NB-500AMS焊机在石油化工行业的应用及焊机特点

为配合国家西气东输工程而新研制成功的NB - 5 0 0AMS焊机一机多用 ,具有输出平特性和下降特性。逆变技术在焊接电源中广泛应用 ,对国民经济具有重要意义。     

PE管材焊接技术与应用

PE管材连接方法包括热熔焊接、电熔焊接;热熔焊接要求热熔焊机的操作要符合操作规范,电熔焊接要注意每个电熔焊机的电流和焊接时间,另外管件的焊接参数每个生产厂家不同,焊接参数也不同,不同PE级别的产品焊接只能电熔焊接。     

用DMM诊断逆变焊机的故障与修复

根据逆变焊机的故障性质和类型,介绍了用DMM检修逆变焊机的方法和步骤,同时结合案例说明逆变焊机的故障判断和维修过程。     

锆制容器筒体环焊缝焊接方法探讨

本文根据锆材的焊接特点,采用几种焊接方法进行了焊接试验和对比分析,对等离子焊机做了局部改装,设计并制作了专用保护工装,结合锆材的焊接性能和自动等离子焊机的特点确定了焊接工艺参数,实现了对大型锆、镍基合金容器筒体环焊缝自动焊接。     

寄生电容对高频除尘电源特性的影响

高频静电除尘设备在实际工作中由于电路工作在高频,加之变压器变比很大,使得变压器寄生参数对高频除尘电源供电特性的影响不可忽略。为此,通过对电流断续模式下,串、并联谐振变换器在不同工作阶段的数学分析、推导和归一化处理,得到高频除尘电源变换器的输出平均电流特性、开关管导通时间特性和临界断续频率特性,并以图形曲线的方式给出了量化分析结果。仿真结果证实了特性曲线的正确性和调频调压控制方案的可行性。     

焊机质量控制对聚乙烯燃气管道行业的影响

根据送检的热熔焊机和电熔焊机年度检验情况,分析了聚乙烯燃气管道用热熔焊机和电熔焊机质量现状,介绍了控制焊接工艺参数的主要性能指标的情况;探讨了焊机质量对焊接质量控制、施工工程、焊接工艺评定以及管道元件制造等方面的影响。目前国内PE燃气管道用焊机的性能水平参差不齐,直接影响管网连接质量和安全运行,同时对施工工程、焊接工艺评定工作开展和管道元件制造工艺水平有不可忽视的影响。认为应加强焊机质量监管,确立相关的法规和标准,执行规范的型式检验和定期检验制度,促进PE燃气管道行业的有序发展。     

交流弧焊机节电方法

通常情况下交流弧焊机合上开关接通电源后，无论焊接与否，一次侧线圈总有电流通过，空载时功率因数只有０２，使用时也只有０４～０５，线路损耗大。在不焊接期间切断交流弧焊机一次侧电源，就可消除弧焊机全部的空载损耗，节电效果比较明显。为此制作了交流弧焊机节电装置它分为移动焊接和固定地点焊接两种。１移动焊接装置移动焊接材料：接触器１只要求有１对触头和线圈完好、微开关１个及导线若干。移动焊接工作原理及其接线见图１。图１移动焊接原理图将微开关固定在焊钳手柄上，焊接时，合上刀开关ＤＫ，手握电焊钳手柄，可随时将微开…     

电弧螺栓焊及其在大型LNG储罐建造中的应用和焊接质量控制

电弧螺柱焊是一种在螺柱端部与工件表面之间产生电孤,在工作和螺柱端加热形成熔化层,在压力作用下将螺柱端部浸入熔池,并将液态金属全部或部分挤出接头之外,从而形成牢固连接的焊接工艺方法。与焊条电弧焊相此,电弧螺柱焊具有可实现全截面焊接、速度快、质量再现性好等特点,在LNG储罐植焊钉的焊接中广泛使用。结合国内某液化天然气接收站场16万立方LNG储罐工程建设实际,对电弧螺柱焊特别是常用的带陶瓷套圈拉弧螺柱焊的原理、焊接材料、焊接参数、焊工资质、焊接工艺评定及焊接质量控制等进行阐述。     

玻纤增强热塑性复合材料超声波焊接方法研究

基于对ECR玻纤增强热塑性复合材料的力学和热物理特性以及普通工程塑料超声波焊接理论的研究，借鉴普通工程塑料超声波焊接方法，提出了超声波焊接ECR玻纤增强热塑复合材料制件的新思路；探讨了超声波在ECR玻纤增强热塑性复合材料中的传播及焊接机理。通过调整超声时间、保压时间、焊接压力等工艺参数，使用普通超声波塑料焊机成功焊接了ECR玻纤增强PA66试件。力学性能测试和断口微观组织观测表明，试件焊接区结合良好。     

数字式UPS逆变器复合控制系统设计

提出一种基于TMS320LF2407的数字化UPS逆变部分的设计方法,采用PI控制和重复控制相结合的方法设计电压、电流双闭环数字控制器,给出设计过程及软件流程。     

反应堆压力容器主管道焊缝射线检查设备控制系统的设计与实现

针对核电站的特殊情况,设计了反应堆压力容器主管道焊缝射线检查设备控制系统,给出了该系统的硬件结构和软件实现方法。经验证,该系统能够稳定、快速并且高精度地到达焊缝位置,效果良好。     

Relationship of welding technology to degree of plasticization in the PVC films

The influence of the degree of plasticization on optimum heat-sealing or high-frequency welding conditions has been studied for plasticized PVC films with different quantities of DOP plasticizer. Two equations were obtained that relate the parameters of the welding process (time and temperature, or time and specific anodic current) with the degree of PVC film plasticization. The equations allow calculation of welding conditions needed to obtain maximum strength of welded joints. One describes the durability of lap joints; the other of T-joints.     

Flat-bed Printing of Carpet Squares by Vacuum Press Techniques

The market for domestic carpet tiles in the UK is currently fairly small, amounting to 2% of the total carpet market, but it is expanding. Printed carpet squares, co-ordinated with plain colours, are helping to increase design and colour flexibility and to further establish carpet squares as a viable floorcovering for the home. This paper discusses a flat-bed vacuum-transfer process for printing carpet squares. Basic machine parameters are described and the process limitations assessed against the machine's unique advantage of being able to produce print/tile registration. The further prerequisites of base fabric requirements and the various techniques available for paper printing are also examined.     

Relationship of welding technology to degree of plasticization in the PVC films

The influence of the degree of plasticization on the strength of the welded joints and technological parameters of high-frequency heat-sealing process is studied for PVC films with different quantities of di-2-ethylhexyl phthalate (DOP). The equation obtained relates the parameters of the welding process (time and specific anodic current) with the degree of plasticization of the plastic material. The equation allows calculation of the technological welding behavior to obtain maximum strength of welded joints.     

电焊动火过程中杂散电流对长输管道的腐蚀研究

采用杂散电流测量仪监测电焊动火过程杂散电流的变化情况,研究了电焊动火过程中管道及周围土壤中的杂散电流分布规律。结果表明,管道中的杂散电流由电焊点向管道两侧流动,杂散电流并不稳定,其变化范围很大,最大值与最小值相差几十倍;管中杂散电流随着离电焊点距离的增大逐渐减小,随着电焊机台数的增加逐渐增大,随着管道管径的增大,逐渐增大;同时在焊接过程中,土壤中的电位梯度相应增大,并随着离管道距离的增大逐渐减小。     

Vibration welding of thermoplastics. Part I: Phenomenology of the welding process

In vibration welding of thermoplastics, frictional work done by vibrating two parts under pressure, along their common interface, is used to generate heat to effect a weld. The main process parameters in vibration welding are the weld frequency, the amplitude of the vibratory motion, the weld pressure, and the weld time. How these parameters affect weld quality, the conditions that result in the best welds, the weldability of dissimilar plastics, and the effect of fillers such as glass are of interest. To address these issues, a research vibration welding machine in which all the parameters can be independently and accurately controlled and monitored was designed and fabricated. The phenomenology of welding, as determined by experiments on the four thermoplastics polycarbonate, poly (butylene terephthalate), polyetherimide, and modified poly (phenylene oxide), is described.     

变频器在注塑机调速系统中的节能分析及应用

运用变频器对注塑机进行节能改造设计,采用比例流量、比例压力信号动态控制变频器的输出频率,从而控制油泵电机的转速,实现变压节能。设计了变频器外部接口电路,进行了变频器参数设定和机电联调。经改造的注塑机系统的精度和稳定性极大提高,操作方便,节能效果明显,产生了显著的经济效益和社会效益。     

大型多级离心泵机组轴系的扭转振动分析

大型多级离心泵机组轴系的扭转振动特性直接关系到机组运行的稳定性与可靠性,为了分析带齿轮箱的高速多级离心泵机组的扭振振动固有频率及其影响因素,基于多体动力学分析软件ADAMS建立了机组轴系的虚拟样机模型,给出了轴系建模方法,分析了齿轮副和联轴器刚度对轴系固有特性的影响,基于API 610标准对最终设计的机组轴系扭振固有频率计算结果进行评定.结果显示机组轴系在工作转速附近存在多个固有频率,很有必要对机组轴系进行整体建模和分析,电机转子、泵转子和联轴器等对轴系的固有特性影响较大,通过适度调整泵轴和联轴器等结构可以使固有频率避开转子的工作频率.     

基于Device Net总线的造纸机传动系统设计

把现场总线Device Net应用到纸机控制系统中,通过硬件设计实现整个控制系统的PLC配线和与变频器的硬件连接,根据功能连接和总线通信的需要对变频器进行相关参数设置,并在此基础上对纸机控制系统的软件进行设计,实现纸机传动中加、减速等基本操作控制、速度链控制及负荷分配控制等功能.     

Analysis and Experimentation of a New Half-Bridge High-Frequency Resonant Inverter for DBD Type Ozonizer

The peak voltage across the dielectric barrier discharge (DBD) type ozonizer is a key factor for ozone synthesis, and it is hard to be kept stable in widely used high-frequency resonant inverters within the entire working range. The soft switching conditions of power switches in these resonant inverters cannot always be satisfied within the entire working range, too. To address the two questions, a new half-bridge high-frequency resonant inverter is proposed in the paper, and the expressions that accurately describe the behavior of the inverter are derived by analyzing different operating modes. The simulation and experimental results show that the peak voltage across DBD type ozonizer is kept stable, moreover, zero current switching of power switches is realized within the entire working range.