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.
Whatever your role in the potato value chain—key decision-maker, chief executive officer, technical support specialist, or grower—after reading this white paper, you will understand how the FPS fulfills these requirements and why your organization will benefit from using it.
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
• 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.
This white paper was researched and written by Jorge Luis Alonso G., a writer for the fresh and processed food industries
(www.jorgeluisalonso.com), and edited by Vicki Adang, editor and writing coach (www.mmwllc.net).
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
The following sections explain how the FPS addresses
these critical issues; other benefits to using the FPS are
1. 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
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.
2. 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
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.
3. 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
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.
4. Time Saved
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.
5. Yields Increase
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.
6. 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
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
• 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
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 an
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
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
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
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
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:
1. It is hard to eject heavy or large items, like rocks,
metal, wood, and round objects like golf balls,
with compressed air.
2. Higher air flow is required to eject large
foreign matter, leading to the need for large air
compressors and significant energy consumption.
3. 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
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
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.
TOMRA Sorting Food
TOMRA Sorting Food designs and manufactures sen-
sor-based sorting machines for the food industry. Over 6,250
systems are installed at food growers, packers, and proces-
The company provides high-performance optical sorters,
graders, peeling and process analytics systems for nuts,
grains and seeds, dried fruit, potato products, fruits, vege-
tables, tobacco, meat, and seafood. The systems ensure an
optimal quality and yield, resulting in increased productivity,
throughput and an effective use of resources.
TOMRA Sorting Food is part of TOMRA Sorting Solutions
which also develops sensor-based systems for the recycling,
mining and other industries.
This powerful combination of technologies makes TOMRA
Sorting one of the most advanced providers of sensor-based
sorting solutions in the world, with over 11,300 of its systems
TOMRA Sorting is owned by Norwegian company TOMRA
Systems ASA, which is listed on the Oslo Stock Exchange.
Founded in 1972, TOMRA Systems ASA has a turnover around
€710m (2016) and employs over 3,500 people.
For more information on TOMRA Sorting Food visit
To take the first step toward improving the quality of your sort,
please call +32 16 396 396 or e-mail email@example.com.