Vortex Flow Meters - Axiom-Northwest

RNG Series Insertion-Style Gas Flow MeterThe RNG Series meter is an insertion-style vortex shedding flow meter designed to offer high accuracy measurements over an extremely large flowrange. The meters have no moving parts and are virtually maintenance-free once installed. The RNG Series is suitable for most gas types, including air,natural gas and wet or “biogas” applications. All meters in this series are loop-powered devices with standard HART ® communications for ease of fieldprogramming and system integration.Operating PrincipleAn everyday example of a vortex shedding phenomenon is a flag wavingin the breeze: the flag waves due to the vortices shed by air movingacross the flagpole. Within the flow meter, as flowing gas moves acrossthe tiny strut or “bluff bar”, vortices are also shed but on a smaller scale.The meter transmits an ultrasonic beam through the vortex patterndownstream of the strut. As vortices are shed, the carrier wave of theultrasonic signal is modified. This change in the carrier wave ismeasurable and moves in proportion to the number of vortices shed.Digital processing enables the vortices to be counted, and this value isFLOWconverted into a velocity. Software converts velocity into a volumetricflow rate, in units of measure selected by the operator.Racine Vortex flow meters utilize the smallest strut in the industry, whichallows 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 pressure sensor(optional), the flow meter software will compensate for changes inpressure and temperature, to achieve an accurate mass flow measurement.Transmitting TransducerSmall StrutShed VorticesReceiving TransducerSpecificationsMeasured:Gas/AirVelocity Range:2 to 140 FPS (0.6 to 43 MPS)Operating Temperature: -20 °F to 300 °F (-28 °C to 150 °C)Ambient Temperature Limits: -20 °F to 155 °F (-28 °C to 68 °C)Operating Pressure: -5 to 250 PSIGAccuracy:1% of reading over dynamic range of meterRepeatability:0.5% of readingResponse Time:150 milliseconds maximumInput Power:15-24 VDCSignal Output:2-wire, 4-20 mA loopConstruction: Stainless steel wetted parts with Teflon ®transducers, NEMA 7 transmitter enclosureStandard:2" 150# ANSI FlangeOptional:2" 300# ANSI Flange2" MNPT CouplingDN 50 Metric FlangeCommunications:HART ® Protocol (Via PC or HART Modem)Certifications:CEOptional ATEX (EEx ib IIB T4) Zone 1, Group IIB, T4(Equiv. to N.A. Class I, Div 1, Groups C & D, T4)Options:2 line, 8 digit rate/totalizer displayInternal RTD temperature compensation formass flow measurement2 Tel: 262-639-6770