ASME B16.5 Class 600 Flange Face - Min Raised Face? 3

[f2sealer]

I've been asked to design a flanged joint using a pure copper gasket to seal Fluorine gas at 1000 PSI.

I looked at ASME b16.5 and thought that a class 600 raised face design would work, but couldn't understand what the minimum thickness (width) of the raised face could be. I wanted to I use almost a knife edge face to deform the copper and make the seal.

Does anyone know if there is a minimum raised face width?

Thanks

 

[deanc]

Ideas: See ASME SecVIII Div.1 Appendix 2

 

[MJCronin]

f2sealer,

Have you considered "ring joint" flange faces ?

What does the process piping code, ASME B31.3, say about flange faces for such a dangerous gas ?

-MJC

 

[jte]

f2-

Are you referring to a nubbin?

jt

 

[f2sealer]

Deanc - Thanks for the referance, I'll check it out.
MJC - I had considered a ring joint. I stayed away from it becuase I couldn't locate a standard pure copper O-ring, and was concerned that the bolt torque would need to be very high to deform the metal seal. I was hoping to stay with a simple flat copper sheet as teh gasket. Also, I don't have B31.3. Know of a web resource where I could download? Thanks for the help.

Jt- Yes, I would describe the idea as a nubbin. It's dort of like a ConFlat or DelSeal type flange used in vacuum appplications.

Thanks for the responses.

 

[MJCronin]

jte....

Ive always thought that a "nubbin" was a small, imperfect ear of corn...

http://dictionary.reference.com/browse/nubbin

I do not typically use these in my bolted joints.... (Although, I understand that they are common in the new ethanol plants)

-MJC

 

[jte]

f2-

I can't really help you since basically whenever an exchanger I was working with had a nubbin my recommendation was to machine it off. This aligns with Guideline 2 from

http://www.lamons.com/html/body_cmg-ex.html

for GMGC (kammprofile) gaskets. However, a google search on "nubbin +flange" returned around 550 hits so you will hopefully find some guidance...

For what its worth, the nubbins i had machined off were typically around 1/8" wide x 1/16" raised off the face and were used for double jacketed gasket applications. We were typically replacing the DJ with GMGC's and so knocked off the nubbin. If we were going back with DJ's we'd leave the nubbins on.

jt