大型等厚振动弛张筛的筛分机理及设计方法研究

The vibration flip-flow screen is the important equipment in the dry-deep-screening progress for moist fine coal. The large-scale equal thickness vibration flip-flow screens used in China are completely dependent on imports. They are based on the static design theory of two degrees of freedom and have a structure of multi screen surface arranged in different angle, which lead to the problems such as low screening efficiency, large area occupation and poor stability. Therefore, the proposed project will research the screening mechanism and design method of the large-scale equal thickness vibration flip-flow screen. It mainly focus on the following topics：(1) Putting forward the stepwise screening virtual test method, and obtaining the configuration and motion condition of the screen surface to achieve equal thickness screening for the moist fine coal material; (2) Researching the 4 degree of freedom dynamics model of the double pendulum screening system with torsion pendulum, and establishing the kinematics design theory of equal thickness vibration flip-flow screen. (3) Analyzing the tructure dynamic characteristics under the interaction of vibration-material and presenting a robust design method of floating screen frame structure. (4) Proposing dynamic design method of the screen surface and presenting the topology optimization of the torsion pendulum, and establishing high performance dynamic design method of large-scale thickness vibration flip-flow screen. The research results will provide technical and equipment support for large-scale coal preparation plant in China and it will be of great significance to change the situation that China has relied on importation of large-scale equal thickness vibration flip-flow screen for a long time.

振动弛张筛是潮湿细粒煤炭干法深度筛分的重要装备。我国使用的大型等厚振动弛张筛完全依赖进口，且以多段筛面多倾角布置的结构及二自由度静态设计理论为基础，存在筛分效率低、占地空间大以及运行稳定性差的问题。本项目拟研究大型等厚振动弛张筛的筛分机理及设计方法，主要内容包括：(1)提出分步式筛分虚拟试验方法，建立湿细料群等厚筛分的挠曲筛面构型及运动条件；(2)研究扭力摆杆连接双质体筛分系统的4自由度振动模型，提出等厚振动弛张筛运动学设计理论；(3)分析激振-料群耦合作用下等厚振动弛张筛结构动态特性，提出浮动筛框结构的稳健设计方法；(4)提出等厚振动弛张筛筛面的动力学设计方法，对扭力摆杆进行结构拓扑优化，形成高性能大型等厚振动弛张筛的动力学设计方法。研究成果将为我国大型选煤厂提供技术保障与装备支撑，对改变我国大型等厚振动弛张筛长期依赖进口的局面具有重要意义。

振动弛张筛是潮湿细粒煤炭干法深度筛分的重要装备。考虑到传统振动弛张筛存在筛分效率低、占地空间大以及运行稳定性差的问题。本项目进行了以下工作（1）研究了挠曲筛面上单颗粒运动行为的数学模型，建立了挠曲筛面的粒群水分和粒度适用性评价机制。分析了不同操作条件下的筛面动力学模型，建立湿细料群等厚筛分的挠曲筛面构型及运动条件，以研制的新型单边驱动式弛张筛为例，结果表明该驰张筛张紧量在2mm时，筛面加速度为50g，有利于潮湿细粒物料的筛分（2）研究扭力摆杆连接双质体筛分系统的振动理论模型，分析了结构参数对动力学模型响应的影响，Adams对振动弛张筛的仿真结果发现：理论计算值和仿真值相对误差小于5%，验证了理论模型和虚拟样机模型的准确性。与此同时，建立了位移激励和复合激励下的筛面动力学方程（3）分析激振-料群耦合作用下等厚振动弛张筛结构动态特性，利用单因素分析法讨论了振幅、频率、倾角和振动方向角对最大冲击力的影响规律，利用响应面法建立工艺参数匹配模型，并研究了工艺参数对浮动筛框频率漂移的影响（4）提出等厚振动弛张筛筛面的动力学设计方法，对筛面结构进行了优化，提高了筛面疲劳寿命。并对扭力摆杆进行结构拓扑优化，使其质量减轻40%后仍能满足强度要求。除此之外，对振动弛张筛的关键部件进行了研究，研究成果为我国大型选煤厂提供了技术保障和装备支撑，对改变我国大型等厚振动驰张筛长期依赖进口的现状具有重要的意义。