INDUSTRY INTELLIGENCE
that are generated during the combustion
of fuels.
It is a concern that this additional cost
will increase the already high price of
moving goods throughout the country.
Bear in mind that South Africa’s logistics
costs have increased as a percentage
of transportable gross-domestic product
– earned in the primary and secondary
sectors of the economy – since 2010 and
are already higher than the global average.
The largest contributor is the high price
of mainly imported oil, which is an input
that cannot be controlled by government
and the road-freight industry.
The use of environmentally-classified
commercial vehicles, such as Euro 3, 4 and
5 truck engine technologies; deployment
of optimised route planning; as well as
the continued measurement of carbon
emissions; have all played an important role
in conserving this finite resource.
However, a more holistic approach
that involves all stakeholders, including
the public sector, is required to further
reduce the carbon footprint of road
transport to establish a truly ‘green’ and
environmentally-sustainable local freight
logistics system.
One of the biggest challenges that
requires immediate attention is the
deteriorating condition of many of
the country’s provincial and local road
networks, which leads to unnecessary
stopping and starting of trucks, as well as
the premature replacement of parts and
componentry.
This has been exacerbated by highly
congested corridors due to delays in
investment into large ‘brownfield’ and
‘greenfield’ road-infrastructure projects
to improve the country’s logistics
performance.
Long distances between nodes have
also contributed towards high logistics
costs and the release of large quantities
of carbon and particulate matter into the
environment.
This is a legacy of the past that used
distances to separate communities and
can only be addressed by investment
into improved spatial planning and
infrastructure that supports the
development of ‘smarter’ cities.
Due attention must also be given to
developing a truly multi-modal freight
transport system as part of this plan. It is also
essential that the barriers to the deployment
of the latest international truck engine
technology in the country be removed.
This requires a sizeable investment
by both government and the private
sector into the entire diesel fuel value
chain, spanning local refineries through
to infrastructure and fuelling networks.
Cargo Carriers will continue to invest
in environmentally responsible ways of
moving product for leading industrial
operators throughout southern Africa
and play its part in reducing GHGs to
help create a cleaner and sustainable
environment.
Preventing downtime in asphalt mixers
A variety of complex factors are involved in
the production of hot asphalt mixes, which
makes the process vulnerable to sudden
equipment stops. The consequences
of such unplanned maintenances to
the business are dire, since the cost of
having a stopped plant is high. In order
to minimise production disruptions, new
technologies applied to wear components
and electronic monitoring of asphalt
plant motors during production bring
predictability to maintenance, replacing
corrective maintenance with preventive and
predictive maintenance.
Preventive maintenance is a widespread
concept applied to equipment that has the
goal of scheduling machine stops according
to the expected amount of wear, based on
average statistics of generic applications.
Predictive maintenance on the other
hand is much more complex because it
considers the current conditions and the
dynamics of the components, according to
a specific application, in order to schedule
maintenance at the correct time.
According to Marcelo Zubaran,
application engineer and product specialist
at CIBER Equipamentos Rodoviários,
“Obtaining the correct information at the
right moment regarding a component wear
or a tendency of failure of a motor is a major
www.equipmentandhire.co.za
advantage to asphalt mix production.”
Predictive maintenance can only be
implemented with devices continuously
monitoring the equipment components, be
it mechanical or electronic devices.
Components with an abrasive wear
profile developed over the lifetime of the
tool could use a predictive maintenance
plan. The plant’s mixer vanes exhibit wear
proportional to the time used and thus,
through physical markings on the vanes, it
is possible to have a visual response on the
wear level and predict when to replace the
component.
The conditions of the plant’s bag filters
are monitored indirectly during production
through pressure meters installed in the
filter box, which indicates if the filters are
likely to saturate. This prevents further
damage to the filter elements and even
wear of the plant hood.
On the other hand, state-of-the-art
technologies such as constant monitoring
of the power consumption of motors during
production, known as the fault diagnosis
system, also provide valuable information
to the operator in real time on the operating
conditions of the motors. “If any of the
plant’s motors are not operating at its
optimum condition, the plant immediately
triggers an alarm. The operator may choose
to conclude a particular asphalt mix demand
and then check the conditions of such motor
or stop the plant. In this way, predictive
maintenance technology allows us to
perform preventive maintenance,” says
Zubaran.
To enable this technology, it is
necessary for the motors to be connected
to an electrical current measuring device
and for such a device to be connected
to some data transmission network.
Frequency inverters coupled to motors,
which allow varying their rotational speed,
can measure the current of a motor. In
addition, technologies such as Soft Starter,
which smooths the start of ‘big’ motors
without frequency inverters can measure
the electric current, and integral starter
systems, like Tesys U, can also measure
the current of motors. Such devices
must have a network interface in order
to enable digital communication with the
plant’s computer, which will manage this
information through a software.
These technologies tend to minimise
unplanned stops and enable assertive
maintenance planning. Consequently,
productivity is increased, production and
logistics costs are reduced, which is the
only possible way of achieving just-in-time
logistics.
OCTOBER 2019
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