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US 5,204,270 AGranted
Multiple sample characterization of coals and other substances by controlled-atmosphere programmed temperature oxidation
OwnerRobert B. LaCountinventor
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OwnerRobert B. LaCountinventor
Estimating the term…
A furnace with two hot zones holds multiple analysis tubes. Each tube has a separable sample-packing section positioned in the first hot zone and a catalyst-packing section positioned in the second hot zone. A mass flow controller is connected to an inlet of each sample tube, and gas is supplied to the mass flow controller. Oxygen is supplied through a mass flow controller to each tube to either or both of an inlet of the first tube and an intermediate portion between the tube sections to intermingle with and oxidize the entrained gases evolved from the sample. Oxidation of those gases is completed in the catalyst in each second tube section. A thermocouple within a sample reduces furnace temperature when an exothermic condition is sensed within the sample. Oxidized gases flow from outlets of the tubes to individual gas cells. The cells are sequentially aligned with an infrared detector, which senses the composition and quantities of the gas components. Each elongated cell is tapered inward toward the center from cell windows at the ends. Volume is reduced from a conventional cell, while permitting maximum interaction of gas with the light beam. Reduced volume and angulation of the cell inlets provide rapid purgings of the cell, providing shorter cycles between detections. For coal and other high molecular weight samples, from 50% to 100% oxygen is introduced to the tubes.
A furnace comprising first and second hot zones, a plurality of tubes each having separable sample-receiving and catalyst-holding sections in the first zone and the second zone respectively, a catalyst positioned in sections of the tubes in the second zone, and sample-receiving sections in tubes in the first zone, a gas supply for flowing gas into inlets of the sample-receiving sections of the tubes in the first zone, for flowing gases through the samples and entraining gases from the samples, the gas supply including an oxygen source selectively connected to the tubes between the first and second zones for selectively flowing oxygen into the tubes between the sections for oxidizing pyrolysis gases before and as the gases flow through the catalyst in the tubes in the second hot zone, gas conduits connected to outlets of the catalyst-holding sections of the tubes and connected severally to inlets of a like plurality of analysis cells for supplying oxidized gas to the gas analysis cells, and exhaust lines connected to the gas analysis cells for flowing gas out from the analysis cells, wherein the plural cells are aligned parallel to each other and are mounted on a slide, further comprising a motor for moving the slide transversely, and further comprising an infrared light beam source for projecting an energy beam through the plural cells, and a detector aligned with the source on an opposite side of the slide for receiving light projected through the plural cells, the motor and slide cooperating for moving each cell into alignment and out of alignment with the infrared light beam source.
A method of quantitatively analyzing multiple samples, comprising providing plural sample tubes, packing samples in plural first sample tube sections, packing catalyst in plural second catalyst tube sections, connecting each of the sample tube sections with a catalyst tube section, placing the connected sample and catalyst tube sections in horizontal communicating alignment in a furnace having a first hot zone which receives the first tube sections, and a second hot zone which receives the second tube sections, heating the first hot zone to uniformly increasing temperatures, and heating the second hot zone to a constant elevated temperature, introducing gas into an inlet of each sample tube, the gas containing at least 50% oxygen, entraining heated resultant gases from the samples within the sample tube sections and partially oxidizing with the introduced gas, and mixing the introduced gas and the entrained resultant gases, oxidizing the entrained resultant gases in the heated catalyst within the catalyst tube sections, and completing oxidization of the entrained resultant gases and forming oxidation gases, flowing all of the gases out of outlets of the catalyst tube sections and into inlets in plural gas cells connected separately to the outlets of the second catalyst-holding tube sections, flowing all of the gases through the gas cells and releasing the gases from the gas cells under pressure regulation, selectively moving the gas cells into alignment with an infrared beam and detecting influence on the infrared beam by gas within the cells with an electronic detector, increasing temperature within the first hot zone at a slow rate of increase, and sequentially positioning the cells within the infrared light beam and detector during the increase in temperature in the first hot zone for determining gases released from the samples and entrained and oxidized, and thereby determining content of the sample.
A gas analyzing apparatus comprising plural gas cells aligned parallel and mounted on a slide, a motor for moving the slide transversely, an infrared light beam source for projecting an infrared light beam through the cells, and a detector aligned with the source on an opposite side of the slide for receiving light projected through the cells, the motor and slide cooperating for moving each cell into alignment and out of alignment with the infrared light beam source.
A combustion tube sample analyzing apparatus comprising a tube, a furnace for heating a sample-holding portion of the tube, and a thermocouple embedded in the sample within the tube and programmed control means responsive to the thermocouple in the sample for stopping furnace heating immediately upon internally sensing exothermic reaction in the sample.
Dependencies are inferred from the claim text.