| DENSE MEDIUM SEPARATION -> AGRIC: CARROTS | POTATOES SUGAR |
Old Sorting Technology That Did Not Work
The story of ESR
International’s involvement in vegetable preparation began
back in 1985 in the cleaning and sorting of carrots. The
largest cannery in Belgium at that time had just about
given up all hope of isolating carrots from the endless
variety of contaminates that might surround them. Two
dynamic effect separators, followed by a sophisticated
color-sorting apparatus, followed by a group of 20 women,
all failed to deliver a clean product.
A
New Dense Medium Separator
To meet this challenge, ESR
International designed a unique bi-directional dense medium
barrel, and when it was first put in operation at this
Belgian cannery, it was hard to believe the initial
results. Not only did it remove stones and metals from the
carrots, but it also removed near-gravity extraneous
material such as corn stubble, fly ash and bits of plastic.
Even young potatoes that had sprouted from a previous
year’s harvest separated out nicely and reported in their
entirety with the stones. Within a few weeks of starting up
this new separator at this cannery, the dynamic effect
separators and the color-sorting apparatus were abandoned,
and the group of 20 women was reduced to two.
Quality
Grading of Carrots
But the biggest surprise of all was the precise separation
of a good carrot from a partially dehydrated carrot, or a
good carrot from a low-density defective carrot. Although
the difference in density between a good and bad might be
but a few points to the second or third decimal place, a
clear and faultless separation took place. Not only were
the maintenance costs associated with the processing of
trash drastically reduced, but also issues regarding the
quality, taste or texture of the carrot fell for the first
time within the processor’s control.
Suspension
Fines from Carrot Dirt
In this revolutionary
sorting process, the suspension fines needed to change the
density of water are obtained nowhere else but from the
dirt that mechanical harvesters extract along with the
carrots. Carrots are grown in sandy solids, and a
significant portion of this sand adheres to the carrot when
harvested. ESR employs two stages of classifying cyclones
to isolate this fine sand from the scrub and rinse water of
a carrot cleaning line. By using the fine sand that
accompanies the carrot into the processing facility, we
avoid the dreadful health issues associated with the use of
quarry clay or sand that might be contaminated with dioxins
or heavy metals, and we avoid as well the thorny
environmental and maintenance issues associated with the
use of salt and the disposal of brine.
European
Success
Eventually sixteen bi-directional dense medium separators
were sold in Belgium and France. The leading vegetable
processor in Europe, Bonduelle, with a colossal 30% share
of the European vegetable market, bought five separators,
all operating on carrots. Their fifth separator, recently
installed in August 2004 in Renescure, France, is the first
vegetable separator designed by ESR LLC that does not
employ vibratory screens. With sixteen separators in
continuous operation in Europe, some for almost 20 years,
it is truly remarkable that no one to this day has ever
been able to establish a single separation error in the
finished product.
Scrubber
Barrels & Rotary Screens
ESR International LLC has also designed for the carrot
industry a special scrubber barrel that rids the carrot of
adhering clay and sand. Special agitators within the
scrubber gently scrub the carrots without breaking them.
ESR has also abandoned vibratory screens for the dewatering
and rinsing of carrots. This is now done far more
efficiently by means of rotary screens (scrubber-rinsers)
that feature the underwater rinsing of the carrot.
Two Density
Separations
Typically two separations are required on carrots. The
first separator removes dehydrated carrots, stones and
other high-density debris, while the second separator
removes low-density defective carrots and debris. The good
carrot situates within a narrow density range, from
approximately 1.025 to 1.055.
The
Elimination of Fluming
With this technology, the antiquated practice of
transporting carrots by means of a gigantic flume can be
abandoned. Many processors could never let go of fluming
technology, since it is by means of the stone catcher
within the flume that stones are removed. But since the
first separator within the ESR line does a perfect job
removing stones, and since the scrubber barrel does a
perfect job removing adhering sand and clay, the flume is
no longer needed. How much easier it is to transport
carrots from one point to another by means of a simple
conveyor belt than by means of a river of water!
From 60 to
400 Tons per Hour
Certain carrot processors, especially in California, must
handle relatively large tonnages. To meet this demand, ESR
International has designed dense medium separators capable
of handling 200 and even 400 tons of carrots per hour.
Large or small, ESR International has assembled an exciting
array of technologies that enable the processor to bring to
market nothing other than the perfect carrot.