Most raw materials and manufactured products are sampled by some method for purposes of quality control. Our area of interest lies in extracting material samples from conveyor belts, chutes, launders or flumes, vibratory feeders, pipeline, trucks or trains. A representative sample is where every particle in the lot sampled is equally represented. The procurement of a sample from a material stream is analogous to passing a water glass underneath a stream of tap water. As the glass moves from right to left at a fixed rate of speed, a sample is left in the glass. This is a  representative sample of the conveyed product which we are trying to obtain.