Vacuum pump accessories KF, ISO, NW, CF how to distinguish

Customers usually see some indications when using vacuum pump accessories. For example: KF, ISO, NW, CF, etc., how to distinguish them?


1. KF is a common sealing connection in daily vacuum system, which is mainly used in high vacuum system. The specifications range from kf10 to kf50. Generally, the pipe size of KF connection is relative to inch size. In other words, the corresponding pipeline of kf25 is 25.4 * 1.65mm, and so on (some require special pipes, and the welding size of flange can be customized). The vacuum connection from KF maximum to kf50 (piping is 50.8 * 1.65mm) is ISO series.


2. ISO is also used in high vacuum system accessories, the minimum specification is iso63 (piping is 63.5 * 1.65mm), followed by iso80, iso100, iso160, and even greater specifications. The connection mode is double clamp head connection, mainly two ISO flange plates, with sealing ring added in the middle, and then four double clamps are used to clamp the flange for connection. It should be noted that the ISO series sealing ring has an aluminum spring outer ring in addition to the center bracket and fluororubber sealing ring compared with the KF series vacuum sealing ring. Its main function is to prevent the seal ring from slipping off. Because the pipe size of ISO series is relatively large, the sealing ring is affected by the vibration or temperature of the machine platform on the central support. If it is not fixed, it will slip off and affect the sealing.

NW flange

3. NW is also used in high vacuum system vacuum parts, is the Japanese specification, so NW vacuum parts used in Japanese enterprises or Japanese equipment are relatively more. As we have said before, the ISO series is connected with two ISO flanges and four double hooks, while the NW connection mode is that two NW flanges are connected together and connected with chain clamp (the appearance of N63 flange is the larger nw50 flange).

CF flange

4. CF flange is easy to distinguish. It is mainly used for sealing connection in ultra-high vacuum system, and its main sealing mode is metal seal, namely copper gasket seal. Yazhilaide mechanical and electrical technology reminds us that the sealing effect of CF copper gasket will be very poor after using it once. If the system requires high vacuum degree, the vacuum pump accessory gasket needs to be replaced every time the flange is disassembled.

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