Flexible Impeller pumps are used mainly in grey water and black water transfer, engine cooling, baitwell and air conditioning along with other essential functions on boats and ships. General description are pedestal style or flange mounted. Flexible impeller pumps are designed for general transfer of thin or viscous fluids. Liquids handled by flexible impeller pumps with standard Neoprene impellers are primarily used for fresh or salt water and water solutions. If pumping various petrochemicals, a Buna N impeller is also available. Liquid temperatures range from 40° f to 140° f (4.4° c to 60° c). If freezing conditions are expected the pump should be drained and the pump chamber should be filled with antifreeze.
On initial startup Flexible impeller pumps must be primed to prevent dry-running of the impeller. Suction lifts of 15 feet are possible when pump is fully primed. A foot valve with a built in strainer at the beginning of the suction line is recommended. Suction lines should be as short as possible. Horizontal runs, if necessary, should be pitched upwards toward the pump.
All pedestal and flange mounted pumps are made of high quality bronze of maximum corrosion resistance. All shafts consist of stainless steel grade 303. They consist of either ball bearings and mechanical seals or carbon bearing with a lip seal. Impellers are made of Neoprene Rubber however Buna (Nitrile) impellers are also available.
How does a flexible Impeller pump work?
Flexible impeller pumps are positive-displacement pumps. The rotor with flexible vanes is mounted centered in a circular housing which has a compressed area at one side. Flexible blades on the periphery of the impeller provide pumping action. While the impeller rotates the liquid between the blades is continuously squeezed out into the discharge port by a cam located inside the pumping chamber. The flow may be throttled or shut off for a short period on the discharge side without the need for a relief valve.
Suction Flow Discharge