Austin, TX— Emerson Process Management reports it reduced the number of valves removed for service at a Dow Corning plant after implementing its valve diagnostic services to predict impending problems and initiate efficient repairs. Emerson has a three-year contract with Dow Corning for control valve monitoring services at its plant in Barry, South Wales, Australia.

The plant is Dow Corning's largest global manufacturing facility for silicon-based products. Continuity of production is vital and, to ensure reliability, Dow Corning regularly dismantled and repaired up to 60% of the plant's control valves as part of its scheduled maintenance program. This was proving to be expensive and time-consuming.

By applying advanced diagnostic tools in Emerson's PlantWeb architecture, such as AMS Suite: Intelligent Device Manager and Flowscanning valve diagnostic services, to each control valve, Emerson's service personnel could check valve performance. And, by servicing only those valves identified as faulty, Dow Corning has been able to increase reliability and reduce maintenance costs.

For example, during a recent plant shutdown, a total of 191 valves were scanned. While traditional practice is to fully service up to 60% of valves in the plant, the Flowscanning service verified that only 51 valves required further investigation and, of these, just 16 valves were identified as needing a full service in the workshop.

"Around a third of the valves that were scanned using Emerson diagnostics had an issue. Some of these were minor while others were more significant," says Roy Phillips, Dow Corning's electrical control engineer. "If we had stroke checked these valves using a 4-20 mA source in the traditional way, it's likely that only half of the IP issues and a quarter of the positioner faults would have been identified. Significantly, we estimate that only two of the valve failures would have been picked up."

Because a reduced number of valves require full service, the demands on maintenance resources are significantly reduced. Flowscanning detects many minor faults that would have previously passed unnoticed, giving highly accurate results and significantly improving plant reliability.