Device and method to locate, detect, and remove precipitated aerosol particles

Abstract

A method and apparatus are described by which previously identified aerosol particles that may have precipitated onto surfaces and/or into specific physical regions are detected, removed from said regions, and stored for later examination or destruction. The method includes means such as an ultrasonic probe to loosen said aerosol particles from the surfaces to which they have precipitated and then withdraw them into an optical read head for measurement. The optical read head illuminates each particle, previously diluted and entrained in a sheath flow, as it passes therethrough with a fine beam of light such as produced by a laser. The scattered light produced by each such particle is collected over a range of scattering angles, converted into a digital representation for each value collected, and stored in a computer means. The collected scattered light signals from each particle are then processed to compute a set of identification values, called optical observables or OOs, for subsequent comparison with a previously stored set. The latter set corresponds to the OOs of a specific particle class sought. Once a match between the OO set of a particle detected and that of a particle sought is obtained, the apparatus provides alarm and collection means by which such particles may be stored for subsequent removal and examination and/or destruction.