Rice Lake BCi Belt Scale - Installation & Operation Manual Version 2.00 - Manual (Page 15)

BCi Installation & Operation Manual - Introduction and Overview 9
1.4 Selecting a Mounting Location
It is very important to select the right mounting location for the scale carriage along the conveyor structure and
the location of the speed sensor. There are several factors that must be taken into consideration when selecting a
mounting location. Those factors will determine the overall long-term and short-term accuracy you might expect.
Those factors include the following:
• Tension
• Uniform Belt Loading
• Single Load Point on Belt
• Material Slippage
• Convex Curves
• Concave Curves
• Trippers
• Speed Sensor Mounting Location
• Electronic Wiring Location
• Speed Wheel
• Troughing Angle
Tension
The transfer of weight along the conveyor belt can be greatly affected by belt tension. By locating the scale
carriage in an area of the conveyor with the least amount of tension, the scale will be more accurate and achieve
better performance. An ideal location to mount the scale carriage is near a tail section of the conveyor, but far
enough forward so as not to be influenced by infeed skirts boards, etc. Figure 1-9 illustrates the proper belt
tension.
Figure 1-9. Proper Belt Tension Example
Uniform Belt Loading
It is desirable that the belt loading be as uniform as possible to prevent unequal shifts in material. To minimize
surges or feed variations, hoppers should be equipped with depth limiting gates or other flow control devices
such as a feeder.
Single Load Point on Belt
On high accuracy installations, the conveyor should be loaded at one and the same point. This assures constant
belt tension at the scale during all loading conditions.
Material Slippage
The belt scale system processes belt loading and belt travel to arrive at an accurate weight. Product speed must be
equal to the belt speed at the scale. So the conveyor speed and slope should not exceed that at which material
slippage occurs. This is typically less than a 20% pitch for most materials.
Convex Curves
Conveyors that have convex curves should be avoided or the scale should be located in a section of the conveyor
that is not affected by the curve.
Convex curves are permissible at a distance of 20 feet or a minimum of five idler spaces beyond the scale area
idlers.