Spiral Wound Gaskets
Spiral wound gaskets are semi-metallic sealing elements engineered for high-pressure, high-temperature, and chemically aggressive applications. Combining a spirally wound stainless steel strip with a soft filler material, they provide excellent sealing performance, flexibility, and recovery under fluctuating operating conditions.
Overview
Spiral wound gaskets are semi-metallic gaskets consisting of a V-shaped metallic strip spirally wound with a non-metallic filler material. This construction provides a unique combination of strength, flexibility, and resilience, making them ideal for demanding sealing applications.
Design & Construction
- Spirally wound V-shaped stainless steel strip
- Soft filler material such as flexible graphite or PTFE
- Solid outer centering ring to control compression and ensure correct positioning
- Optional inner ring for bore protection and enhanced stability
Operating Principle
The metallic winding provides structural strength and resilience, while the filler material ensures tight sealing by conforming to flange surface irregularities. This combination allows the gasket to maintain sealing integrity under fluctuating pressure, temperature changes, and bolt load relaxation.
Materials
- Metal Strip: Stainless Steel (SS 304, SS 316L, SS 321), Carbon Steel, or other alloys
- Filler Material: Flexible Graphite, PTFE, Mica (application dependent)
- Outer Ring: Carbon Steel or Stainless Steel
Key Performance Characteristics
- Excellent sealing under high pressure and temperature
- High recovery and resilience during thermal cycling
- Resistance to chemical attack depending on filler and metal selection
- Capable of compensating for flange surface imperfections
Historical Background
Spiral wound gaskets were developed in the early 20th century to meet the increasingly severe operating conditions encountered in oil refinery and petrochemical applications, where conventional soft gaskets were unable to perform reliably.
Standards
- ASME B16.20
- EN 1514-2
- EN 12560-2
Applications
- Oil and gas industry
- Petrochemical and chemical processing plants
- Refineries
- Power generation facilities
- Heat exchangers
- Compressors, pumps, and pressure vessels
Advantages
- Superior sealing performance under extreme conditions
- Excellent recovery from pressure and temperature fluctuations
- Wide material selection for various media compatibility
- Long service life with proper installation
- Suitable for raised-face and tongue-and-groove flanges
Important Notes
- Proper bolt loading is essential for optimal sealing
- Material selection should match operating pressure, temperature, and chemical environment
- Recommended for applications where gasket recovery is critical