Automated high-temperature liquid level measurement system using a dynamic tube pressure technique

Abstract

Abstract An in-house manufactured liquid level measurement system based on dynamic tube pressure measurements was established for high-temperature corrosive molten salts. The accuracy and precision of the present technique depend on the furnace temperature, initial base tube pressure, and tube speed. Whereas the initial base tube pressure did not influence the performance of the measurements significantly, a set value of the critical pressure level for the detection of the liquid surface was an important factor, especially in case of the higher temperature experiments. Within a temperature range of 773–1073 K using KNO 3 , our technique could obtain a measurement error of less than ca. 0.05 mm in precision. The tube speed increased from 0.25 mm s −1 to 2.00 mm s −1 , resulting in a % departure of only 1.1%, 1.3%, and 1.9% at 773 K, 973 K, and 1073 K, respectively. The measurement of travel distance instead of measuring the liquid level is useful in terms of the calibration-free process monitoring. The gravimetric calibration method was also used to determine the total mass of the liquid, where the weight versus travel distance calibration curves showed an excellent linearity with R 2 = 0.9999 under all temperature conditions.