The air pipe head is generally installed at the top position of the ventilation pipe, and the ventilation pipe is kept unimpeded by the shunt function and the protection function to avoid water entering the cabin. Aluminum air pipe head is used on the air pipe of oil tank, seawater tank and freshwater tank as well as for ballast and cargo tank etc.The flange size can be manufactured according to GB,CB, JIS, ANSI, DIN.