Patent ID: 7511268

Claim:
Ion mobility spectrometer in which a measuring tube, a filter and a transport device are connected to form a circulatory gas system, with a gas inlet which introduces ambient gas for analysis to the measuring tube of the ion mobility spectrometer, wherein the measuring tube of the ion mobility spectrometer is connected with the ambient gas via a dosing channel, the circulatory gas system is connected with the ambient gas via an outlet channel, which is integrated into the circulatory gas system between a high-pressure side of the transport device and the measuring tube, the ambient gas to be analyzed is introduced into the measuring tube via the dosing channel at specified times for specified periods, and, during said specified times for specified periods, gas flows out of the circulatory gas system via the outlet channel and wherein gas flows out of the circulatory gas system via the dosing channel for a specified time when said gas is not flowing out of the outlet channel and cleans it, and there are no transport devices in either the dosing channel nor the outlet channel.