Cost-effective MEMS sensors give increased performance and reliability

Posifa Technologies offers its new PLF2000 series of liquid flow sensors. Created to replace mechanical turbine flow sensors, these cost-effective devices deliver precision and reliability, even in unstable pulsatile flow and low-flow conditions. Factory calibrated for water to a minimum 5% and typical 3% accuracy for volume calculation, the series' dual digital I2C and voltage output give high performance, flexibility, and scalability in a compact package.

The series features the company's third-generation thermal flow die, which employs a pair of thermopiles to identify changes in temperature gradient produced by mass flow. The result is an exceptional SNR and repeatability of 0.5% FS. The solid-state thermal isolation structure on the sensor die removes the requirement for a surface cavity or fragile membrane employed in competing technologies, enabling it to be placed right in the liquid flow path with minimum packaging for greater sensitivity. Also, the sensor die does not hinder the flow path, providing for minimal flow resistance and making it feasible to circulate liquid via gravity, a boiler, or a low-power pump. With no moving parts, the sensor does not become stuck, suffer mechanical breakdowns, or need disassembly for cleaning and maintenance.

Measuring flow rates up to 700ml/min (PLF2105) and 10l/min (PLF2135), the devices offer remarkably fast response times of 5ms typical and function over a +5C to +75C temperature range. The sensors comply with NSF/ANSI 61: Drinking Water System Components — Health Effects and can be employed safely in water and beverage appliances.