关于几种形式封头特点的比较

压力容器封头的选型和制造一定要兼顾成本和制作的难易程度，一般优选椭圆型封头和蝶形封头。采用标准椭圆形封头，其封头壁厚近似等于筒体壁厚，这样简体和封头就可采用同样厚度的钢板来制造。这不仅可以给选材带来方便，也便于简体和封头的焊接。蝶形封头的主要优点是便于手工加工成型，且可以安装现场制造。它的主要缺点即受力情况不如椭圆形封头好。

On the Characteristics of Several Forms of Head

The cost and difficulty or facility of producing must be taken selection and manufacture of pressure vessel head into account.Generally the ellipsoidal head and butterfly head are optimized.Standard ellipsoidal head,wall thickness approximately equaling to the cylinder wall thickness,so that the cylinder and head can be manufactured using the same thickness of steel plate.The material selection will be not only taken easily,but also the welding of the cylinder and head is facilitated.The main advantage of the butterfly head is easy to hand-molding process,and can be installed on-site manufacturing,but its main disadvantage is that the forces is less than ellipsoidal head.