Pitot tubes
Air velocity measurement based on pressure difference and thermal
Air velocity measurement is based on three measurement principles: pressure difference, thermal and wind velocity. The best known is a pitot tube measurement where a pressure difference is created by air flow. Another commonly used measurement principle is a hot wire measurement. The third measurement principle is a vane anemometer.
Pitot tubes
The Pitot tube, in combination with a differential pressure meter, is an instrument for measuring air velocity and is mainly used in air ducts and pipes. By traversing a duct, the Pitot tube can also be used to determine the air volume.
Pitot tubes can be used for measuring flow rates. The volume flow rate is then equal to the velocity times the cross-sectional area of the duct being measured. With the Pitot tube (also called Prandtl tube), the velocity pressure is determined from the difference between the total pressure, measured at the front of the Pitot tube, and the static pressure, measured at the side of the Pitot tube.
The Pitot tube is widely applicable, at low and high temperatures and for speeds from 2 m/s to 180 m/s. There are various types available such as the S pitot tube which is suitable for contaminated air. These pitot tubes are also available with integrated temperature measurement.