Rice Lake BCi Belt Scale - Installation & Operation Manual Version 2.00 - Manual (Page 14)

8 BCi Installation & Operation Manual
Idler Spacing
The spacing between idlers should conform to the recommendations of the idler manufacturer and the Conveyor
Equipment Manufacturer’s Association specifications. A general rule of thumb is the idler supports the belt half
the distance from the previous idler to half the distance to the following idler as shown in the example below.
Figure 1-7. Idler Spacing Example
The number of weigh idlers required to accurately weigh the material being conveyed is determined by the
velocity of the conveyor belt. The scale born time of the material should be greater than 400 mSec. If the belt
speed multiplied by the idler spacing is less than 400 mSec, the idler spacing must be increased or multiple weigh
idlers must be used. Scale born time can be calculated with the following formula:
Scale Time = (Idler Spacing / Belt Speed)
Example: Scale Time = (4 feet / 8.33 fps) = 480 mSec
Belt Splicing
Belt splices also have a contributing factor in limiting the belt scale’s capacity. Mechanical belt splices can shock
load and damage load cells on high speed conveyors. Vulcanized splices are preferred for proper scale operation.
Figure 1-8. Mechanical Belt Splicing Example