Spectral analysis of internally leaking shut-down valves

摘要

We herein describe the results obtained from a set of experiments conducted on a shutdown valve, the objective of which was to identify the degree of internal leakage through the valve in its closed state. Leakage in a valve is not only a concern in terms of safety, but can also contribute to high maintenance costs and the loss of supply. Any improvements to the methods available for monitoring the condition to the valve may yield substantial cost savings and safer working conditions. All the experiments were conducted after causing damage to a valve and by subsequent monitoring of the vibrations caused by the resulting leak, using different types of instrumentation, including acoustic emission and dynamic pressure sensors. We carried out an analysis of the data obtained, in which our primary focus was the spectrum of frequencies obtained from each of the signals emitted. The methods we used deemed to be effective for the detection of leaks. The quantification of the leaks is a rather more complex matter that warrants further investigation, however. Further research is also suggested on the effect of external disturbances, the influence of the experimental parameters, and the applicability of analytical models.