Such valves play a significant role to prevent to dripping of expensive and dangerous liquid of fluid from the cylindrical source. The other major role of the bellow seal valve is to regulate the flow of liquid when air disturbs the flow rate of the liquid through a pipe. To cap it all whenever there arise a situation to cause a restriction on the air to affect the flow rate of fluid in a given process bellow seal valves are utilized. You can purchase bellow seal valve from 15 mm to 40 mm in size from oriental enterprises. At the same time the valves are having testing design API 602 and testing standard API 598. The material of the valve is A105, F304, and F316.