SYSTEM, METHOD AND APPARATUS FOR COMBINED BALL SEGMENT VALVE AND CHECK VALVE

摘要

A valve apparatus including a check valve and a ball segment valve is provided within a fluid system for handling a flammable working fluid. The valve apparatus is arranged such that flapper doors of the cheek valve longitudinally overlaps a ball segment of the ball segment valve when each are in respective open positions such that the valve apparatus maintains a face-to-face dimension of a standard ball valve. The valve apparatus can thus provide positive isolation and directional fluid control in a congested fluid system with space savings over single valves. An isolated chamber is defined between the flapper doors and the ball segment when each is in a respective closed position. A non-flammable fluid is injected into the isolated chamber to urge the flapper doors and ball segment toward the closed positions to thereby provide a safe environment for performing maintenance operations on downstream fluid components.