What are the four major components of a gate valve?

• A. Body, Bonnet, gate, and stem
• B. Body, Bonnet, seat, and stem
• C. Body, Cover, Gate, Stem
• D. Disc, Body, Bonnet, Stem

Answer: (A)

Gate valves rely on four parts that directly enable the opening and closing action: the body, which forms the pressure boundary and directs flow; the bonnet, the top closure that houses the stem and internal components and allows access for maintenance; the gate, the movable element that slides up and down to block or permit flow; and the stem, the rod that, when turned by a handwheel or actuator, raises or lowers the gate. The seating surfaces provide the seal, but they’re typically considered part of how the valve seals rather than a separate major component. Other options mislabel either the bonnet (calling it a cover) or replace the gate with a disc, which isn’t the standard terminology for a gate valve.