全自动莲子剥壳去皮机的设计与试验

目前市场上的莲子剥壳去皮一体化机大多采用双边机结构,加工效率较高,但机器质量大、故障率高、调整维修困难。该文针对现有的莲子剥壳去皮一体机的缺陷,参考现有的莲子剥壳、去皮机的原理,设计出一种单边机结构的全自动莲子剥壳去皮机。莲子置于传送带,靠旋转的凹轮与莲壳表面间的摩擦,使莲子短径与传输方向保持一致;采用凸轮装置控制挡针和挡板的开合,使得莲子逐一通过;应用往复运动的刀片对传送带上的莲子进行环切;切壳后的莲子进入脱壳通道继续向前搓滚,使得壳仁分离;脱壳后的莲仁被冲皮装置夹持,绕自身旋转,受高压水枪冲击,使得莲子种皮完全脱去。对比试验表明,该机莲子完整加工率为91.3%,高于双边机;而未剥壳率和损伤率为1.9%和1.8%,低于双边机,单边机加工速度为96个/min,加工效率约为20 kg/h。因此,该文设计的全自动莲子机剥壳去皮性能更加稳定、可靠,调整维修更加简单,可实现莲子高效率低损耗的连续作业,并能加工各种粒度范围的莲子,能满足莲子剥壳去皮的实用需求,具有较好的应用前景。

Design and experiment on automatic husking and peeling machine for lotus seeds

Abstract: Lotus seeds usually are processed by manual and mechanical methods. The manual processing method is time-wasting because it can take about 70 percent of the total time to husk and peel seeds. The mechanical method can save time and have high efficiency of production. But, the existing husking and peeling machines for lotus seeds all adopt the bilateral machine structure, which has the shortcomings of too heavy, high failure rate and difficulty for maintenance and adjustment. In this study, an improved automatic husking and peeling machine for lotus seeds with unilateral machine structure was designed based on the existing lotus seed processing machine. On this machine, a conveyor belt was adopted to transport the lotus seeds, and a rotating concave wheel was used to frict with the lotus seed shell surface for adjusting the lotus seeds' direction to keep the short diameter of lotus seeds in a direction consistent with the movement direction of the conveyor belt. And then a spacing device was used to separate the lotus seeds, a cam device was adopted to control the opening and closing of retaining needle and the dam-board for ensuring that only one lotus seed could be hold between the retaining needle and the dam-board, so the lotus seeds could pass one by one. Then the lotus seed shell was cut in a circle by a shell cutting device using a reciprocating razor blade while the lotus seed rolled ahead on the conveyor belt. The blade beyond the depth of knife rest baseplate was adjustable so that the cutting depth of the lotus seed shell could be controlled. After cutting the shell, the lotus seed rolled ahead under the effect of the conveyor belt and then got into the husking channel, with the rubbing and rolling motions, the lotus shell and kernel were separated. After removing the husks, the lotus seed still rolled ahead into the rinsing device and was grasped by the rinsing device with rotation and water rinsing, so the lotus seed coat was finally completely removed by the water gun. In a test with 1000 lotus seeds, the designed machine with unilateral machine structure here achieved a higher completely processing rate (91.3% vs. 73.25%), higher non-peeling rate (5.0% vs. 4.5%), lower damage rate (1.8% vs. 9.2%), and lower non-husking rate (1.9% vs. 13.1%) than the husking and peeling machine with bilateral machine structure, a widely used machine produced by GuangChang Dongsheng Machinery Factory in China. Since the structures were different, the machine with unilateral machine structure here had lower processing rate (96 vs. 151 seeds per min) and processing efficiency (20 vs. 30 kg/h) than the machine with bilateral machine structure. The performance of the machine could be affected by the lotus seeds' mature conditions. The overripe or too tender lotus seeds may be processed with poor quality. However, the machine with unilateral machine structure here could process various sizes of lotus seeds (13-19 mm in short diameter of lotus seed). It could work smoothly and efficiently with little damage. In addition, it was more stable and reliable, and its maintenance was much simpler compared to machine with bilateral structure. Thus, it would have a good application prospect.