CA1225844A - Method of continuously analyzing fluidized body by laser and apparatus therefor - Google Patents
Method of continuously analyzing fluidized body by laser and apparatus thereforInfo
- Publication number
- CA1225844A CA1225844A CA000469782A CA469782A CA1225844A CA 1225844 A CA1225844 A CA 1225844A CA 000469782 A CA000469782 A CA 000469782A CA 469782 A CA469782 A CA 469782A CA 1225844 A CA1225844 A CA 1225844A
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- substance
- measured
- laser
- flowing fluid
- fluid sample
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Abstract
ABSTRACT OF THE DISCLOSURE
A focusing lens having a focal length f is provided at a position spaced a distance L apart from a substance to be measured in the fluidized conditions, control is effected such that the relationship between L and f constanly satisfied a formula 0.95f ? L ? 1.05f, and a light emitted by high output pulse laser irradiating the surface of the substance to be measured is spectroscopically analyzed, so that the influence of variations on the surface of the substance to be measured can be avoided and stabilized laser emission spectroscopically analysis on line can be conducted.
A focusing lens having a focal length f is provided at a position spaced a distance L apart from a substance to be measured in the fluidized conditions, control is effected such that the relationship between L and f constanly satisfied a formula 0.95f ? L ? 1.05f, and a light emitted by high output pulse laser irradiating the surface of the substance to be measured is spectroscopically analyzed, so that the influence of variations on the surface of the substance to be measured can be avoided and stabilized laser emission spectroscopically analysis on line can be conducted.
Description
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METHOD OF CONTINIOUSLY ANALYZING FLUIDIZED BODY BY LASER
AND APPARATUS THEREFOR
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to a method of continuously on-line analyzing by laser a multiple constituent elements of a metal or an insulating material such as a hot metal, molten steel, slag, glass and semiconductor in various fluidized conditions without being in contat therewith, and an apparatus therefor.
METHOD OF CONTINIOUSLY ANALYZING FLUIDIZED BODY BY LASER
AND APPARATUS THEREFOR
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to a method of continuously on-line analyzing by laser a multiple constituent elements of a metal or an insulating material such as a hot metal, molten steel, slag, glass and semiconductor in various fluidized conditions without being in contat therewith, and an apparatus therefor.
2. Description of ~he Prior Art For analyzing a molten substance, there has heretofore been adopted any one of the following methods or a combination therebetween.
(1) To analyze a sample left at rest in a closed vessel such as a crucible.
(2) To analyze the sample collected from a flow of a molten substance.
(1) To analyze a sample left at rest in a closed vessel such as a crucible.
(2) To analyze the sample collected from a flow of a molten substance.
(3) To analyze the flow of the molten substance by immersing a portion of an excitation source or of a measuring system in the flow.
However, it is difficult for the method of analyzing the sample left at rest in the closed vessel to directly adopt in an analysis during a manufacturing process.
Furthermore, the methods of collecting the sample from the flow and immersing the analytical equipment in the flow of the molten substance have been disadvantageous in that the ;,. . .:
"' '`
flow of the substance to be measured i5 disturbed and conta~inated.
SUMMARY OF THE I~VENTION
The present invention has been developed to obviate the above-described disadvantages of the prior art and contemplates that an on-line analysis of the constituents of a metal or an insulating substance being in the fluidized conditions is to be conducted without being in contact therewith. An object of the present invention is to conduct a continuous on-line analysis of constituents of a substance to be measured, with an excitation source and a measuring system not being in contact with the substance by a method wherein the molten substance to be measured in the fluidized conditions is irradiated by a high output pulse laser beam and an emission spectrum obtained then is spectrally separated.
There have been several cases where this laser emission analysis is applied to the molten substances. However, all of these cases presuppose the sample left at rest in a closed vessel such as a crucible, but do not relate to the on-line analysis during a manufacturing process where a molten substance is in the fluidized conditions and the surface thereof is moved in the vertical direction.
The present invention relates to an on-line analysis in the manufacturing process where the substance to be measured continuously flows in the molten conditions, and is based on a basic method of a laser emission spectroscopical analysis.
According to the laser emission spectroscopical analysis, a :
i8~
powerful pulse-shaped laser beam is focused onto the surface of the substance to be measured to cause a surface layer of the substance to be measured to evaporate at a moment, a light is generated from the substance by the excitation of the laser beam, and the light generated is spectrally separat-ed, to thereby conduct an analysis of the constituents. In consequence, there is no need to bring the substance to be measured in contact with a laser system and a spectroscope system.
Now, in practically applying this method of analysis to an analysis on the site, the influence of the vertical movement of the substance to be measured constitutes a major problem. To study the effects of vertical movement of the substance to be measured, the inventors of the present inven-tion use an apparatus which comprises an infrared pulse laser having a pulse width of 15 nanosecond, an output of 2 joule and a wavelength of 1.06 micrometer was used.
The invention therefore provides a method of per-forming continuous on-line laser emission spectroscopic analysis on a flowing fluid sample, which includes a vertically moving surface, comprising the steps of:
a) providing a focusing lens having a focal length f at a fixed position spaced a varying distance L from the ~5 vertically moving surface of the flowing fluid sample of the substance to ~e measured;
b) controlling the relationship between L and f such that the formula:
0,95f _ L _ 1.05f is constantly satisfied; and c) spectroscopically analyzing the light emitted by said substance to be measured when said substance is irra-diated by a high power pulse laser.
;
, ~; `~ ; `~'' :
:
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The invention also provides an apparatus for per-forming continuous on-line laser emission spectroscopic analysis on a flowing fluid sample having a surface which moves in the vertical direction, comprising:
a) a laser oscillating means for generating a high output pulse laser;
b) 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 satisfies the formula:
0.95f _ L < l.OSf, wherein the focal length f is at least ten times as large as the range of vertical movement of the surface of said subs-tance 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 c) spectral separating means for analyzing spectro-scopically the light emitted from the surface of said subs-tance to be measured.
The invention further provides an apparatus for performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample which includes a vertically moving surface, comprising:
a) a laser oscillating means for generating a high output pulse laser;
b) 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 sam-ple of the substance to be measured for focusing the laser generated by said laser oscillating means onto a surface of the substance to be measured;
- 3a -.
...
, ~L~2~
c) means for controlling the distance L such ~hat the relationship between L and f can constantly satisty the formula:
0.95f _ L _ 1.05f; and d) spectral separating means for analyzing spectros-copically the light emitted from the surface of said substance to be measured.
`DETAILED DESCRIP~ION OF THE INVENTION
The exact nature of this invention, as well as other objects and advantages thereof, will be readily apparent from consideration of the following specification relating to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof and wherein:
Fig. 1 is a schematic side view showing the appara-tus for laser spectroscopical analysis, which was used tostudy the effect of vertical movement of the surface of the substance to be measured7 Fig. 2 is a graphic chart showing the changes in the intensities of spectra due to vertical movements on the sur-face of Fe-0.3% Mn;
Fig. 3 is a graphic chart showing the range where the intensity ratio of spectra becomes constant;
Fig. 4 is a graphic chart showing the changes in the intensities of spectra due to the vertical movements of the surface of SiO2-Al~O3; and Fig. 5 is a side view showing an apparatus embodying the present invention on an iron runner.
Description will now be given of Fig. 1. A laser beam generated by a laser oscillator 1 is diverted downwardly - 3b -~" ~
,:
: :
- .
~2~
by a prism 2, and focused by focussing lens 3 onto the sur-face of a substance 4 to be measured. Here, the substance
However, it is difficult for the method of analyzing the sample left at rest in the closed vessel to directly adopt in an analysis during a manufacturing process.
Furthermore, the methods of collecting the sample from the flow and immersing the analytical equipment in the flow of the molten substance have been disadvantageous in that the ;,. . .:
"' '`
flow of the substance to be measured i5 disturbed and conta~inated.
SUMMARY OF THE I~VENTION
The present invention has been developed to obviate the above-described disadvantages of the prior art and contemplates that an on-line analysis of the constituents of a metal or an insulating substance being in the fluidized conditions is to be conducted without being in contact therewith. An object of the present invention is to conduct a continuous on-line analysis of constituents of a substance to be measured, with an excitation source and a measuring system not being in contact with the substance by a method wherein the molten substance to be measured in the fluidized conditions is irradiated by a high output pulse laser beam and an emission spectrum obtained then is spectrally separated.
There have been several cases where this laser emission analysis is applied to the molten substances. However, all of these cases presuppose the sample left at rest in a closed vessel such as a crucible, but do not relate to the on-line analysis during a manufacturing process where a molten substance is in the fluidized conditions and the surface thereof is moved in the vertical direction.
The present invention relates to an on-line analysis in the manufacturing process where the substance to be measured continuously flows in the molten conditions, and is based on a basic method of a laser emission spectroscopical analysis.
According to the laser emission spectroscopical analysis, a :
i8~
powerful pulse-shaped laser beam is focused onto the surface of the substance to be measured to cause a surface layer of the substance to be measured to evaporate at a moment, a light is generated from the substance by the excitation of the laser beam, and the light generated is spectrally separat-ed, to thereby conduct an analysis of the constituents. In consequence, there is no need to bring the substance to be measured in contact with a laser system and a spectroscope system.
Now, in practically applying this method of analysis to an analysis on the site, the influence of the vertical movement of the substance to be measured constitutes a major problem. To study the effects of vertical movement of the substance to be measured, the inventors of the present inven-tion use an apparatus which comprises an infrared pulse laser having a pulse width of 15 nanosecond, an output of 2 joule and a wavelength of 1.06 micrometer was used.
The invention therefore provides a method of per-forming continuous on-line laser emission spectroscopic analysis on a flowing fluid sample, which includes a vertically moving surface, comprising the steps of:
a) providing a focusing lens having a focal length f at a fixed position spaced a varying distance L from the ~5 vertically moving surface of the flowing fluid sample of the substance to ~e measured;
b) controlling the relationship between L and f such that the formula:
0,95f _ L _ 1.05f is constantly satisfied; and c) spectroscopically analyzing the light emitted by said substance to be measured when said substance is irra-diated by a high power pulse laser.
;
, ~; `~ ; `~'' :
:
' s~
The invention also provides an apparatus for per-forming continuous on-line laser emission spectroscopic analysis on a flowing fluid sample having a surface which moves in the vertical direction, comprising:
a) a laser oscillating means for generating a high output pulse laser;
b) 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 satisfies the formula:
0.95f _ L < l.OSf, wherein the focal length f is at least ten times as large as the range of vertical movement of the surface of said subs-tance 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 c) spectral separating means for analyzing spectro-scopically the light emitted from the surface of said subs-tance to be measured.
The invention further provides an apparatus for performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample which includes a vertically moving surface, comprising:
a) a laser oscillating means for generating a high output pulse laser;
b) 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 sam-ple of the substance to be measured for focusing the laser generated by said laser oscillating means onto a surface of the substance to be measured;
- 3a -.
...
, ~L~2~
c) means for controlling the distance L such ~hat the relationship between L and f can constantly satisty the formula:
0.95f _ L _ 1.05f; and d) spectral separating means for analyzing spectros-copically the light emitted from the surface of said substance to be measured.
`DETAILED DESCRIP~ION OF THE INVENTION
The exact nature of this invention, as well as other objects and advantages thereof, will be readily apparent from consideration of the following specification relating to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof and wherein:
Fig. 1 is a schematic side view showing the appara-tus for laser spectroscopical analysis, which was used tostudy the effect of vertical movement of the surface of the substance to be measured7 Fig. 2 is a graphic chart showing the changes in the intensities of spectra due to vertical movements on the sur-face of Fe-0.3% Mn;
Fig. 3 is a graphic chart showing the range where the intensity ratio of spectra becomes constant;
Fig. 4 is a graphic chart showing the changes in the intensities of spectra due to the vertical movements of the surface of SiO2-Al~O3; and Fig. 5 is a side view showing an apparatus embodying the present invention on an iron runner.
Description will now be given of Fig. 1. A laser beam generated by a laser oscillator 1 is diverted downwardly - 3b -~" ~
,:
: :
- .
~2~
by a prism 2, and focused by focussing lens 3 onto the sur-face of a substance 4 to be measured. Here, the substance
4 to be measured is an Fe-0.3~ Mn alloy which was melted in a Tanmann-furnace 5. At this time, to suppress production of an oxide layer on the surface of the substance 4 to be measured, argon gas is blown in through an argon gas introduction por-tion 6 and released through an argon gas discharge portion 7 to the outslde of the system, as a r .
C . . . ~
- 3c -.
, ' generation of the oxide layer was suppressed. A light generated by the laser beam is introduced to a spectroscope 10 by a light introduction system constituted by a concave mirror 8, plane mirrors 9a and 9b. In the spectroscope 10, the wavelength separation is conducted by an ordinary method, and intensities of 271.4 nanometer wavelength Fe spectrum and 293.3 nanometer wavelength Mn spectrum were measured by two light detectors 11.
To change the distance between the substance 4 to be measured and the laser spectroscope optical system, the Tanmann-furnace 5 was mounted on a lift 12 and the melting furnace as a whole was moved in t~e vertical direction. In this case, to avoid disturbing the flow of argon gas, a fitting 13 is interposed between the light introducing system and the Tanmann-furnace 5.
As the focusing lenses 3, focusing lenses of five types having the focal lengths of 20, 50, 100, 150 and 200 centimeter, respectively, were used~ being exchanged from one to another.
When the focusing lenses 3 are exchanged, the radius of the concave mirror ~ was selected such tha' a light generated, when the surface of the substance to be measured was at its focus, formed its image at an inlet slit 14 of the spectroscope, and the plane mirrors 9a and 9b were adjusted in angle. Fig. 2 shows the intensities of Fe and Mn spectra by the vertical movement of the substance 4 to be measured and a change in the ratio therebetween when a focusing lens having a focal length of 100 centimeter is used. As the surface of the substance 4 to be measured is shifted from the focus of the focusing lens 3, the intensity of the spectrum is progressiYely decreased. ~owever, ~ . . . .
:
the intensity ratio between the spectra used in the analysis is not varied even if the surface of the substance is shifted from the focus of the focusing lens 3 by 5 centimeter in the vertical direction. The measurement similar to the above were conducted with the focusing lenses 3 being exchanged, and the results of the measurements are put together and shown in Fig. 3. If the relationship of a distance L between the focusing lens 3 and the surface of the substance 4 to be measured with a focal length f of the focusing lens 3 was given by the following formula, 0.95f c L ' 1.05f ------- (lj then, it was found that the intensity ratio between the spectra was constant and a stable analyzed value was obtainable in spite of the vertical movement of the substance to be measured.
Then, as the substance 4 to be measured, SiO2 - A12O3 as being the insulating substances were used, and the measurements similar to that shown in Fig. 2 were conducted on line spectra of Si (288.2 nanometer wavelength) and Al (309.3 nanometer wavelength). Fig. 4 shows the results. In this case also, even if the surface of the substance to be measured is shifted from the focus of the focusin~ lens 3 by 5 centimeter, the intensity ratio between the spectra is substantially constant. Further, the results of measurements conducted, with the focusing lenses 3 being exchanged from one to another, are substantially equal to that shown in Fig. 3, and it has been clarified that, only if the above-mentioned formula (1) is satisfied, the surface of the substance to be measured is not subjected to the influence of the vertical movement of the surface of the substance to be .
: :
.
' ~ , ~2~8~
measured.
The present invention is based on the above-described knowledge and the technical gist thereof resides in a method of continuously analyzing a fluidized body by laser and an apparatus therefor, wherein a focusing lens having a focal length f is provided at a position spaced a distance L apart from the surface of the substance to be measured in the fluidized conditions, control is effected such that the relationship between L and f can satisfy a fonmula 0.95f _ L ~ 1.05f, and an emission of a high power pulse laser, which has irradisted the surface of the substance to be measured, is spectroscopically analyzed.
According to the present invention, even in a manufacturing process where the substance to be measured continuously flows and the vertical movement of the surface of the substance is unavoidable, a laser spectroscope system is provided at a position where the above-mentioned formula (1) is satisfied and a focusing lens 3 having a suitable focal length is selected, so taht a stable laser emission spectroscopical analysis can be achieved. Use of focusing lenses having focal lengths 100 to 200 centimeter makes it possible to tolerate the vertical movement ranging from 10 to 20 centimeter of the surface of the substance to be measured. A portion of an ordinary manufacturing process, where the width of variations in the vertical direction is restricted to the above-mentioned range, may be found and the variations in the movement of the surface .
34~
of the substance to be measured may be controlled to within the above-mentioned range, so that the present invention can be easily worked. This control may be achieved by improving the manufacturing process, specially preparing a runner or the like for constantly satisfying the above-mentioned formula (1) and controlling the runner, or by controlling an inclination of the melting furnace, so that a flow of the substance to be measured, which flows out of the melting furnace, may satisfy the above-mentioned formula (1), for example.
In working the present invention, a variation range of the vertical movement of the surface of the substance to the measured at a position where the apparatus is installed is measured by a suitable method. If a focusing lens having a focal length as large as ten times or more the variation width at this time, then the formula (1) is constantly established and necessity of control of the distance between the substance to be measured and the focusing lens is eliminated. Furthermore, depending on the condition, there is adopted such a method that the variation range of the vertical movement of the surface of the substance to be measured may be one-tenth or less the focal length of the focusing lens.
Subsequently, the light introducing system i~ adjusted such that the light emitted from the surface of the substance to ~e measured forms an image at the inlet slit of the spectroscope~
As the laser, an infrared pulse laser is suitable, however, a ruby laser capable of obtaining a visible beam may be adopted.
Nell known methods are used to spectrally separate a light ~L~2~34~
emitted by the irradiation of laser and to measure the in-tensity of a specified spectrum.
When other materials such as an oxide layex or other obstacle are present on the surface of the substance to be measured, measures such as blo~ng argon gasornitrogen ~asonto the materials to remove the oxide layer o~ using an obstacle to separate the materials from the substance to be measured, are provided so that the laser beam can directly irradiate the substance to be measured.
According to the present invention, substances in a fluid state can be analyzed on-line with high accuracy by use of a laser and the accuracies in the process control and the quality control on line are improved to a considerable extent.
Detailed description will hereunder be given of the embodiment of the present invention with reference to the drawings.
Fig. 5 is a side view showing the apparatus embody-ing the present invention. The substance 4 to be measured is hot metal flowing through an iron through of a blast furnace.
Normally, slag is mounted on the surface of hot metal. The laser spectroscope is provided at a position, where the slag has been just removed by means of a skimmer. For the laser, an infrared ray pulse laser having a pulse width of 15 nano--second and an output of 2 joule was used. The laser oscilla-tor 1 and the spectroscope 10 are fixed onto an analytical bed 15. The laser beam is vertically diverted by the prism 2 in the direction of the substance to be measured and fo-cused by the focusing lens 3. The maximum vertical movement of the surface of hot metal at this analytical point is 10 centimeters. Accordingly, a focusing lens 3, having a focal length at least ten times or more the maximum "i~
.
:
~z~s~
vertical movement, i.e., 100 centimeter or more may be used.
However, a lens having a focal length of 170 centimeter was used so that the light introducing system and so on were not subjected to a radiant heat of the hot metal to an excessive extent. The light emitted by the irradiation of laser was adopted to form its image at the inlet slit 14 of the spectroscope by the li~ht introducing system constituted by the concave mirror 8, the plane mirrors 9a and 9b. To prevent this light introducing system from being contaminated by gases and dust, argon gas was blown in through the argon gas introduction portion 6. Further, to ensure the prevention of the contamination completely, an argon gunning pipe 16 was mounted to the lower portion of the light introducing system, and argon gas was further blown in through an additional argon gas blown in portion 17. The spectroscope 10 spectrally separated by use of a diffraction gratin~ of 2400 line/mm at a focal length of 200 centimeter and the spectrum intensity was detected by a photomultiplier tube 1~. Table 1 shows the elements analyzed, the wavelengths of spectra and the results of analysis. The results of conventional method, in which the samples were collected, left at rest in crucibles and analyzed, were additionally shown in this table. The results of analysis according to the present invention well coincide with those obtained by the conventional method.
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Table 1 Wavelength Results of analysis (%) Element nanometer Present method Conventional method Si 212.4 0.40 0.37 Mn 293.3 0.39 0.44 Cr 267.7 0.021 0.023 Ni 231.6 0.018 0.016 ~r -.....
:
.~
:
C . . . ~
- 3c -.
, ' generation of the oxide layer was suppressed. A light generated by the laser beam is introduced to a spectroscope 10 by a light introduction system constituted by a concave mirror 8, plane mirrors 9a and 9b. In the spectroscope 10, the wavelength separation is conducted by an ordinary method, and intensities of 271.4 nanometer wavelength Fe spectrum and 293.3 nanometer wavelength Mn spectrum were measured by two light detectors 11.
To change the distance between the substance 4 to be measured and the laser spectroscope optical system, the Tanmann-furnace 5 was mounted on a lift 12 and the melting furnace as a whole was moved in t~e vertical direction. In this case, to avoid disturbing the flow of argon gas, a fitting 13 is interposed between the light introducing system and the Tanmann-furnace 5.
As the focusing lenses 3, focusing lenses of five types having the focal lengths of 20, 50, 100, 150 and 200 centimeter, respectively, were used~ being exchanged from one to another.
When the focusing lenses 3 are exchanged, the radius of the concave mirror ~ was selected such tha' a light generated, when the surface of the substance to be measured was at its focus, formed its image at an inlet slit 14 of the spectroscope, and the plane mirrors 9a and 9b were adjusted in angle. Fig. 2 shows the intensities of Fe and Mn spectra by the vertical movement of the substance 4 to be measured and a change in the ratio therebetween when a focusing lens having a focal length of 100 centimeter is used. As the surface of the substance 4 to be measured is shifted from the focus of the focusing lens 3, the intensity of the spectrum is progressiYely decreased. ~owever, ~ . . . .
:
the intensity ratio between the spectra used in the analysis is not varied even if the surface of the substance is shifted from the focus of the focusing lens 3 by 5 centimeter in the vertical direction. The measurement similar to the above were conducted with the focusing lenses 3 being exchanged, and the results of the measurements are put together and shown in Fig. 3. If the relationship of a distance L between the focusing lens 3 and the surface of the substance 4 to be measured with a focal length f of the focusing lens 3 was given by the following formula, 0.95f c L ' 1.05f ------- (lj then, it was found that the intensity ratio between the spectra was constant and a stable analyzed value was obtainable in spite of the vertical movement of the substance to be measured.
Then, as the substance 4 to be measured, SiO2 - A12O3 as being the insulating substances were used, and the measurements similar to that shown in Fig. 2 were conducted on line spectra of Si (288.2 nanometer wavelength) and Al (309.3 nanometer wavelength). Fig. 4 shows the results. In this case also, even if the surface of the substance to be measured is shifted from the focus of the focusin~ lens 3 by 5 centimeter, the intensity ratio between the spectra is substantially constant. Further, the results of measurements conducted, with the focusing lenses 3 being exchanged from one to another, are substantially equal to that shown in Fig. 3, and it has been clarified that, only if the above-mentioned formula (1) is satisfied, the surface of the substance to be measured is not subjected to the influence of the vertical movement of the surface of the substance to be .
: :
.
' ~ , ~2~8~
measured.
The present invention is based on the above-described knowledge and the technical gist thereof resides in a method of continuously analyzing a fluidized body by laser and an apparatus therefor, wherein a focusing lens having a focal length f is provided at a position spaced a distance L apart from the surface of the substance to be measured in the fluidized conditions, control is effected such that the relationship between L and f can satisfy a fonmula 0.95f _ L ~ 1.05f, and an emission of a high power pulse laser, which has irradisted the surface of the substance to be measured, is spectroscopically analyzed.
According to the present invention, even in a manufacturing process where the substance to be measured continuously flows and the vertical movement of the surface of the substance is unavoidable, a laser spectroscope system is provided at a position where the above-mentioned formula (1) is satisfied and a focusing lens 3 having a suitable focal length is selected, so taht a stable laser emission spectroscopical analysis can be achieved. Use of focusing lenses having focal lengths 100 to 200 centimeter makes it possible to tolerate the vertical movement ranging from 10 to 20 centimeter of the surface of the substance to be measured. A portion of an ordinary manufacturing process, where the width of variations in the vertical direction is restricted to the above-mentioned range, may be found and the variations in the movement of the surface .
34~
of the substance to be measured may be controlled to within the above-mentioned range, so that the present invention can be easily worked. This control may be achieved by improving the manufacturing process, specially preparing a runner or the like for constantly satisfying the above-mentioned formula (1) and controlling the runner, or by controlling an inclination of the melting furnace, so that a flow of the substance to be measured, which flows out of the melting furnace, may satisfy the above-mentioned formula (1), for example.
In working the present invention, a variation range of the vertical movement of the surface of the substance to the measured at a position where the apparatus is installed is measured by a suitable method. If a focusing lens having a focal length as large as ten times or more the variation width at this time, then the formula (1) is constantly established and necessity of control of the distance between the substance to be measured and the focusing lens is eliminated. Furthermore, depending on the condition, there is adopted such a method that the variation range of the vertical movement of the surface of the substance to be measured may be one-tenth or less the focal length of the focusing lens.
Subsequently, the light introducing system i~ adjusted such that the light emitted from the surface of the substance to ~e measured forms an image at the inlet slit of the spectroscope~
As the laser, an infrared pulse laser is suitable, however, a ruby laser capable of obtaining a visible beam may be adopted.
Nell known methods are used to spectrally separate a light ~L~2~34~
emitted by the irradiation of laser and to measure the in-tensity of a specified spectrum.
When other materials such as an oxide layex or other obstacle are present on the surface of the substance to be measured, measures such as blo~ng argon gasornitrogen ~asonto the materials to remove the oxide layer o~ using an obstacle to separate the materials from the substance to be measured, are provided so that the laser beam can directly irradiate the substance to be measured.
According to the present invention, substances in a fluid state can be analyzed on-line with high accuracy by use of a laser and the accuracies in the process control and the quality control on line are improved to a considerable extent.
Detailed description will hereunder be given of the embodiment of the present invention with reference to the drawings.
Fig. 5 is a side view showing the apparatus embody-ing the present invention. The substance 4 to be measured is hot metal flowing through an iron through of a blast furnace.
Normally, slag is mounted on the surface of hot metal. The laser spectroscope is provided at a position, where the slag has been just removed by means of a skimmer. For the laser, an infrared ray pulse laser having a pulse width of 15 nano--second and an output of 2 joule was used. The laser oscilla-tor 1 and the spectroscope 10 are fixed onto an analytical bed 15. The laser beam is vertically diverted by the prism 2 in the direction of the substance to be measured and fo-cused by the focusing lens 3. The maximum vertical movement of the surface of hot metal at this analytical point is 10 centimeters. Accordingly, a focusing lens 3, having a focal length at least ten times or more the maximum "i~
.
:
~z~s~
vertical movement, i.e., 100 centimeter or more may be used.
However, a lens having a focal length of 170 centimeter was used so that the light introducing system and so on were not subjected to a radiant heat of the hot metal to an excessive extent. The light emitted by the irradiation of laser was adopted to form its image at the inlet slit 14 of the spectroscope by the li~ht introducing system constituted by the concave mirror 8, the plane mirrors 9a and 9b. To prevent this light introducing system from being contaminated by gases and dust, argon gas was blown in through the argon gas introduction portion 6. Further, to ensure the prevention of the contamination completely, an argon gunning pipe 16 was mounted to the lower portion of the light introducing system, and argon gas was further blown in through an additional argon gas blown in portion 17. The spectroscope 10 spectrally separated by use of a diffraction gratin~ of 2400 line/mm at a focal length of 200 centimeter and the spectrum intensity was detected by a photomultiplier tube 1~. Table 1 shows the elements analyzed, the wavelengths of spectra and the results of analysis. The results of conventional method, in which the samples were collected, left at rest in crucibles and analyzed, were additionally shown in this table. The results of analysis according to the present invention well coincide with those obtained by the conventional method.
,-q ~L~Z~
Table 1 Wavelength Results of analysis (%) Element nanometer Present method Conventional method Si 212.4 0.40 0.37 Mn 293.3 0.39 0.44 Cr 267.7 0.021 0.023 Ni 231.6 0.018 0.016 ~r -.....
:
.~
:
Claims (9)
1. A method of performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample, which includes a vertically moving surface, comprising the steps of:
a) providing a focusing lens having a focal length f 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;
b) controlling the relationship between L and f such that the formula:
0.95f ? L ? 1.05f is constantly satisfied; and c) spectroscopically analyzing the light emitted by said substance to be measured when said substance is irradiat-ed by a high power pulse laser.
a) providing a focusing lens having a focal length f 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;
b) controlling the relationship between L and f such that the formula:
0.95f ? L ? 1.05f is constantly satisfied; and c) spectroscopically analyzing the light emitted by said substance to be measured when said substance is irradiat-ed by a high power pulse laser.
2. A method of continuously analyzing a flowing fluid sample by laser as set forth in claim 1, wherein said pulse laser is an infrared ray pulse laser.
3. A method of performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample as set forth in claim 1, wherein materials other than the subs-tance to be measured which are present on the surface of said substance to be measured are blown away by an inert gas.
4. A method of performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample as set forth in claim 1, wherein materials other than the subs-tance to be measured which are present on the surface of said substance to be measured are separated from said substance by an obstacle.
5. An apparatus for performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample having a surface which moves in the vertical direc-tion, comprising:
a) a laser oscillating means for generating a high output pulse laser;
b) 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 satisfies the formula:
0.95f ? L ? 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 generat-ed by said laser oscillating means onto the surface of said flowing fluid sample of the substance to be measured; and c) spectral separating means for analyzing spectro-scopically the light emitted from the surface of said subs-tance to be measured.
a) a laser oscillating means for generating a high output pulse laser;
b) 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 satisfies the formula:
0.95f ? L ? 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 generat-ed by said laser oscillating means onto the surface of said flowing fluid sample of the substance to be measured; and c) spectral separating means for analyzing spectro-scopically the light emitted from the surface of said subs-tance to be measured.
6. An apparatus for performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample by laser as set forth in claim 5, wherein an inert gas is blown into a light introducing system for introducing said emitted light into said spectrally separating means.
7. An apparatus for performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample which includes a vertically moving surface, comprising:
a) a laser oscillating means for generating a high output pulse laser;
b) 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 sam-ple of the substance to be measured for focusing the laser generated by said laser oscillating means onto a surface of the substance to be measured;
c) means for controlling the distance L such that the relationship between L and f can constantly satisfy the formula:
0.95f ? L ? 1.05f; and d) spectral separating means for analyzing spectros-copically the light emitted from the surface of said substance to be measured.
a) a laser oscillating means for generating a high output pulse laser;
b) 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 sam-ple of the substance to be measured for focusing the laser generated by said laser oscillating means onto a surface of the substance to be measured;
c) means for controlling the distance L such that the relationship between L and f can constantly satisfy the formula:
0.95f ? L ? 1.05f; and d) spectral separating means for analyzing spectros-copically the light emitted from the surface of said substance to be measured.
8. An apparatus for performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample by laser as set forth in claim 7, wherein said means for controlling L is a runner through which said substance to be measured flows.
9. An apparatus for performing continuous on-line laser emission spectroscopic analysis on a flowing fluid sample by laser as set forth in claim 7, wherein said means for controlling L is one for controlling the inclination of a melting furnace, out of which said substance to be measured flows.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000469782A CA1225844A (en) | 1984-12-11 | 1984-12-11 | Method of continuously analyzing fluidized body by laser and apparatus therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000469782A CA1225844A (en) | 1984-12-11 | 1984-12-11 | Method of continuously analyzing fluidized body by laser and apparatus therefor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1225844A true CA1225844A (en) | 1987-08-25 |
Family
ID=4129351
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000469782A Expired CA1225844A (en) | 1984-12-11 | 1984-12-11 | Method of continuously analyzing fluidized body by laser and apparatus therefor |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1225844A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109596601A (en) * | 2018-12-24 | 2019-04-09 | 河钢股份有限公司 | A kind of device and method of rapid Optimum laser induced breakdown spectroscopy lens distance |
-
1984
- 1984-12-11 CA CA000469782A patent/CA1225844A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109596601A (en) * | 2018-12-24 | 2019-04-09 | 河钢股份有限公司 | A kind of device and method of rapid Optimum laser induced breakdown spectroscopy lens distance |
| CN109596601B (en) * | 2018-12-24 | 2024-03-22 | 河钢股份有限公司 | Device and method for rapidly optimizing laser-induced breakdown spectroscopy lens distance |
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