A static belt cut compares the material loading on a measured section of stopped belt with the belt weigher’s corresponding loading indication. It can help investigate inaccurate readings, but it is a snapshot check with sampling and measurement limitations. It does not, by itself, prove the accuracy of accumulated tonnes across the conveyor’s operating range.
A belt weigher, also called a weightometer or conveyor belt scale, combines belt loading and speed to calculate flow and total. The test method needs to match the question: checking kilograms per metre is different from comparing a complete material batch against an independent reference mass.
Is it accurate, or has it been calibrated?
Calibration establishes how an instrument responds to a reference under specified conditions. Adjustment changes its response. A satisfactory reference check provides evidence for those conditions; the report should identify the method and limits rather than imply that every operating condition has been proved.
For example, static weights can check response to an applied load, while a suitably planned material test compares accumulated mass during a controlled run. A belt cut provides a different type of evidence. See test weights, calibration chains and material tests.
What is a static belt cut test?
The material is collected from a measured length across the full belt width, then weighed with a suitable reference instrument. Dividing the net material mass by the sampled length gives an average loading in kilograms per metre for that section.
The technician must establish how that sample relates to the instrument’s reading. A weigh frame responds over an effective weighing length, and a displayed value may be filtered or averaged over time. Material can move during stopping, and the loading at a nearby section may differ. A sample taken near the scale is not automatically the same loading the display represented before shutdown.
This is a description of the test, not a work instruction. Access to the belt and collection of material require a site-approved method, trained personnel and confirmed isolation with stored-energy risks controlled. The site assessment determines staffing, permits, access and handling arrangements. No material should be collected by hand from a moving belt.
What information makes a belt cut useful?
- The instrument readings and operating conditions represented by the test.
- The sample positions, measured lengths and relationship to the weigh area.
- Complete material collection within the selected boundaries, including fines.
- Container tare and a reference scale suitable for the sample mass and required resolution.
- Evidence of loading variation between samples and changes during stopping.
- The calculation, test limitations and criteria used to interpret the result.
There is no universal requirement for three one-metre cuts. The sampling plan needs to suit the material, loading distribution, scale geometry and intended confidence. Widely scattered samples can make a precise comparison unjustified, even if their average appears reasonable.
How is belt loading calculated?
Reference loading (kg/m) = net collected material mass (kg) ÷ sampled belt length (m).
If an instrument provides flow and speed instead of loading, the relationship is loading (kg/m) = flow (t/h) ÷ [3.6 × speed (m/s)], provided speed is non-zero and the values refer to the same operating conditions. Using the instrument’s own speed value in this calculation does not independently validate its speed measurement.
Illustration only: a sample of 91.8 kg collected over 2.0 m represents 45.9 kg/m. If a genuinely comparable instrument indication is 45.0 kg/m, the indicated difference is (45.0 − 45.9) ÷ 45.9 × 100 = approximately −1.96%. This shows the calculation; it is not an acceptance limit or proof of the system’s totalising error.
How should the result be judged?
First decide whether the reference and instrument values are sufficiently comparable. Then assess the difference against the agreed requirements and the uncertainty of the check. Sample variation, collection losses, length measurement, reference weighing and timing can all affect the conclusion.
A repeatable difference is a reason to investigate, not automatic proof that span is wrong across all flow rates. Check zero, speed, mechanics, signal behaviour and the test setup before deciding whether any adjustment is justified. Do not tune the scale to compensate for a poorly matched sample.
There is no fixed belt-cut pass band that suits every installation. Claims such as “within 1% is suitable for inventory” need to be supported by the site’s actual requirements and a test capable of assessing them. See zero, span, repeatability and tolerance.
When is a full material test the better choice?
Use a suitably planned material comparison when the question concerns accumulated tonnes under running conditions. The same defined quantity of material must pass the belt weigher and be independently weighed, with losses, tare and start/finish boundaries controlled. Testing should cover the operating conditions relevant to the intended conclusion.
A static belt cut may help locate a loading discrepancy where a full batch comparison is impractical. It should not be presented as an equivalent substitute for a running totalisation test. If the available test cannot support the required confidence, the report should explain what further evidence is needed.
Does a belt cut count as legal-for-trade verification?
No. This article describes a maintenance diagnostic check. Australia’s National Measurement Institute publishes NITP 6.5 for belt weigher verification, including the applicable material tests and other checks. A belt cut on its own doesn’t meet those requirements.
What happens after the test?
Accurate Industries records the findings and recommends the next step: further testing, a practical repair, recalibration or an upgrade where justified. If adjustments are made, the installation needs appropriate checks afterwards. See what happens during a calibration visit.
Frequently asked questions
Is a “live belt cut” the same test?
The term is sometimes used for collecting or diverting material while a conveyor runs. That requires purpose-designed arrangements and a controlled method; it is not hand sampling from a moving belt. Ask what method is actually proposed and what it will establish.
Can every belt weigher be checked with a static cut?
No. Safe access, material behaviour, conveyor geometry and the ability to obtain a representative comparison determine whether the method is practical and useful.
Can you help choose the right accuracy check?
Yes. Send the equipment details, symptoms, required performance and available reference arrangements to admin@accurateindustries.com.au, or discuss the test with Accurate Industries.
Need a manual for your equipment?
Talk to us about manuals for your equipment. Send the make, model, serial number and software version (a photo of the label is fine) and we’ll help you find the right document.