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Today, the company has manufacturing plants
strategically located to serve high-growth markets,
with docking facilities in both countries to take
advantage of efficient water transportation. This
association allows them to achieve synergies and
economies of scale, strengthening their ability to
provide excellent service and top products to builders
of all sizes in all of their locations.
A new solution
There have been several traditional methods of
reclaiming cement from large capacity structures. The
methods vary significantly from the complete aeration
of structure floors, to partial aeration with manual
final clean out (using front end loaders), to large
mechanical reclaim systems. All of these options offer
advantages and disadvantages, which primarily involve
overall cost, level of automation and safety.
Laidig Systems worked with St Marys and other
cement companies to develop a solution that best fit
the needs of the industry. After considerable research
and development, Laidig manufactured the Fluidized
Screw Series Reclaim System as a cost-effective and
automated solution to unload fluidisable materials in
large capacity storage structures. This technology
offers enhanced performance and dependability
for a wide range of fluidisable materials, such as
cement, fly ash, talc, and other powders. The system
is engineered to provide a fully-automated, near-total
clean out while breaking up the hard pack and
avoiding the dead zones.
How it works
The Fluidized Screw Reclaim System was developed
to satisfy certain requirements of St Marys Cement,
and in doing so, was engineered and manufactured
with features that were essential for the efficient
and effective operation of their particular system.
Development began with state-of-the-art engineering
and design specific to the customer and their unique
needs. For St Marys, the system was designed to
meet their difficult material challenges and provide
some other key features:
f
A fully automated system with dependable push
button operation.
f
A fully reversible sweep auger for maximum
process flexibility.
f
The ability to support storage diameters up to
164 ft (50 m).
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Integration of an efficient air-gravity conveyor with
a rugged mechanical screw reclaimer.
f
Access to Laidig’s lifetime technical support.
The system that Laidig developed for St Marys
integrates the best of two proven technologies
to solve their material handling needs: a rugged
mechanical screw reclaimer and an efficient
air-gravity conveyor system to unload and clean out
the dome. These totally automated reclaim systems
provide the efficiency of air-gravity conveyors
along with the ruggedness of mechanical screw
reclaimers. In this process, air gravity conveyors,
which consist of an aerated centre hub and radial
spokes, reclaim a large percentage of the total
stored material. A series of air slides are used
to fluidise the floor and cleanout a portion of
the material in the dome. The air slide system is
comprised of radial air conveyors – designed like
spokes on a bicycle wheel – extending out from the
centre. The air slides operate sequentially around
the dome – i.e. not simultaneously – which reduces
the amount of power to operate them, and reduces
uneven loads on the dome and foundation. This
process will reclaim approximately 80% of the stored
material, leaving behind large pie-shaped piles of
material between each air slide.
To ensure final cleanout, the system is engaged to
unload the dome, further break down the material, and
clean out the remaining hard packed piles to complete
the clean-out process. To assist in activating the
air-gravity zones within the storage facility, an intelligent
control system sequentially activates the air-gravity
zones to coincide with the location of the reclaimer, to
aid in the completion of the final cleanout.
Safety
Safety is also a high priority for St Marys and other
companies storing materials in silos and domes;
and, one of the challenges is to ensure that plant
personnel have safe and easy access into the
structure. Laidig was proactive in their approach
to help ensure that this would not be a concern
when storing and transporting fluidisable materials.
Laidig has engineered and developed new product
innovations and pioneering technologies that have
changed how companies approach material storage
Installation of a Fluidized Screw Reclaimer at
St Marys, Charlevoix.
40
World Cement
July 2020