Opening on Blind Flange

[taba94]

hi engineers
i want to design a 20L reactor with 20bar pressure and 200c temp and on top of it there is a STD. 10 inch blind flange. there should be a mechanical stirrer mixer in the reactor and i should consider an opening on the blind flange but i dont know how much diameter i should consider for it and how much is allowable to consider. and also i should consider about 4 extra opening for other instruments such temp/pressure/ph/etc. on the blind flange.
these are my questions:
1- how much diameter i should consider for mechanical stirrer?(considering the mechanical seals that should be located there and also i dont know the diameter of that)
2- how much is allowable for opening diameter on blind flange?
3- is it allowable to make 4 more 3/4 in opening on the blind flange around the stirrer opening?
Code design ASME BPVC SEC. VIII DIV.1
thank you.

 

[SnTMan]

taba94, for starters, review UG-39. I doubt anybody can guess dimensions for your Q1.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[moltenmetal]

Your flange will become an Appendix 2 designed flange. You may, or may not, be able to make the required designed flange out of a hubbed blind flange. Any more than one central opening in a blind flange renders it a component outside the scope of its original design code i.e. B16.5 in this case. The single opening must also fall within the limits set out in B16.5, beyond which the blind flange becomes a reducing flange and hence needs a hub.

 

[taba94]

According to pressure/temp rating i shall use ansi flange class300. Is it possible to use a class600 flange to solve this problem because i dont want to desin and order a new designation to be forged. i want to buy a std flange.

 

[TGS4]

Do the calculations yourself and figure it out. Or pay someone with that expertise to do it for you.

 

[taba94]

its easy to design it(by codecalculation by PVElite) but it will cause lots of trouble to be forged.

 

[XL83NL]

Forging a blind flange? TGS4 has put it gentle.

 

[taba94]

Sorry i dont understand
What happens when i design a new flange? How can i buy it or made it?

 

[SnTMan]

Blinds / flat covers are often made from plate. See B16.5 or B16.47 for example.

ON EDIT, I'd add: B16.5 sizes probably not usually plate "off the shelf".

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[moltenmetal]

What happens when i design a new flange? How can i buy it or made it?

Your flange will likely be made out of plate, with the required examinations done on the material before you can use it. Unless the MAWP and T are lower than that of the 300# flange you intended to use, you will need a plate which is thicker than the 300# blind flange to make up for missing area from all the holes you're cutting into it.

Note that a B16.5 flange even without holes sometimes fails the Appendix 2 flange calculation due to excessive bolt loading- the Appendix 2 designed flange would need to be thicker.