Measurement of Conductivity and Liquid Fill in Partially Filled Pipe Using Capacitive-Coupled Noncontact Probe

Autor: Tejaswini Kantamani, V. Jagadeesh Kumar, Boby George
Rok vydání: 2020
Předmět:
Zdroj: IEEE Sensors Letters. 4:1-4
ISSN: 2475-1472
DOI: 10.1109/lsens.2020.3018780
Popis: A noncontact capacitively coupled probe for the measurement of the liquid fill level and conductivity in a partially filled but horizontally kept pipe is presented. Capacitively coupled electrodes are used for conductivity measurements, but the error is high when the tube is partially filled with liquid. In this letter, we propose to use the values of the coupling capacitors formed between the liquid column and conductive electrodes to calculate the fill level and estimate the conductivity of water in the pipe. The resistance of the liquid column is determined using a recently reported autobalancing signal conditioning circuit. The circuit is designed to provide voltage directly proportional to the resistance of the water column. Voltages at the relevant nodes of the circuit are tapped to compute the equivalent coupling capacitance values. The resistance of the liquid column along with fill level determined through coupling capacitance values helps in measuring the conductivity of water flowing through the pipe. A worst-case error of ±0.9% was obtained in measuring the conductivity, and a worst-case error less than 0.52% was observed in the water fill level measurement from a prototype noncontact water conductivity measurement probe for a partially filled pipe that has been developed and tested.
Databáze: OpenAIRE