Spiral Wound Gasket

A spiral wound gasket is a semi-metallic sealing element designed for demanding flange applications where conventional soft gaskets are insufficient. It combines the resilience of metallic winding strips with the conformability of a soft filler material, delivering reliable sealing performance across a wide range of pressures and temperatures.

Construction

The sealing element is formed by alternating V-shaped metallic winding strips — manufactured from stainless steel SS 304 or SS 316 — with layers of soft filler material, either flexible graphite or PTFE. This alternating construction creates a spring-like structure that maintains seating stress under thermal cycling and pressure fluctuations.

An outer carbon steel (CS) retaining ring provides radial support, prevents over-compression of the winding, and acts as a centering guide during installation. An inner carbon steel centering ring reinforces the bore side of the gasket, preventing inward buckling of the winding and minimising turbulence at the pipe bore.

Standards and Pressure Classes

These gaskets are manufactured in full compliance with ASME B16.20, covering spiral wound metallic gaskets for pipe flanges. They are available across the full ASME pressure class range from Class 150 through Class 2500, accommodating both low-pressure utility services and extreme high-pressure process applications.

Temperature Capability

With a graphite filler, the gasket is rated for continuous service up to 650°C, making it suitable for high-temperature steam, hot oil, and process gas services. PTFE-filled variants offer excellent chemical resistance and are preferred for corrosive media at moderate temperatures.

Typical Applications

Spiral wound gaskets are widely specified for flanged pipe joints across critical industries:

• Oil & gas — wellhead, pipeline, and refinery process flanges
• Petrochemical — reactor, heat exchanger, and column flanges
• Power generation — steam turbine, boiler, and high-pressure steam line flanges
• Chemical processing — aggressive media services requiring chemical-resistant PTFE filler