Development of a Compact Maglev Centrifugal Blood Pump Enclosed in a Titanium Housing

Abstract

A compact centrifugal blood pump consisting of a controlled two-degrees-of-freedom radial magnetic bearing and a brushless DC motor enclosed in a titanium housing has been developed for use as an implantable ventricular assist device. The magnetic bearing also supports axial and angular motions of the impeller via a magnetic coupling. The top housing is made of pure titanium, while the impeller and the stator are coated with pure titanium and Ti-6Al-7Nb, respectively, to improve the biocompatibility of the pump. The combination of pure titanium and titanium alloy was chosen because of the sensitivity of eddy current type displacement sensors through the intervening conducting wall. The dimensions of the pump are 69.0 mm in diameter and 28.5 mm in height. During a pump performance test, axial shifting of the impeller due to hydraulic forces led to variations in the rotational positioning signal, causing loss of control of the rotational speed. This problem was solved by conditioning the rotational positioning signal. With a flow rate of 5 l/min against a head pressure of 100 mmHg, the power consumption and efficiency of the pump were 5.5 W and 20%, respectively. Furthermore, the hemolysis of the blood pump was 43.6% lower when compared to that of a commercially available pump.

Surface Coatings for Rotary Ventricular Assist Devices: A Systematic Review

“…Here, the included publications all showed it could significantly reduce platelet adhesion as compared with noncoated counterparts in in vitro studies. 54–56 For other coatings like amorphous carbon, 23 PEO, 27 GP IIb/IIIa receptor inhibitor, 45 silicone, 46 polyurethane, 47 Ti, 48 Ti6Al7Nb, 48 and apatite, 49 their hemocompatibility was investigated in a very limited number of publications. In the publication of UNCD, 7 the author did not investigate the hemocompatibility but gave the information by citing other publications which showed UNCD was antithrombogenic.…”

Estimation of the radial force using a disturbance force observer for a magnetically levitated centrifugal blood pump

“…Movements in the radial X and Y directions are controlled independently, without interference between each direction, so one-degree-of-freedom motion, in the X direction, is used in the following discussion. The impeller displacement signals are fed back by two eddy current-type displacement sensors (PU-03A, Applied Electronics Corp., Kawasaki, Japan), located between the electromagnets, to the controller of the MB [9,10]. A feedback controller is used to maintain the geometric centre of the impeller at the centre of the CBP, with vibration amplitude of 20 mm in continuous flow at 1700 r/min.…”

“…In the present authors' laboratory, a maglev CBP was developed to be used as an implantable ventricular assist device. It consists of a two-degrees-offreedom radial controlled MB and a built-in brushless d.c. motor [9,10]. The radial motion is controlled using two pairs of electromagnets and two displacement sensors, while the axial and tilt motions are passively supported by the magnetic coupling generated between electromagnets and the rotor.…”

Fifteen years of the first Brazilian Centrifugal Ventricular Assist Device for long term Mechanically Assisted Circulatory Support

“…But the fact is that several parallel projects, within the IDPC, USP, and even in the Instituto Federal de São Paulo (IFSP) were born from that interaction, such as the electromagnetic suspension for a fourth generation of CFVADs (38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51).…”