广蓄A厂与惠蓄电厂主轴密封对比分析

详细分析了广蓄和惠蓄电厂法国机组主轴密封的特点,通过对比两厂密封结构上和安装上的差异,阐述了碳密封环和高分子密封环对冷却水不同的敏感性。     

滚齿机滚刀主轴水冷保护焊接修复

Y31125滚齿机滚刀主轴材料09Mo2VA,高频淬火后HRC58。由于硬度较高且承受较大切削力,常因操作不当而断裂。由于订货周期较长,为保证机床的正常运转,我们对断裂后主轴采用了水冷保护焊接修复。     

CCS水电站主轴密封及导轴承安装

厄瓜多尔科卡科多辛克雷水电站(简称CCS水电站)安装8台套单机容量为205 MVA的立轴水斗式水轮发电机组,依据设计要求主轴密封装置在水轮机压气工况下运行时主轴密封才投入,防止压缩空气从主轴密封溢出;在正常运行(无压运行)时主轴密封切除。该电站水轮机主轴密封结构特点与其他机组结构形式不同,本文针对该电站主轴密封的结构特点和安装施工工艺进行详细阐述,供其他同类电站借鉴。     

思林电厂工作密封条更换工艺的改进

为了提高思林电厂HWG2082Mo密封条更换的效率、避免影响检修工期,笔者对思林电厂工作密封的机构及传统更换工艺的不足进行分析,提出了通过拆卸工作密封环、反置安装好密封条后再组拼密封环、在滑环上涂抹黑墨水使高点凸显等改进措施。通过实际运用表明,改进措施实用可行,大大提高了工作效率,将检修时间由原来的7 d缩短到2 d。该方法对同类型、同材质工作密封条的更换有一定的借鉴作用。     

成都赛思德工业设备有限公司

<正>赛思德尔(CESTIDUR~)高分子材料由法国CESTIDUR INDUSTRIES公司开发生产。CESTIDUR INDUSTRIES是专门生产高分子材料半制成品的公司,从事高分子材料的研究开发已经超过40年。长期的技术研究和先进的设备支持保证了赛思德尔材料的高标准和高性能。CESTIDUR INDUSTRIES公司作为高分子材料的全球领先者,拥有其他家材料供应商所不具备的众多优势:更强大的资金后盾;更专业的技术支持;全球化的先进应用经验;全面的材料供应系统。赛思德尔材料的综合性能优秀,在水轮机中可用于主轴密封块、抗磨板、轴套和垫片,承担更韧性负载和耐磨的工作。国际水电行业巨头阿尔斯通长期以来都是我们的良好合作伙伴,赛思德尔在国内水电行业的使用也是由该公司引进     

浅谈现浇混凝土水池施工技术及防水措施

文中就现浇钢筋混凝土水池施工特点及分区施工的方法进行了介绍,对水池安装钢板止水带分部施工及设置橡胶止水带分区施工工艺进行了对比分析,新型高分子材料取代钢板止水带、橡胶止水带工艺具有无可比拟的优势。     

叶片式主轴密封及其应用

中小型水电站采用接触式主轴密封结构,磨损后漏水问题较为突出。为解决该问题,设计了一种新式主轴密封——叶片式主轴密封,其主要特点是采用间隙式结构,在恰当选取结构参数后便可达到在机组运行中不漏水。该主轴密封制造、安装简单,使用寿命长,克服了以往主轴密封接触磨损的缺陷。     

多布水电站主轴密封的结构特点和安装工艺

水轮机主轴密封是水轮发电机组的关键部件之一,直接关系到机组的安全运行、检修周期以及电站的经济效益。本文主要介绍多布水电站主轴密封的结构特点和安装工艺,可为其他灯泡贯流式水轮机主轴密封的设计和安装提供参考。     

聚氨酯弹性嵌补材料的研制与应用

聚氨酯是一种性能优越的高分子合成材料,根据所采用的原材料及其配方不同可以制成多种产品。诸如塑料、橡胶、粘结剂和涂料等。聚氨酯作为嵌缝材料是另一种新的应用领域。国外已较多的用作建筑工程的高弹性密封材料,国内于七十年代初开始将聚氨酯用于地下工程和水库大坝的化灌堵水,效果较佳。我们根据水电工程的特点与要求,研制了低弹模聚氨酯弹性嵌补材料。该种材料外观为黑色胶泥状物质,硫化后具有一定的力学强度和弹塑性,且与水泥砂浆或混凝土有较高的粘结力,抗渗性能、低温柔性好,可冷嵌施工,工艺简单,适用于水电工程中混凝土变形缝的     

富金坝水电站机组主轴轴线定位及调整方法

文章介绍了富金坝水电站灯泡贯流式机组主轴轴线定位及调整方法,重点分析了管形座、尾水管安装偏差和主轴倾斜角等因素对机组主轴轴线定位及调整的影响,为该类型机组主轴的安装及检修提供借鉴.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。