Volute (pump)

Pump and volute casing

The volute of a centrifugal pump is the casing that receives the fluid being pumped by the impeller, slowing down the fluid's rate of flow. A volute is a curved funnel that increases in area as it approaches the discharge port. The volute converts kinetic energy into pressure by reducing speed while increasing pressure, helping to balance the hydraulic pressure on the shaft of the pump.

Large water pump from the floating docks at Gloucester

The name "volute" is inspired by the resemblance of this kind of casing to the scroll-like part near the top of an ionic order column in classical architecture, called a volute.