跳管纱的成因及预防措施

细纱出现跳管纱,对下道工序会形成不利影响,造成浪费.究其原因:一是纱管与锭子配合不良.锭子弯曲、锭盘偏心、缺油、锭子轴承损坏、锭盘内有杂物、纱管芯子磨损或缺少、纱管弯曲变形、纱管振幅大等因素,都会形成纱管和锭子配合不良,造成跳管纱;二是锭子速度过高,由于纱管材质或内在结构不均匀引起的跳管;三是操作不良.落纱插管时出现高管,落纱工责任心不强,不及时处理,锭子缠回丝,清理不及时,出现跳管纱.针对以上跳管原因,我们制定了以下几条措施.     

塑料细纱管锭孔结构的研究

分析了细纱管跳管的诸多因素，用闪光测速仪和红外测速仪测试了管速与锭速，从纱管锭孔结构上作了改进。５年多使用改进后的纱管计纬纱管２０万只，经纱管３０万只，效果良好，纱管振幅合格率提高１０％。     

纱管的握持力和刚度

跳管问题是纱管生产和使用中永恒的话题,多年来人们对此进行了大量研究,对产生跳管的原因也提出了许多见解,诸如离心力说,纱线张力说、临界转速共振说等等;为解决跳管问题,也提出了许多改进措施,如研究塑料"合金"、改进工艺和管体结构等等。但人们关注的焦点最终归结为纱管的握持力和刚度及其与纱管运转状态之间的内在联系。本文以塑料经纱管为例,对此进行分析和讨论.     

纱管的握持力的刚度

跳管问题是纱管生产和使用中永恒的话题，多年来人们对此进行了大量研究，对产生跳管的原因也提出了许多见解，诸如离心力说，纱线张力说，临界围速共振说等等。为解决跳管问题，也提出了许多改进措施，如研究塑料“合金”，改进工艺和管体结构等等。但人们关注的焦点最终归结为纱管的握持力和刚度及其与纱管运转状态之间的内在联系，本文以塑料经纱管为例，对此进行分析和讨论。     

光电式纱管振幅检验机

一、概述纱管振动幅度的大小,是衡量纱管质量的重要指标之一。由于纱管的振动,使细纱机锭子尖端的磨损和动力消耗增大。振幅过大还会引起跳管,增加断头,造成坏纱,直接影响纺纱的质量和产量。纱管振幅大小的检验,长期以来全靠工人老师傅凭经验手感目测,这样不仅劳动强度大,而且由于各人感觉上的差异和技术熟练程度的不同,造成纱管振幅的测定既不准确又不科学。     

塑料经纱管改用PC芯眼

塑料经纱管的芯眼通常用热固性树脂(如酚醛树脂)制作。存在问题是:1.在高速运转情况下,纱管摆幅明显增大;2.如果芯眼和锭子配合较松,容易造成跳管;反之,若芯眼和锭子配合很紧,虽然防止了跳管,但拔管就很     

205塑料经纱管动态变形问题

一、概述 1979年下半年,我厂用西德拜耳公司的ABS塑料生产205经纱管。经纺织厂使用,普遍反映当锭速超过15000转/分时,断头增加,跳管严重,尤其是中纱以上产生跳管,一落纱占4～8％。     

木纱管变形规律的初步探讨

木纱管,特别是纬纱管,因为要与梭子配合使用,所以对纱管规格要求是严格的,例如项颈外径、管箍外径的公差只有0.2mm。我厂地处大陆性气候的华北地区,四季空气含水变化大,有时木纱管项径、底孔、管箍外径变形量高达0.3～0.4mm。因此,过去经常出现产品规格不稳,定位底孔忽高忽低、忽大忽小,也常出现箍裂及松动等现象,严重影响梭管配合。因此,我们从1973年开始摸索木纱管变形的规律,逐渐掌握了从成形到成品这一过程中不同季节变化的情况,从而找到合适的加工留量,保证了成品木纱管规格要求,使木纱管质量趋于稳定。     

影响塑料经纱管弯曲变形的探讨

塑料经纱管弯曲变形是纱管变形中的主要和常见的一种(还有下口变小、锭孔变形、管子扁等变形),它在纱管下注射机后和纱管长期存放、长期使用中都会发生。弯曲变形影响塑料经纱管的同心度,因而也就直接影响塑料经纱管的生产效率、使用寿命。     

浅谈纱管对成纱质量的影响

为了引起纺织企业对纱管使用及管理的重视,阐述了58纺纱对纱管的材质及制作精度的技术要求,总结纱管的日常管理经验,分析不合格纱管对细纱成纱质量的影响;指出纱管是重要的纺织器材,其与锭子是否匹配,直接影响锭、管的同轴度;应用优质纱管可提高成纱质量,减少消耗,增加效益。     

纺纱牵伸胶辊胶圈应用技术概要

阐述棉纺牵伸胶辊、胶圈的应用技术和牵伸原理,重点探讨了胶辊、胶圈的牵伸工艺特性及其合理配置、胶辊制作、周期管理、质量管理、使用管理、产品缺陷与其机械波分析、纺纱环境和挡车工操作水平对纺纱性能的影响,提出胶辊、胶圈有关机件的质量要求等。     

赛络纺纱钢领、钢丝圈的选配实践

为了提高赛络纺纱成纱质量,减少细纱断头,从钢领、钢丝圈的种类,卷绕过程中对纺纱的影响及其运动配合等诸多因素出发,论述了钢领、钢丝圈的选配原则,重点阐述了赛络纺纱钢丝圈运动形态的变化及钢领、钢丝圈的选配要求,通过纯棉、非棉纤维纺纱的选配实践,指出赛络纺纱线毛羽少,结构紧密,应根据纺纱纤维性能和纺纱特点,以纱线通道通畅降毛羽、运行平稳少断头、散热良好延长使用寿命为原则对钢领、钢丝圈进行选配。     

高校宝石及材料工艺学专业的构建研究

通过回顾高校宝石及材料工艺学专业的创建历程,深入探讨了该专业未来发展所面临的、深层次的理论问题,即学科属性与文化背景,学科构成与知识内涵,学科方向与实践定位,学科任务与社会功能。在此基础上,建立了多层次技术教育的社会功能模型,由此推断：高校中的宝石及材料工艺学专业属于多层次技术教育中的高等职业技术教育。同时,还构建了该专业的技术教育的社会功能模型和学科构成模型,进一步确立了该专业的社会实践定位。     

服装的空间形态辨析

从分析服装空间形态的构成要素入手,通过中西方服装空间形态的比较,阐述服装形态在空间关系上的相关问题,对服装的形态类型、要素构成和内外构成等方面进行了较详细的探讨和分析,印证了人类在同一服装原生状态基础上所产生的造型差异,是由于不同人对服装空间形态的认识方式和服饰审美观念存在差异所致。认为无论是东方式的平面构成或是西方式的立体构成,服装的形态都是在不同时代、不同地域和文化中被人们以不同的空间构成方式创造出来的。辨析服装空间形态及其构成方式,为现代服装的造型设计提供了一条丰富服装创意思维的现实途径。     

Human risk assessment and TEFs

The concept of toxic equivalency factors (TEFs) has been developed to facilitate risk assessment and regulatory control of exposure to complex PCDD, PCDF and PCB mixtures. Recently the European Centre for Environment and Health of the World Health Organization (WHO-ECEH) and the International Programme on Chemical Safety (IPCS) jointly reevaluated the TEFs of PCDDs, PCDFs and dioxin-like PCBs for mammals and derived consensus TEFs for birds and fish (Stockholm, 1997). From a mechanistic point of view it can be concluded that, although the quantitative response will vary depending on the congener involved, the occurrence of a common mechanism (binding to the Ah receptor) legitimates the use of the TEF concept across species. But there also is criticism regarding the TEF concept. Pharmacokinetic differences between species can significantly influence the TEF value, and uncertainties due to additive or nonadditive interactions, to differences in species responsiveness and to differences in the shape of the dose response curve might hamper the derivation of consensus TEF values. In this context it should be noted, however, that using TCDD alone, as the only measure of exposure to dioxin-like PCDDs, PCDFs and PCBs, would severely underestimate the risk from exposure to these compounds. Therefore, it can be concluded that, for pragmatic reasons, the TEF concept remains the most feasible approach for risk assessment purposes, in spite of the uncertainties associated with its use.     

39—THE FLOW OF LIQUID FROM A JET THROUGH A COMPRESSIBLE POROUS LAYER. PART III: THE CHARACTERISTICS OF LIQUID FLOW THROUGH A COMPRESSIBLE LAYER OF LOOSE WOOL

The effects on the conditions of flow of the surface and configurational properties of the fibres in a compressible porous layer are discussed. The characteristics of a layer of wool are evaluated, and its compressibility is determined. It is shown that, when a liquid of initial uniform pressure flows through a compressible porous medium, the pressure gradient within the medium increases with the distance of flow. The resulting pressure drop is found to depend on a function of the ratio of the downstream to the upstream porosity of the compressible medium. Experimental results are reported for permeable flow through various layers of loose wool; these indicate that, when the flow is disturbed turbulent, the pressure drop through the layers is proportional to the square of the filter velocity. This result is not readily apparent from the graphs of pressure drop against filter velocity because of the compressibility of the fibres.     

集体落纱快装纱管用铝杆锭子设计

为提高空纱管安装效率,分析集体落纱细纱机特点,介绍了锭子杆盘结构型式,说明目前国内铝杆锭子多采用支持器弹簧加支持器帽的结构,虽能基本满足集体自动落纱细纱机的生产需要,但仍存在机械手安装空纱管时动作较多、动作精度不高、且易撞到锭子问题,易对锭子造成损坏并缩短锭子使用寿命的缺陷,重点对新设计的快速安装纱管的铝杆锭子的结构及原理进行分析,指出将弹簧支持器帽换成钢珠,可以大大缩短集体落纱细纱机机械手安装空纱管时间、降低对机械手动作精度的要求,且不损坏锭子、不影响锭子使用寿命,实现了节能降耗、安装效率高的目的。     

11—AN INVESTIGATION OF THE AIR-JET BULKING PROCESS

Experiments aimed at investigating the mechanism of the air-jet bulking or texturing process led to an interesting observation that the textured yarn emerging from the venturi was rotating in such a way as would temporarily untwist the yarn while it was in the jet. The indication is that false-twisting (or untwisting) occurs owing to the vorticity of the turbulent air in the wake of the yarn feed needle that bifurcates the air-stream. The various yarn-processing conditions separately affect the amount of false twist inserted. There is evidence to show that the direction of the vortex, and hence of the untwisting action, is dependent on whether the angular displacement of the feed needle from its central position is in a clockwise or anti-clockwise direction. A suggested mechanism of the process based on the untwisting and retwisting of the overfed filaments offers an explanation for the characteristic locked-in loop structure of air-bulked yarns.     

Combined microscopic and dynamic rheological methods for studying the structural breakdown properties of whey protein gels and emulsion filled gels

The microstructural and large deformation rheological properties of model food gels were studied by performing notch propagation tensile testing on the gels using a tensile stage and observing changes in the microstructure of the gels during tensile testing using confocal laser scanning microscopy (CLSM). Heat-set whey protein (WP) gels containing either added sodium caseinate (NaCN) or sunflower oil droplets emulsified with WP or NaCN as the emulsifier protein were prepared in 0 or 50 mM NaCl. The WP gel structure strengthened in the presence of added NaCl and NaCN. The rheological properties of WP gels containing sunflower oil droplets emulsified with WP or NaCN were influenced by the NaCl concentration, oil concentration and extent of oil droplet aggregation in the gel or by the type of emulsifier protein used. During tensile testing, the notch length in all gels increased above a certain critical stress, leading to fracture of the gels through the notch. Also, the microstructural changes in the oil phase of emulsion filled gels subjected to tensile testing were influenced by the structural properties of the WP gel matrix and the proximity of the oil droplet to the fracture path.