Close-coupled Flexible Impeller Pumps are made of high quality bronze for maximum corrosion resistance. The rubber impeller is mounted on a separate stainless steel shaft, which is on the outer end in order to slide over the carbon steel motor shaft. Ball or sleeve bearings in the motor or engine support the shaft. Model 405M has a mechanical seal. Impellers are made of Neoprene rubber, Nitrile impellers are available on request.
Flexible blades on the periphery of the impeller provide the 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 without the need of a relief valve.
Close coupled Rubber Impeller Pumps are mounted directly onto the motor without the use of a shaft coupling. This pump is designed to be coupled to a Nema C 56C faced motor. It uses an aluminum adapter plate to accommodate the pump. The gas engine mount has its own adapter.
Liquids handled by Rubber Impeller Pumps with standard Neoprene impellers are primarily fresh or salt water and water solutions. Rubber Impeller Pumps are not suitable for pumping gasoline or solvents. Nitrile (405M-07) impellers can handle oil-contaminated water and kerosene at reduced impeller service life. Liquid temperature range is from 40°F to 180°F. If freezing conditions are expected, the pump should be drained by loosening the cover screws and the pump chamber should be filled with methyl alcohol based antifreeze. Viscous liquids and oils cannot be pumped with Rubber Impeller Pumps.
On initial start-up Rubber Impeller Pumps must be primed to prevent dry running of the impeller. DO NOT RUN DRY. Suction lifts of 15 feet are possible when pump is fully primed. A foot valve with built-in strainer at the beginning of the suction line is recommended. Suction lines should be as short as possible.