A ball valve mainly consists of a valve body, ball, seat, stem, actuator (manual/electric/pneumatic), and seals.
Valve Body: As the main frame of the ball valve, it is usually made of cast steel, stainless steel, or forged steel and must withstand the pressure and corrosion of the pipeline system. Its structure is divided into one-piece and two-piece types: one-piece valve bodies offer better sealing and are suitable for high-pressure scenarios; two-piece types facilitate maintenance and replacement of internal parts.
Ball: The core component of the ball valve, it is usually solid or hollow, with a surface precision-ground or hard chrome-plated finish to improve wear resistance. The ball has a through-hole in the center, allowing for full opening or full closing with a 90° rotation. It has minimal flow resistance and a near-linear flow characteristic.
Seat: It directly contacts the ball to form a seal. The material must be selected according to the characteristics of the medium. For example, soft-seal seats (such as PTFE) are suitable for low-temperature, low-pressure scenarios and offer excellent sealing; hard-seal seats (such as weld overlay) are used for high-temperature, high-pressure, or particulate media and offer stronger wear resistance.
Stem: Connects the ball to the actuator and must possess sufficient strength and corrosion resistance. To prevent media leakage, valve stems are typically designed with a top-entry structure and equipped with O-rings or packing seals.
Actuation devices: These are categorized into manual, electric, and pneumatic types based on operational requirements. Manual actuation uses a handle or worm gear for rotation; electric/pneumatic actuation uses a motor or cylinder and is suitable for automated control systems.
