Boiler Feed Pump and a Worn Out Seal Face

[Milkboy]

Hello Group

I have got a cartridge seal from a boiler feed application.

356°F (180°C) at 246 Psi (17 BarG) with a cooled chamber and the seal also has a cooled seat.

What I have is an Antimony impregnated Carbon versus a Sintered Silcon Carbide equiped mechanical seal.

The Carbon face has worn a heavy groove into the Silicon face and then off course leaked with some flashing off which has pitted the carbon face slightly.
The carbon 'nose' height remains visually as new.

I think some 'solids' or 'fine' have embedded in the softer carbon and ground away the Silicon. Agree or disagree?

I'm having a head scratch as to what the solids are and where they originate.

Am I right in thinking Boiler Feed apps often have a Magnetic Particle Filter to remove these 'fines'??

One point I think may be relevant is the pump and boiler are new and the pump has an iron impeller.
The water is softened
A water analysis is to be arranged.
I dont know the pH Im afraid

Any advice welcomed

Thanks


M



-
Milkboy

 

[imok2]

If there are grooves in the seals, this could indicate that there is a high level of suspended or dissolved solids that need to be addressed. Is your blow down working properly?

 

[rmw]

The "fines" may not be magnetic. They could range from plain old dirt from poorly stored and installed piping to slag particles from pipe welding to name just a couple. Might also be residue from the resin beads in the softener that washed out and went through the pump.

There are lots of gremlins with a new installation until it all finally gets cleaned out.

rmw

 

[chief]

With a new installation, you are likely to have some debris remaining in the pipework for sometime. Consider fitting a temporary cyclone separator in the feed pump discharge to catch those fines.

 

[JJPellin]

Is this a boiler feed or boiler circulation service? We tend to see magnetic particles as a problem in boiler circ pumps. The material comes from the boiler tubes and usually looks like a red pasty material. We regularly use magnetic separators to remove it from the API plan 23 system. But in boiler feed applications, this is not usually seen. All of the above suggestions are correct.

Johnny Pellin

 

[longeron]

I second Johnny's observations. Rust should be pretty obvious. It will stick to the seal hardware even after the seal has been removed from the pump- usually by the mating ring and gland plate, or in the retainer.

I have seen an applicaton where the soft Carbon face ground into a SiC. It was in refrigerant, a very poor lubricator not completely unlike BFW. The best theory we had for that kind of wear was that some of the SiC became embedded in the Carbon turning the primary ring into a grinding wheel. I had to save those faces for show and tell training sesions. Nothing like seeing the exact fit that the face ground for itself to drive how bad a lack of lubricaton is. I mean exact fit as if they were made that way on purpose.

What exactly did you mean by cooled chamber and cooled seat?