A passive magnetically and hydrodynamically suspended rotary blood pump.

A combined hydrodynamic-magnetic bearing allows the design of rotary blood pumps that are not encumbered with mechanical bearings and magnets requiring sensors or electrical power. However, such pumps have so far needed very small and accurately manufactured gaps between rotor and housing to assure effective hydromagnetic bearing behavior. In order to use this concept in disposable pump heads, a design that allows larger rotor-housing gaps, and thus larger manufacturing tolerances, is needed.