Rice Lake BCi Belt Scale - Installation and Operation Manual Version 2.03 - Manual (Page 19)

Installation and Operation Manual - Introduction and Overview 13
1.4.11 Troughing Angle
The use of idlers with steep troughing angles causes many problems. Not only does the bean or catenary effect of
the belt become more pronounced as the toughing increases, but the effect of idler misalignment is amplified as
well. The graphics below show an example of a correct and an incorrect troughing angles.
Troughing angles of 35 degrees or less are preferred for all high accuracy installations. Troughing angles of 45
degrees are acceptable under certain conditions.
Figure 1-14. Troughing Angle Examples
1.5 Poor Choices for Belt Scale Installations
There are several instances where a belt scale installation would not be the best solution. The following list
points these out.
• Conveyors with multiple loading points.
• Conveyors with convex or concave curves.
• Conveyors with different stringer members in troughing rolls.
• Conveyors that do not receive periodic inspections and housekeeping.
• Conveyors where there is no facility to conduct a simulated test.
• Conveyors that are used in cold weather that are not installed in a heated conveyor gallery.
• Tripper conveyors
• Radial stacking conveyors
• Applications where the belt scale results are compared with a marine draft survey.
• Applications where the belt scale weighment is subject to certification but the conveyor does not meet
Handbook 44 requirements.
• Applications where plant personnel are unwilling or unable to perform routine conveyor maintenance.
• Conveyors with more than 2-ply belting
• Conveyors that are installed outdoors, but are not equipped with a cover over the carry belt.