Hi Gareth,

We can take a simple method, but we have to know the belt width and material weight that will be conveyed (depending on the density) first.

You can have a look at CEMA for the "suggested spacing".

Regards,

Endri ■

Dear Gareth,

Please have a look at Belt Conveyors for Bulk Material, Chapter 5, Conveyor Idler, Idler Spacing.

Regards,

Endri ■

Dear Administrator,

Title: Belt Conveyors for Bulk Materials Sixth Edition

Published by: the Conveyor Equipment Manufacturers Association

Year: 2005.

Regards,

Endri ■

Paper 2 tells a practising conveyor designer nowt of any use. Paper 1 is absolutely right in the critique of the Standards available and the respected author has published much & often with regard to modernisation of the business. Unfortunately there is no incentive to rewrite the existing Standards to incorporate the latest developments.

I personally think that the existing Standards were ill founded, unsubstantiated by test results and thrown together by a set of camel/horse committees in the days when if you sounded clever enough then you must be. Although I'm no spring chicken I long for a realistic authoritive reappraisal of the Standards which we are all lumbered with in heavy engineering (eg ASME 8 does not recognise the existence of laser/vacuum/ultrasonic welding techniques even though they would produce stronger nozzles. Why? Because the QA & AI functions would have to learn something new.) Obsolete Standards are fundamental in ridiculing our work in the public eye. As long as a bridge is to Standard it doesn't necessarily have to withstand pedestrians forcing it into resonance.

So why worry about idler spacing optimisation? If you use the Standards they are obsolete and probably conflict with the manufacturers' recommendations. If you use the manufacturers' data and it goes wrong then you are out on a limb.

However you pitch the idlers they will be too close for somebody and too far apart for others. If they fail you can always blame it on poor maintenance. I'd go for midway between the Standard and the manufacturer's pitch variation if there is one.

CAPEX & OPEX considerations are irrelevant in the Northern Hemisphere where energy costs are unpredictable and the energy availablity itself is a political issue. Just make sure the idlers line up with the holes in the steelwork. ■