The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 06, 1994
Filed:
Feb. 18, 1993
David K Davies, Churchill Borough, PA (US);
John M Zomp, North Huntingdon, PA (US);
Thermo King Corporation, Minneapolis, MN (US);
Abstract
A system for signalling the presence of selected ion species in a gaseous sample of an ion mobility sensor, having a unidirectional field provided between first and second electrodes positioned a selected distance apart. An ionization source generates ions in the sensor and a trigger controller allows ions to enter the region between the first and second electrodes at a time t.sub.1. The ions then arrive at the second electrode at a time t.sub.2. A transimpedance amplifier converts the ion charges to voltage signals. The presence of selected ion species is determined by circuitry that is activated by the trigger controller at t.sub.2. The species are preferably analyzed by directing the amplifier output to an analog to digital converter and then to a digital signal processor. The ions may alternatively be analyzed by generating a logic pulse representing a selected ion species when the amplifier output exceeds a preset value. An alarm signal is output when the logic pulse is coincident at an AND gate with a logic pulse representing the species' travel time from the first electrode to the second electrode.