Balzers KF Flange Clamp Double Hinged 3/4 Inch Aluminum

The Balzers (Pfeiffer Vacuum) 86743091 KF Flange Clamp is a quick-release vacuum fastener designed for use with ISO-KF (Klein Flange) vacuum systems. While the "3/4 inch" designation refers to the corresponding tubing size, in vacuum terminology this clamp is sized for DN16 KF (NW16) flanges. Because DN10 and DN16 flanges share the same 30 mm outer diameter, this specific clamp is universally compatible with both KF10 and KF16 connections, making it a versatile component for forelines and roughing pump exhausts.

This "Double Hinged" (or double claw) model is constructed from die-cast aluminum, which offers a balance of strength and lightweight handling. The double-hinge design is generally preferred over single-hinge or three-piece clamps in tight spaces because the wider opening angle allows it to wrap around the flange assembly more easily. When the wingnut is tightened, the clamp applies uniform pressure to the tapered edges of the flanges, compressing the internal centering ring (O-ring) to create a vacuum-tight seal capable of holding pressures down to high-vacuum levels.