Fluid flowmeter for gases and liquids - has a heated thermistor sensor connected to differential amplifier measuring temp. difference proportional to flow rate

摘要

The flowmeter utilises a semiconductor body (1) disposed in the gas or liquid. One end of the semiconductor body is heated by an electric resistance wire (3) such that a temperature difference and thereby a voltage difference is realised between the ends of the semiconductor body. The temperature difference, and thereby the voltage difference, varies inversely with the flow rate and is utilised for determining it. This is effected with the assistance of an amplifier across input terminals of which the semi-conductor body is coupled and on whose output a signal representing the flow rate appears. Pref. the semiconductor body is a thermistor.