TM 5-3895-374-24-2MODEL WBINSTALLATION, ALIGNMENT, & CALIBRATIONCONVEYOR WEIGH SCALE2-0 CONVEYOR EVALUATION2-1)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 formthe effective scale length must be of the same model and manufacturer and in good condition. Make certain thatall idlers are perpendicular to the belt and centered on the conveyor. The conveyor should have an automaticmeans 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 raterequired by the plant capacity. Stop the loaded conveyor. Carefully remove exactly 3 feet of material from thebelt. Weigh the material. Divide the measured weight by 3 to obtain the lb. of material loading per foot of beltlength.Example (using 150KG loadcell): 87 lb / 3 ft = 29 Ib/ftCalculate the proper idler spacing to get the ideal 175 Ib. of material on the weigh scale.175 lb / 29 Ib/ft = 6 feet idler spacingExample (using 75KG loadcell): 75 lb 1 3 ft = 25 Ib/ftCalculate the proper idler spacing to get the ideal 100 lb. of material on the weigh scale.100 lb / 25 Ib/ft = 4 feet idler spacingNote: Consider all factors. Try to use the ideal spacing to maximize accuracy. Other spacingscan be used but accuracy may be reduced. If ideal spacing cannot be used, considerchanging the belt speed. Contact your dealer for assistance.SYSTEMS Equip. Corp.Tel: (319) 568-6387WB, 921006, page 2(page 3 - 1268)