An ionic flowmeter for measuring small rates of gas flow

A direct reading ionic discharge flowmeter capable of measuring rates of flow of gases from 0.30 mu g s-1 to 0.20 mg s-1 is described. The meter uses a differential current and voltage measurement arrangement. The meter functions best at a pressure of 4*102 Pa and has application for use with dry non-explosive gases. A semi-empirical model is devised to explain the theory of the instrument.