The RNG Series meter is an insertion-style vortex shedding flow meter designed to offer high accuracy measurements over an extremely large flow range. The meters have no moving parts and are virtually maintenance-free. The RNG Series is suitable for most gas types, including air, natural gas, digester gas and biogas applications. All meters in this series are loop-powered devices with standard HART® communications for ease of field
programming and system integration.

An everyday example of a vortex shedding phenomenon is a flag waving in the breeze: the flag waves due to the vortices shed by air moving across the flagpole. Within the flow meter, as flowing gas moves across the tiny strut or “bluff bar”, vortices are also shed but on a smaller scale. The meter transmits an ultrasonic beam through the vortex pattern downstream of the strut. As vortices are shed, the carrier wave of the ultrasonic signal is modified. This change in the carrier wave is measurable and moves in proportion to the number of vortices shed. Digital processing enables the vortices to be counted, and this
value is converted into a velocity. Software converts velocity into a volumetric flow rate, in units of measure selected by the operator. Racine Vortex flow meters utilize the smallest strut in the industry, which allows for high sensitivity; superior performance at very low flow rates; large turndown ratios; and low pressure drop. Through the use of an internal RTD and an external optional), the flow meter software will compensate for changes in pressure and temperature, to achieve an accurate mass flow measurement.

Racine vortex offers a sophisticated software program to aid in the flow meter selection process. The program accounts for system pressure and temperature, as well as media density, viscosity and specific gravity. Select from a complete list of Metric
and English engineering units, using default or customized reference standards for pressure and temperature.