Greetings and salutations,

An aluminum "sample splitter" or sample riffler as it also refered to would allow you to get a get sample in your case I think.

It would amount to taking the first sample off the truck, a second sample a bit later when the hopper is 3/4 full a third sample when it is 1/2 full, a forth sample when it is a quarter full and the last sample when the truck is nearly empty. The process then becomes one of splitting and reducing and reducing of the sample until it is done.

A sampling scoop is placed briefly under the product stream and removed and then the sample is set aside in a bag for later sifting. doing this five times while the material is unloaded and split after the truck is unloaded would allow you to obtain a representative sample.

I have attached a representative passive sample splitter from "Laval Labs" for you to view.

lzaharis

Attachments

sample-splitter-040g022 (JPG)

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It is not uncommon to discharge into a holding bin while awaiting the results of sampling. If OK then it's moved to the main store, if not it can be loaded back into the lorry. ■

Dear friend,

what is the largest grain size you have? What is your problem with the zone samplers and large grain sizes. We do have extra big zone samplers up to 2,5 m length and 50 mm dia.

Maybe this would be a sollution for you. For more details please see:

http://www.buerkle.de/en/shop/jumbo-sampler.html ■

Although the proportion of the constituent particles sizes are not given, the particle size range would indicate that the bulk material is prone to segregation. Assuming that the acceptance criteria is based on particle size composition, there is a fundamental quality problem in assessing the composition of a uneven large mass as the deposition of the fractions will depend largely on the mechanics of loading the material into the container. Taking samples without a general understanding of how the material will behave is working blind and many samples would have to be taken to derive an accurate assessment of the whole.

Assuming that the supply to the container is reasonably homogenous, from a knowledge of the container dimensions, the procedure of filling and an understanding of the relevant segregation mechanisms, it should be possible to deduce the pattern of filling and the broad structure of how the composition is likely to vary throughout the volume. It may be reasonably assumed that a rectangular body will tend to be filled centrally along the main axis, between centres that are spaced equidistant one half of the width from either end. The absence of fine fractions will usually result in repose flow mechanisms that, from a combination of sifting. Percolation, inertial and capture effects result in an avalanched layering of fractions, with a predominance of smaller particles resting in the centre of the pile. The boundary contour along the length of the container will provide a guide to the fill point(s) and hence the probable distribution of fractions, whilst samples taken from just below the surface should reflect the radial distribution of the constituents. A screw boring that collects a ‘core’ from differing layers, if mixed then divided, should give a representative sample of the depth at chosen radial positions from the point of fill. The geometry of distribution can then be calculated from the measured angle of poured repose of the mixture. The general pattern of deposition of typical mixes can be determined by small models in a two dimensional transparent wall cell. See video on web site www.ajax.co.uk, which also illustrates segregation mitigation techniques on filling and discharging hoppers. My book -'User guide to segregation', published by The British Materials Handling Board, sets out the basic background to these aspects and gives guidence on mitigation and correction techniques.

No limited sample technique will perfectly predict an irregular pattern of variation, but these basic principles should allow better results to be calculated than a similar number of random or systematic samples taken without consideration of flow regimes and segregation mechanisms. ■

With this new sampling device you'd take the samples in the descriped manner with ease!

https://youtu.be/Dkxjgf23sAo

With best regards

Felix Obermeyer ■