All of the above.

My approach would be to contact the belt Vendor. Goodyear and Dunlop used to publish information on selection of components for their belts.

Alternatively contact CEMA - they have guidance in both the 5th and 6th edition of the Belt Conveyor Manual. ■

Yes, yes and yes, contact your master slitter and ask what is the maximum allowable wrap angle with the belt you want to use.

lag the drive and head pulleys before hand and make sure you have training idlers every ten troughing and return idlers and a beater pulley at the tail pulley. ■

with respect to the 1000/4 I would advice a 630 mm pulley for the drive pulley and a 500 mm for the tail end pulley.

If there is a gravity take up the edge pulleys may have a diameter of 400 mm All thes dimansions are based upon normal conditions with normal safety factors.

In case there are a lot of pulleys in a compact conveyorsystem and a high load resp. low safety factor, the pulley diameters could be selected one size bigger.

A high safety however allows a reduction of the pulley diameter.

For the 630/4 I would advice a 500 mm drive pulley, a 400 mm tail end pulley and a 320 mm edge pulley for a gravity take up.

If you have a spindle tensioned conveyorsytem you have to be more carefull in the selection of the pulleys.

If you want a proper answer please give me more information.

I probably van help you with the entire system.

Kind regards

Johan Brands ■

In addition to my answer; with respect to the extreme thick rubber covers it would be better to make a choice for one size bigger pulleys.

Reducing the pulley diametrers is not an option.

Kind regards

Johan Brands ■

All belt manufacturers have publication on pulley diameter minimums based on fabric elasticity, number of plies, cover gauges, and applied tension with respect to the belts rating.

Since weft, warp, and other yarn design properties such as their polymers, have unique influences, along with skim coats and ply count, their systems must be individually considered. You will find differences between manufacturers. ■

Furthermore, the pulley diameter is selected to mate with the desired belt safety factor. Usually, the belt maximum stress ocurrs over the first or primary drive pulley. THis stress is composed of tensile (axial) and bending stresses. The pulley diameter controls the bending stress in the fabric carcas or steel cable.

Thus, with lower safety factors and/or high cycle rates (short plant conveyors) over the point of maximum stress, the pulley diameter may be select significantly larger than is cataloged.

It depends on how long a belt and splice life you wish to achieve. ■

Dear Mr. Sfccom,

For deciding the pulley diameter, one needs to know the carcass thickness, material of construction for the carcass warp. In a simplistic approach, one can decide pulley diameter by referring to DIN / ISO standard and see the pulley diameter corresponding to the carcass thickness. Such tables also relate pulley diameter to belt tension (maximum during steady state, in context of complete conveyor). Such tables indicate the pulley diameter in relation to usual / average application conditions.

For the conveyors of serious nature, pulley diameter selection also takes in to consideration whether the application condition is unfavourable, standard or favourable. This is again co-related to the transition distance, belt bending frequency, safety factors bare minimum value, etc. For example, if one intends to opt for somewhat lower safety factor then he will examine such possibility by using one step bigger diameter, and consequent saving in belt (such benefit will only realize if conveyor is very long).

Needless to mention, the pulley diameter being used should be larger of the as finalized above and as suggested by applicable belt manufacturer.

It has been observed that pulley diameter suggested by belt manufacturer happens to be as per their routine practice, because they are not putting their efforts in actual design of conveyor (unless they are paid for that). Therefore, the final selection of pulley diameter is the job of conveyor designer.

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.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■