STORY-TRÅD·industri

BHS advances autonomous recycling through integrated sorting technology

A highly automated manufacturing operation can run around the clock, spreading the cost of its equipment across more production hours and greater output. Recycling facilities have traditionally operated differently, with people still playing an important role in monitoring material, adjusting the process, and making sorting decisions. BHS CEO Steve Miller sees a future where all recycling operations move to that level of full autonomy. "Our vision is to have fully autonomous processes, sort of ‘lights-out sorting,' where the system operates independent of activity on the ground, deliveries of material, that kind of thing," Miller says. Getting there requires more than automating individual sorting tasks. Equipment has to accurately identify and separate material, but the information generated in that process also has to extend beyond a single pick or ejection. Greater autonomy depends on technologies across the sorting process sharing that information so the system can respond to what is moving through it. BHS is working toward that goal by bringing together technologies developed across its portfolio, including optical sorting, artificial intelligence, robotics, and controls and automation. Improving optical sorting accuracy with in-flight detection Long before AI became part of the recycling industry's technology conversation, optical sorting was already automating a fundamental task: identifying a target material and removing it from the stream. A successful sort, however, depends on more than correctly identifying that material. In a conventional optical sorter, there is a physical distance between where an object is detected and where it is ejected. The system has to track that object as it travels between the two points and trigger the right air nozzle at precisely the right time. That creates an opportunity for error. An object can shift laterally on the conveyor or travel slightly faster or slower than expected before it reaches the ejection point. Even if the sorter identified the material correctly, the air jet can miss its target or eject other material along with it. National Recovery Technologies (NRT), BHS's optical sorting technology brand, developed its patented In-Flight Sorting technology to reduce the potential for tracking error between detection and ejection. "What NRT optical units do that's different is they recognize the material after it leaves the belt," Miller says. "We process that reading at very high speed within milliseconds, and then we make an ejection while it's in flight." By moving the detection point off the conveyor, the system reduces the opportunity for the material's position to change between the moment it is identified and the moment the air nozzle fires. Detecting material in flight also addresses another challenge: keeping the optical sorter calibrated. Dust, changing lighting conditions, and other factors can affect optical detection when the conveyor belt forms the background against which material is being analyzed. Miller says conventional systems therefore require periodic calibration. With NRT's approach, he says the system automatically calibrates as it detects objects in flight. "Since In-flight Sorting uses a different background than the competition, our design can auto-calibrate, and so our equipment stays calibrated," Miller says.