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The longitudinal seams of shell belts shall be butt-jointed
with double straps when the diameter or Working Pressure exceeds
the limits stated below :-
| Type of Boiler |
When diameter
exceeds
(feet) |
When Working
Pressure exceeds
(lbs/sq. inch) |
| Loco Types |
2½ |
200 |
| Vertical Types |
6 |
125 |
| Other Types |
6 |
80 |
Reg. 109
SHELLS, ANGLE RINGS, BUTT STRAPS, ETC.
Butt Straps
Butt straps shall be cut from the shell plates, or, alternatively,
all the butt straps of each required thickness shall be cut
from one plate. The lengths of the straps wherever practicable
shall be transverse to the direction of rolling of the plate.
Straps shall be pressed or bent in rolls to the shell curvature.
Reg. 110
SHELLS, ANGLE RINGS, BUTT STRAPS, ETC.
Thinning of Butt Straps
Thinning of the ends of the butt straps which tuck under
shell rings, shall be done cold by machine and not by heating
or hammering. The shell plate shall be notched out to receive
that thinned end of the butt strap, so that there shall be no
undue thinning of the butt strap.
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