Measurement principle 
 The vortex flowmeter is the use of a Karman vortex street principle of flow measurement. Vertically into a cylindrical object in the measuring tube, the fluid on both sides of the columnar objects naturally alternately produce regular swirl (shown below), this whirlpool column known as a Karman vortex street. The release of the vortex is most stable when d / D = 0.281. (D is the diameter of the pipe.) The release of Karman vortex street frequency and fluid flow can be expressed as: 
 The F = st? V / d where: 
 Release frequency of the F -------- Karman vortex street 
 St -------- coefficient 
 V --------- flow 
 d --------- width of the columnar objects 
 Strouhal coefficient is an important factor of the vortex flowmeter, within a certain range of Reynolds numbers, the Strouhal number is nearly constant. As shown below, in the flat part of curves St = 0.17, whirlpool release frequency is proportional to flow rate, detection frequency f can be obtained flow velocity v The volume flow obtained by the v. 
 For measuring flow the vortex separation frequency and flow velocity changes from the impact of fluid density and viscosity. Partial pressure pulsation, accompanied by the swirl separation piezoelectric probe detected, and is converted into a whirlpool of frequency corresponding to the pulse signal detection circuit. Pulse signal can also be converted to the F / V and V / I 4-20mA standard current signal output. 
 XFV Series Vortex Flowmeter advantages 
 ◆ XFV Series Intelligent Vortex Flowmeter The biggest advantage of the vibration performance is particularly good, lunch and zero drift, high reliability 
 ◆ vibration resistance, especially 
 Vortex flowmeter for a long time a large number of waveform analysis and spectrum analysis. Singapore Airlines to design the best shape of the probe, wall thickness, height, diameter of the probe rod and a matching of the piezoelectric crystal, using advanced CNC lathes for processing, to ensure concentricity and surface finish and other technical parameters of processing. With the special process. Maximum overcome this common problem of the inherent self-oscillation frequency signal of vortex flowmeters. This is the unique advantages of SIA manufacturing vortex flowmeter technology. SIA company factory vortex flowmeter has excellent vibration resistance. 
 ◆ XFV Series Intelligent Vortex flowmeter sensor very versatile, allowing the sensors have good interchangeability. Use of advanced numerical control equipment processing the sensor body, and the whirlpool of sound body, to ensure the accuracy of processing, making the parts (especially the versatility of the whirlpool of sound body), which really do not due to replacement of parts affect the sensor repeatability and accuracy, which can produce strong and stable vortex signal. 
 ◆ structure is simple and solid, no moving parts, high reliability, easy maintenance role. 
 ◆ detection component does not contact with the media, stable performance, long service life. 
 The sensor detection probe and swirl to occur separately from the body in accordance with seals and high temperature piezoelectric crystal in the detection of the probe does not contact with the measured medium, so the the XFE vortex flowmeter organization is simple, versatile, stable and high. 
 ◆ pulse output proportional to flow, preferences or molded melon signal, zero drift, high accuracy, convenience and total