Externally-Pressurized Expansion Joints
Externally-Pressurized Expansion Joints are Designed to Replace:
- High-Maintenance Packed Joints
- Space-Confining Pipe Loops
- Costly Equalizing Expansion Joints
MULTI-PLY SAFETY FACTORS - In a critical application, a multi-ply expansion joint can, in most cases, preclude a catastrophic failure. If a failure occurs in one ply due to corrosion or fatigue, the intact plies will work as a protective barrier to contain the pressure and the medium until a replacement can be made. Flex-Weld multi-ply expansion joints are designed to provide utmost safety in the event of system failure. The burst pressures are a multiple of the operating pressure making the Flex-Weld multi-ply bellows the most reliable component in the system.
CYCLE LIFE OPTIMIZATION - The technical advantage of using multiple plies of thin wall thickness material is that less residual stresses are introduced at the time the bellows were formed. Overall, Flex-Weld multi-ply expansion joints have lower built-in and induced stresses which ultimately results in longer cycle life. Also, the thinner gauge multiple plies have less localized induced stresses during operation compared to a single thicker ply. The configuration of the convolutions (pitch, depth, contour, number of plies, ply thickness) of FLEX-WELD multi-ply expansion joints are optimized to offer the highest fatigue life.
COMPACT DESIGN - Multi-ply expansion joints have more flexibility than conventional single-ply expansion joints and thus require less live length to accommodate a given movement. The live length of the bellows can be minimized to absorb a given combination of axial, lateral and angular movements. This results in an economical, compact assembly which can be installed in a minimal amount of space. An additional benefit is a small effective area, resulting in lower thrust pressures on the anchors and mechanical equipment in the system.
LOWER THRUST FORCES - The multi-ply design results in lower spring rates. Also, the effective cross-sectional area of multi-ply expansion joints is less, compared to single-ply bellows, to accommodate a given movement. These two reductions result in lower forces and moments on the anchors, equipment and guides. A side benefit is that fewer anchors and guides will be required in the overall bellows piping system.
Brochure for Single Bellows
Brochure for Dual Bellows
Single Bellows Externally-Pressurized Expansion Joints (4” – 8” Axial Movement)
Dual Bellows Externally-Pressurized Expansion Joints (8” – 16” Axial Movement)