Avoid conveyor belt misalignment in 10 simple steps

When conveyor belts run crooked, there is a great risk of the rubber catching on the frame and starting to cut the steel profiles. Then it becomes both costly and dangerous. The wear and tear costs to repair and potential downtime awaits.

Conveyor belts should run smoothly, if not, something is wrong.

Here are the most important points to keep track of:

1. Check that the drive and turning drums are perpendicular to the conveyor frame

Start by checking the distances between the turning drum and the frame of the conveyor. It should be approximately the same on both sides of the tape. The same applies to the drive drum.

The distance between the drive drum and frame must be the same on both sides. — The distance between the drum and the frame should be the same on both sides. Applies to both reversible drum and drive drum.

2. Incorrect use of tensioning station on conveyor

On the tightening stations, there is a tightening screw on each side. Many people think that these screws should be adjusted when the tape goes crooked. Unfortunately, that’s wrong.

These screws have only one job; to tighten the tape itself. There are completely different parts that need to be adjusted when the tape goes crooked.

Read on to see which ones.

The tensioning screw on the side of the tensioning station should only be used to tighten the strap - not to adjust for skew. — The tensioning screw on the side of the tensioning station should only be used to tighten the strap – not to adjust for skew.

3. Misaligned return rollers

Under the tape, every three meters there is a roller on which the tape rests. The brackets in which the return roller is located have the possibility of 10-15 mm adjustment.

If the return rollers are crooked, the belt will be pulled crooked. This is mainly where the adjustment is made and is most effective. Adjust one or two return rollers and wait until the belt has made at least 3 revolutions before making further adjustments.

Adjustment of return roller under conveyor belt. — Remember to adjust in relation to the direction of travel on the conveyor belt. The speed direction is opposite on the bottom side than on the top side.

It can be challenging to see which way the roller should be adjusted. Start from the direction of travel on the belt and think of the roller as if it were a bicycle handlebar. If the tape turns to the left, turn the roller over to the right.

Or, imagine you’re sitting on the luggage rack of the woman in the Brelett commercial. Hum a little (now you’ve got it stuck in your head for the rest of the day), daydream a little, and adjust as she would have swerved out of the ditch on the highway.

4. Adjusting the stand for the support roller

If you have made the tape run straight on the return rollers, the tape will usually follow and run straight on the top side.

If there are still distortions, the racks in which the support rollers are mounted must be adjusted. The racks should be perpendicular to the conveyor frame initially.

If the conveyor’s framework is not fully bent, it can be dangerous to use an angle to align the stand. It will then be an advantage to measure the same distance from the end of the conveyor’s framework on both sides.

Adjusting rollers

Turn like with bicycle handlebars

On all rollers you adjust, it is important to adjust in the direction of travel of the conveyor belt. If you swing the stand and roll to the left, the tape will move to the left.

Watch from 1:14 in the movie to see an illustration with bicycle handlebars.

NB: Please note that the impact on the adjustment of the support roller stand is much less than the impact of the adjustment on the return rollers on the underside of the belt.

5. Sticky rollers

If Thor has been banging his hammer and the rain showers have rolled in across the country, the material can become sticky. In humid periods, a layer of several centimeters of fine material can therefore build up on the rolls.

Regular cleaning of the return rollers is important during periods of precipitation. Especially when using rollers without rubber rings.

The build-up of fine fabric on the return roller and turning drum is most sensitive to distortion. Then the tape will be pushed over to one side and you have it running.

Check that the rollers and drums are clean regularly – especially during periods of heavy rain and snow.

6. Assess the guide plate / guide rollers

It may be a good idea to mount the guide plate / guide rollers on some of the return rollers. This prevents the tape from slipping off the roll.

The guide plate keeps the conveyor belt straight. — Mounting a guide plate on some of the return rollers can prevent the belt from slipping out.

Some may only have a guide plate on the last two return rollers before the drive drum to ensure that the belt goes straight onto the drive drum. It’s a small investment that can prevent a lot of headaches. One option is to mount guide rollers on the conveyor belt.

Guide roller with ring for conveyor belt.

7. Correct loading

Sometimes the conveyor belt runs straight when it’s empty, yet it pulls crookedly when loaded. In 90 percent of cases, the cause is the point where the mass is loaded onto the belt.

The material must be fed on as centered as possible. Uneven weight distribution quickly leads to the weight of the mass pulling the belt to one side. Make sure the load is loaded in the middle of the conveyor belt.

Transshipment point where mass is transferred from one carrier to another. — This is a transshipment point where mass is transferred from one carrier to another. In the same way that mass is centered when it falls off, it should hit the center of the next conveyor belt.

8. Kilted stones

Skew can also be caused by a stone that has wedged. This happens especially in the roughing plant where there are very coarse materials running on the belts.

If a stone rolls over the side of the belt and wedges itself between the frame and the rubber belt, the belt will become skewed and at the same time create great friction that can cause the motor protection to fail.

9. Use belt tracker

When we deliver new conveyors, we usually install a belt tracker where possible. It is a device that automatically centers the conveyor belt. It has a guide roller on each side. If the tape comes into contact with a guide roller on the side, it changes the angle of the return roller and guides the tape straight.

NB: Remember to lock the tracker in the neutral position before adjusting the band for skew. Release it after you have made the tape run straight after any necessary adjustments.

Belt tracker mounted under conveyor belt — The belt tracker is mounted under the conveyor belt and pivots on a swivel. When the conveyor belt goes too far over on one side, the tracker straightens it back into place.

On older conveyors, where the drums are starting to wear out, you often find that the belt is shaking in the rain. The drums should then be replaced, but a belt tracker can be helpful in such cases.

The belt tracker is an affordable and good investment to avoid damage to the belt and conveyor frame, as well as prevent spillage if the belt goes very crooked.

10. Fixed maintenance routine

There are many parameters that come into play on the conveyor belt. When things go wrong, it’s good to know which end to start at. Therefore, checking the conveyor belt should be part of a regular maintenance routine.

It’s the most affordable and secure solution.

We’ve seen that conveyor belts that run crooked are a common occurrence. That’s why we’ve made it a key point in a separate maintenance course on carriers.

Read more about the course here: Conveyor: extend the lifespan .