浅谈球墨铸铁管的性能与安装

本文主要简单介绍了球管的管材结构、性质，并通过与普通灰口铸铁管的一些性能比较，显示了球管作为供水管道所具有的优越性，进而探讨了球管在供水安装一系列环节中所应注意的一些问题。     

穿插高密度聚乙烯管修复技术在广州的应用

近几年穿插HDPE管修复旧管道新型技术在国内供水行业中正逐步推广应用。为改善供水管道水质,广州市自来水公司对位于海珠区赤沙路1984、1988年敷设且没有进行内衬水泥砂浆的原DN400灰口铸铁管,采用“等径压缩”及“U型压缩”法穿插HDPE管修复技术进行施工试验。现将施工试验结果介绍如下：     

玻璃钢夹砂管与铸铁管、预应力混凝土管技术分析及其发展前景

在市政供水和污水工程中,选择合适的管材对工程质量、造价及效益有着极大的影响.玻璃钢夹砂压力管道作为一种新型工程管材,在技术性能与灰口铸铁管、预应力混凝土管相比具有很大的优势,现对这三种管道进行分析.     

供水管网的管材选择

由于历史条件的限制,在二十世纪九十年代前,我国的供水管道以灰口铸铁管、镀锌管和水泥管为主。由于铸铁管和镀锌管在材质和防腐方面都存在问题,以至于管材的使用寿命短,对水质造成的二次污染严重。为推广新型管材,建设部等五部分别于1995年和1997年联合发布了《关于加强我国化学建材生产和推广应用的若干意见》、建科[1997]154号文件《国家化学建材推广应用“九五”计划和2010年发展规划纲要》,     

浅析球墨铸铁管与灰口铸铁管

本文从材质、生产工艺、机械性能、施工、安装、经济价格等方面对比分析了球墨铸铁管和灰口铸铁管，结合八钢地区供水管爆管管材的情况，提出球墨铸铁管优于灰口铸铁管，为管材的设计选型提供了新的依据。     

《给水排水管道工程施工及验收规范》讲座：第（3）讲 铸铁,球墨铸铁管安装

3 铸铁、球墨铸铁管安装3.1 铸铁、球墨铸铁管应用现状 铸铁、球墨铸铁管按材质可分为灰口铸铁管和延性铸铁管。前者属刚性管,后者属柔性管,灰口铸铁管又称普通铸铁管,其生产工艺有离心铸铁管和连续铸铁管两种。灰口铸铁接口属刚性口,需用石棉水泥填打,劳动强度高,工期长且受气候的干扰,影响施工进度。由于该种管材料源充足,规格齐全,管件     

改造燃气管网 保障供气安全

<正>燃气安全关系到全市人民群众切身利益,目前,邹城市存在的燃气安全隐患主要是灰口铸铁管。为切实消除安全隐患,邹城市在2014年完成33km改造的基础上,2015年,邹城市委、市政府把剩余49.75km灰口铸铁管改造列为2015年"百项重点工程"。计划6月底前完成38条道路管道改造,9月底     

关于在煤气管网中大规模使用PE管的探讨

大连地区煤气管网已经有近百年的历史,在这近百年的发展历程当中,煤气管网的管材也随着材料科学的进步,得到了一次次的更新换代,由当初的灰口铸铁管、铅口铸铁管、压兰铸铁管、球墨铸铁管到目前普遍使用的钢管,以及属国际先进水平的PE(聚乙烯)管。 PE管是大连煤气公司管道工程处近几年开始采用的新型管材,我们在施工过程中发现,该种材料具有诸多优点。     

室内下水铸铁管产生裂口的原因极其修复、预防措施

1　铸铁管产生裂口的原因下水铸铁管产生裂口主要是由用户在冬季突然排放高温热水所致。2　对铸铁管裂口的修复①　局部更换法。先用焊机把裂口管段拆除 ,然后换上新管重新打灰口 (2 4ｈ内不得用水 )。经该法修复后管道完好如初 ,但拆装麻烦、修复费用高 ,且修复时影响正常使用。它主要适用于靠近自由端的裂口管段的修复。②　套袖水泥打口法。首先根据裂口管段的尺寸截取一段钢管 ,沿管的纵向劈成两片 ,将其套在裂口管段处并用焊机把两片再焊接起来 (做成承口状套袖 ) ,然后向套袖与铸管间的间隙内填灰 ,打灰口。该法主要适用于不易拆装的…     

环氧树脂喷涂修复对供水管网节点压力的影响

城市供水管网在运行一段时间后,铸铁管会出现锈蚀的问题,这会减小管道过水断面面积和增加管道摩阻系数,从而提高了供水能耗。环氧树脂喷涂改造是一种新型的管道修复方法,依托北京某小区供水管网喷涂改造修复工程,研究了喷涂前后管网监测点压力值的变化情况,结果表明喷涂改造后管网监测点压力值都有所上升。     

Chlorine decay in drinking-water transmission and distribution systems: pipe service age effect

Water quality can deteriorate in the transmission and distribution system beyond the treatment plant. Minimizing the potential for biological regrowth can be attained by chlorinating the finished water. While flowing through pipes, the chlorine concentration decreases for different reasons. Reaction with the pipe material itself and the reaction with both the biofilm and tubercles formed on the pipe wall are known as pipe wall demand, which may vary with pipe parameters. The aim of this paper was to assess the impact of the service age of pipes on the effective chlorine wall decay constant. Three hundred and two pipe sections of different sizes and eight different pipe materials were collected and tested for their chlorine first-order wall decay constants. The results showed that pipe service age was an important factor that must not be ignored in some pipes such as cast iron, steel, cement-lined ductile iron (CLDI), and cement-lined cast iron (CLCI) pipes especially when the bulk decay is not significant relative to the wall decay. For the range of the 55 years of pipe service age used in this study, effective wall decay constants ranged from a decrease by -92% to an increase by +431% from the corresponding values in the recently installed pipes. The effect of service age on the effective wall decay constants was most evident in cast iron pipes, whereas steel pipes were less affected. Effective chlorine wall decay for CLCI and CLDI pipes was less affected by service age as compared to steel and cast iron pipes. Chlorine wall decay constants for PVC, uPVC, and polyethylene pipes were affected negatively by pipe service age and such effect was relatively small.     

Experimental evaluation of bursting capacity of corroded grey cast iron water pipeline

Cast iron was used in the water industry prior to 1970 and a large number of cast iron pipes still remain as trunk mains. These pipes have been subjected to different levels of corrosion and variety of loading conditions. This leads cast iron pipes to fail in the field without prior warning. Water utilities are seeking solutions to optimise cast iron pipe renewal and rehabilitation programs for critical water mains (diameter ≥ 300 mm). A new experimental set-up has been developed at Monash University in order to perform burst testing of large diameter cast iron pipes (diameter ≥ 300 mm). A section of cast iron pipe, extracted during maintenance in Sydney, was laser scanned to determine the remaining thickness of the pipe (minimum of 7–8 mm at the most critical patches). Although the pipe was pressurised to 3.6 MPa, catastrophic failure did not occur. Water leakage from the two critically corroded patches was observed at around 3.25–3.45 MPa internal pressure. Strain results on the outer pipe surface were greater than the strain measured during tensile testing of the same pipe material. A 3-D finite element model using the scanned pipe dimensions was able to predict the maximum pressure at pipe failure (~3.7 MPa) within the range of leaking water pressure level observed in the experiment.     

Structural integrity of corrosion-affected cast iron water pipes using a reliability-based stochastic analysis method

A significant proportion of current water networks are composed of cast iron pipes. The occurrence of failures of this type of pipe is increasing due to ageing and progressive deterioration (i.e. corrosion). This necessitates the completion of structural integrity assessment and reliability analysis of in-service cast iron water pipes. The failure of a cast iron pipe can be characterised by fracture, when the stress intensity factor exceeds the toughness of the pipe material. In this research, a stochastic model for the stress intensity factor is developed and a time-dependent analysis method is employed to quantify the failure probability so that the time for the pipe to be failed and, hence, requiring repairs or replacement is determined with confidence. For a comprehensive structural assessment, two types of stresses (hoop and axial) are considered for two cases of corrosion (external and internal). A case study is provided to illustrate the application of the proposed method. In the system failure analysis, it is found that hoop stress is the dominant stress, since it can result in external corrosion, the effects of which are known to be of greater significance than those caused by internal corrosion.     

Iron release from corroded iron pipes in drinking water distribution systems: effect of dissolved oxygen

Iron release from corroded iron pipes is the principal cause of "colored water" problems in drinking water distribution systems. The corrosion scales present in corroded iron pipes restrict the flow of water, and can also deteriorate the water quality. This research was focused on understanding the effect of dissolved oxygen (DO), a key water quality parameter, on iron release from the old corroded iron pipes. Corrosion scales from 70-year-old galvanized iron pipe were characterized as porous deposits of Fe(III) phases (goethite (alpha-FeOOH), magnetite (Fe(3)O(4)), and maghemite (alpha-Fe(2)O(3))) with a shell-like, dense layer near the top of the scales. High concentrations of readily soluble Fe(II) content was present inside the scales. Iron release from these corroded pipes was investigated for both flow and stagnant water conditions. Our studies confirmed that iron was released to bulk water primarily in the ferrous form. When DO was present in water, higher amounts of iron release was observed during stagnation in comparison to flowing water conditions. Additionally, it was found that increasing the DO concentration in water during stagnation reduced the amount of iron release. Our studies substantiate that increasing the concentration of oxidants in water and maintaining flowing conditions can reduce the amount of iron release from corroded iron pipes. Based on our studies, it is proposed that iron is released from corroded iron pipes by dissolution of corrosion scales, and that the microstructure and composition of corrosion scales are important parameters that can influence the amount of iron released from such systems.     

浅议给排水设计中管材的选取与运用

分别介绍了管道工程中钢管、铸铁管、塑料管、复合管材等常用管材的特点,适用范围及连接方法,总结归纳了给排水工程中选择管材时应考虑的各种因素,以指导设计人员正确选取管材,使整个系统性价比最高。     

Some effects of aqueous silica on the corrosion of iron

Silica is an important natural component of ground and surface waters, and is sometimes added as an inhibitor to control "red water" problems caused by corroding iron pipes. However, the effect of silicates on many aspects of iron corrosion has never been assessed. Experiments with water containing 0.5, 10, 25 or 50mg/L of SiO(2) demonstrated a significant interplay between aqueous silica and iron corrosion. During this 4-month experiment, higher levels of silica caused more iron release to the water and decreased the size of suspended iron particles. The process of iron corrosion also changed aqueous silica concentrations; silica was released into the water from the cast iron during corrosion and was removed from the water by incorporation into the scale layer. Silica also affected the type of scale that formed on the iron coupons. Scale at the lower silica concentrations was fairly uniform and easy to remove from the coupons, while the scale from the high silica reactors was more dense, and was more difficult to remove. Scale from the high concentration silica reactor also developed tall tubercles, and hydrogen gas-containing bubbles were channeled to solution through these tubercles. Iron corrosion occurring via the evolution was significant under all experimental conditions.     

地铁隧道区间内球墨铸铁管的加固措施

对球墨铸铁管在地铁隧道区间应用的优、缺点进行了分析,并针对其缺点提出了合理的解决措施,以保证供水安全、可靠。     

再生水管道管材的经济技术比较

根据实践经验,对球墨铸铁管、钢塑复合钢管及PE给水管进行了管道水头损失及管材费用、防腐性能、物理性能等方面的比较,通过对比研究,得出钢塑复合钢管用于再生管道工程中具有较好的防腐、节能效果,值得推广应用。     

球墨铸铁管在燃气工程中的应用

通过分析球墨铸铁性质，结合广州市的特性，探讨离心球墨铸铁管在广州市燃气工程中得到广泛的应用问题。     

Introduction of the leak-before-break (LBB) concept for cast iron water pipes on the basis of laboratory experiments

Failure of cast iron water mains in Australia is a common occurrence. Water utilities are seeking solutions to optimise the renewal and rehabilitation of ageing cast iron critical water mains (diameter ≥ 300 mm). Failure pressures of three large-diameter cast iron pipe specimens (600 mm in diameter) were tested. A large corrosion patch was machined onto each pipe section to initiate pipe failure. A large corrosion patch and significant reduction (>90%) of pipe wall thickness were needed to fail the tested pipe specimens. All three pipes under test exhibited leaking before bursting, indicating that the concept of leak-before-break (LBB) could be used for pipe failure prevention. In addition, LBB provides valuable information that could be added to the pipe asset database to make better management decisions on repair or replacement along with all other asset information. The study also found that small corrosion patches (<50 mm) with low remaining wall thickness may cause pipe leaks, but are less likely to cause major pipe bursts.