The difference between the three common vacuum flange specifications (CF, KF, ISO)
Recently, I have often encountered people asking about the structure of vacuum flanges, such as what is a CF flange? What is a KF flange? What is an ISO flange? The ISO flange is divided into ISO-K and ISO-F. So what is the difference and connection between them? Indeed, these flanges are commonly used flange standards in vacuum system design and configuration, and non-professionals are indeed easily confused. Therefore, Kejia Electric Furnace will list the structures and applicable standards of the three flanges here. Come out, hope to help everyone.
1. CF flange
The English name of CF flange is Conflat Flang. It is a flange connection used in ultra-high vacuum, and it is a metal static seal that can withstand high temperature baking.
The nominal diameter size includes: DN16, 40, 63, 100, 160, 200, 250.
Applicable vacuum up to 10-12 mbar (10-14Pa).
Flange sealing materials are usually Viton, PTFE, oxygen-free copper, etc.
The flange is usually 304, 316 stainless steel, etc.
CF flanges are suitable for vacuum standards:
GB/T 6070-2007 Vacuum Technology Flange Dimensions
GB/T 6071-2003 Ultra-high vacuum flange
2. ISO-KF
ISO-KF is a quick-release flange used in vacuum systems. It consists of the following components: two symmetrically distributed KF flanges, O-Ring, centering bracket, and clamp. The connection can be loosened or tightened by simply turning the wing nut by hand without the use of other tools.
The ISO-KF vacuum joint is a small size quick-fit flange joint. The nominal diameter size includes: DN 10, 16, 25, 40, 50.
Manufacturing standards include: DIN 28403, ISO 2861.
Applicable vacuum up to 10-8 mbar (10-10Pa).
Flange sealing materials are usually Viton, Buna, Silicone, EPDM, aluminum, etc.
The flange is usually 304, 316 stainless steel, etc.
ISO-KF vacuum joints usually consist of flanges, clamps, O-Rings, and centering rings.
ISO-KF applicable vacuum standard:
GB/T 4982-2003 Vacuum Technology Quick Release Connectors Dimensions Part 1: Clamping Type
GB/T 4983-2003 Vacuum Technology Quick Release Connectors Dimensions Part 2: Tightening Type
3. ISO flange
ISO flanges and piping can be used in a variety of applications from atmospheric pressure to high vacuum, often assembled and disassembled. Typical pipe diameters exceed 50 mm (2 inches). If using Viton O-ring, it can withstand 150℃ baking.
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, nominal diameter sizes include: DN 63, 100, 160, 200, 250, 320, 400, 500 and 630.
Manufacturing standards include: DIN 28404, ISO 1609
Can be used in occasions that require a vacuum of up to 10-8 mbar.
Flange sealing materials are usually Viton, Buna, Silicone, EPDM, aluminum wire, etc.
The flange is usually 304, 316 stainless steel, etc.
a. ISO-K vacuum joints usually consist of flanges, clamps, O-Rings, and centering rings.
b. ISO-F vacuum joints are usually composed of flanges, O-Rings, and centering rings. The difference from ISO-K is that the flanges are firmly bolted.
ISO flanges are suitable for vacuum standards:
Type and size of JB/T 1090-1991 J type vacuum rubber sealing ring
JB/T 109l-1991 JO type and skeleton type vacuum rubber sealing ring type and size
Type and size of JB/T 1092-1991 O-type vacuum rubber sealing ring