US Patent 7438519 Sealing system for slurry pump

An improved slurry pump sealing system that employs a mechanical seal assembly fixed for axial movement with a bearing housing that moves axially to adjust pump impeller clearance. The relative relationship between the seal components remains unchanged regardless of the axial position of the shaft, impeller, and bearing housing. A contraction assembly with interconnecting members contracts to accommodate the reduction of the distance between the pump casing and shaft bearing housing on adjustment of pump impeller-to-casing clearance. In one embodiment the contraction assembly is a telescoping arrangement. In other embodiments, bellows are employed.