Detection of Flammable and Explosive Liquids Inside Sealed Vessels Using Quasistatic Electrical Tomography

A. Korjenevsky

AVK Lab, Krjijanovskogo 15-5-504, Moscow, Russia, Email: avk@avklab.com

ABSTRACT

Combustible and explosive liquids become one of the main instruments of terrorists and organizers of street disorders. Until recently there were no means to detect dangerous liquids filled up, for example, in ordinary drink-bottles. Recently suggested microwave and optical detectors are not reliable because of unpredictable influence of the container's properties, and rather expensive. The handheld device CKAT, developed by the AVK Lab, is intended for checking of contents of various vessels, such as plastic and glass bottles, cardboard packages and other non-metallic containers. It provides detection of flammable and explosive liquids inside them without violation of sealing. The apparatus exploits the method of quasistatic electrical tomography. This method allows to estimate spatial distribution of electric properties of a medium and to determine characteristics of a liquid irrespective of the size of container, thickness of its wall or presence of air gap between the device and a vessel. In turn, the electrical properties of the liquid (permittivity and conductivity) enable to determine its flammability almost unambiguously. The sensor of the system is a linear array of electrodes. Usage of the multi- electrode electric field measurements enables us to estimate separately electrical properties of the wall and the liquid inside the bottle by solving the inverse problem for electric field. This provides very high detecting ability of the device: practically full absence of misses of dangerous objects and false alarms. The principle of operation, design and results of tests are presented.

Keywords contactless detection, security, liquid identification, electrical tomography