Two independent metal bellows elements fitted with pipe liners and a single external shell. This style of joint is most suitable for applications involving movements in long piping runs with large amounts of thermal expansion. Also recommended where maximum system safety is an issue, and protection of the bellows element is essential.
The joint is externally pressurised. With an internally pressurised bellows the movement capability is restricted by the squirm pressure. When the bellows is pressurised externally it becomes pressure stabilised irrespective of the length to diameter ratio thus allowing the use of a greater bellows length at a given pressure.
A central intermediate anchor foot is attached to the joint as required. Drain ports can be provided in the shell for removing sediment or condensate.
Suitable for large axial movements.
Manufactured to the guidelines laid down in the Standards of the Expansion Joint Manufacturers Association Inc. (EJMA).