Page 221 - Pressure Vessel Design Manual

Design of Vessel Supports 199
Skirt Skirt thickness required:

0 Thickness required in skirt at compression plate or ring
clue to maximum bolt load reaction. tsk = - or J fb
fb
For Type 3: 8F, 4,640,000

1 .o whichever is greater
Z=
0 Determine allowable longitudinal stresses

Tension
St = lesser of 0.6F,, or 1.33s
1.322
+ [4Ah2]0.333 Compression

S, = 0.333 F,,
For Type 4:
= 1.33 x factor “B”
Consider the top compression ring as a uniform ring with - tskEl
-
N number of equally spaced loads of magnitude. - 16 R
= 1.33s
Pa
-
h whichever is less.

See Procedure 5-1 for details. Longitudinal forces
The moment of inertia of the ring may include a portion of
the skirt equal to 16t,k on either side of the ring (see
Figure 3-75).

0 Thickness required at opening of skirt.
Note. If skirt is stiffened locally at the opening to compen-
sate for lost moment of inertia of skirt cross section, this Skirt thickness required
portion may be disregarded.
G = width of opening, in.

whichever is greater.
0 Thickness required at .skirt-head attachment due to M,.
Actual weights and moments at the elevation of the open-
ing may be substituted in the foregoing equation if Longitudinal forces
desired.

-
Pa
h Skirt thickness required

FLT FLC
tsk = or
Pa 0.707 StE 0.707S,E
h
whichever is greater.
Figure 3-75. Dimensions and loadings on skirt due to load P.