Powder Spray Booths

Powder booths are designed to safely contain the powder over-spray. Booth entrance and exit openings must be properly sized to allow clearance for the size range of parts being coated, and airflows through the booth must be sufficient to channel all over-spray to the recovery system but not so forceful that they disrupt powder deposition and retention on the part.

There are two main types of booths. Batch booths are designed for coating individual parts or groups of parts that are handled using batch production methods. Conveyorized booths can provide continuous coating of parts hung on an overhead conveyor line in medium- to high-production operations.

Chain-on-edge booths are designed for use with an inverted conveyor featuring spindles or carriers for holding the parts. Used primarily for one-sided coating of sheet metal and similar parts of minimal thickness, flat-line booths use a horizontal conveyor that passes through the powder booth carrying the part to be coated on its surface.

Properly designed, operated and maintained powder systems can allow color changes in a matter of minutes. Booth features that facilitate color changes include non-conductive walls that repel rather than attract powder, curved booth walls to discourage powder accumulation and automated belts or sweepers that brush powder particles to the floor and into the recovery systems.

Also facilitating fast color changes are blow-off nozzles set up at each gun barrel and easily changed connections at the back of the gun outside the booth. A new approach using high-density powder and low-volume air aids in faster color change, increases transfer efficiency and provides better coverage for difficult parts while using less powder.

Powder recovery systems use either cyclones or cartridge filter modules that can be dedicated to each color and easily removed and replaced when a color change is needed. Equipment suppliers have made significant design improvements in spray booths that can allow both fast color changes with minimal downtime and recovery of a high percentage of the over-spray. The use of powder recovery technology can increase powder utilization to greater than 95%.