I would hesitate on this simply due to the duty cycle and pressure expressed on the resin shell and the other big problems are heat, and bearings and bearing surfaces how are the bearing houisings going to be cast into the the shell?, and any troughing idler will need a connecting hose/fitting to the other idlers in the trough-three plus idlers per set/depending on the width of the belt etc. not to discount the need for an idler carrier that will be used for cable or streel supported belt which also takes a huge amount of pressure due to the weight of the belt and ore and take up pressure. the idler carriers have to be able to be smacked with a heavy hammer (2-5 pound) to align them too.

If my memory is right the pipe tubes used to cut shell blank for shells are .283 or greater in thickness. the other worry is breakage as they go through a lot of use and abuse as the idler sets are thrown around dropped , carried in loader buckets-at least underground anyway/possible chipping and tearing th econveyor belt is another biggee. my self I am a firm believer in capsule pipelines and to prove that google (karasawa mine) to see one in use since the early eighties. I cant stand belt conveyors simply from my 22 years of maintenance and repair experience with them.

You might seriously consider talking to the Van Gorp folks-(the pulley people) about making a resin cast beater pulley for tail pulleys. castiing is much simpler than welding a beater pulley together.

My two cents from the "soon to be frozen eastern wilderness @ 1140 feet above mean sea level". ■

Any time I have used a plastic sleeved roll, it is to prevent material from sticking. The sticking can be made worse by corroded steel but if the conveyor runs more or less continuously, the material handled would have to be chemically aggressive to cause the rolls to suffer from corrosion I would think.

There used to be a solid plastic roll idler produced in the USA, I think it was made by North American Idlers, who I couldn't locate last time I needed one.

If a 5" dia steel roll had a 1/4" thk shell it would weigh about 1.2 lb/in length. The steel shell tubing would cost about $.70 to $1.00/lb depending on quantity purchased.

Biggest problem I see will be the connection between the shell and the end cap which must have some steel to hold a bearing. I have seen similar problems with this connection on small unit handling conveyor rolls.

The pultruded plastics are great and have a +20 year history in some applications like replacing wooden drag flights in sewage collectors. I have just done some work with a concrete utility pole manufacturing application, and I think that market is ready to replace wooden poles with new materials like concrete and composites.

The bulk handling industry is brass bound by tradition and my feeling is it will adopt new concepts like this reluctantly unless the results are spectacular and too hard to ignore.

Conclusion, if the company doesn't put all their eggs in one basket, they might do OK. ■

The use of polymer sleeves in idler rolls is very common. Specific uses are in highly corrosive environments. Many threads have detailed the noise reduction afforded by a sleeved roller.

Fully polymer rollers (i.e. without an internal steel shell) are realtively uncommon. There are some examples in the market-place such as that offered by Lorbrand or the Yelloroll (utilises standard Yelopipe patented material) .

The type of shell material proposed sounds like it could be efficiently used.

A major concern would be the creation of a suitable bearing housing - many ploymer housings systems have failed due to excessive flexibility, resulting in displacement of the bearing assembly during operation.

With regard to shell wear - the shell wear is highly dependant on how well the roll turns i.e. minimal speed ifferential between belt and roll surface. There are many steel rolls which show a less than 0.5mm wear after 10 years operation. Abrasive wear of the shell of a 'sticky' roll could occur within weeks (or hours).

Note that the effect of the material on the belt covers is also a factor.

FMC are producing rolls with this 'new' material ? Great stuff - I hope that they will share their results with the forum. ■

Plastic cast rolls have been around for decades. The early Rise-Louise (sic) German firm did a good job of this.

Rulmeca (sic) now associated with Melco RSA did or does manufacture a blue casting? Maybe Adi could shed some light on this.

Noise and corrosion are big issues today. Noise for quiet running conveyors near suburbs. Corrosion for seaside and acid leach copper operations. You might try discussing this with TNT (Terra Nova Technologies, a division of AMEC) located in San Diego, CA. They make grasshopper conveyors for heap leach systems all over the world. Heap leach components must be sulfuric acid resistant.

Big negatives are fire and wear. If you can overcome these, and sell at a decent price point, many will come to your party. ■

With regard to the abrasion resistance of the Yeloroll:

A 'standard' test which was conducted at MELCO on various products was to apply an abrasive force (piece of sand paper) to the roating surface of an idler roll. Constant force was applied by means of springs and the same grade of sand paper was used.

The test was run for a time period of 50 hours and then the amount of wear on the shell was measured.

Interestingly the Yeloroll performance was considered inadequate when compared to HDPE/PVC. The reason? The Yeloroll has a relatively hard outer 'skin' - as soon as this skin is abraded the sublayers are rapidly eroded. As I remember the sample was removed from the test rig for fear that the shell would be totally worn through prior to the end of the 50 hour test period.

I will forward this thread to Melco's marketing wing - perhaps they will share results of their abrasive testing.

I have also noted significant abrasive wear of YELOROLL product in an underground hard-rock environment where the shell was abraded due to contact with spillage.

Regards,

Adi Frittella

AFRIPP PROJECTS CC ■

Are there any further advancements on the topics discussed within this thread?

The above conversations are of great interest to me.

Regards,

Ryan ■

Originally Posted by lzaharis

......... I cant stand belt conveyors simply from my 22 years of maintenance and repair experience with them.

.........

My two cents from the "soon to be frozen eastern wilderness @ 1140 feet above mean sea level".

After my recent experience with French nickel mining attempts I am coming round to the same thought.

Belt conveying is often there just for the sake of it. "Let's explore a new deposit and suggest an even longer conveyor to make us look clever."

Happily out of it. ■