What is ISO-KF flange?

What is ISO-KF flange?

ISO-KF small flange components are described in DIN 28403 and ISO 2861 in nominal diameters DN 10 to DN 50. The connections suitable for pressures up to 1 · 10-8 hPa and can be used for overpressures up to 1,500 hPa. With metal seals, the pressure range can be extended to less than 1 · 10-9 hPa. The significantly higher contact pressures required for this are created with special clamps for metal seals. An ISO-KF connection consists of two symmetrical flanges and one O-ring seal, which is positioned and supported with an internal or external centering ring (Figure 3.7). The necessary pressing force for the sealing is created by a clamping ring, which is placed over the conical tightening area and is tightened with a wing screw. This allows for a fast, efficient assembly and disassembly without any tools. The flanges can be aligned around its main axis in any direction. For mounting a KF flange on a base plate, (Figure 3.8)

claw clamps or bulkhead clamps are used as clamping elements. The dimensions of the bores in the base plate can be found in the product description of the claws and bulkhead clamps.

Figure 3.7: ISO-KF connection with centering ring and clamping ring

Figure 3.8: ISO-KF flange mounted on base plate with centering ring and claw clamps

However, NW flanges have two major problems: one is the limited heat resistance during equipment baking; the other is the air permeability of hydrogen and helium.