Dust measurement
US4420256A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 1981 |
| Grant date | Dec 13, 1983 |
| Priority date | — |
| Expiry date | Feb 12, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N15/0205
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for measuring substantially spherical particles, such as dust. Two signals are formed, one of which is an approximately linear function of the particle concentration independently of the particle diameter and the second one is an approximately linear function of the particle diameter independently of the particle concentration. In order to obtain these signals the particles are illuminated with light in a direction different from their direction of flow. At least two detectors are arranged in such a way that the light in the beam path from the light source (3) to the first detector (6) is substantially only influenced by scattering and by light absorption of the particles and that the light in the beam path from the light source to the second detector (7) passes substantially only via reflections against the particles. The two signals are formed by definite relations between the d.c. voltage components of the output signals of the detectors and the average value of the squared R.M.S. value of the a.c. voltage component of the output signal from one of the detectors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.