High efficiency system for melting molten aluminum
First Claim
1. A method of heating a body of molten aluminum contained in a heating bay, comprising the steps of:
- (a) providing a body of molten aluminum;
(b) projecting an electric powered heater into said body of molten aluminum, said heater comprised of;
(i) a sleeve suitable for immersing in said molten aluminum, the sleeve comprised of a metal or a composite material comprised of an inner layer of metal having a coefficient of thermal expansion of less than 10×
10-6 in/in/°
F. and having an outside surface having a refractory coating thereon exposed to said molten aluminum, said refractory coating resistant to attack by said molten aluminum and having a coefficient of thermal expansion of less than 10×
10-6 in/in/°
F.; and
(ii) an electric heating element located in said sleeve in heat transfer relationship therewith for adding heat to said molten aluminum, said heater operated at a watt density in the range of 25 to 350 watts/in2 ; and
(c) passing electric current through said element and adding heat to said body of molten aluminum.
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Accused Products
Abstract
A method and system of heating a body of molten aluminum, for example, contained in a heating bay, the method comprising providing a body of molten aluminum; projecting an electric powered heater into the body of molten aluminum; passing electric current through the element and adding heat to the body of molten aluminum. The heater is comprised of a sleeve suitable for immersing in the molten aluminum. The sleeve may have a closed end and is comprised of a composite material comprised of an inner layer of titanium or titanium alloy having an outside surface having a refractory coating thereon exposed to the molten aluminum, the refractory coating resistant to attack by the molten aluminum. An electric heating element is located in the sleeve in heat transfer relationship therewith for adding heat to the molten aluminum.
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Citations
35 Claims
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1. A method of heating a body of molten aluminum contained in a heating bay, comprising the steps of:
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(a) providing a body of molten aluminum; (b) projecting an electric powered heater into said body of molten aluminum, said heater comprised of; (i) a sleeve suitable for immersing in said molten aluminum, the sleeve comprised of a metal or a composite material comprised of an inner layer of metal having a coefficient of thermal expansion of less than 10×
10-6 in/in/°
F. and having an outside surface having a refractory coating thereon exposed to said molten aluminum, said refractory coating resistant to attack by said molten aluminum and having a coefficient of thermal expansion of less than 10×
10-6 in/in/°
F.; and(ii) an electric heating element located in said sleeve in heat transfer relationship therewith for adding heat to said molten aluminum, said heater operated at a watt density in the range of 25 to 350 watts/in2 ; and (c) passing electric current through said element and adding heat to said body of molten aluminum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of adding heat to a body of aluminum contained in a heating bay, comprising the steps of:
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(a) providing a body of molten aluminum in a heating bay; (b) immersing an electric powered heater in said body of molten aluminum, said heater comprised of; (i) a tube having a closed end suitable for immersing in said molten aluminum, the tube comprised of an inner layer of titanium or titanium alloy having an outside surface having a refractory coating thereon exposed to and resistant to attack from said molten aluminum, said inner layer titanium or titanium alloy having a coefficient of expansion of less than 10×
10-6 in/in/°
F.;(ii) the refractory coating is selected from the group consisting of Al2 O3, ZrO2, Y2 O3 stabilized ZrO2, and Al2 O3 --TiO2, the refractory coating having a coefficient of expansion of less than 10×
10-6 in/in/°
F.; and(iii) an electric powered heating element located in said tube in heat transfer relationship therewith for adding heat to said molten aluminum; and (d) passing electric current through said element and adding heat to said body of molten aluminum. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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25. A method of adding heat to a body of aluminum contained in a heating bay, comprising the steps of:
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(a) providing a body of molten aluminum in a heating bay; (b) immersing an electric powered heater in said body of molten aluminum, said heater comprised of a tube of cast iron metal having an end suitable for immersing in said molten aluminum; (c) an electric powered heating element located in said tube in heat transfer relationship therewith for adding heat to said molten aluminum; and (d) passing electric current through said element and adding heat to said body of molten aluminum at a rate of 50 to 250 watts/in2.
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26. A recirculating method for heating or melting solid aluminum in molten aluminum, the method including the steps of:
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(a) circulating molten aluminum from a reservoir through at least one of a pumping bay, a heating bay, an aluminum metal charging bay and a treatment bay back to said reservoir; and (b) heating said molten aluminum in said heating bay with an electric heater providing heat to said molten aluminum at a watt density of 20 to 350 watts/in2, said heater comprised of a composite material having an inner layer of metal having a coefficient of thermal expansion less than 10×
10-6 in/in/°
F. and having an outer surface having a refractory coating thereon exposed to said molten aluminum and resistant to attack by said molten aluminum, said refractory coating having a coefficient of thermal expansion less than 10×
10-6 in/in/°
F. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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35. A recirculating method for heating or melting solid aluminum in molten aluminum, the method including the steps of:
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(a) circulating molten aluminum from a reservoir through a pumping bay, a heating bay, an aluminum metal charging bay and a treatment bay back to said reservoir; and (b) heating said molten aluminum in said heating bay with an electric heater providing heat to said molten aluminum at a watt density of 30 to 200 watts/in2, said heater comprised of a composite material having an inner layer of metal of titanium or titanium alloy having a coefficient of thermal expansion less than 5×
10-6 in/in/°
F. and having an outer surface having a refractory coating thereon exposed to said molten aluminum and resistant to attack by said molten aluminum, said refractory coating selected from the group consisting of one of Al2 O3, ZrO2, Y2 O3 stabilized ZrO2, and Al2 O3 --TiO2 having a coefficient of thermal expansion less than 5×
10-6 in/in/°
F.
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Specification