The vortex flowmeter, also known as the Kármán vortex flowmeter, is a volumetric flowmeter that measures the volumetric flow rate of gas, vapor or liquid, the volume flow rate or the mass flow rate of the standard condition according to the principle of the Carmen vortex street. It is mainly used for the flow measurement of industrial pipeline medium fluids, such as gas, liquid, steam and other media, which is characterized by small pressure loss, large range and high precision, and is almost not affected by fluid density, pressure, temperature, viscosity and other parameters when measuring the volume flow under working conditions, with high reliability and small maintenance.

Measuring principle
The vortex flowmeter uses the Carmen vortex principle for flow measurement. When a column is inserted vertically into the measuring tube, the fluid passes through both sides of the column and naturally alternates regular vortices (as shown in the figure below), and this column of vortices is called a Kármán vortex street. At d/D=0.281, the released vortex is the most stable (D is the pipe diameter. The release frequency of the Kármán vortex is related to the velocity of the fluid and the width of the column, which can be expressed by the following formula:

f=St·v/d

In the equation:
f – the release frequency of the Karmen vortex street
St – Stroha number
v——Average flow velocity on both sides of the vortex generator, m/s;
d – width of the column

The Stroha number is an important coefficient of the vortex flowmeter, in a certain range of Reynolds number, the Stroha number is close to the constant, as shown in the figure below, in the straight part of the curve St=0.17, the vortex release frequency is proportional to the flow velocity, the detection frequency f can be obtained to obtain the flow velocity v, and the volume flow rate is obtained from v. The vortex flowmeter is a stress-type vortex flowmeter in which the vortex release frequency of the sensor is detected by detecting the piezoelectric element inside the sensor (probe).

Product Applications
This instrument can be widely used in large, medium and small pipelines for water supply and drainage, industrial circulation, sewage treatment, oil and chemical reagents, compressed air, saturated and superheated steam, natural gas and various media flow measurement.

Basic parameters

Measure fluids	Saturated steam, superheated steam, general gases, liquids (avoid multiphase flow)
Measurement accuracy	Liquid: Class 1.0; Gas class 1.5
Repetition	Liquid: 0.3%; Gas 0.5%
Measuring range	Gas: 7m/s ～ 40m/s; Liquid: 0.7m/s ～ 7m/s
Work pressure	The standard is 1.6MPa, 2.5 ~ 4.0MPa (Customizable)
Fluid temperature	-40℃～ 250℃ (Ordinary type)；100℃～ 350℃ (High temperature type)
Body material	SUS304
Output signal	Pulse signal (three-wire, low≤ 1V, high≥4V); 4 ～ 20mA; RS485 interface
Power	24VDC (or 12VDC), lithium battery
Ambient temperature	-35℃～ 60℃（No LCD）；-5℃～ 60℃（With LCD）
Relative humidity	5 ～ 95%
Ingress protection	IP65
Electrical interfaces	M20×1.5 (With cable clamping female assembly)
Explosion-proof type	Non-explosion-proof, flameproof (optional)