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Pressure Vessel Heads

Ellipsoidal Head, Hemispherical Head and Torispherical Head are three types of ASME Pressure Vessel Dished Heads.

This is also called a 2:1 elliptical head. The shape of this head is more economical, because the height of the head is just a quarter of the diameter. Its radius varies between the major and minor axis.

A sphere is the ideal shape for a head, because the pressure in the vessel is divided equally across the surface of the head. The radius (R) of the head equals the radius of the cylindrical part of the vessel.

These heads have a dish with a fixed radius (CR), the size of which depends on the type of torispherical head. The transition between the cylinder and the dish is called the knuckle. The knuckle has a toroidal shape.




Most common types of Torispherical Heads


This is a torispherical head. The dish has a radius that equals the diameter of the cylinder it is attached to. The knuckle has a radius that equals a tenth of the diameter of the cylinder.



  • This is a torispherical head also named Semi ellipsoidal head (according to DIN 28013). The radius of the dish is 80% of the diameter of the cylinder (CR = 0.8 x D0.). The radius of the knuckle is (KR = 0.154 x D0). 


 Materials & Type