초록 ▼

A detection device is disclosed for determining particle size from particle effected light scattering in a sensing region illuminated by a laser beam and receiving the particles in a medium, such as air. Background light from molecular scattering is reduced to a level that enables light scattered by

A detection device is disclosed for determining particle size from particle effected light scattering in a sensing region illuminated by a laser beam and receiving the particles in a medium, such as air. Background light from molecular scattering is reduced to a level that enables light scattered by particles having a size of at least as low as about 0.1 micron to be sensed in a high background of molecular scattering such as, for example, where molecular scattering can exceed the 0.1 micron particle\s scattering by one hundred times. High sensitivity at high molecular scattering background is achieved through use of a linear array of detectors positioned, with respect to an imaging system, so that each detector monitors a different portion of the sensing region and provides an electrical output signal indicative of sensed particle presence within that portion monitored, with the output signals from the detectors being parallel processed and with the output signals from detectors monitoring non-adjacent portions of the sensing region being combined at noise cancellation units.

대표청구항 ▼

In a particle size detection device having first means for enabling a medium having particles therein to be passed through a predetermined sensing region and second means for illuminating said sensing region so that particles in said sensing region cause light scattering, an improved particle sensin

In a particle size detection device having first means for enabling a medium having particles therein to be passed through a predetermined sensing region and second means for illuminating said sensing region so that particles in said sensing region cause light scattering, an improved particle sensing system comprising: detecting means for receiving and detecting light scattered at said sensing region, said detecting means including a plurality of detectors positioned so that predetermined ones of said detectors receive light scattered from predetermined portions of said sensing region, with said predetermined portions of said sensing region being spaced with respect to one another, and with each of said detectors providing an output that can include both noise and signals indicative of sensed light scattered by particles within said predetermined portion of said sensing region monitored by that detector; and processing means including noise cancellation means connected with said predetermined ones of said detectors, said noise cancellation means causing noise included in said outputs from said predetermined ones of said detectors to be substantially cancelled so that the output from said processing means is effectively indicative of said particles causing said light scattering in said sensing region.