Electrostatic Fluidized Bed

An electrostatic fluidized bed is essentially a fluidized bed with a high voltage dc grid installed above the porous plate to charge the finely divided particles. Once charged, the particles are repelled by the grid, and they repel each other, forming a cloud of powder above the grid. These electrostatically charged particles are attracted to and coat products that are at ground potential. Film thicknesses are similar to what can be achieved in the electrostatic spray process. The advantages of electrostatic fluidized bed coating is that preheating of parts is generally not necessary and small products, such as electrical components, can be coated uniformly and quickly. The disadvantages are that the product size is limited and inside corners have low film thickness owing to the well known Faraday cage effect.