🔍 Key Concepts

• Centrifugal pump performance – how speed, clearances, and suction conditions affect discharge pressure • Wearing rings – their role in controlling internal leakage in centrifugal pumps • Difference between problems that change pump output directly vs. those that mainly cause mechanical stress/vibration

💭 Think About

• Ask yourself: Which option would most directly allow fluid to leak back from the high‑pressure side to the low‑pressure side inside the pump, reducing net discharge pressure? • For each choice, decide: would this normally increase pressure, decrease pressure, or mainly cause mechanical/maintenance issues? • Consider how changing pump speed affects the pump curve: does higher speed normally raise or lower discharge pressure?

✅ Before You Answer

• Identify which factor mainly affects internal clearances and recirculation inside the pump. • Eliminate any option that would normally increase discharge pressure rather than decrease it. • Eliminate options that are more about alignment and support than about hydraulic performance inside the impeller and casing.