Operation Manual
3.0 Description of pump or pump unit
3.1 General pump description
The pump supplied is a positive
displacement pump, which may be supplied
bare shaft (see below) or with a drive unit .
The drawing below indicates various parts of
the pump.
3.2 Principle of operation
The pumps are of the positive displacement
rotary type with trilobe rotors. The direction
of flow is reversed by changing the direction
of rotation of the pump's drive shaft. The
pumping principle is as follows.
The volume at the inlet increases when the
rotors rotate and the product is drawn into
B
D
the pump. It is then transported in the space
between the lobes and the periphery of the
A
rotorcase to the discharge side, where volume
between the rotors is reduced and the product
is discharged.
E
C
Bareshaft pump
Item
Description
A
B
C
D
E
Rotors
Rotorcase
Bearing Housing
Gear Housing
Feet
STP125 Page 8
