Vortex flowmeter to measure liquid, gas or steam volume flow, standard condition volume flow or mass flow based on the principle of Karman vortex street, and as a flow transmitter application automation and
control systems.
Our vortex flow meter uses advanced differential technology, with isolation, shielding, filtering and other measures, we overcome the shock of similar products is poor, small- signal data disorders and other problems, and uses a unique sensor packaging technology and protective measures,ensure the reliability of the product.Each form has a whole sub- structure, according to the measurement of different
diameters, there are pipeline, two plug-in installation, to adapt to different installation environment.
Measuring Principle
Vortex Street Flow Indicator is to measure flow rate through using Karman vortex street principle. When inserting vertically a column into the measuring tube, fluid flows through both sides of column to naturally and alternately produce regular swir（l shown in the following figure），this swir is called Karman vortex street. When d/D=0.281, the releasing swirl is the most stable. （D is tube diameter）The releasing frequency of Karman vortex street is relating with fluid rate of flow and the width of the column.
Representing in the formula below:
f=St·v/d
f-releasing fquency of Karman vortex
St-coefficient（called Strouhal Number)
v-flow rate
d-column width
Strouhal number is an important coefficient of Vortex flow meter, in certained reynolds number range, Strouhal number is nearly constant. As the Dia at the right side, in the plain part of curve St=0.17, the releasing frequency is direct proportion to flow rate. From the measuring frequency f we can get flow rate v, and through v we get volume flow rate. FM11 Series Vortex flow meter is one kind of strain type of Vortex Street Flow Indicator, the swirl releasing frequency of the sensor is measured through detecting
the piezoelectric element inside of sensor(probe).
Application
The instrument can be widely used in large, medium and small variety of pipes and drainage, metering industrial recycling, waste water treatment, oil and chemical reagents as well as compressed air, saturated and superheated steam, gas and a variety of media traffic.
Technical parameters
| Fluid Measured | Saturated vapour, steam-gas, general gas, liquid (advoid multiphase flow) |
| Measuring Precision | Liquid: 1.0; gas: 1.5 |
| Repetitiveness | Liquid: 0.3%; gas: 0.5% |
| Measuring Range | Gas: 7m/s ～ 40m/s; Liquid: 0.7m/s ～ 7m/s |
| Working Pressure | Standard is 1.6Mpa, 2.5-4.0 Mpa, customized |
| Fluid Temperature | -40℃～ 250℃（normal type）；100℃～ 350℃ （high temperature type） |
| Housing Material | Stainless steel 304 |
| Output Signal | Pulse signal（three-wire system, low electrical level ≤ 1V, high electrical level ≥ 4V）；4-20mA；RS485 interface |
| Power Supply | 24VDC(or 12VDC)，lithium battery |
| Ambient temperature | -35℃～ 60℃（without LCD）；-5℃～ 60℃（with LCD） |
| Relative humidity | 5 ～ 95% |
| IP grade | IP65 |
| Electrical connection | M20×1.5 (With cable clamping nut assemblies) |
| Explosion proof type | Non-explosion proof, explosion proof optional |
