Abstract: The present invention is directed to a coupling assembly for sealingly coupling a first tube and a second tube. The coupling assembly comprises a first and a second tubular fitting, a flange on the first tubular fitting, a flange on the second tubular fitting, and a gasket. The assembly is preferably sealed by a clamp. The first tubular fitting has a proximal end for receiving a first tube and a distal end bearing the flange. The flange has a protective ridge thereon which extends outwardly from the flange. The second tubular fitting also has a proximal end for receiving a second tube and a distal end for bearing a flange. The flange of the second tubular fitting has a recess therein which is non-contiguous to the inside of the second tubular fitting. The ridge of the flange of the first tubular fitting projects into the recess of the flange of the second tubular fitting to form a close fit and partially filling the depth of the recess to form a gasket space.