Bulk Handling Technologies - Conveyor Idler Roller

As well as supporting the belt, the idler frame assembly develops the required 'troughing' of the belt to suit the application.  On a belt conveyor, carry idler frames are typically installed as 3-Roll assemblies, with 35 or 45 degree 'wing' rollers to maximise carrying capacity. 

Due to the higher tensions and shorter span between pulleys on belt feeders, idler sets on belt feeders often have rollers arranged to create a long flat centre support, with short 20 degree 'picking' wing rollers to help contain product which escapes under the skirting.

?Selecting the correct idlers for an application needs to consider the supported load, expected impact loads and rotational speed, and should also take account of material properties, maintainability and commonality of spares if a site has multiple machines.

On belt feeders, it is often required to install specially designed impact rollers in the feed zone.  Impact rollers typically have rubber lagging or discs which help absorb impact forces generated when material is loaded on to the belt from height. 

These idlers often require larger shafts and bearings to cater for the expected loads.  Depending on the application, impact beds can also be considered.  These typically consist of impact bars with a low friction surface, allowing the belt to slide.  Consideration must be given to the increase in belt tensions and also the generation of heat due to sliding impact beds.

To improve maintainability, particularly on larger belt feeders, idlers can be mounted on retractable support frames.  This allows maintenance personnel to slide the idler assembly out into the maintenance corridor for easier replacement, rather than risking injury by reaching under the belt and lifting the heavy frame out in and awkward position.