Towards a Gas Independent Thermal Flow Meter

We present a novel potentially gas-independent thermal flow sensor chip that contains three two-wire calorimetric flow sensors to measure the flow profile and flow direction inside a tube, and a single-wire flow(i)ndependent thermal conductivity sensor which detects the type of the gas through a simple DC voltage measurement. All wires have the same dimensions of 2000 mu m in length, 5 mu m in width and 1.2 mu m in thickness. Four different gases Ar, N-2, Ne and He were used for the thermal conductivity measurement and the measured output voltage corresponds very well with a theoretical model.