Q. Formed heads of vessels?

Formed heads are generally of 2:1 semi ellipsoidal form, but other heads may be used, such as hemispherical, torispherical, conical and toriconical.

Design rules to prevent plastic buckling or axisymmetric yielding of thin fabricated torispherical heads subjected to internal pressure. Accordingly, for D/t ratios in the range of 300

When an agitator is mounted on a top head nozzle (or studding outlet), the formed head thickness based on Section VIII formulas for pressure loadings and static local loadings analysis, is often not sufficient to provide the rigidity and stress levels acceptable for the dynamic loadings that will be applied. It is recommended that the agitator manufacturer be consulted prior to ordering the head, regarding the recommended head thickness for the agitator installation under consideration.