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:
Apr. 23, 1996
Filed:
Sep. 20, 1994
Hans-Rudiger Doring, D-7050 Leipzig, DE;
Eberhard Hartmann, D-7060 Leipzig, DE;
Other;
Abstract
The invention relates to a method and an apparatus for individually detecting in ambient air a predetermined gaseous warfare agent, namely a poison gas of the class of organic sulfuric or phosphorous substances, and a predetermined interfering compound, e.g. another poison gas. First, light O.sub.2 reaction ions are generated from water and are added in a measuring chamber to a mixture of the agent and the ambient air. As a result, the O.sub.2 reaction ions will deposit on the heavy molecules of the agent in a spatially non-uniform distribution to generate quasi-molecular ions. An electrical field alternating about a zero line and having a predetermined basic frequency and an amplitude is generated within the measuring chamber. The resulting quasi-molecular ion current is measured and resulting current signals are processed. For distinguishing the agent from the interfering compound, an initial experiment is made for a standardized measuring chamber. During the initial experiment, the quasi-molecular current is determined as a function of the basic frequency, of the amplitude and of a plurality of asymmetries of the electrical field variation relative to the zero line. Each current determination is carried out separately for the agent and for the interfering compound. Then a first measurement on the mixture of ambient air, agent and interfering compound is made with a first one of the asymmetries and, subsequently, a second measurement on the mixture is made with a second one of the asymmetries. The measured signals of these two measurements are logically combined to extract an output signal indicative of the presence of the agent and of the interfering compound within the ambient air.