CP Range of pumps use the helical rotor pumping principle . The heart of the Mono Pump is the single helix rotor which rotates eccentrically within a double helix, resilient stator of twice the pitch length of the rotor. The rotor of circular cross section creates a continuously forming cavity as it rotates.. The cavity progresses towards the discharge end, advancing in front of a continuously forming seal line, carrying the pumped material with it. As the stator open cross sectional area is always constant, the flow rate is continuous without pulsation.