冷凝式燃气热水器换热器低温段防腐试验研究

对4台冷凝式热水器进行了1 200 h耐久试验,在其中3台的换热器低温段的铜肋片管表面采用3种有机防腐涂料,另外1台不使用任何防腐涂料,进行对比试验.干粉环氧树脂的耐温与抗酸腐蚀性可以满足使用要求,但还需改进喷涂工艺以提高粘附力.分析了燃用天然气时出现的严重酸性腐蚀现象,结合换热器温度测量结果,探讨了换热器冷凝腐蚀的原因,以及冷凝水和腐蚀污染物的生成条件.研究了冷水温度和防腐涂层对热水器热效率的影响.

Experimental Study on Corrosion Prevention of Low-temperature Section of Heat Exchanger in Condensing Gas Water Heater

The 1 200 h endurance test for four condensing gas water heaters is performed. Three of them have three kinds of organic anticorrosive coatings on the surface of copper fin tube of low-temperature section of heat exchanger, one of them has no any coating, and a comparative experiment is carried out. The temperature resistance and acid corrosion prevention of dry-power epoxy resin can meet the operation requirement, but the spraying technology still needs to be improved to increase the adhesion. The serious acid corrosion occurred in the case of burning natural gas is analyzed. Combined with the heat exchanger temperature measurement results, the causes of condensing corrosion of the heat exchanger and the forming conditions of condensate and corrosive pollutants are discussed. The influence of cold water temperature and anticorrosive coating on the thermal efficiency of water heater is studied.