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排气阀是柴油机的重要运动件之一,排气阀密封面合金层的质量决定了排气阀使用寿命。自行研发的排气阀制造新工艺——真空熔焊与硬化处理,实际效果明显,在不改变任何材料的前提下,排气阀阀面合金层的硬度达到60.6HRC,金相组织达12级以上。 相似文献
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排气阀的工作环境是极其严酷的,因此,排气阀的损坏是许多船舶经常遇到的问题。本文介绍了柴油机排气阀的一些常见损坏形成,并对某轮主机排气阀烧损事故进行了较为透彻的分析。指出冷却水中断是导致排气阀烧损的原因之一。 相似文献
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1980年代中期,MAN B&W研制了著名的排气阀腔室阀座,让一小部分扫气空气存储在与阀座连成一体的腔室内,降低与废气通道毗邻区域的阀座的温度,降低阀座材料的热应力,有效地增加了排气阀检修间隔时间,延长其工作寿命。 相似文献
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6L48/60型主机排气阀破断故障分析 总被引:1,自引:0,他引:1
6L48/60型船用柴油机主排气阀运行中在距阀盘100 mm的阀杆处发生完全破断.排气阀的材料为4Cr9Si2,用锻造工艺加工制造.对破断的排气阀进行了金相、断口及能谱(EDS)分析,结果表明,排气阀在运行过程中发生了热腐蚀,断裂方式为高温腐蚀疲劳破坏.断裂原因为阀体材料4Cr9Si2的抗热腐蚀能力较差,加速了疲劳裂纹的萌生与扩展. 相似文献
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三菱6UEC 60LA船用柴油机排气阀的测量研磨技术 总被引:1,自引:0,他引:1
排气阀是柴油机的重要的组成部分,它的工作性能的好坏直接影响到主机的运行。结合目前常用的液压驱动排气阀的工作原理,重点介绍了三菱6UEC60LA型船用柴油机排气阀的测量与研磨技术所需注意的事项,并进行较深入的分析。 相似文献
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通过考察、研究,并经试验室试验,提出了大功率低速柴油机排气阀结构改进和国产材料代用的设想;同时对研制工艺也进行了深入的试验和研究。 相似文献
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针对MANB&W柴油机排气阀材料为镍钛硬质合金的特点,结合使用和维护保养的要求,对其检修工艺作了全面的介绍。 相似文献
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MAN—B&WMC/MCE主机排气阀传动机构为液压式,开阀靠液压驱动装置(由凸轮轴滑油泵供油)产生的油压,关阀靠“空气弹簧”的气体压力。 相似文献
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此文从主机排气阀常见的烧损故障入手,在分析了MAN B&w MC型船舶主机排气阀结构特点的基础上,结合实船工作经验,总结了主机排气阀在拆检、研磨、组装及日常管理中的注意事项。 相似文献
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介绍了我国港口资源的整合现状,指出港口整合可以提升港口的形象和地位,也为区域经济和城市的发展注入强大的动力。最后指出在港口资源整合中要避免的几个问题。 相似文献
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广州集装箱码头的轮胎式场桥小车制动器使用10多年后,出现了许多问题,故进行了改造.分析了轮胎式集装箱龙门起重机小车制动器的主要故障现象,提出了改造方案,并加以实施. 相似文献
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本文对现有的选定球面轴承的三种工程方法进行了分析比较.引入了“合力系数”,并给出了合力方向上投影面积的精确解. 相似文献
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分析柴油机故障中常见的机体裂纹故障原因,认为由于设计缺陷和管理及操作不当,易造成船舶柴油机缸体上的裂纹多发生在气缸套凸肩处。如不及时处理这些裂纹和故障,就会造成缸套的裂纹直至出现缸套漏水等严重后果,针对NANTAIQUEEN轮柴油机对该类型故障的检修提出具体措施。 相似文献
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The hydrophysical and hydrochemical structure of the Sea of Azov, with developed bottom anoxia, was studied during the RV “Akvanavt” cruise from July 31 to August 03, 2001. The anoxic zone with a thickness from 0.5 to 4 m above the bottom was found in all deep regions of the Sea. Concentrations of hydrochemical parameters were similar to the pronounced anoxic conditions (about 90 mmol m− 3 of hydrogen sulfide, 17 mmol m− 3 of ammonia, 6 mmol m− 3 of phosphate, 7 mmol m− 3 of total manganese). The hydrophysical structure was characterized by the uniform distribution of temperature in the upper 6–7 m mixed layer (UML). Below this a thin (0.4–0.8 m) thermocline layer was observed, just above the anoxic waters. Formation of this phenomenon was connected with that summer weather conditions. Intensive rains led to increased influx of river waters in June. That resulted in large input of allochtonous organic matter (OM) and inorganic nutrients; the latter were consumed on the additional autochthonous organic matter production. In July the weather was characterized by a significant rise in the daily averaged air temperature and large oscillations of temperature during the day. In this period a wind of constant direction was absent, but wind bursts were observed. The completed analyses showed that the formation of such a structure could be connected with the following factors: (i) positive growth trends of the daily averaged temperature and the daily oscillations of temperature, (ii) presence of wind bursts. The joint action of these factors resulted in the formation of the UML. The amplitude of wind bursts determined the depth of UML, and the value of trend determined the value of the temperature change in the thermocline. An initial presence of bottom halocline (caused by the Black Sea water influx to the bottom of the Sea of Azov) prevented the heating of the bottom layer and therefore led to an increase of vertical gradient of temperature in the thermocline. The spatial distribution of the turbulent exchange coefficient confirmed the existence of a “stagnation” area located above the anoxia zone, which is also, apparently, the reason for its occurrence. 相似文献