
24 Practical Centrifugal Pumps
Figure 2.10
Mixed flow impeller and propeller vaned mixed flow type impeller
Figure 2.11
Pump with axial flow impeller
2.2 Pump casings
At the impeller outlet, the velocity of the liquid can be as high as 30–40 m/s. This
velocity has to be reduced within a range of 3–7 m/s in the discharge pipe.
Velocity reduction is carried out in the pump casing by recuperators. The kinetic energy
in the liquid at the outlet is converted to pressure energy by the recuperators.
Here, energy conversion has to be undertaken with a minimal loss to have an
insignificant effect on pump efficiency.
Some of the recuperators are: ...