The selection of head needs to consider a number of factors. The first is the requirements of users, followed by the chemical process requirements, the vertical vessels of solid working media more choose cone head, conducive to the flow of working media. The liquid working medium mostly uses elliptical heads or spherical heads. The stirring pressure vessel should determine the shape of the head according to the shape of the paddle and the flow of the working medium.

　　Also according to the pressure, the pressure vessels in the low and middle pressure use elliptical head;The pressure vessel of high pressure and ultra high pressure chooses spherical head. Of course, it also determined by considering the situation of stress. If a large hole is opened on the stress transition zone of the ellipse head, and the local stress is oversized, the spherical head can also be used.There is also a rare case where some type of head must be used due to the location of the installation.

　　Different types of heads are made by the processing method is different. Taking the torispherical head as an example, cut the blanking sheet to obtain the top plate, circular arc slice and circular annular slice; then the slice to be formed, make the welding groove of circular and circular arc slice, assemble and weld. Make a curve for making the processing mold of the top circular plate between the busbar of the circular curved slice and the top of the head. The top circular plate is drum-shaped under the processing mold, the groove, the top circular plate and the circular arc slice are welded. The temperature of the empty furnace rises to 400℃, the torispherical head put into the furnace, heats up to 625 ± 25℃, keep the temperature, cools to 400℃, and comes out of the furnace to cool naturally. Pickling solution evenly coated the surface of the head, and then rinse it with water. This simplifies the manufacturing process of the torispherical head, which can well eliminate the residual stress caused by the change of the shape of the slice during the welding process, and the obtained product has high strength and high performance.