Development of a new miniature magnetic fluid seal for a catheter-type axial flow blood pump

Abstract

We have developed a new magnetic fluid seal for an miniature axial flow blood pump that can be placed by catheterization. The new magnetic fluid seal consists of a ring-shaped neodymium magnet, iron ring and magnetic fluid. The size of the magnetic fluid seal is an outer diameter of 4 mm and length of 3 mm. The electromagnetic field analysis shows that the magnetic fluid seal has an estimated pressure-resistant of 432 mmHg. We examined its durability by an in-vitro experiment. The magnetic fluid seal has been sealing the motor from water against a water pressure of 110 mmHg at a motor rotational speed of 8000 rpm for over 120 days, and the durability test is going on. From the results, the new magnetic flow seal is a promising non-contact seal to accomplish a catheter-type miniature axial flow blood pump for long-term usage.