Design of a Bearingless Blood Pump

In the field of open heart surgery, centrifugal blood pumps have major advantages over roller pumps. The main drawbacks to centrifugal pumps are however problems with the bearings and with the sealing of the rotor shaft. In this paper we present a concept for a simple, compact and cost effective solution for a blood pump with a totally magnetically suspended impeller. It is based on the new technology of the "Bearingless Motor" and is therefore called the "Bearingless Blood Pump". A single bearingless slice motor is at the same time a motor and a bearing system and is able to stabilise the six degrees of freedom of the pump impeller in a very simple way. Three degrees of freedom are stabilised actively (the rotation and the radial displacement of the motor slice). The axial and the angular displacement are stabilised passively. The pump itself (without the motor-stator and the control electronics) is built very simply. It consists of two parts only: the impeller with the integrated machine rotor and the housing. So the part which gets in contact with blood and has therefore to be disposable, is cheap. Fabricated in quantities, it will cost less than $10 and will therefore be affordable for the use in a heart-lung-machine.