Difference between spherical and hemispherical heads

The spherical crown head is a part of the spherical surface directly connected with the cylinder. Because of its simple structure and convenient manufacture, it is often used as the middle head of two independent pressure chambers in the container, and also as the end cover. Because there is no corner transition at the connection between the sphere and the cylinder, there are considerable discontinuous stresses on the head and cylinder near the connection, and the stress distribution is not very reasonable. The spherical crown head is often used in the middle head. In order to save the area occupied by the plane and facilitate the process arrangement, some pressure vessels divide the whole cylinder into separate chambers. The design has simple structure and good stress condition.
Hemispherical head and spherical crown head: Under uniform internal pressure, the membrane stress of thin-walled spherical vessel is half of that of cylinder with the same diameter. Therefore, the spherical head is the most ideal structure form from the point of stress analysis. However, the disadvantage is that it is difficult to stamp the whole part with small diameter, and the tailor-welded workload of large diameter stamping with piecewise stamping is also large. Hemispherical heads are often used in high pressure vessels.
The spherical crown head is a part of the spherical surface directly connected with the cylinder. Because of its simple structure and convenient manufacture, it is often used as the middle head of two independent pressure chambers in the container, and also as the end cover. Because there is no corner transition at the connection between the sphere and the cylinder, there are considerable discontinuous stresses on the head and cylinder near the connection, and the stress distribution is not very reasonable. Therefore, generally in low pressure vessel equipment, the ball-shaped head can be used, and the biggest advantage of the ball-shaped head is that any diameter can be customized.