Method and an apparatus for an air sample analysis
US5587581A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 31, 1995 |
| Grant date | Dec 24, 1996 |
| Priority date | — |
| Expiry date | Jul 31, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/623
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an apparatus for an air sample analysis, employing a dual polarity Ion Mobility Spectrometer (IMS), a method for stabilizing equilibrium conditions associated with the switching of the electric fields in the IMS cell comprises the steps of modulating a duty cycle of the electric field at the shutter grid located between the reactor region and the drift region of the IMS cell. During the switching of the electric fields at the cell, the open time of the duty cycle of the electric field at the shutter grid is extended. After the background polarity has been switched to the opposite polarity, the open time is returned to its normal value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.