System Technology – Axial

Expansion joints in axial pipe systems move parallel to the pipe centerline. This common configuration includes straight piping with main anchors at the end of a run to react pressure force, spring force, alignment guide friction force, and support friction force.

DIAGRAM #1
Single expansion joint used to absorb axial pipe line movement and positioned as shown between two main anchors.

DIAGRAM #2
Two Expansion Joints in longer pipe run than that shown in Diagram #1. Intermediate anchor between main anchors form individual expanding and contracting sections. Expansion Joints are installed between intermediate and main anchors.

DIAGRAM #3
Expansion joints, guides and anchors, absorbing movement in piping layout with branch connection. Anchor at the junction serves as a main anchor and is designed to resist thrust from the branch line expansion joint.

DIAGRAM #4
Expansion joints, guides and anchors, absorbing axial pipe line movement in a piping system having a reducer. One main anchor at reducer (center of diagram) is designed to resist the differential in the thrust of both expansion joints.

Benefits

Lowest cost expansion joint products
Lowest pressure drop if there are no changes in direction
No change in direction required

Considerations

Highest system install cost from anchor size and number of alignment guides
Highest expansion joint and system forces, including pressure force
Highest forces and risk, pressure thrust applies
Main anchors required
Maximum number of alignment guides
Not typically used for hanging or rooftop systems
For lower system forces and install costs, consider a lateral system or pressure balance configuration
Main anchors, supports, and alignment guides are required for correct operation and safety

Applications

Tunnel, ground-based, riser, or buried energy distribution systems across large distances where anchors are practically located at ground level or to substantial structures
Commercial, Industrial, Power Generation, Petrochemical, Marine, Defense, and Laboratory of all sizes and pressures