Liq. flowmeter using light beam and sensor - has rotating disc with holes which modulate IR light beam converted into pulses received by sensing phototransistor

摘要

The flowmeter has a case with an inlet and outlet, in which a measurement wheel is mounted. A device delivers a test value in accordance with the measurement wheel angular velocity. The measurement wheel (18) has a disc (32) normal to the wheel shaft and having evenly distributed holes. A light source (38) is mounted in the housing on one side of the disc, and a sensor (42) on its other side, converting light into electric pulses. The holes are transparent for the light, but the rest of the disc is not. The light source (38) is typically an infra-red diode, and the sensor (42) is a phototransistor.