Expansion Joints - Type PTFE | Macoga

Macoga PTFE Lined Expansion Joints

Macoga PTFE expansion joints are designed with PTFE (polytetrafluoroethylene) lining on all wetted surfaces. These assemblies are specified for piping systems conveying chemically aggressive media where direct contact between the process fluid and metallic components must be avoided. Macoga offers PTFE lining for both metallic and elastomeric expansion joints, targeting applications involving chemicals, strong acids, corrosive, or hazardous fluids.

Technical Operation

The PTFE lining isolates wetted areas of the bellows and flanges, minimizing corrosion risk to metallic parts. PTFE is selected for its chemical inertness, low friction coefficient, and non-stick surface properties, making it suitable for aggressive process environments.

Suitable Media and Applications

Typical applications include:

• chemical processing lines,
• pulp and paper industry,
• acid transfer lines,
• corrosive liquids,
• hazardous or high-purity media,
• industrial networks requiring isolation of metallic components from process fluids.

Selection should be based on pressure rating, temperature range, chemical concentration, flow velocity, operational cycles, and allowable movement per EN or ASME standards.

Design Considerations

• verify PTFE chemical compatibility with process fluid,
• check operating temperature against PTFE lining limits,
• ensure correct design and test pressure,
• select metallic components per environmental exposure,
• review anchoring, guiding, and pressure thrust loads,
• avoid torsion or unintended lateral displacement.

Installation and Maintenance

Do not use the joint to compensate for misalignment. Remove yellow transport bars before pressure testing. For hydrostatic tests, use chloride-free water to prevent stress corrosion cracking of metallic parts.

Inspection should include leak checks, pressure loss, vibration, external corrosion, anchor/guide condition, and accumulation of solids in convolutions.

FAQ

Are these suitable for steam?
Only if the data sheet confirms temperature, pressure, and PTFE suitability.

What does the PTFE lining provide?
Chemical barrier between process fluid and metallic construction, primarily for corrosive media.