Head is a petrochemical, food and pharmaceutical atomic energy to important parts of the pressure vessel equipment and many other industries indispensable. Pressure vessel head is on the cover, is a major component of the pressure vessel pressure. The role of the sealing action. First, make a pot-shaped pressure vessel up and down at the end, the second is the pipeline coming to an end, is not prepared to extend forward, and then use a head in the form of a sealed tube welded to live. And the role of head of similar products are blind plate and pipe cap, but that the two products are removable. And after a good weld head can not be removed. Ancillary fittings pressure vessels, piping, flanges, elbows, tees, crosses, and other products. Head of quality is directly related to the pressure vessel safe and reliable long-term operation.