利用系统分析方法判断处理电气异常故障

电气故障中，有些并非属于电气设备本体故障，而是因为生产系统中其它原因造成的电气保护，这样有时很难快速判断出故障部位，应通过系统分析的方法进行判断处理，有些故障还需有一个技术分析认识的过程，在排除电气自动化设备问题后，再逐步分析系统中其它引起故障的原因，因此要求电气技术人     

几例电气异常故障的判断和处理

<正>电气故障中,有些是属于电气本身的故障,而有些则属于生产系统中其他原因造成的。因此当遇到电气故障时应进行认真仔细的观测和分析,以确定     

电气控制回路中的隐性故障及其处理办法

电气自动控制系统中，由于控制回路薄弱环节(如触点)或设计时考虑不周所带来的电气故障或电气安全隐患，都可以称之为隐性故障。此类故障不常见，且具有一定的潜伏性和隐蔽性，因而易被忽视，从而引发设备安全事故。笔者现以我公司水泥磨控制回路中存在的两例隐性故障及处理措施，来谈谈这方面     

分析电气原理图诊断数控机床常见故障

电气原理图主要用来描述电气线路的构成及其工作原理,表明电气控制系统中各电气元件的作用及相互关系,对电气控制系统的安装接线、运行维护、故障分析、维修管理等有重要的作用。利用电气原理图可弄清各元器件之间的相互关系及控制信号的走向,这样才能在数控机床发生故障时,快速、准确判断故障原因,排除故障,及时恢复生产。     

使用第一故障鉴别器快速判断联锁回路开路故障

针对ＰＴＡ输送系统鼓风机原电气联锁控制回路存在的缺陷，设计并采用了第一故障鉴别器，有效的解决了故障及时准确定位的难题。     

机床电气设备维修要点分析

首先分析了机床常见的电气故障,并对机床电气故障的维修和故障排查要点展开详细论述,为机床电气设备故障维修提供资料参考。     

用欧姆龙PC机改造打包机电气控制系统

采用PC机改造打包机电气控制系统，打包机故障率比改造前大大降低，且故障的检查，排除方便易行，缩短了故障处理时间，保证了机体运行的连续性，介绍了改造设计和硬件系统组成，软件编程。     

氯气压缩机油泵电控系统改造

阐述了氯气透平压缩机油压低报连锁停车的原因,提出了雷击、系统瞬间短路等自然灾害及电气故障引起的电网低、电压晃动的改进措施。     

台泥英德项目的电气自动化设计

详细介绍台泥(英德)水泥有限公司2×5000t/d熟料生产线工程的电气自动化设计,其中包括供配电系统,电气拖动控制,自动化仪表配置,车间控制及防雷接地和计算机控制系统等.该工程已投运进入稳定的商业生产期,运行至今未发生因电气自动化设备故障而引起的停窑停产现象.     

球磨机联锁保护系统改造

两台球磨机联锁保护系统采用电气联锁方式,联锁繁琐,故障频发,严重影响设备的正常运行。根据这一状况对设备联锁保护系统进行了改造,改造后效果显著,保证了设备正常运行。     

Füllstand- und Durchflußmessung in verfahrenstechnischen Anlagen

Measurement of Level and Flow in Processing Plants The author reviews the processes and systems for the measurement of level. The devices are described for indicating the states ?Full”? and ?Empty”? in the automatic charging and discharging, for continuous measurement in the monitoring of the stores and processes, for measuring systems based on specific properties, such as conductivity and capacity, for electromechanical systems, for non-contact measuring procedures based on sonic and ultrasonic echometry as well as radioactivity, for microwave systems, and for the measurement of aggressive products and substances under high pressures and temperatures, and, in explosion-proof plants. In the measurement of flow, inductive flowmeters of high precision and reliability are used for conducting liquids; corrosion-resistant turbines are used for all products with low viscosity; tooth wheel flowmeter are used for highly viscous materials. The processes for the measurement of level and flow are described in an example for the treatment of waste water.     

少烟三元乙丙橡胶材料研制

以三元乙丙橡胶(EPDM)为基体材料，三氧化二锑、十溴苯醚为阻燃剂制备了材料配方，试验了三氧化二锑(Sb22O3)、十溴苯醚(DBDPO))配比对材料烟雾和力学性能的影响，测试了材料的氧指数，可见光的透过率，自熄性等。结果表明，DBDPO与EPDM的相容性比较好，Sb2O3的相容性则相对比较差，两者都可以提高材料的阻燃性能。以4045EPDM橡胶为基体材料，当EPDM100g，白炭黑10g，二硫化四甲基秋兰姆(TMTD)2g，ZnO5g，促进剂M1g，硬脂酸2g，硫磺3g，Sb2O3和DBDPO质量比为20．0／40．0，可以获得具有较好力学性能的少烟EPDM橡胶材料。     

Determination of Several Valences of Iron, Arsenic and Antimony, and Selenium in Glass

Methods for the analysis of silicate glasses are described for ferrous iron, for tri- and pentavalent arsenic and antimony when present together, and for selenium as Se^2-, Se°, Se⁴⁺, and Se⁶⁺. Analytical results are presented for FeO in the range 0 to 0.25%; for total As and Sb as tri-oxide, 0.1 to 1.25%; and for total Se, 0.05 to 0.25%. Apparatus for the determination of FeO is described, and a comparison is made of analytical data for FeO versus light transmittance at 1000 and at 1050 mμ for the same glass.     

Mathematical Modeling and Simulation of Drying Using Two Industrial Concurrent and Countercurrent Rotary Dryers for Ammonium Nitrate

Drying of ammonium nitrate (AN) is accomplished in the Shiraz Petrochemical Complex (SPC) using a concurrent rotary dryer following a countercurrent rotary dryer. A mathematical model for these rotary dryers including heat and mass transfer was developed. The model was checked against industrial-scale data, which showed a good agreement. The average absolute deviation of the simulation results compared to the industrial data for the concurrent dryer was 4.0% for solids moisture, 1.3% for solids temperature, and 1.8% for air temperature and for the countercurrent dryer it was 9.0% for the solids moisture, 2.0% for solids temperature, and 4.6% for air temperature. These simulation results reveal that for outlet solid moisture, inlet AN moisture, and air temperature as well as the outlet temperature of product, the inlet solid and air temperature have major effects for both concurrent and countercurrent flow.     

汽车工业用粘接材料的现状与展望

本文按照汽车制造工序介绍国外汽车工业折边用胶粘剂、点焊胶接用胶粘剂、车身密封胶、车身底涂料、窗玻璃用单组份湿气固化型聚氨酯胶粘剂以及纤维增强树脂用结构胶粘剂等主要胶种的最新技术发展动向。讨论了我国汽车工业用胶粘剂的现状和差距，提出几点建议。     

A control system for gas-dynamic flows in tunnel furnaces

A system has been developed for choosing the parameters of gas and air flows for tunnel furnaces for various purposes. An algorithm has been devised for controlling a system for selecting the hot air from the cooling zone for the dryer and for differential transfer of atmospheric air through special throttle packings in the cooling zone in order to reduce the level of thermal shock on components and normalize the gas-dynamic parameters of the working channel.     

Oil and water analysis of sunflower seed by near-infrared reflectance spectroscopy

The applicability of NIR for oil and moisture analyses of sunflower seed was determined using a NIR spectrocomputer system. The method was compared with the wide-line NMR method for oil analysis and with the A.O.C.S. oven method for moisture analysis. The NIR was calibrated with 120 samples for oil (96 for calibration, 24 for prediction) and 63 samples for moisture (55 for calibration, 8 for prediction). Twenty-two sunflower seed samples were analyzed for oil and moisture by NIR and by methods used by industry. The oil contents of the samples by NMR and NIR were not significantly different. The overall mean oil contents and mean of the standard deviations for the samples were: NMR, 44.2%±0.35% and NIR, 44.34%±0.74%. A significant difference was found between the moisture values obtained by the oven-drying method and NIR. The average standard deviation for moisture by NIR was 0.57% compared with 0.07% for the oven-drying method. The variability of the oil content in one of the commercial seed samples was 1.52% oil as determined by NMR and 2.52% as determined by NIR. The advantages and disadvantages of both methods are discussed.     

Extraction of rapeseed,linseed, safflowerseed and tobaccoseed with a new laboratory extractor

In this study, extractions of rapeseed, linseed, safflowerseed and tobaccoseed have been conducted with a new extractor which has been developed for the extraction of vegetable tannins and which was later applied to sugar beets and sugar cane. Using the optimal conditions of the new extractor for oilseeds, that is, 315μ particle size and 62 C temperature, technical hexane has been employed, and the variations of the rate and distribution of oil extraction from solid materials have been determined. Optimal extraction periods with the new extractor were found to be 88 min for rapeseed, 90 min for linseed, 118 min for safflowerseed and 90 min for tobaccoseed. The same seeds have been extracted with the Soxhlet extractor for a period of 10 hr. Soxhlet extractor yields compared to Gülbaran yields with the new extractor were found to be only 98.18% for rapeseed, 98.15% for linseed, 97.79% for safflowerseed and 97.39% for tobaccoseed.     

Shape normalization of catalyst pellet

A shape normalization, which is applicable in the entire range of Thiele modulus φ, is developed. A shape normalization established here for small φ and the shape normalization already established here for large φ are used in developing the normalization for all φ. This normalization brings the η - φ curves for all pellet shapes to a single curve corresponding to infinite slab geometry for all φ. The effectiveness factor for any shape of catalyst is simply the effectiveness factor for an infinite slab when the Thiele modulus for the slab is properly defined in terms of the characteristic pellet length and the reaction kinetics. The shape normalization is shown to give negligible error for any pellet configuration and first order reaction, and is postulated to hold for general kinetics and any pellet configuration, by proper definition of the Thiele modulus.     

发展甲醇 实施碳铵企业产品结构调整

概述了碳铵企业进行产品结构调整的迫切性。叙述了碳铵企业产品结构调整的方案,介绍了主体系统实施改造的技术以及有关回收气体和甲醇、氨延伸产品的生产技术。