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反向旋转型双螺杆挤压机及传动系统的设计

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摘要

　　　本文先分析了挤压机的市场需求和生产现状，并初步探讨了挤压机生产食品的工艺可行性；提出了用双螺杆挤压机生产食品的工艺流程。在现有挤压机的基础上，并参考了国内外比较成熟的挤压机设计方法，根据各种食品的特性和生产食品的特殊工艺要求，对挤压机的关键部位进行了相应的设计。本文详细的介绍了挤压机的主要零部件传动箱、传动系统、机筒等的结构设计，并进行了相应的校核计算；对主要传动零部件如传动箱大小齿轮，带轮，从动轴，键等进行了设计和强度校核，并对轴承承载能力进行了校核计算;本文还涉及了挤压机一些辅助元件如加料系统，加热冷却装置，模头的选择要求,并进行了简单的设计。最后，本文介绍了一些关于挤压机的安装，操作，控制和维护等方面的内容。　　

关键词：传动系统；挤压混炼；反向旋转双螺杆挤压机

摘要III

AbstractIV

目录V

1 绪论1

　　1.1 挤压机技术应用及分析1

　　1.2 国内外生产现状1

1.2.1 国内发展1

1.2.2 国际上主要有以下方面1

　　1.3 挤压机生产食品的可行性分析2

　　1.4 挤压技术在口香糖加工中的应用2

1.4.1 口香糖的市场需求2

1.4.2 口香糖的加工工艺2

1.4.3 挤压机生产口香糖的可行性4

2 食品挤压机挤压设备简介6

　　2.1 双螺杆挤压机的工作原理6

2.1.1 挤压原理6

2.1.2 挤压加工系统7

　　2.2 总体结构设计7

3 双螺杆挤压机挤压设备设计8

　　3.1 传动系统的设计及计算8

3.1.1 传动系统设计8

3.1.2 电动机的选用8

3.1.3 传动比分配8

3.1.4 主要传动零部件设计计算和校核9

　　3.2 辅助零部件设计计算20

3.2.1 加料系统设计计算20

3.2.2 加热与冷却系统的设计22

3.2.3 润滑油的选用24

4 挤压加工系统的安装、操作与维护25

　　4.1挤压加工系统的安装25

4.1.1 挤压机的安装基础25

4.1.2 调整挤压机水平25

4.1.3 机筒的安装25

4.1.4 螺秆的装拆25

4.1.5 模头的安装25

　　4.2 挤压加工系统的操作25

4.2.1 挤压机的开车25

4.2.2 开车操作注意事项25

　　4.3 挤压机的维护保养25

4.3.1 螺杆的保养25

4.3.2 机筒的保养25

4.3.3 挤压机其它部分的保养26

　　4.4 设计中的几个问题26

5 总结与展望27

　　5.1 总结27

　　5.2 展望27

致谢28

参考文献29

　　1.2.2 国际上主要有以下方面

　　　⑴ 新型挤出混炼技术与设备的开发；

　⑵ 大口径管材挤出的导向平行双螺杆机出组，钢塑复合管挤出机组和大型双壁波纹管挤出成型机组的开发研究；

　　⑶ 符合挤出成型和设备的开发研究；

　　⑷ CAD/CAM/CAE技术在塑料工业中的研究；

　　⑸ 在线检测机自动控制技术应用。

可以预测，未来挤出成型技术的发展方向是：①高速、高产化；②大型化和精密化；实现挤出成型设备的大型化可以降低生产成本。③模块化和专业化；模块化生产可以缩短新产品的研发周期，争取更大的市场份额；而专业化生产对保证整期质量、降低成本、加速资金周转都非常有利。④智能化和网络化；发达国家的挤出机已普遍采用现代电子和计算机控制技术，这对保证工艺条件的稳定、提高产品的精度都极为有利。⑤高效、多功能化；塑料挤出机的高效主要体现在高产出、低能耗、低制造成本方面。

1.3 挤压机生产食品的可行性分析

本世纪30年代，挤压技术开始应用于食品加工，它具有集输送，混炼，剪切，加热，加压等多种化工单元操作于一体的高温短时加工的特点，因此在食品加工领域的应用范围越来越广泛。除了谷物及植物组织蛋白挤压食品以外，从糖果制造到酪蛋白生产，从固体脂肪到风味成分的开发，及至饲料宠物食品加工制造都用到食品挤压机。

挤压加工概括的说是将食品物料置于挤压机的高压和适当的温度的状态下，然后突然释放到常压，使胶基和各种调味料、香料达到充分渗透、混合和输出的过程。所以用蒸煮挤压法生产可以取得更好的混合效果，原料利用率高，营养损失小，生产出的食品的口感，香味的持久力都比传统的加工方法好。

总的来说，用挤压法生产是现今的发展趋势，并且，传统的加工方法很快也会被挤压法所取代。

1.4 挤压技术在口香糖加工中的应用

　　1.4.1 口香糖的市场需求

　　　口香糖是一种胶基糖（Chewing gum）,以白沙糖为主料，配以可食用的天蓝树胶和热塑性树脂等胶基制成的可咀嚼的休闲糖果。口香糖是一种目前国际上流行的低热值食品，

被人们誉为“美容糖果”。通过不断的咀嚼，可消除口臭，加快口腔内血液流动，预防口腔感染，使面部肌肉增加弹性，不易产生皱纹等效用，因此很受人们的青睐。

　　　研究显示，中国糖果市场正向品味多样化方向发展，糖果的功能的多样化也是影响商家经营运作的关键所在，糖果正在改变着只提供热量的单一功能，朝着具有营养保健作用的方向发展，口香糖也是如此，而且当前国内市场空白点还有很多，尤其是无糖领域，需求量日益扩大，利润空间广阔，由于我国人口众多，同时随着人民生活水平和生产质量日益提高，人们的消费水平也得到了极大的提高，所以口香糖的发展正朝着多功能的方向发展，目前市场出现的无糖木糖醇口香糖需求量正在不断的加大。

　　　近年来，中国的口香糖市场以每年百分之十的速度增长，目前的市场规模已超过二十亿元。在乐天进入中国之前，市场上只有口味型口香糖，但我们把功能型口香糖引入中国。事实证明随着生活水平的提高，人们对于口香糖的要求也在逐渐变化。消费者把注意力从追求口味的多样化转移到了健齿防蛀等附加功能上来，促成了口香糖由“口味型”向“功能型”的转变,这主要归功于木糖醇的功能应用。

　　　在上世纪80年代，国外的木糖醇主要用于生产无糖口香糖。上世纪90年代后，国际市场上的木糖醇需求逐年增加，人们越来越注重保健。我国的无锡利夫糖果有限公司最早将木糖醇用于口香糖中，生产“魄力”无糖口香糖。到目前为止，国内已有广东的“益达”、深圳的“华艾康”等品牌。另外，在国内近几年许多含有木糖醇的保健品，如口服液、保龄参咀嚼片、糕点、饼干也大量投放市场。由于木糖醇的防龋齿作用，在牙膏行业也有一定的市场。

　　　总之，口香糖已成为人们生活中必不可少的一种休闲食品，且我国人口多，发展空间极大，口香糖的市场需求量会不断的提高

　　1.4.2 口香糖的加工工艺

　　　口香糖主要是由口香糖胶姆基、精幼砂糖或其他添加剂、乳化剂和香料等原料加工而成，将各种原料在约120℃温度下加以混合，混合时依一定的次序，先投入已加热溶解的基质，再投入砂糖、葡萄糖、饴糖、香料等，切必须均匀的加以搅拌。混合后的原料，其水分应保持在3%以下，成型后在温度为21℃~24℃、相对湿度为45%~50%的调温室中保持6~8h，以后才可包装。

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反向旋转型双螺杆挤压机及传动系统的设计.gif

内容简介：: 无锡太湖学院信机系机械工程及自动化专业毕业设计论文任务书一、题目及专题：1、题目反向旋转型双螺杆挤压机及传动系统设计 2、专题二、课题来源及选题依据食品挤压技术具有加工范围广、生产效率高、产品质量好、加工过程无污染等特点。双螺杆挤压机由于具备输送能力强、调控性能强的优点，广泛用于加工各种食品。本课题的任务是设计一台双螺杆挤压机，其两根螺杆反向旋转，产生比较好的输送效果，适用于高粘度物料的输送混合成型过程，并对机器的传动部分进行重点设计。通过本课题的设计，有助于学生能掌握和运用专业知识，锻炼工程设计能力。三、本设计（论文或其他）应达到的要求：查阅和整理资料，包括一篇与课题相关或相近的外文资料并进行翻译；确定课题的总体设计方案，进行开题报告；进行相关参数的选择、计算和校核；对反向旋转型双螺杆挤压机进行总体设计，绘制总装图；对传动系统进行详细的计算与设计，绘制部件图和典型零件图；对整个设计过程作出总结，撰写设计说明书。四、接受任务学生：机械94 班姓名徐志强五、开始及完成日期：自2012年11月12日至2013年5月25日六、设计（论文）指导（或顾问）：指导教师签名签名签名教研室主任学科组组长研究所所长签名系主任签名2012年11月12日编号无锡太湖学院毕业设计（论文）相关资料题目：反向旋转型双螺杆挤压机及传动系统设计信机系机械工程及自动化专业学号： 0923184学生姓名：徐志强指导教师：戴宁（职称：副教授）（职称：）2013年5月25日目录一、毕业设计（论文）开题报告二、毕业设计（论文）外文资料翻译及原文三、学生“毕业论文（论文）计划、进度、检查及落实表”四、实习鉴定表无锡太湖学院毕业设计（论文）开题报告题目：反向旋转型双螺杆挤压机及传动系统的设计信机系机械工程及自动化专业学号： 0923184 学生姓名：徐志强指导教师：戴宁（职称：副教授）（职称：）2012年11月25日课题来源反向旋转型双螺杆挤压机及传动系统设计科学依据（包括课题的科学意义；国内外研究概况、水平和发展趋势；应用前景等）（1）课题科学意义双螺杆挤出机是为解决单螺杆挤出机的局限性而发展起来的。与单螺杆挤出机相比，双螺杆挤出机更容易加入带状料，分料及玻璃纤维等物料；物料在机筒内停留时间短；塑化混合效果优良，双螺杆挤出机在我国的应用非常普遍。因此对双螺杆挤出机的进一步研究对我国的经济发展有着极其重要的意义。（2）课题研究状况及其发展前景国内发展：从主机及其塑料制品区分，中国可以制造的挤出机包括单螺杆挤出机，适合于加工各种材料及各种结构的板、片、膜、丝、棒等产品；平行异向旋转双螺杆挤出机和锥形异向旋转双螺杆挤出机，适于加工温度敏感性材料，如PVC板、管、异型材等；平行同向旋转双螺杆挤出机，适于原料共混、填充、脱挥、改性、造料，增加一定装置如熔体泵，可用于直接成型；适于高填充料生产的磨盘挤出机、往复螺杆挤出机等。在我国的塑料加工中，几乎一半的塑料都是由挤出成型来完成的。在常规但螺旋挤出机组的性能方面，我国已能生产螺杆直径为12-250的多种规格，门类齐全的挤出机组长径比大多为2530。在特种挤出机的研究领域，经我国广大科技工作者的努力已经研制出排气挤出机，电磁动态塑化挤出机，串联式磨盘动态挤出机，等多种型号，目前已进入系列的研发阶段。国际上主要有以下方面：（1）新型挤出混炼技术与设备的开发；（2）大口径管材挤出的导向平行双螺杆机出组，钢塑复合管挤出机组和大型双壁波纹管挤出成型机组的开发研究；（3）符合挤出成型和设备的开发研究；（4）CAD/CAM/CAE技术在塑料工业中的研究；（5）在线检测机自动控制技术应用。可以预测，未来挤出成型技术的发展方向是：高速、高产化；大型化和精密化；实现挤出成型设备的大型化可以降低生产成本。模块化和专业化；模块化生产可以缩短新产品的研发周期，争取更大的市场份额；而专业化生产对保证整期质量、降低成本、加速资金周转都非常有利。智能化和网络化；发达国家的挤出机已普遍采用现代电子和计算机控制技术，这对保证工艺条件的稳定、提高产品的精度都极为有利。高效、多功能化；塑料挤出机的高效主要体现在高产出、低能耗、低制造成本方面。研究内容熟悉反向旋转型双螺杆挤压机的工作原理。设计反向旋转型双螺杆挤压机。掌握反向旋转型双螺杆挤压机传动箱的设计方法。绘制挤压机及传动系统总装图、部件图和零件图。拟采取的研究方法、技术路线、实验方案及可行性分析研究方法：一是沿用塑料机械的挤压理论，采用移植、修改等方法，设计出挤压机。二是以较为成熟的挤压机原型，应用相似理论，按比例放大或缩小，设计、制造出可供实用的挤压机。三是计算机辅助设计，参照上面的方法，利用计算机进行数据处理，可用AUTO-CAD来绘制部件工作图，也可以利用计算物理学建立挤压机的数学模型，调整不同工况参数，进行模拟和优化。研究计划2012年11月12日-2012年12月31日：按照任务书要求查阅论文相关参考资料，完成毕业设计开题报告书。2013年1月1日-2013年1月27日：学习并翻译一篇与毕业设计相关的英文材料。2013年1月28日-2013年3月3日：毕业实习。2013年3月4日-2013年3月31日：反向旋转型双螺杆挤压机总体结构设计。2013年4月1日-2013年4月14日：传动箱设计。2013年4月15日-2013年4月28日：零件图及三维画图设计。2013年4月29日-2013年5月20日：毕业论文撰写和修改工作。特色或创新之处反向旋转型双螺杆挤压机的传动系统结构紧凑、动力分配合理，满足工作要求。已具备的条件和尚需解决的问题设计方案思路已经非常明确，已经具备使用AUTO_CAD的能力和机械设计方面的知识。使用AUTO-CAD的能力尚需加强，结构设计能力尚需加强。指导教师意见指导教师签名：年月日教研室（学科组、研究所）意见教研室主任签名：年月日系意见主管领导签名：年月日英文原文A simplified twin screw co-rotating food extruder: design, fabrication and testingS.A.M.A.N.S. Senanayake a, B. Clarke b,* Division of Agricultural and Plantation Engineering, The Open University of Sri Lanka, Nawala, Nugegoda, Sri LankaDepartment of Postharvest Technology, School of Agriculture, Food and Environment, SilsoeCollage, Cranfield University, Silsoe, Bedfordshire MK45 4DT,UKReceived 6 July 1998; accepted 10 February 1999AbstractA simplified co-rotating twin screw food extruder was designed, fabricated and tested in England, followed by extensive testing in Sri Lanka. It was built as a model to meet the specific product and financial constraints of less developed countries and was expected to be used in those countries to widen the production capabilities of extruded foods. The machine had an estimated delivery of 10 kg/h and was made mainly with mild steel. Two types of screw were made, one with a constant pitch of 14 mm and the other with varying pitch in segments of 14, 12 and 10 mm. The machine was powered by a 2.2 kW electric motor with electronic speed control .The machine also had electrical heating with a temperature controller and a pressure sensing device. The cost of fabrication of themachine was estimated at 2000 with most of the parts built in a fairly simple workshop. A mixture of rice and dried banana was successfully extruded as a potential snack food and on the basis of maximum expansion the best results was obtained from a barrel temperature of 120C, screw speed 125 rpm, feed moisture 15% and with a die orifice size of 3 mm. When the alternative compress ion screw was tested very similar results were achieved with no significant improvement in product expansion. 1999 Elsevier Science Ltd. All rights reserved.Keywords: Twin screw extruder; Design; Low cost; Snack food; Continuous cooker; Local construction; Cereal mixturesNomenclaturea Die diameter (mm)B Channel width (mm)C Screw circumference (mm)d Screw core diameterD Outer diameter of screws (mm)H Flight depth (mm)M Moisture content (% wet basis)n Number of fight turnsN Speed angular (rev/min)p Pitch (mm)Q Delivery rate (mm3/min)S Total helical length of screws (mm)t Temperature ()T Residence time (min)a Overlap angle of screw fights (degrees)d Calender gap (mm)e Side clearance (mm)q Product density (g/mm3 )/ Helix angle (degrees)* Corresponding author. Fax: +01525-863277; e-mail: b.clarkecran-eld.ac.uk0260-8774/99/$ see front matter1999 Elsevier Science Ltd. All rights reserved.PII: S 0 2 6 0 - 8 7 7 4 ( 9 9 ) 0 0 0 4 9 71. IntroductionExtrusion cooking is finding ever increasing applications in the food process industry. Apart from providing a means of manufacturing new products, it has successfully revolution is many conventional manufacturing processes (Harlow, 1985, Frame, 1994). Today, extruders come in a wide variety of sizes, shapes and method of operation. There are three types of food extruder found in industry: hydraulic ram, roller and screw type extruders (Frame, 1994). The screw extruders are very different to the other two having special features such as continuous processing and mixing ability. Single and twin screw types are both widely used in the food process industry. Unfortunately, most of the food extruders available in the market are either so costly that less developed countries cannot afford to buy them except by some form of assistance or outside investment or else are not appropriate for the wide variety of materials that need to be processed. As a result the growth of extrusion technology of food into these countries has been hindered despite its many advantages. Fig. 2. Plan drawing of the twin screw extruder with drive system. 1-V belt pulley, 2-gear box, 3-food seal, 4-ange clamp bolt, 5-die plate, 6-die, 7-two segments of the extruder chamber, 8-extruder screw.were made so that they could be externally screwed tothe die plate.2.5. Drive systemThe machine was driven by an electric motor of 2.2kW using a twin belt drive between the motor and a gearbox shown in Fig. 2. The speed reduction in the box was2.08 while an electronic speed controller was used to control the speed continuously over the range required.Fig. 3. Front portion of barrel showing provision for heaters, temperatureand pressure sensors. 1-slots for heaters, 2-end anges, 3-side flanges to barrel, 4-hole for pressure sensor, 5-twin holes to form the barrel.2.5.1. Motor powerIn twin screw extruders the motor power is utilisedmainly to compress and shear the food dough that squeezes through various gaps in the intermeshingscrews and the gap between the screws and the barrel.When dealing with a wide range of foods under dierentprocess conditions the shear resistance can vary widelybecause of changes in the rheological behaviour whichwould prevent accurate estimate of the motor power.Owing to the unknown character therefore of the novelmaterials a motor power was selected based on that usedfor similar materials in similar sized extruders with asafety margin and from exploratory trials in the Brabenderextruder. Rossen and Miller (1973) give a rangeof specic energy consumption gures for di.erent extruderswhich ranged from 0.02 to 0.10 kWh/kg. At 10kg/h throughput this gave a maximum power requirementof 1 kW while the Brabender trials tended to indicatea power requirement of about half of this value.The 2.2 kW, 3 phase AC motor used was amply capableof supplying this power plus all other drive friction losses.2.5.2. Gear boxIn the co-rotating extruder the two screw shafts are driven at the same speed in the same direction. The main problem is that they are very close together. The gearbox was designed to drive two pinions, coupled to the shafts by shear pins, by using a gear wheel of more than double the width of the pinions. In this way the two pinions could t side by side driven simultaneously and maximise their diameter space as shown in Fig. 2. Lubricated phosphor bronze thrust bearings were used to resist the axial load generated by the material along the shaft.2.6. Heating and temperature controlHeating of the barrel to give necessary thermal input for cooking the food was done by two sets of cartridge heaters having capacities of 800 and 1200 W. The heaters were positioned in the grooves made on the top and bottom of the barrel towards the die end as shown in Fig. 3. A single temperature controller was set up together with a thermocouple to sense the temperature inside the barrel very close to die plate. Owing to the shortness of the barrel only one thermocouple was considered necessary. In an early design heaters were also used near to the feed hopper but were not used as they tended to cause premature gelatinization of the starch and blockage of the feed.2.7. Pressure sensorPressure measurements are not so important in the commercial production processes as it cannot be directly controlled to monitor the product characteristics. Neither was such a device needed as a safety measure as this was covered by an overload cut out on the electrical supply. However, in experimental work the measurement of pressure is useful to ascertain the relationship between the pressure and the other controllable parameters such as die size, temperature, moisture content and speed. In this study, a device was built using strain gauges mounted on a small cantilever beam in order to measure the pressure inside the extruder barrel (Fig. 4). A four arm strain gauge bridge was fixed at the point of maximum bending moment. The pressure was tapped from a small hole made in the die end of the barrel in which a plunger, sealed by an O-ring, actuated the cantilever beam to transmit the pressure force. The strain in the beam was detected as a voltage difference. This feature could have been used as an automatic safety cut-out but reliance was placed instead on belt slip in the initial drive stage and the motor itself had an overheating cut-out.Fig. 4. Position of pressure and temperature sensors on the extruder barrel. 1-location of strain gauges on the pressure sensor, 2-cantilever support to plunger, 3-temperature sensor.3. Testing and evaluationA range of rice and banana mixtures were selected as being both novel yet having high potential as processed foods in Sri Lanka. These materials are cheap and common crops in most developing countries and represent an opportunity to produce an attractive, nutritious and tasty snack food. This would provide labour, utilisation of excess perishable fruits in season and a means of storing them for at least one year in appropriate packages. The main product qualities were assessed as part of the same programme and shown to be satisfactory by Gamlath (1995). The rice was prepared in the form of grits (800 lm) and the banana was dried and milled to a similar sized powder which was mixed and flood fed from the feed hopper. Extrusion trials were carried out as given below. Sixteen combinations ofvariable levels were studied in two sets of experiments. In both sets the throughput was measured when the flow became stable.Initial trials indicated no significant difference in performance due to the variable pitch screws as a means of compressing the feed so all subsequent trials and the results quoted in this paper are for the fixed pitch screws. The extrudate diameter was measured using a vernier calliper immediately after extrusion and before any further drying took place which could cause some further reduction in ratio but not to a.ect the general result. All tests were replicated three times making 48 individual trials carried out in a fully randomised formatExperiment 1Fixed settings:Speed (N) 125 rev/minDie size (a) 5 mm diameterVariables:Barrel temperature (t) two levels (100C and 120C)Feed moisture content (M) four levels (15%, 20%,25%, 30%)Experiment 2. This experiment was carried out using fixed settings of barrel temperature and the feed moisture determined in experiment 1 on the basis that maximum product expansion represented the best quality.Fixed settings:Barrel temperature (t).120CFeed moisture content (M).15%3. Testing and evaluationA range of rice and banana mixtures were selected as being both novel yet having high potential as processed foods in Sri Lanka. These materials are cheap and common crops in most developing countries and represent an opportunity to produce an attractive, nutritious and tasty snack food. This would provide labour, utilisation of excess perishable fruits in season and a means of storing them for at least one year in appropriate packages. The main product qualities were assessed as part of the same programme and shown to be satisfactory by Gamlath (1995). The rice was prepared in the form of grits (800 lm) and the banana was dried and milled to a similar sized powder which was mixed and flood fed from the feed hopper. Extrusion trials were carried out as given below. Sixteen combinations ofvariable levels were studied in two sets of experiments. In both sets the throughput was measured when the flow became stable.Initial trials indicated no significant difference in performance due to the variable pitch screws as a means of compressing the feed so all subsequent trials and the results quoted in this paper are for the fixed pitch screws. The extrudate diameter was measured using a vernier calliper immediately after extrusion and before any further drying took place which could cause some further reduction in ratio but not to a.ect the general result. All tests were replicated three times making 48 individual trials carried out in a fully randomised formatExperiment 1Fixed settings:Speed (N) 125 rev/minDie size (a) 5 mm diameterVariables:Barrel temperature (t) two levels (100C and 120C)Feed moisture content (M) four levels (15%, 20%,25%, 30%)Experiment 2. This experiment was carried out using fixed settings of barrel temperature and the feed moisture determined in experiment 1 on the basis that maximum product expansion represented the best quality.Fixed settings:Barrel temperature (t).120CFeed moisture content (M).15%Table 1Results of Experiment 1 (Die orifice diameter=5 mm, screw speed=125 rpm)Temperature (C) Feed moisture (%) Throughput (g/s) Expansion ratio Pressure (MN/m2)100 15 3.76 1.01 2.97100 20 2.56 1.00 2.38100 25 2.04 1.00 1.83100 30 1.25 1.00 1.38120 15 2.16 1.06 2.91120 20 2.00 1.05 2.07120 25 1.18 1.01 1.59120 30 1.02 1.00 1.38Variables:Die orifice diameter (a) two levels (3, 4 mm)Speed (N) four levels (100, 125, 150, 175 rev/min)4. Results and discussion4.1. Machine performanceGenerally the extruder performed very satisfactorily.The extrudates produced by the machine were fairly well expanded. During extrusion operations it did not become necessary to dismantle the barrel lengthways by splitting into two halves as it never seized up. In order to clean the screw and barrel the latter barrel was very easily pulled o. from the screws within a few minutes after extrusion. This was in part due to a shorter than usual barrel length. This suggests that the horizontal splitting of the barrel was not essential which would make the machining process of the barrel far easier. No serious difficulties were encountered as far as the operation of the machine is concerned, except initial feedingproblems due to a temperature rise close to the feed hopper. This happened because some heaters were installed a little too close to the feed point so these were later removed and the difficulties were overcome as mentioned earlier. Many extruders have cooling facilities in this region but these were not found to be necessary. Those heaters further from the feed point and close to the die end proved to be sufficient to gelatinize the rice grits. The extrudate was observed to change from a powder at feed to a continuous, expanded extrudate at exit although quantitative assessments of the degree of gelatinization were not carried out.4.2. Extruder settings and product characteristicsIt can be seen from Table 1 and Fig. 5 that the throughput dropped with each increase of feed moisture content at both the barrel temperatures used. When the feed moisture was increased from 15% to 30%, the throughput was reduced by 66.8% and 52.7% at 100 and 120barrel temperatures, respectively. This effect was probably caused by an increase in backflow allowed by the reduced viscosity which the increase in moisture produced. Another important observation made was the variation of product expansion with the pressure and feed moisture content. The expansion was found to be highest at the lowest moisture content with associated highest pressures (Fig. 6) and a steady reduction in both expansion ratio and pressure as moisture content increased. The product was well gelatinised but with low expansion ratio. The second series was designed to test a wider range of parameters and if possible increase the expansion ratio which was thought to depend on the die diameter.The results of Experiments 2 are tabulated in Table 2 below.Fig. 5. Throughput as a function of feed moisture content with die diameter 5 mm and screw speed 125 rev/min.Fig. 6. Pressure and expansion ratio as a function of feed moisture content at feed moisture 15%, die diameter 5 mm and screw speed 125 rev/minFig. 7 and Table 2 show that the throughput increased with the speed due to increased rate of material conveyance. The pressure changes with screw speed was not found to be significant. The product expansion, however, showed a downward trend with the increase of speed as evident from Fig. 8. This reduction can be attributed to the reduction of pressure and lower degree of gelatinization due to reduced residence time. At settings of 125 rpm, feed moisture 15%, temperatures 120C, die size 3 or 4 mm diameter a very acceptable product was achieved.The overall performance of the machine was found to be quite satisfactory in achieving all the parameter settings and measurements required. Each trial only lasted a few minutes in running time which was mainly spent in reaching equilibrium conditions indicated by the temperature reading but after 48 trials no significant wear was observed even though the prototype was in mild steel.Cleaning and maintenance was quick and simple and in the event of a complete seizure of the screws the barrel could be split on this machine.The gearbox was of a bolted construction to permit modifications but future designs should be welded together. The 2.2 kW motor was found to be amply capable and most of the time it only consumed about 0.5kW. No mechanical breakdowns were experienced.The prospects for use of this design in developing countries seem to be good from these experiments. Scale up to a higher capacity would bring some difficulties as discussed by Levine (1989); Singh, Smith and Frame (1998) and Yacu (1992) and although these issues were not addressed they are not considered to be insurmountable.Fig. 7. Throughput as a function of speed with feed moisture 15% and barrel temperature 120C.Fig. 8. Pressure and expansion ratio as a function of speed with 3 mm die size, feed moisture 15% and barrel temperature 120C.5. ConclusionsThe following conclusions were made from this study. Simplified extruders for specialised applications can successfully be made and operated in less developed countries to process local food materials. All components can be made in an unsophisticated workshop except gears, seals, motor, temperaturesensor and heaters. Simple machining processes such as drilling and boring can be used to produce twin holed barrels to accommodate the intermeshing screws. Horizontal splitting of the barrel is not essential in this type ofmachine so that fabrication of the barrel for these machines can be simple enough for developing country manufacture. A simple construction of gear box, using straight spur gears driven by a single large gear wheel is quite adequate to run the twin screws in the same direction. An attractive and acceptable snack food was produced from the prototype machine from mixture of cereals and fruits.6. ReferencesFrame, N. D. (1994). The technology of extrusion cooking. Blackie Academic and Professional, London.Gamlath, G. G. S. G. (1995). Nutritional, Physico-chemical and sensory evaluation of extruded cereals with perishables. Ph.D. thesis, Cranfield University, Bedford, England.Harlow, N. (1985). Revolutionising a cereal need. Food Processing, pp. 29-30.Harper, J. M., & Jansen, G. R. (1985). Production of nutritious precooked foods in developing countries by low cost extrusionTechnology. Food Review International, 1, 27 97.Harper, J. M. (1979). Food extrusion: critical reviews in food science and nutrition. Florida: CRC press.Harper, J. M. (1992). A comparative analysis of single and twin screw extruders. In J. L. Kokini, C.-T. Ho & M. V. Karwe, Foodextrusion science and technology. New York: Marcel Dekker.Hauck, B. W. (1985). Comparison of single and twin screw extruders- 2. Food Trade Review (Suppl. 59).Hauck, B. W., & Ben Gera (1987). Single and twin screw extruders. Milling, pp. 1820.Jansen, G. R., & Harper, J. M. (1980). Applications of Low cost extrusion cooking to weaning foods in feeding programs. FAOFood and Nutrition, 6(1), 2 9; (1) 15 23.Jansen, L. P. B. (1978). Twin screw extrusion. Amsterdam: Elsevier.Levine, L. (1989). Scale-up, experimentation and data evaluation. In C. Mercier, P. Linko & J. M. Harper, Extrusion cooking (pp. 57-90). USA, DC: American Association of Cereal Chemists.Martelli, F. G. (1983). Twin screw extruders- A basic understanding. New York: Van Nostrand Reinhold.Rossen, J. L., & Miller, R. C. (1973). Food extrusion. Food Technology (Chicago), 27(8), 4653.Ryder, G. H. (1953). Strength of materials (pp. 259261). LondonW8: Cleaver-Hume Press.Seiler, K. (1984). Extrusion cooking and Food processing. Food Trade Review, 124/127.Sahagun, J. (1977). Parameters a.ecting the performance of a low cost extrusion cooker. M.S. Thesis, Department of Agricultural and Chemical Engineering, Colorado State University, Fort Collins,USA.Singh, N., Smith, A. C., & Frame, N. D. (1998). E.ect of process variables and monoglycerides on extrusion of maize grits using two sizes of extruder. J. Food Engrg., 35(1), 91109.Smith, A. (1986). Cooker extruder die design-some fundamentals.Food Trade Review, 56, August 1986, Impulse Food Suppl. (612).Yacu, W. A. (1992). Scale-up of food extruders. In J. L. Kokini, C. Ho & M. V. Karwe, Food Extrusion Science and Technology (pp. 465 -472). New York: Marcel Dekker.Van Zuilichem, D. J., Stolp, W., & Janssen, L. P. B. M. (1984). Engineering aspects of single and twin screw extrusion cooking of bio-polymers. In R. Jowett, Extrusion Cooking Technology. Amsterdam: Elsevier.中文译文一个简化双螺杆旋转食品挤压机：设计，制造和检验S.A.M.A.N.S.Senanayake,B.Clarke农业的和耕地工程学的分割。斯里兰卡的开放型大学，纳瓦拉，斯里兰卡技术部，农业、食物和环境的学校，悉尔索农业大学，克兰菲尔德大学，悉索尔，贝德福德郡，MK45 4DT,UK收到1998年7月6日;接受1999年2月10日摘要一个简化双螺杆旋转食品挤压机的设计，制造和测试在英国，之后在斯里兰卡广泛的测试应用。它是作为一个模式来满足特定的产品和金融限制，较不发达国家，预计将在这些国家扩大生产能力，膨化食品。机器有一个 10 公斤小时的估计输出而且主要是碳钢所做。螺旋的两类型被做了，一个有固定摊位的14毫米和其他不同的音高段14, 12和10 mm。这个机器是采用变频电机与电子速度控制。该机也有电加热温度控制器和一个压力感应装置。制造成本的估计2000欧元，大多数部分建立在一个相当简单的工作坊。一个米的混合物和干燥的香蕉成功地当做潜在的点心食物和根据最大展延被挤出，最好的结果从一个 120 的滚筒式打印机温度被获得，螺旋加速 125个转/每分，输送水分 15%而且与一钢模囗 3 毫米的尺寸相当。当其它可能的压缩螺旋被测试非常相似的结果与没有产品展延中的重要的改良一起达成。1999全文电子期刊公司。版权所有。关键词：双螺杆挤出机，设计低成本，休闲食品，连续蒸煮器，地方建设，谷类混合物1.驱动系统这台机器是由电机和齿轮箱之间使用双皮带传动的电动机（220KW）驱动的（图2）。箱子减速器是用电子调控器来达到持续变化范围内的速度的要求的。图2用传动系统的对螺旋挤压机的平面图制图。单一三角皮带滑车 2-齿轮箱、 3 食物的封囗，4-凸缘夹子螺栓， 5 一钢模的屏，6-一钢模，挤压机室的 7- 两个片段，8-挤压机转。（1）电机功率在双螺杆挤出机电机功率的利用主要压缩和剪切食物生面团挤压，通过各种差距在啮合螺丝和螺丝之间的差距和桶。当处理一个范围广泛的食品不同工艺条件下的剪切阻力可能差异很大，因为变化的流变行为，防止准确的电机功率。由于未知的变化和新奇材料等，一个马达的能力被选择了基于一个安全界限和从布拉班德挤压机的探索试验在相似的按规定尺寸制作挤压机中为相似的材料。罗森和铣床为从 0.02 到 0.10KWh/kg 的不同的挤压机提供多种比能量消费数据。在10kw吞吐量时，这给一个1kw的最大动力要求而布拉班德审讯倾向于表明一个相关的电源要求这个的一半值。2.2 KW，被用的 3 相位交流电动机加上所有其他磁盘摩擦损失等供给充足有能力。（2）齿轮箱在同向旋转挤压机中，螺旋桥以相同的方向和相同的速度被驱使。主要的问题是他们在一起非常接近。齿轮箱被设计成驾驶两个小齿轮，藉着剪梢对桥加倍了，藉由使用齿轮比倍更多小齿轮的宽度。这样，这两个小齿轮会并排安装并且同时地驱使，如图 2 所显示的他们的直径空间增加至最大限度.被加油的磷青铜推力方位被用来抵抗沿着事物产生的桥方向的负载。2.加热与温度控制滚筒式打印机的加热给煮熟食物的必需的热输入分两组卷筒加热器有800W 和1200W的容量。加热器在槽向如 Fig.3 所显示的一钢模结束在滚筒式打印机的顶和底上被做中放置。一个温度控制器连同一个热偶一起被建立在滚筒式打印机内温度接近的死屏。由于滚筒式打印机的脆性所以只有一个热偶被视为必需的了。在一个早期设计暖气并且使用靠近进料斗现在不使用是由于他们倾向于原因为时过早糊化的淀粉和阻止费。图3: 加热器、温度和压力感应器的滚筒成绩准备的前面部分。1-为加热器起槽，2-结束凸缘，3-边凸缘快速前进，4-为压力感应器挖洞，5-双排电洞造形滚筒式打印机。3.压力传感器压力尺寸不是那样重要。在广告生产过程由于这不可能直接控制对显示器的产品特点。当这在电的供给上的外被超载了复盖且剪下的时候 , 一个不可或缺的装置即一个安全测量也是。然而，在实验的工作中，压力的测量有用确定压力和其他可控制的叁数，像钢模尺寸、温度之间的关系，水分足而且满足加速。在这研究中，一个装置被建造了并且使用在一个小展开的应变计的悬臂梁上为了是要在挤压机滚筒式打印机内有压力（图4）。四个臂应变计桥接器被濒于最大弯曲（力）矩定盘了。压力从一个小电洞，在一个被一个 O 环封闭的活柱，促使了悬臂梁传送压力的滚筒式打印机的钢模被挖被轻打。波束的应变当做一个电压差额被发现。这特征可能有作为一个自动安全断路器并且被信赖放置代替在皮带打滑在初步驱动器阶段且马达本身有一个过热开孔。图4：压力和在挤压机滚筒式打印机上的温度感应器的职务。在压力感应器上的应变计的 1-位置，2-悬臂对活柱，3 温度的感应器支援。4.测试与评估多种米和香蕉混合物被选择了当做仍然有高电位为斯里兰卡的加工食品。这些材料在大多数发展中国家中是廉宜、通常的农作物和一个机会容易生产吸引人、有营养成份而且好吃的点心食物。这将给劳工过剩的利用易腐烂的水果，储存的一种方法减少他们为至少一年的适当包装。主要的产品性质被估定为相同的程序表的一部份而且显示由 Gamlath 变得满意了（1995) 。米以砂砾（800um) 的形式被准备这，而香蕉被弄干而且磨工到一个被混合的相似的按规定尺寸制作粉末了和从输送漏斗被喂的泛光性。挤出试验被实行如给定的变化。易变层次的十六个结合在两组实验中被研究。在两组实验中，当流量变成持稳时，传输量被测量了。初步的审讯表明无重要区别在于可变螺距螺旋由于压缩的一个手段以及所有连串的审讯，结果引用在这篇论文中为固定摊位螺旋。出胶直径被测量了，立刻使用幼频调节器，卡钳在挤出之后而且在任何较进一步的干燥发生时哪一个会在比率中引起一些较进一步的缩减之前但是不影响一般的结果。所有检验在那里被复制时作以一个完全随机化的格式被实行的了48个个别的试验。实验1 被定盘的设定：速度：125 r/min 钢片尺寸：5 mm diameter 变量：料筒温度：100和120 喂水分含量：15，20，25，30 实验2. 这实验被进行使用固定环境的料筒温度，费水汽确定在实验1依据如此最大产品扩张代表最好的质量。被定盘的设定：料筒温度=120 喂水分含量=15实验结果1（一钢模囗直径=5mm，螺杆转速=125rpm）温度（）输送水分（）传输量（g/s）展延比率压力（MN/m ）变量：一钢模囗直径（a）两个闸柄（3,4 毫米）速度（N）四个闸柄（100,125,150,175转分）4结果与讨论（1）机器性能通常挤压机能够非常满意地执行操作。被机器生产的压出胶很好地并且公平地被扩大了。在挤出操作期间，它没有变成必需的，从不进入二等份之内并当做它藉由分离长拆除滚筒式打印机并且抓住在上面。为了要清理螺旋并且要快速前进较后者的滚筒式打印机非常容易地在挤出之后在几分钟之内从螺旋顺利完成。这部份地是要看一个比平常短的滚筒式打印机长度了。建议水平滚筒式打印机的分离没有必要哪一个会让滚筒式打印机的机制程序远疲劳。就机器的运算来说不会遇到严重的困难，除了初次的逐渐强烈的问题以外有输送漏斗附近的一个温升。因为一些加热器被安装了，所以这发生了有点儿接近输送点并且这些稍后被移动了，而且困难依照早早地提到并被克服。许多挤压机有这一个区域的冷却的设施，但是这些没被发现是必需用的。那些加热器更进一步地从输送点和接近地对证实充份成胶状米砂砾的一钢模结束。挤出物被观察使从一个粉变成在向一个提供食物连续，扩大挤出物在出口尽管程度的评估的糊化而不是进行。（2）挤压机设定和产品特性它能被从表 1 和图5 传输量在被用的这两个滚筒式打印机温度以输送水分含量的每个而增大下滑。当输送水分被增加 66.8 和 52.7在 100和 120快速前进温度时，并分别地。这效果大概造成了一个在回流方面增长允许由比浓粘度在湿度方面增长生产。被做的另外的一个重要的观测用压力是产品展延的变化和喂水分含量。扩张被发觉是最高在最低湿度使满足于关联最高的压力(fig。6)，一个稳定减少在两者都扩张无线电和压力的情况下，由于含水率提高，产品除了被低的展延无线电所成胶状之外，第二系列被设计测试一个广泛类型的叁数了而且合理的增加被认为取决于一钢模直径的展延比率。图5：传输量当做一个输送水分含量的职能以一钢模直径 5个毫米和螺旋加速 125转/分图6：压力和展延比率当做职能在输送水分 15% 的输送水分含量,一钢模直径 5个毫米和螺旋加速 125转/分实验的结果2被制在表2下面。图7 和表 2 表示传输量由于物质运输工具的率增加而以速度增加。压力变化用螺旋速度没被发现而变得更加重要。然而，产品展延从 Fig.8 用速度的增大表示一个下滑的倾向来看是显然的了。这个减少能归因于压力降低，降低糊化的学位在于减少停留时间。在 125转/每分的设定时，喂水分 15,温度 120,一钢模尺寸3 或4 毫米直径一个最合格产品被达成了。图7：吞吐量根据快同湿度15%，料筒温度:120实验结果2：（输送水分=15%,料筒温度=120）一钢模囗直径（mm）螺杆转速（rpm）输入量（g/s）展延比率压力（MN/m ）图8：以 3 毫米一钢模尺寸当做一个速度的职能压力和展延比率，喂水分 15% 而且快速前进温度 120机器的总性能被发现变得相当满意了，在达成所有的叁数设定和测量方面时是必需的。每个试验主要地在达成被温度指示的平衡条件方面被花费的正在运行中的时间只持续数分钟阅读但是在 48个试验没有重要的磨耗之后即使原型在软钢中被观察了。清洗和维护是快而且简单的和万一一个完整发作的螺旋桶可以是在这个上产生分歧机器。齿轮箱一个被闩住的构造准许修改，但是将来的设计应该一起被焊接。2.2 KW的电动机被发现是它只消耗大约 0.5个千瓦的充足有能力、大部份的时间了。没有机械的故障是有经验的。在发展中国家的这设计的在使用展望似乎从这些实验看来很好。标度提高到一个较高的容量会带来如 Levine 所讨论的一些困难（1

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