Expansion Joints - Type MWL | Macoga

Macoga MWL Lateral Expansion Joints

Macoga MWL are metallic expansion joints of the universal lateral tied type, supplied with welded ends. The assembly consists of two bellows, an intermediate pipe, and a tie rod system designed to absorb the pressure thrust generated by internal pressure. The corresponding flanged version is designated as MFL.

Operation and Allowable Movements

The MWL type is primarily used for lateral displacement in piping systems. Lateral movement capacity depends on:

• Angular deflection capability of each bellow,
• Length of the intermediate pipe,
• Arrangement and number of tie rods,
• Thermal expansion of the central section.

With two tie rods at 180°, both lateral and angular movement are possible. With three or more tie rods, movement is practically limited to lateral displacement. Axial or additional angular movements require special design considerations.

Typical Applications

• Z-shaped piping sections in a single plane,
• Networks with lateral movement in multiple directions,
• Steam, hot water, thermal oil, or process gas lines,
• Industrial systems requiring welded connections and pressure thrust restraint.

MWL vs. MWA / MWY

• MWA: Single unrestrained, mainly axial movement, no pressure thrust restraint.
• MWL: Universal tied, two bellows, lateral movement in one or more planes.
• MWY: Double hinged, lateral/angular movement in one plane via hinges.

Installation and Inspection

MWL joints are not intended for correcting misalignment. Remove yellow transport bars before pressure testing. Protect bellows from impacts, scratches, arc strikes, and weld spatter. For hydrostatic testing, use chloride-free water.

FAQ

Does it restrain pressure thrust?
Yes, via the tie rods. Proper guides, supports, and anchors must be installed per piping design.

Is an actuator required?
No. This is a passive piping component.