Differential pressure sensor

Highly-sensitive differential pressure sensors on the basis of thermal flow sensors

Among the physical variables temperature has a special significance because almost every energy conversion is associated with a heat flux that influences the temperature of a system under consideration. Thanks to our many years of experience in the area of thermal sensors in MEMS technology, we are an ideal partner for sensor solutions for measuring differential pressures.

Traditional differential pressure sensors measure the pressure-dependent deflection of a thin membrane with piezo-resistive or capacitive processes. For the average pressure range (3 kPa - 6 MPa full scale) silicon sensors with a thin silicon membrane and diffused piezo-resistive resistors have gained extensive acceptance in the market. In the range under 3 kPa, for technological reasons these sensors can only be manufactured with complex production processes, because they must compensate temperature induced tensions of the sensor housing, or they are not available as a cost-effective solution. Consequently, precision-engineered membrane sensors, which however are large and relatively cost-intensive are still being used for this range today.

Differential pressure measurement on the basis of thermal flow sensors offers an alternative. With these sensors, a small, defined flow channel is attached between the two volumes with different pressure, through which a pressure-independent flow is built up. If the flow speed is measured with a sensitive thermal flow sensor, a signal is obtained that is proportional to the pressure. Between inlet and outlet the flow channel is routed over the sensitive membrane of the silicon chip. The flow channel is extended through a meander. The pressure sensitivity can be adjusted with the ratio of cross section to length of this meander. We develop and manufacture this sensor especially for your application and the desired parameters.

Contact


Dr. Sophie Billat
Hahn-Schickard,
Villingen-Schwenningen
Phone: +49 7721 943-242
Sophie.Billat@Hahn-Schickard.de
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