Investigation on Unhealthy Control Valve Characteristic using Acoustic Emission Technique

Control valve, commonly known as final control element, is the vital element of any process plant and its performance must be monitored regularly to detect any problem occurring in advance. The detection of defects in control valve at early stages is crucial for plant operator to prevent unexpected shutdown. Thus, an effective maintenance plan could be set up to minimize the costly downtime. This project concentrates on investigating the unhealthy control valves characteristics based on the Acoustic Emission (AE) signal emitted from the fault. From that, the description about the AE characteristic of unhealthy control valve is made and it can be applied for further application in online monitoring system.
The project is divided into three stages. The first stage concentrates on preliminary research on the AE signal characteristics and its application on fault monitoring system. The second stage continues with the data saving process, where an experiment test rig is improved to serve the purpose of experiment activities and AE signal capturing. The experiment foundation basically includes a simple prototype of a process control loop accompany with a signal processing system where an AE sensor is implemented. At the end, the final stage of this project concentrates on processing the recorded AE signal by performing the signal analysis in frequency domain, using Fast Fourier Transform (FFT) and statistical analysis methods. Eventually, conclusions will be made up to summarize the AE signal characteristic of the unhealthy valve.