The 'heart' of a single-screw pump is a metal screw rotor, typically made of stainless steel or hardened steel. This precision-machined helix rotates eccentrically, propelling a fixed volume of medium forward with each revolution. The rotor's helix angle is specially designed to ensure thrust while preventing backflow, much like an elegant dancer guiding liquid flow with a spiral trajectory.
Complementing the rigid rotor is a flexible stator, usually made of corrosion-resistant rubber or polyurethane. The stator's internal cavity has a double-helix structure, with one more lead than the rotor. As the rotor planetarily moves within the stator, it creates continuously changing sealed chambers. These chambers gradually decrease in size from the suction end to the discharge end, generating a stable delivery pressure, like gentle hands continuously pushing the medium forward.
The choice of materials for this combination directly affects the pump's lifespan:
Food-grade applications: 316L stainless steel rotor, EPDM rubber stator
Wear-resistant applications: Tungsten carbide coated rotor with polyurethane stator
Corrosive environments: Hastelloy rotor with fluororubber stator
High-temperature applications: Chrome-plated steel rotor with heat-resistant NBR stator
