Heat exchanger assembly with magnesium barrier
First Claim
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1. An improved heat exchanger assembly comprising:
- at least one aluminum based tube including magnesium adapted to be exposed to an ambient atmosphere and having an internal surface and an external surface;
an aluminum based cladding disposed adjacent one of the internal and external surfaces;
at least one aluminum based component disposed adjacent the cladding;
a brazing flux applicable between the aluminum based cladding and the aluminum based component to facilitate brazing in the ambient atmosphere; and
an aluminum based lithium enriched layer disposed between the one of the internal and external surfaces and the aluminum based cladding;
whereby the aluminum based lithium enriched layer is adapted to scavenge sufficient oxygen from the ambient atmosphere during brazing to form a sufficient barrier against the diffusion of magnesium from the aluminum based tube that the formation of undesirable magnesium oxide is resisted.
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Abstract
The invention involves a heat exchanger assembly comprising at least one aluminum based tube including magnesium, an aluminum based cladding, and at least one aluminum based component disposed adjacent the cladding. A brazing flux is applied to a joint between the cladding and the component to facilitate brazing in an ambient atmosphere. An aluminum based lithium enriched layer is disposed between the tube and the cladding to scavenge sufficient oxygen from the ambient atmosphere to form an effective barrier against the defusion of magnesium from the tube.
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Citations
15 Claims
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1. An improved heat exchanger assembly comprising:
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at least one aluminum based tube including magnesium adapted to be exposed to an ambient atmosphere and having an internal surface and an external surface;
an aluminum based cladding disposed adjacent one of the internal and external surfaces;
at least one aluminum based component disposed adjacent the cladding;
a brazing flux applicable between the aluminum based cladding and the aluminum based component to facilitate brazing in the ambient atmosphere; and
an aluminum based lithium enriched layer disposed between the one of the internal and external surfaces and the aluminum based cladding;
whereby the aluminum based lithium enriched layer is adapted to scavenge sufficient oxygen from the ambient atmosphere during brazing to form a sufficient barrier against the diffusion of magnesium from the aluminum based tube that the formation of undesirable magnesium oxide is resisted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
a turbulator disposed adjacent the cladding on the internal surface, and a fin disposed adjacent the cladding on the external surface.
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8. The heat exchanger assembly of claim 1 wherein the at least one aluminum based component comprises material of the Aluminum Association 3XXX series aluminum alloys.
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9. The heat exchanger assembly of claim 1 wherein the lithium in the aluminum based lithium enriched layer ranges from about 0.1 percent to about 9.9 percent by weight based on the weight of the aluminum based lithium enriched layer.
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10. A method of manufacturing an improved heat exchanger assembly for an automotive vehicle, the method comprising:
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providing at least one aluminum based tube including magnesium adapted to be exposed to an ambient atmosphere and having an internal surface and an external surface;
applying an aluminum based lithium-enriched layer to at least one of the internal and external surfaces;
applying an aluminum based cladding to the aluminum based lithium enriched layer;
disposing at least one aluminum based component adjacent the cladding;
applying a brazing flux to a joint between the cladding and the at least one aluminum based component to facilitate brazing in the ambient atmosphere; and
joining the at least one tube and the at least one aluminum based component together in the ambient atmosphere using a controlled atmosphere brazing process. - View Dependent Claims (11, 12, 13, 14, 15)
a turbulator disposed adjacent the cladding on the internal surface, and a fin disposed adjacent the cladding on the external surface.
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14. The method of claim 10 wherein the at least one aluminum based component comprises material of the Aluminum Association 3XXX series aluminum alloys.
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15. The method of claim 10 wherein the aluminum based lithium enriched layer includes lithium ranging from about 0.1 percent to about 9.9 percent by weight based on the weight of the aluminum based lithium enriched layer.
Specification