Wide-range particle counter
AssigneeMSP Corporation
InventorBenjamin Y. H. Liu
Life of this patent
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Abstract
A wide range particle counter has sections which separately detect coarse and fine particles in an aerosol. The coarse particles are counted and sized in an optical particle counter. The fine particles are classified with a differential mobility analyzer to determine size and then passed through a vaporizer and condenser and also counted. Using the different sections permits counting and measuring a wide range of particle size in a single instrument with high accuracy and reliability.
Claims37
Apparatus for detecting particles in a gas over a wide particle size range, said wide particle size range having an upper limit and a lower limit, and an intermediate particle size between the limits, said apparatus including a coarse-particle detector detecting particles in a coarse particle range between the upper limit and the intermediate particle size, a fine-particle detector detecting particles in a fine-particle range between the intermediate particle size and the lower limit, and signal processing means to process electrical signals from said particle detectors, said particle detectors and signal processing means being mounted on a common chassis.
An apparatus for measuring polydisperse particles over a wide size range in an aerosol flow including:
- a first optical detector receiving a first portion of the aerosol flow and detecting particles in the first portion of the aerosol flow and producing an output indicative of particle size in the first portion;
- a classifier receiving at least a second separate portion of the aerosol flow and producing an output modified aerosol flow having particles of substantially uniform electrical mobility;
- a condenser receiving the output modified aerosol flow and a working fluid and condensing vapor of the working fluid on particles classified by the classifier to form droplets in the modified aerosol flow;
- and
- a second optical detector receiving and detecting droplets in the modified aerosol flow from the condenser.
An apparatus for detecting particles in a gas including a chassis, a coarse-particle detector, a fine-particle detector, and signal processing means for processing electrical signals from the detectors, said particle detectors and signal processing means being mounted on the same chassis;
- and means on the mounted chassis for maintaining gas flows through the coarse and fine-particle detectors, so that the volumetric rate of gas flow through the coarse-particle detector is at least as large as the volumetric rate of gas flow through the fine-particle detector.
Dependencies are inferred from the claim text.