Marco Rubber & Plastics

• Back-Up Rings used with O-Rings at pressures > 1500 psi or big extrusion gaps
• Back-Up Rings are designed to limit O-Ring clearance gap extrusion.
• Available in elastomeric compounds and PTFE Back-Up Rings.
• PTFE Back-up rings can be solid, split, spiral, or custom for ease of install.
• PTFE Back-up Ring size standards AN6244, AN6246, MS27595, MS28774, MS28782 and MS28783.
• Elastomer Back-up Rings are typically contoured to conform to an O-Ring.
• Elastomer Back-up Rings fit standard USA and custom O-Ring sizes.
• Back-up Rings require wider glands to accommodate.

Back-up Rings are flat, split, spiral or contoured washer type fittings used to protect an O-Ring seal from extrusion at higher pressures and temperatures. A Back-up Ring works by blocking or reducing the extrusion gap, thus preventing the o-ring from extruding. The use of a back-up ring increases the pressure and temperature capability of o-rings. Back-up Rings can be solid, split, spiral or contoured. The split and spiral back-up rings are easier to install, especially in small diameters. The chart to the right depicts the higher pressure capabilities of using Back-up Rings for a given clearance gap dimension. Back-up Rings can be used on both sides of the O-Ring if pressure is bidirectional. Gland widths should be widened to accommodate one or two Back-up Rings. Please contact us for selection and design assistance.