Vortex Flowmeters

Vortex Flowmeters

Vortex flowmeters measure the volume flow of liquids, gases, and steam by exploiting the predictable vortex shedding that occurs downstream of a bluff body. They are widely used in utilities and process services, especially where steam and compressed gas measurement is needed with good long-term stability and moderate installation complexity. Modern multivariable vortex meters extend capability to mass flow by integrating temperature sensing and onboard flow computation.

In the measuring tube, a bluff body generates alternating vortices as flow velocity exceeds a threshold. The shedding frequency is proportional to mean flow velocity and therefore to volumetric flow, and the alternating pressure field can be detected (for example, via a capacitive sensor) and converted into a linear digital signal.

Benefits include broad suitability across liquids, gases, and steam, and performance that is largely unaffected by changes in pressure, density, temperature, and viscosity in many practical ranges. High long-term stability (no zero-point drift and a lifetime K-factor), strong turndown for gas/steam and liquids, and wide operating temperature capability support utility metering in harsh environments.

Typical applications include saturated and superheated steam measurement for energy efficiency and cost allocation, compressed air and nitrogen distribution, carbon dioxide and flue gas monitoring, and metering of condensate, boiler feedwater, solvents, and heat-transfer oils. Advanced offerings include steam quality monitoring with alarming for wet steam and suitability for safety-instrumented applications up to SIL 2 and SIL 3 with independent certification to IEC 61508.

Specification focuses on maintaining appropriate flow conditions: sufficient Reynolds number, stable velocity profile, and adequate straight-run or conditioning to reduce asymmetry and vibration sensitivity. Very low-flow operation can be limited by the minimum shedding threshold, so line size and turndown expectations should be aligned early. For steam services, compensation strategy (temperature/pressure) and wet-steam risk assessment often dominate the overall uncertainty and the business case for additional diagnostics.

George E. Booth Co., an exclusive authorized representative of sales and service for Endress+Hauser.