Expansion Joints - Type MFA | Macoga

Macoga MFA Axial Expansion Joints

Macoga MFA are metallic expansion joints of the single unrestrained type, featuring a single bellows and fixed flanges. They are primarily used to absorb axial thermal expansion in straight pipe runs. The product family also includes MWA (weld ends) and MFG (loose flanges) variants.

Operation in Piping Systems

The MFA does not absorb pressure thrust. The piping system must be equipped with main anchors, directional guides, and axial guides, designed for system pressure, effective area, thermal movement, and piping loads.

Permitted movements within design limits:

• Axial movement
• Lateral movement in one or more planes
• Angular movement in one or more planes

In practice, MFA is mainly used as an axial compensator between two main anchors.

Typical Applications

• Steam and condensate networks
• Hot water, superheated water, and thermal oil circuits
• Compressed air and inert gases
• Industrial utility loops
• HVAC piping with flanged connections

Selection must consider DN, PN/Class of flange, temperature, axial travel, operating cycles, bellows material, internal sleeve, gasket type, and media compatibility.

MFA vs MFG / MWA

• MFA: fixed flanges
• MFG: loose flanges for rotational alignment
• MWA: weld ends

All three types are single unrestrained and require external absorption of pressure thrust by the piping design.

Installation and Inspection

MFA is not intended for misalignment correction. Before installation, verify nameplate data, flow direction (if internal sleeve is present), gasket positioning, and bellows cleanliness. Protect bellows from impacts, scratches, arc strikes, and weld spatter.

Remove yellow transport bars before pressure testing. For hydrostatic testing, use chloride-free water.