Idler spacing/ FOS Steel Cord Belting

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Posted in: , on 7. Jul. 2003 - 12:56

While studying some articles ,mainly on long distance conveyors, I have observed that ;

The carry idler spacing are kept as much as 6 m.What are the governing factors and limitations at the same time.

The F.O.S.of steel cord belting is as low as 4.5 :1. How is this achieved?What is the effect on life of the joints and belting itself?

These two can make hell of a difference to arrive at capital expenditure as well as on operational expenses.

Re: Idler Spacing/ Fos Steel Cord Belting

Posted on 7. Jul. 2003 - 04:55

Dear Mr. A K Bhatnagar,

The idler spacing depends upon belt tension, belt stiffness and over all economy. Unusual spacing choice will depend upon specific conveyor data, and can best be decided by conveyor expert / designer, with previous supporting data or by specific tests. A German company has supplied very long conveying system in Africa where they have used up to 4m pitch for carrying idlers and up to 8m pitch for return idlers. There will be also other long distance systems in various countries.

In a very long conveyor, the idler spacing will also vary along length as per tension situation.

There are specific guidelines for factor of safety (FOS) for belt. FOS is highly subjective to the sophistication in the design (i.e. how precisely each and every forces / strains have been accounted).

Bare minimum safety factor in combination with average design and average workmanship can be hazardous. FOS cannot be without context. So, the expert needs to see all the pertinent issues in real situation, while deciding FOS.


Ishwar G Mulani.

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

Email :

Tel.: 0091 (0)20 5882916