Electrostatic powder coating installation

An installation for applying an electrostatic powder coating of different colors to workpieces, comprising:

• a cabin having longitudinally extending side walls, end walls and a bottom portion, each of said end walls having an opening for passing workpieces into said cabin, an interior side of said walls and bottom portion being formed of a relatively non-stick, electrically non-conductive material and formed to be essentially free of any powder trapping discontinuities, said bottom portion comprising a smoothly varying generally V-shaped transition region extending longitudinally along the cabin;
• a collecting channel extending along said bottom portion and having a variable width opening therein, said opening communicating with said transition region;
• a suction device connected to said collecting channel, the width of said variable width opening being generally proportional to a distance of the opening from the suction device to obtain a generally uniform suction speed from the front to the back of the cabin;
• a cleaning device formed to compliment the internal contours of said cabin;
• means for moving the cleaning device through said cabin whereby the amount of powder clinging to the walls of the cabin is reduced and the interior of the cabin is easily cleaned of any residual powder.