变椭圆轨迹振动筛的动力学和筛选特性外文文献翻译、中英文翻译

XXX设计（XXX）外文资料翻译院 系 专 业 学生姓名 班级学号 外文出处Dynamics and screening characteristics of a vibrating screen with variable elliptical trace指导教师评语：指导教师签名： 年 月 日变椭圆轨迹振动筛的动力学和筛选特性何小梅，刘楚生 机械和电气工程学院，中国矿业大学科技，江苏省徐州市，中国摘要：理想的运动特征的振动筛是根据恒定床厚筛分过程的原理介绍。提出了一种新振动筛具有可变椭圆轨迹。一个精确的机械模型，根据所要求的运动的结构特征构成。应用多度的自由度振动原理，使振动筛的特点进行了分析。获得振动筛的运动轨迹为直线，圆形或椭圆形的运动学参数。动力学方程的稳定的解决方案通过计算机模拟的方式给了振动筛的运动。工艺参数，包括振幅，运动速度沿屏幕表面五项具体点和投掷指数，是通过理论计算获得。实验结果表明，新设计的振动筛的痕迹按照理想的筛选运动。筛分效率和处理能力可能因此被有效改善。关键词：变椭圆轨迹；固定床厚度的筛选过程；动力学模型；运动特性；筛选特征1、介绍：筛选操作是煤炭加工的一个重要组成部分。振动筛是一种最广泛使用的筛选工具。振动筛，如直线振动筛，圆振动筛、平动椭圆振动筛，有一个简单的平移运动。运动遵循相同的路径都在屏幕上，所以屏幕具有恒定的传输速度和抛掷指数，这导致低的筛分效率。增强的抛掷指数提高打破了激振电机的处理能力，降低了工作强度。在本文中，我们报告与变速运动的痕迹，是基于等厚筛分过程 3 - 4 的原则的一个新的振动筛的设计。该振动筛椭圆轨迹穿越不同的部位产生的运动程度与理想的运动。因此，屏幕处理能力和效率均可以提高。2、振动表面的理想运动和变椭圆轨迹振动筛的建议2.1常见的振动筛筛分特性振动筛，通常在一个固定的振动强度的工作。扔在屏幕表面移动材料，滚动或滑动运动。常见的安检人员，物料粒度分布在进料端广泛。能赋予材料粒子从振动筛是严重消耗。因此，大量的粒子成为层压只有很短的距离从进料端。材料的穿透屏幕内的第一个1 / 4至1 / 2的屏幕，从而影响筛选和降低处理能力 5 。细粒物质的减少导致比。颗粒的尺寸接近，或大于，网格增加。因此，筛选效率急剧下降。物料粒度均匀，同时成为能量从振动对材料受点损失。因此，粒子组成的物质的幅度和速度的增加。这使物料床层深度的进料端是厚而在放电结束它薄。这种运动导致沿筛面不对称的渗透，从而影响筛分效率和处理能力 6 。常用的筛选特性如图1所示2.2振动筛表面的理想运动和实施方案筛面运动的理想描述如下，根据等厚筛分原理。屏幕的进料端有一个较大的抛掷指数和较高的材料删除应用速度，使物料迅速渗透，导致迅速脱层压。早期的层压材料增加细颗粒材料通过网格的概率。屏幕上有一个适当的抛掷指数和更高的物料输送速度在它的中间部分。这有助于稳定细粒度的材料和渗透均匀地沿筛面长度。一个较低的抛掷指数和交货速度附近的放电端使物料停留在屏幕上，鼓励网更完整的渗透。目前有两种方法可用来提高筛分效率 7 - 8 。首先是从多个进料口材料添加到屏幕。这在实际使用中是个麻烦，尤其是在控制的分布不同的粒状材料。因此，在实际生产中，很少使用。第二种方法是采用新的筛选设备，1艾克，例如，一个恒定的厚度的屏幕。新的筛面运动导致材料保持不变，或增加，厚度。它达到更理想的运动。恒定厚度的屏幕的主要问题是，它包括一个面积大，结构复杂，维护困难。一种筛分效率好简单的结构仍然是必要的。我们设计了一个新的具有可变椭圆轨迹，是基于一个理想的屏幕运动中使用的原煤分级筛。振动筛的尺寸为3。6 mx7。5米，排料粒度大小0至50在和分类的粒度是6mnu椭圆振动筛结合圆形和直线振动筛的 9 - 10 的基本优点。椭圆的长轴和短轴确定物料输送的影响物质的松动，是准确的。3、变椭圆轨迹振动筛的动力学模型分析 我们做的激振力偏离重心，改变了振动筛的运动模式。多自由度振动系统在隔振弹簧的刚度矩阵不为零的情况下，简化研究忽略了小横摇的情形。运动被认为是在纵向上对称平面刚性梁的线性振动。在每个点的振动是一个三的重心和屏幕俯仰重心有关翻译。以往的研究忽略了在水平和垂直方向的弹性力对振动筛的摆动的影响 3，11 。一个准确的动态模型由三个微分方程，包括在垂直方向上的自由度耦合，横向和摆动的方向。该振动筛数学模型如图2所示。重力的中心，作为在静态平衡一个矩形的坐标系的原点，在刚体运动按照飞机上 12 。在广义坐标使用重心坐标中心的微分方程组，（x，y），和摆偏角，可以写成： 其中m是振动筛的质量，目前M相对于重力，0中心惯量；X和Y在X和y 0 角位移；X和Y在X和Y方向上的X和Y directionsand Y加速度是速度；摆角位移；一个安装角在阻尼系数F在X，Y方向；X和K支撑弹簧的刚度系数沿X和Y方向；AO的激振力的振幅，给出2 0 A=mrw，其中R是偏心的偏心块质量和令人兴奋的角频率，L1和L2距离半径；每个支撑弹簧和重力的中心之间的距离的旋转中心的偏心块和重心之间；和，P包括1和X方向之间的夹角。阻尼力很小，可以忽略不计。则式（1）可简化为式（2）：4、变椭圆轨迹振动筛的运动和筛选的效果分析 4.1分析多自由度运动参数振动理论多用来解决受迫振动13的一个稳定解，如下： 替代参数在式（3）到（2）式。允许一个稳定的解决方案被发现假设一个点的屏幕坐标为D（D，D）运动方程如下：当ES+CH+2ESCH=0时，D点的轨迹是一条直线。当E=，X=H时，D点的轨迹是圆。一般来说，（6）式表示方程的椭圆面直角坐标系。XOY坐标系以角速度逆时针旋转从而给定一个新的坐标系xoy。一个标准的椭圆公式在消除XDYD后可得公式（7）。从这我们可以知道一些点在一条线或一个圆圈屏幕上移动而移动的椭圆，只要对旋转中心的偏心块和重心的相对位置进行适当调整的，屏幕会得到变运动的椭圆。这提供了一个合理的抛掷指数和交货速度以及提高了筛分效率。4.2运动轨迹和筛分效率分析 稳定振动系统解决方案，就振动筛而言的，可以给出在振动筛上任一点的运动方程为公式（8）表示重心的痕迹近似圆形，水平和垂直方向的振幅在3.5mm和5mm之间。图3表示如重心的移动存在三个自由度。图3水平和垂直方向的相位差和摆角的振幅一样。5、结论 11）新振动筛变椭圆根据原则提出了运动轨迹常数床厚度的筛选过程。振动筛跟踪不同的不同点椭圆路径。运动规律也同意配合筛面的理想运动特性。因此，筛选能力和处理效率会增加。22）振动的理论运动学分析屏幕做是为了研究如何变不同参数会影响屏幕的意义。抽搐振动筛参数的议案线性跟踪，获得圆或椭圆。33）总振动筛运动的痕迹通过计算机模拟获得。筛选技术参数，包括振幅、速度和引发指数五个的特定点沿屏幕表面计算。这些参数是与筛分效率。结果显示模式设计的议案振动筛符合理想的筛选议案，设计能够有效提高筛分效率。44）励磁机轴中心的地位，相对振动筛的重心，是筛选高效的极为重要的。因此，我们可以设计一个振动筛具有更高的处理的能力而又不会增加功耗调整轴中心的相对位置。这是一个点，需要进一步研究。参考文献1Wen B C，Liu F Q.振动的理论与应用机器.北京：中国机械出版，19822Gu Q B, Zhang E G.复杂轨迹振动筛研究.1998(1) :42 - 463HaoF Y.煤制备手册：技术设备.北京：中国煤炭行业出版社，19934Yan F.筛分机械.北京：中国煤炭行业出版社.19955Liu C S, Zhao Y M.筛面上的非线性特性的研究.矿物处理设备，1999(1) :45 48。6Tao Y J, Luo Z F, Zhao Y M.在重力强力分离器使JO方面的煤脱硫的实验研究.中国矿业与技 术大学.2006, 16(4) :399 403。7Zhang E G.筛分，粉碎，脱水设备.北京：中国煤工业出版社，1991。8Khoury D L.煤淸洁工艺.美国：诺易斯数据公司，19819Shang N X，Na J F. 2TYA1842 圆振动筛.矿业与加工设备,1990(2): 20 24。10Ye H D.等厚圆筛分及其应用.烧结和码垛，1999, 5 (3): 30 33。11Wen B C, Liu S Y, He Q.振动机械理论和动力学设计方法.北京:中国机械出版社，200。12Wang F, Wang H.筛分机械.北京:中国机械出版社，200113Ni ZH振动力学西安:西安交通大学出版社，198914Zhu W B.复杂运动轨迹振动筛的工作原理和计算机仿真.矿业与加工设,2004(10): 34 36。15Peder M.莫根深系列种新型的筛分概念.矿物加工，1996,7(37) :311 315。16Wen B C.圆振动筛的自动同步理论.波士顿：美国机械工程协会，1987:495 500。Dynamics and screening characteristics of a vibrating screen with variable elliptical traceHE Xiao-mei,LIU Chu-sheng School of Mechanical and Electrical Engineering, China University of Mining Technology, Xuzhou, Jiangsu 221116，ChinaAbstract: the ideal motion character sties for the vibrating screen was presented，according to the principle of screening process with constant bed thickness. A new vibrating screen with variable elliptical trace was proposed. An accurate mechanical model was constructed according to the required structural motion features. Applying multi degree of-freedom vibration theory, characteristics of the vibrating screen was analyzed. Kinematics parameters of the vibrating screen which motion traces were linear, circular or elliptical were obtained. The stable solutions of the dynamic equations gave the motions of the vibrating screen by means of computer simulations. Technological parameters, including amplitude, movement velocity and throwing index, of five specific points along the screen surface were gained by theoretical calculation . The results show that the traces of the new designed vibrating screen follow the ideal screening motion . The screening efficiency and processing capacity may thus be effectively improved. Keywords: variable elliptical trace; screening process with constant bed thickncss;dynamic model;motion characteristic;screening characteristics1、IntroductionScreening operations are an important part of coal processing. The vibrating screen is one of the most extensively used screening tools. Vibrating screens, such as linear vibrating screen, circular vibrating screen or elliptical vibrating screen, have a simple translational motion. The motion follows the same path everywhere on the screen and so the screen has constant transport velocity and throwing index, which leads to low screening efficiency. Augmenting the throwing index to improve breaks the exciting motors processing capacity lowers the working.In this paper，we report on the design of a new vibrating screen with variable motion traces that is based on the principle of screening process with constant bed thickness 3 - 4. Different parts of the vibrating screen traverse different elliptical traces and the resulting motion grees well with the ideal motion . Thus the screen processing capacity and efficiency can both be improved.2、Ideal motion for a screen surface and the proposal of a vibrating screen with variable elliptical trace2. 1 Screening characteristics of common vibrating screensVibrating screens commonly work at a fixed vibration intensity . Material on the screen surface moves by throwing, rolling or sliding motions . For common screeners , material granularity is widely distributed at the feed end . The energy imparted to the material particles from the vibrating screen is severely dissipated . Consequently，a large number of particles become laminated only a short distance from the feed end . The material penetrates the screen within the first 1/4 to 1/2 of the screen , which affects screening and lowers processing capacity 5. The decrease of fine-grained material causes the ratio of. particles close in size to，or larger than，the mesh to increase . Thus，the screening efficiency declines dramatically . The material granularity simultaneously becomes uniform and the energy imparted from the vibrations to the material suffers little loss . Hence , the amplitude and velocity of the material particles increase . This causes the material bed depth at the feed end to be thick while at the discharge end it is Thin . This kind of motion leads to an asymmetrical penetration along the screen surface, which influences the screening efficiency and processing capability 6. Common screening characteristics are shown in Fig. 12. 2 Ideal motion for screen surface and implementing schemeThe ideal motion for screen surface is described below, according to the principle of screening process with constant bed thickness . The feed end of the screen has a bigger throwing index and a higher material del ivery velocity，which makes bulk material quickly penetrate and causes rapid de-laminating. Earlier lamination of material increases the probability of fine-grained material passing through the mesh . The screen has an appropriate throwing index and a little higher material delivery velocity in its middle part .This is of benefit for stabilizing fine-grained materials and for penetrating uniformly along the screen length . A lower throwing index and material delivery velocity near the discharge end causes the material to stay longer on the screen and encourages more complete penetration of the mesh. Two methods are currently used to improve screening efficiency 7 - 8. The first is to add material to the screen from multiple feed ports.This is troublesome in practical use especially in terms of controlling the distribution of differently granulated materials. Hence it is rarely used in practical production. The second way is to adopt new screening equipment 1 ike, for example, a constant thickness screen. The motion of the new screen surface causes material to maintain the same, or an increased, thickness .It achieves a rather more ideal motion.The main problem with the constant thickness screen is that it covers a bigger area and that the structure is complicated and hard to maintain . A simple structure with good screening efficiency is still a necessity. We have designed a new vibration screen with a variable elliptical trace that is based upon an ideal screen motion for use in raw coal classification.The size of the vibrating screen is 3. 6 mX7. 5 m, the feed granularity is 0 to 50 inin and the classification granularity is 6mnu Elliptically vibrating screens combine the basic advantages of both circular and linear vibrating screens 9 - 10. The long axis of the ellipse determines material delivery and the short axis influences material loosening, to be exact. 3、Dynamics model analysis of vibrating screen with variable elliptical traceWe made the exciting force deviate from the center of gravity, to change the motion pattern of the now vibrating screen. The stiffness matrix of the vibration isolation spring was not zero under these circumstances and the vibrating system had multiple degrees of freedom. Minor transverse wagging was neglected to simplify the research. The motion was considered to be a linear vibration of a rigid beam in the longitudinal ly symmetrical plane. At each point the vibration is a comhination of the translation of the center of gravity and the screen pitching about the center of gravity. Previous studies neglected the influence of elastic forces in the horizontal and vertical direction on the swing of the vibrating screen 3, 11. An accurate dynamic model consisting of three differential equations that include coupling of degrees of freedom in the vertical,horizontal and swing directions is proposed.The mathematical model of the vibrating screen is shown in Fig. 2. The center of gravity, is taken as the origin of a rectangular coordinate system at static equilibrium, in accordance with rigid motion on the plane 12. Simultaneous differential equations in generalized coordinates using center of gravity coordinates, (x, y), and the swing declination angle , may be written as where M is the mass of the vibrating screen, s the moment of inertia of M relative to the center of gravity, 0;x and y the displacements in the x and y0 directions;x and y the velocities in the x and y directionsand y the accelerations in the x and y directions; is the swing angular displacement; a the installation angle;fx, f yond father damping coefficients in the x,y and directions; x k and k the stiffness coefficients of the supporting spring along the x and y directions；AO the amplitude of the exciting force, given hy2 0 A =mrc , where r is the radius of eccentricity the mass of the eccentric block and the exciting angular frequency; L1 and L2 the distances between each supporting spring and the center of gravity s the distance between the rotating center of the eccentric block and the center of gravity; and, P the included angle between the 1 and x directions. The damping force is rather small and can be neglected. Then Eq. (1) can be simplified to Eq. (2)4、Motion and screening effect analysis of a vibrating screen with variable elliptical trace4.1 Analysis of the motion parameters Multiple degree of freedom vibration theory was used to find a stable solution for the forced vibration 13,as follows:Screen coordinates,assuming apoint to D(D,D) equations of motion are as follow： When ES+CH+2 ESCH=0, the trace of point D is a line. When E =Sand C =H，the trace of point D is a circle. In general. (6) expresses the equation of an ellipse. The xoy coordinate was rotated Y degrees anticlockwise to give a new set of x oy coordinates. A standard elliptical equation was then obtained after eliminating D D x y in Eq. (7)From this we know that some points on the screen move in a line or a circle while others move in an ellipse .As long as the relative position of the rotating center of the eccentric block and the center of gravity are properly adjusted, variable elliptical motion of the screen will be obtained . This provides a reasonable throwing index and material delivery velocity and improves screening efficiency.4. 2 Analysis of motion trace and screening efficiency.The stable solution of a vibrating system, in terms of the vibrating screen, can be given byThe equations of motion for any point on the vibrating screen areEq. (8) shows that the center of gravity traces an approximate circle and that the amplitude in the horizontal and vertical directions is between 3. 5 mm and 5 mm. Fig. 3 shows how the center of gravity moves in three degrees of freedom. Fig. 3 gives the angular phase difference between the horizontal and vertical directions as well as the amplitude of the swing angle.5、Conclusions(1)A new vibrating screen with variable elliptical motion trace was proposed according to the principle of screening process with constant bed thickness. Different points on the vibrating screen trace differentelliptical paths. The motion pattern agrees well with the ideal motion characteristic for a screening surface. Thus, screening capacity and process efficiency can be increased.(2)A theoretical kinematic analysis of the vibrating screen was done to study how varying different parameters affects the motion of the screen. Kinema tics parameters of the vibrating screen that motion traces are 1 inear, circular or el 1iptical are obtained.（3）Motion traces of total vibrating screen were gained through computer simulations. Screening technological parameters, including amplitude, velocity and throwing index, of five specific points along the screen surface were calculated. These parameters are related to screening efficiency. The results show that the motion pattern of the designed vibrating screen conforms to an ideal screening motion and that the design is able to effectively improve screening efficiency.（4）The position of the exciter axle center, relative to the center of gravity of the vibrating screen, is extreme!y important for screening efficient. Thus, we can design a vibrating screen with higher processing capacity without increasing power consumption by adjusting the relative position of the axle center. This is a point that requires further study.References1Wen13 C, Liu F Q. Theory and Application of Vibration Machines. Bei jing:China Machine Press, 1982.2GuQ B, Zhang