Position: A belt scale or belt scale controller is a piece of industrial control equipment used to gauge the mass or flow rate of material travelling over a possibly very long, and usually, a "cupped"conveyor belt, due to the weight of the mineral or aggregate being weighed. These are also known as motion Check weighers, dynamic scales, conveyor scales, and in-motion check weighers. Many check weighers are an active part of the process flow control of the conveyor line.
A belt scale replaces a short section of the support mechanism of the belt, which might be one or more sets of idler rollers, or a short section of channel or plate. This weighed support is mounted on load cells. The mass measured by the load cells is integrated to compute the mass of material moving on the belt, after allowing for the mass of the belt itself. belt scales generally include the necessary electronics to perform this calculation, often in the form of a small industrialized microprocessor system.
A belt scale is normally mounted in a straight section of belt, with no vertical or sideways curvature, and as close to level as is practicable. The weighed support must be aligned vertically and horizontally with the adjacent supports to avoid tensile forces in the belt skewing the measurement.
Outputs from belt scales are typically:
* pulses at predefined increments of mass
* an analogue signal proportional to the flow rate
In addition, some belt scale controllers will offer features such as driving an output to stop the belt when a predefined mass of material has been measured.
Belt scale controller uses include mineral and aggregate extraction, continuous mixing processes, and control of variable rate feeders.
