The spherical head also called ball head, is a spherical part of the spherical shell formed by the head, a hemispherical head and the ball head two without folding. The pressure vessel uses the hemispherical head as the end head, its advantage is that under the same volume, the surface area is the smallest, and the thickness is the same under the same pressure condition. Flapless spherical head and simplified by fillet weld connecting the middle head, commonly used as a container of two independent pressure chamber, but also can be used for head. The spherical head also called ball head, is a spherical part of the spherical shell formed by the head, a hemispherical head and the ball head two without folding. The pressure vessel uses the hemispherical head as the end head, its advantage is that under the same volume, the surface area is the smallest, and the thickness is the same under the same pressure condition. Flapless spherical head and simplified by fillet weld connecting the middle head, commonly used as a container of two independent pressure chamber, but also can be used for head