双轴式和面机设计开题报告

编号无锡太湖学院毕业设计（论文）相关资料题目： 双轴式和面机设计 信机 系 机械工程及自动化专业学 号： 0923210学生姓名： 孙 勇 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： 双轴式和面机设计 信机 系 机械工程及自动化 专业学 号： 0923210 学生姓名： 孙勇 指导教师： 戴宁 （职称：副教授） （职称： ）2012年11月25日 课题来源自拟课题科学依据（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）课题科学意义和面机又称调粉机，是面食加工的主要设备，它主要用于将小麦粉与水按1：0.380.45的比例，根据用户加工工艺要求（有时加食油、食堂、及其他食物和食物添加剂）混合制成面团，广泛适用于食堂、饭店及面食加工单位的面食加工。随着市场份额的发展，手工和面的产量已跟不上人们的日常需求，和面机也应运而生。和面机操作方便，自动化程度高，不仅节省了人力，还省事省力，真正的做到了化劳力为动力的要求。和面机的产生使得面粉事业得到了更一步的发展。和面机模拟手工和面的原理，使面筋网络快速形成，使得蛋白组织结构均衡，使面的的产量大大高于手工和面，且生产出来的面品，口感光滑，透明度高，弹性好。双轴和面机的特点：双轴和面机是在单轴和面机的基础上加以改进而成，其性能较单轴和面机优越。1该机有两根旋转轴，每根轴上垂直安装数个叶片，构成平行，以相同方向转动的搅拌器。2传动方式可以由主电机通过变速箱分别带动两轴做同向旋转，也可以将一根作为主动轴，通过齿轮传动实现同向转动。（2）和面机的研究状况及其发展前景随着食品行业的日益发展壮大，生产设备产能变大的要求变得日益强烈。和面机是大多数食品行业必备的生产设备，且一般处在生产流程的上游，和面机的产能，稳定性，对整个生产线来说就显得非常重要。如果单纯靠增加设备的数量，产能虽然可以上去，但是不但设备的费用回大大增加，人力成本和故障率也会增加。为了很好的解决以上问题，于是大型和面机诞生了。大型和面机自动化程度高，机器故障率低，一个人可以轻松看护两台大型和面机，其产量可以满足大中型食品企业的需求。研究内容1熟练掌握双轴式和面机的工作原理与结构；2熟悉双轴式和面机中和面过程的运动搅拌器结构设计与受力分析；3熟练掌握双轴式和面机的各参数的设计和各传动的结构的设计；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：根据课题所确定的和面机种类，用途及生产能力确定和面机的主要构件（例如桨叶，容器）机构形式和尺寸参数，运动参数及动力参数（电机功率）。根据双轴式和面机主要构件的形式，性质及运动参数，拟定整机的机械传动链和传动系统图。计算并确定各级传动的传动比，皮带转动，齿轮转动等传动构件的结构参数及尺寸，拟定机器的结构方案图。根据结构方案图，在正式图纸上拟定传动构件及执行构件的位置，然后依次进行执行构件及传动系统设计机体，操纵机构设计，密封及润滑的结构设计。研究计划及预期成果研究计划：2012年10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17日：双轴式和面机的主要参数计算与确定。2013年3月18日-2013年4月14日：双轴式和面机总体结构设计。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21日：毕业论文撰写和修改工作。 预期成果：根据提供的主要构件参数而计算出的传动构件的参数，尺寸及机体等是合理的，可以进行正常的生产组装，最终达到双轴式和面机的工作要求。特色或创新之处 造型优美，占地面积小，机器操作噪音小。故障率低，使用寿命长。双轴式和面机可以均匀的进行搅拌，使得面团得到良好的拉伸和揉捏，适于调制韧性面团。已具备的条件和尚需解决的问题1、设计方案思路已经非常明确，已经具备使用CAD制图的能力和了解和面机原理结构等知识。2、使用CAD制图能力尚需加强，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New energy-saving mechanical mixer and Overview of adaptable die design for extrusionAbstractIn the work there are described the results from the laboratory researches of the basic characteristics (performance) of one new type of energy-saving mechanical mixer, conditionally named Eleron. These characteristics (performance) are compared with respective results of the other known in the literature and successfully used in practice mixers. The mixer is designed for mixing and aerating liquid systems and it will be effective for mixing in the ferment reactors for biochemical industries, where the processes are energy absorbing. Keywords: Mixer; Air-saturation; Power-number; Heat and mass-transfer during mixing; Aeration-number1. Introduction In implementing a long-term, energy-saving program for industry 1, the department of Heat and Mass-Transfer Technics in TU-Sofia, under the guidance of the author, has conditionally created for patent an original construction of energy-saving mixer. It has a universal function for mixing liquid systems in chemical, food, wine, tobacco, and biochemical industries. We expect our mixer to take its place with dignity in fermentation technics, because of its easy manufacture, good results in air-saturation and low energy consumption. Till now it was the investigated laboratory version of Eleron-1 mixer, which is a small type, with D=(0.25/0.35)T. Universal appearance of mixer is shown in Fig. 1. It consists of a central round disk (1), which is carrying pap (2) and four wings (3). The wings are cut through in the middle (aa) and in the beginning, near the round disk (cc), and the receiving pieces are bend arch-shaped up and downward, making four blades with radius R=(0.05/0.07)D. Their length is L=0.8pR, as (considered) from line of bend. The blades on each following wing are in different order in bend direction, and because of this in working conditions there are circumstances for vortexes. This is very important when there is more than one mixer on a shaft (Figs. 1 and 2). When mounting, we observe the axial flows, created by curved blades, to meet each other (if we aim air saturation) or to pass each other, when we aim mixing without aeration. In this way we create multitude of symmetrical current lines (vortexes), which spread symmetrically vessel.2. ExperimentalFor researching characteristics (performances) of mixer Eleron-1 there are used two identical laboratory reactors with plane bottom and releasers, respectively with volumes 6.5 and 24 dm3. Reactors diameters are, respectively 190 and 300 mm, and mixers are make up with D_0.35T. As pattern substances there are used water and die thylene glycol, which under 20C have dynamical viscosity and Pa s. Reactors configuration is on Fig. 2 and the experiment tal installation, which is used, is on Fig. 3. With this installations configuration we are researching the power consumption, working with and without aeration , heat-transfer during mixing with Eleron-1, that is why reactors have heat-transfer bogies-worm-pipes (serpentines) with respective tube diameter d1 and wind up diameter dS, which are on Fig. 2. For measuring DO2 (dissolved oxygen) in liquid phase during aeration, installation also has a bottle with nitrogen, air-compressor, sensor for DO2and a writing instrument, which register on the tape the oxygen absorption (Fig. 3).Fig. 1. Scheme of mechanical mixer Eleron-1 in appearance from above.2.1. Power coefficient determination For this mixers characteristic are usedtwo reactors and two pattern substances, and the rotation frequency of mixers shaft is changing from 100 to 1200 min_1. Rotation frequency is chosen and fixed and after that is controlled with electronic cyclometer. Eu-number is determined under equation and it is read net power consumption P, for respective rotation frequency . The dependency is in Fig. 4 and is compared with the dependency of Rush ton-turbine.2.2. Aeration-number determination This exponent is defined under known methods, which is adopted for mixing technics. In our reactor with volume 6.5 dm3, with the help of air-distributed mechanism, the air is entranced with flow of qG_0.1 to1.5 V . The researching results are on Fig. 5 and are compared and heat-transfer surface (serpentine). Fig. 2. Configuration of laboratory reactors with mechanical mixerFig. 3. Scheme of experimental installations: 1, thermostat; 2, reactor; 3, pressure vessel; 4, heat-transfer surface (serpentine)2.3. Mass-transfer coefficient determination during mixing with Eleron-1 There are used two reactors with different volumes, which have air-distributed mechanisms and sensor form easuring and registering of CO2 in water. We work under 20C, and the liquid phase, before each attempt, is scavenged with nitrogen until initial oxygen concentrationC0, which is changing progressively and is writing on the tape till establishing an equilibrium (saturation concentration) .3 Traditional Mixer3.1 Different ways to classify the mixers.3.1.1 According to the number of mixing spindles .There are single-spindle mixers and double-spindle or even triple-spindle mixers.3.1.2 According to their mixing speed .There are slow-speed mixers(less than 30rev/min), high speed mixers (above 35rev/min), and variable speed mixers.3.1.3 According to their operation mode. They can be classified into batch mixers and continuous mixers.3.1.4 According to the axis position of the mixing spindle from which the mixing arms receive torque and motion .They can be classified into vertical mixers and horizontal mixers .In this chapter, he machines will be discussed in terms of this classification.Investigations show that horizontal mixers are still the dominant mixing equipment in todays modern bakery and snack industry, for they are of simple construction, simple in operation, and cheaper to run. They also have varied capacities and can be used for a wide variety of mixtures from a thin batter for cookie depositing to extremely tough dough for Chinese snack casing.3.2 HORIZONTAL MIXERSHorizontal mixers are characterized by having a horizontally located mixing spindle on which the mixing arms are fixed into the mixing bowl .Fig.2.1 is a typical front view of this kind of mixer.3.2.1 Construction A typical horizontal mixer consists of a mixing bowl，one or two mixing spindles by which the mixing arm(s) is or are driven through transmission mechanisms，and a main frame made of either cast iron or unitary construction of heavy steel plate，One or two motors are mounted below for mixing and bowl tilting functions together with a facia control and an electric interlock system to prevent access when the machine is running. There are two types of weighing systems: one is separate from the mixer; the other calculates the weight change of the complete mixer before and after the addition of an ingredient, the mixer being located on a suitable weighing scale or platform. In this case the mixer is often referred to as a weigh-mixer.3.2.2 Mixing bowlThe bowl of the horizontal mixers is of trough-like design with a curved bottom (U-shaped in cross section) and flat ends. The bowl surfaces in contact with the dough are commonly of stainless steel or stainless clad steel. This is the usual construction for the bowl ends, where the bearings are fixed to support the mixing spindles. The bowls of large modern mixers are generally double-skinnedin the form of a jacket through which chilled water or refrigerant can be circulated to prevent the dough warming up to too high a temperature as a result of mixing friction. To avoid flour and other ingredients splashing, especially at the beginning of mixing, and for safety as well as food hygiene, the bowl is always equipped with a lid which is either removable or hinged for dough discharge and cleaning. For large mixers, he lid usually has provision for assisted ingredients feed.There are two methods of dough discharging: by tilting the bowl(110。to 180。),or by mechanically sliding down the door in front of the stationary bowl to allow the dough to fall into an underlying hopper. For a ground-floor installation, the dough is often discharged into a dough tub which is usually fabricated in heavy gauge stainless steel and is supplied separately by the manufacturer. The bowl-tilting operation is generally carried out by a worm-gear mechanism in which the worm-gear is fixed on the bowl sidewall. Feeding of the bowl is carried out either manually for small mixers, or automatically through the corresponding pipes above the mixer and by means of a weighing system for large horizontal mixers. Bowls are manufactured in a wide range of volumes which allow from a few kilograms up to 1500 kg of food materials to be mixed in them. The larger the bowl size, the greater the required power of the mixing motor, so that bigger batches of dough can be mixed, resulting in a higher rated capacity for the mixer. For most large mixers, the bowl is tilted by a separate reversible motor ranging from 0.75 to 2.26Kw.3.2.3 Mixing arms Mixing speed The mixing operation is directly performed by the mixing arms, while its power is transmitted by its driving spindle (shaft or axle).That is, the speed of the mixing arm is dependent on the speed of its spindle. Horizontal mixers are designed in either a single or dual mixing speed mode. For the dual mode, its lower speed is half the rated maximum speed. As dough mixing is often carried out in two stages-blending of the ingredients, and developing the gluten-it is essential that the first stage should be accomplished at a lower speed(for example 36 rev/min) and the second stage at the rated speed (which will be 72 rev/min).Generally speaking, the machine with a mixing speed below 30rev/min is referred to as a slow-speed mixer, and that with a speed above 35rev/min as a high-speed mixer.Modern mixers commonly cover a wide range of speed variation from 20 to 145 rev/min or even up to more than 200 rev/min, which high speed allows a quick development of gluten elastic dough by means of suitable mixing arms. The slow-speed mixers are generally used in short and soft dough mixing since a much longer time would be needed for hard and bread dough。For of the mixing arms The mixing arms are designed in various configurations and cross-sections for different mixing functions such as blending, dispersing, beating, shearing, scraping, stretching, or kneading to form either a uniform mass or a dispersion or a solution, or aeration (that is, either a soft dough or hard dough, a sponge dough or batter or topping with other food material). Some mixing tools have a floral-hoop type, oval-type, or twisting-plate type and comprised only one or two loop-like arms without a centre shaft; they are referred to asshaftlessa agitators or mixing arms. The corresponding machines are referred to as shaftless mixers. In the group, there are some other types of arm such as Z-type and S-type. Their cross-section is large to ensure strength . Their relatively complex configurations are commonly cast in one piece or are welded after forging .Attention should be paid to the coaxiality of the two sides of the arm during manufacturing to avoid severe trouble in the later mixing operation.This type of mixer can be used for a wide range of dough with different consistencies, from thin batter to extremely tough dough., as the shaftless arms are especially efficient in dealing with extensible dough, since in their rotation orbit there is always a limited clearance from the bowl inner walls, which is beneficial in showing the dough to be stretched and kneaded repeatedly to form an oriented gluten network.Some other mixing tools (agitators) comprise simple shaped arms and a centre shaft. This kind of segmented construction is easy to manufacture and assemble, and its maintenance is lower than that of those described earlier. However, to deal with sticky dough, this group of agitators are at a disadvantage since the tendency of sticky dough is to adhere to the shaft, and the circular velocity at the centre shaft area is very low, resulting in a dead space and therefore improper mixing. Sometimes the centre shaft is covered by dough, layer upon layer.The term “adaptable die design” is used for the methodology in which the tooling shape is determined or modified to produce some optimal property in either product or process. The adaptable die design method, used in conjunction with an upper bound model, allows the rapid evaluation of a large number of die shapes and the discovery of the one that produces the desired outcome. In order for the adaptable die design method to be successful, it is necessary to have a realistic velocity field for the deformation process through extrusion dies of any shape and the velocity field must allow flexibility in material movement to achieve the required material flow description. A variety of criteria can be used in the adaptable die design method. For example, dies which produce minimal distortion in the product. A double optimization process is used to determine the values for the flexible variables in the velocity field and secondly to determine the die shape that best meets the given criteria. The method has been extended to the design of dies for non-axisymmetric product shapes. 2006 Elsevier B.V. All rights reserved.Keywords: Extrusion; Die design; Upper bound approach; Minimum distortion criterion1. IntroductionNew metal alloys and composites are being developed to meet demanding applications. Many of these new materials as well as traditional materials have limited workability. Extrusion is a metalworking process that can be used to deform these difficult materials into the shapes needed for specific applications. For a successful extrusion process, metalworking engineers and designers need to know how the extrusion die shape can affect the final product. The present work focuses on the design of appropriate extrusion die shapes. A methodology is presented to determine die shapes that meet specific criteria: either shapes which pro-duce product with optimal set of specified properties, such as minimum distortion in the extrudate, or shapes which produce product by an optimized process, such as minimum extrusion pressure. The term “adaptable die design” is used for the method nology in which the die shape is determined or modified to produce some optimal property in either product or process. This adaptable die design method, used in conjunction with anupper bound model, allows the rapid evaluation of a large number of die shapes and the discovery of the one that can optimize the desired outcome. There are several conditions that need to be met for the adaptable die design method to be viable. First, a generalized but realistic velocity field is needed for use in an upper bound model to mathematically describe the flow of the material during extrusion through dies of any shape. Second, a robust crite-rion needs to be established for the optimization of the die shape. The criterion must be useable within an