.com Forum · Banner Making Forum

What are the differences between CF, KF, and ISO vacuum flanges? CF vacuum flanges are all-metal sealing methods and are widely used in ultra-high vacuum systems. KF vacuum flanges are a quick-release method used in vacuum systems. Flange, the diameter of ISO general pipe is more than 50mm (2 inches), which can be used in various applications from atmospheric pressure to high vacuum, which are often assembled and disassembled. Next, let's take a look at CF, KF, ISO vacuum flanges.

CF VACUUM FLANGE
The inner side of the CF vacuum flange has a raised sharp knife edge, which is used to seal the vacuum by squeezing the oxygen-free copper gasket (or other soft metal) to deform it. It is an all-metal sealing method and is widely used in ultra-high vacuum systems. CF flanges are also commonly referred to as ICF flanges. The number after CF is the standard inner diameter of the conduit, and the number after ICF is the outer diameter of the flange.

CF flanges are divided into two types: fixed type and loose type. The fixed flange is an integrated structure. Loose sleeve flanges consist of a knife-edge portion extruded by copper washers and a fixed portion through bolts. Flanges can have holes or tapped holes. Flanges with through holes should be fixed with bolts and nuts; flanges with threaded holes can be directly fixed with bolts. The material of the flange is mainly SUS304 (or SUS304L). Because SUS304 emits less gas, it is easier to process and weld.

The characteristic of CF flanges is that they are all made of metal, including oxygen-free copper gaskets, so they can withstand high temperatures (above 250 ?) baking. The disadvantage is that the price is high, and the oxygen-free copper gasket cannot be reused many times.

KF VACUUM FLANGE
KF is a quick-release flange used in vacuum systems. It consists of the following components: two symmetrically distributed KF flanges, O-Rings, centering brackets, and clamps. No other tools are required to loosen or compress the coupling by simply turning the disc nut by hand.

ISO-KF vacuum fittings are small size quick flange fittings. Nominal diameter sizes include: DN 10, 16, 25, 40, 50.
The applicable vacuum is up to 10-8 mbar.
Flange sealing materials are usually Viton, Buna, Silicone, EPDM, aluminum, etc.
Flanges are usually 304, 316 stainless steel, etc.
ISO-KF vacuum fittings usually consist of a flange, clamp, O-Ring, and centering rings.

ISO VACUUM FLANGE
ISO vacuum flanges and piping can be used in a variety of applications, from atmospheric pressure to high vacuum, that is often assembled and disassembled. Generally, the diameter of the pipe exceeds 50mm (2 inches). Can withstand 150°C bake if Viton O-rings are used.
The two commonly used forms of ISO flanges are ISO-K and ISO-F
ISO-K and ISO-F vacuum fittings are large-size vacuum fittings in nominal diameters: DN 63, 100, 160, 200, 250, 320, 400, 500 and 630
Manufacturing standards include: DIN 28404, ISO 1609
Can be used where vacuum levels up to 10-8 mbar are required.
Flange sealing materials are usually Viton, Buna, Silicone, EPDM, aluminum wire, etc.
Flanges are usually 304, 316 stainless steel, etc.
ISO-K vacuum fittings are usually composed of the flange, claw, sealing ring (O-Ring), and centering ring.

https://www.bowahvacuum.com/products/vacuum-components/kf-series
https://www.bowahvacuum.com/products/vacuum-components/iso-series
https://www.bowahvacuum.com/products/vacuum-components/cf-series