Issue link: https://www.e-digitaleditions.com/i/1212417
36 / March 2020 powderbulk.com As with most vacuum conveying and support equip- ment, including pre-engineered systems, bag-dump stations have the ability to be modified or enhanced. For instance, if material isn't free-flowing, then a screw discharger may be added to the bag-dump station to help move the material into the conveying line. The ability to modify or enhance pre-engineered systems came to fruition when the same toll blender needed a solution for a new customer's blended mate- rial that seemed impossible to convey into bulk bags. The solution to getting the clay-like material to convey into bulk bags was a system that included fitting a pickup hopper into the space where fiber bins normally sat. The pickup hopper was equipped with a free-flow- ing screw discharger designed to handle sticky powders. From the hopper, the material was metered into the conveying line that led to a vacuum receiver where it was discharged into a bulk bag loading station and then released into a fresh bulk bag. Adapting equipment to business needs Challenging powders sometimes need custom solu- tions, but even when powders behave well with systems, the necessity to customize pre-engineered vacuum conveying systems can arise from business growth and automation needs. When steady development at a thermal spray coat- ing manufacturer necessitated moving to a large-scale mixer to stay ahead of orders, the company needed to find a way to load six 160-pound barrels into a blender 6 or 7 feet off the ground. After years of manually load- ing small 160-pound batches into a 55-gallon rotary drum mixer, the manufacturer knew that the new sys- tem had to be automated. After researching automated systems of material delivery to blenders, the coating manufacturer chose a pre-engineered direct-charge blender loader. In addition to loading the blender, the spray coating man- ufacturer also wanted a conveying system to transfer finished product from the blender into boxes all while staying within a specific budget. Rather than purchasing two vacuum conveying systems — one to convey material into the blender and another to move blended material from the blender into packages — a dual-purpose system was proposed. A dual-purpose system, like the one shown in Figure 4, uses the same conveyor system to load and unload the blender. After materials are blended, the same vacuum conveying system used to load the blender is con- nected to the bottom of the blender, and the material is metered by volume into a collection hopper. When the hopper reaches a predetermined level, the system stops conveying and dumps the material into a box. so the company added a bag-dump station, like the one in Figure 3, that fed material into the direct-charge blender loading system. This addition allowed opera- tors to lift bags onto the bag-dump station grate, cut a slit in the bag, and then turn the bag over so that the material would fall by gravity into the conveying line. Ergonomic bag-dump stations reduce spillage during bag loading by using negative pressure to suck fugitive dust into the system before the dust has a chance to enter the air around the operator and plant environment, reducing housekeeping costs, material loss, and risk. FIGURE 3 A bag-dump station allows material to fall by gravity into the conveying line. FIGURE 4 As the name suggests, a dual-purpose direct-charge blender loading system can be used to both load and unload the blender.