Methods are used to capture overspray during powder coating
Three basic methods are used to capture over sprayed powder coating powder:Cascade (also known as a water wash),Baffle, and Media filtration.
Many modern high volume spray booths incorporate one or more of these methods of source capture in an effort to improve overall removal efficiency. One of the most common combination systems, is a cascade style booth, with multi-stage media filtration, prior to the exhaust stack, or prior to a VOC control technology like an RTO (regenerative thermal oxidizer).
Anyone that looks behind the filters of a spray booth on a regular basis can probably relate a horror story or two about the condition of the plenum, stack and fan, especially booths used in high volume coating operations. The sight of all this equipment coated with paint means several things have occurred.
First, we know the fan is not operating at maximum output.
Second, we know that the exhaust capability of that spray booth is no longer meeting the air flow requirements as originally specified.
Somewhere in the past, the paint arrestors failed to achieve the required removal efficiency, or the type of coating material changed, or the operator removed a few loaded filters from the frame to keep painting until the next shift, etc. It seems as if the reasons are infinite.