Experimental Study and Optimization of Shredding Speed to Improve the Efficiency of Small-Sized Disc Shredder for Plant Residues

Introduction. Utilization of plant residues in gardening is an important problem, and using small-sized shredders is an effective solution for it. Existing small-sized shredders of branches and vines often demonstrate poor performance and high energy consumption that restricts the application of them in small farms. The effect of shredding speed on the performance and energy consumption of the shredders is insufficiently studied and the available data are contradictory. The study focuses on finding the optimal operating modes for a disc shredder operation to minimize energy consumption while achieving the required performance.The Aim of the Study. The study is aimed at substantiating the design and operating parameters of a small-sized shredder by determining the dependencies of the effect of the shredding speed of the shredder working element on the disk shredder performance and energy consumption.Materials and Methods. The studies were conducted on a specially designed laboratory setup, which was a small-sized disc shredder. For each experiment, there were taken 15 samples of apple tree branches with a diameter of 10 to 50 mm. The branches were divided into three bunches: up to 20 mm, 20–30 mm and 30–50 mm. The mass fraction of moisture in the samples was 45–50%, and the temperature of the wood did not fall below 20°C. For each experiment there were recorded the following parameters: the time of shredding each sample, the setup idle run time, the mass of shredded wood, and energy consumption during the shredding process. The experiments were carried out foreach of the three bunches of branches at three different rotation speeds of the working element and three variants of its mass. There were conducted 135 experiments. The data obtained were analyzed using the programs Excel, STATISTICA 10 and Matcad. There were used Student’s t-test to assess the statistical significance of the results and the Shapiro-Wilk test to determine the normality of distribution. The correlation dependence between the indicators was determined using the Pearson correlation coefficient for normally distributed data.Results. There has been developed a regression model to describe the relationship between performance and energy consumption depending on the shredding speed. There have been found dependencies for different branch diameters that made it possible to optimize the operating parameters of the shredder.Discussion and Conclusion. The experimental data have confirmed the importance of optimizing small-sized shredders to increase their efficiency and reduce energy consumption. The results of the work can be used to develop more economical and efficient shredder models, which will have a positive impact on the environmental and economic situation in agriculture.