Rubber Gasket Rings

Flat ring gaskets for manways, flanges and equipment covers. Custom ID, OD and thickness in any elastomer.

Overview

Rubber gasket rings are flat annular seals used where a circular sealing area is needed but the geometry does not suit a toroidal O-ring. They seal between two flat surfaces under bolt load, just like full-face gaskets, but only occupy the ring-shaped area required for the joint. This makes them economical for large flanges, manways and equipment covers where a full-face gasket would waste material. The term ring gasket covers two related forms in rubber service: flat rubber rings used on manways and covers, and inner-bolt-circle (IBC) rings used on pipe flanges. Both are defined by inner diameter, outer diameter and thickness. Unlike a round rubber O-ring, a rubber gasket ring does not sit in a groove and is not designed for radial compression; it relies on axial compression between flat faces. Round rubber gasket rings are common on filter housings, pressure vessel manways, pump covers, inspection hatches and valve bonnets. Materials follow the same rules as other flat gaskets: EPDM for water and weather, NBR for oil, VMQ for food and high temperature, CR for outdoor and refrigeration, FKM for chemicals, and PTFE for aggressive media. We cut rubber gasket rings to your ID/OD/thickness or drawing. Standard tolerances are ±0.2–0.5 mm depending on cut method and size. Specify material, hardness, thickness, ID, OD and quantity when requesting a quote.

Types

Flat Ring Gaskets

Solid elastomer ring with rectangular cross-section. Used on manways, covers and equipment housings.

Best for: Filter housings, manways, pump covers, inspection hatches

IBC Pipe Flange Rings

Ring gasket sitting inside the bolt circle of a pipe flange. Bolt holes remain exposed.

Best for: Steel pipe flanges, valve bonnets, pump nozzles

Round Gasket Rings with Lip

Ring with a raised sealing lip or profile for improved compression control.

Best for: Equipment doors, low-bolt-load covers

Materials

Material	Properties	Best For
EPDM	Water, steam, ozone resistant; −50°C to +150°C	Water treatment manways, outdoor covers
NBR	Oil and fuel resistant; −40°C to +120°C	Oil filter housings, hydraulic covers
VMQ Silicone	High temperature, FDA grades; −60°C to +200°C	Food equipment covers, autoclave doors
FKM	Chemical and high-temp resistance; −20°C to +200°C	Chemical reactor manways, hot oil covers

Sizing

Ring gaskets are defined by ID, OD and thickness. Custom sizes from drawing.

Thicknesses

• 1/32"
• 1/16"
• 3/32"
• 1/8"
• 3/16"
• 1/4"
• Custom

Tolerances

• Die-cut ±0.1–0.2 mm
• Waterjet ±0.2–0.5 mm
• Flashcut ±0.1–0.3 mm

Applications

Water Treatment

Filter vessel heads, UV reactor covers, valve bonnets

Food & Beverage

Tank manways, CIP covers, pasteurizer heads

Hydraulics

Reservoir covers, filter bowls, inspection caps

Chemical

Reactor manways, separator covers, sampler ports

Frequently Asked Questions

What is the difference between a rubber gasket ring and an O-ring?

A rubber gasket ring is a flat annular seal compressed between two flat faces. An O-ring is a toroidal seal that sits in a groove and seals by radial or axial compression in a gland. Gasket rings do not require grooves; O-rings do.

Can a rubber O-ring be used as a flat gasket?

Not reliably. An O-ring is designed to deform into a groove. Used flat without a groove it will roll, over-compress locally and leak. Use a flat gasket ring for flat-face joints.

How do I measure a round rubber gasket?

Measure inner diameter, outer diameter and thickness with calipers. For worn samples, measure the groove land and mating surface to determine the correct replacement size.

What is an IBC ring gasket?

IBC stands for inner bolt circle. An IBC ring gasket sits inside the bolt circle of a flange, leaving bolt holes clear. It is common on steel pipe flanges.

Can rubber gasket rings be custom cut?

Yes. We cut custom ID/OD ring gaskets by die-cut, waterjet or flashcut from any of our stocked elastomer sheets.