Abstract: A fluid filter is designed primarily but not exclusively to filter spent fluids which may contain particulate contaminants. The filter has an assembly which may be slid into or out of a canister housing for manufacture, repair, or replacement. The assembly is a stack of porous filter media separated by perforated metal plates. The metal plates may be arranged in sets, comprising positive and negative electrostatic plates followed by magnetic plates. Or, the metal plates may be arranged in a sequence tailored for the electrical conductivity of a given fluid. A pair of rod electrodes are threaded through holes in the various plates and porous filter media. One rod electrode is connected to all positive plates. The other rod electrode is connected to all negative electrostatic plates.

Abstract: A filter for removing finite particles from a fluid is comprised of a plurality of magnetic perforated plates, negatively, electrostatically charged, perforated plates, and positively, electrostatically charged, perforated plates with filter media disposed between the plates. The plates are disposed in succession in the path of fluid flow. The fluid flows through the perforations in the plates, and finite particles are removed therefrom by the interaction of those particles with force fields generated by the plates. Particles are further removed from the fluid by the action of the filter media. Also, a system control prevents any fluid from passing through the filter when an insufficient charge is present on the electrostatically charged plates.