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A printed circuit board capacitive sensor for air bubble inside fluidic flow detection

Vu, Quoc T and Nguyen, Dac H and Pham, Quoc T and Nguyen, Dinh Duc and Chu, Duc Trinh (2014) A printed circuit board capacitive sensor for air bubble inside fluidic flow detection. Microsystem Technologies Journal, 21 (4). pp. 911-918. ISSN 0946-7076

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This paper presents a three-electrode capacitive fluidic sensor for detecting an air bubble inside a fluidic channel such as blood vessels, oil or medical liquid channels. The capacitor is designed and fabricated based on a printed circuit board (PCB). The electrodes are fabricated by using copper via structure through top to bottom surface of the PCB. A plastic pipe is layout through the capacitive sensor and perpendicular to the PCB surface. Capacitance of sensor changes when an air bubble inside fluidic flow cross the sensor. The capacitance change can be monitored by using a differential capacitive amplifier, a lock-in amplifier, filter and an NI acquisition card. Signal is processed and calculated on a computer. Air bubble inside the liquid flow are detected by monitor the unbalance signal between the three electrode potential voltages. Output voltage depends on the volume of the air bubble due to dielectric change between capacitor’s electrodes. Output voltage is up to 53 mV when an 2.28 mm3 air bubble crosses the sensing channel. Air bubble velocity can be estimated based on the output pulse signal. This proposed fluidic sensor can be used for void fraction detection in medical devices and systems; fluidic characterization; and water–gas, oil–water and oil–water–gas multiphase flows in petroleum technology. That structure also can apply to the micro-size for detecting in microfluidic to monitor and control changes in microfluidic channels

Item Type: Article
Subjects: Electronics and Communications > Electronics and Computer Engineering
ISI-indexed journals
Divisions: Faculty of Electronics and Telecommunications (FET)
Depositing User: Ms. Cam Le Tran Thi
Date Deposited: 03 Aug 2015 10:04
Last Modified: 09 Aug 2016 03:13

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