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城市地下埋有自来水、煤气管、输油气管道、电缆等设施,且土壤中杂散电流又很强,因此城市中地下金属设施的阳极保护大多采用牺牲阳极保护,这是因为阳极具有施工灵活,管理简单等特点,对邻近设施无干扰腐蚀。一、埋地管线牺牲阳极保护设计工程中常用测量土壤电阻率来判断土壤腐蚀性的级别。土壤电阻率是综合性的指标,且与阳极的输出电流及选用何种阳极材料都有直接的关系。沿管道走向定点测量土壤电阻率,平均每1公里左右一个测试点,同时还了解管道沿线有无杂散电流源等情况。 1.保护电流密度为了使金属达到完全保护,必须正确选取阴极保护电流密度,如果选取的电流密度偏低,金属达不到完全保护;反之,将会造成不必要的经济损失。
Cities have buried underground water, gas pipes, oil and gas pipelines, cables and other facilities underground, and the stray currents in the soil are very strong. Therefore, the anode protection of underground metal facilities in cities mostly uses sacrificial anode protection. This is because the anode has a flexible construction. Features such as simple management, no interference with adjacent facilities. First, buried pipeline sacrificial anode protection design engineering commonly used to measure the soil resistivity to determine the level of soil erosion. Soil resistivity is a comprehensive indicator and has a direct relationship with the output current of the anode and what anode material is chosen. The soil resistivity was measured along the direction of the pipeline, with an average of one test point per kilometer, and the presence of stray current sources along the pipeline was also known. 1. Current density protection In order to fully protect the metal, the cathodic protection current density must be correctly selected. If the current density selected is low, the metal will not be fully protected; otherwise, it will cause unnecessary economic losses.