Sensor-based sorting without compressed air

Automatic, sensor-based bulk material sorters are used as standard in many manufacturing processes, for example in the food, raw materials, building materials and pharmaceutical industries. Energy and cost-efficient systems with high mass flow rates are of growing importance, especially in the fast-growing recycling industry.

State of the art

In sorting systems, the bulk material to be sorted is usually moved past optical sensors via a conveyor belt or chute for classification, usually by line-scan cameras or hyperspectral cameras. Objects to be sorted out are immediately deflected by compressed air blasts emitted from several adjacent nozzles. Such pneumatic separation systems are characterized by high compressed air consumption, which causes immense operating costs.

Technology

Researchers at the Chair of Intelligent Sensor-Actuator Systems (ISAS) at KIT have developed an optical sorter with a new type of discharge system that significantly increases the efficiency of sorting systems for bulk materials. An area-scan camera first detects the scattered particles of the bulk material. The camera is arranged in such a manner that it observes and classifies both the mass flow and the integrated actuators, e.g. simple mechanical flaps or tappets. The actuators are not positioned in a row as before, but as an array in a two-dimensional, slightly offset arrangement and can be actuated individually. This results in several opportunities for discharge within the camera's field of view and thus maximizes sorting success. Tracking the particles during the entire sorting process ensures a high level of control reliability. An intelligent algorithm decides which actuators are activated for the best possible sorting result.

Advantages

The sorting system developed convinces with a combination of high throughput, high sorting quality and freedom in the implementation of the discharge mechanism without compressed air. Compared to conventional sorters, the two-dimensional design allows the selective control of the individual actuators. In comparison to mechanical actuators arranged in series, the throughput can be significantly increased due to the redundancy in the system. In addition, the new system can be easily scaled by the size, number and arrangement of the actuators.

Options for companies

KIT is looking for interested parties in the field of optical sorting systems and mechanical process engineering for the industrial design of a sorting system.