Use of Vespel in boiler feed pumps

[PowerPlantGuy]

We are considering using Vespel material for boiler feed pump stationary wear rings. The service is water at <375F. The vendor has proposed a running clearence of only 5 mils on the radius.

Any comments appriciated.

 

[MikeHalloran]

The performance of Vespel is impressive.

So is the price. Get a quote.





Mike Halloran
Pembroke Pines, FL, USA

 

[poppeye]

Flowserve Seal Division offers this type of material for Impeller rings, inner stage seal rings and sleeves under their trade name AR/WT offered by Greentweed . It is quite pricey but well worth the money. Clearances can be set to normal allowable clearances. Normally on these types of pumps a hardened Stainless material is used, you then have to double the nominal clearances to account for thermal expansion and possible contact and gauling. Also by using this material your pump performance is increased due to the tight fits betweed moving parts and less internal recirculation across the wear rings or through the innerstage seal / sleeve area. Also the use of this material can double your MTBR with your pump from internal wear and wiredraw across crittical areas. But, this repair is only as good as the small details done during and prior to the assembly phase. Ensure all impellers are balance individually per ISO. Shaft is straight and all registered fits are are not compromised. You will be impressed. Either have your repair center or yourself contact your nearest Flowserve Seal Division Representative for details of this material.

 

[JJPellin]

We have installed Vespel in about a dozen BFW pumps and a few others in hydrocarbon service. We have had very good results. We did not install this material in order to get higher efficiency or extra capacity. We did it to survive flow transients and dry run events without major case damage. We had one of these pumps run for 15 minutes with the suction line completely blocked in. We had to overhaul the pump and swap out the rotor assembly, but there was not case damage. This one event paid for the extra cost with all of the pumps. There is a paper being presented at the International Pump Users Symposium in Houston in the spring about Vespel conversion.

 

[JohnNabors]

sjpearson-

I don't know if you will be machining these parts at your facility but if you are, read the MSDS on Vespel -very- carefully before machining!

John Nabors

'Heaven is the place where the police are British, the chefs are Italian, the mechanics are German, the poets are French, and it is all organized by the Swiss.

Hell is the place where the police are German, the chefs are British, the mechanics are French, the poets are Swiss and it is all organized by the Italians.'

 

[poppeye]

sjpearson,
Read this information on Vespel. It will tell you all about the properties associated with this product.

http://www2.dupont.com/Vespel/en_US/Literature/233630a.pdf