Working Principle of Vortex Flow Meter

Vortex flow meters use a principle called the Karman effect to measure liquids, gases and vapors. In fluid dynamics, a Karman vortex lane is a repeating pattern of rotating (swirling) vortices caused by a process known as vortex drift (shedding). As water (or any other liquid, gas or vapor) flows through an obstacle, the fluid separates and creates an alternating differential pressure called a vortex.

The flow velocity of the fluid and the vortex generation frequency are proportional to each other. Therefore, detecting the number or pulse of vortices makes it possible to measure flow. The main method of detection involves sensing the vortex vibration with a piezo sensor.

Vortex flow meter requires a well-developed and symmetrical flow velocity profile, free from any distortions or swirls to ensure good accuracy and repeatability. It is a standard practice to install it away from any source of turbulence. Common source of turbulence includes pumps, valves, changes in line direction (i.e. bends), changes in line size etc.