What A Conveyor Belt Is
A conveyor belt
is the moving surface that carries material from one point in a process to
another. The belt is a continuous loop stretched between two pulleys. A motor
turns the drive pulley, friction or a chain drive pulls the loop around, and
whatever sits on top rides along at a controlled speed.
That is the whole mechanism. A loop that size will wander and go slack on its own, so conveyor pulleys, idlers, and take-ups hold it in line and under tension for the length of the run. Belt
conveyors are also only one branch of the family, since mechanical and
pneumatic conveyors solve the same problem in different ways, one with a
surface and one with moving air.
There are so many types of conveyor belts because the loop has to survive
whatever you put on it. A belt carrying shredded electronics solves a different problem than a belt carrying loose corrugated, and that difference
drives nearly every other design decision.
Why The Material Decides The Belt
Conveyor belt
types get sorted in catalogs by construction, but on a recycling floor the
decision runs the other way. Four material properties set the belt spec before anything else.
•
Weight and impact. Heavy material dropping from a
hopper needs a surface that will not tear open.
•
Abrasiveness. Sharp edges and grit wear a cover down
from the top surface inward.
•
Moisture and residue. Wet or greasy streams need a
surface that can be cleaned and will not rot or glaze over.
•
Particle size. Fines sift through gaps that larger
material rides straight over.
Get this wrong, and the problem shows up as a line item for belt replacement rather than as a
complaint about the design.
Hinged Steel Belt Conveyors
This is the
workhorse of recycling and waste handling. Rather than a continuous rubber
loop, the carrying surface is a run of steel pans linked together and pulled by
chains along both sides. Piano hinge construction interlocks the pans across
their full width. Pitch hinge construction joins them at set intervals.
Steel absorbs
impact that would slice a rubber belt open, which is why these units sit
beneath balers and shredders and anywhere material free-falls out of a hopper.
They handle scrap metal, glass, construction debris, and mixed loads full of
sharp edges. Crigler stocks hinged
steel belt conveyors from Hustler Conveyor Company and Endura-Veyor in both
piano hinge and pitch hinge builds. These are also what people mean by a slat
conveyor in this industry.
The trade-offs
are weight, noise, and fines. Steel belts are heavier and louder, and small
particles drop between the pans. They also require different upkeep than a fabric belt, since steel belt conveyor maintenance depends on chain tension and catenary sag rather than belt tracking.
Fabric Belt Conveyors
A fabric belt
is built from layers of woven textile bonded together and finished with a
rubber or PVC cover. The layers, called plies, carry tension and determine the belt's strength rating. The cover determines how the surface behaves.
Fabric belts
run lighter and quieter than steel, cost less to replace, and hold the fine
material that steel pans let through. They suit picking and sort lines and OCC
screens, paper and corrugated streams, and any station where staff sort by
hand. What they will not tolerate is repeated heavy impact from sharp loads.
Rubber Belt Conveyors
Rubber belt is
often used loosely to describe a fabric belt with a rubber cover, which is the
usual construction. The distinction actually worth drawing is the cover
compound. Standard rubber handles general abrasion. Oil-resistant compounds
hold up under greasy material. Heat-resistant compounds exist for hot material
that would blister a standard cover.
For most
recycling work, the compound matters more than the name on the belt.
Cleated And Incline Belts
Material that
has to climb needs help staying put. On a steep incline, a plain belt lets
material slide back down the slope. Cleats are raised ribs bonded across the
belt at intervals that hold material in place on the way up.
Almost every
recycling conveyor ends up on an incline at some point, because material nearly
always has to rise into a baler hopper or a shredder infeed. Crigler's conveyor
inventory includes incline sections running past twenty feet, paired with lower
horizontal feed sections.
Belt Types You Will See Outside Recycling
Searching types
of conveyor belts surfaces several designs built for other industries, and it
helps to know which results apply to a recycling facility and which do not.
•
Modular plastic belts are interlocking plastic
segments, common in food processing because they survive being power-washed.
•
Sanitary and washdown belts use cover materials that
meet food-contact standards.
•
Roller bed belts ride on rollers instead of a solid
deck, which cuts drag on long warehouse runs of boxed goods.
•
Curved belts follow a radius so a product line can turn
a corner.
None of these
are standard recycling machines. They show up high in search results because
warehousing and food processing buy far more of them.
Signs You Specified The Wrong Belt
Belt problems
tend to announce themselves in the same few ways, and the pattern usually points to the specification rather than the crew running the line.
•
Cuts, gouges, and punctures in a fabric or rubber cover
mean the material is heavier or sharper than the belt was rated for, or it is
dropping from too high.
•
Material sliding backward on the climb means the
incline angle is too steep for a plain belt and the run wants cleats.
•
Fines collecting under the conveyor means a steel pan
belt is carrying material finer than the hinge gaps.
•
A cover that has gone hard, glazed, or cracked points
at heat or oil attacking a compound that was not chosen for it.
•
Belt replacement intervals that keep shortening usually
mean throughput or material mix changed after the conveyor was installed.
Any of those is
worth raising during conveyor repair and
maintenance rather than treating as normal wear, because replacing the same
wrong belt on a schedule costs more over a few years than changing the
specification once.
Matching The Belt To The Machine It Feeds
The belt is one
decision inside a larger one, and what sits at either end of the conveyor
usually constrains it more than the material does.
A baler infeed wants metered,
even flow rather than surges, which points toward a steel belt with a metering
section. A shredder infeed
sees the roughest material in the building and takes it as a drop. A sort line
wants a belt set at picking height, running slowly, and wide enough for two
people to work across.
Belt width,
speed, incline angle, transfer height, and discharge point all fall out of
those constraints, along with the conveyor
guarding requirements that come with each configuration. That is why belt
selection belongs in conveyor system design and installation, not off a catalog page.
Choosing The Right Conveyor Belt With Crigler Enterprises
If you are
replacing a belt more often than expected, or adding a conveyor to feed a new machine, the belt type is worth settling before ordering anything.
Crigler Enterprises has designed, installed, and serviced conveyor
systems for recycling and waste operations since 1972, and we carry the largest
service fleet in the Southeast to keep them running.
We are a
licensed and bonded authorized distributor serving Georgia, Florida, and
Alabama, handling system design, installation, repair, maintenance,
refurbishment, and PLC upgrades.
Call
us today or reach us online, and tell us what material you are moving and where it
has to go, and we will tell you which belt belongs under it.
