Abstract
Flow sensors are the key elements in most systems for monitoring and controlling fluid flows. With the introduction of MEMS thermal flow sensors, unprecedented performances, such as ultra wide measurement ranges, low power consumptions and extreme miniaturization, have been achieved, although several critical issues have still to be solved. In this work, a systematic approach to the design of integrated thermal flow sensors, with specification of resolution, dynamic range, power consumption and pressure insertion loss is proposed. All the critical components of the sensors, namely thermal microstructure, package and read-out interface are examined, showing their impact on the sensor performance and indicating effective optimization strategies. The proposed design procedures are supported by experiments performed using a recently developed test chip,including several different sensing structures and a flexible electronic interface.
Highlights
An accurate measurement of gas flow is required in many applications, including industrial processes control, internal combustion engines optimization, monitoring of gas distribution lines, Micromachines 2012, 3 control of ventilation and air-conditioning systems and monitoring of patient breathing
According to the operating principle, thermal flow sensors can be divided into three main categories, namely hot-wire sensors, calorimetric sensors and time-of-flight sensors
The heaters are deposited over thermally insulating membranes, anchored to the cavity edges through a series of arms
Summary
An accurate measurement of gas flow is required in many applications, including industrial processes control, internal combustion engines optimization, monitoring of gas distribution lines, Micromachines 2012, 3 control of ventilation and air-conditioning systems and monitoring of patient breathing. The wide majority of the proposed devices are based on a thermal principle. This is mainly due to their suitability to be integrated on silicon chips using standard microelectronic processes, making them ideal candidates for the fabrication of integrated smart sensors. According to the operating principle, thermal flow sensors can be divided into three main categories, namely hot-wire sensors, calorimetric sensors and time-of-flight sensors. Calorimetric sensors measures the difference between the downstream and upstream heat fluxes stemming from one or more heaters exposed to the flow. Time-of-flight sensors measure the time that elapses between a heat pulse applied to the heater and the pulse detection by a downstream temperature probe. Sensors based on a combination of multiple principles for extending the operating range have been proposed [7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
