Standard Moulded Rubber Expansion Joints - MAC-W | Macoga

MACOGA MAC-W – Standard Moulded Elastomeric Expansion Joint Without Tie Rods

The MAC-W is a standard single-arch elastomeric expansion joint supplied with loose metal flanges. It is designed for absorption of axial compression/elongation, lateral offset, angular movement, vibration, and pressure pulsations in piping systems. This is an unrestrained type; therefore, pressure thrust is transmitted to the pipeline anchors.

Technical Limits

• Standard moulded sizes: DN25–DN600.
• Custom fabrication: up to DN6000 on request.
• Operating pressure: 16 bar up to DN300, 10 bar for DN350–DN600.
• Typical movements: compression 30 mm, elongation 20 mm, lateral 20 mm.
• Angular movement: up to 35° for small DN, decreasing to 6° at DN600.
• For vacuum service, internal vacuum ring is available.

Materials and Media Compatibility

Elastomer selection is based on process fluid, temperature, and chemical compatibility:

• EPDM: water, hot water, seawater, oil-free air.
• EPDM HT: hot water up to 140 °C.
• NBR: oils, fuels, hydrocarbons, gases; not suitable for steam or hot water.
• SBR / Natural Rubber: wastewater, sludge, liquids with suspended solids.
• FKM / Viton: chemicals, solvents, oils, hydrocarbons up to 150 °C.

Installation

MAC-W is not intended for correction of misalignment. Prior to commissioning, verify anchors, guides, installation length, pressure/temperature/media compatibility, and check for leaks. The elastomeric face seals directly to the pipe flange; no additional gasket is required.

Difference from MAC-WT

MAC-W requires external anchors to absorb pressure thrust. MAC-WT includes control units/tie rods to limit over-extension and absorb axial pressure loads. Selection is based on DN, pressure, temperature, media, movement, vacuum service, and anchoring capability.