Stainless and ductile pipe connection 1

[vodeni]

Need to connect new stainless steel piping with existing ductile iron outside application. Both sides with plain end. The piping is for compressed air, low pressure. Should we weld the flanges or use some type of uniflange, should we worry about disimilarity of material. Do we need a special kind of gasket?

Thanks

 

[MJCronin]

Vivendi..

Let me know about which weld proceedure that you propose to use between ductile iron and stainless steel. I am very, very interested.

Ductile iron is not commonly used in any type of compressed air system. What pressure do you consider to be "low pressure" ?

Is the ductile iron pipng system being "re-used" from another use ? Drainage perhaps ?

-MJC

 

[SteveWag]

This type of connection is done quite often using a Dresser coupling with one end gasket sized for Schedule size pipe and the other end using a gasket sized for AWWA iron pipe. If your diameter is grossly different, use a transition coupling. The only real worry would be the temperature of the air, if high get a hi-temp rated gasket. A plain Dresser coupling will not provide joint restraint. If the ends of the pipe are free to move apart, get a coupling with the added joint restraint. Call your local water utility and get the name of the supplier they use.
Steve Wagner

 

[vodeni]

This is the air for diffusers in waste water treatment plant. The pressure is only about 7 psi. The existing blowers system was piped with ductile iron, and we need to connect to the air pipes in the tanks which are ductile. I wasn't going to weld ductile to stainless, I was going to connect with a flange with a gasket in between hoping to be enough to separate them. I am wondering what kind of flange would be the best and those kind of dilemas.

 

[kenmac777]

Try Victaulic Style 90 or 99 Plain end Couplings. I have used these to join ductile iron to carbon steel pipe on a gen-set cooling circuit running ethylene glycol at 200F.

 

[unclesyd]

I agree that a Dresser type coupling maybe the answer
I would give Acipco (American Ductile Iron Pipe) a call as I believe they did make a fitting for your situation.

http://www.acipco.com/adip/

 

[vodeni]

Thank you all.
Another issue: how to seal a penetration of a stainless pipe through the foundation slab. Should it be grouted or would some sort of seal work? And also the pipe continues vertically for about 12 feet before turn horizontally. The subbase is compacted fill. Should the pipe be embedded in concrete (it's air, or maybe just supported at the bottom where turn horizontally, or not supported at all?

Thanks again

 

[unclesyd]

I have seen something like this used in penetrating the walls of large concrete basins.

http://www.strata-tech.com/manchette/tam_system.html

Back to Acipco. They have specials in DI for wall penetrations. The closest I know about of similar construction in SS is an anchor flange.

http://www.acipco.com/adip/specials/wall/

 

[rconner]

Fyi see

http://www.dipra.org/pdf/gasketsForDIP.pdf

and

http://www.acipco.com/adip/products/Sect11.pdf

etc. (iron piping has been used for some air applications, including that as mentioned on this thread, for many decades – high temperature applications though, such as off some blowers etc. require specific attention to details in this regard). While not necessarily relevant with regard specifically to connecting sleeves with stuffing box type sleeves, as can be seen by the DIPRA sheet push-on joints (that are also less labor intensive and reliant) offer a little better heat performance than even well-assembled mechanical joints.

 

[SteveWag]

If your still wanting to use flanges, weld a 150# S.S. flange to the stainless and use a “Flange Adapter”” on the D.I. pipe. The adapter slides over the plain end of the D.I. and secures with set screws and seals with an O-Ring. The 125# adapter will mate with the 150# S.S. flange. This will provide a restrained connection.

http://www.ebaa.com/Products/1000-2100/1000.pdf

The penetration through the floor or wall should be sealed with a seal, I use Link-Seal made by Thunderline Corp. I usually cast a S.S. sleeve in the concrete wall for new work and core drill a hole for existing work. I would support the vertical run from below, maybe with a haunch poured with the wall or a fabricated support if the wall exists.

http://www.linkseal.com/

Steve Wagner