Laboratory Testing & General Mineral Processing Engineering

Laboratory Testing & General Mineral Processing Engineering 2017-03-23T09:50:31+00:00
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Weightometer Calibration Accuracy (2 replies)

Helena Russell
6 months ago
Helena Russell 6 months ago

Hello everyone, what methods do you use to verify your conveyor belt scale’ accuracy of calibration?

I'm familiar with belt cuts as it is the only method i have had practical experiences with. Recently, we did a 30 meter belt cut on a 700 meter length belt. The belt reading showed about 35% reduced tonnage relative to the belt cut. This is a huge difference and I'm just wondering what you think could be the problem.

I heard some compare a truck weight with material in other weighing system & others use a weighted wheel riding on the belt for a given length belt then calculate the total and compare with scale weight.

What is the best method? How do you calibrate a weight-scale and check its accuracy?

Sugar Watkins
6 months ago
Sugar Watkins 6 months ago

There are various methods available. Each has its pros and cons. Calibration weights placed on the weigh frame, Calibration wheel or chain, Material testing. Calibration weights are the same as the normal calibration method in most cases. Calibration wheels or chains is a good method if fitted correctly and maintained frequently to maintain its certified parameters. Material testing is not always possible because of various reasons, but is easily accepted because it gives an immediate reference to an external source.

Some think that belt cuts are acceptable with ball mills when the P80 of product on the belt is from a few millimeters to say maximum 40 mm. Consistency of feeding on to the belt is essential. Do a few cuts short intervals apart so you get some statistical data. For SAG mills (particle 150 mm) you would have to take a few meters length and it becoming quite an exercise (say you have 4-8 x 45 gallon drums you need to weigh accurately).

If trucks or loaderite is more accurate that your belt scale then problem is with your belt scale, conveyor, operations or combination of. From experience belt scales correctly installed, maintained clean and without overloaded belts, are accurate better than 2% (the scales are calibrated with chains every month but not fewer than once every 3 months).

I personally like the roller or chain method. In my opinion the only way to calibrate weightometers is to use a chain. Checking from time to time using a truck is useful providing the truck load is sufficiently large > 100 tons.

5 months ago
KavaliJ 5 months ago

Could you send me your data? I'd like to have a look before I can provide some feedback.



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