Ball Valves — API 6D & ISO 17292

What is a Ball Valve?

A ball valve uses a sphere with a through bore, held between two seats. A quarter turn lines the bore up with the pipe for flow or turns it across to shut off. Ball valves give tight shutoff, fast operation and, in full bore form, low pressure drop and pigging capability. In a floating ball design the line pressure pushes the ball onto the downstream seat; in trunnion-mounted designs the ball is fixed on trunnions and spring-loaded seats seal against it, reducing operating torque in larger sizes and higher classes.

Key features

• Floating ball and trunnion-mounted designs
• Full bore and reduced bore; double block and bleed on trunnion valves
• Soft seats (PTFE, RPTFE, PEEK, nylon) or metal seats with hard coating
• Fire-safe design (fire type-testing to API 607 / ISO 10497 when the order specifies) and anti-static, blow-out-proof stem
• Lever, gear or actuator operation; ISO 5211 mounting pad

Specification

Applications

• Oil and gas pipelines and manifolds
• Refinery and petrochemical isolation
• Natural gas and LPG systems
• Chemical and water treatment
• Low-temperature service in LCC / LF2 / stainless

Floating vs trunnion ball valve

In a floating ball valve the ball is held only by the seats and line pressure pushes it against the downstream seat to seal. It is simple and economical in smaller sizes and lower classes. In a trunnion-mounted valve the ball is fixed by upper and lower trunnions and spring-loaded seats move onto it, so operating torque stays lower and it suits large sizes, high classes and double block and bleed duty.