Why must suction piping be free of air leaks and air pockets?

Why must suction piping be free of air leaks and air pockets?

• A. They can help prime the pump
• B. They decrease system efficiency
• C. They can cause cavitation and reduce pump performance
• D. They have no effect on suction performance

Answer: (C)

Air in suction piping disrupts a steady column of liquid feeding the pump. Suction lines must deliver water to the impeller without gas pockets, so keeping the line free of air leaks and pockets preserves the prime and the available suction head. When air leaks or trapped air pockets are present, the local pressure at the pump inlet can drop below the liquid’s vapor pressure, causing cavitation. Cavitation forms vapor bubbles that collapse as they move into higher-pressure areas, which erodes the impeller, reduces flow and head, and can cause unstable operation or loss of prime. In short, air in the suction path lowers the effective suction head and leads to cavitation, directly harming pump performance.

Air in suction piping disrupts a steady column of liquid feeding the pump. Suction lines must deliver water to the impeller without gas pockets, so keeping the line free of air leaks and pockets preserves the prime and the available suction head. When air leaks or trapped air pockets are present, the local pressure at the pump inlet can drop below the liquid’s vapor pressure, causing cavitation. Cavitation forms vapor bubbles that collapse as they move into higher-pressure areas, which erodes the impeller, reduces flow and head, and can cause unstable operation or loss of prime. In short, air in the suction path lowers the effective suction head and leads to cavitation, directly harming pump performance.