Design and experiment of fertilizer distribution apparatus with double-level screws

Abstract: In order to meet the physical requirements of fertilizer and improve fertilizing effects, a fertilizer distribution apparatus with double-level screws was designed. It mainly consists of a work bin, a screw of steady flow transportation, a fertilizing screw and a driving chain. The screw of steady flow transportation provides stable and adequate fertilizing flow for the fertilizing screw, mixes fertilizer and prevents fertilizer arching in the work bin, and ensures that the filling rate of the fertilizing screw is very close to 1. Through establishing mathematical models of per lap fertilizer amounts for the fertilizing screw, the fertilizing principle of fertilizer distribution apparatus with double-level screws was studied, and related parameters were analyzed as well. In addition, experiments were conducted to test and evaluate the working performance of the double-level screw fertilizer distribution apparatus. Three types of fertilizing screws were designed to meet the actual production requirements of fertilizing (20-100 kg/667m2) based on mathematical models. Test results show that, 1) In 10-200 r/min speed range, for Batian compound fertilizer, rice specific fertilizer, and Batian compound fertilizer and rice specific fertilizer after the absorption of moisture, the fertilizer amount per minute of the fertilizer distribution apparatus with double-level screws increases with increased speed, showing a linear relationship with a correlation coefficient of larger than 0.998. Therefore, the fertilizer distribution apparatus with double-level screws can adjust the fertilizer amounts by varying the speeding of fertilizing screw to meet the requirements of different fertilization. 2) In 10-200 r/min speed range, the standard deviation, range and variation coefficient of the per lap fertilizer amounts are relatively small for 3 types of fertilizing screws. The variation coefficient of the per lap fertilizer amounts is less than 0.025 for Batian compound fertilizer with the moisture content of 2% and the rice specific fertilizer with the moisture content of 5.6%. The overall variation coefficient of the per lap fertilizer amounts is not more than 0.040 for Batian compound fertilizer and rice specific fertilizer with higher moisture after the absorption of moisture. The fertilizer distribution apparatus with double-level screws has a better adaptability and good fertilizing effect for above 5 types of fertilizers in 10-200 r/min speed range. 3) In 10-200 r/min speed range, by comparing theoretical fertilizer amount per lap and theoretical filling rate with actual values, respectively, mathematical models of the per lap fertilizer amounts of the fertilizing screw was verified and confirmed. This study can effectively improve the fertilization effect, reduce the fertilizer requirements of morphological characteristics and provide a reference for the research and design of synchronous sowing and fertilizing machine and variable-rate fertilization machine.