An ultra-compact electromagnetic flowmeter has been launched in the UK by European market leader in mass flow metering and control technology, Bronkhorst UK. Also available with an integral PID controller for flow control duties, this innovative Miniature-Mag series is suitable for measuring liquids with a low conductivity down to 5 microSiemens/cm, even as low as 0.1µS/cm for some applications, and for handling flow rates between 1 litre/hr and 3,000 l/hr. Intended mainly for smaller bore installations and capable of being used on pipework bends rather than just straight runs, it is available for internal pipe diameters between 1.5mm and 12mm and features empty meter detection for when there is insufficient flow. The very high speed of response makes it ideal for batching applications, a capability further enhanced by automatic overrun compensation.
Unlike standard magnetic flowmeters that require electrodes to be placed within the fluid path, often clogging up with sticky substances, Miniature-Mag sensors do not restrict the flow path, giving 100% full bore flow. This combination of features makes it ideal for many industrial and hygiene-critical applications, such as brewing, food processing, the dairy industry, agriculture, cosmetics and chemical dosing in water treatment processes. In addition, current changes in the pharmaceuticals sector from batch to continuous production, with consequent downsizing of plant and pipework, make it increasingly relevant to that industry.
Magnetic or electromagnetic flowmeters, commonly known as mag meters, are a common method of flow measurement, because they are easy to maintain, with no moving parts, and offer a high level of accuracy. Operation is based on Faradays law of magnetic induction, with the liquid acting as a conductor as it flows through the mag meter; this indicates a voltage proportional to the average flow velocity, which is picked up by sensing electrodes mounted in the pipework. Thus the fluid must be electrically conductive to induce measurable voltage and most standard magnetic flowmeters operate with fluids down to around 15-20 microSiemens/cm (measure of conductivity).
In contrast, Bronkhorsts ultra-compact magnetic flowmeter handles a minimum electrolytic conductivity of 5µS/cm as standard, with certain liquids measurable down to as low as 0.1µS/cm, or virtually non-conductive fluids. Economically priced, it also offers an accuracy of 0.2% of reading, with still greater precision available if required, high speed response and a totally unobstructed flow path. Such is its ultra-compact size, the Miniature-Mag does not need to be installed on a run of straight pipework, as with other mag meters or vortex and ultrasonic flowmeters, but can be tucked away on bends or other confined spaces.
With a footprint measuring just 100mm high x 100mm wide x 80mm deep and weighing just 800gms, the Miniature-Mag is housed in an IP67 rated dust- and water-tight housing, with the body available as standard in chemical-resistant PVDF or optional PTFE (Teflon), PVC or POM materials. There is a separate electronic display unit, with a 2 line, 16 character text readout, giving push button control of batch counting, pre-set alarms, menu selection and other functions.
The Miniature-Mag can also be specified as a flow controller, with an integral PID loop for control valve operation or direct pump control. Analogue, pulse, relay, RS232 and serial output connections are optional for interfacing with plant-wide control networks.
