TM 5-3895-374-24-2
MODEL WB
INSTALLATION, ALIGNMENT, & CALIBRATION
CONVEYOR WEIGH SCALE
2-0 CONVEYOR EVALUATION
2-1)
The conveyor in which the weigh scale is to be installed must be straight and rigid (especially in the scale area).
The conveyor troughing idlers should all be the same model from the same manufacturer. The 3 idlers that form
the effective scale length must be of the same model and manufacturer and in good condition. Make certain that
all idlers are perpendicular to the belt and centered on the conveyor. The conveyor should have an automatic
means of maintaining uniform belt tension.
2-2)
The effective scale length is made up of one idler before (approach), the weigh idler, and one idler after (retreat).
See drawing # WB00-00006 "Customer Weigh Scale Installation.
2-3)
Determine the most desirable location for the weigh scale. Consider the following factors:
2-3A)
Conveyor must be rigid.
2-38)
The belt must track in the center of the conveyor under all loading conditions.
2-3C)
Wind shields may be required to protect the scale from wind loads.
2-3D)
The conveyor must not be curved such that it tends to lift the belt from the scale area.
2-3E)
Scale maintenance; including ease of visual inspection, easy use of optional test weights, etc.
2-4)
Obtain the proper idler spacing at weigh scale. To do this, run the conveyor loaded at maximum aggregate rate
required by the plant capacity. Stop the loaded conveyor. Carefully remove exactly 3 feet of material from the
belt. Weigh the material. Divide the measured weight by 3 to obtain the lb. of material loading per foot of belt
length.
Example (using 150KG loadcell): 87 lb / 3 ft = 29 Ib/ft
Calculate the proper idler spacing to get the ideal 175 Ib. of material on the weigh scale.
175 lb / 29 Ib/ft = 6 feet idler spacing
Example (using 75KG loadcell): 75 lb 1 3 ft = 25 Ib/ft
Calculate the proper idler spacing to get the ideal 100 lb. of material on the weigh scale.
100 lb / 25 Ib/ft = 4 feet idler spacing
Note: Consider all factors. Try to use the ideal spacing to maximize accuracy. Other spacings
can be used but accuracy may be reduced. If ideal spacing cannot be used, consider
changing the belt speed. Contact your dealer for assistance.
SYSTEMS Equip. Corp.
Tel: (319) 568-6387
WB, 921006, page 2
(page 3 - 1268)
