Mj. Baloh et al., Characterization of a magnetic bearing system and fluid properties for a continuous flow ventricular assist device, ARTIF ORGAN, 23(8), 1999, pp. 792-796
This article presents the performance test results of the CFVAD3 continuous
flow blood pump in an artificial human circulation system. The CFVAD3 util
izes magnetic bearings that support a thin pancake impeller, the shape of w
hich allows for a very compact pump whose total axial length is less than 5
cm with a radial length of about 10 cm. This gives a total volume of about
275 cc. The impeller itself has 4 vanes with a designed operating point of
6 L/min at 100 mm Hg of differential pressure and 2,000 rpm. The advantage
s of magnetic bearings, such as large clearance spaces and no mechanical we
ar, are elaborated upon. Furthermore, bearing modal parameters such as load
capacity and current gains are described. These parameters in conjunction
with the operating conditions during testing are then used to estimate the
fluid forces, stiffness, and damping properties while pumping. Knowledge of
these parameters is desirable because of their effects on pump behavior. I
n addition, a better plant model will allow more robust control algorithms
to be devised that can boost pump performance and reliability.