This column is a brief follow-up to my recent article, “Revisit Your Bidders’ Lists, Sooner Than Later” (July 25, 2020). While focusing specifically on pumping systems, some of the suggested strategies (and stated opinions) discussed here could have merit when it comes to upgrading other types of equipment in an industrial operation.
Of the numerous and generally costly process centrifugal pumps undergoing repair as you read these words, an estimated 90% have failed randomly before. That begs answers to some interesting questions: Could it be we don’t really know why so many of these pumps are failing? (After all, most large companies employ reliability professionals.) But why, then, are there still so many repeat failures? What do we really know and what don’t we know about failure causes?
We could ask a similar question of pump vendors. Do they know why many of their pumps are failing repeatedly or randomly? If they don’t know, that’s not good. If they do know and aren’t telling us, that also is not good. Pump vendors probably have to deal with countless issues, so we’ll just have to let them speak for themselves.
Click Here To Read The Referenced Article
“Revisit Your Bidders’ Lists, Sooner Than Later”
As to lubrication-related improvement initiatives, a well-known refinery contacted me last month (mid-July 2020) about a major failure involving oil rings on a 1,750-hp, 3,600- rpm pump-drive motor. This facility and more than one pump user have recently shown interest in obtaining bearing housings with oil spray as the preferred means of lube application. These end-users understand the limitations of cheap oil rings (also called slinger rings). Some existing pump bearing housings, and certainly a suitably redesigned bearing housing, could accommodate a gear pump that would take a small amount of oil from the oil sump, pressurize it, filter it, and inject this oil into the bearings.
Inquiry specifications requiring lube-application upgrades, though are often rejected by vendors producing things of lesser value, i.e., “stuff” that demands replacement or frequent repairs. Please remember that it does not have to be that way and that, for many hundred-thousands of pump drive ends (as opposed to fluid ends), there are reasonable alternatives. (Editor’s Note: Heinz summarized such alternatives in a recent (2020) book. The bottom line here is if you insist on something better than oil rings, a reasonable manufacturer will probably build it. As I advised in my previous article, try keeping the unreasonable ones off your bidders’ lists.TRR
Editor’s Note: Click Here To Download An Updated (May 2020) List Of Heinz Bloch’s 22 Books
ABOUT THE AUTHOR
Heinz Bloch’s long professional career included assignments as Exxon Chemical’s Regional Machinery Specialist for the United States. A recognized subject-matter-expert on plant equipment and failure avoidance, he is the author of numerous books and articles, and continues to present at technical conferences around the world. Bloch holds B.S. and M.S. degrees in Mechanical Engineering and is an ASME Life Fellow. These days, he’s based near Houston, TX. Email him at [email protected].
Tags: reliability, availability, maintenance, RAM, process pumps, pump bearings, pump-drive ends
