Method and apparatus for in-process liquid analysis by laser induced plasma spectroscopy

A laser-induced plasma spectroscopy apparatus for the analysis of the composition of liquid and molten materials comprising:

• a laser emitting pulses at given repetition rate and along a given beam path;
• an optical means to direct the laser pulses to a location at a surface of the liquid to generate a plasma that emits elemental radiation that corresponds to at least one compositional element of the liquid;
• a probe structure, which detects the emitted elemental radiation along a detection path, said probe structure including an optical window, a spectrometer for analyzing the spectra of the emitted radiation, a detector to detect the light diffracted by the spectrometer, a data processor which determines a concentration of the predetermined element;
• a gas flow generator to substantially prevent liquid drops, which are ejected from the liquid in response to the incident laser pulses, from accumulating on said optical window of said probe structure and along the laser beam path and the detection path;
• and
• a flow cell assembly which establishes a substantially steady flow of the liquid past the said location at the surface of the liquid, the flowing liquid at this location being truly representative of the liquid bulk flown into the cell, said cell assembly including a controller to control the liquid surface level and the flow speed.