Gas flowmeter modularizes transmitter functions

ST100 mass flowmeter from FCI creates upgradeable transmitter, future-proofs functionality.

05/02/2011


ST100 mass flowmeter from FCI creates upgradeable transmitter, future-proofs functionality.The new ST100 Series thermal mass flowmeter from Fluid Components International (FCI), combines high flow-sensing performance with a feature- and function-rich transmitter to deliver adaptability and value for gas flow measurement applications for today and tomorrow.

FCI says it developed the advanced ST100 Series flowmeters in response to discussions with a wide range of instrument, process, and plant engineers who wanted both more comprehensive measurement information as well as the flexibility to adapt to plant and process control technology they might deploy in the future. This new family is the result of those conversations.

In addition to its ability to measure, display, and transmit an extensive array of parameters, the company says it is the industry’s first thermal mass gas flow meter designed with a migration path to accommodate changing connectivity requirements. Whether the need is for conventional 4-20 mA with HART, frequency/pulse, alarm relays, or advanced digital bus communications such as Foundation fieldbus, Profibus, or Modbus, the new ST100 is the solution. Should a plant’s needs change over time or an upgrade prove desirable, the ST100 flowmeter adapts as necessary with a plug-in card replacement that can be changed by plant technicians in the field. This eliminates obsolescence as needs change.

FCI has also upgraded the ST100’s LCD display/readout, adding a graphical, multivariable, backlit LCD display to provide comprehensive information with continuous display of all process measurements and alarm status, plus the ability to interrogate for service diagnostics. Integral- and remote-display versions are available.

The unit measures a combination of gas mass flow rate, totalized flow, temperature, and pressure depending on the model family. It stores up to five unique calibration groups to accommodate broad flow ranges, differing mixtures of the same gas, multiple gases, and can obtain up to 1000:1 turndown.  An optional, patent-pending SpectraCal gas equivalency calibration method lets users select and switch between 10 common gases. Also standard is an on-board data logger with a removable 2 GB micro-SD memory card capable of storing 21 million readings.

With the ST100, FCI now claims the achievement of being the first thermal manufacturer to offer three different types of flow sensors, allowing users to choose the best approach for a given application. The FPC-style is a fast response type that features an integral, patent-pending flow conditioner and protective shroud optimized for compressed air and clean gas applications. The FP-style is a fast response, general purpose design with a protective shroud and is also the sensor used with FCI’s VeriCal in-situ calibration option. For applications with wet or dirty gases, or erratic flows, the unshrouded S-style facilitates easy cleaning and provides a smoothed response.

The ST100 Series includes two core model families: the ST and STP. The ST family measures both mass flow and temperature, and the STP family adds pressure, making it a triple-variable thermal flow meter, measuring flow, temperature, and pressure. Both families include single-point and dual-element models as configurations outfitted with FCI’s exclusive in-situ calibration option, VeriCal. 

Units can be calibrated to measure virtually any process gas, including wet gas, mixed gases, and dirty gases. The basic insertion style air/gas meter features a thermal flow sensing element that measures flow from 0.25 to 1,000 SFPS (0.07 NMPS to 305 NMPS) with accuracy of  ±0.75% of reading, ±0.5% of full scale.  

ST100 flowmeters are designed for applications with temperatures up to 850 °F (454 °C). The ST100 is agency approved for hazardous environments, including the entire instrument, the transmitter, and the enclosure. Instrument approvals (submitted and pending) include: FM and FMc Class 1, Division 1, Groups B, C, D, E, F, G;  ATEX and IECEx Zone 1, II 2 GD Ex d IIC T4. The enclosure is NEMA 4X/IP67 rated.

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Edited by Peter Welander, pwelander(at)cfemedia.com