Method and apparatus for determining moisture content of materials
US5220168A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1992 |
| Grant date | Jun 15, 1993 |
| Priority date | — |
| Expiry date | Apr 16, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/3181
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Method and apparatus for determining moisture content of materials by irradiating a sample of unknown moisture content with a narrow frequency band of light at a first wavelength during a first time period and a narrow frequency band of light of a second wavelength during a second time period. The two wavelengths of light have different water absorptive characteristics, and therefore are reflected by varying degrees depending on the surface moisture on the material. The respective reflections are measured by a single common detector, and a value corresponding to the ambient light is subtracted from each measurement. A ratio of the resultant values is then correlated with data derived from precalibration measurements of samples of known moisture content.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.