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尽管人们对城市热网的设计、施工、运行已达到相当高的水平,但每年每百公里管道中仍有20—40%受到破坏。人们尚未找到一种可使地下热网免受腐蚀破坏的有效保温方法。热网腐蚀主要形式为点蚀。引起点蚀的原因很多,被水浸渍或被回填土覆盖的供水管道以及从无沟过渡到有沟管道的接合处极易发生点蚀。 地下采暖管道中热介质不断地随季节、时间变化,使环境温度也随之发生变化。这种运行条件对管道十分不利。与冷水管受蚀相比,采暖热管道由于金属处在较高温度下,
Although the design, construction and operation of urban heating networks have reached a fairly high level, 20 to 40% of the pipelines per 100 kilometers per year are still destroyed. People have not yet found an effective insulation method that can protect underground thermal networks from corrosion damage. The main form of thermal network corrosion is pitting. There are many causes of pitting corrosion. Pitting pits that are impregnated with water or covered with backfilled soil, as well as from joints without grooves to trenched pipes, are prone to pitting corrosion. The heating medium in underground heating pipes continuously changes with seasons and time, so that the ambient temperature also changes. This operating condition is very detrimental to the pipeline. Compared with cold water pipe erosion, the heating heat pipe due to the metal is at a higher temperature,