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ISO flanges in vacuum systems

ISO flanges in vacuum systems

Nov. 02, 2022

What is an ISO flange? ISO flanges are subdivided into ISO-K and ISO-F. What are the differences and connections between them? This article will take you through these questions.


ISO is an accessory used in high vacuum systems. The construction of ISO flange series includes two smooth-faced sexless flanges clamped together with a combination metal centering ring and elastomeric O-ring between them.


     Compared to the vacuum seals of the KF series, ISO series seal is consisit of central support and Viton ring, there is also an additional aluminium spring-loaded outer ring. The main function is to prevent the seal from slipping out of place. Because of the relatively large pipe size of the ISO series The seal is placed on the centre support and is subject to machine vibration or temperature. If the seal is not secured, it will slip out of place and affect the seal.


The two types of ISO flanges are ISO-K and ISO-F. Which are large size vacuum couplings that which can be used where vacuum levels of up to 10-8 mbar are required. Flange sealing materials are usually Viton, Buna, Silicone, EPDM, aluminium, etc. Flanges are usually made of 304, 316 stainless steel, etc.


ISO-K vacuum couplings usually consist of a flange, a clamp, an O-Ring and a centering ring.

ISO-F vacuum couplings usually consist of a flange, an O-Ring and a centreing ring, which differs from ISO-K in that the flange is bolted.