Several Common Types of Pressure Vessel Heads


Several Common Types of Pressure Vessel Heads

There are four common asme pressure vessel dished heads,this is also called asme pressure vessel tank heads,they are used in the manufacturing of tanks and vessels for the pharmaceutical, chemical, biotech, cryogenic and food and beverage industries. they are:ellipsoidal head, hemispherical head and torispherical head.

Ellipsoidal Head

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 is usually made with Carbon steel, stainless steel, austenitic and non ferritic metals that can be cold worked.

Torispherical Head


A torispherical dome is the surface obtained from the intersection of a spherical cap with a tangent torus, as illustrated above. The radius of the sphere R is called the “crown radius,” and the radius a of the torus is called the “knuckle radius.” Torispherical domes are used to construct pressure vessels.

Let c be the distance from the center of the torus to the center of the torus tube, let a<c be the radius of the torus tube, and let h be the height from the base of the dome to the top. Then the radius of the base is given by a+c<R. In addition, by elementary geometry, a torispherical dome satisfies.




The transition from sphere to torus occurs at the critical radius.

NumberedEquation3 (1)

so the dome has equation




The torispherical dome has volume



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.

1.Diameters available from 18″ – 60″ ID

2.Material Thicknesses available from 12 gauge – 7 gauge

Tank Heads

Non-ASME tank heads for atmospheric or low pressure applications include Standard, Shallow, Reversed Flanged and Dished, Flanged Only, Dished Only, Dished and Flared and Conical heads. Special or stock tank heads are available upon request.

Tank head diameters include 9″ to 118″, 14 gauge to ½” thick, from stainless steel, nickel and specialty alloys such as Hastelloy™, AL6XN, Duplex 2205, and Inconel. Available unpolished or polished with our state-of-the-art CNC polishing equipment. All tank heads available with custom welds prep such as tapers, bevels, lands, or squared.

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