308/311 Series Multi-Ply Expansion Joints
The Keflex™ 308 and 311 Series Multi-Ply Expansion Joints represent Flex-Weld’s industry-leading solution for managing thermal expansion and vibration in piping systems. Designed and manufactured to EJMA standards, these joints feature multi-ply stainless steel bellows that provide flexibility, pressure capability, and reduced spring rates for easier installation and smoother operation.
With pressure ratings from vacuum to 600 PSI, and available in a wide range of end configurations and materials, the 308/311 Series can handle everything from corrosive chemical service to high-temperature exhaust and power applications. Engineered for superior fatigue resistance and low actuation force, these expansion joints deliver long service life, reduced maintenance, and dependable performance in critical HVAC, industrial, and energy systems.
Features & Benefits
– Multi-ply stainless steel bellows construction provides layered protection against corrosion and fatigue
– Lower spring rate reduces end load and actuation force for easier installation and operation
– Extended cycle life and superior fatigue resistance compared to single-ply designs
– Optional internal stainless steel flow liner reduces vibration, turbulence, and temperature on the bellows
– Optional external shroud protects against mechanical damage and insulation pinch
– Integral shoulders prevent bellows inversion during compression
– Tie rods with spacers (optional) prevent over-elongation and over-compression
– Available in single or dual configurations, with universal, gimbal, and hinged options
Applications
– Thermal expansion control in high-pressure piping systems
– HVAC and building service piping
– Steam, condensate, and hot water lines
– Power generation and chemical processing systems
– OEM mechanical and process equipment
– Exhaust and turbine ducting
Markets Served
– Power Generation
– Chemical and Petrochemical Processing
– HVAC and Building Infrastructure
– OEM Equipment Manufacturing
– Industrial and Energy Systems
– Aerospace and Marine Engineering
308/311 Series Submittals (downloadable PDFs)
Need a custom flexible metal solution?
If your system requires non-standard movement, pressure, or connection configurations, Flex-Weld engineers can design and fabricate custom expansion joints, metal bellows, and flexible hose assemblies to your exact specifications. We’ll tailor materials, end fittings, ply count, and cycle life to meet your application—whether it’s HVAC, power generation, chemical processing, or aerospace.
