Process of forming enhanced heat transfer surfaces
First Claim
1. A process for enhancing the heat transfer properties of the surface of an aluminum alloy containing a pre-existing precipitate comprising subjecting said aluminum alloy to an etching composition for said precipitate for an effective period of time such that pits having an average size of from about 0.5 to 5 microns are formed in the surface, wherein prior to etching, the alloy is heating to a temperature sufficient to dissolve precipitates which, when subjected to said etching composition would form pits smaller than about 0.5 micron and quenched so that said precipitates do not reform, thereby minimizing the formation of pits smaller than about 0.5 micron.
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Accused Products
Abstract
Aluminum alloys suitable for fabrication into plate and fin type heat exchangers are subjected to a chemical etching procedure in order to improve the heat transfer efficiency thereof. Applicants have found that a high temperature heat treatment of an aluminum alloy plate material to produce a precipitate, followed by exposure to an etching composition, results in a heat exchanger surface modified by the formation of pits. The heat exchangers so modified may be advantageously used in the reboiler/condensor section of air separation units.
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Citations
8 Claims
- 1. A process for enhancing the heat transfer properties of the surface of an aluminum alloy containing a pre-existing precipitate comprising subjecting said aluminum alloy to an etching composition for said precipitate for an effective period of time such that pits having an average size of from about 0.5 to 5 microns are formed in the surface, wherein prior to etching, the alloy is heating to a temperature sufficient to dissolve precipitates which, when subjected to said etching composition would form pits smaller than about 0.5 micron and quenched so that said precipitates do not reform, thereby minimizing the formation of pits smaller than about 0.5 micron.
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