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

2. Carmen vortex street air flowmeter

An instrument for determining air flow by detecting vortex frequency by optical or ultrasonic method takes advantage of the fact that two rows of vortices will be generated downstream when the airflow bypasses the cone, and the vortex frequency is in a functional relationship with the intake flow.

3. Optical Carmen vortex street air flowmeter

In the process of producing Carmen vortex, the air pressure on both sides of the vortex generator will change and act on the metal foil through the guide hole, thus making it vibrate. When the light of the LED shines on the vibrating metal foil, the reflected light on the metal foil received by the phototransistor is vortex modulated light, and its output will be demodulated to obtain a frequency signal representing the airflow.

4. Hot film air flowmeter

The flowmeter adopts isothermal hot wire. Instead of using platinum wire as hot wire, the hot wire resistor, compensation resistor and bridge resistor are made on the same ceramic substrate by thick film process.

Pay attention to the use of air flowmeter.

Pay attention to the correct installation of flowmeter, try to meet the requirements of straight pipe section of flowmeter, and try to install it horizontally. Pay attention to the inner diameter of flowmeter corresponding to the inner diameter of pipeline, tighten all flange bolts, and pay attention to the correct wiring of instrument. If in the open air, take rain and sun protection measures to protect the compressed air flowmeter.

Not every air flowmeter is installed in a place with strong vibration. However, the air flow meters installed in compressor room and blower room must consider the vibration problem. This kind of vibration mainly comes from compressors and blowers, and the vibration of the machine can be transmitted to far places through air pipes or air pipes.