Seal Material Selection Guide
Choosing the right seal materials for different media conditions
Selecting the appropriate seal material is critical for ensuring system integrity, preventing leaks, and maximizing equipment lifespan. Different media conditions require specific material properties to maintain effective sealing performance.
This guide provides recommendations for seal material selection based on media characteristics including corrosiveness, temperature extremes, sanitary requirements, and abrasiveness/viscosity.
Why Material Selection Matters
Incorrect seal material selection can lead to premature failure, system contamination, safety hazards, and costly downtime. Proper material compatibility ensures reliable operation and reduces maintenance requirements.
Seal Material Recommendations
For Corrosive Media
- Acids, alkalis, or salt solutions
- Materials must resist chemical erosion
- Common applications: chemical processing, petrochemical industry
Recommended Materials: Polytetrafluoroethylene (PTFE) withstands most strong acids and alkalis. Ethylene propylene diene monomer (EPDM) is suitable for mild corrosive environments, especially alkaline media. Avoid: Nitrile rubber, which is prone to swelling or breaking down.
For High or Low Temperature Media
- High-temperature: hot steam or industrial exhaust
- Low-temperature: refrigerants or cryogenic fluids
- Materials must maintain stability at temperature extremes
Recommended Materials: For high temperatures, graphite-based seals retain integrity and resist oxidation. Fluorinated rubber works for moderate high temperatures. For low temperatures, nitrile rubber stays elastic without becoming brittle. Consider: Thermal expansion coefficients and long-term heat aging properties.
For Sanitary Media
- Food processing, pharmaceuticals, medical applications
- Non-toxic, easy-to-clean seals required
- Must prevent contamination and meet regulatory standards
Recommended Materials: Silicone rubber meets sanitary standards, has no harmful leachables, and is easy to sterilize. Food-grade EPDM resists mold growth and can be thoroughly cleaned. Essential: Verify materials have relevant certifications (FDA, USP Class VI, etc.) to comply with hygiene regulations.
For Abrasive or Viscous Media
- Abrasive: slurries or dust-laden fluids
- Viscous: oils, pastes, or thick solutions
- Materials need wear resistance and anti-adhesive properties
Recommended Materials: Polyurethane has high toughness and resists scratching from particles. Reinforced PTFE has a smooth surface that prevents medium adhesion. Avoid: Soft materials that are easily worn down or clogged. Consider hardened or composite materials for extreme conditions.
Selection Considerations
When selecting seal materials, always consider the specific media properties, operating conditions, and system requirements. No single material is ideal for all applications—the best choice depends on a careful evaluation of chemical compatibility, temperature range, pressure conditions, and regulatory requirements. Consult material compatibility charts and manufacturers' recommendations for specific applications.