Back to results
US 5,112,200 AGranted
Hydrodynamically suspended rotor axial flow blood pump
AssigneeNu-Tech Industries, Inc.
InventorsMilton S. Isaacson, Anthony P. Lioi
Life of this patent
Estimating the term…
Abstract
A brushless DC motor has a rotor with impeller blades mounted thereon to pump blood through the central portion of the motor. Over a portion of its length, the rotor has a cylindrical surface that is spaced from a cooperating cylindrical surface on the motor stator. There is a gap between these cylindrical surfaces through which there is a leakage flow of blood. The relative motion between the cylindrical surfaces provides a hydrodynamic bearing that suspends the rotor in the stator.
Claims12
A brushless DC motor and blood pump combination comprising:
- a sator having an axial cylindrical bore, said stator having windings and a control circiut to create flux in the said bore,
- a cylindrical rotor disposed in said bore and having permanent magnets spaced around its perimeter to interact with said flux to rotate said rotor,
- a gap of about 0.008 inch said rotor and said stator,
- said rotor having a central axial passageway for the passage of blood, impellers mounted on said rotor in said passageway to pump blood through said passageway as said rotor rotates,
- the relative motion between said rotor and said stator causing a pressure distribution in the blood within said gap that supports said rotor, thus forming a hydrodynamic bearing between said rotor and stator.
2 more elements
A motor/blood pump combination comprising:
- a stator having a bore,
- said stator including a central cylindrical hub within said bore,
- radial vanes fixedly connecting said hub to said stator at each end of said hub,
- a cylindrical rotor surrounding said hub and disposed within said bore,
- said rotor having permanent magnets and said stator having windings and a circiut to create a brushless DC motor,
- impeller blades on said rotor to pump blood between said rotor and hub,
- and gaps between said hub and rotor and said rotor and stator through which said blood flows to provide hydro-dynamic bearings between said rotor and stator, and said rotor and hub,
- the pressure distribution in said gaps being generated by the relative motion between said rotor and said stator, and
- the pressure differential being generated axially across said rotor generted by the action of the impleelers,
- both pressure distribution and differential causing a leakage flow of blood through said gaps at a rate sufficient to prevent significant damage to blood cells from shear stress.
7 more elements
Dependencies are inferred from the claim text.