Guide for Implementing Conveyor Belts Scales

Dynamic weighing or continuous weighingis used to calculate the flow of an uninterrupted stream of material. This continuity of charge constitutes the main difference with the previous modes. Due to the displacement of the load, the weight to be measured constantly varies on the weighing table and the continuous weigher will integrate these variations in weight over time, hence its name of integrating scale. As a corollary, any continuous weighing system measures the weight but also the speed of movement of the product. This is the case, for example, with belt scales, weighing screws or scales called “with conveyor included”. Continuous instruments are defined by their capacity in tonnes / hour (t / h) and their precision which is expressed in relative value and no longer in absolute value. For example: T12 - All-round scale - 900 t / h +/- 1%. The integration of the weight makes it possible to accumulate the past tonnes and explains that a continuous indicator is called Continuous Totalizer. In regulated use, it falls into the category of IPFA.

Discontinuous weighing is halfway between static weighing and continuous weighing. Like continuous weighing, it performs on-line weighing, its precision is expressed in +/-% and not in absolute value, and it accumulates the weighed weights. Like static weighing, the load is stationary at the time of weighing and the weight is measured at stability achieved. It therefore has the advantages of both types of weighing: high precision of static weighing and uninterrupted material flow of continuous weighing. In practice, it creates a momentary interruption of the flow to carry out its weighing. For this, it needs a buffer hopper upstream and downstream of the scale. In other words, it requires a weighing tower. Because of this heavy investment, discontinuous weighers, commonly known as "circuit scales", are especially suited to high value products or high throughputs such as the loading of phosphate ships. However, their use in quarry remains ad hoc.

TELEMETRIX also masters a weighing solution in the case where the conveyor is bidirectional.