Robust Dynamical Method and Device for Detecting the Level of a Liquid Using Resistance Temperature Detectors

摘要

A method for indicating the level of a liquefied gas in a cryogenic tank having a resistance temperature detector (1). The controller applies a heating pulse to the detector and performs a single resistance measurement after the heating pulse. The overheating of the sensor and the time interval for the measurement are found in a separate set of test experiment. As a result, for temperature sensors with negative temperature coefficient, the resistance of the sensor in gas is below some unique characteristic value, which can be used like a threshold criterion to distinguish between the liquid and the gas in a wide temperature range. For sensors with positive temperature coefficient, the resistance of the sensor in gas is larger than some unique characteristic value, which can be used like a threshold criterion to distinguish between the liquid and the gas in a wide temperature range.