Coating booth for applying a coating powder to the surface of workpieces

Coating booth for applying a coating powder to the surface of a workpiece, the powder being directed to the workpiece via an air stream comprising:

• a coating zone having a floor;
• a clean-gas zone;
• a rear wall between said coating zone and clean-gas zone;
• a filter assembly mounted in said rear wall and disposed between said coating zone and clean-gas zone;
• a suction device for exhausting air in the booth from said coating zone through said filter assembly and said clean-gas zone, said clean-gas zone being downstream of said coating zone and filter assembly with respect to the flow of air;
• said filter assembly comprising a rigid framework and a plurality of filter elements removably and substantially vertically mounted in said framework, each filter element comprising a surface membrane filter having an air-permeable support layer and a surface membrane of flexible and elastically deformable material attached to at least the upstream side of said layer, said surface membrane having a plurality of elongated perforations therein;
• cleaning means in said clean-gas zone for periodically cleaning said filter elements during the coating operation by pressure impulse;
• a powder container below the floor of said coating zone;
• and
• clearing means in said coating zone for clearing excess powder from the floor of the coating zone by moving said excess powder to said powder container.