涤纶长丝生产中喷丝板的选用

分析了涤纶长丝生产中喷丝板选用的相关理论 ,对熔体的切变速率、喷丝头拉伸比、喷丝板背压的计算方法进行分析讨论 ,认为 3个参数可作为选择喷丝板微孔直径和长径比的依据 ,并举实例进行了验证     

环形组合喷丝板清洗浸泡装置的改进

对喷丝板浸泡槽和喷丝板夹持器做了改进，喷丝板夹持器可固定28个环形喷丝板，夹持器送入浸泡槽和从浸泡槽中取出由电动操作替代人工操作，提高了工作效率和安全性、降低了劳动强度。     

特种塑料熔融法纺丝用喷丝板的结构分析

本文通过对特种塑料熔融法纺丝用喷丝板的结构作简要的流变学分析计算,初步提出这种喷丝板设计的主要技术参数,为进一步的生产制作提供了参考依据。     

喷丝板的设计

介绍了熔融纺丝所用喷丝板的材质、喷丝板形状、熔体在喷丝孔中的流变特征,喷丝板微孔几何形状重要参数,喷丝孔排列方式,开孔范围及孔间距,喷丝板的厚度。     

特种喷丝板

目前普通干纺和湿纺用的喷丝板,其毛细管孔径范围约为0.035～0.100mm,而熔纺的喷丝板,其精度和技术要求较高。特种喷丝板的技术难度和水平就更高了。以下仅介绍8种新型喷丝板的情况。 ①熔喷法喷丝板,长度达4米,孔数多达2万孔,用于纺制超细纤维无纺布。这种喷丝板要求实现最大的精度、喷丝孔的合理排列及喷丝板体的表面质量。     

喷丝板选型对涤纶长丝质量和生产需求的探讨

分析了涤纶长丝生产中喷丝板选择的理论依据与实际需求的关系,将选型的理论计算与实际数据进行比对,确定实际选型与理论计算值之间的偏好方向,为前期批量选型和后续新品开发选型提供一定的参考方向。     

聚酯纺丝中剪切速率与不同截面形状微孔的关系探讨

总结了高分子熔体通过异形喷丝板时其剪切速率的表征和计算,为不同孔形喷丝板的设计提供了一定理论依据。通过生产实践过程,分析了几种常用异形微孔形状其剪切速率的影响因素及变化规律,归纳出不同孔形的剪切速率的具体取值范围。     

喷丝板质量管理系统的研究

介绍了喷丝板质量检测方法现状,分析了现有的喷丝板质量管理处于单一、质量无法追踪等问题,设计出了一种喷丝板的质量管理系统,并对此质量管理系统的结构及工作流程进行了描述,表明该管理系统可实现喷丝板寿命的有效管理,同时可实现纤维质量的可追溯性。     

基于Labview的喷丝板检测仪控制系统

基于Labview软件设计了针对化纤用喷丝板微孔检测的喷丝板检测仪控制系统.系统硬件主要由工业计算机、三轴精密运动平台、运动控制卡、图像采集系统等组成.系统软件采用了NI公司的Labview作为开发平台,根据喷丝板微孔的特点设计了喷丝板的检测流程,包括喷丝板数据的导入、自动对焦、自动走位、图像采集、微孔图像处理和测量、不合格微孔处理以及结果数据库管理等.经过多次试验表明:该检测仪运行可靠,检测速度可达1 s/孔,有效地解决了喷丝板微孔的自动化检测难题.     

喷丝板挠度的建模及分析

根据喷丝板工作的固定情况和工作载荷类型建立了喷丝板弹性变形的数学模型,得出了喷丝板挠度方程并进行了求解。结果表明:设计参数相同时,SUS 304不锈钢和钽材质喷丝板在相同压力下挠度相差不大;喷丝板的挠度与压力成正比,与厚度三次方成反比,随半径的增大而增大,随无孔区半径(r)的增大而减小;以聚丙烯腈基碳纤维原丝的纺丝为例,在喷丝板材质为SUS 304不锈钢,其半径为30 mm,厚度为2 mm的条件下,湿法纺丝时,喷丝板的r大于2 mm,可实现顺利纺丝;干喷湿纺时,r大于6 mm,可减小内圈的掉胶,顺利纺丝。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。