BK Belt Weigher

How do you choose between the three models?

The three BK models work on the same principle; they differ in the load they can carry and the conveyor size they fit. On all three, belt speed is at most 3 m/s and conveyor incline at most 18°. The differences can be summed up as follows:

• BK-1000: belt width up to 800 mm, 10–100 kg load per metre, 500–1000 mm idler spacing, flows up to 1000 t/h
• BK-2000: belt width up to 1000 mm, 10–200 kg load per metre, 500–1500 mm idler spacing, flows up to 2000 t/h
• BK-6000: belt width up to 2000 mm, 10–550 kg load per metre, idler spacing up to 2500 mm, flows up to 6000 t/h

The flow figure alone does not decide the model; the real criterion is the load the belt carries per metre. Finding it for your own conveyor is easy: divide the hourly flow in tonnes by the belt speed in m/s and by 3.6. For example, on a belt carrying 1200 tonnes an hour at 2.5 m per second, the load is 1200 ÷ (2.5 × 3.6) ≈ 133 kg/m. That exceeds the BK-1000’s 100 kg/m limit and falls within the BK-2000’s range. The flow limits in the table come from the same calculation: 100 kg/m at 3 m/s is roughly 1080 tonnes an hour.

The lower limit matters too. On all three models the minimum load per metre is 10 kg. If the belt runs for long periods with very little material, for instance a flow below 72 tonnes an hour at 2 m/s, the measurement drops under that limit. This is why we need both the lowest and the highest values of your flow.

Retrofitting to an existing conveyor

The BK does not require building a conveyor from scratch; it can be added to a running line. The system has three parts: load cells carrying the idlers in the weighing zone, a sensor that reads belt speed, and an indicator that combines the two and calculates the result. Before retrofitting, check these four values on your conveyor:

• Belt width: must be below the upper limit of the chosen model
• Belt speed: must not exceed 3 m/s; if speed varies via a frequency inverter, the highest value counts
• Incline: must not exceed 18° in the weighing section
• Idler spacing: the distance between carrying idlers must fall within the model’s range

You can take these values yourself with a tape measure and by timing a few belt revolutions. Photos of the conveyor and a rough side-view sketch also help to locate the weighing zone.

What does the indicator show?

The BK indicator can show the same measurement in different units: tonnes per hour (t/h), kilograms per hour (kg/h), kilograms per metre (kg/m), total kilograms, belt speed (m/s) and per cent. Tonnes per hour is used to follow production pace on a crushing-screening or loading line; kilograms per hour gives a more readable value on low-rate feed lines. Being able to see load per metre separately provides a practical check: if the value leaves the chosen model’s range, the belt is overloaded or carrying too little. An unexpected drop in the speed reading flags early that the belt is slipping or the drive has a problem.

The indicator is equipped with a 32-bit processor running at 72 MHz or more, a high-resolution Δ-Σ analogue-to-digital converter and a 160 × 32 dot-matrix LCD. Its housing is wall-mounted; being resistant to corrosion, water, dust and impact, it suits use on a dusty quarry site or in a control cabinet next to the conveyor.

Calibration functions and reporting

Set-up and calibration are done digitally from the indicator’s menu. Three functions stand out. Automatic zero tracking follows slow drifts of the zero point while the belt runs empty, limiting the effect of things like fine material stuck to the belt on the total. Speed calibration makes sure the pulses from the sensor are converted to the true belt speed. Belt length calibration lets the indicator recognise one full revolution of the belt; since a belt’s own weight varies along its length, taking empty-belt readings over full revolutions makes the result more stable.

The BK records material arriving from the mine or production line continuously and reports by shift, day, month and year. Production efficiency is thus tracked without a separate weighing step and the time it would take. A worked example: at an average flow of 450 tonnes an hour, a shift that runs 7.5 hours after stoppages produces 3375 tonnes. This figure appears directly in the shift report; at month end the same records can be compared with the dispatch total from the truck scale to follow stock differences.