These ISO DN 63 one sided centering rings are made with inner and outer rings of Stainless Steel with durable Viton® (FPM) rubber, elastomeric, O-rings and are used to seal both ISO-K and ISO-F vacuum flanges when joint together. These ISO 63 one sided centering rings are commonly used to build process vacuum plumbing and systems for industrial standard and high vacuum applications.

The ISO flanges principle is to joint two ISO-K or ISO-F flanges together, with a centering ring in between them to form the vacuum seal, using bolts or clamps. The centering ring prevents the O-ring being pushed in by the external atmospheric pressure when the joint is under vacuum. The one-sided centering ring has one flat side to use on the ISO-F flange, while the opposite side with the centering ring, faces the ISO-K flange helping to align the flanges. (See the connection image to the left). In this specific connection method, the ISO-K (K-style) flange, uses separate clamps that are hooked over the outer edge of the mating flanges and spaced around the circumference. The second flange, ISO-F (F-style), uses conventional bolt holes in the flange periphery to use on through holes or tapped holes.

ISO-K fittings are quick to assemble using claw clamps (please see figure - click to enlarge) and can be connected 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 63 one sided 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 Stainless Steel with FPM rubber O-ring material. These centering rings follow vacuum technology standards as described in DIN 28404 and ISO 1609.