Non metallic wear rings

[davie1980]

I've been reading an article on the advantages of non-metallic wear rings online, in a 3 part article called "the power of wear rings."

It makes a compelling case. The removal of traditional metal wear rings, means reduction of damage from impact between the impeller and casing, which means you can reduce the clearance distances, which in turn dampens vibration, reducing maintenance costs and improves seal/bearing life. It also improved shaft stiffness and increases efficiency among other appealing advantages.

I checked and all of the casing and impeller wear rings, which we use on our centrifugal pumps, are indeed metallic.

So I decided to investigate further. The artical I read, sold the idea like an infomercial, so I hunted the internet for some corroborating evidence.

The only thing I could find was a company that sells a polymer wear ring. I joked to myself "I bet the guy that wrote that article works for them."

I decided to go back and re-read the article and this time found a better presented pdf version and lo and behold, in the 'about the author' segment, he works for that company.

So basically what I'm here to ask is, does anyone have any experience of working with these products or have any source of information on them other than this guys long winded advertisment, trying to pass itself off as a research paper on improved pump efficiency.

It certainly sounds reasonable enough, what he's trying to say to a simple mechy like me, but are the benefits real? Do they justify the expense of the maintenance for replacement parts?

By all means go have a read through the article, it's easily found through google.
Any feedback would be appreciated.

 

[Artisi]

Well it must be true, it was on the internet and, would a company representative lie.


It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[ashtree]

Whilst it may be that this guy is actually a prophet preaching from the wilderness and the rest of us are non believers there is something about the internet that often lets you know where the truth is.
If there is one bloke saying x and everyone else is saying y then there is a fair chance that the guy is not a prophet even if what he says seems fair enough.
At the same time we should never be totally closed to new or alternate views. Isn't that what happened to the dinosaurs.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

 

[JJPellin]

We use at least four different compounds of non-metallic wear rings and bushings in pumps. We probably have 30 or 40 pumps that have been converted to non-metallics. We purchase these materials from at least four different companies that I can think of. We have installed these in multi-stage pumps that were prone to catastrophic failure when operated at too low a flow rate. We use them in vertical pumps in pits where dry running could occur. We have not really focused on the efficiency benefit and have not attempted to quantify the savings. I think that non-metallics are a very good choice for boiler feed water and oily water sewer applications (if abrasives are not a concern). We have a big Naphtha charge pump in the shop now that had polymer wear rings (axial split, API, 8 stages, 800 HP). We believe that the pump was run dry. The wear rings and bushings are all wrecked, but there is no damage to the impellers or the casing. If this pump had metal wear rings and bushings, I would have expected to find the case warped and in need of milling and line-boring. In that regard, the non-metallic wear parts saved us a lot of repair time and cost.

Johnny Pellin

 

[EdStainless]

I have built small pumps that used alloy cast iron housings and PPS impellers, they worked very well.

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P.E. Metallurgy, Plymouth Tube