Radial Magnetic Levitation and Its Application to Density Measurement, Separation, and Detection of Microplastics

This work describes the development of radial magneticlevitation(MagLev) using two radially magnetized ring magnets to solve the problemof limited operational spaces in standard MagLev and the major shortcomingof a short working distance in axial MagLev. Interestingly and importantly,we demonstrate that for the same magnet size, this new configurationof MagLev doubles the working distance over the axial MagLev withoutsignificantly sacrificing the density measurement range, whether forlinear or nonlinear analysis. Meanwhile, we develop a magnetic assemblymethod to fabricate the magnets for the radial MagLev, where multiplemagnetic tiles with single-direction magnetization are used as assemblyelements. On this basis, we experimentally demonstrate that the radialMagLev has good applicability in density-based measurement, separation,and detection and show its advantages in improving separation performancecompared with the axial MagLev. The open structure of two-ring magnetsand good levitation characteristics make the radial MagLev have greatapplication potential, and the performance improvement brought byadjusting the magnetization direction of magnets provides a new perspectivefor the magnet design in the field of MagLev.