【作者】 崔静；

【导师】 吕柏源；

【作者基本信息】 青岛科技大学 ， 化工过程机械， 2011， 硕士

【摘要】 生胶塑炼是橡胶质品其它生产过程的基础。传统的间歇塑炼存在质量不均匀的问题。开炼机塑炼法自动化程度低、生产效率低;密炼机设备造价高,占地面积大。人们不得不寻求新的、更先进的技术来解决塑炼过程中所出现的问题。塑炼的焦点逐渐转向连续生产。螺杆塑炼机实现了操作的自动化、连续化,但由于排胶温度较高,并且塑炼胶有严重的“夹生”现象,限制了螺杆塑炼机的应用推广。这种现象的原因主要有以下几点:①机筒翻胶刀设置的不合理:胶料在此受到撕裂、摩擦作用产生大量的热量,导致温度升高,甚至出现过炼现象;②螺杆设计不合理:传统的塑炼螺杆采用普通螺纹,没有塑炼元件,生胶由喂料口加入后并未经足够的塑炼就由机头直接挤出,故而出现“夹生”现象;③喂料装置的不合理:采用气缸强制推胶,使得胶料在此产生大量变形热而升温;④强制冷却装置的不合理设置:采用冷却水对机筒冷却,造成胶料粘度增大,从而使摩擦作用更加剧烈反而导致温度的升高;⑤机头阻力过大使胶料摩擦升温。针对以上存在的问题,我们开发出一种新型连续塑炼设备——橡胶单螺杆连续塑炼挤出机,从而得到连续高效、质量均匀稳定的塑炼胶,进一步为橡胶连续混炼技术及装备的实现做好铺垫。本课题符合高性能低成本的发展要求,可以实现提质降耗,这将突破上述生产中的技术难关,推动炼胶工艺及设备的进步。在《橡胶连续塑炼设备的设计研究》课题中,重点所做工作和获得成果如下:1、本文首次设计了特殊的销钉机筒结构,采用“水滴型”销钉对生胶进行强力剪切,一方面使生胶得到剪切分流,将生胶切割成小块,从而实现有效的塑炼;另一方面,“水滴型”销钉一改传统的螺杆塑炼机的翻胶刀依靠弹性形变来分流胶料的方式,阻力明显降低,而实现了低温剪切。2、本文设计的螺杆首次采用复合型螺杆对生胶进行塑炼,通过对螺杆各参数的理论分析以及螺杆构型的合理设计,采用了结合低剪切分流型构型的锥螺杆。其一,锥螺杆有利于提高螺杆根部承载能力,并有利于建立稳定的压缩比,提高了生产的稳定性;其二,低剪切螺纹进一步加强了螺杆机筒系统对胶料的塑化水平。总之所选用的新型螺杆对降低排胶温度、实现低温挤出、得到高质量高效的塑炼胶起着至关重要的作用。3、在本设计中,喂料段采用了螺旋啮合喂料装置,保证了块状生胶连续稳定的喂入,同时为胶料提供强有力的推力,有效地增加了胶料的挤出压力,没有明显的升温,为提高挤出机生产能力和低温挤出提供了有利保证。4、在本设计中,采用恒温热水循环技术对橡胶塑炼过程进行温度控制。热水循环温控装置的使用有效的保证了胶料的温度恒定,实现了胶料性能的稳定,保证了塑炼胶的质量,同时为技术人员提供了高效简便的控制方法,降低了操作人员的劳动量。5、在本设计中,合理设计了机头,并结合有限元分析软件ANSYS对机头胶料的流场进行了模拟,优化机头设计,进一步加强了胶料的塑炼效果,保证挤出塑炼胶的形状的稳定性。综上所述,橡胶单螺杆连续塑炼挤出设备具有广泛的开发和应用前景,相信将会带来明显的经济效益和社会效益。更多还原

【Abstract】 Natrual rubber mastication is the foundation of other production process. In the traditional intermittent mastication, rubber is unevenly masticated. The open mixer is is not efficient and not automatic. The internal mixer with large floor space costs much. Consequently, we have to seek more advanced technique to solve the problems above. Gradually, it turns to continuous production. Although it comes to the automatically and continuously operating by the single-screw extruder, but the application of single-screw mastication extruder is restricted, because there is“half-baked”phenomenon, and the temperature is too high. As a result, the popularization of the machine is limited. There are many reasons for these phenomenons in the single-screw mastication extruder, it includes 5 points:①irrational knife in the barrel: rubber is teared and chafed and produces a lot of heat, which leads to a temperature rise and even over-refining;②irrational screw designing: plain screw thread without mastication element is adopted. Consequently, raw rubber is piled out without enough mastication, which leads to“half-baked”phenomenon;③irrational feeding installation: rubber is drove by an air cylinder which results in large deformation and heat;④irrational cooling systems: barrel is cooled, while it turns out just the opposite, the viscosity goes up higher, which in turn leads to fierce friction and temperature build-up;⑤the flow resistance is obstinate, which causes friction and temperature rise.In view of existing situation, we propose a new rubber contionuous mastication machine—rubber single-screw mastication extruder, which provides smooth and steady unvulcanized rubber continuously and efficiently, and which will realize continuously mixing technique in the future and solve the problems better. The machine designed in this paper will improve the quality, reduce the costs and energy consumption, which will break down the technical barrier, resolve the key technical problems above, and promote technological process. In this thesis—rubber continuous mastication machine, the main works include:1、In this thesis,the special pin is applied firstly in the mastication machine. On one hand,“drop point”pin is adopted to provide powerful shearing action for natrual rubber and cut it into small cubes, which will lay a sound foundation for mastication; on the other hand, traditional pins depending on elastic deformation are replaced, which decreases the resistance and realizes low temperature shearing.2、In this thesis,mixed mode screw is adopted firstly to raw rubber mastication. Characteristics of screw parameters are theoreticaly analyzed in detail, and overall designing of the screw is carried out. The special cone-shape screw is combined with new fashioned short shear cut technology. Firstly, the root load capacity of the screw is enhanced by using the cone-shape screw; and the production capacity is improved as well; secondly, short shear cut screw thread adopted in the fluxing zone redoubles the level of mastication. Hence, the screw designed in the thesis makes valuable contributions to reduce the temperature of unvulcanized rubber and to realize low temperature squeezing. And it is essential for receiving high-quality and high-efficiency unvulcanized rubber products.3、In this thesis,meshed spiral feeding device is introduced in the feeding segment. As a result, continuously and stably feeding of natrual rubber bulk materiel without significant temperature rise is guaranteed. At the same time, forceful thrust is produced, which is operative for squeezing press. The device provides advantaged base of raising the production capacity and low temperature squeezing.4、In this thesis,a most up-to-date generation of high efficiency energy saving heat exchange facility is adopted for the temperature control. It keeps the temperature constant, brings about stable properties for rubber, and improves the quality of the mastication goods. Besides, it offers the technologist a simple, easy operated technique with high efficiency as well. What is more, it cuts down the difficulty and intensity and improves their efficiency.5、In this thesis, the nose is designed rationally. With ANSYS finite element method, flow field and pressure analysis of handpiece are optimized,which further enhances mastication effect, and maintains the shape and squeezing output stable. In summary, there is a very bright future for the development and application of rubber single-screw continuous mastication machine, which will bring us both significant economic and social benefits.更多还原