Maintaining the right tension is critical for conveyor belt performance and lifespan. High percentage of issues in today's production facilities actually stem from an improper level of tension between the belt and roller - Belts that are too loose will slip and track improperly. While over-tight belts can cause damage to the belt and/or other components on the conveyor, then result in unneccessary downtime and repairs.
This article shall guide you to check and adjust for the optimal belt tension for your conveyor.
The principle is find the right balance that keep your conveyor system functioning at its best, without any belt slippage. Insufficient tension can make it challenging to keep the belt on track, while excessive tension can lead to stress on the conveyance system, such as the pulleys and idlers.
In most cases, it is recommended to adjust the belt tension to the lowest possible that not causing slippage, so as to minimize any unneccessary wear-and-tear.
Determining the correct level of belt tension can be challenging, as it varies depending on the width of the conveyor. For instance, a 15cm belt may need 5.5kg/cm., whereas a wider 60cm belt may require 11kg/cm. Therefore, maintenance teams should exercise caution while adhering closely to the manufacturer's guidelines when adjusting the conveyor belt tension.
To determine if your conveyor belt is not properly tensioned, observe it for any irregularities. Incorrect tension or tracking can cause:
squealing or grinding noises
curled or cupped edges
belt residue beneath the machine.
If any of these issues are observed, check the belt tension and adjust it promptly to avoid further problems and damages.
Methods for tension adjustment vary for different type of conveyor. Common adjustment methods include:
Jack-screw tensioning is the most common method. You can find jack-screws on each end of a roller, by turning the screw you can push the bearing block toward the end and add tension to the belt.
Although simple engough, jack-screw tensioning has some drawbacks, such as a higher risk of overtensioning and a longer maintenance period. Sometimes it can be challenging to access and adjust the jack-screw as well. As the belt stetches along time, it requires regular adjustments for belt tensioning and tracking.
With tip-up tail, the end roller of the conveyor is placed on on a pivot device that elevates the roller above the frame. As the tail can only be set to one position, adjustment is required over time.
For heavy-duty conveyor systems, conveyor belt manufacturer KCB recommends pneumatic or spring tensioning devices. This method uses additional rollers on the underside of the belt connected to a pneumatic cylinder or spring-loaded mechanism.
Benefits of Pneumatic/Spring Tensioning include:
Provides consistent, parallel tensioning as the cylinder/springs automatically adapt to belt stretch over time.
Ideal for longer, heavy-duty conveyors carrying substantial loads.
Eliminates need for frequent manual tension adjustments required with basic take-up methods.
Equally moves the lower tension roller ends for even distribution of tension forces across belt width.
Reduces belt tracking issues and potential damage from improper tensioning.
For optimal performance and longevity of large-scale conveying systems, pneumatic/spring tensioning is the preferred belt tensioning technique.
The rack and pinion is a compact, easy-access conveyor belt tensioning technique. This method involves installing a rack and pinion device on the conveyor frame side, enabling operators to hand-tighten belts without affecting tracking.
Benefits of Rack and Pinion Tensioning:
Allows precise manual tensioning via the pinion gear.
Minimal risk of over-tensioning compared to basic take-up methods.
Rack notches serve as tensioning guides - aligning to the first notch indicates ideal tension.
Simple, low-profile design fits compact conveyor frames.
Requires periodic re-tensioning to accommodate belt stretch over time.
Alignment to the second rack notch signals need for imminent belt replacement.
With easy installation and tensioning access, rack and pinion devices provide reliable belt tensioning for light to medium-duty conveyor systems.
Refer to A Quick Guide To Measure And Calculate Conveyor Belt Length for belt length mearment and calculation.
Operators should be trained on how to inspect and adjust belt tension using the proper methods for that specific conveyor. This helps prevent improper tensioning that could lead to issues.
Operators should understand proper tension levels and limits to avoid over-tensioning.
Refresher training may be needed as equipment gets updated.
Belt tension should be precisely set before initial operation using the conveyor's recommended method.
After 24 hours, recheck tension because the belt will "set in" and initial tension is often reduced.
Check and adjust tracking at the same time. Tracking can be thrown off if tension is way off.
Temperature, load levels, and humidity can affect belt properties and behavior over time. Tension may need periodic adjustment to compensate.
In hot environments, belt elongation can occur rapidly. More frequent tension checks may be advised.
Absorption of moisture in humid environments can increase belt length.
Take-up devices should be inspected for wear and properly lubricated/maintained as per manufacturer recommendations.
Failure of take-ups can lead to rapid de-tensioning and equipment damage.
Copyright © 2023 KUNMING CONVEYOR BELT CO., LTD. - www.kmbelt.com.cn All Rights Reserved.