Gas treatment of molten metals
First Claim
1. A method of treating a molten metal with a treatment gas within a treatment zone in a container formed in the shape of a trough having a bottom wall and opposed side walls, comprising:
- mechanically moving one or more gas injectors within molten metal contained in the treatment zone in a manner selected from the group consisting of rotary, oscillatory and vibrational movement; and
introducing a treatment gas into the molten metal via said gas injectors;
wherein each gas injector has an associated treatment segment consisting of a portion of the metal within the treatment zone contained within a volume surrounding the gas injector, said volume being defined by a length equal to the distance between the opposed walls of the container at an upper surface of the molten metal and a vertical transverse cross-section area of the container at said injector; and
wherein the volume of the treatment segment does not exceed 0.07 m3.
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Accused Products
Abstract
A method of and apparatus for treating molten metal to achieve effective removal of such unwanted inclusions as gases, alkali metals, entrained solids, and the like. The method comprises introducing molten metal into a trough, such as the trough provided between a melting furnace and a casting machine, providing at least one mechanically movable gas injector submerged within the metal in the trough and injecting a gas into the metal in a part of the trough forming a treatment zone through the injector(s) to form gas bubbles in the metal while moving the injector(s) mechanically to minimize bubble size and maximize distribution of the gas within the metal. The injectors are preferably rotated and comprise a rotor body having a cylindrical side surface and a bottom surface, at least three openings in the side surface spaced symmetrically around the rotor body, at least one opening in the bottom surface, and at least one internal passageway for gas delivery and an internal structure for interconnecting the openings in the side surface, the openings in the bottom surface and the internal passageway. The internal structure is adapted to cause gas bubbles emanating from the internal passageway to break up into finer bubbles and to cause a metal/gas mixture to issue from the openings in the side surface in a generally horizontal and radial manner.
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Citations
43 Claims
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1. A method of treating a molten metal with a treatment gas within a treatment zone in a container formed in the shape of a trough having a bottom wall and opposed side walls, comprising:
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mechanically moving one or more gas injectors within molten metal contained in the treatment zone in a manner selected from the group consisting of rotary, oscillatory and vibrational movement; and introducing a treatment gas into the molten metal via said gas injectors; wherein each gas injector has an associated treatment segment consisting of a portion of the metal within the treatment zone contained within a volume surrounding the gas injector, said volume being defined by a length equal to the distance between the opposed walls of the container at an upper surface of the molten metal and a vertical transverse cross-section area of the container at said injector; and wherein the volume of the treatment segment does not exceed 0.07 m3.
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2. A method of treating a molten metal with a treatment gas, comprising:
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introducing the metal into a section of a trough having a bottom wall and opposed side walls, said trough section being such that said section exhibits a static to dynamic holdup of less than about 50%, providing at least one mechanically movable gas injector within the metal in the trough section; and injecting a gas into the metal in a part of the trough section forming a treatment zone via said at least one injector to form gas bubbles in the metal while moving said at least one injector mechanically to minimize bubble size and maximize distribution of said gas within said metal. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of treating a molten metal with a treatment gas within a treatment zone in a container formed in the shape of a trough having a bottom wall and opposed side walls, comprising:
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mechanically moving one or more gas injectors within molten metal contained in the treatment zone in a manner selected from the group consisting of rotary, oscillatory and vibrational movement; and introducing a treatment gas into the molten metal via the gas injectors; wherein each gas injector has an associated treatment segment consisting of a portion of the metal within the treatment zone contained within a volume surrounding the gas injector where the volume is defined by a length equal to the distance between the opposed walls of the container at an upper surface of the molten metal and a transverse vertical cross-section area of the metal within the container at the injector; and wherein the gas injectors are operated to increase a volume of the portion of the metal in each treatment segment by at least 5% due to introduction of the treatment gas compared to a condition in which the injectors are operated without gas introduction.
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23. A method of treating a molten metal with a treatment gas, comprising:
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continuously introducing the molten metal into a container having a bottom wall and opposed side walls; continuously removing the molten metal from said container; providing at least one mechanically movable gas injector within the metal in the container; and injecting a gas into the metal in a part of the container forming a treatment zone via said at least one injector to form gas bubbles in the metal while moving at least one injector mechanically; wherein said container is a section of a trough, said trough section exhibiting a static to dynamic metal holdup of less than about 50%. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A method of treating a molten metal with a treatment gas within a treatment zone in a container formed in the shape of a trough having a bottom wall and opposed side walls, comprising:
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mechanically moving one or more gas injectors within molten metal contained in the treatment zone in a manner selected from the group consisting of rotary, oscillatory and vibrational movement; and introducing a treatment gas into the molten metal via said gas injectors; wherein each gas injector has an associated treatment segment consisting of a portion of the metal within the treatment zone contained within a volume surrounding the gas injector, said volume being defined by a length equal to the distance between the opposed walls of the container at an upper surface of the molten metal and a vertical transverse cross-section area of the container at said injector; and wherein an integrated gas metal surface area in each treatment segment is at least 30 m2 per m3 of metal.
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Specification