The use of exponentially smoothed data in continuous process control

Abstract

Continuous production processes characteristically do not result in production units which are well-defined from a quality control standpoint. Application of standard statistical quality control techniques requires sampling one litre, ounce or yard of product while the product is produced by the barrel, ton, or reel. Thus, direct application of quality control techniques is difficult. The possibilities offered by the use of exponential smoothing are analysed in this paper. Use of this method permits determination of meaningful control charts with a minimum of effort. The method is illustrated by applying it in the study of water pollution control.