Sample Extractor

Abstract

A small quantity or sample of particulate material which is representative of a much larger batch of material, such batch in turn being representative of a large supply mass of the material, is extracted by feeding the batch to a dispensing head having two nozzles. The nozzles are alternately uncovered by a cyclically operated valve and a control is provided to variably proportion the residence times of the valve in its two positions so that the sample constitutes more or less of the batch. A second control is provided to increase the feed time for the batch as the residence time of the valve in that position discharging the sample is decreased in proportion to the residence time in its other position.