3D-Printed Calorimetric Flow Sensor
Gerjan Wolterink, Ameya Umrani, Martijn Schouten, Remco Sanders, Gijs Krijnen
Abstract
This work shows the development and char-acterization of a fully 3D-printed thermal mass flow sensor, based on regular and carbon-doped thermoplastic polyurethane (TPU). Using multi material fused deposition modelling (FDM) 3D-printing, the sensor is based on one heater element and two resistive thermal sensors (sensor -heater - sensor configuration). The transduction is based on the temperature dependent resistance of carbon doped polymers. Characterisation of the conductive TPU shows a positive thermal coefficient of resistance (TCR) ranging between 0.002 °C <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> to 0.024 °C <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , whereas the sensor shows a responsivity of 20 mV ml <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> min <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> in the pseudo linear range for flows below 3 mL min <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> while using a power of 1 W and a temperature up 58 °C.