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ISO to KF Flange Adaptors

ISO KF Vacuum Fitting and Component System


ISO-KF vacuum fitting components form a modular system for piping from 3/4 to 4 inches (16 to 100 mm). The MKS ISO-KF vacuum fitting system allows the building of high vacuum systems quickly, without welding or brazing. Modification of vacuum systems built with ISO-KF vacuum fittings is quick and easy.


ISO-KF fittings can be used in a wide variety of applications including:

Roughing and foreline plumbing
Small systems
Systems requiring frequent cleaning or modification
Research and teaching laboratories.


ISO-KF vacuum fittings are primarily designed for use at subatmospheric pressure. Because of the large number of elastomer seals used, typical limiting pressure without baking is about 10-7 Torr. Baked systems using Viton® seals can be used to two decades lower.

Standard components can be used to slight overpressure. If the ISO-KF system contains significant overpressure, i.e., 5-100 psig, then use MKS overpressure rings.

The ISO-KF vacuum component system is a modular, building block method of creating a piping system. There are several advantages in the use of ISO KF vacuum fittings. Since ISO KF vacuum component dimensions are standardized, elbows, tees, crosses or valves for A given size may be interchanged. MKS ISO-KF flanges are "sexless" and the seal is symmetrical, making MKS ISO KF components rotatable. By using ISO KF vacuum fittings, vacuum component assembly is quick and cost effective.