Concentric Butterfly Valves and valve shaft using the link way down Hole and shaped shaft to achieve a non-functional link pin down the disc's floating around in the opening and closing process of the disc, reducing interference between the disc and seat area, thereby greatly reducing the torque. Disc floating structure to achieve a single eccentric production process, change the eccentric of use. In the body cavity with anti-disc had bit stopper, ensure the disc is not in place when closed. Between the upper and lower valve body cavity under the valve shaft and shaft bore hole plate with butterfly bush is protected against larger particles within the medium into the valve shaft hole.