Furnace system for and method of melting and preheating metal
AssigneeReynolds Metals Company
InventorsJack A. Ferguson, Clarence D. Korn
Life of this patent
Estimating the term…
Abstract
This invention provides a furnace system for and method of melting metal charges which utilizes hot gases generated by a burner, and are ordinarily discharged from the furnace as waste, for the dual purpose of preheating metal to be subsequently melted and preheating combustion air which is used to provide more efficient operation of the furnace burner.
Claims20
A furnace system comprising, a first and a second furnace serving alternately as a melting and a preheating furnace, said first furnace having a first variable output burner and a first temperature sensor for sensing temperature of a first charge of metal therein, said second furnace having a second variable output burner and a second temperature sensor for sensing temperature of a second charge of metal therein, a connecting duct connecting said furnaces together, a recuperator, a first and a second hot gas discharge duct from said first and second furnaces respectively to said recuperator, a first and a second valve in said first and second hot gas discharge ducts respectively for controlling hot gas flow therethrough, a first and a second combustion air duct from said recuperator to said first and second burner respectively, a first and a second valve in said first and second combustion air duct respectively for controlling flow of combustion air therethrough, means for supplying combustion air to said recuperator to preheat said combustion air by hot gases provided therethrough from one of said hot gas discharge ducts, and control means for said furnace system operatively associated with said burners, temperature sensors, and valves to provide preheated combustion air to said first burner of said first furnace with said first burner operating at full output to melt a first charge of metal therein with hot gases from said first furnace flowing through said connecting duct and second furnace to preheat said second charge and said hot gases continuing through said second hot gas discharge duct to said recuperator to also preheat said combustion air which is supplied to said first burner.
A furnace system comprising, a first and a second furnace serving alternately as a melting and a preheating furnace, said first furnace having a first variable output burner and a first temperature sensor for sensing temperature of a first charge of metal therein, said second furnace having a second variable output burner and a second temperature sensor for sensing temperature of a second charge of metal therein, a connecting duct connecting said furnaces together, a recuperator, a first and a second hot gas discharge duct from said first and second furnaces respectively to said recuperator, a first and a second valve in said first and second hot gas discharge ducts respectively for controlling hot gas flow therethrough, a first and a second combustion air duct from said recuperator to said first and second burner respectively, a first and a second valve in said first and second combustion air duct respectively for controlling flow of combustion air therethrough, means for supplying combustion air to said recuperator to preheat said combustion air by hot gases provided therethrough from one of said hot gas discharge ducts, and control means for said furnace system operatively associated with said burners, temperature sensors, and valves to provide preheated combustion air to said first burner of said first furnace with said first burner operating at full output to melt a first charge of metal therein with hot gases from said first furnace flowing through said connecting duct and second furnace and said hot gases continuing through said second hot gas discharge duct to said recuperator to also preheat said combustion air which is supplied to said first burner, said control means for said system operating such that said first temperature sensor senses the temperature of said first charge and when said first charge reaches pouring temperature said first burner is turned off and said second burner is turned on whereupon said valves are operated so that preheated combustion air is supplied to said second furnace and flow of hot gases through said connecting duct is reversed while modulating the heat output of the second burner using said first temperature sensor to maintain said pouring temperature of said first charge until removal thereof, and upon recharging of said first furnace with a new charge said control means operates to transfer control of said second burner to said second temperature sensor and operate said second burner at full output to melt said second charge of metal in said second furnace with hot gases from said second furnace flowing through said connecting duct and first furnace to preheat said new charge in said first furnace with said hot gases continuing through said first hot gas discharge duct to said recuperator to also preheat said combustion air which is supplied to said second burner.
A method of melting metal comprising the steps of, providing a first and a second furnace serving alternately as a melting and a preheating furnace, said first furnace having a first variable output burner and a first temperature sensor for sensing temperature of a first charge of metal therein, said second furnace having a second variable output burner and a second temperature sensor for sensing temperature of a second charge of metal therein, joining said furnaces together with a connecting duct, installing a recuperator adjacent said furnaces, connecting a first and a second hot gas discharge duct from said first and second furnaces respectively to said recuperator, installing a first and a second valve in said first and second hot gas discharge ducts respectively for controlling hot gas flow therethrough, connecting a first and a second combustion air duct from said recuperator to said first and second burner respectively, installing a first and a second valve in said first and second combustion air duct respectively for controlling flow of combustion air therethrough, supplying combustion air to said recuperator to preheat said combustion air by hot gases provided therethrough from one of said hot gas discharge ducts, and controlling said system with a control means operatively associated with said burners, temperature sensors, and valves to provide preheated combustion air to said first burner of said first furnace with said first burner operating at full output to melt a first charge of metal therein with hot gases from said first furnace flowing through said connecting duct and second furnace to preheat a second charge in said second furnace and said hot gases continuing through said second hot gas discharge duct to said recuperator to also preheat said combustion air which is supplied to said first burner.
A method of melting metal comprising the steps of, providing a first and a second furnace serving alternately as a melting and a preheating furnace, said first furnace having a first variable output burner and a first temperature sensor for sensing temperature of a first charge of metal therein, said second furnace having a second variable output burner and a second temperature sensor for sensing temperature of a second charge of metal therein, joining said furnaces together with a connecting duct, installing a recuperator adjacent said furnaces, connecting a first and a second hot gas discharge duct from said first and second furnaces respectively to said recuperator, installing a first and a second valve in said first and second hot gas discharge ducts respectively for controlling hot gas flow therethrough, connecting a first and a second combustion air duct from said recuperator to said first and second burner respectively, installing a first and a second valve in said first and second combustion air duct respectively for controlling flow of combustion air therethrough, supplying combustion air to said recuperator to preheat said combustion air by hot gases provided therethrough from one of said hot gas discharge ducts, and controlling said system with a control means operatively associated with said burners, temperature sensors, and valves to provide preheated combustion air to said first burner to said first furnace with said first burner operating at full output to melt a first charge of metal therein with hot gases from said first furnace flowing through said connecting duct and second furnace to preheat a second charge in said second furnace and said hot gases continuing through said second hot gas discharge duct to said recuperator to also preheat said combustion air which is supplied to said first burner, said controlling step comprising operating said control means such that said first temperature sensor senses the temperature of said first charge and when said first charge reaches pouring temperature said first burner is turned off and said second burner is turned on whereupon said valves are operated so that preheated combustion air is supplied to said second furnace and flow of hot gases through said connecting duct is reversed while modulating the heat output of the second burner using said first temperature sensor to maintain said pouring temperature of said first charge until removal thereof, and recharging said first furnace with a new charge whereupon said control means operates to transfer control of said second burner to said second temperature sensor and said second burner is then operated at full output to melt said second charge of metal in said second furnace with hot gases from said second furnace flowing through said connecting duct and first furnace to preheat said new charge in said first furnace with said hot gases continuing through said first hot gas discharge duct to said recuperator to also preheat said combustion air which is supplied to said second burner.
Dependencies are inferred from the claim text.