These adapters are KF-40 to ASA 4.5 (ANSI 1) with an O-Ring groove. They allow a KF fitting to be connected to an ASA/ANSI fitting. These adapters have an ISO-KF quick flange (NW-40) stub welded to an ASA 4.5 /ANSI 1 bored flange. The ASA/ANSI side has an O-ring groove. These adapters are made of 304 stainless steel.

KF connections join two similar sized flanges with a centering ring and surrounding O-ring in between. A hinged clamp fastens the KF joint. ASA/ANSI connections always mate an O-ring grooved flange with a smooth (non-grooved) flange. The seal is made with an O-ring and the flanges are fastened with through-hole bolts, nuts, and washers.

Dimensions:

• A = 1.65" (42mm)
• B = 1.49" (38mm)
• C = 4.2" (108mm)
• O-Ring Groove (ID) =1.88" (47.5) mm

ASA flanges are available with a smooth or grooved face, rotatable or non-rotatable, bored or non-bored, and are named for the outer diameter of the flange, from 4.25 to 19 inches. The ANSI name for the same flange size corresponds to the nominal tubing size that can be welded to it, and ranges from 1 to 12 inches in diameter.

ASA / ANSI flanges were originally used for steam pipes but have now been adapted to vacuum. Diffusion pumps, roots blowers, cryopumps and large rotary piston pumps are some examples of vacuum pumps where these flanges are used. When sealed together with O-rings made of Viton, Buna or Silicone, they are capable of achieving vacuum pressures as low as 1x10^-8 Torr.