What is a 'sealless' centrifugal pump?
For most centrifugal pumps, the shaft has packing or a mechanical seal where the shaft enters the wet end. Fundamentally, a sealless pump substitutes a magnetic drive for the shaft seal. The impeller shaft is fitted with a magnetic rotor which is contained in a thin metal cover. The shaft, impeller, the rotor and the bearings are all "wet" components; that is, they are completely submersed in whatever liquid is being pumped. Over the outside of the magnetic rotor and cover is a magnetic drum which is driven by the power source, usually an electricmotor. The magnetic coupling between the rotor and drum delivers torque to the shaft and impeller. There are a number of variations in design, but all use sleeve type bearings lubricated by the pumpage.