熔融尿素泵机械密封的改进

在尿素生产中,熔融尿素由离心式的熔融尿素泵(简称熔融泵)送至尿素造粒塔顶进入旋转造粒喷头进行造粒。熔融泵工作情况的好坏,直接关系到尿素的造粒能否正常进行,而熔融泵机械密封的可靠性,泄漏量和使用寿命又决定着熔融泵能否长周期稳定运行。     

滚筒造粒过程先进控制系统设计

为解决小规模连续造粒生产的自动化控制问题,设计一种基于WinCC Flexible和S7-300PLC的低成本集散控制系统,说明了系统的软硬件构成情况。在系统平台基础上,研究了滚筒造粒工段各子系统的控制方法。最后针对造粒过程大滞后、多变量特点,提出先进控制算法在滚筒造粒机上的实验方案。     

压力式喷雾干燥机设备改造与出料效率的提升

随着科技的发展,我国工业陶瓷生产的制作工艺也有了很大的进步,其中设备的不断更新完善以及喷雾造粒工艺的提升占据了重要地位。本文分析了当前喷雾造粒设备的构成、喷雾造粒设备及其工艺,分析了影响造粒粉料工艺性能的因素,并对干燥塔的效率影响因素进行了分析和研究。     

振动流化床喷雾造粒的研究

振动流化床喷雾造粒的研究东北大学单宝峰，张继宇辽宁省机械研究院丁颖一、引言用振动流化床喷雾造粒，是振动技术、流态化、喷雾技术的综合应用，集混合、造粒、干燥于一体，在同一封闭容器内实现一步造粒，与传统的造粒法相比具有许多优点：工艺流程简单、设备紧凑、能...     

挤压造粒机组常见故障和解决措施

挤压造粒机组是工业生产的一个重要组成部分。本文研究挤压造粒机组常见故障,分析液压缸漏油、油路带气、进刀不及时、异常颗粒、颗粒的水流量少以及切刀的磨损程度较大产生的故障原因,给出挤压造粒机组常见故障的解决措施,从而能够有效处理挤压造粒机组常见故障。     

浅谈延期药圆盘造粒机的设计思路及造粒实验

圆盘造粒是工业化大吨位造粒技术,制备颗粒具有粒度均匀和流散性好等特点。本文以常见延期药粉体为依据设计出适合延期药造粒的圆盘造粒机,并以氧化剂为粉体原料,以喷雾方式加入黏结剂,在圆盘倾角50°和转速为35r/min条件下进行造粒,得到产品经过显微镜分析和粒度分析发现,颗粒球形度高、流散性优良和表面光滑,81%的颗粒粒度分布在30～80目,生产能力达到12kg/h。     

造粒系统仪表常见故障及处理

某厂生产的液硫输送至造粒系统,经过造粒系统处理后包装出产品。若造粒系统因仪表出现故障而不能正常运行,将导致液硫无法及时处理,液硫池装满以后会导致装置停车。该文介绍了造粒系统结构及仪表常见故障,重点讨论了仪表常见故障的处理过程。     

一种聚丙烯酰胺造粒机的设计

设计了一种专门用于生产聚丙烯酰胺颗粒的胶体造粒机,改变了传统的挤出造粒方式,利用多级切割造粒,减弱了挤出造粒对胶体的挤压破坏作用。设备采用变频控制,实现无级调速,造粒粒度范围宽。     

大连橡塑成功改造大型进亡挤出造粒机核心装置

日前,大连橡胶塑料机械公司通过改造,使进口30万万t／年大型挤压造粒机组减速箱实现平稳运行。这是国内企业首次承担进口大型挤压造粒机组老设备核心装置改造工作,标志着中国在大型挤压造粒机组生产及改造上全面实现国产化。     

基于PLC的混合造粒控制系统设计

混合造粒设备是一种将几种不同粉料组分混合加工成颗粒状混合爆炸物的设备。根据混合造粒设备实际生产控制要求,设计了基于上位机和可编程控制器的混合造粒自动控制系统,实现了整套工艺设备的现场控制、参数设定及过程监控等功能。论述了控制系统的整体架构、硬件软件的设计以及系统的通信实现。     

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...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

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。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.