A blanking head is an element used to seal the end of a container to isolate its internal and external media, also known as an end cover. The blanking heads for cylindrical containers are generally rotating shells. They can be classified by the shape of their surface into convex, conical, flat, and composite types. A convex blanking head refers to one with an outwardly convex surface, such as hemispherical, elliptical, dish-shaped, and seamless spherical blanking heads, among others. Some gas cylinders use a composite bottom blanking head with the convex surface inward, which ensures both strength and meets safety requirements for use.