Paint spray booth-differential downdraft control

Abstract

A paint spray cell and air plenum assembly, comprising (a) a paint spray cell having a perforate air inlet wall occupying at least a substantial portion of one side of the cell and having at least one electrostatic paint sprayer to direct charged spray particles along a desired path to a receptive target, (b) a plenum having an undivided air supply and an outlet joined to the cell inlet wall to admit the air uniformly therethrough, and (c) variable density filter media at the plenum outlet to create differential velocity flows through said inlet wall that affect paint particles differently in different locations to both optimize paint transfer efficiency to the target and reduce paint particle adherence to objects other than the target. A method of increasing paint transfer efficiency when spraying electrocharged paint particles onto an automobile panel or body positioned within a cell and through which air flow is moved to exhaust stray paint emissions, comprising (a) interposing different density filter media at different locations in the air flow through which the air must pass to effect at least high and low air velocity drafts, (b) placing (i) paint spraying equipment, and (ii) surfaces to be painted by sprayed particles generally perpendicular to the air flow, in the high velocity air flow, and (c) placing surfaces to be painted by sprayed particles, generally aligned with the air flow, in the high velocity flow.