绞龙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： 绞龙式和面机设计 信机 系 机械工程及自动化专业学 号： 0923223学生姓名： 徐 斌 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： 绞龙式和面机设计 信机 系 机械工程及自动化 专业学 号： 0923223 学生姓名： 徐 斌 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。单轴式和面机的特点：1、均采用齿轮减速传动结构，具有结构简单，紧凑，操作方便，不需复杂的维修，使用寿命长等优点。2、面斗采用不锈钢材料和特殊的表面处理，绝对符合卫生标准。3、运转应平稳，无异响。（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、熟练掌握和面机的工作原理与结构；2、熟悉单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、熟练掌握单轴式和面机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：1、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）。2、根据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。3、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：单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：单轴式和面机总体结构设计。2013年4月15日-2013年4月28日：部件图和零件图设计。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。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 Dough thermo-mechanical properties: influence ofsodium chloride, mixing time and equipmentA. Angioloni*, M. Dalla RosaAbstract Thermo-mechanical properties of doughs prepared from common wheat flour were investigated under different kneading conditions and with different amounts of sodium chloride. Dynamic mechanical thermal analysis showed that high-speed mixing and the addition of salt to dough slowed heat-induced reactions such as starch gelatinisation and protein coagulation. The effect of dough mixing technology was more significant than the amount of sodium chloride in modifying dough rheological characteristics. q 2004 Elsevier Ltd. All rights reserved.Keywords: Dough; Mixing; Sodium chloride; Thermo-mechanical properties; Starch gelatinization1. Introduction The first step in a baking process is mixing the dough; how the mixing is performed and the ingredients are incorporated and dispersed largely determine the final quality of the baked product (Aamodt et al., 2003; Basaran and Gocmen, 2003). The production of wheat dough is a process in which raw materials (mainly flour, water, salt and yeast) are mixed and subjected to a large range of strain situations. Dough is a complex mixture of starch, protein, fat and salt. Mixing has three important functions: (i) it blends the ingredients into a macroscopically homogeneous mass, (ii) it develops the dough into a three-dimensional viscoelastic structure with gas-retaining properties and (iii) it incorporates air which will form nuclei for gas bubbles that grow during dough fermentation (Bloksma, 1990; Collado and Leyn, 2000; Dobraszczyk and Morgenstern, 2003; Hoseney and Rogers, 1990; Naeem et al., 2002). Both mixing intensity and mixing energy must be above a minimum critical level to develop the dough properly, the level varying with flour and mixer type (Kilborn and Tipples, 1972; MacRitchie, 1986; Skeggs, 1985; Zheng et al., 2000). The time required for optimum dough development is positively correlated with the polymeric protein composition and the balance between protein polymers and monomers (Dobraszczyk and Morgenstern, 2003; MacRitchie, 1992; Millar, 2004). Rheological properties change during every stage of the dough making process; stress conditions are high when the dough is mixed in high-speed mixers, to become an elastic and coherent mass. Mixing speed and energy (work input) must be higher than a certain value to develop the gluten network and to produce a suitable breadmaking dough. On the other hand, an optimal mixing time has been related to optimum breadmaking performance which varies depending on mixer type and ingredients (Dobraszczyk and Morgenstern, 2003; Mani et al., 1992). For example, kneading doughs to reach optimum development using elongational flow in sheeting, required only 1015% of the energy generally imparted by conventional high speed shear mixers, suggesting that much higher rates of work input can be achieved due to the improved strain hardening of dough under extension (Dobraszczyk and Morgenstern, 2003; Kilborn and Tipples, 1974; Millar, 2004) Starch, the major component of wheat flour, making upabout 80% of its dry weight, influences dough rheological properties, especially upon heating in the presence of water when starch gelatinises (Li and Yeh, 2001). The gelatinization process includes a number of changes: absorption of water and swelling of the granules, change in size and shape of the granules, loss of birefringence and X-ray diffraction pattern, leaching of amylose from the granules into the solvent and the formation of a paste (Atwell et al., 1988). At reduced water contents, such as in dough, the changes resulting from gelatinisation are strongly dependent on the amount of water available (Eliasson, 1983; Seetharaman et al., 2004). The increase in viscosity due to starch gelatinisation has been suggested to modify structural properties of dough. In addition, the presence of sodium chloride is known to affect dough properties; salt toughens the protein and helps in conditioning the dough by improving its tolerance to mixing; the addition of salt produced a more stable and stiff dough (Galal et al., 1978; Shiu and Yeh, 2001). Moreover it is known that when salt is added to the dough, heat-induced reactions such as starch gelatinisation and protein coagulation, are slowed.The aim of the present work was to analyse the effects of increasing sodium chloride concentration and different kneading conditions on several dough thermo-mechanical properties, using a dynamical stress-strain controlled rheometer.2. Materials and methodsCommercial wheat flour was from Mulino Pivetti (Italy), sodium chloride, from Carlo Erba (Italy). AACC (2000) methods were used to determine moisture (44-19), ash (08-01), protein (46-10) and gluten (38-12) in the flour and its Alveograph characteristics. Dough samples with 50% moisture were prepared in accordance with Alveograph method AACC 54-30A (2000), using two different mixers and mixing times. In the first (sample A) the Alveograph mixer was used with standard conditions (250 g of flour was mixed with water for 7 min to form the dough). In the second (sample M) a prototype mixer was used where the ingredients were kneaded for only 15 s but at high-speed (1500 rpm). In this way high amounts of energy were transferred to the dough. The prototype mixer had a parallelpiped shape (12!8!12 cm) with two vertical arms operated by a 1.5 kW motor (Gamar s.r.l., VE-Italy). Sodium chloride, 04.5%, dry basis (d.b.) was added, for each different kneading condition and mixer type (Table 1). Before rheological analysis all doughs were rested for 30 min at room temperature in a plastic container. Doughtemperatures at the end of kneading were 2628 8C for sample A and w35 8C for sample M; although the use of prototype mixer rapidly Thermomechanical tests were made using a controlled stress-strain rheometer (MCR 300, Physica/Anton Paar; Messtechnik, Ostfildern, Germany), using parallel-plate geometry (25 mm plate diameter, 2 mm plate gap). The upper, serrated 25 mm plate was lowered until the thickness of sample was 2 mm and excess was trimmed off. The exposed surface was covered with a thin layer of mineral oil to prevent moisture loss during testing. The sample was rested another 15 min in the rheometer, before each measurement, allowing relaxation of stresses induced during sample loading to relax. All measurements were performed at a heating rate of 0.8 8C/min at fixed frequency of 1 Hz with the oscillation amplitude small enough to ensure linear viscoelasticity. The data are reported as means of measurements made on three samples, where each sample was obtained from a separately prepared batch of dough for each formulation and for the different mixers used. Significant differences in storage modulus (G0) at 1Hz were determined by Least Significant Difference analysis with P%0.05. All statistical analyses were performed with the Stat Soft Version 6.3. Results and discussion3.1. Flour chemical and physical propertiesThe chemical composition and rheological properties of the flour are shown in Table 2. Analysis of Alveograph data categorises the flour used as weak, and as seen by the P/L ratio, the gluten is richer in gliadins than in glutenins The resistance of a gluten dough to extension decreases and extensibility increases with an increasing gliadin to glutenin ratio (Grasberger et al., 2003; Kim et al., 1988;Uthayakumuran et al., 2000). 3.2. Thermo-mechanical properties of doughsThe same amounts of salt (0, 2.5, 3.5, 4.5% d.b.) were added to both samples (A; M) to check the effect of salt and different kneading conditions on sample behaviour during dynamic mechanical thermal analysis. This measurement simulates the physicochemical changes that take place during thermal treatment of dough. Figs. 1 and 2 show the effect of salt addition on the storage modulus (G0) during an oscillatory temperature ramp. Below 55 8C, G0, for both samples, gradually decreased as temperature increased, indicating softening of the dough. Thereafter, the storage modulus increased from 5560 to 80 8C and then slowly decreased. The abrupt increase can be attributed to the gelatinization of starch; the swelling and distortion of starch granules during gelatinization were responsible for the rapid increase of G0 not only by their action as a filler in the gluten network, but also by promoting effective cross-linking in the system (Dreese et al., 1988). The glutenin fraction of gluten has been found to be more sensitive to heat than the gliadin fraction; on heating up to 75 8C glutenin proteins unfolds and disulphide/sulphydryl interchange reactions are promoted, thus increasing the molecular size of the aggregates (Dreese et al., 1988; Peressini et al., 1999). The increase of storage modulus during heating has been reported (He and Hoseney, 1991) to be proportional to the starch content of the dough; indicating the physicochemical changes in heated dough are essentially due to changes in the starch fraction. For both samples the transition temperature range of salted dough appeared to be shifted to higher values than doughs made without salt (Figs. 1 and 2) as reported previously by Dreese et al. (1988) and Peressini et al. (1999). Moreover, a comparison of the slopes obtained from the linear regressions over the temperature range (5570 8C) where the G0 increased, showed that, in all cases, the slopes for salted dough were significantly lower than for unsalted doughs (Figs. 1(a) and 2(a) and Table 3).The effect of sodium chloride in delaying the starch gelatinization has been reported (Chiotelli et al., 2002; Galal et al., 1978; Peressini et al., 1999; Preston, 1989) and different explanations for this phenomenon proposed. When salt is added to dough, it lowers water activity and increases the energy necessary for chemical and physical reactions involving water (Kim and Cornillon, 2001; Seetharaman et al., 2004). Table 4 compares the slopes obtained from linear regressions at the different kneading conditions (in the temperature range from 55 to 70 8C) with respect to starch gelatinization. For each salt concentration it can be seen that the slopes sample M are lower that those for sample A, consequently the type of mixing seems to be relevant to the delay phenomenon. The doughs prepared using short time and high-speed mixing conditions, sample M, where high energies were transferred to the dough, were probably less hydrated and developed than sample A, therefore for starch gelatinization, for which water is indispensable, requires higher energy. The dough structure created in these kneading conditions could decrease the capability of water being effectively involved in starch granule swelling and therefore the gelatinization process is delayed.氯化钠、混合时间及设备对面团的热力学特性的影响摘要： 在不同揉捏条件和加入不同数量氯化钠条件下对麦粉的热力学性能进行了测试。强有力的热力学报告表明：高速混合及加入食盐会缓慢热诱导淀粉糊化和蛋白质凝结等反应。生面团混合工艺对面团流变特性的影响比相当数量的氯化钠更显著一些。关键字：生面团、混合、氯化钠、热力学性能、淀粉糊化1.引言在一个烘焙过程中第一步是混合面粉。混合过程如何进行、各成分如何进行合并分解很大程度上决定了烘焙产品的最终质量（阿莫特等，2003;巴萨兰与格兹曼，2003）。小麦面团的制作是将各天然原料（主要是面粉、水、食盐和酵母粉）混合并进行一系列的张紧操作。生面团是由淀粉、蛋白质、脂肪和食盐等组成的复杂混合物。混合过程有三个重要作用：1、使各组成成分混合成宏观上同质的物质；2、使面团变成内含气体的三维有粘弹性结构的物质；3、包含在面团发酵时为气泡变大提供核心的空气（布兰克，1990；克拉多及莱纳，2000；多布罗斯科克及摩根斯顿，2003；侯赛因及罗杰斯，1990；纳伊姆等，2002）。混合的强度和能量都要大于正常加工面团所需水平的最小值，这一水平是随面粉和混合器类型变化的（基尔伯恩及提普尔斯，1986；斯凯格斯，1985；曾等，2000）。生面团生长所需最佳时间绝对跟聚合的蛋白质合成物，以及蛋白质高分子材料和单体之间的平衡有关(多布罗斯科克及摩根斯顿，2003；麦克里奇，1992；米勒，2004)。在生面团形成的每一个阶段流变学性质都会发生变化。生面团在高速混合器中混合时，需要很高的条件才能形成有弹性、混合均匀的整体。搅拌速度、能源(工作输入)一定要大于形成面筋状物质和形成适合做面包的面团所需要的值。另一方面，最佳混合时间与由混合器决定的做面包时的最佳性能有关（多布罗斯科克及摩根士特恩，2003；马尼，1992）。例如，要揉捏生面团达到最适合在护墙板中伸长流动的状态仅需要常规高速混合器所提供能量的10-15%，由于改善的生面团张紧硬化法，能够获取更高比例的能力（多布罗斯科克及摩根斯顿，2003；基尔伯恩及提普拉斯，1974；米勒，2004）。 淀粉，面粉的主要成分，占其干重的80%左右，影响生面团的流变学性质，特别是淀粉糊化时在暖气设备中有水存在(李、叶，2001)。糊化过程包括一系列的变化：水分的吸收和颗粒膨胀；颗粒大小和形状的改变；双折射和x射线衍射样式的损耗；颗粒中的直系淀粉进入溶剂中；糊状物的形成（埃利亚松，1983；塞特曼等，2004）。因淀粉糊化导致的粘度增加被证实会改变生面团的结构形式。 另外，氯化钠的存在会影响生面团的特性；食盐会使蛋白质硬化并且对改善生面团混合时的忍耐力有帮助；加入食盐制造出更稳定更硬的生面团（加拉尔等，1978；苏、叶，2001）。再者，当在生面团中加入食盐时，热诱导比如淀粉糊化和蛋白质凝结会变慢。 本文的目的是分析不同浓度的氯化钠和不同程度的揉捏对生面团的几个热力学特性的影响，使用的是一种电动的应力-应变控制的流变仪。1. 原料和方法商务小麦来自穆利诺皮韦帝(意大利)，氯化钠来自卡洛苏丹（意大利）。AACC（2000）方法用来确定面粉中的水分（44-19）、灰烬（08-01）、蛋白质（46-10）和面筋（38-12）以及它的面筋拉力测定仪特性。根据面筋拉力测定仪AACC 54-30A (2000)方法，使用两种不同的混合器和两种不同的混合时间，准备好两个含50%水分的生面团样本。第一个样本（样本A），面筋拉力测定仪混合器在标准条件下使用（250g面粉用水混合7分钟形成面团），第二个样本（样本M）各原料在雏形混合器中仅混合15秒，但是在高速条件（1500转/分）进行。这样，大量的能量被转移到生面团中。雏形混合器的外形尺寸是（12812cm），有两个在1.5kw功率下工作的垂直搅拌轴（gamar公司，意大利）。为每种不同的揉捏条件和混合器类型加入0-4.5干基的氯化钠（表1）。在进行流变学分析之前，所以的面团都在室温条件下置于塑料容器中30分钟。在揉捏完之后，样品A的温度要在26-28，样品M要在35，即使雏形混合器的使用会使生面团温度迅速升高。表1实验生面团的构成生面团面粉（g）食盐（%）水A- MA- MA- MA- M250243.75241.25238.75B- 0C- 2.5D- 3.5E- 4.5F- 143.7G- 143.7H- 143.7I- 143.7A是用面筋拉力测定仪混合器得到的面团，M是用雏形混合器的到的面团。加水使生面团含水量50%热机械的测试用一个受控制的应力-应变流变仪（MCR 300，物理学/安东帕）和平行板几何（板直径25cm,间隙2mm）完成。在上面的直径25mm边缘呈锯齿状的平板只有在样本厚度大于2mm并且边缘被修剪过时才会下降。暴露的表面要覆盖一层薄薄的矿物油以防实验时水分散失。样本在流变仪中放置15分钟后读取测量结果，在放置期间允许压力减小。在升温速度为0.8/分，频率稳定在1Hz振荡幅度足够小而不致影响线性粘弹性的情况下完成测试。 以从三个样本获取的测试结果为基础的数据被记录下来，这些样本是从为每个方案和不同的混合器分别准备的生面团中获取的。Significant贮藏系数在1Hz时的显著不同点是由P0.05时最低显著性差异分析报告决定的。所有统计学的分析报告都由软件Stat Soft Version 6完成的。1. 结果与讨论 3.1面粉的化学、物理特性面粉化学成分和流变特性如表2所示。面筋拉力测定仪数据分析报告把面粉各成分列出，以P/L比率表示，麸质在醇溶蛋