渐缩式比例施肥器的设计与试验

【目的】解决压差施肥罐施肥质量浓度随时间衰减的问题。【方法】采用在压力罐中设置可变形的肥袋,压力罐、肥袋与主管连接点中间设置减压阀的方法,研制了一种通过压力罐向管道注肥的渐缩式比例施肥器,实现了比例施肥。理论分析了其并联特性,在此基础上试制了样机,开展了性能试验,测试了4种管道工况下施肥质量浓度变化。【结果】可变形肥袋起到了水肥分隔、水肥等量置换作用,其水力系统为并联管道系统,当结构形式一定时,施肥比例是常数,其仅与2个支路管径以及局部损失系数有关,不受来水管道压力、流量变化影响,同一工况、不同时刻出水管道肥液质量浓度最大偏差为4.7%,来水管道工况变化时平均质量浓度最大偏差为3.5%,属于均匀施肥,施肥器的最大水头损失为0.47 m,施肥比例可在0～10%范围内调节。【结论】研制的渐缩式比例施肥具有施肥质量浓度稳定、水头损失小,适合各种管道压力的特点,可应用于设施农业喷灌、滴灌系统加药、施肥。

Design and Test of the Shrinking Proportional Fertilizer Applicator

【Objective】The purpose of this paper is to find a solution of the problem of fertilizer concentration decline with time in pressure difference tank.【Method】A gradually shrinking proportional fertilizer applicator with injecting fertilizer into pipeline was developed, which can be used for proportional fertilization. The adopted was application method to put a deformable fertilizer bags into the pressure tank, in the middle of the connect line of the fertilizer bag, with the main pipeline. Based on the theoretical analysis of its parallel characteristics, a prototype was developed to test the changes of fertilizer concentration under four different pipeline conditions.【Result】The deformable fertilizer bag can separate water and fertilizer, and had an equivalent replacement for the fertilizer and water. It acted as a parallel pipeline system. When the structure of the hydraulic system was decided, the fertilizer proportion was a constant that was only related to the diameter of two branches and the local resistance coefficient. The maximum deviation of fertilizer concentration in the main outlet pipe was 4.7% under the same working condition and in different time. The maximum deviation of the average concentration was 3.5% when the working condition of the incoming water pipeline changed. That was uniform fertilization. The maximum head loss of the fertilizer applicator was 0.47 m, and the fertilization proportion can be adjusted in the range of 0～10%.【Conclusion】The developed gradual shrinkage proportional fertilizer applicator has the characteristics of stable fertilizer concentration and low head loss, while it was also suitable for various pipeline pressures. It can be applied to facility agriculture sprinkling irrigation, drip irrigation system dosing and apply fertilizer.