Fixed tail drums are occasionally fitted with brakes and in such cases a lagged drum might be mildly advantageous.

If there is a turnover twixt the drive and a GTU then the drum will be exposed to the dirty side and lagging might be required. This condition must be considered in the transfer of burden between bidirectional conveyors especially if there are tail end drives. ■

It all depends on the conditions and the design intent. For example in the mining operation that I came out of we did not use any lagging except on the drives. We did on some occasions use some ceramic lagging where we had some heavy wear issues on some pulleys.

So to answer your questions no it is not required unless the design or condition requires it as in examples of what John describes for a few. ■

In some countries and some mines pulleys are not treated as a consumable but instead as an item that can be maintained. Having lagging on the pulley gives you something that can be replaced instead of scrapping the pulley body when shell wear does occur.

Even running on the clean side of the belt the shell/lagging will wear, particularly in installations with short transitions.

It will come down to an economic decision: Do you want to change the pulley or the lagging, how much does this cost, and how often will they need to be changed?

Regards,

Andrew Hustrulid ■

A conveyor is a piece of process equipment. Much process equipment is designed with wear allowances and fouling factors. Why not do the same for non-driven conveyor drums: if we're so concerned?

If I had my time over again I would seek to a apply a wear allowance to all but the wettest driving drums as well, if the wrap couldn't take it. At a recent mining show in Jakarta a leading vendor of ceramic liners agreed with me that the glue was the critical component. ■

Hi,

Adding extra steel to the pulley shell to accommodate wear can and is done, at a cost, if requested by the customer.

Some mines plan that the pulley body (shell + end discs) will be refurbished once or twice and will increase the shell thickness 3 to 6mm so that the shell can be machined and returned to a flat surface.

Other mines will run the pulley to near failure and replace the whole thing. It comes down to where it makes sense to spend the money.

Regards,

Andrew ■

Hi all -

I too agree across the breadth of the commentary. Applications for pulley lagging are varied based on may factors, including environment, loading conditions, cleaning efficiency, etc. I would simply add that pulley lagging is not a magic bullet and will not solve all ills - and in some cases, will cause many ills. This is especially true at the tail pulley. Misguided application of a lagging at the tail can result in severe damage to the belt including greatly reduced wear life on the pulley cover. As the panel has stated - properly designed pulleys, with shell thicknesses gauged as per the application, will extend shell wear life. ■