LIQUIDBORNE PARTICLE SENSING METHOD USING AEROSOLIZING TECHNIQUES

摘要

1335735 Counting particles COULTER ELECTRONICS Inc 29 Jan 1971 3498/71 Heading G4D [Also in Division G1] Small particles in a liquid sample are counted by making an aerosol of the sample with warm dry air and passing this through an optical particle sensor to determine particle size and number concentration. The optical sensor comprises light source 12, lens 13, aperture 14, projection lens 16, flow tube 17 and photomultiplier 18 and operates by detection of light scattered from the particles. Production of aerosol.-Clean, dry air is supplied to the aerosol producing arrangement of Fig. 2, by the apparatus shown in Fig. 1. Pump 33 feeds air through drier 37 and two supplies are provided via valve 36 and filter 38, and valve 41 and filter 42, respectively. The first supply is used to form a jet of air at nozzle 27 of tube 26, by which the aerosol is formed, the sample carried in pipette 52. The second supply passes via tube 29 and holes 28 to shield the aerosol particles from the internal walls of tube 21. The flow through holes 28 may alternatively be produced using air supplied through hole and filter 31. Alternatively to this air-jet method, an ultrasonic technique may be used to generate an aerosol of the sample. Different ultrasonic frequencies may be used to drive different sizes of particles selectively.