高筱钧, 周金华, 赖庆辉. 中草药三七气吸滚筒式精密排种器的设计与试验[J]. 农业工程学报, 2016, 32(2): 20-28. DOI: 10.11975/j.issn.1002-6819.2016.02.004
    引用本文: 高筱钧, 周金华, 赖庆辉. 中草药三七气吸滚筒式精密排种器的设计与试验[J]. 农业工程学报, 2016, 32(2): 20-28. DOI: 10.11975/j.issn.1002-6819.2016.02.004
    Gao Xiaojun, Zhou Jinhua, Lai Qinghui. Design and experiment of pneumatic cylinder precision seed-metering device for panax notoginseng[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2016, 32(2): 20-28. DOI: 10.11975/j.issn.1002-6819.2016.02.004
    Citation: Gao Xiaojun, Zhou Jinhua, Lai Qinghui. Design and experiment of pneumatic cylinder precision seed-metering device for panax notoginseng[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2016, 32(2): 20-28. DOI: 10.11975/j.issn.1002-6819.2016.02.004

    中草药三七气吸滚筒式精密排种器的设计与试验

    Design and experiment of pneumatic cylinder precision seed-metering device for panax notoginseng

    • 摘要: 因中草药三七种植属于密集型精密种植模式,尚无满足种植要求的播种机,为解决三七机械化精密播种问题,研究设计了一种气吸滚筒式精密排种器。该文阐述了三七气吸滚筒式精密排种器的工作原理,确定了其主要结构参数,构建了充种和投种过程种力学模型。以云南文山三七种子为播种对象,采用二次旋转正交组合试验方法,对排种器进行了排种性能试验研究,并通过投种对比试验验证了零速投种的必要性。建立了负压、前进速度、吸种角度3个主要因素与合格率、漏播率、重播率的数学模型,分析了各个因素及交互作用对合格率的影响规律,并进行了参数优化与验证试验。影响排种合格率的因素主次顺序为负压、前进速度和吸种角度;确定最佳参数组合为吸种角度为20°,负压值660~720 Pa,前进速度在0.72~0.76 m/s,可获得合格率大于90.2%,漏播率小于4.9%,重播率小于5.3%。经试验验证,试验结果与优化结果基本一致,满足三七精密播种的种植要求。试验结果表明此种气吸滚筒式精密排种器对于三七种子具有很好的播种适应性。该研究为应用于田间阴棚内播种的气吸滚筒式精密排种器的设计提供了参考。

       

      Abstract: Abstract: Notoginseng is one of rare medicinal herbs in China, and it is mainly grown in Yunnan Province. Market demand of notoginseng is very large, and hence, until December 2014, the planting area of notoginseng has reached 40000 hm2. At present, the main planting pattern is through manual operation, and the labor intensity is very high and the sowing quality is discrepant. However, there is no precision seeding device suitable for notoginseng. Therefore, the mechanization planting of notoginseng has important practical significance. Notoginseng is planted on small plots of land, the planting density and the requirement of seeding precision are high, so we designed a small sized precision metering device. The liquidity of the seeds is not good and the shape of seeds is irregular for notoginseng, so we chose the pneumatic seed-metering device to adapt to the characteristics of the seeds accordingly. In order to meet the precision seeding requirements of notoginseng planting, a unique pneumatic cylinder-type precision metering device was designed. This device integrated the features of vacuum suction, insulated pressure for seed-clearing and zero speed of seed dropping. In this paper, the main structure and the working principle of the metering device were expounded. The pitch-row of the hollow shaft was determined and the stability of the flow field was ensured by the flow field analysis through the computational fluid dynamics (CFD) software. The key structure parameters were determined through theoretical calculation according to planting requirements. The contrast test of dropping seed indicated that zero speed of seed dropping was necessity. According to the extensive testing combined with the experimental results of relevant scholars, the main factors which affected seeding performance of pneumatic cylinder precision seed-metering device were determined, which were forward velocity, negative pressure and adsorption angle. During the test process, in order to reach zero speed of seed dropping, the installation angle of adjustable insulated pressure plate was changed with forward velocity. The notoginseng seeds in Wenshan were chosen for sowing object. Based on the three-factor five-level quadratic orthogonal rotating combination test method, the influences of forward velocity, negative pressure and adsorption angle on sowing performance were explored. The experimental results showed that the influence of negative pressure on the qualified rate was very significant (P<0.01), and the influences of forward velocity and adsorption angle were significant (P<0.05). The regression equations of the 3 factors were fitted through the processing by Design Expert 8.0.6 (experimental design expert) software. Based on the results of examination, we found that the fitting of the equations was good, the best parameter combination was adsorption angle of 20°, negative pressure value of 660-720 Pa and forward velocity of 0.72-0.76 m/s, and under the optimal condition, the qualified index was greater than 90.2, the missing index was less than 4.9, and the multiple index was less than 5.3. The pneumatic cylinder precision seed-metering device met the standard and requirements by comparing the results with the national standard and notoginseng planting requirements. This approach of research is suitable for the exploitation of notoginseng seed-metering, and provides a theoretical reference for the design of pneumatic cylinder precision seed-metering device for Panax notoginseng.

       

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