Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
(OP)
Stainless Steel wear rings tend to gall/seize when they come in contact with each other causing considerable downtime and cost.
Does similar problem of galling/seizing of wear rings occur on API C-6 pumps with Chrome wear rings.
Any experience out there replacing the Stainless Steel wear rings with Vespel CR-6100 on BFW Pumps. What are the resultant benefits (reduced clearence between rings and improved efficiency, wear rate and failure rate etc).
Does similar problem of galling/seizing of wear rings occur on API C-6 pumps with Chrome wear rings.
Any experience out there replacing the Stainless Steel wear rings with Vespel CR-6100 on BFW Pumps. What are the resultant benefits (reduced clearence between rings and improved efficiency, wear rate and failure rate etc).





RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
thread407-173199: Use of Vespel in boiler feed pumps
RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
Vespel has a very low coefficient of thermal expansion in the radial direction, but a very, very high rate in the axial direction. If the Vespel is cut to exactly fit the envelope where the original wear ring had been, it will grow out beyond the holder, axially, once it heats up. The unsupported projection of this ring would normally be toward the high pressure side of the ring. The OD pressure on this unsupported ring causes it to compress inward against the shaft. When the tip touches off on the shaft, it seals off the pressure drop so that the majority of the ID of the ring is now at the lower pressure and the majority of the OD of the ring is at the higher pressure. This is enough to collapse the ring. This can be avoided in a couple of ways. First, a relief cut on the OD that breaks through to the low pressure side can keep the OD from seeing the higher pressure. And second, cutting the ring shorter, so that at full temperature, it does not extend axially beyond the holder, will keep that unsupported projection from deflecting inward to start the failure process. We made both of these changes and have had no further problems.
In this group of pumps, and in a large number of other vertical and horizontal pumps in a wide variety of services, we have had very good results with Vespel and feel it has reduced vibration and shaft deflection, improved low-flow or no-flow survivability, improved overall reliability and increased efficiency. With a little care in the conversion, I would highly recommend it.
Johnny Pellin
RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
A great post with good information for those who are interested and have a need.
RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
Please contact Erwin Birk (+49 7541 700 77 0)or check their web side www.eplastic.com.
RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump
Certainly highly recommended for BFW pumps!
RE: Vespel CR-6100 for impeller wear Ring on Boiler Feed pump