Norfolk firm CTM has designed a sensor system for inclusion in a potato grading line.

The system uses “intelligent” sensors which are programmed to detect and remove foreign objects such as stones, glass and metal from the line.

An in-feed belt spreads the crop across the six channels where the sensor bars are fitted.

According to the firm the sensors determine potatoes from foreign bodies on a density basis.

When the sensors are triggered a compressed air valve is opened allowing the foreign object to drop onto a waste conveyor.

CTM says that the reduction in downtime and the penalties imposed by processors for contamination should go some way to justifying the 70,000 price tag for the system.