🔍 Key Concepts

• Relief valve function in a centrifugal or positive-displacement cargo pump • What happens if a discharge valve is shut while the pump is still running • Difference between system protection vs normal operating features (filling, venting, shutdown)

💭 Think About

• Think about what could be damaged if a cargo pump keeps running against a closed discharge line. What is the relief valve protecting? • Which option describes a path for liquid when system pressure gets too high, rather than a normal operating function like filling tanks or venting vapors? • Does a relief valve usually move liquid somewhere else in the cargo system, or does it directly control starting/stopping the pump?

✅ Before You Answer

• Identify which choice describes overpressure protection rather than routine operations • Check which option involves returning liquid flow rather than handling vapors or electrical shutdown • Ask: if all discharge valves were closed and the pump kept running, which option would prevent damage by giving the liquid somewhere safe to go?