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:: SILO COMPLEX
The equipment used
in the complex includes:
- Chain and flight
conveyors with accessories
- Belt and Bucket Elevators with accessories
- Destoner
- Magnet
- De-Awner
- Cleaner Grader
- Automatic sack weighers
- Hopper bottomed and Flat bottomed silos
- Detachable sweep auger
- Full range of diagnostic equipment for stored grain
- Grain ventilation/aeration system
Chain and flight
conveyors
There are 11 chain
and flight conveyors of varying lengths incorporate in this complex.
These conveyors drag grain along the floor of the conveyor and are by
design one of the least injurious to grain integrity.
Screw conveyors
are avoided in this complex even in the unloading sequence in order
to minimize grain damage. A special unloading design in the silo foundation
allows silo discharge by chain and flight conveyor.
The chain and flight
conveyors come fitted with limit switches for optional automatic grain
handling from the control panel.
A host of accessories
like mid-length slides and two or three way valves are connected to
these conveyors at specific points for maximum versatility in grain
movement and re-circulation.
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Belt and Bucket
Elevators
No less than 6 elevators
of different heights and capacities work in association with the conveyors
to achieve versatile handling. Four of these elevators are centred in
the hub building which also houses the cleaner grader, de-awner and
the destoner. The remaining two are located round about the separate
hopper bottomed silo.
The buckets (cups)
which carry the grains are attached to the elevator belt via locknuts.
The locknuts prevent loosening of the cups reducing the likelihood of
mixing of bits of equipment in the grain bulk.
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Destoner
This piece of equipment
which also functions as a density separator has a rated capacity of
12.5 tons/hr and comes with a feed bin of 10-ton capacity. The destoner
uses the principle of density to separated small similar sized stones
from the grain bulk by a combination of vibration and pressurised air
flow. The removal of these stones prolongs the life of milling equipment.
The destoner also removes dust generated from the moving grain by aspiration.
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De-Awner
With some grains,
sorghum especially, the covering of the corns (known as glumes) which
are attached to the stalk remains to a large extent even after threshing.
The de-awner breaks off this attachment which facilitates the separation
of glumes from corns. The de-awner is found on the loading sequence
before the cleaner, allowing the space in the silo to be optimally used
by excluding the unwanted glumes.
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Magnet
A permanent magnet
is attached to the slide for the loading pit to remove unwanted metal
items.
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Cleaner/Grader
The cleaner/grader
is a flexible piece of equipment allowing a combination of cleaning
options:
The first line in
the cleaning process is the aspiration of the seed. A by-pass is provided
so that grains may be discharged directly after the aspiration without
passing over the screens mounted on the rotating drum.
The second line
of cleaning is done in the rotating drum. When the product is directed
to the drums, the two-way valves fitted underneath the cleaner at its
outlets allow the screens to be utilized in two ways:
• Grading
- with small perforations allowing small seeds, broken grains and small
impurities
• Rubble separation – using large perforations allowing
clean grains to pass through the screen and over tailing large impurities
According to the
screens employed and the adjustable angle of the rotating drum and the
speed of rotation, a very high performance can be achieved.
First pass pre-cleaning
can be done to a very high output; however, the conveyors and elevators
are rated at 30 tons/hr to allow for very fine cleaning and sorting
to merchantable standard.
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Semi-automatic sack
weighers
In a building separated
from the hub, holding bins and semi-automatic sack weighers are available
complete with sack tracks, and automatic bag stitchers for smooth and
efficient running. This option is available to customers who do not
wish to take advantage of the bulk loading facility. Two bagging lines
are available giving a total bagging capacity of 18 tons per hour (360
50kg sacks per hour).
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Hopper- and Flat
bottomed silos
The complex consists
of 6 (six) 2000-ton flat bottomed silo bins and 1 (one) 300-ton hopper-bottomed
silo.
The hopper bottomed
silo is completely self-emptying and allows for even gentler treatment
of grains. At present this silo serves the malting factory and is actually
the end of the process line, where finished malt is stored in readiness
for bulk out load or bagging, depending on customer requirements.
The six flat-bottomed
silos are mounted on a raft-foundation in two lines of three with two
discharge conveyors running parallel to each other underneath both lines.
These conveyors feed back to the hub. This allows for easy re-circulation
if & when required for optimal grain-in-store management. This arrangement
is also kinder to grain reducing grain damage by avoiding the use of
screw unloading augers. Unloading slides attached to the discharge conveyors
allow the option of manual or remote control via the control panel.
The flat bottomed silos are used to store raw grains for different customers
with the option of passing the grains into the processing factory or
bagging out after destoning.
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Detachable sweep
auger
This appliance is
used in conjunction with the flat bottomed silos. At the tail end of
silo emptying, the sweep auger is attached to the central discharge
point of the silo. The sweep auger ‘sweeps’ the remaining
grains towards the centre and thus completes silo emptying with minimal
manual labour.
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Diagnostic equipment
In order to monitor
the condition of the grains while in storage, a complete range of silo
monitoring equipment forms part of the in-built grain management system.
Thermal and humidity probes monitor ‘hot-spots’ and relative
humidity levels at up to 9 sensor points per bin. These probes are patched
in to a separate electronic monitoring device which has a printer application
for keeping records of storage conditions.
High and low level
proximity sensors allow accurate determination of fill levels in each
bin.
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Ventilation/Aeration
system
There are 6 (six)
high pressure double axial fans linked into a ventilation duct network
cast into the concrete base of each bin. This is one of the control
features of the grain management system. In cases of high humidity or
‘hot-spots’ (danger of condensation and mould growth), the
fans can be turned on to ventilate/cool the grain and equalize temperature
and humidity levels between the air outside the bin and the air inside.
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