Patents Assigned to RDP Company
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Patent number: 8133401Abstract: A method and apparatus is provided for conveying lime slurry, removing and controlling the amount of grit, and feeding lime slurry, wherein the lime slurry moves through a recirculation loop, and wherein gravity removal of grit from the lime slurry takes place.Type: GrantFiled: April 14, 2005Date of Patent: March 13, 2012Assignee: RDP CompanyInventors: Paul G. Christy, Michael Quici
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Patent number: 7669348Abstract: An apparatus, method and system is provided for treating sewage sludge by heating the same in a container to drive off pathogens and/or pasteurize the sewage sludge while the material is tumbled in the container and with moisture gases being evaporated therefrom and drawn off from the container. After treatment the treated sludge is discharged from the container. There is provided at least one weight-responsive member on which the container is mounted, and a control is provided connected to the one or more weight-responsive member whereby the solids content of the treated material can be determined by measuring the difference in weight of material in the container, before and after moisture is drawn off from the material and prior to its discharge from the drum. The control is preferably effected by means of a computer.Type: GrantFiled: October 10, 2006Date of Patent: March 2, 2010Assignee: RDP CompanyInventors: Richard W. Christy, Robert Van Bramer, Michael Quici
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Patent number: 7416673Abstract: A method and apparatus is provided for conveying lime slurry, removing and controlling the amount of grit, and feeding lime slurry, wherein the lime slurry moves through a recirculation loop, and wherein gravity removal of grit from the lime slurry takes place. A stilling well is provided, inside or outside the slurry tank, either fixed in cross-sectional area or adjustable, but wherein the cross-sectional area of the stilling tank can be selected or adjusted to alter the flow velocity of slurry therethrough and the residence time of slurry therethrough, as slurry is delivered through the stilling well via a suction line located therein, whereby grit can be separated via gravity from slurry in the slurry tank prior to withdrawal of slurry through the stilling well.Type: GrantFiled: March 31, 2006Date of Patent: August 26, 2008Assignee: RDP CompanyInventors: Paul G. Christy, Michael Quici
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Publication number: 20080185324Abstract: A method and apparatus is provided for conveying lime slurry, removing and controlling the amount of grit, and feeding lime slurry, wherein the lime slurry moves through a recirculation loop, and wherein gravity removal of grit from the lime slurry takes place.Type: ApplicationFiled: April 8, 2008Publication date: August 7, 2008Applicant: RDP CompanyInventors: Paul G. Christy, Michael Quici
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Patent number: 5851404Abstract: A process and apparatus for treatment of sludge is provided. The process includes providing sludge in a substantially liquid form and an alkaline additive to a preferably substantially closed reactor vessel, mixing the sludge and additive to ensure said pH is greater than about 12, maintaining the pH for a predetermined period of time, optionally applying supplemental heat to the sludge mixture in the reactor vessel to a predetermined elevated temperature for a predetermined period of time, maintaining the sludge mixture in a substantially fluid liquid condition, and discharging the sludge and additive mixture from the reactor vessel in a substantially liquid form such that it lends itself to be handled by gravity flow. The apparatus provides means to accomplish the above process.Type: GrantFiled: January 28, 1997Date of Patent: December 22, 1998Assignee: RDP CompanyInventors: Richard W. Christy, Paul G. Christy
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Patent number: 5783073Abstract: A process and apparatus for treatment of sludge is provided. The process includes providing sludge in a substantially liquid form and an alkaline additive to a preferably substantially closed reactor vessel, mixing the sludge and additive to ensure said pH is greater than about 12, maintaining the pH for a predetermined period of time, optionally applying supplemental heat to the sludge mixture in the reactor vessel to a predetermined elevated temperature for a predetermined period of time, maintaining the sludge mixture in a substantially fluid liquid condition, and discharging the sludge and additive mixture from the reactor vessel in a substantially liquid form such that it lends itself to be handled by gravity flow. The apparatus provides means to accomplish the above process.Type: GrantFiled: January 28, 1997Date of Patent: July 21, 1998Assignee: RDP CompanyInventors: Richard W. Christy, Paul G. Christy
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Patent number: 5681481Abstract: A process and apparatus for treatment of sludge is provided. The process includes providing sludge in a substantially liquid form and an alkaline additive to a preferably substantially closed reactor vessel, mixing the sludge and additive to ensure said pH is greater than about 12, maintaining the pH for a predetermined period of time, optionally applying supplemental heat to the sludge mixture in the reactor vessel to a predetermined elevated temperature for a predetermined period of time, maintaining the sludge mixture in a substantially fluid liquid condition, and discharging the sludge and additive mixture from the reactor vessel in a substantially liquid form such that it lends itself to be handled by gravity flow. The apparatus provides means to accomplish the above process.Type: GrantFiled: May 18, 1995Date of Patent: October 28, 1997Assignee: RDP CompanyInventors: Richard W. Christy, Paul G. Christy
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Patent number: 5618442Abstract: A process and apparatus for treating sewage sludge having the steps of providing sludge at a desired rate, mixing the sludge with at least one alkaline additive at a proportionate rate to the sludge to raise the pH of the mixture to at least a desired level, providing a pasteurization chamber having a means to heat the contents of the chamber, continuously delivering the sludge and alkaline additive mixture to the inlet opening of the pasteurization chamber, heating the pasteurization chamber to maintain a minimum temperature of the sludge and alkaline additive mixture in the pasteurization chamber, continuously conveying the sludge and alkaline additive mixture without any substantial agitation of the mixture for a desired duration through the pasteurization chamber such that the thixotropic mixture does not become watery, and continuously discharging the sludge and alkaline additive mixture from the discharge opening of the pasteurization chamber, whereby harmful pathogens are destroyed in the sludge.Type: GrantFiled: June 11, 1996Date of Patent: April 8, 1997Assignee: RDP CompanyInventor: Paul G. Christy
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Patent number: 5554279Abstract: A process and apparatus for treating sewage sludge having the steps of providing sludge at a desired rate, mixing the sludge with at least one alkaline additive at a proportionate rate to the sludge to raise the pH of the mixture to at least a desired level, providing a pasteurization chamber having a means to heat the contents of the chamber, continuously delivering the sludge and alkaline additive mixture to the inlet opening of the pasteurization chamber, heating the pasteurization chamber to maintain a minimum temperature of the sludge and alkaline additive mixture in the pasteurization chamber, continuously conveying the sludge and alkaline additive mixture without any substantial agitation of the mixture for a desired duration through the pasteurization chamber such that the thixotropic mixture does not become watery, and continuously discharging the sludge and alkaline additive mixture from the discharge opening of the pasteurization chamber, whereby harmful pathogens are destroyed in the sludge.Type: GrantFiled: September 26, 1994Date of Patent: September 10, 1996Assignee: RDP CompanyInventor: Paul G. Christy
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Patent number: 5433844Abstract: Apparatus and process for pathogen reduction in waste where dewatered sludge having a solids content in the range of 10-60% is mixed with a selected alkaline additive selected from the group consisting of calcium oxide or calcium carbonate group. Hydration to calcium hydroxide occurs with an attendant release of heat. The pH of the sludge is then elevated and the heat of the hydration reaction is retained. Supplemental heat is added to the sludge, either to preheat the sludge prior to mixing it, or while mixing it, or both, such that effective neutralization of pathogens results. The supplemental heat is added by indirectly heating the sludge by heat generated by electric elements carried either in the mixing member, or by the chamber, or both, with electric power being supplied from outside the chamber.Type: GrantFiled: November 11, 1994Date of Patent: July 18, 1995Assignee: RDP CompanyInventor: Paul G. Christy
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Patent number: 5405536Abstract: Process for pathogen reduction in waste where dewatered sludge having a solids content in the range of 10-60% is mixed with a selected alkaline additive selected from the group consisting of calcium oxide or calcium carbonate group. Hydration to calcium hydroxide occurs with an attendant release of heat. The pH of the sludge is then elevated and the heat of the hydration reaction is retained. Supplemental heat is added to the sludge, either to preheat the sludge prior to mixing it, or while mixing it, or both, such that effective neutralization of pathogens results. The supplemental heat is added by indirectly heating the sludge by heat generated by electric elements carried either in the mixing member, or by the chamber, or both, with electric power being supplied from outside the chamber.Type: GrantFiled: July 28, 1993Date of Patent: April 11, 1995Assignee: RDP CompanyInventor: Paul G. Christy
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Patent number: 5401402Abstract: A method of treating sewage sludge is provided, in which the sludge is mixed with an alkaline material in such a way as to provide intimate surface contact that enables the alkaline material to permeate even small particles of the sludge, and to deliver the resultant product in a granular, scatterable form. The sludge and alkaline material are delivered to a mixing chamber and are confronted therein with a screw type mixer having generally helical flighting carried by a shaft, with the mixer being rotatably driven in generally horizontal arrangement to convey the mixture toward an outlet, with the mixture that is being mixed being maintained at a level in the mixer such that a spiral rolling action is imparted to the sludge and alkaline additive by the flighting engaging particles of sludge and rolling those particles up over the rotating shaft of the screw mixer.Type: GrantFiled: March 30, 1994Date of Patent: March 28, 1995Assignee: RDP CompanyInventors: Paul G. Christy, Richard W. Christy
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Patent number: 5346616Abstract: An apparatus for pathogen reduction in waste where dewatered sludge having a solids content in the range of 10-60% is mixed with an additive selected from the group consisting of calcium oxide or calcium carbonate group. Hydration to calcium hydroxide occurs with an attendant release of heat. The pH of the sludge is then elevated and the heat of the hydration reaction is retained resulting in effective neutralization of pathogens.Type: GrantFiled: November 3, 1992Date of Patent: September 13, 1994Assignee: RDP CompanyInventors: Robert W. Christy, Sr., Paul G. Christy
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Patent number: 5186840Abstract: A method of treating sewage sludge is provided, in which the sludge is mixed with an alkaline material in such a way as to provide intimate surface contact that enables the alkaline material to permeate even small particles of the sludge, and to deliver the resultant product in a granular, scatterable form. The sludge and alkaline material are delivered to a mixing chamber and are confronted therein with a screw type mixer having generally helical flighting carried by a shaft, with the mixer being rotatably driven in generally horizontal arrangement to convey the mixture toward an outlet, with the mixture that is being mixed being maintained at a level in the mixer such that a spiral rolling action is imparted to the sludge and alkaline additive by the flighting engaging particles of sludge and rolling those particles up over the rotating shaft of the screw mixer.Type: GrantFiled: August 26, 1991Date of Patent: February 16, 1993Assignee: RDP CompanyInventors: Paul G. Christy, Richard W. Christy
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Patent number: 5013458Abstract: A process for pathogen reduction in waste where dewatered sludge having a solids content in the range of 10-60% is mixed with an additive selected from the group consisting of calcium oxide or calcium carbonate group. Hydration to calcium hydroxide occurs with an attendant release of heat. The pH of the sludge is then elevated and the heat of the hydration reaction is retained resulting in effective neutralization of pathogens. Apparatus is also disclosed.Type: GrantFiled: April 6, 1990Date of Patent: May 7, 1991Assignee: RDP CompanyInventors: Robert W. Christy, Sr., Paul G. Christy