Patent ID: 9116121
Filing Date: 2015-08-25
Classification: G01N

Abstract:
1. An apparatus for the detection of a fluid-borne particle in an optically defined particle sensing zone, the apparatus comprising: i) a scattering chamber configured to receive a sample of fluid, containing the fluid-borne particle, in the form of a flow through the optically defined particle sensing zone; ii) a diode laser for generating a beam of radiation through the optically defined particle sensing zone; iii) a single reflector or refractor having a primary focus within the optically defined particle sensing zone and a secondary focus located outside the beam of radiation; and iv) a single scattered light detector comprising a first photosensitive detection area and a second photosensitive detection area, wherein the first photosensitive detection area and the second photosensitive detection area are integral and the first photosensitive detection area is located wholly within the second photosensitive detection area, and wherein the scattered light detector is configured to generate electrical signals representative of the radiation detected by the first photosensitive detection area and second photosensitive detection area, wherein the single reflector or refractor is adapted to direct radiation scattered from the fluid borne particle passing through the beam of radiation within the optically defined particle sensing zone to the scattered light detector located at a secondary focus of the single reflector or refractor, wherein the optically defined sensing zone compromises a first zone defined by radiation detected by the first photosensitive detection area of the scattered light detector and a second zone defined by radiation detected by the second photosensitive detection area of the scattered light detector, wherein the first zone is smaller than the second zone, and wherein the first zone is located wholly inside the second zone.