K = a factor depending on the ratio of P/S as
determined from Figure AD-204.1 for heads
with D/2h = 2.
Here P = 1000 psi and S = 23,000 psi, thus P/S = 0.043.
Enter Figure AD-204.1 with this figure, K is established
as approximately 1.05. Thus we have
1.05(1000.0)(40.0)
t1 = = 0.913 inches
2 (23,200)
or
(1000.0)(40.0)
t2 = = 0.889 inches
2 (23,200) - 1000
t1 governs, so we set thead = 1.0
inch.
o This head or "door" is shown here in Figure 2-13.
o Design of the flange -- The flange could be designed
using the provisions of Article 3-3 of Appendix 3.
However it was decided to use a different type of
flange than those covered by these provisions.
(See Paragraph 3-300.) It was decided to use a
flat-faced flange with sealing by some type of
pressure energized ring-seal backed up by a compressed
"O" ring seal. This seal arrangement is
shown conceptually in Figure 2-13. No attempt
will be made to dimensionally detail them, since
they are basically part of the "door" system and
that in itself is being only approximated in this
design. The upper flange was developed as a 1.5
inch thick ring with an inner radius of 20.0
inches and an outer radius of 23.5 inches. It is
attached to the head by a full penetration weld
with an overlay fillet weld with a smooth, ground,
1.0 inch radius as shown in Figure 2-13. The
bottom flange is basically the same but with a
taper transition 4.0 inches long, at 10 degrees
to the surface of the cylinder as shown. The bolt
circle or clamp contact line is set at a radius
of 22.5 inches. The design of this flange in this
manner was really based on experience. The flat-
face, metal to metal flange was chosen so as to
allow a significant preload to the bolts or clamp
and the flange. If a sufficient preload is
established, then the bolts or clamp will not under-
go any significant load cycles and can be exempted
from fatigue considerations, which for bolts under
Section VIII, Division 2, can be quite limiting.
(See Paragraph 5-120, "Fatigue Analysis of Bolts,"
and also see Article 3-5.)
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