🔍 Key Concepts

• Direct-reversing diesel engine and what happens to attached pumps when engine rotation changes • How impeller vane shape and casing geometry (concentric vs volute) affect performance and directionality • Differences between ability to rotate and efficiency/performance when rotating in either direction

💭 Think About

• Ask yourself what a straight impeller vane looks like compared to a curved one, and how that might affect the pump’s behavior if shaft rotation is reversed. • Think about what a concentric pump housing does differently from a volute housing in terms of flow direction and pressure distribution. • Consider which choice describes a basic mechanical possibility, and which choice describes performance/quality of operation in both directions.

✅ Before You Answer

• Clarify in your mind the difference between mechanical capability to turn and maintaining similar hydraulic performance in both directions. • Recall that volute casings are typically designed for one direction of rotation; how does a concentric casing change that? • Check which options are specifically about direction of rotation versus unrelated issues like clogging or cavitation.