Apparatus and method for quantitative determination of materials contained in fluids
First Claim
1. A method for investigating fluid samples having at least one material carried by particulates suspended therein the concentration of which material is to be monitored, said method comprising the steps of:
- a. flowing a known volume of a sample through filter material selected to collect the material under investigation on its surface with known efficiency;
b. causing high intensity laser radiation to interact with a significant portion of the surface of the filter material which induces dielectric breakdown to occur substantially thereon from which there is emitted electromagnetic radiation which includes ionic and neutral atomic spectral features characteristic of the elemental species present on the filter material surface portion, molecular emissions, and spectrally broad background emissions;
c. quantitatively detecting and recording the emitted radiation;
d. calibrating said quantitatively detecting and recording step by depositing known contamination levels of the material under investigation on the filter material and repeating said steps b-c; and
e. comparing said quantitatively detecting and recording step for the material under investigation with said calibrating step to determine the concentration of the material contained in the particulate in the fluid sample.
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Abstract
Apparatus and method for near real-time in-situ monitoring of particulates and vapors contained in fluids. Initial filtration of a known volume of the fluid sample is combined with laser-induced dielectric breakdown spectroscopy of the filter employed to obtain qualitative and quantitative information with high sensitivity. Application of the invention to monitoring of beryllium, beryllium oxide, or other beryllium-alloy dusts is demonstrated. Significant shortening of analysis time is achieved from those of the usual chemical techniques of analysis.
15 Citations
17 Claims
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1. A method for investigating fluid samples having at least one material carried by particulates suspended therein the concentration of which material is to be monitored, said method comprising the steps of:
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a. flowing a known volume of a sample through filter material selected to collect the material under investigation on its surface with known efficiency; b. causing high intensity laser radiation to interact with a significant portion of the surface of the filter material which induces dielectric breakdown to occur substantially thereon from which there is emitted electromagnetic radiation which includes ionic and neutral atomic spectral features characteristic of the elemental species present on the filter material surface portion, molecular emissions, and spectrally broad background emissions; c. quantitatively detecting and recording the emitted radiation; d. calibrating said quantitatively detecting and recording step by depositing known contamination levels of the material under investigation on the filter material and repeating said steps b-c; and e. comparing said quantitatively detecting and recording step for the material under investigation with said calibrating step to determine the concentration of the material contained in the particulate in the fluid sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for investigating fluid samples having at least one material carried by particulates suspended therein the concentration of which is to be monitored, said apparatus comprising in combination:
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a. a filter of known collection efficiency through which as been passed a known volume of a fluid sample and upon which a quantity of the material to be monitored has been collected; b. means for generating repetitively pulsed, high intensity laser radiation; c. cylindrical lens means for receiving the repetitively pulsed, high intensity laser radiation generated by said laser radiation generating means, and for focusing the laser radiation into an elongated shape having significant area on the surface of the filter material, thereby inducing dielectric breakdown to occur over a significant portion of substantially the surface of the filter material from which there is emitted electromagnetic radiation which includes ionic and neutral atomic spectral features characteristic of the elemental species present on the filter material surface portion, molecular emissions, and spectrally broad background emissions; d. means for quantitatively detecting and recording the emitted characteristic spectral features; and e. means for calibrating the magnitude of the quantitatively detected, emitted characteristic spectral features in order to relate the magnitude thereof to the material concentration to be monitored. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification