Water hammer protection for diversion systems in front of pumps in long-distance water supply projects

For a water supply system with long-distance diversion pipelines, in addition to the water hammer problems that occur beyond pumps, the safety of the water diversion pipeline in front of pumps also deserves attention. In this study, a water hammer protection scheme combined with an overflow surge tank and a regulating valve was developed. A mathematical model of the overflow surge tank was developed, and an analytical formula for the height of the overflow surge tank was derived. Furthermore, a practical water supply project was used to evaluate the feasibility of the combined protection scheme and analyze the sensitivity of valve regulation rules. The results showed that the combined protection scheme effectively reduced the height of the surge tank, lessened the difficulties related to construction, and reduced the necessary financial investment for the project. The two-stage closing rule articulated as fast first and then slow could minimize the overflow volume of the surge tank when the power failure occurred, while the two-stage opening rule articulated as slow first and then fast could be more conducive to the safety of the water supply system when the pump started up.

Detection of Water Meter Digits Based on Improved Faster R-CNN

In order to more accurately detect the accuracy of word-wheel water meter digits, 2000 water meter pictures were produced, and an improved Faster-RCNN algorithm for detecting water meter digits was proposed. The improved Faster-RCNN algorithm uses ResNet50 combined with FPN (Feature Pyramid Network) structure instead of the original ResNet50 as the feature extraction network, which can enhance the accuracy of the model for small-sized digit recognition;the use of ROI Align instead of ROI Pooling can eliminate the error caused by the quantization process of the ROI Pooling twice, so that the candidate region is more accurately mapped to the feature map, and the accuracy of the model is further enhanced. The experiment proves that the improved Faster-RCNN algorithm can reach 91.8% recognition accuracy on the test set of homemade dataset, which meets the accuracy requirements of automatic meter reading technology for water meter digital recognition, which is of great significance for solving the problem of automatic meter reading of mechanical water meters and promoting the intelligent development of water meters.

Study on the Technology of Supplying Water Safely by Long-Distance Pipeline

The extensively built long-distance water transmission pipelines have become the main water sources for urban areas. To ensure the reliability and safety of the water supply, from the viewpoint of overall management, it would be necessary to establish a system of information management for the pipeline. The monitoring, calculating and analyzing functions of the system serve to give controlling instructions and safe operating rules to the automatic equipment and technician, making sure the resistance coefficient distribution along the pipeline is reasonable; the hydraulic state transition is smooth when operating conditions change or water supply accidents occur, avoiding the damage of water hammer. This paper covered the composition structures of the information management system of long-distance water transmission pipelines and the functions of the subsystems, and finally elaborated on the approaches and steps of building a mathematics model for the analysis of dynamic hydraulic status.

Magnetized Water and Memory Meter

This paper presents an experimental study to investigate the effect of using the magnetic water conditioner on the properties of water. The water flows through a closed loop, while the pH, TDS, and hardness represent its properties. For magnetic water conditioner with flux density of 170 mT, results showed that pH increased by 15.65% for 820 minutes of non-stop circulation. The increase in pH is divided to 93.5% for the first 360 minutes, and 6.5% for the last 460 minutes. TDS and Hardness of water are not affected by the magnetic water conditioner. Water remembers and keeps the impact of passing through the magnetic field for several hours, and pH decreased by 0.642 in24 hours. While the results lead to introduce and create the magnetized water saturation curve and water memory meter.

Partitioning of Water Distribution Network into District Metered Areas Using Existing Valves

Water distribution network(WDN)leakage management has received increased attention in recent years.One of the most successful leakage-control strategies is to divide the network into District Metered Areas(DMAs).As a multi-staged technique,the generation of DMAs is a difficult task in design and implementation(i.e.,clustering,sectorization,and performance evaluation).Previous studies on DMAs implementation did not consider the potential use of existing valves in achieving the objective.In this work,a methodology is proposed for detecting clusters and reducing the cost of additional valves and DMA sectorization by considering existing valves as much as possible.The procedure of DMAs identification has been divided into three stages,i.e.,a)clusters identification;b)sectorization or boundaries optimization and c)performance evaluation of the partitioned network.The proposed methodology is evaluated on a simple network and a real-world water network with the findings provided and compared to the DMAs,established for a raw water network with no existing valves.It is found that there is an adequate difference in cost of strategy implementation in both the cases for the network under consideration and the existing valve system achieved better network performance in terms of resilience index.

Rapid Sample Product Trial Manufacture Technique for Developing Water Meter New Products

This paper advances the viewpoints and methods of the rapid sample product trial manufacture technique for developing water meter new products by CAD and simulation, computer virtual assembling and optimizing, rapid machining process and measurement etc. as the design and sample product trial manufacture process of water meter new products are long in product development period, and low in product development efficiency in the present time.

智能水表多场景应用综合测试评估研究

水表是城市供水系统的核心计量设备和信息数据源,对于提高精细化管理水平,缩小产销差至关重要。通过试验比较了机械式水表和智能水表的计量精度,从数据精确度、数据上传率和电池续航力等方面对智能水表性能进行综合测评,结合智能水表在分区计量、水费自动结算、漏损预警、老年人居家安全监测等多场景应用实例,展示了智能水表在智慧水务建设中的推广应用价值。在低流量范围,智能水表的计量精度明显优于机械水表;智能水表以其高精度计量、实时数据传输和智能化管理等特点,更符合超大型城市漏损控制智慧数据监测的应用趋势。

考虑压力均匀性的供水管网独立计量区域(DMA)分区优化研究

独立计量区域(district meteredareas,DMAs)是实现城市供水管网压力管理与漏损控制的重要手段。现有的DMA分区算法无法在分区时保障分区内部的压力均衡。为解决这一问题,本文提出一种基于迭代求解DMA分区方法,在保证分区均匀性的同时,实现分区内部压力均衡。该方法提出融合节点压力分布的节点相似矩阵,建立分区合理性评价指标,用于确定独立计量区域划分方案;在隔离阶段采用改进的多目标遗传算法,对边界管段开展隔离阀与流量计的优化布置;最后通过对上述2个过程进行循环迭代,确保最终分区方案的压力均衡。通过对实例管网的分区研究,验证改进方法的有效性和可行性。

基于CAE的智能水表盖注塑模具设计

结合智能水表复杂结构特征,基于CAE软件对其进行注塑模具设计。通过Moldflow模流分析确定最佳的浇口位置,设计了浇注系统和冷却系统,并通过冷却+填充+保压+翘曲分析验证浇注系统和冷却系统设计的合理性;针对复杂结构特征,基于UG,通过设计斜顶+推杆机构实现侧凹成型,通过设计直顶+斜顶机构实现侧孔成型,通过设计滑块+弹簧的侧向抽芯机构实现侧凸成型。模具结构合理,动作可靠,可为同类设计提供参考。

温度对投入式水位计测量精度的影响研究

小沙湾水厂是黄河地表水给水工程的重要组成部分,是准能集团的重要水源地,而精准的水位数据对泵站取水工作有较大的影响。以浮子式水位计示值为参照,设计了投入式水位计示值的对比试验,对影响传感器精度的主要因素之一温度进行了研究,总结了温度与示值误差之间的关系。结果发现,在10~18℃时,水温对传感器精度影响很小;在18~25℃时,水温越高传感器精度越低;在26~30℃时,传感器精度随温度升高而升高。

基于改进YOLOv5s的指针式水表读数检测

针对光照不均匀和水表表盘雾化的指针式水表在读数检测时出现漏检、误检等问题,提出一种基于改进YOLOv5s的指针式水表读数检测方法。首先,采用Mosaic、Mixup等数据增强方法,提高模型的泛化能力;其次,引入加权双向特征金字塔网络(bilateral feature pyramid network, BiFPN)实现更高层次的特征融合使得水表图像的深层特征图和浅层特征图充分融合,提高网络的表达能力;然后,嵌入卷积注意力机制(convolutional block attention module, CBAM),在通道和空间双重维度上强化指针式水表子表盘示数特征;最后将完全交并比损失函数(complete intersection over union loss, CIoU-Loss)替换为SIoU_Loss(scylla intersection over union loss),提升边界框的回归精度。改进算法的mAP@0.5达到97.8%,比YOLOv5s原始网络提升了3.2%。实验结果表明:该算法能有效提高指针式水表的读数检测精度。

基于深度学习的水管式沉降仪数据采集方法

传统水管式沉降仪主要通过压力传感器来测量水位进而计算坝体内部沉降量,其存在测量稳定性差的问题。针对此弊端,提出一种基于深度学习的水管式沉降仪数据采集方法,包含特制水尺及相应算法。通过摄像机从上至下分段拍摄特制水尺并筛选出水位所在图像;采用二维码标识对图像进行角度校正并切割出水尺及测量管区域,同时读取厘米级水位坐标;基于UNet搭建图像抠图模型精确分割测量管中水位;最后结合水位线坐标,采用YOLOv5模型识别标尺毫米级坐标。试验结果表明,该技术环境适应性强,测量结果与人工读值相比,其误差均小于0.3 mm,满足实际工程的需要。

低含水油水两相流等效介电常数模型

电容法测油水两相流含水率在油田的地面油水计量及井中的产出剖面分层测试中都得到广泛应用。持水率(水相体积分数)的测量需要建立油水两相流持水率与传感器电容的关系,为此需要建立混相等效介电常数与持水率的理论模型或经验模型。由于油井采出的地层水以及地面实验室标定所用的自来水在低频和中频时均具有良好导电性,因此,单纯考虑介电性而不考虑导电性会对持水率测量的准确性产生显著影响。基于电介质极化的有效电场理论,在低含水且油水状态为精细泡状流条件下,将水视为良导体,建立了油水两相流等效介电常数模型。按此模型,油水两相流的等效介电常数只取决于持水率和油相介电常数,与水相介电常数以及水相电导率无关,初步实验验证了模型正确。该研究对于油为连续相时油水两相流的含水率传感器的设计和现场应用具有重要意义。

华北平原城市供水漏损控制策略案例

华北平原城市普遍存在水资源短缺问题,成为制约城市发展的重要因素,城市公共供水管网漏损控制是城市节水的重要内容。研究以A市为例开展华北平原城市供水漏损控制策略案例研究,提出了一套基于供水水量平衡分析与漏损控制潜力预测的漏损控制目标制定方法,并结合华北平原城市供水系统特点制定一套漏损控制系统方案,并重点介绍了A市分区计量管理建设与运维方案。研究结果表明,华北平原城市可从摸清家底、更新设施、调控压力、提升计量、引智赋能、完善机制6个方面开展城市公共供水管网漏损控制工作,对于以小区管网漏损为主的城市应采取自下而上的分区计量建设路线,并完善分区计量平台、建立管理体制、规范工作流程。研究可为同类城市开展城市公共供水管网漏损控制工作提供指导。

相关式油井液相计量系统研究与设计

针对现有油井计量方式自动化程度低,误差较大等问题,利用同轴线相位法含水率计设计了一种相关式油井液相计量系统,该系统以同轴线相位法含水率计为传感器构建了相关流量计,基于互相关法建立了计量模型,实现了流量与含水率的同步测量。通过对不同情况下上、下游含水率计信号的分析可知,两路信号之间具有相关性,满足相关流量计的使用条件。该系统在现场试验的测量结果与涡轮流量计相比,平均误差为11.36%。试验结果证明了相关式油井液相计量系统在实际应用中的可行性。

供水管网漏损控制方法与应用成效分析

随着经济社会发展,城镇化进程加快,水资源供需矛盾短缺日趋严重,而城市供水管网漏损,是目前困扰节水的难题之一,供水管网漏损控制已成为“十四五”城市供水行业的重点工作之一。文章简要介绍了供水管网漏损的原因和主要控制方法。重点结合水司自身特点,分析了实际工程应用成效,主要包括:推进独立计量区(DMA)进行的夜间最小流量监控;开展日常巡检及周期性检漏;定期开展水表轮换;改造老旧管网;布设管网压力监测点;加装水池水箱远程监控。而通过各种不同控制手段的结合使用,有效地控制了管网漏损,2023年综合漏损率降低为10%,研究成果以期为各水司供水管网的漏损控制提供指导和借鉴。

水表检定的台位差和表位差现象分析

根据测量理论,由于真值不可得,测量误差是不可消除的,两组测量结果之间存在差异不可避免。水表检定过程中产生台位差和表位差是不可避免的,台位差和表位差主要是两组不同测量所对应的测量设备、测量方法以及各种显性的和隐性的测量条件存在一定的差异所致。分析台位差和表位差是否具有显著性,需要确定一个合理的用于判定测量结果一致性的准则,然后再根据实验过程来分析查找导致不合理偏差产生的原因。当测量结果比较表明存在显著的台位差或表位差时,应结合经验进行具体的成因分析,并采取措施加以消除。

基于LabVIEW的油井多相流相关流量计量系统

油井产量计量是油田开发过程中的一项重要工作。针对当前计量方式自动化程度低、实时性差等问题,基于相关流量计理论,以同轴线相位法含水率计为测量传感器,设计了一种油井多相流相关流量计量系统,并基于LabVIEW建立了数据采集计量系统,实现了流量的实时计算。通过开展生产现场试验,该系统的测量结果与涡轮流量计相比,平均误差为11.36%,且流量的变化趋势一致,表明本文提出的油井多相流相关流量计量系统能够对油井产出液进行正确、连续、自动测量,从而为油井多相流计量提供一种新的解决方案。

多姿态安装对水表流量性能的影响

流量特性是衡量水表性能的主要指标之一,为探究多流束旋翼式水表在不同安装姿态下产生的流量误差,利用多姿态冷水水表检定装置进行了计量误差试验,得出了水表安装成流动方向为自上而下的垂直方向时,水表流量性能最差,在水表安装成流动轴线处于垂直和水平方向之间的一个中间角度与水表安装成流动方向为自下而上的垂直方向相比,水表流量性能较好,将水表水平安装时,性能最好的结论。在通过Fluent软件的动网格加6DOF方法做了水表的流场仿真,估算出在试验中不同安装姿态在3个流量点情况下的摩擦阻力矩,依据摩擦阻力矩得到仿真误差,与试验误差进行对比分析,证实这些摩擦阻力矩是符合预期且可靠的。

基于组合流量法的城市供水系统小区漏损诊断和预警

近年来,城市供水管网漏损问题频发,小区供水管网作为供水管网的最后一公里,降低小区管网漏损已成为供水企业的重要工作内容。文章针对夜间最小流量移动平均隔差法诊断不及时等问题,提出了一种基于全天流量的判别阈值矩阵分析的漏损诊断预警方法,利用全天流量趋势构建判别阈值矩阵诊断漏损,还将基于全天流量的判别阈值矩阵分析法与夜间最小流量移动平均隔差法结合,提出了一种基于全天流量和夜间最小流量的组合型漏损诊断预警法。将夜间最小流量移动平均隔差法、基于全天流量的判别阈值矩阵分析法和组合流量法分别应用于S市的30个DMA小区,识别准确率分别可以达到73.52%、78.19%和91.28%。结果表明,文章提出的基于全天流量的判别阈值矩阵分析法以及组合型漏损诊断预警法在解决小区供水管网漏损问题方面具有较好的应用前景和实际效果。