Spiral Wound Gasket

WHAT IS A SPIRAL WOUND GASKET?

A Spiral Wound Gasket (SWG) is one of the most widely used semi-metallic sealing solutions in industrial applications. It is engineered by winding a metallic strip together with a soft filler material to create a resilient and highly effective sealing element.

Spiral wound gaskets are designed to maintain sealing integrity under high temperature, high pressure, thermal cycling, vibration, and flange movement. When correctly selected and installed, they deliver long service life and minimize leakage in critical process systems.

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STRUCTURE OF SPIRAL WOUND GASKET

A Spiral Wound Gasket generally consists of three main components:

1. Outer Ring (Centering Ring)

The outer ring is commonly manufactured from carbon steel or stainless steel.

Functions:

• Centers the gasket during installation

• Controls gasket compression

• Protects the sealing element from excessive loading

• Improves sealing stability

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2. Inner Ring

The inner ring is typically manufactured from stainless steel.

Functions:

• Prevents inward buckling of the sealing element

• Protects against flow turbulence

• Minimizes flange erosion

• Reduces contamination entering the process stream

• Enhances gasket rigidity and operational safety

Inner rings are highly recommended in high-temperature and high-pressure applications.

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3. Sealing Element

The sealing element consists of:

• Metallic winding strip

• Soft filler material

Common winding materials:

• Stainless Steel 304

• Stainless Steel 316

• Stainless Steel 321

• Stainless Steel 347

• Monel

• Inconel

• Titanium

• Hastelloy

Common filler materials:

• Flexible Graphite

• PTFE (Polytetrafluoroethylene)

• Mica

• Ceramic

Flexible graphite is widely selected for refinery and high-temperature services due to its superior thermal stability.

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INSTALLATION GUIDE FOR METALLIC GASKETS

Proper installation is essential to achieve optimum gasket performance.

Installation recommendations:

• Clean flange surfaces before assembly

• Verify gasket dimensions and compatibility

• Position the gasket accurately between flange faces

• Tighten bolts using a controlled cross-pattern sequence

• Apply uniform bolt load to avoid uneven compression

• Re-torque when required by operating procedures

Proper installation helps ensure:

• Initial sealing performance

• Long-term sealing reliability

• Easy maintenance and replacement

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TYPES OF SPIRAL WOUND GASKETS

Spiral Wound Gasket Without Rings (Basic Type)

Construction:

• Sealing element only

Features:

• Flexible sealing performance

• Suitable for tongue and groove flanges

• Suitable for male and female flanges

Applications:

• Moderate service conditions

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Spiral Wound Gasket With Outer Ring (CG Type)

Construction:

• Sealing element + outer ring

Features:

• Prevents over-compression

• Simplifies installation

• Improves gasket alignment

Applications:

• Raised face flanges

• Flat face flanges

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Spiral Wound Gasket With Inner Ring (CGI Type)

Construction:

• Sealing element + inner ring

Features:

• Prevents internal buckling

• Reduces process turbulence

• Protects process equipment

Applications:

• Male and female flange systems

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Spiral Wound Gasket With Inner & Outer Ring

Construction:

• Sealing element + inner ring + outer ring

Features:

• Maximum sealing efficiency

• Excellent structural stability

• Enhanced pressure resistance

Applications:

• Severe operating conditions

• High-pressure industrial systems

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MATERIAL IDENTIFICATION – SPIRAL WOUND GASKET COLOR CODES

Outer Ring Color → Metallic Material

• Yellow → SS304

• Green → SS316

• Turquoise → SS321

• Blue → SS347

• Orange → Monel

• Black → Alloy 20

• Silver → Carbon Steel

• Brown → Hastelloy B

• Beige → Hastelloy C

• Gold → Inconel

• Red → Nickel

• Purple → Titanium

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Stripe Color → Filler Material

• Gray → Graphite

• White → PTFE

• Pink → Mica

• Light Green → Ceramic

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HOW TO CHOOSE A SPIRAL WOUND GASKET

Selection factors:

• Operating temperature

• System pressure

• Chemical compatibility

• Flange type

• Media characteristics

• Required service life

• Applicable industrial standards

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THICKNESS OF SPIRAL WOUND GASKET

Typical thickness ranges:

• 3.2 mm (1/8")

• 4.5 mm (3/16")

• Customized dimensions available upon request

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KEY FEATURES OF SPIRAL WOUND GASKET

• Excellent sealing performance

• Suitable for high temperature and pressure

• Superior compression recovery

• Resistant to vibration and thermal cycling

• Compatible with aggressive process media

• Excellent mechanical strength

• Long operational lifespan

• Suitable for vacuum and high-pressure systems

Typical operating range:

• Temperature: -200°C to +700°C (depends on material)

• Pressure: Vacuum to 25 MPa (depends on design and standard)

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APPLICATIONS OF SPIRAL WOUND GASKET

• Oil & Gas Industry

• Refineries

• Petrochemical Plants

• Chemical Processing

• Steam Systems

• Power Generation

• Heat Exchangers

• Pumps and Valves

• Industrial Piping Systems

• Process Equipment