ONLINE PROCESS ANALYZERS.

Capability of onstream analyzers was greatly enhanced by off-the-shelf sample preparation systems and delivery systems presently available that have design scope as large as the instruments they feed. combination of analyzer with minicomputer further extends their application and seems to be the technique of the future and forms a basis for process control schemes. This system offers online analysis capability that is at least equivalent to results from a quality-control laboratory. Further, it has the advantage of performing at a frequency completely impractical for a quality-control laboratory. Examples of analyzers reviewed include spectrophotometric ultraviolet, visible light, near-infrared and infrared analysis, emission gases' oxygen content, process stream moisture content, pH determination and liquid and gas chromatography. Key to online process analyzers' success is a well-designed maintenance program. Basic to this program is a technically competent support group that implements a preventive maintenance routine.