Flue Duct Expansion Joints Flue Duct Expansion Joints - Effox-Flextor

Expansion Joints Design GuidelinesExpansion Joints ProfilesMovementsBelt TypeThis expansion joint profile is mountedparallel to the plane of the duct.Axial CompressionThe dimensional shorteningof the expansion jointface-to-face gap parallelto its longitudinal axis."U" Design - Integrally Flange TypeThis expansion joint profile incorporates itsown flanges which are perpendicular tothe plane of the duct.Double Flow LinerThe double flow liner is used in systemswith large duct movements andelevated temperatures.Single Flow LinerIn positive flue gas systems with flushmount composite designs, baffles arerecommended to extend the life of theexpansion joint. In negative systems, asingle flow liner is used to prevent thejoint from being pulled into the flowcausing the joint to fail prematurely fromflutter and erosion.Insulation PillowAn insulation pillow is recommended forall composite joints continuously operatingat temperatures 800ÞF (426ÞC) andabove. The insulation pillow keeps belttemperatures down and increases theservice life of the joint. The pillow consistsof fiberglass or ceramic fiber (determinedby flue gas temperature) encased in hightemperature fabric and/or stainless steelmesh. An insulation pillow is also suppliedin heavy fly ash environments to preventash buildup between the flow liner andthe expansion joint.Axial ExtensionThe dimensional lengtheningof the expansion jointface-to-face gap parallelto its longitudinal axis.LateralThe dimensional displacementof the inlet and theoutlet flanges of theexpansion joint perpendicularto its longitudinal axis.Torsional RotationThe twisting of one (1) endof the expansion joint withrespect to the other endabout its longitudinal axis.Angular RotationThat movement whichoccurs when one (1)flange of the expansionjoint is moved to an out-ofparallelposition with theopposite flange.