Close-coupled Rubber 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 counter bored 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.