Vortex flow meters measure fluid velocity using a principle of operation referred to as the von Kármán effect. It states that when flow passes by an obstruction in the flow path, vortices are generated in a repeating pattern.

In a Vortex flow meter, this obstruction is often referred to as a bluff body. The bluff body causes the process fluid to separate and form areas of alternating differential pressure known as vortices around the backside of the bluff body. In Pro-V® vortex flowmeters, a sensitive piezoelectric crystal sensor detects these vortices. The frequency at which the vortices are shed is directly proportional to the flow velocity. With the fluid velocity and area of the pipe known, a volumetric flow rate is calculated.

With optional integrated temperature and pressure sensors, Pro-V vortex flowmeters can provide a compensated mass flow rate. With the energy monitoring option, Pro-V meters can also provide a reliable (BTU) energy measurement of water, thermal oils, and steam.
 
Insertion style vortex flowmeters are a more economical option on large line sizes and can be installed under full process conditions (hot tapping).