The Hontzsch vortex effect flowmeter is one of the rare instruments that can measure gases with suspended particles. This metering instrument offers a turndown ratio of 1:160, which is remarkably high.
The Hontzsch vortex effect flow meter works on the principle of whirlwinds- the Karman effect. The stream of gas enters the restricted passage, and then splits into small whirlpools or vortexes to avoid the obstruction. These whirlpools are variable pressure zones and the rate of generation of these vortexes is directly proportional to the speed of the fluid.