Type C & CS Stub Ends
Stub Ends are fittings used in place of welded flanges where rotating back up flanges are desired. They are also called Lap Joints and Vanstone Flared Laps. A rotating back up flange seats itself against the back surface of the Stub End. When bolts are added, the clamping action of the bolts presses the rotating back up flange against the back of the Stub End. The gasket surface of the Stub End then presses against a gasket and another gasket surface providing joints like standard flange joints. The seal is made by the gasket surface of the stub end alone, the flange only provides the clamping pressure on the joint. As per ASME B 31.3 paragraph 306.4.2 the flared lap is suitable for use in normal fluid service.
Since Stub Ends are made from material compatible with the designed piping system, back up flanges do not have to be made from the same material. The flange can be made from less expensive material because it never comes in contact with the process fluid.
Stub Ends are available in two standard lengths, MSS and ANSI and are normally provided with a standard weld bevel. Stub end dimensions are shown below. Submit an RFQ.