The shaft and seat seal of ABC patented A73, A74, A75 series eccentric butterfly valve are self-sealing design. The higher the pressure, the tighter the seal. This Changes the history which the eccentric butterfly valve is difficult to two-way full pressure seal, shaft seal is easy to leak. So the valve can be functionally substituted for gate or globe valves within the allowable range of pressure. The eccetric valve is easy to install and connect, easy to debug, can be used as a cut-off valve or regulating valve in the pipeline, and the adjustment performance reaches the accuracy of the cut-off valve. The unique seat design allows the valve to be metal sealed. A73 is wafer connection and is suitable for most applications. A74 is a lug connection and is suitable for requiring unilateral disassembly for maintenance or end pipes. A75 is flanged connection, suitable for replace gate valve and globe valve.