Apparatus for measuring charge on, and density of, airborne particulates
US4117715A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 5, 1977 |
| Grant date | Oct 3, 1978 |
| Priority date | — |
| Expiry date | Jul 5, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N33/0011
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A simple, inexpensive, hand-held and operated apparatus for providing a substantially immediate indication of the density of, and charge on, airborne particulate contaminants of a predetermined size or within a predetermined size range includes a first filter for removing particulate contaminants having a size greater than the maximum size of the range, and a second filter for passing all particulate contaminants having size smaller than the minimum size of the range. The two filters are arranged in series in a housing, and a hand-operated pump having a known capacity is used to draw contaminant-laden air through the series filters. A conductive screen is placed against the second filter to provide an electrical indication of the polarity of the charge on the contaminants trapped by the second filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.