HART air/gas flowmeter

The FlexMasster ST98 flowmeter series from Fluid Components International is now compatible with the HART communication protocol for use in large-scale process and plant automation systems.

With an advanced thermal mass sensing element, the ST98 flowmeter features high accuracy to ±1% of reading, and ±0.5% of full scale. The ST98 also offers repeatability to ±0.5% of reading. The inline style ST98 features a flow range from 0.01 to 3140 Nm³/h in air at standard conditions for 21.2 °C and 0 °C, typical for most gases. The ST98 offers low-flow sensitivity yet is able to operate from 10:1 to 100:1 turndown ratio and is field adjustable within the calibrated range.

It is suitable for service in numerous process gases, hydrocarbon mixed or dirty gases, biogases including methane, and plant compressed air and HVAC systems, including a wide range of industries such as chemical, energy production, food/beverage, oil and gas, pharmaceutical, pulp and paper, steel, and wastewater treatment.

Two matched platinum precision resistance temperature detectors (RTDs) comprise the ST98’s thermal mass sensing element. One RTD is heated relative to the reference RTD, and the temperature difference between the two is related to the process gas mass flow rate.

The ST98’s transmitter converts the differential temperature to a standard 4-20 mA output signal that has been linearised during the FCI factory calibration. The ST98’s transmitter is housed in either a NEMA Type 4, Type 4X (IP66) enclosure or an explosion-proof enclosure and can be integrally mounted to the flow element or remotely mounted up to 130 m away.