Vortex Flowmeters

Vortex Flowmeters

Vortex Flowmeters measure volumetric flow by placing a bluff body in the flow stream to generate a repeating pattern of vortices downstream. As flow velocity increases, vortices alternately shed from either side of the bluff body; the shedding frequency is directly proportional to mean velocity and therefore to volumetric flow. The alternating pressure field is detected by the sensor and converted into a primary linear, digital signal.

The technology is widely used for liquids, gases, and steam because it delivers high long-term stability with minimal zero-point drift and a lifetime K-factor. Measurement is largely unaffected by changes in pressure, density, temperature, and viscosity, supporting consistent performance across normal operating swings. Typical turndown ranges from about 10:1 to 30:1 for gas/steam (and can reach up to about 40:1 for liquids), and the operating temperature window can extend from –200 to +400 °C (+450 °C on demand).

Vortex measurement is a common choice for utility accounting and energy optimization, especially in steam distribution where flow data supports boiler efficiency, heat-balance calculations, and leak or blowdown diagnostics. Advanced instruments can add application-specific functions such as monitoring steam dryness fraction and alarming on wet steam, as well as functional safety capability for flow monitoring architectures (e.g., SIL-rated implementations).

Typical applications include saturated and superheated steam lines, boiler and heat exchanger services, compressed air and process gas distribution, nitrogen and inert gas headers, and condensate or cooling-water service where Reynolds-number conditions remain within the specified operating range. Robust construction supports deployment in harsh environments and elevated-temperature utility corridors.

Selection considerations include required straight-run length, sensitivity to vibration and pulsation, and ensuring operating conditions remain above the vortex shedding threshold at minimum flow. Wet steam can bias volumetric flow unless quality is measured and compensated, so installation practice and diagnostic strategy matter in steam service. When engineered appropriately, vortex technology provides a rugged, repeatable flow solution for gases, liquids, and steam.

Forberg Smith, an exclusive authorized representative of sales and service for Endress+Hauser.