Centrifugal blood pump with impeller blades forming a spin inducer

DETAILED DESCRIPTION With the present invention, a reduction in hemolysis is achieved by positioning a plurality of blades of the impeller adjacent to the spindle which intersects the center and is the axis of rotation of the impeller.
This configuration reduces hemolysis because the velocity of the blade tangential to the axis of rotation is at its minimum at the center of the impeller.
Thus, hemolysis is reduced because the first contact of the blood with the impeller blade occurs at a point where the impeller blades have a relatively low tangential velocity with respect to the axis of rotation.
Since the blades of the present invention are positioned adjacent to the center of the impeller, the blood is slowly accelerated from a point of relatively low tangential velocity to a maximum tangential velocity which occurs when the blood reaches the outer blade end.
The present invention is a centrifugal pump for pumping biological fluids such as blood.
The pump has a housing which defines a pumping chamber.
An impeller, supported by a spindle, rotates about an axis of rotation located at the center of the impeller.
The impeller itself is disposed within the pumping chamber.
The pumping chamber has an inlet directed at the center of the impeller and an outlet provided along the periphery of the impeller.
The impeller includes a plurality of blades positioned on a first surface.
An inner end of each blade is adjacent to the spindle which supports the impeller.
A plurality of inner blade ends form a cone-shaped area, or spin inducer, around the circumference of the spindle.
The location of the spin inducer near the center of the impeller causes the blood to rotate at a relatively low tangential velocity when it enters the high flow inlet area.
The inner ends of the impeller blades, which actually form the cone-shaped spin inducer, are positioned at the center of the impeller adjacent the spindle.
The velocity of each inner blade end tangential to the axis of rotation is at a minimum.
The spin inducer is able to reduce the amount of hemolysis because the first contact of the blood with the impeller is at a point of relatively low tangential velocity