Economic flow measurement for low pressure gases solved using variable-area (VA) meter with supermagnet float
Influx Measurements has solved the design problem of achieving economic flow measurement for low pressure gases, typically met on methane or sour gas monitoring from digesters.
The Influx product is a stainless steel Flotrak VA meter, fitted with a PTFE float.
Supplied recently to FM Environmental of Newry, a 2 inch flanged Flotrak meter was calibrated over a range of 5-70m3/hr, for an available pressure of only 6mbar in the process gas monitored.
Encapsulated within a PTFE float, a light-weight 'supermagnet' signals the float position to a microprocessor based sensor module.
The 4-20mA output from this ATEX approved intrinsically safe sensor transmits the digester gas flow information to the process control system.
FM Environmental is a specialist in waste treatment, and this unit was supplied for a novel dissolved air flotation and anaerobic digester system used to treat a high BOD effluent from a brewery maltings factory.
The digester gas flow measurement provided by the Influx Flotrak is one of the many parameters monitored by the FM Environmental SCADA system, assessing the digester status and controlling the effluent feed.
Mark Towner, managing director of Influx Measurements, commented: "Previous designs of variable area flowmeter have not been able to achieve flow transmission output at such low operational pressures.The unique design features of the Influx Flotrak now allow the lower cost VA (variable area) flowmeter technology to be applied to biogas and digester gas flow applications."
