The seal ring looks like a  T-shape cross-section. After zy-loc is stalled, T-shape rib is retained by the end-faces of two hubs and form a entirety with the main tube, and enhance the joining strength greatly; the two arms of T-shape form sealing lip, and form a sealing region with the inner taper surface of hub, this region is like a spring, under pressure, it can stretch freely in the range of yield stress and form sealing .

The seal principles of the seal ring is that it engenders heavy pressure between the seal ring and the wedge surface of the hubs due to the expansion of seal ring under internal pressure and there has formed one kind of self-sealing enhanced. So that such kind of self-sealing has ability to prevent the leakage. When the flange has been assembled well, the foot of the T section and the pipeline part have formed one whole part connected by the hubs and clamps. Such whole part has increased greatly the security of the connection through raising the intensity of the whole part. In additional, the two arms of the T-shape section had formed one kind of sealing-lips. The sealing-lips and the surface of the pyramid of the inner part of hubs consist of sealing area which is same as a kind of spring. And the materials of the sealing area could be flexible action within the submitted stress under outside force. The real and enhanced seal has been formed.