|The uptakes shall
be formed from seamless or electric resistance welded
or fusion butt welded pipes by electric arc process. The
tolerances on these pipes shall comply with the requirements
of Regulation 345.
The uptakes shall be fusion butt welded to the upward
flange of the opening of the furnace crown plate in accordance
with Figures XII/3 and
XII/4.The depth of the flange
of the firebox crown plate opening from the commencement
of the curvature of the flange shall be not less than
twice the of the curvature of the flange
shall be not less than twice the plate thickness with
a minimum of 1 inch. Unless the whole boiler is to be
subsequently stress relieved the uptake and firebox crown
plate shall be effectively stress relieved after welding.
Where the firebox crown plate is also fusion welded to
the body of the firebox as in Fig
XII/15 the firebox
complete with the uptake shall be effectively stress relieved
by heat treatment on completion of all welding.
The uptake may be attached to the shell crown as indicated
on Fig XII/16 before the boiler is finally stress
relieved by heat treatment.
Where the vertical seam of the uptake is fusion welded
the welding shall comply with Regulation
558 and the weld shall be so arranged that it is
externally and internally see Fig XII/34 .
It is desirable that the uptake should be fitted with
an internal cast iron liner extending below the low