A radially symmetric measurement chamber for electronic noses

A measurement chamber for the dynamic exposure of a sensor array to gaseous or liquid samples is presented. The device has been designed to optimise sensor response signals in terms of stability, reproducibility, response time and amplitude. This chamber has a radially symmetric flow splitter, which allows homogeneous flow conditions with low velocity gradients, and avoids significant recirculating zones and stagnant volumes. These characteristics, together with the fact that sample paths from the inlet to the sensors and from the sensors to the outlet have the same length, guarantee that all sensors are always exposed to the same chemical sample under the same experimental conditions. Through mathematical models, the introduction of a tracer in the form of a square wave concentration signal was simulated, and the effects of the working tolerances of the device main component on flow conditions were discussed. (c) 2004 Published by Elsevier B.V.