US Patent 7416525 Rotary blood pump

Various “contactless” bearing mechanisms including hydrodynamic, hydrostatic, and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. These design features may be combined. In one embodiment, the pump apparatus includes a rotor having a bore, a ring-shaped upper rotor bearing magnet, and a ring-shaped lower rotor bearing magnet. The bearing magnets are concentric with the bore. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.