沟槽机简单螺杆挤出机塑化性能的模拟研究

对传统光滑机筒单螺杆挤出机、固体输送段沟槽机筒单螺杆挤出机和熔融段沟槽机筒单螺杆挤出机的结构特点、输送机理、熔融热源以及熔融模型进行了对比分析,并对其熔融过程中熔融速率、熔融长度和熔融起始点进行了数值模拟,根据模拟结果分析了机筒结构形式对单螺杆挤出机熔融性能的影响。结果表明,机筒内壁开设沟槽的单螺杆挤出机在结构、机理和性能等方面均优于传统光滑机筒单螺杆挤出机,且将机筒沟槽由固体输送段延伸至熔融段对单螺杆挤出机的熔融性能有显著的提高。     

沟槽机筒单螺杆挤出机耦合双槽熔融理论研究

利用自制的液压剖分式沟槽机筒单螺杆挤出机实验平台,研究了沟槽机筒单螺杆挤出机的熔融长度和螺杆转速的关系,实验验证了单螺杆挤出机固体输送段和熔融段机筒均开设沟槽的耦合双槽熔融理论。结果表明,与传统光滑机筒单螺杆挤出机和IKV单螺杆挤出机相比,在熔融段机筒开设沟槽的单螺杆挤出机的熔融长度较短且熔融过程比较稳定,熔融效率得到较大提高。     

沟槽机筒单螺杆挤出机塑化特性的实验研究

采用剖分式机筒单螺杆挤出机实验平台,对熔融段沟槽机筒单螺杆挤出机塑化过程中熔融起始点、熔融长度、熔体温度/压力等塑化性能及产量进行了实验研究,比较了不同物料在不同工艺条件下对沟槽机筒单螺杆挤出机塑化特性的影响。结果表明,增大螺杆转速或提高机筒温度,塑化过程实际所需熔融长度增加,但对熔融起始点影响不大;熔融段机筒沟槽内熔体温度和熔体压力随螺杆转速增大无明显变化;随螺杆转速增大,沟槽机筒单螺杆挤出机挤出产量呈线性增加,表现出良好的挤出特性。     

开槽机简单螺杆挤出机的对比研究

针对轴向直槽机筒单螺杆挤出机和螺旋沟槽机筒单螺杆挤出机的结构、固体输送机理和优缺点进行了对比分析,并对其比产量和比能耗进行了对比实验研究.结果表明,通过正确的沟槽结构设计,可实现螺旋沟槽机筒单螺杆挤出机固体输送段的正位移输送,螺旋沟槽机筒单螺杆挤出机在比产量、比能耗等挤出性能指标方面均优于轴向直槽机筒单螺杆挤出机.     

沟槽机筒单螺杆挤出机固体输送产量的粒径模型研究

在分析机筒衬套沟槽槽深、螺杆螺槽槽深和加工物料粒径关系的基础上,建立了沟槽机筒单螺杆挤出机3种常见的固体输送段产量粒径模型,该模型可用于研究机筒衬套沟槽槽深、螺杆螺槽槽深和颗粒物料粒径对固体输送机理的影响并定量计算沟槽机筒单螺杆挤出机固体输送段产量。此外,通过不同的机筒和螺杆组合及不同粒径的原料在自制的在线模拟试验机上对该模型进行了验证和试验分析。     

一种能量动态平衡节能塑料挤出机

本实用新型塑料挤出机通过在机筒外安装的加热器外面设置保温层的结构来达到能量动态平衡节能的效能。而且，在机筒外安装的加热器外面不再置备现有以单螺杆方式的普通塑料挤出机通常所采用的冷却风机，大大减少了现有普通塑料挤出机由于在机筒外加设冷却风机所导致的热量的散失和在机筒外安装的加热器所产生的热量由于没有保温层而在空气中的散失量。     

双螺杆挤出机

一、概述双螺杆挤出机是在单螺杆挤出机的基础上发展起来的。它是在一个双联腔的机筒里并排横放两根螺杆,故称为双螺杆挤出机,见图1。它由传动装置(包括电机、离合器、传动箱与止推轴承)、机筒、螺杆、加热器、机头连接器     

机筒沟槽和螺杆螺槽耦合作用下的熔融理论研究

对固体输送段和熔融段机筒开设螺旋沟槽的单螺杆挤出机,构建了基于反压缩比分离型螺杆和正压缩比沟槽机筒的耦合双槽熔融模型,并通过液压剖分式单螺杆挤出机实验平台对耦合双槽熔融模型进行了验证。结果表明:对于沟槽机筒单螺杆挤出机,利用熔融段沟槽固体塞和螺杆螺槽固体塞在机筒沟槽和螺杆螺槽界面处发生层间剪切产生的大量内摩擦热来实现物料的高效熔融是可行的;实验结果和理论模型相一致;螺杆转速对熔融长度影响不大,而螺杆结构参数则对其影响较大。     

试验用双螺杆挤出机的设计

<正> 1985年6月我厂试制成功了第一台小型双螺杆挤出机。双螺杆挤出机是多螺杆挤出机的一种,是在单螺杆挤出机基础上发展起来的。从结构来说,双螺杆挤出机是由机筒、螺杆、加热器,机头连接器,传动装置,加料装置和机座等部件组成。从性能来说,进料产量高,物料塑化好,转速     

数值模拟研究螺筒结构对单螺杆挤出机性能的影响

通过数值模拟研究了机筒内壁开螺槽的螺筒结构对单螺杆挤出机性能的影响。采用POLYFLOW软件模拟了硬质聚氯乙烯(PVC-R)熔体在单螺杆螺筒挤出机以及传统单螺杆挤出机中的三维等温流场及混合过程,并对二者的混合挤出性能进行了比较。结果表明:机筒内壁为螺旋沟槽结构的单螺杆螺筒挤出机,其混合性能相对于传统单螺杆挤出机有所提高。     

Fundamentals of plasticating extrusion. II. Experiments

Experiments were performed to develop quantitative information for designing plasticating extruders for low density polyethylene. Screw design variables explored included feed section length, compression section taper, and minimum channel depth. Operating variables included were screw speed, barrel temperature, and back pressure. A moving picture film illustrates temperature action and cross-channel temperature distribution for some typical experiments using a new type of extruder screw for 2.5 inch and 8 inch diameter extrusion. The information gathered was used to obtain relations between performance and screw dimensions and revealed an optimum combination of feed section length and compression taper.     

销钉机筒挤出机内流场的数值模拟

应用FLUENT软件,经过简化及边界处理,分别研究了Φ90普通挤出机和销钉机筒挤出机在不同转速、不同销钉布置、不同反向压差条件下胶料的流动行为。其研究结果可以用来指导销钉机筒挤出机的销钉布置设计及操作参数选取。     

销钉机筒冷喂料挤出机节能分析

介绍了销钉机筒冷喂料挤出机中销钉，螺钉及其新型温控装置的工作原理，论述了上述元件节能的理论依据。实验证明，该产品的性能优于普通冷喂料挤出机，可与引进的国外同类产品相媲美，三者能耗分别为０．０７４，０．１５－０．２２，０．１２ｋＷ．ｈ／ｋｇ。     

A mathematical model for predicting dynamic behavior of a plasticating extruder

A mathematical model was developed to predict the dynamic behavior of flowrate and melt temperature in a plasticating extruder caused by changes in operating variables such as screw speed, back pressure and barrel temperature. The model has application for on-line computer control of an extrusion process or for simulation purposes off-line. Experimental data for developing the model was obtained from a 2½ in. diameter plasticating extruder producing high impact polystyrene sheet.     

超大长径比双螺杆挤出机制备聚丙烯腈初生纤维

采用自主研发的超大长径比(136)双螺杆挤出机实现了PAN初生纤维的纺丝制备,研究了PAN粉料质量分数(16％、20％、24％)、双螺杆挤出机机筒温度(50、60、70 ℃)、循环挤出次数(0、1、2)对PAN初生纤维力学性能及表面形貌的影响.结果表明,PAN初生纤维的拉伸强度随质量分数、机筒温度和循环挤出次数的增加而...     

工艺条件对沥青炭纤维/ABS树脂复合材料导电性及力学性能的影响

研究了单螺杆挤出机挤出温度及螺杆转速对沥青炭纤维填充ＡＢＳ树脂复合材料导电性及力学性能的影响。结果表明,纤维经挤出后,纤维长度有不同程度的降低,长径比减小,随着挤出的升高及螺杆转速的降低,纤维长径比增大,挤出条件对复合材料电性能及力学性能的影响主要可归结为长径比对材料的影响,随着长径比增加,复合材料的导电性及拉伸强度均有增大。此外,复合材料导电性及拉伸强度随复合材料中纤维填加量的增多而增大。     

Research on the micro-extrusion characteristic of mini-screw in the screw extruding spray head

Extrusion production capacity is a chief factor of measuring how good the extruding spray head of Fused Deposition Modeling (FDM) is. The main geometrical parameters of screw and barrel (the active length of screw, the diameter of screw, the helix angle, the width of screw arris, the depth of screw channel, the clearance between screw, and barrel, etc.,) and the processing parameters such as screw speed, the pressure of nozzle are closely related to extrusion production capacity. In this article, the spray head is designed to be a special mini-screw extruding spray head and the mini-screw is different from common screw. The characteristics of the mini-screw in the research are that it is small in size, with narrow screw channel and wide screw arris structurally. Based on hydrodynamics and melt conveying theory, the micro-extrusion characteristics of mini-screw used in the screw extruding spray head of FDM were discussed in detail in this article. The relationship between extrusion production capacity and the main geometrical parameters of screw and barrel and the processing parameters is researched. Theoretical analysis was performed to find out the quantitative relationships between production capacity of extrusion and main parameters (the screw speed, main geometrical size of screw, the clearance between screw and barrel, and the pressure of nozzle, etc.,) so that the theoretical guidance on the design of spray head with mini-screw could be provided. The characteristic curves of mini-screw and nozzle are analyzed to find out the jointed work point of spray head. The main factors influencing extrusion capacity of nozzle are discussed in this article. Furthermore, the development of FDM will be promoted and the micro-extrusion theory would be more perfect by the research.     

Investigation of the poly(vinyl chloride) extrusion process using a feed throat with a feed pocket

The effectiveness of the extrusion process depends on a number of factors, the most important being barrel design, e.g., longitudinal or helical grooves; screw, feed opening, and polymer hopper designs are significant in this respect, too. The effect of these factors on the extrusion process has been thoroughly discussed in the available literature. This notwithstanding, there is little information providing insight on the effect of a feed pocket made below the feed opening, on the side of the barrel toward which the screw rotates, on the main characteristics of the extrusion process. For the experiments, five special profile inserts with different feed pocket depths were made and then mounted in the extruder barrel equipped with a 25‐mm diameter screw. The extrusion of plasticized poly(vinyl chloride) (PVC) at the screw speed ranging from 30 to 150 rpm was investigated. Presented graphically as charts, the obtained results show the dependences of extrudate temperature, extruder screw torque, polymer output, power supplied to the extruder and conveyed by the polymer, unit energy consumption and energy efficiency on the feed pocket depth, and screw speed. It has been found that the feed pocket made in the extruder barrel has little effect on the course and effectiveness of plasticized PVC extrusion and does not worsen the studied properties of the received extrudate; yet, it should be taken into account to ensure the highest polymer output and lowest energy consumption. POLYM. ENG. SCI., 54:2037–2045, 2014. © 2013 Society of Plastics Engineers     

Effect of process variables on melt temperature profiles in extrusion process using single screw plastics extruder

Abstract

Melt temperature is an important parameter in the melt processing of polymers. However, it is not possible to control melt temperature directly, only to influence it using processing parameters such as processing temperature settings. It is therefore important to know the influence of controllable process parameters on melt temperature. In this work, the relationships between controllable process parameters and melt temperature have been investigated for a 50 mm S + B single screw extruder. The extruder was equipped with a thermocouple mesh at the die inlet to determine melt temperature. It was found that melt pressure, die size, feed section barrel temperature, and compression section barrel temperature had a negligible effect on the melt temperature profiles generated, while increasing the screw speed resulted in higher melt temperatures. The metering section barrel temperature had a significant effect on melt temperature, thermal conduction effects being more important than shear heating effects. Equipment wall temperatures, downstream of the screw, produced changes in the melt temperature in the melt located within 7 mm of the wall. It was found that melt temperatures can be significantly different from those set on the equipment.     

超重力精馏过程传热传质机理研究

以波纹丝网为填料,以立式逆流超重力装置为主要设备,应用热量传递与质量传递理论,建立了超重力精馏装置内气、液温度分布的数学模型;以转子内半径29 mm、外半径63 mm、轴向高度32mm、内置直径1.6 mm、空隙率0.85、比表面积1 750 m2/m3的波纹丝网为填料的超重力装置为精馏设备,以乙醇-水为物系,在常压、室温进料、原料流量20 L/h、原料乙醇质量分数20%、转速800 r/min-1、回流比为1的操作条件下,对模型进行了检验。精馏段气相温度的实测值与模型计算值的偏差为1.41%,提馏段外半径的实测值与模型计算值的偏差为3.87%。