Met One, Inc.

Louis J Petralli

An apparatus for detecting and counting particles in a gas stream flowing at a preselected rate, wherein the apparatus includes a multi-tier inlet manifold and a plurality of sensors. The inlet manifold divides an aggregate sample flow into a plurality of substantially identical partial sample flows. Each partial sample flow enters one of the functionally duplicative sensors and is intersected by an incident beam to define a view volume. Particles contained within the partial sample flows scatter light as the particles pass through the view volume. The scattered light is directed to a photodetector which provides a signal having characteristics corresponding to the sensed light. Particle detection in each view volume is operationally independent of the others, but the information is combined to provide a total particle count of the aggregate sample flow.

Split flow uniform multisensor detection

An apparatus and method for particle detection which includes a plurality of sample regions. A sensor body has internal walls which define spaced apart sample regions, with each sample region having an inlet port and an exhaust port. An aggregate sample flow is divided into partial flows which are directed from the inlet port to the exhaust port of an associated sample region. A light source, typically a laser, is positioned to project an incident beam along a light path which intersects each of the partial sample flows through the sample regions. Particles contained within the partial sample flows scatter light as the particles pass through the incident beam. The light from a sample region is directed to a photodetector which provides a signal corresponding to the sensed light. Particle detection in each sample region is operationally independent of the others, but the information is combined to provide a total particle count of the aggregate sample flow. Alternatively, the apparatus may be utilized to provide simultaneous particle detection of separate sources of particle-bearing gas. For example, adjacent clean room areas may be monitored channelling separate sample flows directly into separate inlet ports of adjacent sample regions.

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Grants Pass, OR, United States of America

Louis J Petralli