The miniaturised thermal flow sensor can be used both as a flow and differential-pressure sensor in direct operation or in the bypass. The basis of the SMD is a microtechnical silicon chip.
Areas of application for the MID flow sensor
The thermal flow sensor is suitable for all applications which require the measurement of low flow rates or pressure differences. Producing it as an SMD allows it to be integrated into an assembly automatically and as such it can be operated in direct operation or in by-pass mode. The maximum volume flow is 10ml/min. In principle the sensor can be integrated anywhere where the measurement of gases with low flow rates is necessary. Therefore, possible areas of application are, for example, in the automotive sector, household appliances, medical technology, environmental technology or measurement technology in industrial processes.
Operating principle of the thermal flow sensor
The most important element of the flow sensor is a silicon chip with a thin diaphragm containing temperature sensors and a heating element. The entire flow sensor measures a mere 12x10x6mm and only has a power consumption of up to 12mW. The measurement result is provided as an analogue signal in the form of an output voltage. To take a measurement the heating element distributes heat to the diaphragm which is then recorded and evaluated by the temperature sensors. If a gas flows around the sensor, the distribution of heat changes due to the movement of the medium. This allows the sensor to determine the direction and velocity of flow with a reaction time in the range of a few milliseconds.