IS THE BELT SPEED ACCURATE ON YOUR CONVEYOR BELT SCALE SYSTEM? The accurate weighing of bulk material on a conveyor is highly dependent on accurate speed sensing.
30 WHAT'S NEW IN PROCESS TECHNOLOGY - OCTOBER 2017
John Dronette, Siemens
C
ontinuous belt weighing is the process of determining the mass flow rate of bulk material being transported on a conveyor belt. It involves the determination of the instantaneous weight of the material on the belt and the linear speed of the belt. These two variables, determined separately, are brought together to produce flow rate or total weight. In many cases, people have found that the conveyor belt speed used by their belt scale system controller does not match the belt speed when checked by another method. The reported difference has sometimes been as much as 5%. This can have a significant impact on the accuracy of the mass flow rate of the material. There can be several factors that contribute to belt speed errors, including but not limited to: • incorrect scale factors used to convert the speed sensor signal to the belt speed • faulty speed sensors or speed sensor installation • an error in the comparison method used to check the belt speed reported by the controller. This article will focus on the first factor: incorrect scale factors used to convert the speed sensor signal to belt speed.
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