Intelligent gas-mixture flow sensor

A simple way to realize a gas-mixture flow sensor is presented. The sensor is capable of measuring two parameters from a gas flow. Both the flow rate and the helium content of a helium-nitrogen gas mixture are measured. The sensor exploits two measurement principles in combination with (local) information handling in an artificial neural network. An analysis of the measurement principles is given and the IC-compatible realization process is described. The sensor is simple to integrate with other micro gas-handling components such as valves, pressure sensors, etc. The sensing elements are combined with a small electronic circuit in which the artificial neural network is implemented. The experimental results are very promising.