Ultrasonic sensors excel in a meat bin wash-line

A meat-processing plant uses Contrinex’s ultrasonic sensors for non-contact presence checking to increase productivity and eliminate breakdowns when washing empty meat bins. A single ultrasonic sensor, mounted above the conveyor on which the bins travel, checks for meat residues, rejecting any contaminated bins before the automated wash station. Old, contact-based systems were unreliable, resulting in breakdowns and frequent interruptions to the washing process.

Application

During production, an industrial meat-processing company conveys meat portions around its factory in food-grade plastic bins. After completion of each batch, the empty bins are washed prior to reuse. However, some bins can contain sizeable pieces of meat which, if undetected, accumulate in the washing machine, causing blockages and breakdowns. The resulting interruptions to production are unacceptably frequent.

A reliable sensor system must detect the presence of meat residues in 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 system should require little or no regular maintenance, and a non-contact sensor, suitable for a hygienic environment, is preferred.

Old systems with spring-loaded wand-actuators in contact with the box are unreliable and require regular adjustment and the contact probes need frequent, time-consuming cleaning. The ultrasonic sensor-based system has to operate on a fit-and-forget basis.

Solution

Contrinex ultrasonic sensors are ideal for presence and level-sensing applications, and a diffuse sensor from the Compact range (housing size M30) is an excellent choice for this application. The operating range for this metal-bodied, IP65-rated device is between 20cm and 130cm and detection is independent of the target’s colour, shape, material or surface structure. Contrinex’s compact ultrasonic sensors feature an integral M12 cable connector, allowing rapid disconnection and removal when required. The sensor’s three-wire normally-open output communicates directly with the customer PLC. On detection of a contaminated box, a mechanical diverter shunts the box to a separate conveyor for manual emptying.