Malvern Instruments Limited

Duncan Edward Stephenson

Clive Patrick Ashley Catterall

David John Watson

David Michael Spriggs

Apparatus () for measuring particle size distribution by light scattering comprises a blue LED () and a 633 nm helium neon laser (). Light output from the LED and laser is separately passed or reflected by a dichroic element () onto a common path through a sample cell () containing a sample, the particle size distribution of which is to be measured. Light scattered from the sample cell is detected by one or more detectors (B-H). Light transmitted by the sample cell is detected by detectorsA,J. Output signals from one or more of the detectors are passed to a computation unit () which calculates particle size distribution. A small percentage of light from the blue LED is reflected by the dichroic element to a detector (). Similarly, a small percentage of light from the laser is passed by the dichroic element to the detector. Output signals from the detector are fed back to control units () to stabilize the output power of the LED and laser.

Apparatus and method for measuring particle size distribution by light scattering

A particle suspension handling system comprises a dispersion unit, a transport element, a cell and an outlet region. The dispersion unit has a transducer externally thereof, which is arranged, in use, to transfer energy into the suspension. The transport element is located within the dispersion unit. The transport element is arranged, in use, to recirculate the suspension about a flow path including the dispersion unit and the cell. The outlet region includes first and second valve members. The valve members can be arranged in a first configuration wherein they are spaced apart such that the space between them defines a discharge opening via which a fluid or the suspension exits the system, in use. The valve members can also be arranged in a second configuration wherein they abut and a flow path of substantially constant cross-section is provided about the outlet region.

Sample handling system

A particle size distribution analysis apparatus comprising a sample measurement zone adapted to define a sample of particles, a light emitting means adapted to provide a source of light incident upon the sample measurement zone, and at least a first detection means adapted to measure light levels in the apparatus at particular scattering angles and output a signal to a computation means enabling the particle size distribution of particles contained within the sample to be determined, wherein the computation means is adapted, in use, to calculate a particle size distribution taking into account reflections by the measurement zone of light scattered off the particles.

Measurement of particle size distribution

A particle size distribution analysis apparatus wherein there are provided a sample measurement zone adapted to contain a sample of particles, a light emitting means adapted to provide a source of light incident upon the measurement zone, and a detection means adapted to measure light levels at different scattering angles and to output signals to a computation means, enabling the size of particles contained within the sample to be determined, wherein the light emitting means comprises a first light source emitting a substantially monochromatic first wavelength of light and a second light source emitting a substantially monochromatic second, different, wavelength of light.

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Worcestershire, United Kingdom

Duncan Edward Stephenson