Vortex flow meters are a well established flow technology and for liquid, steam and gas applications they can offer an accurate and cost-effective metering solution.
A vertical flow restriction, known as a ‘bluff body’ is fitted inside the flow meter bore and as flow passes by this bluff body vortices are generated alternately on each side, similar to the rippling effect of a flag blowing in the breeze. Sensors within the flowmeter body count the vortices as they are generated. There is a direct relationship between volumetric flow and the number of vortices generated and head-mounted electronics converts the signals received from the sensors to display instantaneous flow rate and totals.
Whilst Vortex flow meters can, and are, used to meter all kinds of low viscosity liquids and gases probably the majority of applications involve steam measurement. The Endress + Hauser Vortex meter offered by Flowquip can even be supplied with an integral temperature sensor to enable the mass flow measurement of dry saturated steam. In the case of superheated steam a separate pressure transmitter together with the Contrec Gas and Steam Flow Computer can be used to meter mass flow.
Care should be taken when selecting a Vortex flow meter for metering liquids. As a general rule only liquids with a maximum viscosity of 5 cP should be considered. This is because vortices cannot be reliably generated in viscous liquids. There are many alternative flow technologies for liquid measurement so it may be prudent to confine vortex flow meters to the measurement of gases and steam.
Flowquip Vortex Shedding Flowmeters are available for 15mm to 300mm pipelines in flanged or wafer configuration. They offer the advantage of a wide flow range with the added benefit of no moving parts. An integral, or remote mounted, LCD indicates flow rate and total and provides options of a pulse and/or 4-20mA output. Typical flow turndown is 30:1 with measuring errors of 1 to 2%. Hazardous Area applications can also be handled as ATEX Approval is a standard option. Each flowmeter is individually calibrated and despatched with its own calibration certificate.