Full definition
A ball valve is a type of quarter-turn valve that utilizes a spherical obturator with a hole through the center, allowing for efficient flow control. When aligned with the flow, the valve is in the open position, and when the ball is rotated 90°, the hole is perpendicular to the flow, effectively closing the valve. Ball valves are known for their high coefficient of flow (Cv), which results in minimal pressure drop across the valve when it is fully open, making them suitable for various applications requiring reliable shut-off and control. They are available in sizes ranging from 1/4" to 12" (DN8 to DN300) and can withstand pressures of up to 420 bar, with temperature ratings from -196°C to +200°C. This wide range of specifications makes ball valves versatile for different industries, including oil and gas, water treatment, and chemical processing.
There are two main types of ball valves: floating ball and trunnion-mounted. Floating ball valves rely on the ball's ability to compress the seat against the ball to create a seal, making them ideal for lower pressure applications. In contrast, trunnion-mounted ball valves are designed for high-pressure applications, featuring a ball that is supported by bearings at both the top and bottom, allowing for better stability and reduced wear under high-stress conditions. Common materials used for manufacturing ball valves include brass, 304 and 316 stainless steel, and carbon steel (A105), each offering different advantages in terms of corrosion resistance and strength.
Standards such as API 6D and ISO 17292 define the requirements for ball valve design and testing, ensuring reliability and safety in various applications. These standards govern not only the performance but also the manufacturing processes, which helps to maintain quality and consistency across the industry. Brands recognized for producing high-quality ball valves include Flowserve, Swagelok, Parker, Kitz, and Velan, which are known for their durability and performance under demanding conditions.