A volute Liner is a curved funnel increasing in area to the discharge port. It is often used with impeller pumps. As the area of the cross-section increases, the volute reduces the speed of the liquid and increases the pressure of the liquid. The main purposes of a volute casing is to help balance the hydraulic pressure on the shaft of the pump. Ma ...

http://http://www.sunbopump.com/Pump-Parts/High-Chrome-Alloy-Parts/Slurry-Pump-Volute-Liner-138.html