冷冲压圆锥形无缝漏嘴成形工艺初探

漏嘴是拉制连续玻璃纤维铂铑漏板的关键部份,其作用是按照熔融玻璃液成形要求拉制所需粗细的单根纤维.漏嘴的几何形状、尺寸、加工精度、壁厚的均匀性以及漏嘴内表面的光洁度等,都会影响漏嘴温度的不均匀,从而影响拉丝作业的稳定及其使用寿命.因此漏嘴的制造方法至关重要.目前国内制造的铂铑7(PtRh7)合金圆柱状漏嘴其主要加工工艺有:(1)直管形有缝漏嘴,把轧制的PtRh_7合金片料卷成空心管,焊缝,经过多道拉模     

空心高强玻璃纤维空心度与漏嘴结构参数关系研究

本文采用漏嘴中套芯管的特殊结构的拉丝坩埚,在稳定拉丝工艺参数的条件下研究了空心高强玻璃纤维的空心度K与芯管内径Фxn、漏嘴内径Фzn等结构参数的关系,归纳总结出如下关系式K=3.83фXN6.62фZN-3.19.经过验证,此式可作为设计不同空心度的空心高强玻璃纤维拉丝坩埚漏嘴结构的参考依据.     

消除丝根玻璃润湿漏嘴外壁的尝试

1、丝根、玻璃润湿漏嘴外壁的调查在拉丝过程中,丝断飞后丝根呈羊角状反卷至漏嘴外壁,使其外壁被润湿,严重时还会润湿相应的漏嘴根部处的底板.这种现象我厂生产中时有出现,并在锆弥散漏板使用中较为突出.具体情况见表1和表2.     

防止煤塔漏嘴洒煤的措施

1存在问题装煤车司机每天进行从煤塔取煤然后到焦炉顶加煤的操作,当装满煤关闭煤塔漏嘴时,因司机不能直接瞭望到煤塔漏嘴的开关状态,必须到加煤车     

玻璃纤维对玻璃球质量的要求

一、玻璃球质量的基本要求玻璃纤维生产中,要使拉丝顺利进行,减少断头飞丝,就要求玻璃液在漏嘴出口处有稳定的成型条件.即漏嘴四周形成一个恒定的温度场和均匀的玻璃体,以保持各漏嘴下丝根有相同的成型粘度.为此,对玻璃球质量要有基本的要求.首先,玻璃球要具有相当好的化学均化质量.不仅要求玻璃球内没有或有很少的条纹.至少达到平板玻璃质量;而且不同批的玻璃球的化学成份的波动也要保持在极小的     

玄武岩纤维拉制过程的简化分析

分析了玄武岩纤维拉制的基本过程,应用特鲁顿拉伸定律和流体流动与传热原理,建立了玄武岩连续纤维拉制成形过程的简化数学模型,提出了数值模拟方法。在计算机上模拟研究了纤维拉力、漏嘴温度和半径等参数对纤维半径、纤维纵向温度和速度分布的影响,为纤维拉制过程的调控提供了基本数据。     

坩埚漏嘴冷却管钳型支架的设计改进

笔者于1989年6月设计改进了一套坩埚漏嘴冷却管钳型支架,扩大使用近50台炉位以来,效果很好,解决了我厂原螺杆升降悬臂式冷却管支架存在的稳定性差,升降螺杆长期在高温辐射下,氧化锈蚀,升降困难或卡住无法升降的弊病。     

国外异形玻璃纤维发展概况

异形玻璃纤维指的是断面形状为非圆形的玻璃纤维.玻璃纤维通常用底部带有许多圆形截面漏嘴的漏板或周壁开有许多圆孔的离心器制造,纤维断面呈圆形.在成纤过程中,即使玻璃流股原本并不十分圆,它也会借助表     

玄武岩连续纤维的制备

利用坩埚法制备玄武岩连续纤维。研究了玄武岩纤维的熔融过程和拉丝工艺以及玄武岩纤维的基本特性。结果表明:选择陕西略阳辉绿岩矿作为玄武岩连续纤维的原矿,采用分体式氧化铝氧化铬坩埚,高度为13 mm,孔径为4 mm,台阶式漏嘴纺制玄武岩连续纤维,最长能成形15 m,纤维直径为12．2μm。     

绿色玄武岩纤维成型的数值模拟方法

本文建立了玄武岩熔体在漏嘴中流动与传热的数学模型,借助Fluent软件对数学模型进行了求解,得出了数值结果,数值结果与实验数值结果比较吻合.同时进一步验证了数值方法用来处理玄武岩熔体内复杂流动和传热问题的可行性与预见性.为玄武岩连续纤维的成形提供了另外一种解决方法,为玄武岩连续纤维的成形工艺提供了新的实验数据和理论依据.     

新型(多喷嘴对置)水煤浆气化炉的开发

通过大型冷模和小型热模试验开发新型（多喷嘴对置）水煤浆气化炉,介绍了中试结果及其与德士古水煤浆气化技术的比较,并阐述了新型水煤浆气化炉的技术优势,结果表明,多喷嘴对置气化技术优于引进的德士古技术。     

涤纶POY接尾技术探讨

分析了涤纶POY接尾通过率的影响因素以及在接尾生产中存在的产品质量问题,探讨了新的冷拉伸接尾法,即接尾段在空气交络之前进行冷拉伸,或在空气交络之后再进行两端20 cm冷拉伸。对冷拉伸实施步骤进行了介绍。     

Melt spinning of poly(vinylidene fluoride) fibers and the influence of spinning parameters on β‐phase crystallinity

The effects of melt‐spinning and cold‐drawing parameters on the formation of β‐phase crystallinity in poly(vinylidene fluoride) (PVDF) fibers and ways of increasing such crystallinity were studied. Fibers were melt‐spun with four different melt draw ratios (MDRs) and were subsequently cold‐drawn at different draw ratios (λ). The maximum λ value in cold drawing was dependent on the MDR used in melt spinning. The crystalline structure of the fibers was studied mainly with differential scanning calorimetry (DSC) and X‐ray diffraction (XRD). The results showed that the degree of crystallinity in the fibers was determined by the MDR and that before cold drawing the crystalline structure of the fibers was predominantly in the α form. By cold drawing, α‐phase crystallites could be transformed into the β phase. It was established that, under certain conditions of melt spinning and cold drawing, PVDF fibers of up to 80% crystallinity, mainly in the β form, could be prepared. It was further proposed that fibers spun at a sufficiently high MDR consist to a large extent of extended‐chain crystals, and this greatly affects the melting point of PVDF. Thus, DSC melting‐point data were shown to be insufficient for determining the crystalline phase of PVDF. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Influence of nozzle geometry on ignition and combustion for high-speed direct injection diesel engines under cold start conditions

Starting at low temperatures (below 0 °C) is an important issue for current and near future diesel engine technology. Low ambient temperature causes long cranking periods or complete misfiring in small diesel engines and, as a consequence, an increased amount of pollutant emissions. This paper is devoted to study the influence of nozzle geometry on ignition and combustion progression under glow-plug aided cold start conditions. This study has been carried out in an optically accessible engine adapted to reproduce in-cylinder conditions corresponding to those of a real engine during start at low ambient temperature. The cold start problem can be divided in two parts in which nozzle geometry has influence: ignition and main combustion progress. Ignition probability decreases if fuel injection velocity is increased or if the amount of injected mass per orifice is reduced, which is induced by nozzles with smaller hole diameter or higher orifice number, respectively. Combustion rates increase when using nozzles which induce a higher momentum, improving mixture conditions. For these reasons, the solution under these conditions necessarily involves a trade-off between ignition and combustion progress.     

超高压水射流在电厂汽轮机叶片清洗中的应用

火力发电机组运行一段时间后,汽轮机叶片、隔板喷嘴都必须进行清洗,以保持机组运行正常和经济性。随着科学技术的发展,目前,电厂越来越多地采用超高压水清洗技术,而逐步淘汰一些老的清洗方法,以保护设备和环境。     

多喷嘴对置水煤浆气化炉的开发与应用

介绍多喷嘴对置水煤浆气化炉的实验室研究及中试情况,并与Texaco水煤浆气化技术进行了比较,结果表明,多喷嘴对置气化技术优于Texaco技术。     

Service of zircon nozzles for continuous steel casting

Conclusions The Chasov-yar Refractories Combine has introduced a technology developed by UNIIO for making zircon nozzles for continuous steel casting equipment. Zircon nozzles possess a high erosion resistance and give a more stable casting for killed and unkilled steels compared with other types of nozzle. Tightening of the nozzles when pouring killed steel depends on a number of factors (amount of reducing agent, casting temperature, chemical composition of the steel, refractory, etc.) and requires further study.T. M. Vysotskaya-Kvitko took part in the work.     

500 dtex/68 f聚酰胺6高强丝的生产设备与工艺

介绍了500 dtex/68 f聚酰胺高强丝的生产设备与工艺。在设备方面,对熔体管道进行特殊设计,采用2 500 mm长的侧吹蜂窝板,用双油嘴上油,喷丝板微孔采用环形排布,牵伸辊改为一冷三热等;在工艺方面,选择相对黏度为2.8~3.2的切片,纺丝温度270~280℃,开发适合高强丝的油剂,优化牵伸工艺等,生产出了满足客户要求的产品。     

干法高收缩腈纶短纤维生产工艺试验研究和纤维性能探讨

通过对高收缩腈纶短纤维一次牵伸、干燥及二次牵伸等工艺条件的试验与研究,指出了影响高收缩腈纶短纤维生产的技术关键,尤其对二次牵伸及其卷曲的工艺控制难点进行了分析,全面阐述了工业化生产高收缩短纤维的工艺过程,并对纤维性能及用途进行了介绍。     

Melt spinning of PVDF fibers with enhanced β phase structure

Polyvinylidene fluoride (PVDF) fibers with a high amount of β phase crystal structure were prepared by melt spinning. With this technique, the cold drawing process is critical and efficient when aiming for a high amount of β phase. During the cold drawing process, more than 80% of the originally formed α phase crystal structure was converted into the β phase structure. In addition, the incorporation of 0.01 wt % of amino‐modified double wall carbon nanotube (NH₂‐DWCNT) could further enhance the β phase content in the PVDF fibers. FTIR and DSC studies showed that the addition of NH₂‐DWCNT to PVDF fibers could increase both the total crystallinity and β phase fraction in PVDF. The addition of nanoclay was found to be less efficient in this respect. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2603–2609, 2013