Smart Molding International 1-2022

35 peripherals & automation www.smart-molding.com After the mixer receives a dose of powdered additives from a loss-of- weight hopper above, a valve stops the flow and the mixer makes a pre - set number of revolutions. When called for, liquid additions are pumped through spray nozzles onto a wide bed of moving material within the mixing vessel. At the end of the batch cycle, the mixer’s discharge gate opens while the vessel is still rotating. This allows the mixing baffles to guide the batch toward and through the discharge gate with little or no residual. “They do a good job of moving the material quick - ly and efficiently,” Block says. “If we’ve got a straight dry material, there isn’t much to clean out.” The gentle mixing action is critical, Block says, because it preserves prod - uct quality. “We get a good thorough blend but we don’t degrade the prod - uct. If we used a typical paddle mixer, we would grind the granules against each other and create dust. That doesn’t happen here.” Continuous rotation of the drum during discharge prevents stratification of ingredients having disparate sizes, shapes and bulk densities, and empties the batch rapidly in a steady stream. “That’s important because it minimises wait times at the packing stations,” Block says. “Because of that quick discharge, we are more efficient when packing bulk containers.” “We’ve made the same product as a 2,268 kg order and as a113,398 kg or - der,” Block says. “And blending is just as uniform on short runs as it is across larger ones,” Block says. The mixing flights also create a dy - namic bed of material, ideal for incor - porating liquid additions. “We get a good consistent dispersion. The prod - uct doesn’t get too wet in some parts and less wet in other parts,” Block says. “A typical paddle mixer would give us a less even coating.” Since their installation in 1983, the mixers have rarely been idle. Over the last 12 years, one mixer has had 34 hours of downtime and the other just 4.5 hours. “The longevity of the machines is a testament to my predecessors, who selected them,” says Block. “We’ve been pleased with the lack of down - time and maintenance costs. They’re quality pieces of equipment and just plain reliable.” Munson Machinery www.munsonmachinery.com The hinged access doors at either side of the vessel provide access to all material contact surfaces for cleaning and visual inspection Continuous rotation of the drum during discharge prevents stratification of ingredients having disparate sizes, shapes and bulk densities, and empties the batch in a steady stream