A novel dielectrophoretic oil filter

Abstract

A novel dielectrophoretic oil filter concept is introduced and proof-of-concept systems are tested. Traditional methods of dielectrophoretic separation using planar microelectrodes have a common problem: the dielectrophoretic force, which is proportional to ∇|E|2, rapidly decays as the distance from the electrodes increases. In this paper, the use of three-dimensional electrode designs for high-throughput dielectrophoretic separation/concentration/filtration systems is investigated. Three-dimensional electrode designs are beneficial because they provide a method of extending the electric field within the fluid, the three-dimensional electrodes can be designed so that the velocity field coincides with the electric field distribution, filtration of particles too small to be physically filtered is possible, and novel electrode designs, not based on planar electrodes designs, can be developed and used. The electric field distribution and velocity fields of three-dimensional electrode designs that are simple extensions of two-dimensional designs are presented, and three novel electrode designs that are not based on two-dimensional electrode designs are introduced, Finally, the experimental results are presented. Preliminary results from particle count analysis suggest that a reduction of up to 90 per cent in particulate contaminants could be achieved (the standard deviation was quite high owing to the small number of particles within view and the uneven distribution of particles within the oil).