How a Flexible Impeller Pump Works | Rotary Pump Mechanism Explained

This animation explains the working principle of a Flexible Impeller Pump, a type of positive displacement rotary pump widely used in marine, food, and chemical applications. The pump uses a flexible rubber impeller that rotates inside an eccentric casing. As the impeller blades bend and unbend during rotation, they create variable chamber volumes—drawing fluid in on one side and pushing it out on the other. The pump operates through three stages: suction, transfer, and discharge. In the suction zone, vanes straighten to create a vacuum that draws fluid in; in the transfer zone, the fluid is carried between vanes in sealed chambers; and in the discharge zone, the vanes bend again, compressing and expelling the fluid. The elastic deformation of the impeller ensures continuous flow, excellent self‑priming, and gentle handling of fluids—even viscous or sensitive ones.