PFLOW: OEM MEMS mass air flow sensors for medical and process control applications
PEWATRON has released the new MEMS mass air flow sensor PFLOW which incorporates the latest MEMS and microelectronics innovations. The PFLOW sensor has a very high resistance towards clogging and pressure shock. Because of the innovative MEMS thermal isolation design does not require fragile thin membranes or surface cavities for thermal insulation. The sensor has a very high sensitivity at low flows and is thus perfectly suited for medical and advanced applications within the process industry.
The flow sensing die consists of two thermopiles symmetrically positioned up and downstream from a heater element which heats up the hot junctions. Each thermopile consists of 20 thermocouples in series to reveal the highest level of sensitivity. When a flow passes over the die, the thermopiles generates an output voltage proportional to the temperature gradient (asymmetric) between the hot and the cold junction due to the Seebeck effect. In case the medium is static (no flow), the temperature profile of both - up and downstream - is symmetric.
Five standard measurement ranges are offered from 0…10 SCCM to 0…2000 SCCM, as well as customer specific ranges between 10 and 2000 SCCM. Accuracy is better than +/-2.0% FS, and the temperature compensated analog output (0…50°C) is highly linear with flow. Analog voltage output is between 1 and 5 VDC, and the sensor is resistant to water condensation. Response time is very fast, and about 1-3 ms.
