5
B.
General Description / Designation / Labeling
B.1 General Description
B.1.1 Imo 3-Screw General Description
Imo series pumps are single ended or double ended positive displacement, rotary screw pumps
consisting of a precision bored housing or housings that enclose a drive screw (power rotor) and two or
more intermeshing driven screws (idler rotors). These screws, when rotating, form a succession of
closures or cavities. As they rotate, fluid is moved axially from inlet to outlet port in a continuous,
uniform flow with minimum fluid pulsation and low pump noise. Fluid flowing through the pump provides
lubrication for moving parts.
B.1.2 CIG General Description
The CIG is a positive displacement, internal gear pump. Fluid enters the inlet chamber and is carried
across a crescent to the discharge chamber where it is forced out of the stage by the meshing of the
internal and external gear teeth. Fluid flowing through the pump provides lubrication to the moving
parts. The pump can be multi-staged to increase its pressure capability.
B.2 Designation
This manual applies to all Series of Imo pumps, including all 3-Screw pumps and CIG pumps.
B.2.1 Imo 3-Screw Designation (Except 3G)
B.2.2 Imo 3-Screw 3G Designation
