A closing element described as a ball, cone, or occasionally a disk pressed against a seat is characteristic of which valve type?

• A. Slide valves
• B. Poppet valves
• C. Check valves
• D. Ball valves

Answer: (B)

Poppet valves seal by a movable closing member pressed directly against a fixed seat. That closing element can be ball-shaped, conical, or a flat disk, depending on the design, and when the valve is closed it sits firmly on the seat to form the seal. This direct-contact closure and the variety of closing shapes are the hallmark of poppet valves, commonly used where tight, reliable sealing and quick actuation are important. Other valve types operate differently: sliding valves rely on a gate that moves to block ports, not a poppet pressed onto a seat; while check valves may use a disk or ball to prevent backflow, their defining feature is one-way flow rather than a poppet-style seat seal; ball valves use a rotating ball as the closure element, which is a different mechanism from a poppet pressing onto a seat.