 of 400 to 480 nanometers and not greater than (R.sub.1 -40) nanometers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.