This is a 1 inch blank smooth ASA flange with NO O-Ring groove. These flanges are made with no weld prep and have no tubing bore. They are used to cover ASA ports. Both sides are smooth with NO O-Ring groove. They are made of 304 Stainless Steel. 

Common Dimensions: 

A = 4.25 in

B = 3.125 in, Diameter 0.625 in 

C = 0.50 in 

ASA ANSI flanges come in smooth or grooved flanges, bored or non bored, rotatable or non rotatable, and adapters to other flange types. With tubing sizes ranging from 1 in. to 12 in. diameter and outer diameters from 4.25 in. to 16 in. The Sizes of ASA are from 1 in. to 10 in. The two flanges that will mate can be two alike smooth flange faces or two unlike, one smooth face and one groove face. The flanges are mated together with nuts, bolts and washers. (See graphic below) 

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 the ASA flange uses. Using O-Rings with Viton, Buna or Silicone they are capable of achieving pressures as low as 1x10-8 Torr. We have a complete line of ASA flanges, adapters, O-rings and bolt kits to fit your most demanding needs.