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Design and Fabrication of a MEMS Flow Sensor and Its Application in Precise Liquid Dispensing
State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, China
* Author to whom correspondence should be addressed.
Received: 17 April 2009; in revised form: 4 May 2009 / Accepted: 13 May 2009 / Published: 2 June 2009
Abstract: A high speed MEMS flow sensor to enhance the reliability and accuracy of a liquid dispensing system is proposed. Benefitting from the sensor information feedback, the system can self-adjust the open time of the solenoid valve to accurately dispense desired volumes of reagent without any pre-calibration. First, an integrated high-speed liquid flow sensor based on the measurement of the pressure difference across a flow channel is presented. Dimensions of the micro-flow channel and two pressure sensors have been appropriately designed to meet the static and dynamic requirements of the liquid dispensing system. Experiments results show that the full scale (FS) flow measurement ranges up to 80 μL/s, with a nonlinearity better than 0.51% FS. Secondly, a novel closed-loop control strategy is proposed to calculate the valve open time in each dispensing cycle, which makes the system immune to liquid viscosity, pressure fluctuation, and other sources of error. Finally, dispensing results show that the system can achieve better dispensing performance, and the coefficient of variance (CV) for liquid dispensing is below 3% at 1 μL and below 4% at 100 nL.
Keywords: flow sensor; MEMS; liquid dispensing
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MDPI and ACS Style
Liu, Y.; Chen, L.; Sun, L. Design and Fabrication of a MEMS Flow Sensor and Its Application in Precise Liquid Dispensing. Sensors 2009, 9, 4138-4150.
Liu Y, Chen L, Sun L. Design and Fabrication of a MEMS Flow Sensor and Its Application in Precise Liquid Dispensing. Sensors. 2009; 9(6):4138-4150.
Liu, Yaxin; Chen, Liguo; Sun, Lining. 2009. "Design and Fabrication of a MEMS Flow Sensor and Its Application in Precise Liquid Dispensing." Sensors 9, no. 6: 4138-4150.