The R31 Series Star Seal also known as the R-Ring or Octagonal Seal is a premium double-acting reciprocating and static sealing solution engineered for severe industrial environments. Moving beyond traditional O-rings and X-rings, its unique symmetric octagonal cross-section profile delivers precise initial pre-compression and excellent fluid-dynamic self-tightening under high pressure.

To withstand aggressive chemical media, extreme temperatures, and heavy friction, the R31 is available in specialized high-performance elastomers and engineering plastics:

• FFKM Perfluoroelastomer: Universal chemical resistance and thermal stability up to +325 degrees Celsius. Ideal for semiconductor etch processes and aerospace fuels.
• FKM Viton: Superior resistance to high temperatures (-20 to +200 degrees Celsius), oils, ozone, and aging. Standard for automotive and oil and gas.
• HNBR Hydrogenated Nitrile: Exceptional tensile strength, wear resistance, and H2S sour gas durability. Rated up to +150 degrees Celsius.
• PTFE Filled Grades: Ultra-low friction coefficient. Eliminates stick-slip/crawling issues in high-speed or ultra-low-speed servo cylinders.
• UHMWPE: Unrivaled abrasion resistance against abrasive solid particles and slurries.

Anti-Spiral Failure: The wide, flat base of the octagonal profile provides high mechanical resistance against twisting inside the groove, completely preventing spiral roll-over during long-stroke reciprocating movements.

Low Friction and No Stick-Slip: At zero pressure, the multi-faceted profile creates narrow, concentrated linear contact zones rather than large surface contact, reducing startup and dynamic friction by over 30 percent.

Pressure-Activated Self-Tightening: When fluid pressure increases, the geometry naturally expands the sealing lips, ensuring reliable sealing and high extrusion resistance at pressures exceeding 40 MPa.

Integrated Lubrication Pockets: The symmetric concave indentations act as micro-reservoirs that trap lubricant during the stroke, ensuring continuous oil-film retention and extending service life.

High-Pressure Hydraulic and Pneumatic Cylinders: Heavy-duty construction machinery, hydraulic supports, and high-frequency servo actuators.

Precision Metering and Dispensing Systems: Polymer metering gear pumps, chemical dosing systems, and premium hot-melt adhesive equipment such as aftermarket Nordson systems.

Semiconductor and Vacuum Chambers: High-purity FFKM R31 seals for plasma etch chambers and vacuum isolation doors.

Oil and Gas Subsurface Tools: Downhole safety valves (DHSV), Christmas trees, and MWD/LWD drilling tools handling high-pressure, high-temperature (HPHT) multi-phase flows.