| 摘要 |
PURPOSE:To form a porous plated layer on the inner surface of a copper pipe by inserting an insoluble anode rod into the copper pipe with the inner surface coated with an hydrophobic thin film, and allowing a pulse current to flow between the copper pipe made negative and the anode rod while sending a copper plating soln. contg. gaseous N2 bubbles to carry out plating. CONSTITUTION:The thin film of a hydrophobic substance such as oil and paint is formed on the inner surface of the copper pipe 2 as the heat-transfer pipe to be used for a heat exchanger, and the insoluble anode 11 of Ti-Pt, etc., is arranged at the center part. A copper plating soln. contg. copper sulfate from a plating soln. tank 1 is passed by a pump 7 through a filter 8, a flowmeter 9, and the heat-transfer pipe 2, and again recovered in the tank 1. At this time, gaseous N2 from a cylinder 14 is mixed into the plating soln. in the form of bubbles and supplied to the heat-transfer pipe 2, a pulse current is allowed to flow between the heat-transfer pipe 2 and the electrode 11 by the power source 12, and a porous copper plated layer is formed on the inner surface of the heat-transfer pipe 2 on which N2 bubbles are deposited. A heat-transfer pipe for a heat exchanger having excellent heat exchange efficiency is thus obtained. |
