Enhancing Sealing Efficiency - Sp Wnd Graphite Ls Gasket

An ASME B16.20 300 lb 304 stainless spiral wound gasket with graphite filler is the springy semi-metallic seal for flanged joints that swing between cold and hot: the stainless winding stores energy while the graphite filler conforms to the faces. It seats alongside our flange gaskets.

What the 300 lb Graphite Spiral Wound Gasket Is

The gasket is built from a 304 stainless strip wound on edge with flexible graphite between the wraps, so the V-profile acts like a spring. The 300 lb class covers the pressure-temperature limits ASME B16.20 sets for that winding and filler combination. Laminated (Ls) builds stack extra graphite layers for softer seating, and inner and outer rings centre the gasket and control compression.

• 304 stainless winding — spring-back strength across thermal cycles.
• Flexible graphite filler — conforms to face serrations and resists high heat.
• 300 lb class per ASME B16.20 — the build's pressure-temperature limits.
• Laminated (Ls) option — extra graphite layers for softer seating on imperfect faces.

Sealing Performance and Temperature Range

The spiral construction recovers as the joint heats and cools, which keeps the seal stable from cryogenic service to several hundred degrees. Graphite filler tolerates steam, hydrocarbons and many chemicals and does not melt or flow like thermoplastic fillers. Bolt load spreads through the winding, so moderate flange irregularities — slight warp or face wear — are absorbed instead of leaking.

Key Benefits

• Sealing from cryogenic duty to high-temperature service.
• Spring-back reduces leak risk through thermal cycling.
• Graphite filler suits steam, hydrocarbons and many chemicals.
• Standard ASME B16.20 dimensions interchange across compliant flanges.

Where They Are Used

These gaskets seal wellheads, pipelines, valves and pressure vessels in oil and gas, plus boilers, heat exchangers and reactors in power and chemical plants. The 300 lb range covers station headers and equipment flanges where temperature swings are routine.

In the Joint

The gasket sits centred between the faces and the bolts squeeze the winding until the graphite fills the serrations; the pipe flanges carry the pipe and the bolt load. Torque evenly in a cross pattern, and never fit a spiral wound gasket on a damaged face.

Installation and Care

Inspect and clean the faces, place the gasket centred in the bolt circle, and bring the bolts up in stages and cross-pattern to the specified torque. Do not over-compress — the outer ring is a stop. At turnaround, check for wind-up, graphite loss and corrosion, and replace the gasket whenever the joint has been opened.

Frequently Asked Questions

Graphite filler versus PTFE filler?

Graphite handles higher temperatures, steam and hydrocarbons and recovers well under cycling. PTFE suits strong chemicals and clean service but creeps more at heat. Match the filler to the media and temperature.

What does the 300 lb class mean?

It is the ASME B16.20 pressure class for the gasket build — the allowed pressure falls as temperature rises, per the standard's rating table.

Can a spiral wound gasket be reused?

No — once compressed and removed, the winding has taken a set and the graphite has thinned. Fit a new gasket at every reassembly.