The difference between precession vortex flowmeter and vortex flowmeter

In the field of industrial flow measurement, precession vortex flowmeters and vortex flowmeters are two common flowmeters, widely used in industries such as petroleum, chemical, and natural gas. Although both are based on the principle of fluid vibration, their operating principles, structural characteristics, and applicable scenarios differ significantly. This article will analyze the differences between the two from a technical perspective to help users more accurately select the right flowmeter.
1.Different working principles
A precession vortex flowmeter uses the precession effect of vortices (the center of the vortex spirals along its axis) created by fluid passing through spiral guide vanes to calculate flow rate by detecting the vortex frequency. Its internal structure typically includes a flow guide, a vortex generator, and a sensor.
A vortex flowmeter uses the Karman vortex street principle. When fluid flows through a bluff body (such as a triangular prism), two alternating vortex streets are generated behind it. Flow rate is estimated by detecting the vortex street frequency.
2.Applicable media and working conditions
Precession vortex flowmeter：
Particularly suitable for low-pressure gases (such as natural gas, compressed air, and coal gas), it has high sensitivity to low-velocity gases.
It has relatively low straight pipe requirements (3D in front and 1D in the back, where D is the pipe diameter), but it also has a high pressure drop.
Vortex flowmeter：
Liquid/Gas Universal: Widely used for steam (saturated/superheated), liquids (water, oil, etc.), and gases (air, gas, etc.), offering a wider range of adaptability.
Weak vibration resistance, not suitable for high-vibration environments.
Requires a long straight pipe section (typically 10D in front and 5D in the back) to ensure accuracy and minimize pressure drop.
3.Accuracy and range
Precession vortex flowmeters offer high accuracy at low flow rates, but their turndown ratio is relatively narrow.
Vortex flowmeters offer a wider turndown ratio and more stable measurements at medium and high flow rates, but may experience reduced accuracy at low flow rates.

Precession vortex flowmeters excel in natural gas metering, while vortex flowmeters are more suitable for measuring steam or large liquid flows. Users should make a comprehensive selection based on the media characteristics, flow range, and installation environment.