The integration of pressure and position sensors into an intelligent control valve diagnostic system

A microprocessor based control valve diagnostic system was used to study the effects of a number of faults, that were deliberately introduced into a globe valve under controlled conditions, on the overall valve performance. Faults considered and reported in this paper are the gradual blockage of the actuator's vent hole and the increase in frictional forces due to a damaged valve packing. These faults were selected since they are common in petrochemical plants where control valves are exposed to harsh industrial environments. Similar tests were also carried out on control valves in an industrial plant, where real faults developed over a period of time. The results obtained from the experimental work and that from the industrial site were correlated and provided consistent results.