Method and apparatus for preheating scrap

Claim 3

A method as defined in claim 1 further comprising the step of applying additional heat to said fumes by extraneous means provided therefor in order to equalize the fluctuations in the amount of heat available in the fumes at various stages of scrap melting.

Claim 4

A method as defined in claim 2 wherein said step of applying additional heat is accompanied by the step of automatically controlling the heat generated by said extraneous means by sensing of the pressure and temperature of the fumes before and after being passed through the scrap, thereby to provide a definite, desired constant level of heat available for the purpose of preheating the scrap.

Claim 5

Apparatus for preheating scrap prior to being charged into an electric furnace comprising, in combination: a. a combustion chamber connected by a duct to the arc furnace, said combustion chamber receiving the heated fumes leaving the arc furnace; b. a hood connected to said combustion chamber by a duct; c. a stand for supporting a scrap-charging basket, said basket defining a connecting channel between said hood and said supporting stand through which the fumes from said combustion chamber flow; and d. suction means connected to said combustion chamber via a duct connected to said supporting stand, when said scrap charging basket is positioned for support on said stand, said suction means providing a constant negative pressure in the apparatus which draws the fumes generated in the arc furnace through the combustion chamber, hood, charging basket and supporting stand, in that order, thereby to cause preheating of the scrap in the charging basket.

Claim 6

Apparatus for preheating scrap prior to being charged into an electric furnace comprising, in combination: a. a combustion chamber connected by a duct to the arc furnace, said combustion chamber receiving the heated fumes leaving the arc furnace; b. a hood connected to said combustion chamber by a duct; c. a stand for supporting a scrap-charging basket, said basket defining a connecting channel between said hood and said supporting stand through which the fumes from said combustion chamber flow; and d. suction means connected to said combustion chamber via a duct connected to said supporting stand, when said scrap charging basket is positioned for support on said stand, said suction means providing a constant negative pressure in the apparatus which draws the fumes generated in the arc furnace through the combustion chamber, hood, charging basket and supporting stand, in that order, thereby to cause preheating of the scrap in the charging basket.

Claim 7

Apparatus as defined in claim 4 wherein said suction means includes a fan.

Claim 8

Apparatus as defined in claim 4 further comprising a burner located along the duct connecting said hood to said combustion chamber, said burner adding heat to said fumes, as required, prior to the passing of the fumes through the hood and scrap charging basket.

Claim 9

Apparatus as defined in claim 4 further comprising control means for regulating the temperature in the apparatus, said control means being connected to said burner for controlling the same; and at least two thermocouples connected to said control means for signalling said control means of temperature conditions sensed, said control means responding to such signals by appropriately regulating said burner.

Claim 10

Apparatus as defined in claim 7 wherein one of said two thermocouples is located between said combustion chamber and said scrap charging basket and the other one of said thermocouples is located in the duct connectiNg said supporting stand to said suction means.

Claim 11

Apparatus as defined in claim 8 further comprising at least two pressure sensing devices, said pressure-sensing devices being connected to said control means for signalling said control means of pressure conditions sensed, said control responding to such signals by appropriately regulating said fan so as to provide a constant negative pressure in said apparatus.

Claim 12

Apparatus as defined in claim 9 wherein one of said pressure sensing devices is located in said combustion chamber and one of said pressure sensing devices is located in said duct connecting the suction means to said supporting stand.

Claim 13

Apparatus for preheating scrap steel prior to being charged into an electric arc furnace, comprising, in combination: a. a combustion chamber; b. a duct connecting said combustion chamber to the arc furnace so that said combustion chamber receives heated fumes from the arc furnace; c. a hood; d. a duct connecting said hood to said combustion chamber; e. a scrap charging basket; f. a stand for supporting said scrap charging basket so that a flow path for the fumes is defined from said hood through said basket to said stand; and g. suction means connected to said stand for providing a constant negative pressure to draw the fumes generated in the arc furnace through said combustion chamber, said hook, said charging basket and said supporting stand, in that order, to cause preheating of the scrap in said charging basket.

Claim 14

Apparatus for preheating scrap steel prior to being charged into an electric arc furnace, comprising, in combination: a. a combustion chamber; b. a duct connecting said combustion chamber to the arc furnace so that said combustion chamber receives heated fumes from the arc furnace; c. a hood; d. a duct connecting said hood to said combustion chamber; e. a scrap charging basket; f. a stand for supporting said scrap charging basket so that a flow path for the fumes is defined from said hood through said basket to said stand; and g. suction means connected to said stand for providing a constant negative pressure to draw the fumes generated in the arc furnace through said combustion chamber, said hook, said charging basket and said supporting stand, in that order, to cause preheating of the scrap in said charging basket.