Fluid Components International ST51A Biogas Flow Meter

The ST51A Biogas Flow Meter, from Fluid Components International (FCI), is designed specifically for dirty, potentially hazardous biogas processes, making it suitable for engineers responsible for biogas production involving industrial organic waste and municipal wastewater treatment. It provides system operators with repeatable mass flow measurement to facilitate system control, log gas production data and provide mandated safety and environmental reporting information.

To survive in biogas processes, the meter comes with rugged 316 stainless steel body construction and Hastelloy-C22 thermal sensors. It features a no-moving-parts, non-clogging design, which eliminates the need for constant cleaning under wet, dirty biogas conditions. The meter comes with full global Division 1, Zone 1, Ex safety approvals.

The meter’s electronics are housed in a durable NEMA 4X, IP67 dust/water ingress protected and rugged, all-metal (aluminium or 316L stainless steel) enclosure with dual conduit ports in either NPT or M20 threading. The transmitter can be integrally mounted with the flow element (probe) or can be remote mounted for installation flexibility. The instrument comes standard with dual 4–20 mA, NAMUR NE43 compliant outputs and a 500 Hz pulse output.

The product adds digital communications via the HART 7 protocol. It provides plant staff with digital data on flow rate and temperature parameters, the instrument’s health, fault diagnostics and asset management info. It also features the capability to make field configuration changes if needed by using standard HART portable communicators.

The flow meter is available in multiple probe lengths for installation into pipe diameters from 263 to 610 mm. It is easily connected into the pipe via a 1/2″ or 3/4″ NPT compression fitting. Its insertion-style design requires only a simple, single point tap into the process piping that requires minimal technician time.

The flow meter utilises constant power thermal dispersion mass flow technology, which employs a slightly heated sensor that provides a subtle drying effect on condensating moisture to make it effective in moist biogas applications. Built-in temperature compensation circuitry provides correct readings under variable climate conditions — cold winters and hot summers.

The meter operates over a wide measurement range of 0.08 to 122 MPS with 100:1 turndown. The instrument’s standard accuracy is ±2% reading, ±0.5% full scale, with an optional configuration to provide higher accuracy to ±1% reading, ±0.5% full scale.