步进电机闭环控制在挤压机速度系统中的应用

介绍了一种三相混合式步进电机与传统的步进电机系统截然不同的控制方式以及在挤压机速度控制系统中的应用.     

基于DSP2407高精度工业缝纫机驱动系统设计

针对工业缝纫机对速度控制的高精度的要求,采用了同步电机作为驱动电机,它采用DSP作为中央处理器,通过矢量控制和SVPWM算法,能够精确地控制电机的速度具有成本较低的优点。     

转矩流变仪RC90系统的技术与应用

介绍了转矩流变仪的发展、基本原理和应用。各种混合器、单螺杆挤出机、双螺杆挤出机、模具和后挤出机系统都能与RC90装配。RC90可用于对材料的熔融性能和热稳定性、颜料分散性、交联、固化和硫化性能以及挤出可加工性能等的研究。     

同向双螺杆挤出机的共混技术

本文论述了聚合物共混须用同向双螺杆挤出机的原理、特征及不同物料的共混技术。     

造粒机模板与切粒刀对聚乙烯颗粒质量的影响

通过多年来对聚乙烯造粒系统的调查研究及现场实践，确认了聚乙烯产品质量的影响因素。选择了造粒模板与切粒刀之间的最佳匹配。     

恒温油浴在电缆设备温控系统中的应用

针对线缆行业挤塑设备温控系统的特点 ,本文介绍一种简便易行且能较为精确地测量、校验挤塑设备温控系统温度偏差及参数修正的校验设备与方法。     

“Rolling” phenomenon in twin screw granulation with controlled-release excipients

The developed knowledge regarding use of twin screw granulators for continuous wet granulation has been primarily limited to immediate release formulations in the literature. The present study highlights an issue previously unreported for wet granulation with twin screw extruders when using formulations containing controlled-release (CR) excipients. Long (3–10?mm), twisted noodle-like granules can be produced in the presence of these excipients that are difficult to control and are anticipated to create complications in downstream unit operations to the granulator. Working with two different CR excipients, METHOCEL? K4M and Kollidon® SR, each blended at different ratios with a mixture of 80% α-lactose monohydrate/20% microcrystalline cellulose, these unique particles were found to be produced in the conveying elements of the extruder, arising from a rolling action at the top of the screw flights. The CR excipients adhesively strengthen the wetted mass, forming this undesired granule shape such that they persisted to the exit of the machine; the shape appeared most strongly affected by screw speed, producing particles of higher aspect ratio as speed was increased. Adjusting the concentration of these CR excipients in the formulation, the flow rate or the type of compression element used in the screws proved ineffective in controlling the problem. Rather, a re-design of the extruder screws was required to prevent generation of these extended-form granules.     

Progression of wet granulation in a twin screw extruder comparing two binder delivery methods

The two available wetting methods for twin screw granulation, namely foam delivery and liquid injection, were studied in detail by examining granule development along the screws as powder formulation and screw design were varied. Granulation profiles were determined by particle size analysis of samples along the screws collected using the “screw pullout” technique. Analysis of the particle size and porosity of produced granules revealed only minor differences between the two methods of wetting despite the larger dropsize of liquid injection compared to foam delivery. Excipients like microcrystalline cellulose or hydroxypropyl methyl cellulose with poor spreading properties, quantified by their specific penetration time and nucleation ratio, made the differences more apparent. The general similarities in granulation independent of wetting method implied that binder dispersion in an extruder was dominated by mechanical dispersion. Screw design (i.e., location of kneading block) had the dominant effect on the granulation process in this study. © 2014 American Institute of Chemical Engineers AIChE J, 61: 780–791, 2015     

The Impact of Linseed Oil Lipids on the Physical Properties of Corn Crisps and the Possibility of Obtaining Crisps Enriched with n‐3 Fatty Acids

Linseed oil, also known as flaxseed oil, is obtained from the dried, ripened seeds of the flax plant (Linum usitatissimum). The oil is obtained by pressing, sometimes followed by solvent extraction supported by a refining process. Linseed oil is an edible oil that is in demand as a nutritional supplement, as a source of α‐linolenic acid an n‐3 fatty acid. The aim of this work was to investigate: (1) the influence of the corn crisp extrusion process on the degradation of fatty acids in linseed oil (LO) and some preparations obtained from the linseed oil such as ethyl ester (EE) and free fatty acids (FFA) added to the corn in order to increase the nutritional value of the crisps, (2) influence of the oil and two fatty preparations obtained from it on the quality of corn crisps, (3) interaction of the lipid fraction with starch. The extrusion process did not degrade the fatty acids significantly. Expansion ratio obtained in the corn crisp extrusion process decreased from 620 % down to 153 %, the size of pores/thickness of the starch–protein walls forming the structure of the extruded product decreased from 10 μm down to 4 μm, the hardness of the crisps increased from 20 to 75 N, and number of lipid–starch complexes increased with rising polarity of the lipid fraction. FFA were complexed mostly by starch (about 90 %), to a lesser degree by EE (about 60 %) and to the least extent by triacylglycerols (about 10 %). The studies performed under industrial conditions using the single screw extruder for the production of corn crisps with the application of standard parameters of the extrusion process indicated that the addition of a mass of 5 % of the various lipids (triacylglycerols of linseed oil, ethyl esters and fatty acids obtained from linseed oil) to corn grits prior to the extrusion process significantly affect the quality of corn crisps.     

钢质管道三层PE防腐生产线单螺杆挤出机测温系统优化

针对某厂现有挤出机设备测温系统测量偏差较大的问题,提出了一种新的挤出机测温系统。该系统直接将热电偶的模拟信号转变为数字信号,再将数字信号传送到总控室,取消了长距离传输模拟信号的补偿导线,从而提高了挤出机测温系统的准确性和抗干扰能力。