Liquid level measurement sensor for flow meter and industrial storage tank calibration

Abstract

The aim of this research contains two parts, firstly to develop accurate, simple and inexpensive liquid level measurement sensor for underground fuel storage tank and secondly the realization of a new calibration method for liquid flow meters. The level of the liquid can be detected with various methods such as Ultrasonic, Mechanical, Doppler, Capacitive, Optical, and Laser. Even though numbers of level sensors are available in the market the Dipstick is commonly used in industries to measure the liquid height. It is a time consuming manual method. Also standing-start-and-stop method and flying-start-and-finish method are used to calibrate flow meters. But those are expensive and complicated systems. Proposed capacitive liquid-level sensor measures the electrical capacitance between two electrodes immersed in a liquid and calculate the liquid level from the capacitance. It consists of two electrodes, inner electrode is surrounded by insulation material, and the outer electrode is aluminum pipe. The sensitivity, systematic error, random error and uncertainty of the sensor are better with tap water in the tank rather than petroleum products. The effectiveness of this proposed method is tested by a series of numerical and experimental tests. It reveals that an accuracy of the instrument is ±0.5cm and ±1cm with tap water and petroleum product respectively. The instrument has been validated against the calibrated dipstick and ultrasonic distance sensometer with liquid as the tap water. And also instrument has been validated by calibrated dipstick and pressure level measurement sensor with petroleum products.