Method of performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample by laser and apparatus therefor

An apparatus for performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample having a surface which moves in the vertical direction, comprising:

• a laser oscillating means for generating a high output pulse laser;
• a focusing lens, which is provided at a fixed position a varying distance L from the vertically moving surface of the flowing fluid sample of the substance to be measured, such that the relationship between L and the focal length f of said lens constantly satisifies the formula:
• 0.95f.ltoreq.L.ltoreq.1.05f,
• wherein the focal length f is at least ten times as large as the range of vertical movement of the surface of said substance to be measured, for focusing the laser generated by said laser oscillating means onto the surface of said flowing fluid sample of the substance to be measured;
• and
• spectral separating means for analyzing spectroscopically the light emitted from the surface of said substance to be measured.

An apparatus for performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample which includes a vertically moving surface, comprising:

• a laser oscillating means for generating a high output pulse laser;
• a focusing lens, which has a focal length f and is provided at a fixed position spaced a varying distance L from the vertically moving surface of the flowing fluid sample of the substance to be measured for focusing the laser generated by said laser ocsillatng means onto a surface of the substance to be measured;
• and
• means for controlling the distance L such that the relationship between L and f can constantly satisfy the formula:
• 0.95f.ltoreq.L.ltoreq.1.05f;
• and
• spectral separating means for analyzing spectroscopically the light emitted from the surface of said substance to be measured.