Volume 11, Issue 2 (March 1983)
Mechanical Sampling with Stopped-Belt Accuracy
“Stopped-belt” samples are considered to be the standard of accuracy for mechanical sampling systems. Theoretically, stopped-belt samples do not disturb the stream of material in a manner deterimental to the obtaining of a true cross section of material from a stream of material. This paper explores the factors that create bias as a result of disturbing the stream flow. It outlines tests that can be performed on the material to be sampled and provides guidelines for the designing and operating of sampling systems that will enable them to obtain samples in a manner comparable to stopped-belt cuts. It is desirable to have sampling systems that are free of bias, provide samples that have a high degree of accuracy, and that are economical to own and operate.