FB vortex flowmeter

A vortex flowmeter, also known as a Karman vortex flowmeter, is a volumetric flowmeter developed and produced based on the Karman vortex principle to measure the volumetric flow rate, standard condition volumetric flow rate, or mass flow rate of gases, vapors, or liquids. It is mainly used for flow measurement of industrial pipeline media fluids, such as gases, liquids, steam and other media. Its characteristics are small pressure loss, large range, high accuracy, and it is almost not affected by fluid density, pressure, temperature, viscosity and other parameters when measuring the volumetric flow rate of working conditions. It has high reliability and low maintenance.

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

f=St·v/d

Where:
F - Release frequency of Karman vortex street
St - Stroha number
V - average velocity on both sides of the vortex generator, m/s；
D - Column width

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

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

Basic Parameters