Large Diameter Flange with small hub thickness vs thick pipe 2

[wcw1985]

Hi All,

I encounter a question which would like to discuss. I have a vessel, OD 46"(1168.4mm), have one side SE2:1 dish head another side end with large diameter WNRF #300 flange (46") with blind as a manhole.

Design Pressure: 50 bar
Design Temp: 50 degC

Shell using 1"(25.4mm) Boiler Plate. (Minimum calculated required thickness is 22mm)

Available large diameter flange 46" seems to only available in two thickness which is sch std(9.53mm) and XS(12.7mm).

If i follow the welding method according to ASME VIII Sec.1 UW-9,

removing the thickness from shell plate will result the actual thickness less than required thickness calculated according to UG-23(c).

Any suggestion?

Regards,
wcw

 

[XL83NL]

I think the welding end of your flange (B16.47 flange?) should have a thickness equal to the shell end.
How else can that part of the PV be rated at design conditions?

However, Ive never worked with B16.47, so Im not sure if u can order these as B16.47 series x 46" x 1" wall thickness, WNRF Cl 300

 

[wcw1985]

XL83NL, i myself also think that the hub end thickness of the wnrf should have the same thickness as connecting pipe.

Even i check from Texas Flange website, they only have sch std and sch XS for such size of flange.

Anyway thanks for reply.

 

[SnTMan]

wcw1985, generally speaking, bore is to be specified by the purchaser. See for example B16.47 Table 5-15, Note 5.

You may have to find a vendor who will let you do so.

Regards,

Mike

 

[marty007]

wcw1985,

Texas Flange will certainly supply a flange with any bore you specify.

The table you were looking at Flange Wall Thickness is very poorly labeled. This is just a typical pipe schedule table for if you're using pipe components. I'm guessing at 46" you're not using pipe anymore, so your wall thickness doesn't match the table.

If you look at their tables labeled ANSI B16.47 SERIES A FLANGES, you'll see that the bore dimension is "to be specified by purchaser".

The OD of the flange where you weld to the pipe will match the OD of the nominal pipe size, in your case 46", but the bore must be specified by the purchaser.

Cheers,
Marty

 

[wcw1985]

Thank you SnTMan and Marty for your guy's great advise.

Regards,
wcw