Vane wheel fluid flowmeter - has vane wheel with marks on its front and two sensors delivering pulses whose ratio corresponds to that of vanes and marks

摘要

The vane wheel is mounted in a chamber through which the fluid flows, in which a stationary sensor is also mounted, delivering a counting pulse at each vane passage. A second, reference sensor (52) is mounted axially before the vane wheel (20) on which a mark support (58) is mounted, carrying marks (62) to which the reference sensor (52) responds and delivers counting pulses. Pulses from both sensos (48, 52) are applied to a comparator (70) which delivers an error signal when the pulse ratio does not correspond to the vane to mark ratio.