Vane air flowmeter? The air flowmeter has simple structure and high reliability. However, the intake resistance is large, the reaction is slow and the volume is large.

Carmen vortex street air flowmeter: refers to two rows of vortex street hot-wire air flowmeters with opposite rotation directions alternately appearing downstream of cylindrical or triangular objects placed in fluid?

Hot-wire air flowmeter: This flowmeter adopts an isothermal hot wire, as shown in figure 1. RH, RK, RA and RB form the four arms of the Wheston Bridge. Hot wire RH (generally platinum wire) and temperature compensation resistor RK (cold wire) are placed in the channel to be measured, so that the temperature difference between RH and airflow is maintained at a level (generally100&:ordm; C or150&; Ordmc). When the airflow increases, the cooling resistance of RH changes due to the acceleration of heat dissipation, and the bridge loses balance. At this time, the integrated circuit will increase the bridge voltage to restore the bridge balance, usually taking the voltage drop on RA as the measurement signal.

Hot film air flowmeter: The principle of this sensor is the same as that of the hot wire sensor, except that the hot wire is made into a sheet when it is manufactured.