闸板式混凝土泵左主油缸为什么停顿?

我单位生产的一台ＨＢＴ６０型闸板式混凝土泵在使用５个月后突然出现左主油缸在每次推进过程中停顿一下的故障现象。停顿时间不到１ｓ,此时,泵送混凝土的工作尚能继续进行,主油泵出口压力正常,液压系统也没有出现外泄漏现象,并且右主油缸及两个滑阀缸的动作也未见异常。该机的主油路液压系统原理见附图。根据上述故障现象及液压系统原理可以确认,该混凝土泵液压系统中的压力保证元件和左、右主油缸的换向间均无故障。因此,引起左主油缸在推进过程中停顿是因左主油缸在推进过程中出现瞬间供油中断造成的。从原理图可知,左主油缸４推…     

基于DSP的混凝土泵排量测量装置设计

混凝土泵排量测量装置已被视为新一代混凝土泵的标志性功能.介绍了混凝土泵排量测量的工作原理,通过将压力传感器安装在主油缸进油油路上,测量主油缸压力,对主油缸压力进行分析,计算实时泵送效率系数,实现对混凝土泵排量的测量.阐述了混凝土泵排量测量装置的硬件设计和软件设计.排量测量装置的软件设计采用模块化结构设计方法,将排量测量装置按照功能模块划分为子程序,子程序之间相对独立也可以相互调用.对混凝土泵排量测量装置的抗干扰措施进行讨论.     

液压支架油缸泄漏的主要原因与解决方案研究

为有效解决煤矿液压支架油缸在工作过程中经常产生的各种故障问题,减小对整个煤矿开采工作造成的不同程度的影响,首先针对煤矿液压支架油缸特点进行分析,有效找出液压支架油缸产生泄漏问题的主要原因,并提出针对性的解决方案加以处理,使得液压支架油缸故障问题得以顺利排除,有效保证了煤矿开采工作的安全性和稳定性.     

重型汽车驾驶台举升油缸缸底结构改进设计

为了解决重型汽车驾驶台举升油缸举升缓慢和自锁失灵问题,在分别分析造成举升油缸自锁失灵和不举升原因的基础上,利用在工程应用中边实践,边研究的方法,给出了问题的解决方法.结合给出的解决方法对举升油缸缸底进行了结构改进,对改进前后油缸启动时间进行了对比计算,结果表明改进后结构可以有效提高举升油缸的启动速度,降低故障发生可能性;另外,通过对油缸缸底盲孔段污染物堆积和外泄问题分析,提出了油缸缸底结构设计中的合理建议.     

铸机结晶器调宽液压缸在线检测内泄方法的实现

该文对某炼钢厂铸机结晶器调宽伺服油缸的控制原理进行了分析,并针对无法进行在线检测油缸内泄的问题采取了便捷有效的处理方法.该方法的实施在减少结晶器调宽故障方面起到了重要的作用.     

回转轴缸中密封结构的改进

受郑州第二钢厂的委托,我们对该厂原有进口油缸进行了改造设计,改进后的结构如图1。 图1 1.缸体 2.活塞杆 3.进回油装置 4.活塞 该油缸为回转油缸,在进回油的同时,缸体要做回转运动。根据油缸的损坏特点及故障原因分析,我们除了对缸体的结构及加工工艺性的改进     

卷取机上压辊油缸端盖螺丝断裂故障分析

根据卷取机液压系统的工作原理,对卷取机上压辊油缸端盖螺丝断裂故障进行了分析,并对液压系统进行了优化.     

连铸机脱引锭液压系统故障分析及优化设计

根据连铸机脱引锭液压系统的工作原理,对脱锭油缸无动作的故障进行了分析,并对液压系统进行了优化设计.     

轧钢步进梁油缸爬行故障分析与诊断

根据轧钢步进梁液压系统的工作原理,对步进梁油缸出现的一例爬行故障进行了分析与诊断.     

基于泵送压力的混凝土泵排量计量方法

分析现有混凝土泵排量计量方法的特点,指出现有计量方法在计量精度方面的不足.根据混凝土泵工作原理建立混凝土泵排量数学模型,指出计量混凝土泵排量的关键是实时泵送效率系数.分析影响实时泵送效率系数的因素以及混凝土缸压力与主液压缸压力之间的关系,提出基于泵送压力的计量方法.通过直接测量混凝土泵主油缸压力,分析主油缸压力变化趋势,计算实时泵送效率系数,对混凝土泵实际排量进行计量.试验表明,所提方法具有较高计量精度.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.