The separation of two counter rotating elements (rotors) creates a partial vacuum reducing the pressure at the inlet to the pump assisting product into the void created.

Product is carried around the casing between the rotor lobes in a controlled volume.

At the discharge of the pump the mesh of the rotor lobes creates a positive pressure causing the product to pass smoothly out the casing port.

With tri-lobe rotors this action occurs 6 times each revolution.

The rotors create a seal between pump inlet and outlet without contact with each other or the casing by accurately maintained clearances on all surfaces.