Conveyor Pulley Replacement on a Stacker

Wow. You gave a lot of nonuseful or not enough useful information. In this age of cell phones with cameras, pictures would be exceptionally easy and useful.

If we release the belt tension, how we can remove the belt to easily access the pulley and remove it?

I give up! How can we (without knowing your particular setup)?

Much more description of your particular setup OR pictures would be the next step on your part.

Sorry mate, definitely not much information here. See the image below, the head pulley is located right at the head of stacker, and then the conveyor goes back, connected to the twin drives on ground and then further goes back to 1.5km to the tail end where take up winch assembly is located...e

Slide a flat bar in between the belt and the frame; work the bar to the end of the head pulley; rig threaded rods to bush the bar a few inches away; etc.

I've use a toggle action with latches or fasteners.

On smaller conveyors, I just used the toggle action.

This belt is Steel cord belt, vulcanized. So are you suggesting to rip apart the splice, hold it using clamps before and after head pulley and replace the head drum??

If we release the tension, put a flat bar between the belt and frame (As tornedo suggested) and rig the bar and lift the belt, still it will be over the pulley and hindering the crane access to lift up the pulley? Is there any other way to replace the pulley without cutting the belt???

Thanks,

As mentioned, work the flat bar past the pulley, not still above it; and then push it outward. (This will require that the belt has sufficient slack when the takeup is retracted.)

Thanks Tornado, you have seen the picture of pulley on stacker so we will have to build scaffolding around the head. Then where we park the crane is another issue, plus steel cord is a heavy belt so we will have to shift the slack gradually to the head end.

The nose assembly is usually bolted on. You could loosen belt tension. Unbolt the nose section and slide the whole assembly out from the side to make the repairs.

There are thousands of conveyors around the world and they all need this sort of maintenance sooner or later. The procedure is pretty standard but you will need to break the belt at the join or, if there is no join, cut it and refasten it. You will also need some specialised belt clamps and a 'come along'. Your belt supplier will school you in the best method to use and you can make your own clamps.

It may help to find out how the belt was assembled in the first place.

You're going to drop a big wad of cash just changing the pulley. Presumably you have some engineering help with the root issue--breaking bolts in the head pulley attachment to the shaft? You probably don't want to replace the pulley twice.

That part of the problem sounds like excess shaft deflection or oilcanning of the pulley end plates.

Jon.

Yes, the reason is pretty much know, a survey was already carried out and the pulley was found overstressed. Anyway, a new upgraded pulley design is in progress and it will be available soon for fabrication but in the meanwhile, replacing this pulley is a challenge as it poses a big hazard operating in current condition.

No body is willing to cut the belt as it will take much longer to splice and we dont have a good history of QC on belt splice.

If you don't want to cut the belt then you will have to pull it forward once it is slacked off to create space around the pulley. From there, I would investigate pre-making a steel frame that could be lifted with a crane and slid under the existing pulley. It would be bolted or temporarily welded to the head end of the conveyor structure. It would serve as a "skid" to let the old pulley down on to be pulled sideways out from behind the belt, out to where you could rig it so the crane could lift it out.

The frame would be made ahead of time and disposable...just a tool to change out the pullies.

Alternatively, have you talked to belting service companies about the steel cable splicing? It is a pain to do, as the cables have to be staggered, meaning multiple belt cooks, yadda, yadda, but it may be less money and quicker than fighting with pulling the head pulley out from under the belt.

As to belt splice quality control, you need to get some trade references and check them out. I'm sure you know people in industries the same as yours who also use the same kind of belts. Talk to them about who they are using for belters. Your existing belt was spliced into place- So someone did the first splice, and it is apparently holding up!

Hope this helps,

Jon.

Thanks Jon, I will enquire further about the frame you mentioned above.

As it's a long belt with 800m on the ground and then 700m at Inclination on the stacker, once we release tension through Takeup, I dont think we will be able to pull the belt forward straightaway. The slack needs to be shifted gradually from the take-up point. Can you please confirm if this assumption is right?

No, I don't believe your assumption is correct. I just typed up a long answer to this question but got an error message when I tried to post it.

I'll try to find out what to do to repost.

Jon.

2nd try at posting this...thanks to instructions from Old Salt.

Although I don't have any experience with a belt as long as the one you describe, consider a couple of common-sense details of this belt conveyor:

1. The belt is driven with a single drive pulley (Is this assumption correct?)

2. The belt is carrying product that is significantly heavier than the belting itself.

3. The belt is also moving this product up a hill on the outstocking section.

All of the above point to the fact that the belt has to be strong enough to resist all of these loads. If you are concerned, find the load rating of the belt, which in my part of the world would be "pounds per inch of width" or, more likely for a steel cable belt, load rating for the total width of the belt. I'll bet you it is substantial!

So if I was to consider attaching some sort of clamp to the belt near the head pulley...well, actually two clamps: one to the topside belt and one on the return side, I would not have a problem with having my crew pull slack back up to the head pulley, even if the slack was located at the farthest end of the belt. This is, of course, assuming that there is no load on the belt and it isn't jammed somewhere!

With the load rating of the belt in hand, you also know how hard you can pull on the clamps without damaging the belt. Unless the belt jams somewhere, I really don't think you will need to gradually move it up the conveyor from the takeup area.

If you have a bit of an engineering background, you should be able to calculate the pull you will need to move the belt slack up to the head pulley. It shouldn't be a heck of a lot more than the weight of the belt on the incline plus some allowances for friction on the horizontal section.

Hope this helps,

Jon.

PS: I'm curious--you sound like you are just starting out in the maintenance field or have been commandeered from somewhere else in the company to quarterback this job. Usually big outfits like what yours sounds like would have an experienced maintenance super who would eat this job up for breakfast. Care to give a little background on why the lack of maintenance support? No criticism intended...just wondering.

J.

Thanks for the detailed reply, I will start the calculation straightaway

Yes, I just started in this field and though the Supervisors and engineers are working this problem out, I thought I will grab some ideas and present during the meeting.

That frame you mentioned above, it will be bolted and welded to the conveyor structure, so how we will slide it sideways to lift it up using Crane if its welded?

The frame would be twice the width of the head pulley +/-. Once it was in place, half of it would be beneath the pulley and the other half sticking out one side of the pulley.

You would have to balance it so that the crane could pick it up in the center. (This frame would have to be engineered for the weight it was to carry and most likely of welded construction.)

Then, once the belt slack was at the pulley, bring the frame up on the crane hook and swing it sideways so that one half of the frame would move between the belt and the pulley. You now would have to fasten the frame to the head end of the conveyor. This is where I suggested welding OR bolting it into place. Again, an engineered design.

You now have a place to set the head pulley down on once you pull the bearings. You can then comealong the pulley sideways, out from behind the belt, and rig it for the crane to pick it up.

I say this frame needs to be engineered because you are dealing with substantial loads from the head pulley, and, just as importantly, eccentric loading on the conveyor structure when you move the pulley sideways to get it out from the belt.

Jon.

PS--I just realized that my discussion about the "frame" doesn't really explain what we're trying to do with it...It is premade, in a shop somewhere, and is brought to the side when the job is to be done to change the pulley. Get the belt slack at the head pulley and then lift the frame into place, temporarily fasten it there, and change the pulley. Remove the frame when the job is done!