G01F 3/223

Measuring the volume flow of fluids or fluent solid material wherein the fluid passes through the meter in successive and more or less isolated quantities, the meter being driven by the flow with measuring chambers which expand or contract during measurement having flexible movable walls, e.g. diaphragms, bellows for gases {characterised by drive mechanism for valves or membrane index mechanism with adjustment of stroke or timing; Calibration thereof; Testing}