基于筛分再切的叶片结构调控工艺设计及应用

  目的  提升打叶复烤均质化程度、增强叶片结构控制能力。  方法  基于自行开发的多辊拨动式烟叶筛分装置和双辊多齿式烟片剪切装置，设计了一种基于筛分再切的叶片结构调控工艺。该系统通过对打后汇总片烟进行超大片筛分及剪切处理，使超大片缩减为合适尺寸的烟片，能降低大片率、提高中片率，以河南洛阳C3F等级烟叶为研究对象开展了应用探索。  结果  1）筛辊转速对超大片分选效果影响显著，筛辊转速增至50 Hz时，分选出的烟片内大片比例为93.93%，其中>41 mm的超大片比例可达68.70%；2）筛分出的烟片经剪切辊差速处理后超大片明显降低，11 mm~41 mm的合适尺寸烟片增加明显；3）经筛分再切工艺调控后，打后汇总烟片中的超大片比例降为13.48%，合适片比例增加至73.30%，大片率由55.90%降低至40.99%，中片率由32.99%升高至49.36%。  结论  基于筛分再切工艺的叶片结构调控工艺流程简单，能适应较大流量的生产线，可用于打叶复烤叶片结构调控。 

Design and application of tobacco strip structure control system based on screening and re-cutting technology

  Objective  In order to improve the uniformity degree of threshing and redrying and enhance the leaf structure control ability, a new technological system based on screening and re-cutting technology is designed during the threshing and redrying process.  Methods  This system adopts self-developed equipment including multi-roll tobacco screening device and double-roll tobacco re-cutting device. The aggregated tobacco strip after threshing and pneumatic process were screened and re-cutted through the new system to reduce the big tobacco strips into proper sized strips, thereby achieving the purpose of reducing the proportion of big tobacco strips and increasing the proportion of medium tobacco strips. The application of this system towards C3F grade tobacco leaves from Luoyang, Henan Province was investigated.  Results  The results show that: (1) The speed of screen roller had a significant effect on the separation effect of the ultra-big tobacco strips. When the speed of screen roller increased to 50Hz, the proportion of tobacco strips with size bigger than 25.4 mm in the separated strips was 93.93%, especially the proportion of tobacco strips with size bigger than 41 mm reached up to 68.70%. (2) The proportion for ultra-big tobacco strips in the separated strips was significantly reduced after the re-cutting treatment. The proportion of tobacco strips with size between 11-41 mm was increased notably while the characteristic size for tobacco strips was reduced. (3) After the application of screening and re-cutting technology, the proportion for ultra-big tobacco strips reduced to 13.48%, the proportion of proper-sized tobacco strips (11-41 mm) increased to 73.30%, the proportion of tobacco strips with size bigger than 25.4 mm decreased from 55.90% to 40.99%, and the proportion of tobacco strips with size between 12.7-25.4 mm increased from 32.99% to 49.36%. In summary, the control system for strip particle size distribution based on screening and re-cutting technology exhibits simple technological process and good adaptability for high production flow.  Conclusion  Therefore, this method provides a feasible way for the modulation of tobacco strip structure uniformity during threshing and redrying process.