Inner and Outer Ring of SWG
Model:KXT-R640
We Inner Outer Ring Of SWG make different inner and outer rings small than 14 inch.Large sizes also can be.
Model KXT-R640
Inner & Outer Ring Spiral Wound Gaskets — The CGI Construction Explained
The inner and outer ring construction is the most widely specified spiral wound gasket for raised-face and flat-face flanges. The outer ring centres the gasket and stops over-compression; the inner ring prevents inward buckling, reduces turbulence and protects the flange bore from erosion. Together they give the highest sealing safety in the spiral wound gasket family.
Available in sizes up to and beyond 14", in SS304, SS316, SS321, Monel, Inconel and more, with graphite, PTFE, non-asbestos or mica filler. Made to ASME B16.20 / EN 1514-2 / API 601. Send your flange size, media, pressure and temperature — technical recommendation and quotation within 2 business hours.
A spiral wound gasket with inner and outer rings (CGI type) combines a V-shaped metal winding, an inner metal ring and an outer centring ring in one assembly. It fits RF and FF flanges, prevents winding collapse, and protects the flange bore from turbulence. Sizes from DN15 to DN600+ (up to and beyond 14"), Class 150 to 2500. EN 10204 3.1 certificates available on request.
What the Inner and Outer Rings Actually Do
Buyers often ask why a spiral wound gasket needs two rings when one seems to be enough. The answer is that the two rings solve two completely different problems:
The V-shaped stainless strip and filler carry the actual sealing load. It acts as a spring — compressing and rebounding under pressure and temperature cycling.
Sealing elementFills the gap between the flange bore and the gasket ID. Prevents the winding from buckling inward under pressure, reduces turbulence, shields the flange face from erosion and corrosion.
Anti-buckling · anti-erosionSits on the bolt circle, centres the gasket on the flange, and acts as a compression stop so the winding cannot be crushed by over-bolting.
Centring · compression stop
Inner Ring vs Outer Ring — What Each One Solves
If you are deciding between the CG (outer ring only), IR (inner ring only) or CGI (both rings) construction, the table below shows exactly which problem each ring solves. Most projects end up with CGI because the cost difference over CG is small and the reliability gain is significant.
Inner Ring Solves: erosion, buckling, corrosion
What it protects against
- Inward buckling of the winding under pressure
- Turbulence and erosion at the flange bore
- Corrosion of the flange faces in the annular space
- Accumulation of solids between flange bore and gasket ID
When it is essential
- High vacuum service
- High flow velocity lines
- Media that causes turbulence or erosion
- Cyclic pressure / temperature service
See also our CGI full product page.
Outer Ring Solves: centring, over-compression
What it protects against
- Off-centre seating of the gasket on the bolt circle
- Over-compression and crushing of the winding
- Unwinding or distortion during handling and installation
- Movement of the gasket under vibration
When it is essential
- All raised-face and flat-face flanges
- Any line where bolts may be over-torqued
- High vibration service (pumps, compressors)
- Any joint where centring accuracy matters
See also our CG outer ring only product page.
R / IR / CG / CGI — Pick the Right Construction
All four constructions use the same winding and filler technology; the difference is which rings are present. The table below is a starting point for procurement discussions. If you tell us the line conditions, we will confirm which one fits.
| Construction | Rings | Best Suited For | Typical Applications |
|---|---|---|---|
| Basic R | None | Tongue-and-groove, male-and-female, confined joints | Valve bonnets, boiler handholes, pump casing covers |
| IR | Inner ring only | M&F flanges, high vacuum, erosion-prone service | Heat exchangers, vacuum columns |
| CG | Outer ring only | RF and FF flanges, general purpose | Steam, water, oil, utility piping |
| CGI | Inner + outer ring | Class 900+, high vacuum, cyclic service, critical joints | Refinery, petrochemical, power plants, heat exchangers |
Not sure which one you need? Send us the flange standard, media, pressure and temperature. We will recommend the construction, the winding metal and the filler — and we will say so honestly if the cheaper option will do the job.
What Buyers Get From Kaxite
Direct factory pricing
We wind, weld, size and inspect every gasket in our own workshop. No trading company mark-up. See our workshop.
Sizes up to and beyond 14"
Standard sizes up to 14" from stock tooling. Larger diameters and non-standard bolt circles produced to drawing — no size limit in practice.
Material matched to media
SS304, SS316, SS321, Monel, Inconel, Hastelloy and more — see special materials.
Certificates with the goods
EN 10204 3.1 material certificates on request. Heat number traceable to the incoming strip. See our certificates.
2-hour technical reply
Our technical sales team reviews your media, pressure and temperature and replies with a recommendation — not just a price.
Export-ready packing
Plastic film protection inside wooden pallets or cases, suitable for sea and air freight. See packaging & shipping.
Winding Metal and Filler Options
Winding metal
- SS 304 / 304L
- SS 316 / 316L
- SS 321
- SS 347
- SS 309
- SS 310
- SS 317L
- SS 904L
- Monel 400
- Inconel 600 / 625 / 800 / 825
- Hastelloy B3 / C276
- Titanium Gr.2
Filler material
- Flexible Graphite
- PTFE
- Non-Asbestos
- Mica
Inner and outer ring material
- Carbon steel (zinc plated)
- Carbon steel (painted)
- SS 304
- SS 316
- SS 316L
Standard supply is SS316 winding with graphite filler and a carbon steel zinc-plated outer ring — the most cost-effective combination for steam, water, oil and general chemical service. The inner ring is usually matched to the winding metal to avoid galvanic corrosion in the bore.
Technical Specifications
Typical Applications
- High temperature and high pressure equipment
- Extreme low temperature and cryogenic service
- M&F and special flanges requiring confined gaskets
- Heat exchangers and condensers — see our heat exchanger spiral wound gaskets
- Boiler manholes and handholes
- Pump and valve covers, turbine casings
- Refinery, petrochemical and power plant piping
Related product ranges in the same family: all spiral wound gaskets, standard spiral wound gasket (KXT-600), CG outer-ring version, oval and oblong gaskets for boilers, ring joint gaskets and expanded graphite gaskets.
Why the CGI Construction Is Worth the Extra Cost
- Longer service life. The inner ring eliminates the erosion and corrosion damage that shortens the life of a CG gasket in aggressive or high-velocity service.
- Higher pressure capability. The inner ring acts as a compression stop on the inside of the winding, allowing the gasket to be used in Class 900 and above.
- Safer installation. Both rings keep the winding intact during handling and prevent deformation from over-bolting.
- Lower long-term cost. The incremental cost of the inner ring is small compared to the cost of an unscheduled shutdown to replace a failed gasket.
- Wide material choice. Both rings and the winding can be matched to the medium — see special materials.
- Fully traceable. Heat-number marking on the outer ring and EN 10204 3.1 certificates on request. See our certificates.
Packing, Shipping and Identification
Packing
Each spiral wound gasket is protected with plastic film, then packed in wooden pallets or wooden cases suitable for sea and air freight. Customer labels and packing lists are available on request — see packaging & shipping.
Shipping
By sea, by rail or by air, depending on your schedule and destination. Standard materials normally ship within 7–15 working days of order confirmation.
Gasket identification
Every outer ring is stamped with size, pressure class, material code and heat number — the same information that appears on the material certificate, so your maintenance team can verify the gasket on site without opening the line.
Reference: basic type (no rings)
For completeness, the basic R construction — winding only, without inner or outer ring — is shown below. It is used on tongue-and-groove and male-and-female joints where the flange itself centres and confines the gasket. For those who need it, we produce R, IR, CG and CGI on the same equipment.
Ordering Information You Should Prepare
To give you a firm quotation the first time, please include the following in your inquiry:
- Gasket standard and size — ASME B16.20 / EN 1514-2 / API 601, DN or NPS, Class or PN
- Construction — Basic R, IR, CG or CGI (this page covers CGI)
- Winding metal and filler — e.g. SS316 + graphite
- Inner and outer ring material and finish — carbon steel zinc plated, painted, or stainless
- Operating conditions — pressure, temperature, media name and concentration
- Quantity and required delivery date
- Documentation — EN 10204 3.1 certificate, third-party inspection or test reports
Buyer FAQ
What is the difference between CG, CGI and IR spiral wound gaskets?
CG has only an outer centring ring. IR has only an inner ring for anti-erosion and anti-buckling. CGI has both — outer ring for centring and compression stop, inner ring for bore protection. CGI is the most widely specified construction for critical service.
Can I order just the inner ring or the outer ring separately?
Yes. Both rings are fabricated in our own workshop. If you need replacement rings for existing gaskets, send the drawing or dimensions and we will quote them individually.
What is your maximum size?
Standard sizes up to 14". Larger diameters — including sizes beyond 24" — are produced to drawing. In practice, the only limit is the diameter of our winding mandrel, and we have produced gaskets well beyond DN3000.
Can the inner and outer ring materials be different?
Yes. The inner ring is normally matched to the winding metal to avoid galvanic corrosion in the flange bore, while the outer ring can be a lower-cost carbon steel since it does not touch the process fluid.
Do you supply material certificates?
Yes. EN 10204 3.1 certificates are available on request, and third-party inspection (SGS, BV, TUV or client-nominated) can be arranged or hosted at additional cost. See our certificates.
How long does production take?
Standard materials normally ship within 7–15 working days of order confirmation. Custom sizes and exotic winding metals may take longer; we will state a realistic date in the quotation.
What payment terms do you accept?
Normally T/T with a 30% deposit and balance before shipment. L/C at sight can be discussed for larger orders. Terms are confirmed in the quotation.
Request a Quote for Inner & Outer Ring Spiral Wound Gaskets
Send us the flange standard and size, construction (CGI or other), winding metal, filler, inner and outer ring material, media, pressure, temperature and quantity — we will reply with a technical recommendation, price and realistic delivery date within 2 business hours.
- Tel: 0086-574-87527771
- E-mail: kaxite@seal-china.com
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Contact Info
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Address
No. 432 Zhenhai Middle Road, Luotuo Street, Zhenhai District, Ningbo City, Zhejiang China
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Share your sealing requirement and our technical sales team will respond within 24 business hours. For fastest service, include your flange specification, operating pressure, temperature, and process media in the message below.
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