Two-piece ball valve and flanged gate valve are the same type of valve. The difference is that its closing part is a ball. The ball rotates around the center line of the valve body to achieve opening and closing. The ball valve is mainly used to cut off, distribute and change the flow direction of the medium in the pipeline. The Cantonese ball valve is a new type of valve that has been widely used in recent years. Commonly used in petroleum, chemical, natural gas, drainage, paper mills, and ships. Advantages: The fluid resistance is small, and the resistance coefficient is equal to the pipe section of the same length. The structure is simple, the volume is small, the weight is light, the operation is convenient, and the opening and closing is rapid. It only needs to rotate 90° from fully open to fully closed, which is convenient for remote control. The maintenance is convenient, the structure of the ball valve is simple, the sealing ring is generally movable, and it is convenient to disassemble and replace.