Method for detecting organic vapors and aerosols
US5874314A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1997 |
| Grant date | Feb 23, 1999 |
| Priority date | — |
| Expiry date | Jan 31, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/173845
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In a technique for detecting organic vapors and aerosols, e.g. of amines, hydrazines and nitrogen-containing compounds produced in combustion, molecules condense at a surface of a conductive device. By heating the conductive device in pulsed fashion, e.g. by resistance heating, condensed molecules are thermally ionized and emitted from the conductive device. Emitted ions are collected by a collector electrode, and the resulting ionic current pulse is amplified by a transimpedance circuit. The heat pulse lasts until the ionic current pulse has subsided, by which time the conductive device has become free of residual substances. As a result, the conductive device remains uncontaminated and has a long service life. The time-averaged power consumption of the technique is less than 2 mW. For resistance heating, a meander heater element can be disposed on a silicon nitride membrane across an etched opening in a silicon chip. A separate conductive surface layer can be included in the conductive device, separated from the heater element by an insulating layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.