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Vacuum KF Coupling

KF Union (KF Clamp, KF Flanges, KF Centering Ring)

In the 1950s, the Klein Flange company developed the KF couplings, or Quick Flange (QF) couplings, and ever since, it has been commonly used in vacuum and ultra-high vacuum applications. The easiest way to identify an KF Clamp is its O-ring seal that is supported by a centering ring, and they come in sizes from 10mm to 50mm.

The KF Union contains a KF Clamp, Two KF Flanges, and a KF Centering Ring with Seal. They can be mated with KF Bored Flanges, KF Blanks, and other KF Components. When the flanges are connected, the centering ring provides a seal that prevents air from leaking into the vacuum system, even in conditions with temperature and pressure.

KF Couplings are easy to use because they do not require special tools to assemble or disassemble. 


Coupling Material

KF Clamp in Aluminium, KF Flanges and KF Centering Ring in SS 304 or SS 316L

Seal Material


Size Ranges

From KF10 to KF50

Internal Surface Finish

< 1μm


KF Clamp

To fasten the union by tightening the wingnut.

KF Flange

To be welded to tubes.

KF O Ring

Acts as a seal to prevent leakages.

KF Centering Ring

Acts as a frame for the O Ring.

KF Blank Flange

Acts as a cover to to block flow.

Malaysia KF Coupling
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