Differential manometer with reflective optical sensor

Abstract

For the purpose of the identification and quantification of the plasma effect on gas flow rate in atmospheric pressure discharges there was a strong need for differential manometer for fine and precise measurements which is indifferent on the influence of the charged particles. Therefore, a differential manometer with a completely free membrane has been constructed. Manometer is based on the use of reflective sensor CNY70. The basic request, undisturbed measurement of small value of differential pressure, up to 10 Pa, is realized with satisfying sensitivity and accuracy. Furthermore, different ranges of differential pressures measurable with the constructed instrument have been achieved by use of membranes made of different materials and with different thicknesses. The best linearity showed membranes made of copper and rubber. By means of five different membranes, the complete range of pressures from 1 Pa to 100 kPa is covered with substantial overlap.