A Micromachined, Membrane Based, Thermoelectric Flow Sensor for 2-Dimensional Measurement with High Angular Resolution

This paper introduces a novel membrane based, thermoelectric flow sensor for measuring flow velocity and angle in a plane. With a size of 2 mm in square it is much smaller than comparable sensors; nevertheless it reaches an angular resolution of one degree. It is fabricated in a surface micromachining process and consists of a heater and four thermopiles, embedded in a SiN membrane. The sensor was invented to measure air flow distribution in cooled storage rooms for apples in order to enable a real-time control of the fans to reduce their power consumption. Due to the SiN membrane it's furthermore possible to operate the sensor with various gases and liquids.