颗粒化肥水平气送式螺旋组合可调定量供肥装置设计与试验

为适应不同施肥量要求和实现水平气送式集中排肥器定量变量排肥,该文设计了一种颗粒化肥螺旋组合式集中供肥装置。阐述了颗粒化肥螺旋组合式集中供肥装置的工作原理,基于颗粒化肥的机械物理特性和施肥量要求,提出了倾斜螺旋状型孔结构,确定了其主要结构参数,构建了颗粒化肥组合体在肥料充填区和投肥区的力学模型。应用台架试验研究了螺旋式排肥轮数量和转速对供肥速率及供肥稳定性变异系数的影响。结果表明:倾斜螺旋状型孔结构有利于充肥和排肥;螺旋式排肥轮数量和转速分别为1~4个和10~40 r/min条件下,供肥速率随螺旋式排肥轮数量与转速增加而增加,供肥速率范围为912.67~13 164.26 g/min。螺旋组合式集中供肥装置能适应不同机械物理特性参数的颗粒化肥,3种颗粒化肥的供肥速率之间的差值低于5%。构建了螺旋式排肥轮数量和转速与供肥速率的回归预测模型,在目标施肥量150~750 kg/hm2和拖拉机前进速度2.52~5.88 km/h条件下,供肥速率试验值与模型预测值的偏差在3%以内,供肥稳定性变异系数低于1.0%。田间试验结果表明,颗粒化肥实际施用量与模型预测值相对误差为3.54%。该研究提出的倾斜螺旋状型孔和组合排肥轮结构可满足农业生产的变量、定量集中供肥要求,可为颗粒化肥水平气送式集中排肥器结构设计提供参考。

Design and experiment of horizontal pneumatic screw combination adjustable quantitative fertilizer feeding device for granular fertilizer

Abstract: Nutrients including the elements of N, P and K are?beneficial?to the growth and yield of crops. Reducing the application amount of chemical fertilizer and increasing the utilization rate have become the important ways and means of high quality and high efficiency green agriculture. Granular fertilizer has been widely used in agricultural production because of its low fluidity, strong?hygroscopicity and cohesion. Meanwhile, the amount of fertilizer applied depends on the crops, the fertilization application time, and the fertilizer varieties. In order to adjust the requirements of fertilization and precision fertilization, the horizontal pneumatic centralized feeder of fertilizer was developed. The fertilizing device is the core part of the horizontal pneumatic centralized feeder. According to the mechanical and physical properties, and fertilizer requirements of granular fertilizers, the inclined screw-type model-hole and combined fertilizer feeding unit was designed. The main structural parameters of the inclined screw-type model-hole and the fertilizing unit were determined. The bottom width, upper width and depth of model-hole were 12.0 mm, 30.0 mm and 18.0 mm, respectively. The left inclined angle, right inclined angle and number of screw-type model-hole was 24°, 37° and 6, respectively. The helical pitch, helix?angle and length of fertilizer feeding unit were 450 mm, 60° and 40 mm, respectively. The number of fertilizing unit could be adjusted from 1 to 4. The amount of fertilizer applied varied with the number of fertilizing units and the rotational speed. The mechanical models of fertilizer combination in fertilizer filling and feeding zone were established. The results showed that filling and feeding performance of fertilizer could be improved significantly by tilting angle between left and right. The fertilization performance experiments were performed in the bench test. The effects of fertilization unit number of and rotation speed on fertilizer application and coefficient of variation were studied using Zhushang Fertilizer. Furthermore, the fertilizer adaptability of fertilization device was studied with Zhushang Fertilizer, Sanning Fertilizer and Yunding Fertilizer. The results showed that: 1) When the fertilization unit number and rotational speed were 1-4 and 10-40 r/min, respectively, the fertilization amount increased with the increase of number of fertilization unit number and rotational speed. The range of fertilizer feeding rate was 912.67-13 164.26 g/min. 2) The amount of fertilizer application was significantly affected by the fertilizer types, rotation speed and interaction between fertilizer types and rotation speed. With the same rotation speed of 10-30 r/min, the fertilizer feeding rate of Sanning Fertilizer was the largest, while that of Yunding Fertilizer was the lowest. The difference of fertilizer feeding rate among three fertilizer types was less than 5%. It indicated that the fertilizer feeding device could be applied to different compound granular fertilizer. 3) The quadratic regression predicted model of fertilizer amount was established with the factors of fertilization unit number and rotational speed. The determination coefficient of the regression prediction model was 0.995 8, which indicated that the prediction model was feasible. The fertilizer feeding rate was studied under the condition of target fertilizer application range of 150-750 kg/hm2 and tractor velocity of 2.52-5.88 km/h. The deviations between the experimental value and the predicted?value of fertilizer feeding rate were not more than 3%. In addition, the coefficients of variation of fertilizer feeding rate in each treatment were less than 1.0%. The results showed that the model can accurately predict the fertilizer feeding rate and calculate the fertilizer feeding unit number and rotational speed. The field experiment showed that the relative error between the fertilizer feeding amount and the theoretical value was 3.54%. The structure of the inclined screw-type model-hole and combined fertilizer feeding unit can realize the adjustment of fertilizer feeding rate in a wide range for granular fertilizer. The fertilizer feeding performance of fertilizer feeding device could meet the requirements of fertilizer application amount and fertilizer feeding stability. This research can provide the basis for the structue design of horizontal pneumatic centralized feeder and variable-rate precision fertilization.