Application of a magnetic fluid seal to rotary blood pumps

Abstract

A magnetic fluid seal enables mechanical contact-free rotation of a shaft without frictional heat and material wear and hence has excellent durability. However, the durability of a magnetic fluid seal decreases in liquid. The life of a seal applied to a rotary blood pump is not known. We have developed a magnetic fluid seal that has a shield mechanism minimizing the influence of the rotary pump on the magnetic fluid. The developed magnetic fluid seal worked for over 286 days in a continuous flow condition, for 24 days (on-going) in a pulsatile flow condition and for 24 h (electively terminated) in blood flow. The magnetic fluid seal is promising as a shaft seal for rotary blood pumps.

Failure of Magnetic Fluid Seals Operating in Water: Preliminary Conclusions

“…An opinion can be found in the scientific literature [2,8,12] that the boundary velocity can be related to interface instability which appears at certain velocity difference between the contacting fluids.…”

“…These issues are the object of theoretical analyses published in scientific and technical literature [14]. The experimental research publications [8] on magnetic fluid seals working in liquid environments confirm the effect of the magnetic field and interface stability on the seal's lifetime.…”

Multi-stage magnetic-fluid seals for operating in water – life test procedure, test stand and research results

“…The seal life diagrams for different motion speed values indicate that for each of the fluids can be observed a range of speed values below which a significant extension of failure -free operation period of the seal occurs. The process is probably associated with Kelvin -Helmholtz phenomenon of instability [2,3,11]. 7.…”

Dielectric Properties of Boron Nitride-Ethylene Glycol (BN-EG) Nanofluids

“…[16][17][18][19] In particular, Kasaeian et al, 20 Kim et al, 21 Leong et al, 22 Mahian et al, 23 and Sarsam et al 24 presented results of very extensive work on the use of nanofluids in solar energy systems. Other potential applications for nanofluids include friction reduction, [25][26][27] magnetic sealing, [28][29][30][31] biomedical applications, 32,33 electronic cooling, [34][35][36] and many others.…”