Non-Metallic Wear Rings 2

[Vikumar]

Hi All, Can anyone please list out few non-metallic materials used for Wear Rings in Submersible Multistage pumps (Water Applications)? I saw below post which was discussed on other thread, JJPellin can you please share the material list with comparison

JJPellin (Mechanical)20 Sep 16 12:12
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.

 

[EdStainless]

I have heard of about every possible engineered resin system out there.
The only ones that I have ever used were thermosets, often with both fiber and lubricant fillers (graphite, PTFE, or MoS2).
I know that Vespel is frequently used.
High temp thermo plastics will work also with material like PEEK and PPS.

1. Temperature suitability
2. Chemical compatibility (resin and fillers)
3. Mechanical characteristics (if you have abrasive wear you might need softer rings)

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P.E. Metallurgy, Plymouth Tube

 

[Vikumar]

Thanks EdStainless's, I'm looking for low cost material hardness similar to Polymer and preferably made from Injection molding process with controlled tolerance which helps to minimize or eliminate the machining operation

Coming to the Vespel CR-6100 is the material made from Injection molding and how about the cost comparing to PTFE or PFA

 

[EdStainless]

I had forgotten, pulled one out of a box of old parts and it is a Victrex compound, PEEK with PTFE.
Lots of options.
For common pumps we did injection mold them, but for low volume we just machined from bar (don't use sheet).

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P.E. Metallurgy, Plymouth Tube

 

[JJPellin]

The materials I am most familiar with are PEEK, Vespel (CR-6100), Torlon, Florostint, Graphaloy and carbon graphite. We occasionally use pure Teflon. Specific to wear rings and not other wear parts, PEEK, Vespel, Torlon and Graphaloy are the most common choices. I am not an expert on how these parts are made. Most of them are stocked in bars or tubes and we machine the parts in our shop.

Johnny Pellin

 

[Vikumar]

Thanks JJPellin & EdStainless for your reply

 

[Vikumar]

JJPellin & EdStainless, Can someone help me on how to fix the Wear Ring OD and ID dimensions for Vespel (CR-6100) material? What is the common rule to retain the clearance from Impeller OD to Wear Ring ID? And similarly when we press fit the Wear ring OD under the Bowl ID, what is the press fit rule?