| 摘要 |
PURPOSE:To efficiently adjust the temp. drop of an aq. NaOH soln. in an anodizing etching vessel for an aluminum stock by positively circulating part of the above-mentioned aq. soln. to a cooler installed to the outside of the vessel. CONSTITUTION:The aluminum stock is subjected to a surface treatment by using the aq. NaOH soln. in the etching vessel 1 to remove the small surface defects from the stock as a pretreatment for the anodic oxidation treatment of aluminum. The exothermic effect by the reaction of the above-mentioned soln. in the vessel 1 and the aluminum stock is adjusted by positively circulating part of the aq. soln. by a pump 3 via a liquid path 2 to a heat exchanger 4 installed on the outside of the vessel 1 to cool the soln., by which the temp. thereof is decreased in the above-mentioned method. The Al(OH)3 settled in the heat exchanger 4 is detected by a differential pressure gage 5 andn washing water is passed through the heat exchanger from washing water inlet and outlet paths 6, 7 so that the deposited precipitate is surely removed in the stage of a slight amt. |
