What is Volute (pump)?

The volute is a curved funnel that increases in area as it approaches the discharge.The volute of the centrifugal pump is the casing that receives the fluid pumped by the impeller and maintains the velocity of the fluid through the diffuser.When liquid leaves the impeller it has high kinetic energy and the volute directs this flow to the discharge.

As the fluid flows along the volute,more and more fluid exits the impeller, but as the cross-sectional area of the volute increases, the velocity will remain constant if the pump is run close to the design point.If the pump has a low flow rate, the velocity across the volute is reduced, causing pressure to rise which causes lateral thrust across the impeller, which we see as vibration.If the pump flow rate is higher than the design flow rate, the velocity through the volute increases and the pressure decreases, according to the first law of thermodynamics.This will cause a sideways thrust in the opposite direction to that caused by low flow, but the result is the same reduced bearing and seal life due to vibration.The volute does not convert kinetic energy into pressure this is done at the diffuser by reducing the velocity of the liquid while increasing the pressure.The name "volute" was inspired by the fact that this shell resembles the scroll-like portion near the top of the ionically ordered columns in classical architecture called the volute.

Split volute

In a split volute or double volute pump, the path along the volute is divided to provide two distinct discharge paths.These streams start at 180 degrees from each other and join when they reach the discharge. This arrangement helps to balance the radial forces on the bearing.