What is the front and/or back of an impeller called?

• A. Casing
• B. Shroud
• C. Hub
• D. Impeller face

Answer: (B)

Shroud is the term for the front and back faces that surround the impeller blades. In a closed impeller, two shrouds enclose the blade passages, creating a sealed channel for the liquid and keeping the blade tips aligned. This design improves efficiency and reduces leakage between suction and discharge. The hub is the central boss that blades attach to, and the casing is the pump housing. The phrase “impeller face” isn’t standard terminology. Some impellers are open and lack shrouds on one or both sides, but when describing the enclosing surfaces around the blades, they’re called shrouds.