Which valve is mounted on the top of the valve plate in a typical reciprocating compressor?

• A. Discharge valve
• B. Suction valve
• C. Both valves
• D. Neither

Answer: (A)

The valve plate in a typical reciprocating compressor contains two one‑way valves arranged for the gas flow path: the discharge valve sits on the top, and the suction valve is on the bottom. As the piston compresses, cylinder pressure rises above the discharge line pressure, causing the top-mounted discharge valve to open and push the high‑pressure gas into the discharge manifold. The suction valve on the opposite side opens during the intake stroke when cylinder pressure is lower than the suction line to let gas into the cylinder, then closes as pressure rises to prevent backflow. This top-positioned discharge valve is there specifically to vent the compressed gas into the discharge system efficiently.