When you Wholesale Cast Steel Butterfly Valve, you should know the butterfly valve is also called a disc valve, and the opening and closing member is a disc-shaped disc plate and can rotate around the axis of the valve body. Mainly composed of valve body, valve stem, disc and sealing ring. The valve body has a cylindrical shape with a short axial length and a built-in disc. The disc plate is driven by the valve stem. If it is rotated through 90°, it can be opened and closed once. The flow rate of the medium can be controlled by changing the deflection angle of the disc. The main seal is a sealing ring. The butterfly valves commonly used according to the application and medium have two types: clip-on butterfly valve and flange type butterfly valve. The wafer type butterfly valve uses a stud bolt to connect the valve between the two pipe flanges. The flange type butterfly valve has a flange on the valve, and the flanges on both ends of the valve are connected to the pipe flange by bolts.