The effect of barrel design on drag-out

A search of the literature(1,2,4) found that there have been no independent studies comparing drag-out rates to barrel designs over the past 10 years. Meanwhile, newer barrel designs have been developed, and manufacturers of some of these newer designs have claimed significant improvements in drag-out losses.(3,5,6) Further, in the past three years, hundreds of metal finishing job-shops have entered into a voluntary agreement under the Strategic Goals Initiative (SGI), initiated by USEPA and co-sponsored by state environmental agencies, to reduce metals loading in wastes, reduce water consumption, and increase metals utilization dramatically. The Illinois Waste Management Resources Center agreed to fund a study that would produce a benchmark test to compare drag-out rates of plating, barrels. This test was used to compare a small sample of barrel designs, to illustrate the efficacy of the test and provide the metal finishing industry with guidance for reducing drag-out rates, making it easier to achieve its goals under SGI. The information can also be used by equipment manufacturers to improve the designs of their plating barrels, so that lower levels of drag-out rates can result in lower levels of pollution on a nationwide basis. The study was limited to two size ranges of plating barrels-small and large. For small barrels, (6 in. x 12 in.), testing showed that a reduction in drag-out rate as high as 48 percent may be achieved. For large barrels (16 in. x 34 in.), testing showed that a reduction as high as 44 percent may be obtained.