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The following case histories from the food and mining industries demonstrates the
benefits of the Van der Graaf drum motor.
Food Industry - Cocoa Beans,
Meat Processing, English
Walnuts
Mining Industry - Coal
Food Industry - Cocoa Beans
Van der Graaf drum motors run continuously in chocolate
plant's harsh and dusty conditions, reducing maintenance considerably.
 Blommer
Chocolate Mills of Greenville, PA processes nearly two million pounds of cocoa beans
every week. They operate three shifts a day, six days a week, year round. Incoming
beans are received by rail car or over-the-road bulk trailers and stored in five
large silos. The beans, as received, are saturated with abrasive dust - hard on bearings.
The first cleaning stage screens them to remove any remaining sticks, stones, pieces
of pod and stems. The conveyors must operate continuously in the harsh, dusty conditions.
As the beans are released from the storage silo, they are transported through the
screening/cleaning process and then on to the roaster by the hardest working conveyors
in the plant. These units are powered by Van der Graaf drum motor pulleys. Terry
Grill, Plant Engineer, says, "We have had zero downtime in over 8 years of using
the Van der Graaf pulleys! The dependability factor is an unexpected bonus. We initially
chose the internally driven, so-called drum motor pulleys because of the tight quarters
where our conveyors must operate. In the early days of this operation we used the
old style, shaft mounted gearmotor or gearmotor roller chain and chain safety cover.
Van der Graaf motorized pulleys are a standard specification item for our systems
now."
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Food Industry -
Meat Processing
Pork processing plant raises production with drum
motors.
 Hatfield
Quality Meats processes 6,000 hogs per day in the ultramodern and highly automated
750,000 square foot plant they opened in 1991. Dependability, safety and sanitation
are the standards of equipment operation in the Pennsylvania company.
Dick Feldkamp, Manager of Industrial Engineering said, "We chose Van der Graaf
motorized pulleys over others we tested because their seals held up the best under
high pressure washdown (700 PSI plus detergent). Our choice has been right - we have
had zero downtime."
Hatfield uses approximately 25 Van der Graaf drum motors on their busy cut floor
lines and on their sortation conveyors. This pork processing facility uses the stainless
steel Van der Graaf drum motor pulleys in conjunction with sanitary, hinged white
plastic belts which use sprocket drives. Van der Graaf provides special self-aligning,
floating sprocket mounts for powering these type of belts.
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Food Industry
- English Walnuts
Walnuts are great eating but tough conveying.
Diamond Walnuts, Stockton, California is North America's largest nut processing plant
under one roof. Diamond Walnut engineers are responsible for over 20 miles of conveyor
systems that transport products from picked to packaged state.
Processing walnuts is hard on conveyor drive parts because the dusty shell fragments
are highly abrasive. There were a lot of advantages to drum motor type drives considering
the hundreds of drives it takes to power 20 miles of belt conveyors. Diamond installed
and tested two other brands before finding the right answer with Van der Graaf drives.
The other pulleys tested could not meet all the demanding requirements. Gradually
all of the existing motorized drive pulleys were replaced with the Van der Graaf
units.
Diamond Walnut Industrial Engineer, Dave Fastenau commented; "We like the self-contained,
internally driven pulleys because of compactness, safety and sanitation. We like
the Van der Graaf brand because of ease of installation. Our conveyors are designed
around their mounting style. We like the reliability and minimal downtime. We have
so many in our plant it is easy to swap them out in the unlikely event of a breakdown.
We also like the leak-free, oil seals; they allow us to operate without drip pans.
We could not do that with conventional motor, chain, gearbox drives or even with
competitive makes of motorized pulleys. We have standardized on Van der Graaf pulleys."
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Mining Industry
- Coal
Operating under the most abrasive conditions of
the coal mine the drum motor proves it's reliability.
 Mining
Technologies of Ashland, Kentucky are equipment engineers and manufacturers as well
as contract miners. They have developed a unique high wall mining technology based
on a continuous mining machine and portable 40' long belt conveyors. The operation
starts from a launch vehicle positioned in lateral fashion to the high wall. Penetration
into coal seams is at a rate
as high as 5 feet per minute. Each 40 feet in mine depth, another portable conveyor
section is added on. This sequence continues until the hole is 1,200' deep. The individual
holes may be 11.5' wide and 4' to 14' high. The low profile envelope of the Van der
Graaf drum motor allows more complete coal excavation than the space consuming, older,
shaft-mount type drives. Payback to the miners is very fast considering a new hole
may be completed every 4-5 hours. The combination of this unique mining technology
with the low profile conveyor construction allows mining with the removal of a minimum
amount of overburden and coal seams of less thickness may be profitably harvested.
Coal mine conditions are abrasive and harsh on power transmission equipment. Van
der Graaf seal design protects vital bearing surfaces from the damaging dust. An
appropriate analogy could be: the safest place is inside the eye of the hurricane.
The dependability factor is an unexpected bonus. The Van der Graaf drum motor pulleys
on this project were also required to meet MSHA specifications.
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