Integrated sensor for non-invasive monitoring of flow in pipes

A silicon chip fabricated with standard IC technology has been used to monitor air flow in a pipe in a non-invasive way through the pipe wall. Flow detection is based on the measurement of a temperature difference on the chip, which is heated with respect to the flow. The device is direction sensitive and has a zero output in the absence of flow. In the experiment the detection threshold for air flow is approximately 0.1 m/s.