Particle detection system utilizing an inviscid flow-producing nozzle

摘要

A particle detection system in which a beam of light is incident upon an inviscid jet of fluid. A sample fluid containing particles is passed through an inviscid flow producing nozzle. An inviscid flow jet is output from the nozzle. The entire inviscid flow jet moves with uniform velocity and can therefore be contained within the sample region for the detection system. A volumetric measurement is thereby achieved where all of the sample fluid moves with uniform velocity. Sample fluid is decelerated in a deceleration chamber to a velocity significantly less than the nozzle velocity. The nozzle has a length and a width where the ratio of length to width is less than about 1. Sample fluid flows from the deceleration chamber through the nozzle and is output from the nozzle in an inviscid flow jet into a collection chamber. An optical collector system collects light scattered by particles in the inviscid flow jet and images the scattered light on a detector. The shape of the inviscid flow jet can be circular or non circular. An inviscid flow jet having a high aspect ratio can be fully illuminated by a relatively focussed beam of light providing a highly sensitive measurement.