Optimizing Idler Spacing: Balancing Support, Efficiency, and Maintenance on Conveyors
The spacing between the rolling components significantly impacts the support and shaping roles of idlers. Idlers that are placed too far apart fail to adequately support the belt or maintain its desired profile. Conversely, positioning idlers too close together enhances belt support and profile but escalates conveyor construction costs and may increase power consumption. Typically, idlers are placed close enough to support a fully loaded belt to prevent excessive sagging between them. Excessive sag causes the load to shift as it traverses each idler, leading to increased belt wear and power consumption, as well as encouraging material spillage. CEMA has published tables detailing recommended idler spacing for applications outside the loading zone.
Return idler spacing is determined by belt weight since these idlers support no additional load and sag-related spillage is not a concern on this side of the conveyor. Typically, return idlers are spaced 3 meters (10 ft) apart.
In the skirted area, the traditional method to enhance belt support and reduce sag under a loading zone or elsewhere along the conveyor is to increase the number of idlers. By increasing the idler count within a given space—thus reducing the space between idlers—the potential for belt sag is minimized. Idlers can usually be positioned so that their rolls are within 25 millimeters (1 in.) of each other. However, this approach has its challenges. As idlers are packed more closely, servicing them becomes more difficult. Idler sets are typically maintained by laying the framework on its side to lubricate or replace rolls. With closely spaced idlers, there's insufficient room to lay the idler set on its side for maintenance. Accessing one set of idlers may necessitate removing one or more adjacent sets, potentially causing a chain reaction of disturbance.