普通速度式机械水表计量精度影响因素的探讨

水表的计量精度直接影响到供水企业的经济效益和服务质量。通过对影响普通速度式机械水表计量精度的各种因素的分析探讨,提出了水表日常管理中应注意的一些问题,认为加强水表选择、安装和服务等环节的管理,才能保证水表计量的科学性、准确性。     

数据采集设置对DMA流量模式的影响

智能水表监测的水量数据为用水模式确定及供水管网漏损分析提供了重要的基础。然而，数据精度与频度会对分析结果产生重要影响。以10个独立计量区（DMA）入口流量计数据作为基础样本，分析了数据采集周期与精度对最小夜间流量计算以及DMA流量模式分析的影响。结果表明，水表数据采集周期增加会导致最小夜间流量计算结果增大，同时降低流量模式的精细度；数据精度降低会导致流量模式呈阶梯状甚至双线式，无法反映真实的用水模式。水表数据采集周期与精度存在对应关系，在设定时需要相互匹配。     

住宅水表的精度等级及应用

住宅水表是指安装在用户家中或户外,针对家庭用水进行计量的水表,其口径为DN15～DN25,也称小口径水表。 过去,由于供水部门只抄表收费到单元楼或小区前,因此对住宅水表的质量和精度等级并不关心。而现在,随着一户一表计量收费工作的开展,供水部门为了降低自来水的产销差,杜绝不良用户用滴水使水表在小流量下计量不准等现象,正在逐步采用精度等级更高的水表。     

浅谈对C级水表的应用研究

国家标准GB778-1996把水表划分为A级、B级、C级和D级四个等级，不同等级的水表有不同的计量范围和计量精度。目前，我公司使用的水表绝大部分是北京京兆水表公司生产的B级表，也有少量A级水表。为了提高水表的计量精度，减少水量计量损失，宽量程、高精度的C级水表将逐步替代A级和B级水表，这是水表技术发展应用的必然趋势。     

关于容积水表误差变化的探讨

水表是供水调度生产、抄表收费、检漏降耗、节约能源的必要技术手段,水表计量准确性直接影响供水企业的经济、社会效益,与千家万户的切身利益密切相关。通过对我公司在用DN15容积水表进行抽样检测和分析,以探求容积水表计量精度随使用年限的增加而产生变化的规律,进而探索科学的使用周期,指导我公司的周期换表。     

浅谈如何确保水表计量准确

水表是计量用户使用水量的仪器,是用户交纳水费的依据。城市供水需要使用大量水表,故水表计量准确与否直接关系到供水公司的营业利润,也是我们进行降低管网水量漏失率工作的重要环节。如何把好水表计量精度这一关,首先必须清楚保证水表准确计量的一些条件和因素：     

高灵敏度水表实用化研究及经济效益分析

以佛山水业公司为例,通过开展水表串联试验及实用化试验,对比了高灵敏度水表与普通机械水表的实际性能,评估了新型高灵敏度水表的经济效益,试验表明,高灵敏度大口径水表与普通大口径水表相比,在常用流量段计量效率一致,但在低流量段,高灵敏度大口径水表计量效率远高于相同口径普通机械水表。     

基于GIS的城镇需水量空间分析研究

本文提出应用 GIS 空间叠置分析、空间统计分析等 GIS 空间分析方法揭示供水区需水量空间分布规律及特征。以广东省 NZ 镇供水区为例,以其大用户水表地理位置探测数据及供水营业收费数据等为主要信息源,采用 Maplnfo 软件分析得出了 NZ 镇需水量的空间分布规律与区位特征;并提出在正常供水中断情况下,利用大用户水表地理信息采用聚类方法确定最优应急供水点位置的方法。     

水表性能参数的分析及规范性表述

针对各种版本教材和设计手册中对水表技术参数表述不规范、叙述不统一的情况,结合水表生产和使用中所遵循的相关规范和技术标准进行综合分析,归纳和理清水表技术参数的实际含义。并在此基础上,以最新国家标准为依据,结合水表产品样本分析和实际选用过程的需要,提出了关于水表性能参数统一规范化表述的建议,对实践教学和工程设计具有一定的参考价值和指导意义。     

柳州维义大桥桥墩沉降监测运用中点三角高程测量方法的精度分析

随着测距技术的发展、测距精度的提高,三角高程测量方法正逐步受到广大测绘工作者的青睐,本文通过工程实例,介绍了运用中点三角高程测量对离岸桥墩进行沉降监测的方法,并对这种测量方法的误差来源及精度进行了分析。阐述了这种测量方法在工程测量运用中的高效性、灵活性和实用性。     

Performance analysis of the domestic water meter park in water supply network of Ibarra,Ecuador

Apparent losses are one of the most important components of non-revenue water and mainly caused by water meter under-registration. This paper studies the performance of a water meter park from a developing country water utility in Ibarra city, Ecuador. The study includes three major aspects: water meter error curve reconstruction with seven different flow rates; water meter evaluation as a function of class, manufacturer and totalized registered volume, use of two water consumption patterns for weighted error determination and their influence on water balance and performance indicators analysis. Results indicate that 44% of analyzed meters works at optimal conditions. Weighted error obtained by using two different consumption patterns indicates a 0.95% difference, which has an important impact on water balance and performance indicator results. This detailed analysis of water meters can help to develop a more efficient water meter replacement strategy and to estimate apparent water loss volume more accurately.     

Quantifying measuring errors of new residential water meters considering different customer consumption patterns

Water meter measuring errors vary depending on the water flow rate. The difference between water actually consumed and registered by a meter will differ depending on how water consumption is distributed by flow rates. Published studies assessing the performance of new residential meters have only analysed the error curves of the meters – without calculating the influence that consumption patterns have on their field performance. In most cases, research has been limited to analysing compliance with published standards. This work presents an evaluation of the actual commercial losses to be expected considering the consumption characteristic of domestic users. Several types of residential meters have been tested and the error curves obtained have been combined with measured consumption patterns of domestic users. As a result, this paper provides information about the order of magnitude of the initial measuring error as a function of the residential meter model and user characteristics.     

Accuracy of single-jet water meters during filling of the pipe network in intermittent water supply

In intermittently operated water distribution systems the air intruded into the pipe network through the filling and emptying process must inevitably exit the system at some point. Part of this air is discharged through service connections and thus through water meters. Due to this air flow, water meters are being used contrary to their actual conception. This article presents a study in which the measurement error of single-jet water meters due to the filling process of an empty service connection is experimentally examined. It shows that this error is caused mainly by the air flow before the water front reaches the water meter. The correlation between the measurement error and the air volume in front of the water meter is almost linear. The impact of the water front, the presence of water-air mixtures or unsteady flow processes however, is shown to have very little influence on the results.     

餐饮用户燃气表的管理

分析了餐饮用户燃气表存在的问题，比较了皮膜表与智能表的准确性、皮膜表与罗茨表的相对误差与性能，提出了解决办法。     

A composite indicator for water meter replacement in an urban distribution network

In water supply management, volumetric water meter are typically used to measure users' consumption. With water meters, utilities can collect useful data for billing, assess the water balance of the system, and identify failures in the network, water theft and anomalous user behaviour. Despite their importance, these instruments are characterised by intrinsic errors that cause so-called apparent losses. The complexity of the physical phenomena associated with metering errors in aging water meters does not allow meter replacement to be guided by single parameters, such as the meter age or the total volume passed through the meter. This paper presents a meter replacement strategy based on a composite ‘Replacement Indicator’ (RI) that aims to reduce apparent losses. The performance of a meter during its operating life was analysed by means of this indicator, which signals when the meter needs to be replaced. To test the reliability and robustness of the proposed indicator, a Monte Carlo uncertainty analysis was performed. The methodology was applied to a real case study: a district metered area (DMA) in the Palermo city water distribution network (Italy). The analysis showed that ranking based on the composite indicator is better than common ranking procedures based on typical variables (e.g., the meter error curve or the meter age): the proposed indicator can better select the meters to be replaced and favourably affect the associated costs.     

GPS RTK技术在榆林市加密控制测量中的应用

分析了RTK技术及其定位原理，详细地介绍了RTK技术在榆林城市加密控制网测量中的应用，对RTK的精度进行了分析研究，得出了RTK完全可满足在四等网下加密城市控制网的精度要求，且各点间不存在误差的结论。     

户表改造中水表保温措施研究

针对户表改造中水表的防冻保温措施进行了研究,为了解决北方城市冬季水表的冰冻问题,通过试验,研究了不同湿式水表的防冻性能,水表外套保温材料延长对水表冻结时间的影响,并验证了现阶段使用的单只水表表箱的防冻性能。     

桥梁施工控制网的精度分析探讨

介绍了施工控制网精度的确定方法,通过对桥梁误差的来源以及误差分配原则进行分析,进而根据桥梁施工的方式提出了两种控制网精度的确定方法,以保证工程质量,更有效地提高施工效率。     

Groundwater seepage nutrient loading in a Florida Lake

Twenty-five seepage meters were positioned in East Lake Tohopekaliga, Florida, to determine groundwater seepage contributions of water and nutrients to the lake in 1983. Seepage was found to be an important source of water to the lake, contributing 14.3% of the water sources, and rates decreased significantly (P < 0.01) with distance from shore. A comparison of the piezometer and seepage meter techniques for measuring nutrient loading to the lake indicates the direct seepage meter technique overestimated nutrient inputs due to the enclosure to the sediments, possibly resulting in anaerobic conditions and increased release rates of ammonium nitrogen and phosphate. These results suggest that past studies employing this technique may be in error. Nutrient loading, calculated from piezometer nutrient data and seepage meter flow data, show that the groundwater nutrient loading in the lake was significant, contributing 8.7 and 17.6% of the total phosphorus and total nitrogen inputs to the lake, respectively.     

灰色关联度分析在观测评定精度中的应用

介绍了灰色关联度分析的一般步骤，分析了其应用方法，比较了应用关联度和中误差对精度的衡量结果，表明了运用灰色理论中的关联度分析评定观测精度，所需观测数据少，且评定的精度满足工程需要。