Conveyor Spillage at Metal Recovery Plant

Per your post, the conveyor problems do vary with the actual load on it.

If all rolling elements are fine and supposed to be working, and no evident misalignment is present, have you checked/examined all the conveyor structure to see if it's not bending in certain places when the load is passing over it? Just a thought.

If the belt is moving to one side or the other with a load on it then the conveyor is not level side to side. The belt will want to travel to the side of least resistance with or with out material on the belt. Friction between the bottom of the belt and its bed would mean that it will travel to the down hill side of the bed. In that it is where it is being fed and if the material is being dropped on the belt. Years of use may have cause the support to shift on one side. Check the level side to side at all supports also the straightness of the incline.

If the belt is bowed with no load on it one of three things or both. The lace is not been installed perpendicular to the length of the belt leaving one side longer then the other or the take up section is miss adjusted. One other thing usually with new belt if the length of the belt was not cut parallel with the weave can cause this.

As to the belt moving towards the feeder feeding it. Check the bed to see if it is cupped to each side. where the material is being fed on to the bed.

Many times people try to adjust the tracking by adjusting the wrong pulleys. Check for proper alignment of the head end, tail end and bend pulleys. If it has a screw take-up make sure it's equal on both screws. Adjust your tracking using the load and return rollers. If tracking is not possible, your belt is either stretched on one side, or as stated above, not cut and laced properly. Possible damage to the framework may be attributing to the problem. Check that automatic tracking is free and working properly. It should be 90 degrees to the belt. If it is not it will never work correctly.

Dear Light,

An elementary observation: if the belt had a flaw or more than one, the observer would see the repeat pattern, round and round, and discern the flaw to be inherent in the belt. If the flaw is localized to the observer, then the flaw would be physical to the location. However, we see the behavior meander with load. Neither fixed to the belt, nor fixed to a location. This leads us to, a maybe, the culprit might be the loading with its substantial variances.

Sounding out, hoping for light. We practice such insinuations here among the lesser bulbs at CDI.

L. Nordell

The conveyor responds to the physics imposed on it. Your feed geometry needs to be modified to maintain a belt in its central position. It should not be too difficult to deduce from looking at the chute geometry the obvious present and future change.

The installation looks in need of proper maintenance and repair. Idlers need to be properly installed, skirts need to be installed with neutral influence. These are not evident.

Conveyor Dynamics, Inc. (CDI) practices the design of chutes on a daily basis.

Lawrence Nordell

President

Conveyor Dynamics, Inc.

www.conveyor-dynamics.com

nordell@conveyor-dynamics.com

A second comment:

The belt behavior you note of swaying without load, is due to inappropriate alignment of the idlers/structural support of the idlers. It is evident from your photo of the idlers, that they are in need of re-alignment. If the idlers are canted, or aligned off their theorectical ideal position, in 3 of the 6 degrees of orientation, then the belt and material on the belt will cause the central position of the belt to follow the new physics.

It appears most of your equipment is fairly old. It may be beneficial to speak with a belt manufacturer. U-shaped idler pulleys tend to outperform the type you have shown. After years of working in coal mines adn having every "belt foreman" adjust the belts the way he wanted, I couldn't figure out why my belts would work good for a few days and then spill everywhere. Mandate that only one person makes adjustments, and then watch the effect for a few days. The earlier comments concerning idler pullys are where I would start. Are you sure the tailpiece was installed correctly?

First of all..a lot of thanks for providing suggestions. Then yes, the tail piece was once installed and then no alignment checking was done there. Can you suggest a simple method to do alignment checking and necessary corrections for that?