Abstract: An improved method and apparatus for monitoring, in real time, the quality of a flowing fluid stream and of automatically taking samples therefrom when the level of particulate matter in the flow stream exceeds an acceptable limit for a predetermined period of time. The apparatus includes a particle monitor and at least one three-way valve electronically linked via a programmable logic controller to the particle monitor. Not only is the latter an instrument for continuously measuring, on-line, numbers known as particle indices which are indicative of particulate matter concentrations in the flow stream, but also the particle monitor generates electronic signals. Both these signals and the particle index are proportional to fluctuations in the intensity of a light beam traversed by particles which are present in a portion of the flow stream during a fixed interval of time. Importantly, the particle monitor can detect relatively short-lived "spikes" in the level of 0.

Abstract: An improved method of monitoring condensate quality in a condensate return system and of controlling the level of particulate matter in the condensate flow so that when this level exceeds an acceptable limit, valves for discharging the condensate flow from the system open automatically or, alternately, an alarm is sounded. Utilization of the method facilitates the conservation of hot steam condensate for reuse in a boiler while preventing water contaminated with particulate matter from returning to the boiler, thereby protecting it from certain types of deposits and corrosion. The improved method includes measuring, on a continuous basis, relative numbers of particulate-type impurities under conditions in which rust or other particles large enough to block flow into a particle counter can be produced in sudden surges. Tests show that a suitable instrument for measuring the impurities under such conditions is a particle monitor.