Karman Vortex Flowmeter

Today's introduction isKarman Vortex Flow Meter

This device is a vortex flowmeter, using a law theoretically proved by Theodore von Karman in 1912. In the presence of columnar obstructions (vortex generators) in the flowing fluid, alternating flow is generated downstream.
The flow velocity of the fluid is proportional to the vortex frequency. Therefore, the flow rate can be measured by detecting the number of eddy current pulses. The main detection method is to use piezoelectric elements to sense eddy current vibrations, but it is more reliable to use ultrasonic waves to detect eddy current vibrations.

Advantage:
・No mechanical moving parts
・Can detect liquids, gases and vapors
・Excellent chemical resistance due to the absence of electrodes
・Large range and high precision

Shortcoming:
・Since it restricts the flow path, pressure loss occurs
・Limescale and liquids containing solids can cause clogging
・Not suitable for high viscosity fluids
・Sensitive to pipeline vibration
・Requires a straight pipe

What is pressure loss?
For example, if a portion of the flow channel is restricted, the downstream pressure will decrease from the restricted area, which is called pressure loss. Pressure loss is a loss of energy, and not only does the downstream pressure decrease, but the flow and flow rate also decrease. When pressure loss occurs on the production line, the flow rate of circulating cooling water decreases, causing various quality and production problems.

Factors causing pressure loss:
1.Reduce the pipe diameter
2.Curved line
3.Install the on/off valve

source:KEYENCE

 

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