Sampling
One should review the nature of the product to assess the type of variation that could occur. A free flowing solid is prone to segregation so, if this is a relevant factor, the first task is to establish how the containers are filled and the purpose of sampling, taking into account that the manner of emptying the container will alter the resulting distrubutionof fractions. A keypoint is whether the interest is in establishing the maximum degree of variation, or 'worst' condition of the product, or to secure an assessment of some 'mean' condition of the mass. Assuming a centre point fill and radial distribution, the radial location where there is an equal volume of material in the region outside the sample point to the region inside is 0.7071 of the container radius. Alternatively, the maximum segregation regions would be central and at the periphery of the container. If the fill point is offset fromthe centre, the maximum segregation is the further point away on the periphery to be compared with material under the point of fill ■
Powder Sampling
I need to ensure I take a representative sample from a 50kg barrel manually(dimensions 50cm diameter, 86cm height). The powder is free flowing. Is it sufficient to simply use a slot sampler and take samples directly in the middle of the container and two other locations? Do I need a grid or something else to ensure the samples are always taken from the middle and ,lets says, 10% to the middle and 50% to the middle of the container to reduce as much variability as possible? Also how would I ensure the sample is homogeneous after I've taken the sample and what volume do I need? Any help is very appreciated. ■