What is the flange?
A flange is a protruded ridge, lip or rim, either external or internal, that serves to increase strength (as the flange of an iron beam such as an I-beam or a T-beam); for easy attachment/transfer of contact force with another object (as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera); or for stabilizing and guiding the movements of a machine or its parts (as the inside flange of a rail car or tram wheel, which keep the wheels from running off the rails). Flanges are often attached using bolts in the pattern of a bolt circle. The term “flange” is also used for a kind of tool used to form flanges.
3 Most Common Flange Types
Vacuum flanges are mostly used for vacuum tube furnaces, and three most common flanges are:
- CF flange
- KF flange
- ISO flange
What are the differences and connections between them? Here we will list the structure of the three flanges and the applicable standards one by one, hope to help you.
1、CF flange
Conflat Flange, is a kind of flange connection used in ultra-high vacuum, is a metal static seal, and can withstand high-temperature heating.
- Nominal diameter sizes include DN16, 40, 63, 100, 160, 200, 250.
- Suitable for vacuum levels up to 10-12 mbar.
- Flange sealing materials are usually Viton, PTFE, oxygen-free copper, etc.
- Flanges are usually 304, 316 stainless steel, etc.
2、ISO-KF flange
ISO-KF is a kind of quick-release flange used in a vacuum system. It consists of the following components: two symmetrically distributed KF flanges, O-Ring, a centering bracket, and a clamp. The coupling can be loosened or tightened by simply twisting the disc nut by hand without the use of additional tools.
- ISO-KF vacuum couplings are small-size quick-release flange couplings.
- Nominal diameter sizes include DN 10, 16, 25, 40, 50.
- Manufacturing standards include DIN 28403, ISO 2861.
- Suitable for vacuum levels 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 couplings are usually composed of flanges, clamps, O-Rings, and centering rings.
3、ISO flanges
ISO flanges and piping can be used in a variety of applications from atmospheric pressure to high vacuum, often assembled and disassembled. Generally, the diameter of the tube is more than 50mm (2 inches). If the use of fluorine rubber O-ring can withstand 150 ℃ baking.
- The two common forms of ISO flanges are ISO-K and ISO-F.
- ISO-K and ISO-F vacuum couplings are large-size vacuum couplings with nominal diameter sizes including DN 63, 100, 160, 200, 250, 320, 400, 500, and 630.
- Manufacturing standards include DIN 28404, and ISO 1609.
- They can be used in applications requiring vacuum levels up to 10-8 mbar.
- Flange sealing materials are usually Viton, Buna, Silicone, EPDM, aluminum wire, etc.
- Flanges are usually 304, 316 stainless steel, etc.
1）ISO-K vacuum couplings usually consist of flanges, flange jaws, O-Ring, and a centering ring.
2）ISO-F vacuum couplings usually consist of flanges, O-Ring, and a centering ring, but the flanges are bolted.
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