3.3.2 Detachable flange connections
The individual components of a vacuum system, e.g. vacuum chambers, pumps, valves, measurement instruments, etc., are connected with one another either directly or by means of pipe components or resilient elements. The detachable interfaces between the components must be vacuum-tight. In configuring a vacuum system, however, as few detachable joints as possible should be used, as they represent a significantly more frequent source of potential leakage than non-detachable joints.
Flange components from stainless steel, aluminum and steel can be used as connection elements. Metal hoses made of stainless steel are preferable to thick-walled rubber or thermoplastics for flexible joints. They are a strict necessity from the lower medium vacuum range onward.
From low to high vacuum ranges, ISO-KF flange connections with nominal widths of DN 10 to DN 50 are used for detachable connections, for larger nominal sizes of DN 63 to DN 1000 ISO-K and ISO-F flanges are used. Ultra-high vacuum compatible releasable connection, are in nominal widths DN 16 to DN 400 as a CF flange connection, respectively for larger nominal diameters of DN 400 to DN 800 flanges as a COF flange.