Sealless heart pump

Claim 1

A blood pump for pumping blood through a living body, the blood pump comprising: a housing having an inlet and outlet in fluid communication with a chamber defined therein, the housing including a portion that extends axially inwardly into the chamber; an annular pump rotor received in the chamber around the housing portion for selective rotation relative to the housing for pumping blood from the inlet to the outlet, the pump rotor being spaced from the housing and housing portion to define radially spaced first and second passages, respectively; means for rotating the pump rotor relative to the housing; means for urging blood flow through the first passage; the second passage being narrowed at first and second ends for defining circumferentially continuous fluid bearings that support the pump rotor during pumping operation; first and second helical grooves axially spaced on the housing portion at the narrowed first and second ends of the second passage to increase blood flow through the fluid bearings; means for urging blood flow through the second passage in a direction independent from blood flow through the first passage; and an opening through the pump rotor for connecting the first and second passages to permit blood flow therebetween.