水稻气力式排种器导向型搅种装置的设计与试验

摘要

为提高水稻气力式精量穴播排种器的排种精度，在该排种器的吸种盘上设计并安装了一种由2个搅种齿组成的导向型搅种装置。以培杂泰丰、Y两优1号种子为对象，采用单因素试验和因素组合对比试验的方法，研究了吸室真空度、吸孔直径与搅种装置对排种器性能的影响。结果表明，排种器安装导向型搅种装置后，工作转速显著提高，对工作气流真空度要求降低，性能得到改善；在真空度2.0 kPa、吸种盘转速30 r/min、搅种齿厚度2 mm、搅种齿楔角60°、内侧搅种齿安装角90°、外侧搅种齿间安装角60°以及吸孔直径1.6 mm的最佳排种参数下，排种器对含水率20.7%的Y两优1号破胸芽种排出（3～4粒）/穴的概率为59.48%，≤2粒/穴率为15.03%，≥5粒/穴率为25.49%。试验结果显示导向型搅种装置对籼稻种子存在分离、导向、摩擦和支撑等助吸作用，可提高排种器的排种精度。%　　Due to high tilling capacity and preventing the risk of low seedling emergence rate in the field , generally 3-4 seeds are required for each hole when hybrid pregnant rice seeds were direct seeded to the field by drilling machine. Even though the seeds sprouted and their bud length were less than 3 mm with high moisture content, they were low in liquidity and had irregular shapes making it quite difficult to meet the requirement. In order to solve the problem, a novel pneumatic metering device was designed with group sucking holes plate in a seed metering device, by which 3-4 seeds can be sucked and dropped at the same time. Existing experiments were conducted to investigate the suck characteristic of the group holes on the sucking plate under vacuum, diameter of the holes, and seed-clearing device. The results showed the optimal parameter combination was vacuum at 3.2 kPa and the diameter of the hole at 1.5mm. The results:the≤2 sucked seeds per hill, the (3-4) sucked seeds per hill, and the≥5 sucked seeds per hill were 8.27%, 81.87%, and 9.86%while the sucking plate rotating speed was 8 rpm. In order to improve the device performance, the group sucking holes on the plate were increased from eight to ten, its circular distribution was replaced by a linear distribution, and a kind of oriented churning device that consisted of two churning teeth was set on the plate. The single factor experiments and combination factor contrast experiments were conducted to investigate the suck characteristics of the sucking plate under vacuum, diameter of the holes, and oriented churning device. The experimental equipment consisted of a pneumatic metering device with group holes, a U-shaped manometer, a positive and negative pressure air pipeline, a cut-off valve, and a vortex pump. In the experiments, the rotating speed of the sucking plate was 30 rpm and its diameter was 165 mm, the distance between 3 sucking holes were 6.5mm and 11.5mm while the distance was 65mm between the middle hole and the center of the plate. A fingerlike clearing device was set on the plate while the distance was 118mm between it and the center of the plate;its length was 38mm and its installation angle was 25°. Rice varieties were Indic hybrid, Peizataifeng, and Y-Liangyou 1 pregnant rice seed. Their moisture content (wet basis) were 11.6%-11.9%and 23.93%, their 1000-grain were 22g and 25.2g, and their overall dimensions (length × width × thickness) were 8.94mm×2.30mm×1.94mm and 9.11 mm×2.30 mm×1.87 mm. The experimental results showed the metering device performance was obviously improved after installing the oriented churning device, by which its rotating speed was significantly increased and its air vacuum requirements were reduced on the same precision. To suck Y-Liangyou 1 pregnant rice seed, the optimal parameter combination was the vacuum with 2.0kPa, the rotating speed of the plate at 30 rpm, the wedge angle of the churning tooth at 60°, the thickness of the churning tooth at 2mm, the installation angle of the inner-churning tooth at 90°, the installation angle of the outer-churning tooth at 60°, and the diameter of the hole at 6mm. The (3~4) sucked seeds per hill of the pneumatic seed metering device, ≤2 sucked seeds per hill, and the ≥5 sucked seeds per hill were 59.48%, 15.03%, and 25.49%. The results showed that the seeds were separated, oriented, rubbed, and pushed by churning device that has a good influence to the precision of the pneumatic seed-metering device.