Spiral Wound Gasket

Spiral Wound Gasket Product Overview

The Spiral Wound Gasket is a flange sealing component designed for industrial piping, valves, pressure vessels, heat exchangers, pumps, and process instrumentation systems.

It is manufactured by spirally winding a pre-formed metal strip together with a soft sealing filler, such as flexible graphite, PTFE, mica, or other materials. This structure gives the gasket both mechanical strength and elastic recovery, making it suitable for demanding applications involving pressure fluctuation, temperature cycling, vibration, and flange load changes.

Spiral wound gaskets are widely used in oil and gas, chemical processing, petrochemical plants, power generation, water treatment, steam systems, and industrial pressure measurement applications.

Product Description

A spiral wound gasket is mainly used to seal the gap between two flange faces. The metal winding provides structural strength and compression recovery, while the filler material helps create the sealing layer against the flange surface.

Compared with flat rubber or PTFE gaskets, spiral wound gaskets are more suitable for industrial applications where the sealing point may experience:

• higher pressure
• higher temperature
• thermal expansion and contraction
• vibration
• flange stress changes
• steam, oil, gas, or chemical media

For many industrial flange connections, especially raised face flanges, a spiral wound gasket with an outer centering ring or inner and outer rings is commonly selected. The outer ring helps position the gasket during installation, while the inner ring helps protect the sealing element from media erosion and over-compression.

Structure Options

Basic Type Spiral Wound Gasket

The basic type consists of only the spiral wound sealing element. It is usually used in special flange grooves or applications where the gasket is positioned by the flange design.

Spiral Wound Gasket with Outer Ring

This type includes an outer centering ring, which helps position the gasket on raised face flanges and prevents over-compression during bolt tightening.

Spiral Wound Gasket with Inner Ring

The inner ring helps reduce turbulence, prevent inward buckling, and protect the sealing element from direct media erosion.

Spiral Wound Gasket with Inner and Outer Ring

This is one of the most commonly used types for industrial flange sealing. It provides better installation positioning, improved sealing stability, and better protection for the winding element.

Key Features

Metal and Soft Filler Wound Structure

The combination of metal strip and soft filler provides both strength and sealing flexibility.

Excellent Recovery Performance

The spiral wound structure allows the gasket to recover under compression changes, helping maintain sealing performance during temperature and pressure cycling.

Suitable for High Temperature and Pressure

Depending on the selected metal and filler materials, spiral wound gaskets can be used in demanding industrial pressure and temperature conditions.

Good Flange Sealing Reliability

Suitable for pipe flanges, valve flanges, equipment flanges, pressure vessel nozzles, and instrument diaphragm seal connections.

Multiple Material Combinations

Common winding materials include SS304, SS316, SS316L, 321, 310S, and other alloys. Common fillers include flexible graphite, PTFE, mica, and ceramic fiber.

Optional Inner and Outer Rings

Inner rings and outer centering rings can be selected according to flange type, pressure class, medium, and installation requirement.

Technical Specifications

Applications

Industrial Pipeline Flanges

Used between pipe flanges to seal water, steam, oil, gas, chemical fluids, and other compatible media.

Valves and Equipment Connections

Suitable for installation between valves, pumps, heat exchangers, pressure vessels, reactors, and process equipment.

Flanged Pressure Transmitters

Used as the sealing gasket between the process flange and the diaphragm seal flange of a flanged pressure transmitter.

Differential Pressure Level Transmitters

Commonly used with single flange and dual flange differential pressure level transmitters for tank and vessel level measurement.

Flushing Rings

When a flushing ring is installed between the process flange and the diaphragm seal flange, spiral wound gaskets are often required on both sides of the flushing ring to ensure reliable sealing.

Typical installation:

Process Flange → Spiral Wound Gasket → Flushing Ring → Spiral Wound Gasket → Diaphragm Seal Flange

Chemical and Petrochemical Processes

Used in chemical pipelines, reactors, storage tanks, process vessels, and equipment nozzles where reliable flange sealing is required.

Steam and High-Temperature Systems

Graphite-filled spiral wound gaskets are commonly used in steam lines, hot oil systems, boiler auxiliary lines, and other high-temperature applications.

Advantages

• Reliable flange sealing for pipelines, valves, equipment, and pressure instruments.
• Metal winding structure provides strength and compression recovery.
• Flexible filler material helps improve sealing performance.
• Suitable for pressure and temperature cycling in industrial process systems.
• Commonly used with flanged pressure transmitters and DP level transmitters.
• Works with flushing rings, mating flanges, diaphragm seals, and flanged pipe fittings.
• Inner and outer ring options improve positioning and sealing stability.
• Multiple material combinations are available for different media and temperatures.
• Custom sizes and standards can be supplied according to project requirements.

Selection Notes

When selecting a spiral wound gasket, confirm the following details:

1. Flange standard and size
   Confirm whether the flange is ASME, EN, DIN, JIS, GB, or another standard, and confirm the nominal size.
2. Pressure class
   Confirm the flange pressure rating, such as Class 150, Class 300, PN16, PN25, PN40, etc.
3. Flange face type
   Confirm whether the flange face is RF, FF, RTJ, tongue and groove, or male and female.
4. Winding material
   Select SS304, SS316, SS316L, or special alloy according to the medium and corrosion requirement.
5. Filler material
   • Flexible graphite: suitable for many high-temperature steam, oil, gas, and chemical applications.
   • PTFE: suitable for many corrosive chemicals but with lower temperature capability than graphite.
   • Mica or ceramic fiber: used for higher temperature applications depending on design.
6. Inner and outer ring requirement
   For common raised face flanges, an outer ring or inner and outer ring structure is usually preferred for easier positioning and safer installation.
7. Instrument application
   If used with a pressure transmitter, diaphragm seal, or flushing ring, confirm flange size, sealing face, gasket thickness, bolt length, and process temperature.
8. Medium characteristics
   Confirm whether the medium is steam, water, oil, gas, acid, alkali, solvent, slurry, or corrosive chemical before selecting material.