🔍 Key Concepts

• Study the check valves at the top (near B) and bottom (near G) to determine which side must be suction and which side must be discharge. • Look at the diaphragm and air space (A and E) and think about what powers the motion of the pumping element – is it a motor/impeller or compressed air acting on a flexible member? • Remember that many diaphragm‑type pumps are self‑priming positive displacement pumps, and consider what that implies about needing (or not needing) positive suction pressure.

💭 Think About

• Trace the liquid’s path: if liquid enters through one port, which way would each check valve swing, and where must the liquid leave the pump? • Ask yourself what feature in the drawing shows that the pump is operated by air, not by an electric motor or rotating shaft. • Compare this internal arrangement with what you know about centrifugal pumps versus positive displacement pumps – which one has diaphragms and check valves instead of an impeller?

✅ Before You Answer

• Verify which arrows on the valves show flow direction, then match that with the labels C and G to identify suction versus discharge. • Confirm whether the pump casing and diaphragm arrangement indicate a reciprocating/diaphragm positive displacement design rather than a rotary/centrifugal design. • Consider whether a diaphragm pump driven by air can typically lift liquid from below the pump (self‑priming) or if it would truly require positive suction pressure.