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Development of a new method of inspecting wire ropes in belt conveyors |
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Development of a new method of inspecting wire ropes in belt conveyors
Authors: J. Kwaśniewski, T. Machula
Belt conveyors belong to a group of transport facilities operated in a continuos mode. They are intended
for transporting fi ne-grained or loose materials and are often used in underground and open-cast
mines, in construction, storing facilities and in process lines. Depending on the belt type, the conveyors
are divided into two groups: those with a steel-rubber belt and those where the belt core is made of cloth.
Of major interest is the fi rst group, that is installations complete with belts with cured steel wires, in widespread
use in the extractive industry. Like every other man-made products, conveyor belts have a limited
service life which depends on the technology of manufacturing and the operating conditions. According
to the manufacturers, currently produced belts offer a guaranteed performance quality for 3-6 years. When
proper maintenance procedures are put in place supported by regular inspections of the belt condition,
the guaranteed service life might exceed 10 years. However, when the basic operating and maintenance
principles are not observed, the service life is likely to get shortened due to damage. The fundamental issue
in safe operation and maintenance of conveyor belts is a reliable diagnosis of their working condition.
New diagnostic problems appear when handling new type constructions, such as those complete
with brokers – i.e. reinforcing elements made of steel and placed above the ropes in the shape of a steel
Fleximat net or as small diameter wires.
As conveyor installations must be dependable and wholly reliable, conveyor belts have to be inspected
frequently and regularly, to avoid major breakdowns and failures due to belt breaking, which brings about
considerable fi nancial losses to the company as the installation has to be shut down whilst the conveyor
belt is being replaced or repaired.
Magnetic inspection is a state-of-the art method of assessing the rope condition whilst in normal
service, moreover the results prove to be adequate and reliable. Magnetic inspection tests are performed
by specialists from the Department of Ropeway Transport of the Faculty of Mechanical Engineering and
Robotics of AGH-UST in Kraków.
Magnetic inspections of conveyor belts with steel ropes have been performed for more than ten
years, yet the problems involved in quantitative evaluation of their safety features have not been fully
solved yet.
In order to assure an unambiguous and precise interpretation of the magnetic inspection data, the
idea was put forward to model all potential rope defects, those occurring at the stage of design and during
their service life.
However, as signal waveforms from a number of modelled defects were vastly similar, the metrological
properties of the measuring apparatus had to be modifi ed accordingly.
This mathematical model underlies the design of a prototype magnetic circuit in a measuring probe
to be applied in magnetic inspection of conveyor belts reinforced by steel nets.
In the new probe design, governed by the mathematical model, metrological properties of the probe
are modifi ed and the obtained signal allows for locating the points where brokers are present
Keywords: diagnostics, magnetic testing |
2011