Belt Weigher


Belt weigher / belt weighers

A belt weigher or belt scale 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 weigher 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 weighers generally include the necessary electronics to perform this calculation, often in the form of a small industrialized microprocessor system - EP52.

A belt weigher 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 weighers are typically:

pulses at predefined increments of mass
an analogue signal proportional to the flow rate
In addition, some beltweigher controllers will offer features such as driving an output to stop the belt when a predefined mass of material has been measured.

Typical extenso "single idler" belt weigher.

The belt weigher can either be single or multi idler and the weigh frame design ensures easy mounting in the conveyor.

Depending on the conveyor design and required accuracy, the weighbridge can consist of 1, 2 or 3 machined mild steel coated idlers.

Each system comes complete with an adjustable idler before and after the weighbridge.

The load cell signals processed by the EP52 controller are combined with the belt travel speed (measured by the tail drum mounted tachometer) to provide an accurate weight reading per unit time and totalised values.