🔍 Key Concepts

• Positive displacement rotary pump operation (how flow is produced) • Effect of internal leakage (slip) on capacity and pressure • Relationship between clearance and cavitation

💭 Think About

• If the space between rotor and casing gets larger, what happens to the amount of liquid that can leak back from discharge side to suction side? • Does a rotary pump primarily build pressure by tight clearances, or by the volume it traps and delivers each revolution? • Would larger internal clearances make it easier or harder for the pump to maintain its designed output flow rate?

✅ Before You Answer

• Identify which choice directly relates to internal leakage and delivered flow (capacity) • Consider whether increased clearances would tighten or loosen any clearances elsewhere in the pump • Ask whether cavitation risk is more about suction conditions (NPSH) or about internal mechanical clearances alone