Belt Tensioning
One of the main mechanical tools used to move
items around the Warehouse or Fulfillment Centers is Conveyors. They are also
used in mail and packaging centers, airports, rock and earth material yards,
construction and even in grocery stores. There are many challenges in making
sure the conveyors run smoothly and with minimal downtime. One of the main
issues with conveyor belts is proper tension. With a confident understanding of
how the belt will react under-tension, you can maximize the life of the equipment.
Once a conveyor belt has been tensioned
properly, tracking the belt will be easy (and we will cover that topic later).
Not having the right amount of tension could cause the belt to slip and the
product would stall. If this happens, the main drive roller would continue to
spin and heat up, causing a large amount of friction and could melt to the
belt. If there is too much tension on the belt, the lacing could tear apart, (we
will cover belt lacing later too). The other issues with over tension are the stress
added to the end rollers, bearings and drive. The motor will have to work
harder as well, causing it to overheat.
With the proper technique of tensioning, the
life of all moving mechanical components will last to their expected cycle, if
not longer. I will list the steps that are needed to make the proper
adjustments and tension you will need to make. It is important to make sure
that the driving pulley can drive the belt without slipping even under maximum
load.
What
is Proper Tension?
Proper belt
tension is the lowest tension that will not cause the belt to slip and is
required for the conveyor to run smoothly. Without the correct tension, the
belt can cause unnecessary wear to the conveyor parts. Either too much or too
little tension can damage the conveyor.
Too much tension. A conveyor belt with too much tension
can lead to excessive wear on parts such as bearings and shafts. The extra
pressure can also cause the pulleys to break and wear down prematurely.
Tracking problems can also arise leading to uneven belt wear and, if not
addressed, many additional issues with the conveyor.
Too little tension. A belt with not enough tension can cause
the belt to slip. The loss of belt tension will cause wear to pulley lagging,
improper belt tracking, and premature belt failure.
It is important that the belt have been
sufficiently tensioned in order to guarantee a slippage-free operation after
the relaxation phase. Therefore, the
correct tensioning procedure and the observation of minimal initial elongation
are important. This will extend the life of the belt, lacing, bearings,
rollers, and the motor/reducer. Remember, in most warehouses and fulfillment
centers, the packages are not very heavy. The average weight of a package from
the company that I work for is less than five pounds.
Recommended
initial elongation:
Procedure for First-time Tensioning
1. Place two measuring marks on a distance
of 1000 mm on each side of the untensioned belt. This can be done with a paint
pen, marker or tape.
2. Tension the belt with the tensioning
device to the required initial elongation. Once the two marks have reached 3
mm, you have successfully added the right amount of tension. If you do not have
to space for 1,000 mm, cut all of the measurements in half; i.e., 500 mm mark
distance and stretch to 501.5 mm by adding the only 1.5 mm.
At for example 0.3% initial elongation, the
correct tension is achieved, if the distance of the marks has increased to 1003
mm. Rotate the belt at least one circuit and measure the distance between the
marks again. Retention the belt to the required initial elongation when
necessary.
Special care has to be taken when a conveyor
belt needs to be untensioned (and possibly removed in order to perform
maintenance work) and finally installed and tensioned again. This is where you
need to make marks on the sides of the tensioners so you can place the belt
back in its correct position.
Note: Retensioning of a released conveyor
belt with the described method for first-time tensioning results in over
tensioning, as the new elongation will be added to the not yet fully released
initial elongation.
Before slackening the belt, place measuring
marks on a distance of, for example, 1000 mm on each side of the tensioned
belt. If the marks of the first tensioning are still visible, these can be used
as well. Memorize or Take a note of the original distance between the measuring
marks of the tensioned belt.
Slacken the
belt by releasing the tensioning device. The distance of the measuring marks
gets shorter; however, the released length (x) is not of interest.
After the
maintenance work is finished, reinstall the belt and tension it until the
measuring marks reach the previously noted distance (for example 1000 mm).
As you read
this week’s blog, you now have a better understanding of “Belt Tensioning”.
When the transport belts are tensioned properly, there will be less stress on
the rotating parts, in return, less repairs needed due to equipment failure.
Properly tensioning a conveyor belt is a critical step in tracking conveyor
belts. Getting the correct amount of tension reduces splice failures, excessive
stretch, and wear on the side of your frame. Luckily, there is a simple
procedure to achieve the proper tension on a belt that we have covered!
In Conclusion my friends; what are some of the
topics that we talked about here supported your needs? What are some of the
challenges in belt tensioning do you need support on?
I hope that
this blog supports your needs and delivered good content for you! Please feel
free to leave a comment and follow along with the journey!
Best Regards.
Joe DeLoach
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