| 摘要 |
The internal wall of a heat exchange panel, formed by inflating roll-bonded aluminium sheets to form a tube circuit, is protected against corrosion by coating it with a thin film of protective varnish. The coating process pref. comprises (a) completely filling the circuit with varnish, by means of a pump connected to one or more circuit openings at the bottom of the panel, and emptying the circuit; (b) closing the circuit opening(s) at the top of the panel and subjecting the circuit to a reduced pressure of the varnish solvent at ambient temp.; and (c) draining the circuit and heating the panel to evaporate the solvent and cure the varnish film. The method is esp. useful for protecting solar energy absorbers against corrosion by the internally circulating fluid which may be tap water, an industrial fluid, saline water for pure water prodn. or chlorinated water e.g. for swimming baths. The protected panel can be used for direct heating ofsuch fluids thus avoiding the requirement for secondary circuit, special heat transfer fluids, etc. |
