Powder Spray Booths

4 Service Reports; inefficiency, filter clogging/blinding, filter cake destruction, oil on filters.

Project in Michigan The system involved coating parts with a PVC Powder. The complaint was that the dust was bleeding through the filters even after 89 hours of operation. We diagnosed the problem that during the pulse cleaning action the cake was also being blown off the media. Our solution was to build a filter cake below the surface that would not be blown off. We fed 1 ounce of baking soda per 100 square feet of filter media which required two hours of hand feeding. This stabilized the pressure drop at 2-3inches and five years later the filters were still operating perfectly with no further bleeding
Project in Northern Ohio Customer has an electrostatic powder paint coating. The booth supplier built his own collector by copying existing designs. The pressure drop was 7 inches water gauge and the volume was insufficient to keep dust from entering the room. We modified the cleaning system to increase flow through the cartridge filters. The pressure drop went to only 2 inches water gauge. Then they installed a shut off damper at the exhaust fan to lower flow and reduce horsepower requirements at sufficient flow.
Project in Antwerp Holland They were using electrostatic booths to coat grating and a bag dust collector. There was serious leakage through the filter-bags. We stopped the leakage by using duct tape on the bottom of the bag cages. The pulse-jet must clean the whole bag evenly. If a solid impermeable stop is not placed at the bottom of the cage the filter cake will be destroyed and dust will bleed through the bottom after each pulse. We remedied the situation in less than an afternoon. The manufacturer changed his design to prevent the leakage.
Project in Cleveland Ohio Machine was designed to remove rust and add coating to wire hangers provided to dry cleaners to hang cleaned clothes. Dust went right through the filter bags even though the pressure drop was less than 3 inches water column. Much of the dust consisted of pieces of scale that were bigger than fifty microns. This was much bigger than the biggest holes in the media.  After investigating we found that the trouble was because of an improper installation of the rotary screw compressor. The installer left off an oil trap that recirculated the oil through the screw. This oil coated the bags and lubricated the fibers so that dust larger than the openings in the bags was able to slide through. We had them install the oil trap and install new bags. They paid for the service call including installing new filter bags. The collector ran with the new bags for several years.

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