Spiral Wound

Description:

A spiral wound gasket is a semi-metallic sealing device made by winding alternating layers of a metal strip (usually stainless steel) and a soft filler material (such as graphite or PTFE) into a spiral shape. This construction combines the resilience of metal with the sealing ability of soft filler, making it suitable for sealing flanged joints under demanding conditions of pressure and temperature.

Category:

Working Principle: The mechanism relies on a composite structure and controlled compressibility:

  1. Metal Winding (Outer/Inner Rings)
    • A preformed metal strip is wound into a V-shaped or hoop-shaped profile.
    • Provides mechanical strength, resilience, and shape retention.
    • Acts as a spring, maintaining sealing force even under fluctuating loads.
  2. Filler Material
    • A soft, compressible material (graphite, PTFE, or ceramic) is wound alternately with the metal strip.
    • Fills microscopic irregularities on the flange surface.
    • Provides the primary sealing barrier against leakage.
  3. Compression and Recovery
    • When bolted between two flanges, the gasket compresses under load.
    • The metal winding allows it to flex and recover slightly with pressure or temperature changes, maintaining a tight seal even during thermal cycling or vibration.
  4. Centering/Guide Rings
    • Inner and outer rings help with alignment, prevent blowout, and protect the windings from damage during installation.

Primary Use: The primary use of a spiral wound gasket is to provide a reliable, leak-tight seal between flanged connections in high-pressure and high-temperature systems, while accommodating thermal expansion, vibration, and pressure fluctuations.

Common Applications: Spiral wound gaskets are widely used in:

  • Oil and gas refineries and pipelines
  • Petrochemical and chemical processing plants
  • Power generation plants (steam and turbine systems)
  • Heat exchangers and pressure vessels
  • High-pressure steam and hot water systems
  • Marine and offshore platforms
  • Aerospace and defense equipment
  • Flanged pipe joints requiring critical sealing performance