Further, two-thirds of this material must be emplaced at a distance from the

centerline of the 40.0 inch opening equal to 26.73 inches. It was decided to

use a balanced reinforcement (equal thickness of reinforcement on the top and

bottom surface) as shown here in Figure 2-12. This is a forged section. The

1.0 inch wall 40.0 inch inner diameter cylinder is welded to the top of the

forging with a full penetration weld. (See Article D-4 and Figure

AD-610.1(a).) A 2.0 inch radius fillet weld is laid in and ground as shown.

Again the taper transition is equal to 3 times the height of the rise to the

top of the reinforcement surface. As in the case of the viewport reinforcing

ring, this configuration must use some other method than the "Stress Index

Method" for a fatigue evaluation.

(10) Door. The "door" falls into the classification of an

appurtenance and its design should be governed by the criteria described in

Chapter 3, "Appurtenances" of this manual. Its design will generally be

quite complex and may require experimental evaluation to meet the

requirements of Section VIII, Division 2. It must be so evaluated because it

does form a part of the main pressure boundary of the vessel.

However, as

an example of how "design by analysis" may be applied in this case a

torispheroidal or equivalent elliptical head and flange arrangement shall be

designed. The flanges are to be secured by some clamping arrangement. Bolts

could apply for a Class II vessel; some "C" type clamp arrangement could

apply for a Class I vessel. This example shall not go into the method of

hinging or clamping the "door."

o Design of head - the head was chosen to be an

ellipsoidal one where D/2h = 2. Here D is the

inside diameter of the 40.0 inch cylinder and

h is one-half the minor axis of the ellipse.

Thus h = 10.0 inches. Further, this head has an

L/D = 0.90 and a r/D = 0.17, where L is the inside

radius of the spherical portion of the head

and r is the inside radius of the toroidal section.

Thus L = 3.60 inches and r = 6.8 inches.

o To determine the minimum thickness of this head

apply paragraph AD-204.3. This paragraph requires

that tmin is the larger of

KPD

t =

2S

or

PD

t =

2S - P

where t = minimum thickness, inches

P = internal pressure plus a static head, psi

d = inner diameter of major axis, in this case

the inner diameter of the cylinder, inches

S = factor from Table AD-150.1 times Sm, in

this case 1.0 Sm psi

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