A hot platinum thin film anemometer

In this paper, a platinum thin film thermal flow sensor was presented. Design, fabrication process and thermal analysis were presented and discussed. Compared with traditional structure of four supporting beams, the present structure can provide high sensitivity and good strength because of the unique thermal and mechanical design. The sizes of the flow sensor chip are 571 μ m × 280 μ m × 0.25 μ m. The experimental results show that this flow sensor is capable of measuring the flow rate and has a good linearity in the flowmeter capacity (0.1 to1 m³/h) and also the linearity of the sensor is less influenced by the resistance of the sensor and flow orientation at a constant input voltage. The sensors subjected to different voltage input have been tested and the results show that the sensor has better performance under 3V voltage input. It demonstrates that the micro-machined flow sensor has great potential to be used in detecting flow rates within 0.1 to1 m³/h.