Expansion Joints - Type MWT | Macoga

Macoga MWT Axial Expansion Joints

Macoga MWT are metallic axial expansion joints of the single tied type, featuring a single bellows, weld ends, and a tie rod restraint system. The flanged version of this series is designated MFT and is supplied with fixed flanges.

Network Operation

Tie rods limit pressure thrust, reducing main anchor requirements compared to unrestrained axial expansion joints. The series is primarily used for axial movement and minor lateral displacement. Angular movement is permitted only with a two-tie rod configuration; multi-plane angular movement is not supported.

Typical Applications

• steam and condensate lines,
• hot water, superheated water, and thermal oil,
• industrial process piping,
• compressed air and inert gases,
• lines requiring welded connections and pressure thrust control.

Final selection must consider DN, pressure class, temperature, axial travel, lateral offset, cycle life, bellows material, possible internal sleeve, and fluid chemical compatibility.

MWT vs MWA

• MWA: single unrestrained, no pressure thrust restraint system.
• MWT: single tied, with tie rods to absorb pressure thrust.
• MFT: same single tied principle, but with flanged ends.

Installation and Inspection

MWT joints are not intended for pipe misalignment correction. Prior to installation, verify nameplate data, flow direction (if internal sleeve is present), bellows condition, and gasket positioning. Protect bellows from impact, scratches, arc strikes, and weld spatter.

Remove yellow transport bars before pressure testing. Use chloride-free water for hydrostatic tests. Periodic inspection should check for leaks, pressure loss, vibration, corrosion, loose tie rods, and debris accumulation between convolutions.