Combined wedge-shaped expansion and contracting double-plate valve

The utility model relates to a combined wedge-shaped expansion and contracting double-plate valve. The valve comprises a valve body, a valve base, a valve plate and a valve rod. A wedge disc is an expansion and contracting combined type wedge disc which comprises a left wedge disc body, a right wedge disc body, a wedge disc frame, a supporting base and a positioning frame. The outer side of the left wedge disc body and the outer side of the right wedge disc body are respectively provided with a sealing face which is matched with the valve base, the inner side of the left wedge disc body and the inner side of the right wedge disc body are matched with a center hole of the wedge disc frame through cylindrical pins in a movable mode, the inner side of a square groove of the wedge disc frame is sleeved with the upper end of the supporting base, a spring is installed between the inner wall of the lower end of supporting base and the lower end face of the wedge disc frame, the outer side face of the supporting base