Project Description

Externally Pressurized Expansion Joints

In this paragraph, I am going to talk about externally pressurized expansion joints. Firstly they are designed for installations where the principal movement is axial. Secondly standard single and dual designs are available 2” through 24” NPS with 4” through 16” axial compression. Next service conditions are 150 and 300 psig to 500°F. Then welded and flanged end connections are standard, with grooved ends optional. Moreover, Standard in-line pressure balanced configurations are available 2” through 24” NPS with 4”, 6” & 8” axial travel rated for 150 & 300 psig to 500°F. Finally pipe telescopes into the expansion joint protecting the bellows and providing a smooth full bore interior. Additionally contact us for a quote or more information.


• Standard Designs Sizes 2″ through 24″, 150 & 300 PSIG at 500°F
• Axial Travel of 4″, 6″ & 8″ for Single Configurations 8″, 12″ & 16″ for Dual Anchor Base Configurations.

  • Maximum Flexibility and Extended Life
  • Low Spring Forces and Pressure Thrust
  • Standard In-Line Pressure Balanced Configurations

Since the media is on the exterior of the bellows it is self draining, and bellows instability or squirm is not a consideration. Rigid guides on the interior and exterior ensure alignment of the bellows. The proven design of externally pressurized expansion joints excels because of close attention to detail design and high quality workmanship. These designs offer an affordable product with a proven service record without the use
of expensive high nickel alloys.

Externally Pressurized Expansion Joints

Externally pressurized expansion joints are designed for installations where the principal movement is axial. Standard single configurations are designed for 4″, 6″ and 8″ of axial compression (pipe expansion) and 1″, 2″ and 2″ extension respectively. Dual configurations are designed for 8″, 12″ and 16″ of axial compression and 2″, 4″ and 4″ extension respectively. If the primary movement is extension (pipe contraction) the expansion joint can be preset at the factory. The piping system must include anchors to react the force produced by pressure thrust and the bellows spring constant, supports to react the weight of the pipe and media, and guides to ensure that the pipe alignment is maintained.