膜式脱気法による建築設備配管の腐食防止に関する研究

概要

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We have studied on anti-corrosion for piping of building services by the vacuum membrane deairation system experimentally and prevented the reddish brown water in the hot and cold water supply pipes. The main contents that are clarified by these experiments are as follows. The corrosion rate of mild steel in deairated tap water with the dissolved oxygen concentration (DO) 0.5〜0.8mg/l decreased 1/3 less on average, 1/6 less on maximum as compared with in tap water. We have prevented the reddish brown water of hot water galvanized steel piping system and tap water lined steel piping system by lowering the DO to 0.5〜0.8mg/l. The pH of deairated tap water increased about 0.3〜0.4mg/l on deairated effect of deairation. The residual free chlorine, however, is high rate of soluble in water. Therefore, it doesn't matter from the viewpoint of sanitary index of the water quality. Generally, galvanic current of gun metal/mild steel decreased in comparison with in tap water, but didn't decrease so remarkably as lowering of corrosion rate of mild steel.
社団法人日本建築学会の論文
2001-01-30