Machine flexibility key in sorting different types of leafy greens

The two main goals of vegetable processing, food safety and product quality, are sacrosanct — but the goal posts keep moving.

When a different batch of leafy greens comes rolling down the line, processors often have to recalibrate their machines to detect different types of defects and achieve different quality grades. This complicates the day-to-day business of processing, but there can be no excuses: no matter how much or how often circumstances change on the processing line, product imperfections have to be detected and ejected.

During years of frontline experience working closely with processors, TOMRA Food’s sorting machines have been developed to deal with such variables. As a result, today’s sorters are amazingly flexible. One reason for this is sophisticated software programs, which have pre-programable machine controls. Another reason is the wide-ranging technologies employed by sorting machines, which enable an equally wide range of specialized functionalities.

On the software side, the programs that run sorters’ automatic functions can also be manually pre-set by operators via touchscreen controls. This facility enables the machines’ detection and rejection parameters to be easily and precisely tailored to each new batch of produce coming down the line, minimizing downtime between batches as well as maximizing yields.

Another benefit of sophisticated software is that the machines are getting more intelligent. A good example of this is the web-based platform TOMRA Insight. This turns sorters into connected devices that generate valuable data, then processes the data into actionable information. Another feature is SCADA (supervisory control and data acquisition) systems, which connect sorters to a control centre where fault-alerts are flagged-up immediately and can be responded to remotely. These developments herald the arrival of a new era of machine networking and self-learning which will further enhance sorting efficiencies.

Then there is the hardware, the machines themselves. Developed and configured for different purposes, these are capable of handling all manner of sorting tasks from one end of the processing line to the other. This versatility is made possible by diverse defect-detection technologies: pulsed LED light sources, high-resolution cameras, near-infrared cameras, and lasers are all deployed by today’s sorting machines, sometimes independently, sometimes in combination, depending on the designated task.

One sorter particularly well-suited to leafy greens is the TOMRA 5B, a state-of-the-art machine which is used on the processing line both before and after the washer. As the greens move along the machine’s belt, produce imperfections and foreign material (including insects and potentially toxic weeds) are detected by anything from on-belt and off-belt inspection cameras and a laser. The cameras provide a complete view and are capable of detecting defects as small as 1 millimeter. The off-belt laser, which operates with six receivers and four lasers, detects up to 99% of foreign material.

The TOMRA 5B’s exceptional sorting efficiency is further enhanced by TOMRA Insight and the powerful graphical user interface TOMRA ACT. TOMRA ACT simplifies the operating process through intuitive touchscreen tools and allows operators to see critical sorting information and real-time process data at a glance. This means that fast adjustments are possible at any time, so that the operator is always in control and can quickly optimize the sort.

The TOMRA 5B and other sorters in TOMRA Food’s wide-ranging portfolio enable processors of leafy greens and many other types of vegetable to tackle varied sorting tasks by deploying varied technical solutions.

— By Alain De Puydt, area sales manager, TOMRA Food