These ISO DN 500 centering rings are made of aluminum with Neoprene (CR) rubber, also called polychloroprene or chloroprene, O-rings and are used to seal both ISO-K and ISO-F vacuum flanges. Neoprene offers moderate resistance to oils and petroleum products, but provides significantly greater resistance to sunlight, ozone, and weather. Neoprene provides very good-to-excellent resistance against the spread of flame. Minimum Service Temperature -30° F to -70° F; Maximum Service Temperature +220° F to +280° F. Generally Resistant to Moderate chemicals and acids, ozone, oils, fats, greases, and solvents.

Neoprene rubber resists fire and withstands sunlight, ozone, and weather. Specific grades of neoprene can also meet flame, smoke and toxicity (FST) requirements for the mass transit industry. Applications include door seals, window seals, hose covers, vibration mounts, and shock absorbers. Neoprene is also used with HVAC units, electrical or electronic enclosures, and weather stripping for fire doors. Additional applications include expansion joints and bearing pads in built structures.

These centering rings follow vacuum technology standards as described in DIN 28404 and ISO 1609. The centering ring which contains a rubber elastomeric O-ring forms the vacuum seal between the two mating ISO-K or ISO-F flange faces. ISO-K fittings are quick to assemble using claw clamps (please see figure - click to enlarge) and can be connected together in any orientation. The claw clamp hooks into a ridged groove in the back side of the ISO-K flange. ISO-F fixed flange vacuum fittings are different and have a bolt circle where bolts align the two flanges. These ISO 500 centering rings are commonly used to build process vacuum plumbing and systems for industrial standard and high vacuum applications. The ISO standard sizes for large LF flanges are ISO-F and ISO-K DN 63, 80, 100, 160, 200, 250, 320, 400, 500, 630, 800, 1000. These vacuum fittings are made with inner and outer rings of Aluminum 6082 with Chloroprene (CR) rubber O-ring material.