Leakage From Dust Collector Outlet

Equipment: Cartridge Collector with cellulose Media, 8 pleats per inch.

Application: System designed to coat outside surfaces of gloves with starch to keep them from sticking together. It was effective and was meant for surgical use. The coating readily fell off the gloves when they were worn and before they were put to use.

Observations: The starch dust was very coarse in the 5 to 10 micron size. The dust would easily fall from the fingers when squeezed and moved together. When the system pulsed large puffs of dust were observed at the collector outlet. We examined the dust under the microscope and it was uniform in size in the 5 to 10 micron range. However, the surface of the dust particle spheres were very smooth, almost polished. The collector ran with less than one inch pressure drop across the media, the same pressure drop as a clean cartridge. The lack of the ability to interlock the dust to form a cake meant that, during pulsing, the dust would tumble and could not agglomerate and this allowed the dust to penetrate the media during and after a cleaning cycle. The collector exhaust was returned to the work space, dust and all.

Recommendations, action, remedy and conclusions.We recommended adding a small amount of ordinary cornstarch into the collector on an intermittent basis, once every four hours. This ordinary powdered (non-spheroidal) starch formed a stable filter cake and the collector ran at 2 inches of pressure drop across the media, solving the penetration problem. The contaminated starch collected from the hopper was then sold for animal consumption but it was not a significant cost for the process. Another solution was to use a standard tubular shaker collector with laminated (Gortex) media which does not require interlocking dust to form a cake.

This approach is suitable for other dusts that do not form granulated powders that don't interlock to form a cake. Another example of this kind of dust was on a process where names were engraved on plastic. There was no granulated dust. The laminated media on cylindrical bags allowed the exhaust to be re-circulated.

For assistance with such problems ... Dust Collection Solutions