I) General

A 2:I Semi Ellipsoidal D ished Head is that in which half the minor axis i .e. H - hr (inside depth of head minus the straight flange) equals one fourth of the inside diameter (D). Please refer Illlustrative Fig. I.0.1.

Where,

D = Inside Diameter in mm
Do = Outside Diameter in mm
h1 = Straight Flange in mm (Measured in inner diameter)
H = Inside Depth
C = Circumference (TT Do) in mm
Tmin = Minimum Wall Thickness(after forming) in mm
Kr = Knuckle Radius: 0.17D( Minimum) in mm
R = Crown Radius:0.9 D (Maximum) in mm
ai = Deviation of Straight Flange from inner cylindrical Shape
ao = Deviation of Straight Flange from outer cylindrical Shape
O = Out of Roundness in %
= 2 (Dmax - Dmin) x 100
(Dmax - Dmin)