World’s longest plastic energy chain setting new performance records

Running continuously for 24/7 or standing idle for months
on end – these are the extreme conditions that the world’s longest plastic
energy chain has to cope with at the lignite-fired power station in Tušimice,
Czech Republic. The roller energy chain system from igus has been achieving
this for ten years now without missing a beat on the record travel length of
615 metres.

In normal operation, lignite (brown coal) is extracted
from the opencast mine and conveyed directly into the lignite-fired power
station. However, if coal production is interrupted for any reason, it goes
without saying that supplies must continue to go on generating energy. The
operators of the power station, the ČEZ Group, do this by stockpiling large
quantities of coal nearby. At Tušimice the coal is stored in a long heap on the
periphery of the power plant site, which theoretically could be used to fuel
the power station for a full week. To pile the coal automatically on the heap,
a ‘stacker’ is used. To supply the stacker with energy, data and media, the ČEZ
Group opted for an energy chain system from igus. Result: 615m travel – a world
record.

10
years of reliable operation in award-winning application

The application in Tušimice was awarded the Golden
Vector Award back in 2010. Every two years, igus initiates this competition to
select the toughest and most exciting energy chain applications. Ten years
later, this system is still working extremely hard, with plenty of life still
left in it.

The project was managed by Hennlich, a stocking
distributor for igus based in the Czech Republic. At the Tušimice power station
the 5050RHD energy chain is used. The ‘R’ in the name stands for ‘rollers’.

“By using a roller, the coefficient of friction
on long travels drops dramatically, when the upper run of the chain runs on the
lower run,” explains Frank Schlšgel, Head of Engineering Projects, Sales
& Marketing at igus. “Because of the lower friction, up to 57 percent
of the required drive energy can be saved. Which, of course, is all the more
worthwhile on record-breaking travels like this one.”

With his project engineering team, Frank Schlšgel
supervises special projects around the globe and accompanies customers closely
in every step. From the first design and detailed planning stages up to
assembly and even maintenance.

Problems
are a thing of the past

Before the igus energy chain system was installed at
Tušimice, a cable drum was used. During the cold Czech winter, the cables froze
up time and again which could result in failures and unplanned shutdowns.

These problems have been a thing of the past for ten
last years. Working with Hennlich, igus developed a complete package for the
application. Since then, only regular visual inspections have been carried out.
The overall balance: Over the entire period, just ten crossbars have been
replaced. A job done in a few seconds. Not counting the inspection walk along
the 615m travel.

Along with the 615-metre record travel, two more
systems are being moved with roller energy chains from igus – one is a
400-metre travel, the other is 150 metres. The two systems supply the
‘reclaimer’, which removes the coal from the pile and transfers it to the
conveyor belt that runs to the power plant.

Reliable
routing and safe overall concept

Inside the energy chains are various chainflex cables
from igus, which have been developed specifically for use in energy chains. In
addition to the chainflex motor and control cables, a fibre optic cable is used
for data transmission.

“Bus cables are out of the question for these
long travels, as the signal strength would be insufficient,” says Frank
Schlšgel. A water hose is also routed in the chain together with a heating
cable that prevents the water from freezing inside the hose. The water hose is
needed for the sprayer at the end of the stacker. When the coal is mined and
piled up onto the heap, there is a lot of dust. This is counteracted by
continuous spraying.

Since commissioning, electronic monitoring has been
carried out on the energy chain systems in Tušimice. This measures the
push/pull forces of the chains and can switch off the system if the forces
become too high. This can happen when debris enters the system, for example. In
recent years, igus has further developed this form of ‘condition monitoring’,
or isense as it is known and today offers machine builders modules for
monitoring and predictive maintenance as an additional safeguard. Under the
‘smart plastics’ range, this includes break (isenseEC.B) and push/pull (isenseEC.P)
monitoring modules. In the event of a chain break, the system can be switched
off, so that further damage is avoided. To complement this, the abrasion
monitoring module (isenseEC.W), measures the wear of the energy chain
continuously to provide a reliable indication of the remaining service life of
the system. This enables a planned replacement of the system without sudden
failures.

Continuous
operation as proof of quality

Admittedly, the stacker moves only at a moderate speed
with about 20 minutes needed to cover the 600 metres. Every now and then the
system is not used for a whole month. But when the time comes and the coal
needs to be conveyed to the heap or is needed from there, the operator can
trust that the system will work reliably with the igus energy chains regardless
of the season. Even in these harsh conditions and after more than ten years.

Available
from Treotham

Treotham Automation is able to supply and service all
applications that require the record breaking energy chain and cable from igus.
For more information, please visit the Treotham website www.treotham.com.au or call 1300 65 75
64.

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