IMO Model 3E pumps are three screw, positive displacement, rotary pumps designed and engineered for excellent suction capability over a wide range of fluid viscosities. Flow rates (1 to 100 GPM) are proportional to rotating speed when the pump is operated within the recommended pressure range. The pump has the ability to self-prime in a piping system designed to facilitate this feature.

The unique IMO design - only three moving parts - is the key to the model 3E pump performance. A precision bored housing encases the driven screw (power rotor) and intermeshing sealing screws (idler motors). The accurately machined idler rotors conform perfectly to the threads of the power rotor and to the housing bores confining the fluid in a succession of closures or cavities. As the screws rotate, the fluid is moved axially from the inlet port to the outlet port in a continuous, uniform flow. This uniform axial flow results in a minimum of fluid pulsation and extremely quiet operation.

The rotating idler rotors generate a hydrodynamic film of fluid which supports the idlers in the housing mores and prohibits wearing contact. The strength of this film is based on fluid viscosity, pump pressure, and speed. As pressure requirements increase, the hydrodynamic film can be strengthened by increasing viscosity or speed. Both the flow rate and pressure capability of the IMO pump increase with speed; thus higher speeds generally result in better performance and longer life.

The symmetrical arrangement of the rotors (screws) eliminates the need for bearings to absorb radial loads. Model 3E pumps contain only one ball bearing which positions the power rotor for proper operation of the mechanical seal. This permanently grease-packed bearing is isolated from the pumpage by the mechanical seal to prevent contamination and improper lubrication.

Model 3E pumps are offered in ten rotors sizes for foot or flange mounted configurations. A variety of construction materials are available to meet operating conditions and job specifications. Complete pump/driver assemblies can be provided as required.

The simple compact design of the Model 3E pump permits fast, easy instillation and low maintenance. The bearing and shaft seal are easily replaced when necessary. The pump can be positioned in 90 degree increments to accommodate piping arrangements. Periodic inspection can be made without removing the pump, and routine maintenance can be performed without disturbing system piping.