What plugs space between impeller and casing?

• A. wear rings
• B. gaskets
• C. seals
• D. bearings

Answer: (A)

The space between the impeller and the casing is filled by wear rings. These close-fitting rings sit around the impeller and inside the casing to create a small, controlled clearance. This reduces internal leakage from the discharge side back to the suction side, which helps maintain pump efficiency and protects the impeller and casing from wear. Wear rings are designed to wear over time and can be replaced to restore proper clearance and performance. Gaskets seal joints between sections, not the internal gap around the impeller. Seals prevent leakage around the shaft, not between the impeller and casing. Bearings support the rotating shaft and do not seal that gap. So wear rings are the correct component for plugging that space.