|Reg. 198, Reg. 199, Reg. 200
Circular flat ends of drums, etc., supported only at edges
||For these ends C in Equation
35 shall be taken as 140 when the plates are not exposed
to flame, and 122.5 when they are exposed to flame. In
this case the circle D shall pass through the centres
of rivets or bolt securing the end be less than 4 times,
the thickness of the end plate but in no case less curvature.
||Where flanged the inside radius
of curvature at the flange shall not be less than 4 times,
the thickness of the end plate but in no case less than
Bar or bulb stiffened end plates and smoke-box tube plates
of Loco-type boilers
Where such plates instead of being supported by stays are stiffened
in the steam space by substantial tee or angle bars securely
riveted to the plate and extending across the plate to within
the margin allowed by the Equation(35) or where such plates are
formed with a deep bulb extending across the plate to well within
the margin allowed, for the support thus given.
C shall be taken as equal to 80 and 70 for plates not exposed,
and exposed to flame respectively. The margin or pitch for such
stiffening shall be measured from the centre line of rivets
or commencement of curvature of bulb provided it is not more
than 2 inches from the centre line of bulb.
For the flat plate above the stiffener or bulb, C shall be taken
as the mean of the values appropriate for the points of support.
Flat plate margins
The amount of support in relief of stays which may be credited
to the sides of shells, furnaces, uptakes, fireholes and foundries
rings to which flat plates are attached shall not exceed that
found by the following formula :
|Width of margin
in inches =
||C ( t - 1 )
t = thickness is 32nds of an inch
W. P. = Working pressure in lbs. per sq. inch.
C = 3.47 for plates exposed in flame.
C = 3.70 for plates not exposed to flame.
Where the plates are flanged the margin shall be measured from
the commencement of curvature or from a line 2-1/2 times the
thickness of the plate distant from the side of the flange next
to the inner radius of the corner whichever is the less. In
other cases, the margin shall be measured from the centre line
of rivets in the nearest row of the seam by which the flat plate
Doubling plates shall cover the area supported between the stays
and extend beyond the stays so that the centre of the rivets
securing the doubling plate to the end plate shall be at least
half the distance from the outermost stays to the nearest substantial
point of support.
Where flat end plates are flanged for connection to the shell
the inside radius of flanging shall be not less than 1.75 times
the plate thickness with a minimum of 1-1/2 inches.