Detecting the Blockage of the Sensing-lines of a Differential-Pressure Flow Sensor in a Dynamic Process Using Wavelet Transform Techniques

Abstract

The blockage of the sensing lines of a differential-pressure (DP) flow sensor is recognised as the main cause of malfunctions of many flow measurement systems in industry. In this paper, the blockage of the sensing lines under dynamic process conditions is investigated through wavelet transform analysis. The results obtained show that the blockage in a fast changing process is only detectable when the severity of blockage is over 90%. This outcome differs from that when the sensor operates under a slow varying process. The main reason for this difference lies in that a process with higher flow rate produces more noise energies in the output of the sensor than a process with lower flow rate