How to Track a Conveyor Belt

How to Track a Conveyor Belt

Often, the blame for conveyor belt misalignment is unjustly placed on the conveyor belts themselves. However, the root causes of these issues typically lie in the installation process. Issues such as misaligned pulleys and rollers, incorrect belt tracking techniques, or design flaws can lead to significant problems. Understanding and applying the right belt-tracking strategies is crucial to extending the conveyor belt lifespan.

In this guide, we’ll walk you through the steps to properly track your conveyor belt, keeping your operations running without a hitch. And here are steps that can help adjust a conveyor belt to run straight.

Step 1: Understand Your Conveyor Belt System

Before you dive into tracking, it’s crucial to understand your conveyor belt system. There are two main types of conveyor belts: those that run on a flat surface and those that operate on troughed rollers. The type of belt your system uses will influence how you track it.

Step 2: Inspect the Conveyor Belt

Begin with a thorough inspection of the conveyor belt itself. Look for any signs of wear or damage, such as tears or frayed edges. These issues can affect how the belt tracks and should be repaired or addressed before attempting to track the belt.

Step 3: Check the Belt Tension

Proper belt tension is critical for accurate tracking. A belt that’s too tight can cause excessive wear, while a belt that’s too loose can slip off the track. Check the manufacturer’s specifications for the correct tension settings and adjust as needed.

Step 4: Align the Rollers and Pulleys

Misaligned rollers and pulleys can lead to tracking issues. Use a straightedge or laser alignment tool to check the alignment of these components. They should be square to the direction of the belt travel and parallel to each other. Adjust any misaligned rollers or pulleys to ensure they are correctly positioned.

Step 5: Test and Adjust

After making adjustments, run the conveyor belt at a slow speed to observe its tracking. If the belt drifts to one side, you may need to make further adjustments. This can involve tweaking the tension or realigning rollers and pulleys until the belt runs centrally.

Step 6: Regular Maintenance is Key

Regular maintenance is crucial for keeping your conveyor belt running smoothly. Schedule routine inspections to check for wear and tear, ensure rollers and pulleys are aligned, and confirm that the belt tension is correct. This proactive approach can prevent minor issues from turning into major problems.

Conveyor Belt Tracking Rules To Know

It’s important to differentiate between basic and supplemental tracking methods. Basic methods are designed to keep the belt properly aligned under normal conditions, without significant external pressures like side forces. On the other hand, supplemental measures are needed when basic methods fall short or are unsuitable for ensuring the belt remains on track.

For effective belt alignment, certain conditions must be met:

  • The supporting structure must be robust and stable, capable of handling all exerted forces, such as belt tension, the weight of transported items, and uneven flooring.
  • Pulleys and rollers need to be installed perpendicular to the belt’s direction. Any adjustments to pulleys and rollers should only be made after the belt is correctly in place.
  • Components of the installation that interact with the belt should be kept clean and free from debris.

What if a Conveyor Lacks Tracking Measures?

Without proper tracking measures, a conveyor belt operating over cylindrical pulleys aligned perpendicular to its path experiences forces parallel to its direction, lacking any tracking force. This scenario leads to an unstable equilibrium for the belt, making it susceptible to deviation at the slightest interference—be it uneven loading, dirt accumulation between the belt and pulley, belt distortion, or lateral movement of goods.

Incorrect alignment of the pulleys, even slightly, exacerbates the issue, causing the belt to drift towards the side with less tension.

Here are 3 basic rules to follow while tracking conveyor belts.

1. The direction a belt leans towards is the side with less tension.

The Role of Shaped Pulleys in Conveyor Belt Alignment

Conveyor belts typically include one or more pulleys shaped in a cylindrical-conical or radially crowned manner. This design often suffices for ensuring the belt runs straight and stable.

Shaped pulleys contribute to automatic belt alignment. When the belt starts drifting or changes direction, these pulleys help recenter it without needing manual adjustments. More details on the design benefits of these pulleys are available.

In conveyors with a simple two-pulley system and a fixed running direction, the head pulley (the driving pulley) usually features a cylindrical-conical design.

For conveyors with a length-to-width ratio greater than 5 to 1 or those that operate in both directions, it’s recommended to shape both the head and tail pulleys for optimal belt alignment.

Benefits of Radially Crowned Pulleys

Using radially crowned pulleys helps keep the belt properly aligned, preventing it from drifting, provided the pulleys aren’t overly bent.

When Extra Belt Alignment Efforts are Needed

In setups prone to significant belt misalignment and where lateral forces are at play (due to side loading, diverter bars, or multiple direction changes), relying solely on shaped pulleys might not be enough. The necessity for additional alignment strategies will depend on the specific application and operational demands.

2. Enhancing Belt Tracking Through Increased Contact Arc and Friction

The effectiveness of belt tracking improves with a larger contact arc and higher friction levels. To minimize belt tension, the belt’s pivot movement should ideally be perpendicular to the central line of the contact arc. It’s also essential for the distance between the end pulley and the guide pulley to be at least double the diameter of the larger pulley.

Enhancing Belt Tracking Through Increased Contact Arc and Friction

Adjustable cylindrical rollers differ from cylindrical-conical pulleys because they lack an inherent self-tracking ability. This means that any change in the belt’s direction requires a manual adjustment of the rollers’ position, which is not feasible for reversing operations. Therefore, using adjustable cylindrical rollers for belts that move in both directions is generally not advised. However, an exception exists for longer conveyor systems where the distance between guide pulleys is sufficient, allowing their use even in systems with reversing directions.

Visualizing Belt Tracking Friction

Imagine guiding pulley A correctly aligning the belt when it moves in one direction, and guiding pulley B doing the same for the opposite direction. This illustrates how different components work together to maintain proper belt alignment across varying directions of movement.

3. Contact Sequence in Belt Tracking

The initial contact point between a belt and a series of pulleys or rollers plays a critical role in determining the direction of the belt’s tracking. For instance, in a setup where roller A is the first contact point, it has the most significant influence on the belt’s path.

Adjusting Belt Path with Inclined Rollers Placing inclined rollers on the underside of the belt, especially near the entry point before the tail pulley (for head drives) or the drive pulley (for tail drives), optimizes the tracking effect. This placement is crucial for ensuring the belt remains aligned.

The friction between the belt and rollers, especially when the rollers are positioned directly beneath the belt, helps in maintaining the belt’s direction. Yet, it’s important to consider that this might leave marks on the belt surface. Alternatively, positioning rollers above the belt can protect delicate or intricately designed surfaces.

For an effective adjustment, the roller’s contact area with the belt should cover about a quarter of the belt’s width, with an inclination of 5° to 10°. Aligning the rollers perpendicularly to the belt’s motion allows for automatic realignment if the belt starts to veer off course, applicable even in systems that operate in reverse.

Enhancing Belt Tracking

Tilting the rollers slightly forward, between 8° and 10°, at the belt’s edges can improve the tracking effect, potentially augmented with a friction cover for better grip. However, this forward angle is not suitable for conveyors that run in reverse, as it can disrupt the belt’s centering forces.

In situations involving wide, short belts or thin belts at high velocities, inclined rollers on the return side prove to be effective. To prevent issues like folding, both driving and tail pulleys should have cylindrical profiles.

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