密炼室三维温度场分析

本文利用有限元法对密炼机混炼过程中密炼室的三维温度场分布进行了分析。重点分析了密炼室的三维温度场及其热量传递的分布情况,以及强制冷却对炼胶温度的影响,同时通过实验验证了密炼室温度场有限元模拟的正确性。     

串联密炼机组的研发和应用概况

介绍串联密炼机组的研发和应用概况。串联密炼机组由带压砣的上位机与不带压砣的大容量下位机组成,上位机采用低温转子,下位机采用啮合型转子。串联密炼机组可以实现从原材料投入到终炼胶产出连续一步完成,尤其适用于白炭黑用量大的胶料混炼,可提高混炼质量和生产效率,降低混炼能耗。大连橡胶塑料机械股份有限公司串联密炼机组的结构设计重点:密炼室和转子、传动系统、液压式压砣、冷却系统和过渡翻板门等;系统控制要点:密炼室温度和冷却效果、转子无级调速和压砣位置无级调整等。     

GK型密炼机混炼室装配工艺的分析

剖析了GK型密炼机关键件混炼室的装配工艺,分析了混炼室刃口与下顶栓斜面间隙处漏胶、漏粉的原因,并指出其改进思路。通过实例计算,指出原混炼室装配工艺中的不足之处,采取措施消除了不利的影响因素。经过不断优化完善,最后得到了一种新的混炼室装配工艺。     

密炼设备的几点改进

介绍了对F270密炼机上顶栓、140密炼机混炼室及进口11D密炼机的改进经验，取得了较好的效果。     

密炼设备的几点改进

介绍了对Ｆ２７０密炼机上顶栓、１４０密炼机混炼室及进口１１Ｄ密炼机的改进经验，取得了较好的效果。     

加工工艺对聚乙烯/乙炔炭黑复合材料中炭黑分散性的影响

采用表面电阻的统计分析、力学性能测试及扫描电镜分析等手段研究了不同工艺方法和工艺条件对聚乙烯/乙炔炭黑复合材料中炭黑分散性的影响。结果表明:与开炼工艺相比,通过密炼工艺制得的试样中炭黑的分散性更好;采用密炼工艺,转速为30 r/min,密炼5 min后出料,裁成小块投入混炼室再密炼5 min,制得的试样中炭黑的分散性最好;高转速、长时间的密炼工艺对炭黑聚集体结构有一定程度的破坏。     

生胶摩擦性能对密炼机工作的影响

由微观和唯象分析建立了橡胶粘附摩擦的理论模型。通过对模型的分析和试验验证,提出了提高密炼机混炼效果的新途径;（１）密炼机温度控制采用温水冷却,使密炼机处于最佳工作状态;（２）通过合理选择密炼室和转子表面材料以改变材料表面能来增大胶料与它们之间的摩擦力;（３）在压砣压力较大的条件下,在密炼室内壁沿与转子轴线同方向加工浅的光滑槽,可明显改善混炼效果。     

硫黄直接投入密炼机进行二段混炼

硫黄直接投入密炼机进行二段混炼在橡胶混炼工艺中，将硫黄直接投人密炼室与一段胶料进行二段混炼，可以提高混炼均匀性，提高混炼速度，改善生产环境，降低劳动强度。广州第一橡胶厂利用ＧＫ２７０Ｎ型密炼机的性能特点，开展了硫黄直接投人密炼机进行二段混炼的工艺试验...     

密炼设备的发展

橡胶密炼机会因混炼材料的侵蚀而受到损坏。个中原因是各种混炼材料对密炼室的装置有化学腐蚀作用。为了延长其使用寿命,可采用文中涉及的新材料和新的涂层。经多次试验发现,这些新材料和新的涂层可提高各装置的耐磨性和耐腐蚀性,从而达到延长密炼机的使用寿命之目的。     

逆混炼

逆混炼（upside down mixing），又称逆混、倒炼，是上世纪70年代出现的密机机一段混炼工艺的延伸，其加料顺序和传统顺序相反。在传统的炼胶工艺（无论开炼或密炼）中，都无一例外地先加生胶，然后再依次添加各种配合剂。逆混炼则反其道而行之，总的顺序颠倒成先加配合剂，后加生胶。即，首先加入各种助剂（硫黄、促进剂除外），混匀后再加生胶，然后再加压混炼。     

混合室直径对带喷射器的跨临界CO2热泵性能影响

通过在跨临界CO₂系统中引入喷射器是回收系统节流损失的有效手段。实验研究了混合室直径分别为1.2、1.4、1.6 mm时,对带喷射器的跨临界CO₂热泵整体性能以及喷射器自身性能的影响。整个实验中热水进口温度、蒸发温度不变,热水出口温度作为比较基准,在实验中为变量。结果表明,混合室直径对压缩机排气温度影响较小,而其对压缩机排气压力影响较大,当混合室直径为1.6 mm时,压缩机排气压力最小;当混合室直径为1.6 mm时,系统制热系数最高。     

橡胶混炼设备使用现状与工艺发展

分析了混炼设备的机型分类与对比,以及开炼机与密炼机的容量及功率比较。介绍了各种混炼设备的发展过程与现状,对比了各种混炼设备的特性、适用范围及性能参数。介绍了混炼室、转子及上下辅机的发展概况。最后展望了混炼设备的未来发展。     

压缩/喷射制冷循环中两相喷射器性能

考虑引射流体的壅塞现象和混合室内的凝结激波现象,对混合室采用恒面积混合模型,应用质量守恒、动量守恒和能量守恒对两相喷射器建立了热力学模型。以R141b为工质,研究了在不同混合压力条件下喷射器内的压力变化趋势,分析了混合压力对系统性能、喷射器喷射系数和出口压力的影响,探讨了喷射器最优引射室压降、系统最优性能系数及相应的性能提高率随冷凝温度和蒸发温度的变化情况。结果表明:在本文计算工况范围内,两相喷射器混合室内无凝结激波的发生;对混合室采用恒面积混合模型相比等压混合模型更合理;恰当选择混合压力对优化系统的性能非常重要,其最佳值略低于引射流体压力,而远高于引射流体的临界压力,且其对应于喷射器取得最高的喷射系数。     

A comparison of the effects of traditional and wet mixing processes of rubber on metal friction and wear

Prolonged operations of mixers cause wear of mixer rotors and chamber walls and affect the clearances between the rotors and chamber walls, which reduce the mixing effect, weaken the dispersion of the packing, and affect the quality of rubber products. In this study, the effects of traditional mixing and wet mixing on the friction and wear of the chamber, and the properties of rubber were compared by using 60 phr of a silica natural rubber formulation system. The results show that a silanization reaction occurs between silica and the silane coupling agent during the mixing process and that the reaction rate is fastest when the temperature of the mixing chamber is maintained between 145 and 155°C for 1 min during the mixing process. The products of silanization reaction are ethanol and water; the water vapor that forms at high temperatures corrodes the mixing chamber of the internal mixer and aggravates wear and tear. Due to the high dispersion of silica during wet mixing, the silanization reaction is more complete and water vapor is produced at a high temperature. Hence, the rubber compound obtained by wet mixing has more significant wear on the mixing chamber.     

Thermal and structural effects of poly(vinyl chloride)/(wood flour) compound gelation in the Brabender mixer

The processing of two unplasticized compounds of poly(vinyl chloride) (PVC) with and without wood flour (WF) was performed in a Brabender mixing chamber, at various chamber temperatures between 130 and 200°C and at a shear rate of 12.61 s^?1. The test was carried out up to the time corresponding to the equilibrium state of the torque, and the variations of torque and real melt temperature as functions of time were analyzed. It was found that the addition of WF led to fusion at lower chamber temperature and that during gelation, stronger self‐heating effects occurred in the WF‐filled PVC compound. Various characteristics of the real temperature gelation curves of PVC with and without the WF filler were observed and are discussed. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

UV fluorescence monitoring of the mixing of molten polymers in a batch mixer

A fluorescence monitoring device was developed to study the distributive mixing process inside the chamber of a batch mixer. A bifurcated UV‐fluorescence probe was implemented instead of the thermocouple measuring the temperature of the melt. Hydroxymethyl anthracene was used as fluorescence tracer and was preliminarily dispersed in the minor component. Furthermore, the main polymer of this study was a copolymer of ethylene and vinyl acetate (EVA). Structure development during mixing of miscible polymer blends, low viscosity ratio blends (plasticizer/polymer), and immiscible polymer blends was investigated by this method. It was shown that the mixing process of a miscible system depends on the shear rate, which governs the temperature of the melt and consequently the melting process of the solid masterbatch‐tracer at the early stages of mixing. On the other hand, the presence of a miscible component of very low viscosity, as, for example, mixing of DOP in EVA, delays the onset of mixing. This lubricant effect was shown to be due to the fact that DOP migrates to the wall of the chamber rather than inside the polymer, though it is well miscible with the EVA phase. The study of immiscible polymers, as, for example, polypropylene in EVA, did not show any fundamental difference with miscible polymer blends. This observation is actually inherent to the UV‐fluorescence tracer disperesed in a masterbatch system, which allows quantification of the distributive mixing process only.     

基于CFD的新型布浆器混合室结构

为了进一步改善新型布浆器的布浆性能,设计了单腔式混合室（混合室Ⅰ）、以两组支管为单位的多腔式混合室（混合室Ⅱ）及以单组支管为单位的多腔式混合室（混合室Ⅲ）,采用计算流体力学（CFD）方法对混合室内的流动特性进行了模拟。结果表明,单腔混合室内,由于平行射流组各股射流间的强烈干涉作用,导致各股射流向混合室中部聚集,造成出口处质量流量分布呈现中间明显高于两侧的状态。在多腔混合室Ⅱ内,每个混合腔内有两组射流,保证了浆料的良好混合,避免了射流在中部聚集的现象。在多腔混合室Ⅲ内,由于每个混合腔内只有一组支管射流,实现了互补混合过程,混合效果明显好于混合室Ⅰ和混合室Ⅱ。从质量流量分布看,混合室Ⅲ的分布曲线比混合室Ⅰ和混合室Ⅱ的更平缓,其最大偏差仅为0.254%,明显小于混合室Ⅰ的0.538%和混合室Ⅱ的0.294%,更接近于理论混合平均值和期望值。     

High‐Throughput T‐Jets Mixers: An Innovative Scale‐Up Concept

The influence of geometrical and design parameters of T‐jets mixers on flow dynamics and mixing patterns is studied by means of two‐dimensional computational fluid dynamics simulations, planar laser‐induced fluorescence, and test chemical reactions. The ratios between injector width and mixing chamber width and between width and depth of the mixing chamber were evaluated as parameters. These ratios determine the flow regime in T‐jets mixers: high values of injector/chamber width ratio favor mixing and high depth values also increase the flow dynamics and thus mixing. A strategy for scale‐up of T‐jets mixers is devised, based on increasing a noncritical dimension (depth) while keeping other dimensions small.     

Effect of adding different silane coupling agents on metal friction and wear in mixing process

The function of silane coupling agent in rubber mixing field is to combine inorganic matrix with rubber organic matrix. Silica is commonly used in the rubber mixing field to strengthen rubber. The size and amount of silica aggregates in the mixing process are important factors affecting the wear of the mixing chamber. The wear of the mixing chamber would lead to a increasing gap between the mixer chamber and the rotor, which caused the mixing efficiency reducing. It also affected the dispersion effect, then affected the mechanical and physical properties of the vulcanized rubber. In this paper, the effects of rubber compound on metal friction and wear were studied by using four silane coupling agents commonly used in rubber mixing field. The experiment was carried out at 15°C, and the attention should be paid to drying during sample preparation to avoid the deviation of the experiment caused by hydrolysis of silane coupling agent. The results showed that silanization reaction occured between silica and silane coupling agent in the mixing process. The mixing temperature was usually maintained at 145 to 155°C for 1 min in the mixer, and the silanization reaction rate was the fastest during this time. We took this rubber compound as the research object and studied the friction and wear of the rubber compound on the mixing chamber in the mixing process. The products of the silylation reaction are alcohol and water. This paper studies the corrosion and abrasion of the mixing chamber by water at high temperatures. In the mixing process, abrasive wear was the main wear form, but the corrosion wear caused by high temperature steam still occupied a large proportion.     

批量旋转混料机的研制及应用

介绍了批量旋转混料机的结构、性能与工作原理,以及正立方体混合室的翻转、推拉作用,使室内多组分聚合物在非熔融状态下的扩散,更换位置,以达到各组分混合物趋于均匀,即分布混合的目的。