Brochure

Impeller Inlet
1414
1. Introduction to Centrifugal Pumps
1.2.1 Inlet flange and inlet
The pump is connected to the piping system through its
inlet and outlet flanges. The design of the flanges depends
on the pump application. Some pump types have no inlet
flange because the inlet is not mounted on a pipe but sub-
merged directly in the fluid.
The inlet guides the fluid to the impeller eye. The design of
the inlet depends on the pump type. The four most com-
mon types of inlets are inline, endsuction, doublesuction
and inlet for submersible pumps, see figure 1.3.
Inline pumps are constructed to be mounted on a straight
pipe – hence the name inline. The inlet section leads the
fluid into the impeller eye.
Endsuction pumps have a very short and straight inlet sec-
tion because the impeller eye is placed in continuation of
the inlet flange.
The impeller in doublesuction pumps has two impeller eyes.
The inlet splits in two and leads the fluid from the inlet
flange to both impeller eyes. This design minimises the axial
force, see section 1.2.5.
In submersible pumps, the motor is often placed below the
hydraulic parts with the inlet placed in the mid section of
the pump, see figure 1.3. The design prevents hydraulic los-
ses related to leading the fluid along the motor. In addition,
the motor is cooled due to submersion in the fluid.
Figure 1.3: Inlet for inline, endsuction, doublesuction and submersible pump.
Inline pump Endsuction pump Doublesuction pump Submersible pump
Impeller Inlet
Impeller Inlet
Impeller Inlet