Ultrasonic sensors provide reliable meat detection on bin wash line

When a meat-processing company needed a solution to check that bins at the plant are empty before washing, it turned to Contrinex. The high performance and reliability of Contrinex’s ultrasonic sensors enabled the plant to increase its productivity and eliminate breakdowns when washing empty meat bins.

The company conveys portions of meat around its factory in food-grade plastic tote bins. Between batches, the empty bins must be washed before reuse, however, some bins can still contain sizeable pieces of meat. If this meat is allowed to remain in the tray and enter the wash station, it can accumulate in the washing machine, causing blockages and breakdowns.

To prevent this, a sensor system must reliably detect the presence of meat residues in the bins as they travel along the conveyor. The sensor should identify all non-trivial residues and divert contaminated bins before they enter the washing station. The ideal system would require little or no regular maintenance, and ideally be mountable some distance away to enable easy cleaning and be suitable for a hygienic environment.

The previous system was unreliable, resulting in breakdowns and frequent interruptions to the washing process. It employed spring-loaded wand-actuators in contact with the box, but was unreliable and required regular adjustment and the contact probes need frequent, time-consuming cleaning.

An ultrasonic sensor-based system offered the potential to work on a fit-and-forget basis. Contrinex ultrasonic sensors are ideal for presence and level-sensing applications, and this application uses an M30 diffuse sensor. The 20 to 130cm operating range of this metal-bodied, IP65-rated device is ideal because detection is independent of the target’s colour, shape, material or surface structure.

An ultrasonic sensor is mounted above the conveyor, looking down at the bins on a conveyor as they travel towards a wash machine. The sensor checks for meat residues, rejecting any contaminated bins before they can reach the automated wash station. On detection of a contaminated box, a mechanical diverter shunts the box to a separate conveyor for manual emptying.