The head end of a conveyor with a tripper usually never sees any burden & so it is possible to pitch the idlers at, or near to the return idler pitch. This also implies that training trough idlers would be rather wasted. Why trough a belt when it isn't loaded? Any off-tracking will be what comes off the bottom bend pulley of the tripper, regardless of its source.

It would look better with 2 vee returns on the top strand end with, as you say, guide rolls to prevent belt damage as well. ■

Hello Cormier,

You have only 400 feet long conveyor, mostly with textile fabric belt. So, one option is to provide crowning for pulleys, which will tend to align the belt.

The conventional pivoted self aligning idlers are not placed within the tripper travel zone because the belt from tripper when landing on the conveyor, may land on the side vertical rollers of the self aligning idlers (when misaligned belt is reaching to the conveyor level). This situation can damage the belt.

People do provide self aligning idlers beyond the tripper traveling zone, at head end as well as tail end. This is the routine specification by buyers in India.

One should try to improve the correctness of the installation of the idlers and conveyor. Generally the belt will run aligned if the various alignments are reasonably good. The belt troughing of 30 degree or more does improve the alignment of the belt.

The earlier respondents have also given certain suggestions based on their experience.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Pune, India.

Tel.: 0091 (0)20 25871916 ■

I can't believe that you can't train or align a 400 foot long conveyor without trainers. We have conveyors over 4000 feet long with no trainers. It all comes down to proper installation and good alignment of all components.

In a short conveyor the alignment of pulleys to the frame and each other is most important and then the squaring of the idlers to the frame. If this is done correclty then there is no need for trainers. The other condition is a straight splice of the belt. Final adjustment is made by "skewing" idlers or another term is called "knocking" idlers to train the belt during running empty and running full.

Loading off center of the belt can also cause mistracking. I would look at all of those before I wasted money on trainers. A trainer is a lazy way out if you ask me. ■

Originally Posted by Cormier

Hello all,

I'm new to this and in need of advise.

Are there any written rules on spacing and distance from end pulleys of self-align idlers?

My customer has a 60" conveyor, roughly 400' long with a tripper on it. The problem is that they get uneven loads at times. Because of the tripper, they wanted to install a trough tracking idler at the end of the conveyor, about 20' from head pulley. I didn't think it was such a good idea, but I can't find any documentation to back me up. They have some V-return tracking idlers.

Should they use fixed guide rolls at the ends to prevent damages to the structure?

Thanks in advance,

One tracking Idler shoud be just after tail pulley and one just before head pulley and others at equispaced @15 m.

K. OBI REDDY.

for any assistance contact k.obireddy@gmail.com ■

Originally Posted by Cormier

Hello all,

I'm new to this and in need of advise.

Are there any written rules on spacing and distance from end pulleys of self-align idlers?

My customer has a 60" conveyor, roughly 400' long with a tripper on it. The problem is that they get uneven loads at times. Because of the tripper, they wanted to install a trough tracking idler at the end of the conveyor, about 20' from head pulley. I didn't think it was such a good idea, but I can't find any documentation to back me up. They have some V-return tracking idlers.

Should they use fixed guide rolls at the ends to prevent damages to the structure?

Thanks in advance,

HI there, we maufacture belt tracking systems called Sureguide, www.sureguide.co.za, it is a well know fact that 80% of all belt tracking problems occur on the return side, so firstly I would install a return idler tracker about 5 times the belt width from the tail pulley to correct any misalignment before the load zone, after that I would suggest that you install a TSG trouging sureguide at about 3m after the load zone to steer the belt central in the instance that the load is off-centre. As a rule of thumb you should install a SG sureguide return every 40m depending on the severity of the tracking problem, generally if you would have an incline belt you would install a return tracker before the tail pulley, lead pulley, and before and after the gravity uptake, extra TSG's can also be installed before area where spillage is taking place. In an ideal world we would not have any tracking problems but due to financial and manpower constraints it is not always posible to apply sensible practice. hope it helps ■

Please do not do it. The local center stress, at the two roll junction will cause the belt rubber to separate from the center cable. Witnessed this on a large BHP installation in Australia. They were blaming the belt turnovers.

We convinced BHP the culprit was the Vee roll transition configuraton was not acceptable. There were a number of fixes proposed, including applying a small centler roll to reduce the benidng intensity at the idler junction.

Best not to use 2-roll Vee on high tension zones. ■

Louispangjang,

A further note on the BHP high tension two roll Vee idler configuration, the rubber spearation caused the belt to divide into two pieces. ■

I agree with Gary, a properly designed belt with good idler and structural installation tolerances, and a proper tail zone loading configuration does not need any training rolls. We have designed hundreds of km of overland belts with no traiining rollers.

If in the future, you have earth settlement, the frimae can be easily adjusted to bring the idlers and belt back into balance and centered.

Most training roll assys are counterproductive and do not enhance tracking until the belt is at an extreme misalighnent. ■