Combined with deficiencies in the training of personnel, it can be argued that pump reliability has not made as much progress as it perhaps could. This view is supported by repeat failures of process pumps. It is evident that whenever random or repeated failures occur in process pumps, the true root causes of these events have not been uncovered. In many instances, tradition favors treating the symptoms or, just as inappropriately, doing nothing at all.
Tightened Specifications Often Inappropriate
A closer look at the issue of unidentified repeat failures shows another worrisome trend. Tradition-bound reliability engineers look at pre-existing specifications and decide to make the new specification tighter. The fallacy of simply tightening a specification is best shown in four case histories. Each deals with fluid machinery and illustrates that tighter specifications do not automatically translate into better and truly life extending specifications. Well-focused specifications increase safety, equipment reliability and bottom-line profits. Tight specifications may fall far short of reaching the goal.
Case 1 and high temperature pump lubrication
Many years ago, a Canadian consulting engineer was impressed by a well-designed API-style pump at a refinery in Trinidad. He fully understood the merits of pure oil mist lubrication which, in this instance, benefited a visbreaker heavy fuel oil pump that processed flammable hydrocarbons at 750 degrees F. For many years, the pump and its rolling element bearings ran safely, successfully, dependably, flawlessly and reliably. Later, in the early 1980s, the same reliability-focused machinery engineer learned more about pumps in pipestill bottoms service with fluid temperatures of 740° F at many U.S. oil refineries. For decades, dozens of these high temperature process pumps have been lubricated by pure oil mist, again, successfully, dependably and flawlessly.
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