Potato sorters used in ﬁelds today are inefﬁcient, expensive to operate, and high maintenance. Many of these machines require several people to operate them, and weather conditions must be just right for optimal sorting. Additionally, the machines fail to adequately separate foreign objects from the harvest, which reduces the yield and increases storage costs. Growers then run the risk of rejection and return from the processing plant.
TOMRA’s Field Potato Sorter (FPS) overcomes all of these issues.
The FPS is a sensor-based sorting machine for unwashed potatoes; it removes soil clods, stones, and foreign objects. The machine’s technology identiﬁes and compares the physical characteristics of good product and foreign material, and sorts based on these patterns.
To deploy a sensor-based sorting machine for unwashed potatoes, most companies have a set of essential requirements:
- A machine that classiﬁes and separates potatoes from foreign objects, regardless of the weather conditions
- Equipment that requires little or no adjustment
- Machinery with high-capacity sort
- A well-designed structure for gentle product handling
- A low-energy consumer solution
Whatever your role in the potato value chain — key decision-maker, chief executive ofﬁcer, technical support specialist, or grower — after reading this, you will understand how the FPS fulﬁlls these requirements and why your organization will beneﬁt from using it.
Seeing the benefits of the FPS
Sorting unwashed potatoes is a critical step in the potato business because the quality of the product depends on how well that classiﬁcation is done.
Growers and packers currently sort their unwashed potatoes using two kinds of sorters: optical (digital) sorters or non-optical (mechanical) sorters.
But they have two main challenges when using these sorters:
- They have to deal with inclement weather while attempting to harvest and store potatoes in the shortest possible time.
- They have to make constant adjustments to the sorter.
The following sections explain how the FPS addresses these critical issues; other beneﬁts to using the FPS are also discussed.
Weather Conditions Don’t Matter
The FPS can classify and separate potatoes from foreign objects, regardless of the weather conditions. Using its unique detection mechanism and object analysis techniques, the FPS separates potatoes from stones and soil clods, even when there is more soil adhesion because of poor weather and harvesting conditions.
Other sorters have to stop or delay the harvest during poor weather conditions. The harvesters tend to lift more soil and form more soil clods in wet conditions. This situation can cause higher foreign object loads to be included. Manual picking of this increased load means a reduction in throughput and therefore slower harvesting and, occasionally, halting work. With the FPS, which can deal with higher reject loads, there is no need to slow down or stop.
No Need for Constant Adjustments
Competitors’ sorters require signiﬁcant adjustments as ﬁeld conditions change, and it can be challenging to achieve repeatable results. Unlike these sorters, the FPS has a touchscreen user interface that provides product sorting data.
When fewer adjustments are needed, the sorting process becomes more efﬁcient. For example, only one adjustment is necessary when the soil covering the potatoes becomes very heavy. The adjustment can be made on the touchscreen without stopping the sorter. The user then sees the result of the adjustment immediately on the screen. Mechanical adjustment is not necessary. In general, an adjustment isn’t needed more than once a day.
Because the FPS needs less monitoring than other sorters, growers and packers can attend to other tasks while harvesting potatoes. They just need two minutes to check the machine’s settings each morning when starting it up.
Always Ready to Work
Growers and packers must weigh the cost to acquire, train, and retain labor against the cost of purchasing and maintaining automation technology.
With labor hard to ﬁnd, typical labor savings using the FPS is approximately 80%. You no longer need to hire staff, train them, process timesheets, check attendance, and process payroll costs. The FPS is always ready to work.
For example, a typical sorter will have four to ﬁve people working on a 60 to 70 tonne per hour throughput removing stones, clods, and foreign objects. The FPS reduces the required number of people to one or two. In the long run, the cost of the FPS is offset by the labor savings.
The number of hours you save by using the FPS depends on the ﬁeld conditions and weather conditions, but you could realize savings of up to 30%. Growers typically spend 10 hours a day on harvest and storage. With the FPS, this can be reduced to 8 hours per day.
The sorter can be used on product going into storage and out of storage, creating savings on both sides.
Rocks and soil clods can damage potatoes during long-term storage, resulting in reduced yields. The FPS increases the yield by detecting and removing rotten product and the smallest foreign objects from production lines. Exact numbers are not available to know the extent of damage caused during storage, but common estimates put the loss at up to 1% yield loss due to storage.
Poor or insufﬁcient removal of stones, soil clods, and other foreign objects leads to higher yield loss and storage costs. For example, in 6,000 tonnes of harvest, the removal of foreign objects (about 5% of the total weight) means 300 tonnes of material that does not have to be cooled for storage. The removal of this material also results in efﬁciency in storage space.
Risk of Load Rejection Reduced
Growers who provide potatoes to the processing industry seek to eliminate the risk of load rejection and return because foreign object levels exceed speciﬁcations. The FPS can reject foreign objects more efﬁciently and more accurately than human pickers, reducing the risk of rejection and return from the processing plant. Higher-quality loads are delivered to the plant.
Intuitive Graphical User Interface
Most food sorting machines contain complex sensors; any small adjustment error can signiﬁcantly affect yield and cost. To overcome that, TOMRA created the TOMRA ACT, a more intuitive and less operator-dependent sorting user interface.
Thanks to this system, the FPS’s screen provides simple controls and feedback. The touchscreen controls make it easy to get data from the sorting process and to adjust the parameters to get the results you need.
The screen allows you to see at glance:
- The machine’s rejection levels — i.e., how much rejected material is soil, rocks, and other foreign objects
- The overall throughput of the harvest (potatoes, stones, soil clods, foreign objects)
The screen updates every 5 seconds with information about the percentage of potatoes accepted and percentage of material rejected. This allows the grower to know the efﬁciency of the harvester and the quality of the loads from the ﬁeld.
The TOMRA ACT received the 2015 International Design Excellence Award(IDEA)
Instead of using conventional near-infrared (NIR) spectroscopy to detect and reject rotten potatoes and foreign objects, the FPS uses multispectral NIR sensors to scan each item in ﬂight (when the product falls from the infeed belt to the accept conveyor belt).
Using the next generation of spectral imaging — biometric signature identiﬁcation (BSI) technology — the FPS identiﬁes the material’s unique ﬁngerprint. The BSI technology illuminates every object that crosses the inspection zone and detects the object’s reﬂection. The reﬂection is then analyzed in the spectral space by a NIR sensor to determine whether the object is a potato or foreign object. TOMRA’s new inspection technology minimizes false rejections.
Even if the potato has a lot of soil on it or looks like a foreign object, the BSI module will detect it as a potato
Gentle Product Handling
All physical contact with potatoes after the harvest deteriorates their quality. This can reduce the product’s value and negatively affect the next processing steps. So, gentle handling must be a primary focus for growers and packers.
The FPS is designed to reduce the amount of handling needed to sort potatoes. As material is picked from the ﬁeld, the accepted product passes untouched through the sorter while intelligent low-wear ﬁnger ejectors reject foreign objects.
The design minimizes the drop of the potato from the infeed belt to the accept conveyor belt, which is unique in construction. The machine uses a pintle belting — a soft belting material that absorbs the impact of the potato hitting the belt to avoid damage to the product.
The removal of foreign materials such as clods, stones, and other foreign objects is crucial, not only for improving yield but also for minimizing the damage to delicate potato tubers during handling and storage.
Low-Energy Consumer Solutions
Two systems are responsible for the signiﬁcant energy efﬁciency of the FPS: the illumination and detection system and the electro-pneumatic ﬁnger ejection system.
Illumination and Detection System
Most sorters use an enormous amount of halogen lighting to do the same work of the FPS, but the FPS uses about ten times less energy because of the Flying Beam technology.
With the Flying Beam technology, the FPS has to illuminate only one spot instead of the whole region of imaging. Its scanning beam moves across the products at an extremely high speed, and it inspects potatoes and foreign material as they drop off the infeed belt.
The Flying Beam technology use up to 40 times less illumination power than other technologies and thus uses less energy and generates less heat output. As a result, the scanner does not have to be cooled as the scanners in most other sorters do.
Electro-Pneumatic Finger Ejection System
Many sorters use compressed air to reject foreign objects from the product ﬂow. Compressed air shoots through a nozzle to remove the object.
A compressed air system has several disadvantages:
- It is hard to eject heavy or large items, like rocks, metal, wood, and round objects like golf balls, with compressed air.
- Higher air ﬂow is required to eject large foreign matter, leading to the need for large air compressors and signiﬁcant energy consumption.
- Air ejection of unwashed potatoes results in signiﬁcant creation of dust, which obscures the vision system detectors.
The FPS uses an air cylinder and ﬁnger system. The compressed air shoots out through a valve at very high speed, ﬁlls a cylinder, and pushes the ﬁnger to eject the foreign material. After the foreign material is removed, the ﬁnger snaps back into its resting position, and the product ﬂow continues.
This process occurs at very high speed, so the FPS can sort rejected objects while remaining extremely energy efﬁcient.
The FPS consumes less than 6 kw/hour when sorting 70 tonnes per hour. Additionally, it uses about one-tenth of the compressed air required for an air ejection system.
TOMRA’s FPS meets all the key needs of today’s companies, including:
- A machine that operates at high capacities and provides an excellent sort, even in the harshest of environments and hot, cold, or wet weather. The quality of the harvest is always maintained.
- Equipment in which quick monitoring and fast adjustments are possible at all times. The customer is always in control of the product ﬂow and the quality of the sort.
- A sorting machine that discards a broad range of foreign materials, including stones, soil clods, corn cobs, wood, stems, plastic, glass, and even stray golf balls. This process enables users to deliver consistently high-quality products to their customers, maximizing yield and proﬁt while reducing potato waste.
- A tool designed to ensure gentle product handling, thus reducing the mechanical damage to delicate potato tubers.
- A solution that minimizes energy usage.
- A machine that allows growers to store potatoes with fewer stones and clods. If storage losses are minimal, storage costs will be minimal.
To take the ﬁrst step toward improving the quality of your sort, please call +32 16 396 396 or e-mail firstname.lastname@example.org
TOMRA Sorting Food designs and manufactures sensor-based sorting machines for the food industry. Over 6,250 systems are installed at food growers, packers, and processers worldwide. More about TOMRA: www.tomra.com/food