Blood pump

A blood pump having a toroidal shaped chamber concentrically positioned around a cylindrically shaped hydraulic pump. The toroidal chamber has two toroidal shaped portions, one portion having a substantially rigid external wall and the other having an external wall formed of a flexible membrane. The chamber has an inlet and output port suitable for connection to a blood flow supply. The flexible wall portion of the toroidal chamber is enclosed within a hydraulic chamber, fluidically coupled to the hydraulic pump. The hydraulic pump is controlled so that an increase of pressure in the hydraulic chamber results in a decrease of volume in the toroidal chamber, thus providing for pumping of the blood through that portion of the chamber. The toroidal shape provides for optimal non-coagulating flow, while the rigid wall of the chamber, together with the flexible membrane provide for membrane motion along only one axis, normal to the circumference of the toroid, preventing damage to the membrane. The blood flow inlet port is positioned to direct fluid in a tangential direction against the perimeter wall of the toroid.