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Custom Spiral Wound Gaskets: Specification and RFQ Guide
Quick Answer: CORASEALS supplies custom spiral wound gaskets to match flange dimensions, pressure class, service temperature, and fluid. Send the flange standard, gasket ID × OD × thickness, metal strip material, filler material, and operating conditions for a quote. Confirm the gasket seating surface and pressure class before finalizing dimensions.
What Is a Custom Spiral Wound Gasket
A spiral wound gasket is a semi-metallic flange gasket made from alternating layers of a formed metal strip and a softer filler material. The sealing element is wound in a spiral shape. The metal strip provides strength and resilience. The filler conforms to flange surface irregularities and blocks leakage. A custom spiral wound gasket means the ID, OD, thickness, metal strip, filler, outer ring, and inner ring are selected for a specific flange and service condition.
Standard spiral wound gaskets fit common ASME pipe flanges. Custom gaskets are used when the flange is non-standard, the sealing area is narrow, the temperature or pressure is outside common ranges, or the plant specification requires a specific material combination. CORASEALS supplies custom spiral wound gaskets within its flange gasket product range.
Data Required for Custom Spiral Wound Gaskets
The inquiry data below prevents dimensional errors and material mismatch. State whether dimensions are in millimeters or inches.
- Flange standard: ASME B16.5, EN 1092, JIS, or customer drawing.
- Pressure class: class 150, class 300, class 400, class 600, class 900, class 1500, or class 2500.
- Pipe size: NPS, DN, or actual pipe outside diameter.
- Gasket dimensions: ID × OD × thickness, or ID × OD × winding thickness.
- Seating surface: raised face, flat face, male and female, or tongue and groove.
- Metal strip material: 304, 316L, 321, Inconel, or another alloy.
- Filler material: graphite, PTFE, or another filler approved for the fluid.
- Ring construction: outer ring, inner ring, or both.
- Service conditions: operating pressure, operating temperature, medium, and flange material.
- Quantity, drawing, sample photo, or existing gasket code.
The gasket ID must clear the pipe bore and match the flange seating surface. The OD must fit inside the bolt circle without covering bolt holes. If the gasket has an inner ring, confirm the inner ring ID and material. The inner ring prevents windings from buckling into the bore and protects the sealing element from flow erosion.
Metal Strip and Filler Selection
The metal strip resists crushing, blowout, and temperature. Common choices are stainless steel 304, 316L, 321, and Inconel. The filler creates the primary seal. Graphite filler is common in steam, high temperature hydrocarbon, and general chemical flange service. PTFE filler is selected for strong acids, oxidizing media, or services where graphite cannot be used. The final material selection depends on the actual fluid composition, temperature, pressure, and plant specification.
CORASEALS does not assign fixed temperature limits to a material combination without a full service review. Temperature limits change with filler type, metal grade, gasket thickness, flange design, and bolt load. Send the operating data for a confirmed material recommendation.
Outer Ring and Inner Ring
An outer ring centers the gasket on the flange and limits over compression. An inner ring protects the sealing element and prevents inward buckling. Many ASME B16.20 gaskets use an outer ring and inner ring for raised face flanges. For tongue and groove or male and female joints, the ring construction can be different. Some flange designs allow a spiral wound gasket without rings. Confirm the flange type before selecting that construction.