Double suction pumps use which type of impellers?

Double suction pumps use which type of impellers?

• A. Open
• B. Closed
• C. Semi-Closed
• D. Double-Entry

Answer: (B)

Double-suction pumps are designed so that liquid enters the impeller from both sides, creating a balanced flow that helps reduce axial thrust on the shaft. Because this arrangement relies on maintaining a tight, efficient flow path and handling higher pressures from two sides, a closed (shrouded) impeller is preferred. The closed impeller provides a rigid, sealed wheel with front and back surfaces that minimize leakage between the suction and discharge paths and preserve efficiency at high flow rates. Open impellers, while good for certain slurries or solids, would allow more leakage and be less efficient under dual-suction conditions. Semi-closed impellers are a compromise but still don’t match the robustness and leakage control of a closed impeller in this setup. The term double-entry relates to the suction arrangement, not the impeller type, so it isn’t the correct description of the impeller.

Double-suction pumps are designed so that liquid enters the impeller from both sides, creating a balanced flow that helps reduce axial thrust on the shaft. Because this arrangement relies on maintaining a tight, efficient flow path and handling higher pressures from two sides, a closed (shrouded) impeller is preferred. The closed impeller provides a rigid, sealed wheel with front and back surfaces that minimize leakage between the suction and discharge paths and preserve efficiency at high flow rates. Open impellers, while good for certain slurries or solids, would allow more leakage and be less efficient under dual-suction conditions. Semi-closed impellers are a compromise but still don’t match the robustness and leakage control of a closed impeller in this setup. The term double-entry relates to the suction arrangement, not the impeller type, so it isn’t the correct description of the impeller.