The ultimate objective of this program is to develop a hydrodynamic thrust bearing for use in a range of continuous flow implantable rotary blood pumps. Development and integration of the MiTi"""""""" hydrodynamic thrust bearing into rotary blood pumps such as the proposed MiTi"""""""" centrifugal blood pump will enhance overall reliability of this life support system and will result in a compact low power consumption continuous flow pump. Key elements of the proposed program include 1) a detailed integrated blood pump and hybrid bearing system design including permanent magnet radial bearings and the combined active magnetic and passive hydrodynamic thrust bearings; 2) component bearing testing to validate the design and freedom from hemolysis; 3) fabrication of up to three prototype pumps; 4) in-vitro testing of the pump; and 5) preliminary in-vivo studies. In-vitro testing will validate pump and bearing performance, verify that washing flows limit deposition, and verify the lack of hemolysis damage to the blood circulated through the pump. In-vivo testing is planned to demonstrate freedom from deposition related difficulties with the rotor dynamic pump. Key features of the blood pump include only one actively controlled magnetic bearing axis with an integral hydrodynamic thrust bearing for reliability and simplicity, replacement of conventional displacement sensors with self energizing velocity sensors; large clearances throughout the pump that minimize blood shear stresses and promote good forward washing flows.
|Ren, Zhaohui; Jahanmir, Said; Heshmat, Hooshang et al. (2009) Design analysis and performance assessment of hybrid magnetic bearings for a rotary centrifugal blood pump. ASAIO J 55:340-7|