Page 237 - Pressure Vessel Design Manual

Special Designs 215

e Detcvnine area (4 ring required, A,. Required moment of inertia, I,.:

t,, = required thickness of shell for external pressure
Ring only Ring-shell
t, = smaller of (t. - trJ
ADiAT
I
I, = AD: AT I, =-
or ~ 14 10.9
(4.2 - trq 1
~
Reinforcement Required at Small End Due
to External Pressure
A, = 4t,&
0 Determine area of reinforcement reyuirid, A,.

A, = AI. - A,

If A, is negative, the design is adequate as is. If A, is
positive, a ring must be added
KFLR, tan (Y
A, =
e If a ring is required SSEI
Assume a ring size and calculate the following: where FL is the largest compressive load at small end and
El = 1.0 for butt welds in compression.
‘4, =
0 Determine area of ring required, Ar.
1
Lr. = 0.5,G

or
I
A)
-
tcl COS (YCOS(CI~
trs

LI
-RI,tan CY +-+ R2 - Rt
M= where t, is the thickness required of the small cylinder
2 2 3R1,tan (Y
due to external pressure and A is from Table 4-4 as com-
puted for the large end.
fl, = P,M + \7~. tan (Y
A, = A, -A,

If A, is negative, the design is adequate as is. If A, is
positive, a ring must be added.
e Ifa ring is required.
A = using calculated value of B determine A from appli-
cable material chart of ASME Code, Section 11. For Assume a ring size and calculate the following:
values of A Falling to the left of the materialkernpera- A, =
ture line:

L, = 0.5JRStl