Electric heating element and heater assembly
OwnerC. Edward Eckertinventor
Life of this patent
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Abstract
Disclosed is an improved electric heater assembly suitable for heating molten metal, the electric heater assembly having a sleeve comprised of a closed end suitable for immersing in the molten metal. The sleeve is fabricated from a composite material comprised of titanium alloy and having an outside surface to be exposed to the molten metal coated with a refractory resistant to attack by the molten metal; and an electric heater located in the sleeve in heat transfer relationship therewith.
Claims29
An electric heater assembly for heating molten metal, the electric heater assembly comprised of:
- (a) a sleeve suitable for immersing in said molten metal, the sleeve comprised of:
- (i) a base metal layer having a coefficient of thermal expansion of less than 10.times.10.sup.31 6 in/in/.degree. F.;
- (ii) an outside surface to be exposed to said molten metal coated with a refractory resistant to attack by said molten metal, the refractory having a coefficient of thermal expansion of less than 10.times.10.sup.-6 in/in/.degree. F.;
- and
- (iii) a bond coat located between said base metal layer and said refractory:
- (b) an electric heating element located in said sleeve in heat transfer relationship therewith for adding heat to said molten metal, the electric heating element comprised of titanium or titanium alloy;
- and
- (c) a powdered contact medium in said sleeve for improved conduction of heat from said element to said sleeve.
An electric heater assembly suitable for heating molten metal, the electric heater assembly comprised of a sleeve suitable for immersing in said molten metal, the sleeve fabricated from a composite material comprised of:
- (a) a base metal layer having a coefficient of thermal expansion of less than 10.times.10.sup.-6 in/in/.degree. F.;
- (b) a bond coat bonded to an outside surface of said base layer to coat said surface to be exposed to said molten metal;
- (c) a refractory coating bonded to said bond coat, the refractory layer resistant to attack by said molten metal and having a coefficient of thermal expansion of less than 10.times.10.sup.-6 in/in/.degree. F.;
- (d) an electric heating element located in said sleeve in heat transfer relationship therewith for adding heat to said molten metal, the electric heating element comprised of titanium or titanium alloy having the ability to form a coherent oxide of titanium therein;
- and
- (e) a powdered contact medium in said sleeve for improved conduction of heat from said element to said sleeve.
An electric heater assembly suitable for heating molten metal, the electric heater assembly comprised of a sleeve having a closed end suitable for immersing in said molten metal, the sleeve fabricated from a composite material comprised of:
- (a) a base metal layer of a titanium alloy selected from alpha, beta, near alpha, and alpha-beta titanium alloys;
- (b) a bond coat bonded to an outside surface of said base layer to coat said surface to be exposed to said molten metal;
- (c) a refractory layer bonded to said bond coat, the refractory layer resistant to attack by said molten metal;
- and
- (d) an electric heating element located in said sleeve in heat transfer relationship therewith for adding heat to said molten metal, said heating element comprised of titanium or titanium alloy.
An electric heater assembly suitable for heating molten metal, the electric heater assembly comprised of a sleeve having a closed end suitable for immersing in said molten metal, the sleeve fabricated from a composite material comprised of:
- (a) a base layer of a titanium or titanium alloy;
- (b) a bond coat bonded to an outside surface of said sleeve;
- (c) a refractory layer selected from a material comprising Al.sub.2 O.sub.3, ZrO.sub.2, Y.sub.2 O.sub.3 stabilized ZrO.sub.2, and Al.sub.2 O.sub.3 --TiO.sub.2 bonded to said bond coat, the refractory layer resistant to attack by said molten metal;
- (d) an electrical heating element located in said sleeve in heat transfer relationship therewith for adding heat to the molten metal, said heating element comprised of titanium or titanium having a layer of oxide on the surface thereof;
- and
- (e) a powdered contact medium in said sleeve to improve heat transfer from said heating element to said sleeve, the heater assembly capable of operating at a watt density in the range of 25 to 250 watts/in.sup.2.
Dependencies are inferred from the claim text.