电磁流量计使用中常见故障分析

电磁流量计使用中的常见故障,按故障发生时期可分为：安装调试时出现的故障（调试期故障）和正常运行时出现的故障（运行期故障）。按故障外界源头分析来自三方面：包括管道系统和安装方面引起的故障和环境方面引起的故障极其流体方面引起的故障。其中管道系统安装方面所引起的故障主要在调试期表现出来;环境方面和流体方面引起的故障在运行期中表现出来。     

往复压缩机常见故障原因分析及对策

化工企业装置中的往复式压缩机常因某些原因发生故障,造成停机.影响装置安全生产,并给企业带来经济损失.本文在分析了由活塞密封环、气阀及机组管道振动引起压缩机产生故障原因的基础上,提出了相应的解决办法.     

油气管道仪表通信故障智能诊断研究

为保障油气管道生产数据的准确性,降低管道的运行风险,有必要对仪表通信的故障进行实时诊断。针对油气管道自动化生产的特点,对采集的实时运行大数据进行特征分析,获取仪表通信故障特征信号,并且结合专家经验知识、维修人员故障处理实际经验等,建立油气管道仪表通信故障树,基于故障树设计并构建故障诊断专家系统,对仪表通信故障实现智能分析、准确定位,及时提醒相关人员进行仪表通信维检修,从而提高管网的运行安全,为油气管道生产安全的智能化发展提供指导。     

温差载荷与法兰结构故障

1　概述法兰结构在化工生产系统中应用非常广泛。如果法兰结构出现故障,化工生产系统将受到很大影响。因此,我们应该重视对法兰结构的管理,应该对法兰结构的故障机理及故障处理作深入、细致的分析,以提高整个化工生产系统的可靠性。引起法兰结构故障失效的原因很多,在这里我们主要讨论的是温差载荷引起的法兰结构故障失效。温差载荷引起的法兰结构故障失效在换热器、蒸汽管道等温度较高、温差较大的场合可以看到,轻则使密封垫片过量压缩变形,产生泄漏,重则造成法兰变形、断裂或螺栓变形、断裂,而且要对变形的法兰进行检修很不方便。比如:一…     

碳铵取出液分配器

我厂两套碳化系统共配置有稠厚器、离心机各四台。每一套碳化系统的主塔取出液总管,如图(一)各设有四条支管及四个隔膜阀控制,使双系碳铵取出液可同时取向任意一台或二台稠厚器。这样的配管设计看来似无可非义的,但使用中操作繁重,有时因管道堵塞故障而迫使生产减量。在伟大的批林批孔运动中,我们认真学习了毛主席哲学著作,总结经验教训,认识到引起取出操作故障的原因,在于管道配置未能较好地适应     

锅炉高压容器压力管道检验中的裂纹问题与预防办法

锅炉压力容器及压力管道等设备在其运行过程中,会由于不同原因而造成管道产生裂纹,进而影响正常生产,甚至对于锅炉安全造成威胁。本文对于锅炉高压容器压力管道易出现的裂纹问题进行了分析,同时提出预防措施,希望对提高锅炉工作效率、减少故障发生起到一定指导作用。     

熟料烧成控制中菲斯特转子秤常见故障分析

菲斯特转子秤常常发生或设备或工艺或电气控制故障,给生产带来影响。转子秤窜风、煤粉水分大、膜片堵塞都会引起转子秤蓬仓。引起转子秤窜风蓬仓的原因很多,比如送煤风压过高,收尘管道堵塞,转子与模板间隙忽大忽小等等。秤底部测速盘失圆会引起转子秤运行波动。煤粉积存电器元件发热,锁秤螺栓掉落,转子秤会出现"转子故障"信号跳停。     

氯乙烯增压机振动故障分析及对策

简述了 PVC生产中氯乙烯深度脱水工艺增压机的使用现状,重点针对增压机机体及管道异常振动情况,通过制定振动测试方案及现场测试数据分析,找出了引起故障原因,并提出了相应的减振措施,取得了较好的运行效果.     

造气炉故障报警器在生产中的应用

正1存在的问题江苏禾友化工有限公司造气炉在正常运行时,控制吹风的吹风阀和控制煤气输出的下行煤气阀是不能同时开启的,且煤气总阀也必须保持开关自如状态。但是有时因操作不当或设备组件老化、损坏,会出现引起煤气的运行系统吹风阀和下行煤气阀同时开启或关闭不到位,或煤气总阀打不开的故障。出现此类故障会使煤气与空气互窜混合而引起爆炸,轻则炸坏空气管道、管道封头,重则炸坏鼓风机、造气炉,甚至还会造成人身     

化工设备故障分析与检修

分析了几例化工生产过程中因设备选型、管道配置不当造成设备零部件损坏、机械密封泄漏的实例，介绍了相应的处理措施。提出在实际检修过程中，需从工艺角度分析引起设备故障的原因，寻求解决问题的办法。     

液滴撞击微结构疏水表面的动态特性

对去离子水滴撞击不同几何尺寸显微结构方柱和方孔状疏水表面的动态特性进行了研究。结果表明：当液滴以不同速度撞击微方柱疏水表面时,液滴展现铺展和回缩过程,且随着韦伯数（We数）增大,最大铺展直径增大,并伴随卫星液滴出现,但到达最大铺展直径的时间一致;而当液滴以相同的速度（We数相同）撞击间距不同的微方柱疏水表面时,液滴的最大铺展直径随着间距的增大而减小,且铺展过程会液滴浸润状态变得不稳定,发生由Cassie向Wenzel状态的浸润转变。当微方柱间距较小时,液滴受到的黏附功越小,越易发生向Cassie状态的转变;液滴撞击微方孔疏水表面时,液滴以规则的圆环状向外铺展和回缩,最后呈现近似规则的椭球状,不会发生向Wenzel状态的浸润转变,利用建立的物理模型对前述现象进行了分析。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Trapping the western pine beetle at and near a source of synthetic attractive pheromone Effects of trap size and position

Western pine beetles were caught on unbaited sticky traps placed near a source ofexo-brevicomin, frontalin, and myrcene. Size of trap, distance and direction from the source of attractant, and height from the ground were varied. Significant differences in trap catch were observed in relation to each of the variables. Traps close to the source of attractant caught more beetles than traps farther from the source. Traps downwind of the source of attractant caught more beetles than did upwind traps. More males than females were trapped close to the source of attractant.Based in part on a thesis submitted by the senior author to the University of California, Berkeley, California, in partial fulfillment of the requirements for the degree Master of Science in entomology, December 1976. These studies were supported by the U.S. Forest Service and in part by the Rockefeller Foundation and a joint grant (NSF GB-34718/BMS 75-04223) from the U.S. National Science Foundation and the U.S. Environmental Protection Agency to the University of California. The findings, opinions, and recommendations are not necessarily those of the University of California or the funding agencies.Trade names and commercial enterprises or products are mentioned solely for information and do not constitute endorsement by the U.S. Department of Agriculture or University of California.     

一种自适应柱状密封气膜特性分析

提出一种自适应柱状气膜密封,构建气膜-密封环为研究对象,考虑了偏心间隙发散问题,并定义Rayleigh台阶对气膜周期的突变性,建立了气膜雷诺方程和膜厚变化函数关系式的动力润滑数值模型,获得了摩擦副气膜润滑特性,研究结果表明：气膜力随转速和压力升高而增加,泄漏量随压力升高而增加但是随转速增加而下降,说明密封内部压力流占主导地位。随后,利用曲面槽型雕刻技术,结合高速试验台对密封进行测试,结果表明：理论计算模型与试验结果吻合度较高,斜槽区域存在更多擦痕与磨损,说明斜槽浮动性弱于直列槽;但斜槽的切向流动小于直列槽,导致斜槽泄漏量小于直列槽。该研究成果为自适应柱状气膜密封的气体流动规律和应用提供了理论基础。     

Kinetics of organic solvent-soluble and native lipase

Organic solvent-soluble lipase was prepared with a synthetic detergent. The solvent-soluble lipase was presumed to be a complex of the enzyme and the detergent. To investigate the effect of the detergent attachment to the enzyme on the reaction properties, the kinetics of the solvent-soluble lipase and of the native lipase were estimated by using glycerides in a homogeneous solution of buffer and tetrahydrofuran. Analysis of the direct interaction between the enzyme and the substrate could serve to characterize the steric structure around the active site of the lipase. The K_m values also differentiated the solvent-soluble lipase from the native lipase. These findings show for the first time that the detergent surrounding the enzyme molecule may affect not only the solubility of the enzyme, but its kinetics as well.     

Lipid distribution on textiles in relation to washing with lipases

Effectiveness of lipase in detergency was studied using three test soils (lard, artificial sebum, and olive oil) on a woven cotton fabric. Distribution of oily soil on fabrics was determined for three different treatments (unwashed, washed with detergent without lipase, and washed with detergent plus lipase). Osmium tetroxide was used to label lipid soil for analysis in the scanning electron microscope. Both longitudinal and cross-sectional backscattered electron images for unwashed samples showed that soil was present on surfaces of the cotton fibers and in interfiber spaces of the yarn bundle. Lard soiled samples had large deposits on the fabric surfaces, while artificial sebum and olive oil appeared more uniformly distributed throughout the textile. Oil was deposited in the interfiber capillaries of the yarn bundle and in the crenulation, secondary walls, and lumen of the fibers. Energy dispersive X-ray microanalysis was used to determine relative concentrations of oil at selected morphological locations within the fiber structure and at the fiber surface. Soil distributions within the fibrous structures differed with type of soil and laundry treatment. Backscattered electron images dramatically demonstrated the effect of lipase on cleaning. After washing with detergent plus lipase, yarn surfaces had much less residual soil; residual soil that remained was in the irregularities of the cotton fiber surfaces. Concentrations of oil in the secondary walls, crenulations, lumen, and the fiber surfaces were lower after lipase treatment for all three soils. While washing with detergent removed soil from the yarn and fiber surfaces and the crenulation of the cotton fiber, only the samples washed with detergent plus lipase had lower concentrations of soils within the secondary wall and lumen of the cotton fibers. Fabrics soiled with olive oil and washed with detergent plus lipase had the lowest concentrations of residual soil across the textile structure; the residual soil observed was mainly in the irregularities on the fiber surfaces.     

煤油贮箱冷氦鼓泡增压过程数值研究

火箭飞行过程中,约90 K的低温氦气用以加压室温下的煤油贮箱使煤油流出,保障发动机燃料供应。为尽可能减少氦气用量,设计低温氦气从液相中喷入,使得氦气在贮箱内上升过程先和液态煤油充分换热升温,再进入气相空间增压。但该过程可能引起两个不利的结果,首先浸没在煤油中的低温氦气管路表面可能结冰,结冰沉底或可能堵塞发动机滤网;其次氦气可能被煤油携带,从而排出口位置可能出现气液两相流。这两种情况都对火箭发动机稳定运行造成负面影响,因此是不允许的。对低温氦气在贮箱中心喷入和环向多孔喷入两种结构的气液两相流过程进行了数值研究,构建了基于Euler-Euler模型的两相传热非稳态模型,数值结果与地面实验观察到的现象进行了定性对比,定性验证了模型的准确性。重点考察了煤油排出过程两种喷入结构的气液两相流分布以及煤油结冰可能性。研究结果从机理上解释了实验现象,并为煤油贮箱增压排出方案设计提供了参考。     

Modified dynamic matrix control

DMC (Dynamic Matrix Control) has been used successfully in industry for the last decade. It can deal with constraints and unusual dynamic behavior directly. It also shows a good control performance for the servo problem. Relatively, it can’t reject disturbances systematically. We propose a modified DMC method to control the regulatory process more efficiently. The proposed DMC method makes the control output by subtracting the estimated disturbance from the control output of the original DMC. Here, the disturbance is estimated by a new disturbance estimator. It shows better control performances than the original DMC.     

Analyse Expérimentale et Numérique du Comportement de Membranes Thermoplastiques en ABS et en HIPS dans le Procédé de Thermoformage

In this work, we are interested, on the one hand in the characterization of circular polymeric ABS and HIPS membrane under biaxial deformation using the bubble inflation technique, on the other hand in modelling and numerical simulation of the thermoforming of ABS and HIPS materials using the dynamic finite element method. Hyperelastic models (Mooney‐Rivlin, Ogden) are considered. First, the governing equations for the inflation of a flat circular membrane are solved using a variable‐step‐size‐finite difference method and a modified Levenberg‐Marquardt algorithm to minimize the difference between the calculated and measured inflation pressure. This will determine the material constants embedded within the models used. For numerical simulation, the lagrangian formulation together with the assumption of the membrane theory is used. Moreover, the influence of the hyperalastic model on the thickness and on the stress distribution in the thermoforming sheet are analysed for ABS and HIPS materials.     

回灌过程中离子强度和水流流速对胶体粒子在多孔介质中堵塞的影响

人工回灌过程中的堵塞问题一直是影响其推广的瓶颈,目前回灌过程中大颗粒悬浮物导致的堵塞机理研究较多,对胶体类颗粒物的堵塞机理研究相对少。采用室内砂柱实验,研究不同离子强度和不同水流流速条件下胶体在饱和多孔介质中的迁移-滞留特征。选择大肠杆菌为实验胶体,设计在不同离子强度、不同水流条件下的砂柱回灌实验;运用Hydrus-1D软件模拟,拟合穿透曲线后得到表征胶体沉积的相关参数。实验结果表明,在相同的离子强度下,流速增大会促进胶体的迁移,穿透曲线峰值增高,胶体的吸附率减小。在中等离子强度条件下（IS=30、50 mmol·L^-1）流速对胶体的这种影响比在更低的离子强度（≤10 mmol·L^-1）或更高的离子强度（≥300 mmol·L^-1）条件下更为显著;相反地,同一流速条件下,离子强度从10 mmol·L^-1升高到300 mmol·L^-1时,胶体的吸附随着离子强度的增加而迅速增加。从胶体和介质相互作用势能来看,随着离子强度的增加,胶体和砂表面的相互作用增强,有利于胶体吸附在介质表面,增加介质堵塞的概率。但是,在一定的离子强度下,流速的增加产生的水动力剪切力有利于促进胶体的迁移,不利于胶体的吸附或阻塞,减少了微小颗粒堵塞的概率。模拟结果显示吸附速率系数k、最大固相沉积量S_max随着离子强度的增大而增大,随着流速的增大而减小。从整体上来看,回灌过程中胶体微粒的迁移滞留行为主要受控于离子强度,但水流因素会干扰离子强度的控制作用。在实际的人工回灌过程中,有效的预防堵塞需要将化学（降低离子强度）和水动力（增加回灌水流速）手段有效地结合起来。