共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
研究了用双螺杆挤压工艺混合固体推进剂药科过程中机筒温度、螺杆转速、螺杆混合元件及组合结构对推进剂药科混合段度的影响,认为第一段机筒温度、螺杆转速和螺杆混合元件及组合结构对产品混合优度有明显的影响。 相似文献
3.
导言 众所周知,挤压温度是热塑性聚合物挤压过程中的主要因素。外观和物理性质是加工者力求加工工艺最佳化的两个重要参数。挤出物的性质和形态沿着挤出螺杆的变化为挤出温度的函数仍是我们了解挤压过程和物理性质研究的一个新观点。对所加工产品测定其动态力学性能、物理性质和形态,对理解最终产品的分子运动和流动性是有效的,但是这种分子的流动性怎样得到以及在挤压过程中沿着挤出螺杆如何改变这方面的内容还没有过报导。 相似文献
4.
利用电磁感应辅助加热挤压膨化机对植物秸秆进行了膨化加工试验。研究结果表明:电磁感应辅助加热挤压膨化机利用高频转换器产生的高频电流,从而达到控制挤压膨化温度的作用。一级电磁感应加热,预热植物纤维,控制温度在80~110℃,二级电磁感应加热,为秸秆挤压膨化加工提供稳定的高温高压条件,控制温度在250~300℃。膨化量可达到200~400 kg/h,膨化产品粗纤维含量下降30%~50%,无氮浸出物含量在20%以上,代谢能提高近10倍。电磁感应辅助加热挤压膨化技术研究为形成工业化规模的秸秆膨化加工利用奠定了良好的基础。 相似文献
5.
6.
北京化工大学和吉林石化公司研究院采用螺杆挤压脱水膨胀干燥一步法干燥稀土异戊橡胶,考察了机头温度、机筒温度、机头压力和螺杆转速对产品质量和生产能力的影响。确定了最佳工艺参数:螺杆转速为80~90r·min-1,机头温度为150℃,机筒温度为160℃,机头压力为14~16MPa。在最佳工艺条件下,装置运行和工艺参数控制平稳,干燥后稀土异戊橡胶挥发分含量小于1.0%,门尼黏度降幅小于10%,能够满足产品应用的要求。 相似文献
7.
《化纤文摘》1998,(4)
984196挤压纺丝的挤压机及螺杆的设计Diekmeiss F.…;Asian Textile Journal,1997,(5),p .67一73(英)使用单螺杆挤压机,可以达到高的生产能力,使纤维达到一定的质量,还能提高产品的经济效益。厂商在选择挤压机时,应该考虑到要加工的聚合体,希望达到的生产能力,以及要求达到的熔体的质量。螺杆的设计能极大地影响到熔体的质量,并影响熔体的运送能力。对螺杆要求应该在维持熔体足够均匀性的前提之下,才考虑提高其生产能力;要求达到希望的产量,还要使熔体温度保持在精确的范围,并且螺杆应有良好的耐磨性能。有15篇参考文献。(林求德)螺杆挤压… 相似文献
8.
9.
通过CFD仿真技术,应用MRF和滑移网格模型对双基发射药螺杆挤压成型过程进行数值模拟。由于塑化后的发射药属于假塑性流体,模拟中通过UDF引入发射药表观黏度系数的实验数据,采用层流模型模拟得到了发射药在螺杆挤压装置内瞬态和时均的流场信息。模拟结果分析显示,采用文中设计的螺杆结构,在设计工况下挤压孔口流速分布均匀,其值随时间变化幅度较小,可以保证双基发射药稳定地挤压成型,成型截面较为规则。运行中螺杆根部存在负压区对螺杆的功耗和振动都会有一定影响,可以通过调整料斗位置和料斗内螺旋导板的旋向加以改善。螺杆表面受力以压力为主,静压强的最大值比表面切应力大了2个数量级。 相似文献
10.
利用门尼粘度计、红外光谱仪、凝胶渗透色谱仪和乌氏粘度计的测试数据对比了烘箱干燥法和螺杆挤压脱水膨胀一步干燥法得到的异戊橡胶的结构性能,通过拉力实验机、邵氏A硬度计的测试数据对比了2种方法干燥的异戊橡胶的机械性能,探讨了螺杆挤压脱水膨胀一步干燥法对异戊橡胶结构性能和机械性能的影响,实验结果表明,螺杆挤压脱水膨胀一步干燥法会引起异戊橡胶相对分子质量、门尼粘度和特性粘数下降,对异戊橡胶顺1,4-结构含量和机械性能没有影响,螺杆挤压脱水膨胀一步干燥法理论上可以作为异戊橡胶工业化特别是异戊橡胶中模试选用的干燥方法。 相似文献
11.
着重介绍日本新型双螺杆挤出机的最新研制和开发的机型,评述新型双螺杆挤出机的特点,特别是新近开发的SCR双螺杆挤出机、BIVOLAV双螺杆挤出机、HTM双螺杆挤出机、TEX双螺杆挤出机、高剪切型双螺杆挤出机、格子形叶的双螺杆挤出机、新AP型双螺杆挤出机的结构、性能及其应用,提出今后双螺杆挤出机发展前景及方向。 相似文献
12.
Venkatesh Abhijit Thunberg Johannes Karin Sahlin-Sjövold Rigdahl Mikael Antal Boldizar 《Polymer Engineering and Science》2020,60(5):956-967
To investigate the impact of process design factors such as number of passes, screw design and screw type, a poly(ethylene-co-acrylic acid) and a masterbatch containing 40 vol% nanocellulose were compounded using a twin-screw extruder with two different screw configurations. The 20 vol% composite pellets obtained, containing nanocellulose of different morphologies, cellulose nanofibrils and cellulose nanocrystals, were re-extruded several times to study the effect of re-extrusion. The compounded pellets were extruded into films using a single-screw extruder. These films contained aggregates of the nanocellulose material, which was reduced in size upon re-extrusion leading to an improvement in properties of the composites. With the best combination of process factors, the Young's modulus and stress at break of the composites increased by factors of 10 and 1.6, respectively. The presence of a strong network of the cellulosic entities was observed qualitatively using melt rheology upon re-extrusion. Re-extrusion had a negligible effect on the crystallinity of the composites. POLYM. ENG. SCI., 60:956–967, 2020. © 2020 The Authors. Polymer Engineering & Science published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers. 相似文献
13.
锥形双螺杆挤出机是塑料加工的一种重要机型。对SJSZ-55锥形双螺杆挤出机的螺杆进行了设计,研究结果可以指导同类螺杆的设计。 相似文献
14.
The US Department of Energy wants to replace 30 % of transportation fossil fuel with biofuel by 2025. A viable biomass pretreatment method might be found through extrusion. Extrusion pretreatments show a significant improvement on sugar recovery from different biomass feedstocks. However, glucose and combined sugar recovery from extrusion pretreated switchgrass was less than 50 %. Extrusion combined with other pretreatment methods could improve sugar recovery from switchgrass. Low‐concentration alkali acts as delignification agent without degrading the carbohydrates. In order to evaluate the combined effect of alkali soaking and extrusion, switchgrass samples of different particle sizes were soaked at different alkali concentrations for 30 min at room temperature and then extruded, using a lab‐scale single screw extruder at various barrel temperatures and screw speeds. Statistical analyses confirmed that all the independent variables considered had significant effect on sugar recoveries. The optimum pretreatment conditions resulted in a maximum combined sugar recovery of 88 %. 相似文献
15.
16.
借助SPSS统计分析软件,以主机螺杆转速和加料量为自变量建立了啮合同向双螺杆挤出机功率消耗的二元线性和非线性数学模型,探讨了主机螺杆转速和加料量对挤出机功耗的影响。通过实验得到的数据和模型预测数据进行对比。结果表明,二元线性回归模型完全可以用来对挤出机功耗进行预测。 相似文献
17.
Chris J. Rauwendaal 《Polymer Engineering and Science》1981,21(16):1092-1100
Twin screw extruders can he classified according to their geometrical configuration. The main distinction is made between intermeshing and nonintermeshing extruders. Another distinguishing characteristic is the sense of rotation. The most important characteristics of the various twin screw extruders are examined, with particular emphasis on the effect of screw geometry on the conveying characteristics. A brief review is given of the state of the art in theoretical analysis of twin screw extruders. Experiments with two lab scale, intermeshing twin screw extruders are described, one co- and one counterrotating. Results are presented on power consumption, residence time distribution, and mixing characteristics of the two extruders. The counterrotating extruder exhibits a narrower residence time distribution and better dispersive mixing capability. The corotating extruder showed a better distributive mixing capability. These results can be explained in terms of the conveying and mixing mechanisms in both extruders. The overall extruder performance seems to be dominated by the effect of the intenneshing region. Any realistic, theoretical analysis of twin screw extruders should be centered around the flow behavior and mixing characteristics of the intermeshing region. The corotating extruder appears to be best suited for melt blending operations, while the counterrotating extruder seems to be preferred in operations where solid fillers have to be dispersed in a polymer matrix. 相似文献
18.
19.
在介绍了啮合同向双螺杆挤出机特点的基础上,对其在生物降解淀粉塑料加工工艺中的关键问题——螺杆组合进行了探讨,结合双螺杆挤出机每个功能段的作用提出了螺杆最佳组合原则。 相似文献
20.
采用啮合同向旋转的双螺杆挤出机作为主反应器,半连续化直接缩聚法制备了聚对苯二甲酰对苯二胺(PPTA)浆粕.结果发现,较低的预缩聚反应温度有利于得到高相对分子质量的PPTA浆粕;而在双螺杆挤出机中主反应温度则应控制在70℃左右为宜;物料在双螺杆中的停留时间超过3 min,才满足制备PPTA浆粕的工艺要求.螺杆的转速对PPTA 浆粕的相对分子质量的提高不显著,若转速太快,使物料在双螺杆中的停留时间缩短,反而不利于得到性能较好的PPTA浆粕.本研究为直接缩聚法制备PPTA浆粕的进一步放大打下了基础. 相似文献