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Built competitively with a few modifications in
critical areas, an evolved basic conveyor is a
standard bulk material handling conveyor designed
to allow easy retrofitting of new components that
improve operation and solve common maintenance
problems.
One key to designing an evolved basic conveyor
is knowing the most critical requirements for the
current operation and anticipating later production
needs. Nearly 90% of the time, transition idlers
in the tail zone never touch the belt, making them
a wasted expense. Since transition idler frames
can make it difficult to install and maintain tail
plows, forgoing transition idlers for tail protection
is recommended to prevent belt and pulley fouling
from fugitive material. Further, there should be
enough space between the upper and lower
run of the belt for installation of a plow by using
larger terminal pulleys with a minimum diameter of
600 mm (
≈
24 in.). In addition to a larger tail pulley,
an oversize head pulley also allows for more than
one belt cleaner in the chute, which mitigates
spillage along the belt path. Applications with tacky
carryback should consider using a scavenger
conveyor, which accommodates off-pulley cleaners
along the conveyor return after the head pulley.
Installing or providing for maintenance-minded
solutions in the loading zone can greatly improve
safety and reduce man-hours and downtime.
These components include slide-in/slide-out idlers,
impact cradles and support cradles. On larger
conveyors, maintenance aids such as overhead
monorails or jib cranes assist in the movement and
replacement of components. Also, designers should
ensure adequate access to utilities – typically
electricity and/or compressed air – to facilitate
maintenance and performance. Next-generation
conveyor designs feature a specially engineered
idler capped with an independent power generator
that uses the conveyor’s movement to generate
power for a wide array of autonomous equipment.
Dust, spillage and belt tracking are top concerns
for many safety professionals. Field tests have
shown that enlarged skirtboards and engineered
settling zones promote dust settling and reduce
fugitive material. Curved loading and discharge
chutes control the cargo transfer for centred
placement and reduced turbulence. As the load
is centred on the belt, guides ensure even travel
through the takeup to promote consistent belt
tracking.
Any transfer point is prone to buildup and
clogging under the right conditions, be it ambient
humidity, material wetness, volume or surface
grade. Flow aids such as vibrators or air cannons
on chutes can sustain material movement,
improve equipment life and reduce the safety
hazards associated with manually clearing clogs.