Abstract: An optical particle counter determines the velocity of particles passing through a particle detection zone, and thereby the velocity of gas flow, from both the measured time of flight of discrete particles and also the size of intensity peaks of scattered light. This is used to determine particle concentration and may be used to control an optional fan.

Abstract: A method for determining the presence of crystalline silica particles in a sample comprising a plurality of particles. The method comprises: receiving first data generated based upon light scattered by at least one particle of said plurality of particles; receiving second data generated based upon intensity and polarization change of the light transmitted through at least one particle of said plurality of particles; and determining the presence of crystalline silica particles in the sample based upon the first data and second data.

Abstract: A method for determining the presence of crystalline silica particles in a sample comprising a plurality of particles. The method comprises: receiving first data generated based upon light scattered by at least one particle of said plurality of particles; receiving second data generated based upon intensity and polarisation change of the light transmitted through at least one particle of said plurality of particles; and determining the presence of crystalline silica particles in the sample based upon the first data and second data.

Abstract: An optical particle counter determines the velocity of particles passing through a particle detection zone, and thereby the velocity of gas flow, from both the measured time of flight of discrete particles and also the size of intensity peaks of scattered light. This is used to determine particle concentration and may be used to control an optional fan.

Abstract: An apparatus for the detection of a fluid-borne particle (10) in an optically defined particle sensing zone, the apparatus comprising: i) a scattering chamber (40); ii) a means for providing a sample of fluid (34), containing the fluid-borne particle, in the form of a flow through the optically defined particle sensing zone; iii) A means for generating a beam of radiation (12) through the optically defined particle sensing zone; iv) a single reflector or refractor (14) means having a primary focus (16) within the optically defined particle sensing zone and a secondary focus (20) located outside the beam of radiation; v) a detector means comprising a first photosensitive detection area (26) a second photosensitive detection area (29); vi) a means for deriving area from the radiation detected by the first photosensitive detection area and second photosensitive detection area of the detection means wherein the single reflector or refractor means is adapted to direct radiation scattered from the fluid borne parti

Abstract: There is disclosed improved apparatus and methods for detection of shape, size and intrinsic fluorescence properties of a fluid borne particle wherein the apparatus comprises a laser, two light sources, two detectors, and optionally a third detector. The apparatus is particularly suitable for detection of airborne biological particles.

Abstract: There is disclosed improved apparatus and methods for detection of shape, size and intrinsic fluorescence properties of a fluid borne particle wherein the apparatus comprises a laser, two light sources, two detectors, and optionally a third detector. The apparatus is particularly suitable for detection of airborne biological particles.

Abstract: There is disclosed improved apparatus and methods for detection of shape, size and intrinsic fluorescence properties of a fluid borne particle wherein the apparatus comprises a laser, two light sources, two detectors, and optionally a third detector. The apparatus is particularly suitable for detection of airborne biological particles.

Abstract: An apparatus for the detection of a fluid-borne particle (10) in an optically defined particle sensing zone, the apparatus comprising: i) a scattering chamber (40); ii) a means for providing a sample of fluid (34), containing the fluid-borne particle, in the form of a flow through the optically defined particle sensing zone; iii) A means for generating a beam of radiation (12) through the optically defined particle sensing zone; iv) a single reflector or refractor (14) means having a primary focus (16) within the optically defined particle sensing zone and a secondary focus (20) located outside the beam of radiation; v) a detector means comprising a first photosensitive detection area (26) a second photosensitive detection area (29); vi) a means for deriving area from the radiation detected by the first photosensitive detection area and second photosensitive detection area of the detection means wherein the single reflector or refractor means is adapted to direct radiation scattered from the fluid borne parti

Abstract: There is disclosed improved apparatus and methods for detection of shape, size and intrinsic fluorescence properties of a fluid borne particle wherein the apparatus comprises a laser, two light sources, two detectors, and optionally a third detector. The apparatus is particularly suitable for detection of airbone biological particles.

Abstract: This invention describes an improved method and apparatus for the analysis of fluid borne particles and which is especially suitable for the detection of airborne biological particles. In one aspect of the invention provides an apparatus for the detection of fluid borne particles which comprises a zone through which a fluid to be analyzed flows in use, a source of illumination to illuminate/irradiate fluid borne particles present in said zone, and a detector to detect light from the particles as an indicator of the presence or characteristics of the particles, wherein the apparatus comprises an integrating sphere and the zone is within the integrating sphere. The apparatus is highly sensitive and can be used for detecting airborne particles even where the particles are present at very low particle concentrations in the air.

Abstract: A fibre detector assembly comprising: (i) a scattering chamber body; (ii) means for drawing airborne particles through said body chamber, said means being adapted such the the particles tend to travel in single file with the longitudinal axis of particles with elongate shape substantially aligned with the direction of the air flow; (iii) means for illuminating the particle stream within the chamber body; (iv) an optical detector adapted to intercept and collect a portion of the light scattered by particles passing through the illuminating beam; (v) data processing means adapted to capture and process the signals from the optical detector; characterised in that the optical detector comprises a photodiode array consisting of a central opaque area surrounded by two or more annular rings of detector elements.