The coolant decides whether Picomag belongs in the loop
Image: Endress+Hauser
Picomag measures flow electromagnetically, so its liquid has to be electrically conductive. That condition puts a firm boundary around Mouser’s proposal to use the Endress+Hauser instrument in cooling circuits.
A water-based secondary circuit may suit the measuring principle. An electrically insulating fluid used for direct immersion presents a different proposition. The cooling application alone says remarkably little about whether the instrument will work; the fluid chemistry settles that question.
Mouser is now stocking the Picomag range, which combines volume flow, temperature and conductivity measurements in one housing. That last measurement gives the controls system something useful beyond a flow value. A change in conductivity could help identify a departure from the expected coolant condition, provided the system has a baseline against which to interpret it. Temperature, formulation and treatment all affect what that reading means.
The instrument’s flow accuracy also deserves attention when choosing its size. Endress+Hauser specifies a maximum error of ±0.8% of reading plus ±0.1% of full scale. At one tenth of full scale, those terms amount to ±1.8% of the reading. The fixed full-scale contribution becomes increasingly significant as flow falls, which makes an oversized meter less attractive when low-flow detection is an important operating condition.
Picomag is available in sizes from DN15 to DN50. Across the family, the published range reaches 750 litres per minute, with a maximum process pressure of 16 bar. Normal medium temperature is −10°C to +70°C; excursions to +85°C are permitted for an hour, with at least four hours before repetition.
Integration is fairly straightforward: IO-Link connects the instrument to the controls system, while Bluetooth and the SmartBlue app provide local access for commissioning. Empty-pipe detection adds another diagnostic alongside the three measured variables.
The compact housing is appealing where a cooling skid already has very little spare space. Its greater advantage is the opportunity to interrogate a flow problem with temperature and conductivity available at the same point. That becomes useful only when the fluid is compatible and the selected measuring range still resolves the operating conditions that matter.
