The volute in a centrifugal pump serves to

• A. Stores lubricating oil
• B. Supports the shaft
• C. Converts velocity to pressure and collects water from impeller
• D. Filters debris

Answer: (C)

The volute serves to convert velocity into pressure and to collect water from the impeller. When the impeller accelerates water outward, it carries high velocity. The volute—a spiral casing with a gradually increasing cross-section—slows that flow and converts the kinetic energy into static pressure, creating head for the discharge. It also channels the water from the impeller to the discharge piping with minimal energy loss. It doesn’t store lubricating oil, support the shaft, or filter debris—that’s handled by separate lubrication systems, bearings support, and screens, respectively. So the volute’s job is the velocity-to-pressure conversion and directing the flow from the impeller to the outlet.