Stacker, Shiploader, Hopper, Bucket Wheel Reclaimer Manufacturer
While each conveyor idler is aligned during installation, external impacts, excessive carry-back, or hurried bearing replacements can throw it out of alignment, which can be quite costly.
During inspections or repairs of conveyor idlers, you may observe that the roller surfaces have become polished. This occurs when there is slippage between the belt and the roller, indicating misalignment of the rollers.
Even a slight misalignment can increase the load on the belt and result in higher power consumption at the drive motor. It can also cause belt mistracking and accelerated wear, leading to material spillage or other issues. While each conveyor idler is aligned during installation, external impacts, excessive carry-back, or hurried bearing replacements can throw it out of alignment, which can be quite costly.
Before delving into alignment details, let's review the basics of conveyor idlers. The role of the idler is to support the belt and bear the load on the carrying side. In the case of troughed belts, the carrying idlers also shape the belt.
On the return side, the belt is flat and unloaded, so return idlers do not experience the same loads as those on the carrying side. For troughed conveyor belts, idlers typically come in sets of three rollers. The central horizontal roller bears most of the load, while the side rollers lift the belt to form the trough, enhancing carrying capacity. The angle of the side rollers depends on the material being conveyed, often set at 35° but varying based on specific needs.
To ensure proper tracking, some idler sets may include additional guide rollers. These rollers ride on the edges of the belt, preventing lateral movement.
To prevent slippage, the axis of the rollers must be perpendicular to the belt center-line. Misalignment can occur in any of the three axes, referred to as:
This occurs when one side of the idler set is higher than the other, potentially causing the belt to shift sideways and leading to material spills. Guide rollers on the higher side may experience increased wear, although slip between the belt and roller is minimal.
In lateral misalignment, the center of the conveyor idler is offset from the belt's center, potentially causing uneven belt height and accelerated edge wear. Persistent lateral misalignment across multiple idlers can lead to tracking issues.
This is the most costly misalignment, as it increases the load on the drive motor. It occurs when the idler axis deviates from 90° to the belt motion direction, causing slippage and resulting in a polished appearance on the roller surface.
All forms of misalignment can lead to tracking problems and increased belt wear. Vertical and lateral misalignment require significant misalignment across multiple idlers to cause significant issues. However, even minor angular misalignment can significantly increase energy consumption, especially in long conveyor systems with numerous idlers.
Misalignment can result from structural impacts, removal of idler sets for maintenance without proper re-installation, or excess carry-back on the belt, which can damage or displace return idlers.
