In the early 1970s, I was part of a centrifugal pump inspection team whose goal was to increase pump reliability.  At the same time, we were converting many pumps from packing to mechanical seals.  We were also converting some pumps with single seals to tandem seals.  We were a busy group and I was on a very steep learning curve.

Even though I was new to pumps and seals (well, bearings, lubrication, — ok, everything!) our group leader made no bones about what he wanted and expected from our seal suppliers:  SEALS.  That was just about it.  He expected our suppliers to have lots of spare parts on hand for essentially immediate delivery.

Of course, we also wanted to be kept informed of the latest developments in the world of seals.  We wanted to see lab tests, technical papers, advances in materials such as perfluoroelastomer and silicon carbide, etc.  Finite element analysis was beginning to be used to study seal design and performance.  This was an exciting time to be learning about mechanical seals.

In those days, we did our own failure analysis and we had plenty of failures to examine.  By our rules, Mean Time Between Repairs (MTBR) was only about a year (some would have called it 2 years or more).   Improvements in reliability through failure analysis was one of the main functions of the inspection group.  We used failure analysis to point towards specific and general methods of improving reliability.  We did not want to be simply “parts changers”. 

We also did our own seal repairs, including lapping, and rebuilt our own seals.  Training was done by our group leader.  I actually heard him say, somewhat arrogantly, to a seal salesman:  “What can you teach me about seals?”  But then, he enjoyed challenging people – including our own group members.  We actually did go to a few outside, independent seals training courses and sometimes even asked a seal OEM for a detailed failure analysis report.  But, for the most part, we did not rely on the seal OEMs.

Of course, we had our own inventory of critical pump and seal parts in addition to the seal supplier’s inventory.  The relative proportions of these inventories were always a bone of contention.  I have to laugh when someone says that, long ago, inventory did not matter.  Of course inventory mattered – the “optimum” was simply a different amount than it is today.

We even had an equipment records system that used a computerized database (yes, even in the ‘70s!) of equipment, services and repairs.  Querying this database provided statistical evidence of problem pumps and problem components.  Yes, mechanical seals were the main component causing pump repairs.  In addition to the computer databases, we also had good old paper files for each pump which included the original specifications and datasheets, notes on repairs and, occasionally, a photograph but more often a sketch.

I realize that every process plant was not so well staffed, directed and equipped but mine was and I have greatly benefitted from that experience.

Fast forward some five decades and the relationship between seal supplier and end user is vastly different.  Most end users do not do failure analysis and do not rebuild their own seals.  They may not have their own equipment databases and failure records.  They even may not have an inventory of seal parts.  Instead, most end users seem to rely on their seal suppliers to provide not only goods but also services.

As a result of the changes in this relationship, it is the seal supplier who gains the experience and the knowledge that I received as an end user.  The seal supplier typically provides a technician or engineer, very nearly a contract employee, to his customer, the end user.  This person collects data, examines seal failures, makes recommendations (and gets to see the effect of those recommendations!) and builds up an equipment and failure database.  The loss of experience for the end user is definitely a gain in experience for the seal supplier.

So, what do you want from your seal supplier?