Special Topic: Application of Electromagnetics for Mechanical Circulatory Support Devices
A Magnetic Fluid Seal for Implantable Blood Pumps: Structure for a Long Life
2019 Volume 27 Issue 3 Pages 280-285
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2019 Volume 27 Issue 3 Pages 280-285
A magnetic fluid (MF) seal enables mechanical contact-free rotation of a shaft and hence has excellent durability. The performance of an MF seal, however, decreases in liquids. We developed an MF seal that has a ‘‘shield’’ mechanism. Factors limiting the seal life and their solution methods were studied. Factors limiting seal life were MF flowing away and mixing of MF with liquids. Two types of shield were placed in MF seals installed in rotary pumps. Long-term durability tests were conducted. The MF seal with a small cavity space shield showed a longer life (116+ days, ongoing) while the MF seal with a large cavity space shield failed after 28, 31 and 30 days. The use of an optimally designed-shield prolongs an MF seal life by preventing the MF from flowing away and mixing with liquids.
