Patents by Inventor Devi Chalasani
Devi Chalasani has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6372033Abstract: Powder mixtures and a method of forming and shaping the mixtures. The method involves compounding the components of powder materials, binder, solvent for the binder, surfactant, and non-solvent with respect to at least the binder, the solvent, and the powder materials. The non-solvent is lower in viscosity than the binder combined with the solvent. The solvent is present in an amount that is less than the amount that would be present otherwise. The components are mixed and plasticized, and shaped to form a green body. The choice of components results in improved wet green strength in the green body. The method is especially useful for extrusion processing of aqueous binder systems such as water and cellulose ethers and hydrophobic non-solvents, to form structures such as honeycombs. In the body, the ratio, upon subsequent firing, of the isostatic strength to the A-axis strength is at least about 20% higher than in bodies made without the mixture composition of the invention.Type: GrantFiled: February 11, 2000Date of Patent: April 16, 2002Assignee: Corning IncorporatedInventors: Devi Chalasani, Michael Fischer, Christopher J. Malarkey, Kevin R. McCarthy, Brian E. Stutts, Michael E. Zak
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Patent number: 6368992Abstract: A binder system for use in the formation of ceramic or other powder-formed greenware comprising a binder, a solvent for the binder, a surfactant, and a component that is non-solvent with respect to the binder and solvent. The non-solvent component exhibits a lower viscosity than the solvent when containing the binder and comprises a low molecular weight oil having a 90% recovered distillation temperature range of between about 220 to 400° C. Also disclosed is a process of forming and shaping plasticized powder mixtures and a process for forming ceramic articles utilizing the binder system.Type: GrantFiled: June 28, 2000Date of Patent: April 9, 2002Assignee: Corning IncorporatedInventors: Douglas M. Beall, Devi Chalasani, Christopher J. Malarkey
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Patent number: 6344078Abstract: A binder system for use in the formation of ceramic or other powder-formed greenware comprising a binder, a solvent for the binder, a surfactant, and a component that is non-solvent with respect to the binder and solvent. The non-solvent component exhibits a lower viscosity than the solvent when containing the binder and comprises at least a portion of an organic liquid having a 90% recovered distillation temperature of no greater than about 225° C. and more preferably less than 220° C. Also disclosed is a process of forming and shaping plasticized powder mixtures and a process for forming ceramic articles utilizing the binder system.Type: GrantFiled: June 28, 2000Date of Patent: February 5, 2002Assignee: Corning IncorporatedInventors: Douglas M. Beall, Devi Chalasani, Ronald E. Johnson
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Patent number: 6300266Abstract: A plasticizable raw material mixture for use in preparing a substrate having cordierite as its primary phase with the mixture comprised of a chemical composition, percent by weight, of 11 to 17% MgO, 33 to 41% Al2O3 and, 46 to 53% SiO2. The raw material mixture specifically comprises the following: (1) one source of Al2O3 and SiO2 comprising a clay mixture having less than about 22%, by weight based on the total raw materials in the plasticizable mixture, of calcined clay; (2) an alumina yielding precursor comprising alumina having an average particle diameter of about 1 &mgr;m or less; and, (3) at least one source of magnesia having an average particle diameter of between about 3 to 15 microns.Type: GrantFiled: July 16, 1999Date of Patent: October 9, 2001Assignee: Corning IncorporatedInventors: Douglas M. Beall, Devi Chalasani
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Patent number: 6299678Abstract: A binder system for use in the formation of ceramic or other powder-formed greenware comprising a binder, a solvent for the binder, a surfactant, and a component that is non-solvent with respect to the binder and solvent. The non-solvent component exhibits a lower viscosity than the solvent when containing the binder and comprises at least a portion of a branched chain paraffin exhibiting a 90% recovered distillation temperature ranging between 205° C. to about 225° C. and a carbon chain length comprised predominantly of carbon chain distributions ranging from 12 to 14. Also disclosed is a process of forming and shaping plasticized powder mixtures and a process for forming ceramic articles utilizing the binder system.Type: GrantFiled: December 13, 2000Date of Patent: October 9, 2001Assignee: Corning IncorporatedInventors: Douglas M. Beall, Devi Chalasani
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Patent number: 6241940Abstract: A binder system for use in the formation of ceramic or other powder-formed greenware including a binder, a solvent for the binder, a surfactant, and a component that is non-solvent with respect to the binder and solvent. The non-solvent component exhibits a lower viscosity than the solvent when containing the binder and includes a low molecular weight oil having a 90% recovered distillation temperature range of between about 220 to 400° C. Also disclosed is a process of forming and shaping plasticized powder mixtures and a process for forming ceramic articles utilizing the binder system.Type: GrantFiled: May 27, 1999Date of Patent: June 5, 2001Assignee: Corning IncorporatedInventors: Douglas M. Beall, Devi Chalasani, Christopher J. Malarkey
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Patent number: 6207101Abstract: A fired body and method of making involves compounding powder, binder, aqueous solvent for the binder, surfactant, and non-solvent with respect to at least the binder, the solvent, and the powder, with the addition of an organosilicon compound. The non-solvent is lower in viscosity than the binder combined with the solvent, and the amount of solvent is less than the amount that would be used absent the non-solvent. The components are mixed and plasticized and then shaped into a green body, which is then fired to produce the product body. The organosilicon compound enhances the stiffness in the green body afforded by other non-solvents, and results in increased strength and reduced cracking in the fired body, among other advantages.Type: GrantFiled: September 30, 1999Date of Patent: March 27, 2001Assignee: Corning IncorporatedInventors: Douglas M. Beall, Devi Chalasani, Gregory Albert Merkel, Y. Lisa Peng
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Patent number: 6132671Abstract: A binder system for use in the formation of ceramic or other powder-formed greenware which includes a binder, a solvent for the binder, a surfactant, and a component that is non-solvent with respect to the binder and solvent. The non-solvent component exhibits a lower viscosity than the solvent when containing the binder and includes at least a portion of an organic liquid having a 90% recovered distillation temperature of no greater than about 225.degree. C. and more preferably less than 220.degree. C. Also disclosed is a process of forming and shaping plasticized powder mixtures and a process for forming ceramic articles utilizing the binder system.Type: GrantFiled: May 27, 1999Date of Patent: October 17, 2000Assignee: Corning IncorporatedInventors: Douglas M. Beall, Devi Chalasani, Ronald E. Johnson
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Patent number: 6113829Abstract: A method for forming and shaping powder mixtures involves compounding, homogenizing, and plasticizing components to form a mixture. The components are powder materials, binder, solvent for the binder, surfactant, and non-solvent with respect to at least the binder, the solvent, and the powder materials. The non-solvent is lower in viscosity than the binder combined with the solvent. The components are chosen to result in improved wet green strength in the subsequently formed green body. The compounding is done by the steps of dry-mixing the powder material, surfactant and binder to form a uniform blend, adding the solvent to the resulting dry blend, and thereafter adding the non-solvent to the blend. The mixture is shaped by passing it through a low to moderate shear extruder, and then through a die to form a green body. The compounding and shaping steps are carried out at a temperature of no greater than ambient temperature. The method is especially suitable for RAM extrusion.Type: GrantFiled: July 15, 1998Date of Patent: September 5, 2000Assignee: Corning IncorporatedInventors: Andrea W. Bookbinder, Devi Chalasani, Gregory P. Dillon, Kevin R. McCarthy, Brian E. Stutts, Michael E. Zak
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Patent number: 6080345Abstract: Powder mixtures and a method of forming and shaping the mixtures. The method involves compounding the components of powder materials, binder, solvent for the binder, surfactant, and non-solvent with respect to at least the binder, the solvent, and the powder materials. The non-solvent is lower in viscosity than the binder combined with the solvent. The solvent is present in an amount that is less than the amount that would be present otherwise. The components are mixed and plasticized, and shaped to form a green body. The choice of components results in improved wet green strength in the green body. The method is especially useful for extrusion processing of aqueous binder systems such as water and cellulose ethers and hydrophobic non-solvents, to form structures such as honeycombs. In the body, the ratio, upon subsequent firing, of the isostatic strength to the A-axis strength is at least about 20% higher than in bodies made without the mixture composition of the invention.Type: GrantFiled: July 15, 1998Date of Patent: June 27, 2000Assignee: Corning IncorporatedInventors: Devi Chalasani, Michael Fischer, Christopher J. Malarkey, Kevin R. McCarthy, Brian E. Stutts, Michael E. Zak
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Patent number: 5966582Abstract: A method for extruding a stiffer powder mixture at lower extrusion pressure involves providing an aqueous mixture of inorganic powder that can be metal, ceramic, glass, glass ceramic, molecular sieve, and/or carbon, fatty acid the main chain of which has at least 12 carbon atoms, thermally gellable cellulose ether binder, and wax that can be paraffin and/or propylene glycol hydroxystearate, wherein the powder is coated with the fatty acid component. If clay is included in the mixture, it is provided as either calcined or hydrous. The mixture is passed through an extruder and through an extrusion die to produce a green extrudate at an extrusion pressure that is equal to or lower than it would be absent the combination of the fatty acid, the cellulose ether binder, and the wax. The mixture in the extruder and the extrudate are stiffer than without this combination.Type: GrantFiled: October 17, 1997Date of Patent: October 12, 1999Assignee: Corning IncorporatedInventors: Devi Chalasani, Ronald E. Johnson
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Patent number: 5884138Abstract: An improvement in a method of extruding a plasticized inorganic powder mixture having a plasticizing organic binder carried in an aqueous vehicle, by passing the mixture through an extruder and then through a die to produce an extrudate. The improvement involves homogeneously blending in the extruder as part of the mixture, carbon dioxide in the supercritical and/or liquid form, to lower the viscosity of the mixture and produce an extrudate that is stiffer in a shorter time than it would be, absent the carbon dioxide, without increasing the extrusion pressure.Type: GrantFiled: June 4, 1997Date of Patent: March 16, 1999Assignee: Corning IncorporatedInventors: Devi Chalasani, Ronald E. Johnson, Christopher J. Malarkey
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Patent number: 5824143Abstract: Plasticized inorganic powder batches comprising a cellulosic binder, water, and at least one inorganic powder exhibiting relatively high water affinity are compounded by combining the inorganic powder, prior to any contact with the water or cellulosic binder, with an organic surface treatment agent to decrease the water affinity thereof; subsequent mixing of the treated powder with the water and the cellulosic binder forms a plasticized inorganic powder batch with improved extrusion, molding, or other shaping characteristics.Type: GrantFiled: October 17, 1997Date of Patent: October 20, 1998Assignee: Corning IncorporatedInventors: Devi Chalasani, Robert J. Locker, Constance B. Sawyer
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Patent number: 5797081Abstract: An improvement in a method of extruding a plasticized powder mixture having a thermally gellable binder carried in an aqueous vehicle, by passing the mixture through an extruder and then through a die to produce an extrudate, the improvement being the additional step of contacting the extrudate directly after it leaves the die with an agent for simultaneously lowering the gel point of the binder and dehydrating the extrudate. The result is a stiffening of the extrudate in a shorter time than it would be, absent the additional step.Type: GrantFiled: May 7, 1997Date of Patent: August 18, 1998Assignee: Corning IncorporatedInventors: Kevin R. Brundage, Devi Chalasani, Ronald E. Johnson
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Patent number: 5547622Abstract: Fiber-reinforced, ceramic composite articles are manufactured by contacting inorganic reinforcing fibers with liquid dispersions containing powders of the ceramic matrix materials and an organic binder. The organic binder is a water-soluble polymer. The fibers coated with the ceramic powders are contacted with a cross-linking agent which reacts with binder to form a gel.Type: GrantFiled: March 15, 1995Date of Patent: August 20, 1996Assignee: Corning IncorporatedInventors: Devi Chalasani, Mark S. Friske, Ronald E. Johnson