Studies of a Rotary–Centrifugal Grain Grinder Using a Multifactorial Experimental Design Method

Abstract

A scientific and technical literature review on machines designed to grind fodder grain revealed that the existing designs of grinding machines—those based on destruction by impact, cutting, or chipping—have various drawbacks. Some disadvantages include high metal and energy intensity, an uneven particle size distribution of the ground (crushed) product, a high percentage of dust fraction, the rapid wear of work tools (units), and heating of the product. To eliminate most of the identified shortcomings, the design of a rotary–centrifugal grain grinder is proposed in this paper. The optimization of the grinder’s working process was carried out using experimental design methodology. The following factors were studied: the grain material feed, rotor speed (rpm), opening of the separating surface, number of knives (blades) on the inner and outer rings, technical conditions of the knives (sharpened or unsharpened), and the presence of a special insert that is installed in the radial grooves of the distribution bowl. The optimization criteria were based on the amount of electricity consumed by and the performance of the rotary–centrifugal grain grinder. The quality of performance was quantified by the finished product, based on the percentage of particles larger than 3 mm in size. An analysis of the results of the multifactorial experiment allowed us to establish a relationship (interaction) between the factors and their influence on the optimization criteria, as well as to determine the most significant factors and to define further directions for the research of a centrifugal–rotary grain grinder. From our experimental results, we found that the grinder is underutilized in the selected range of factor variation. Furthermore, the number of knives installed at the second stage of the grinder, the gap (clearance) of the separating surface, and the technical condition of the knives are among the most important factors influencing the power consumption and the quality of the resulting product. A reduction in the number of knives at the first stage has a positive effect on all the selected optimization criteria; and by varying the factors in the selected range, it is possible to obtain a product corresponding to medium and coarse grinding.

Investigation of the continuous mode of mixing when changing the rotation frequency of the impeller of the mixing plant

“…A study of installations based on vane pumps [1,2,3,4,5,6,7,8], it was found that the rotational speed n from 1750 to 3000 min -1 is not always effective, although even with these values high performance indicators. Therefore, in experimental studies, we proceed from the fact that we take synchronous speeds of rotation of the electric motor (respectively, it will be the same for the impeller) n = 750, 1000 and 1500 min -1 , but for more accurate readings we take a step of 250 min -1 , respectively, points will be next n=750, 1000, 1250, 1500 and 1750 min -1 .…”

Studying the operational efficiency of the centrifugal-impact feed grain crusher of the new design

“…In the centrifugal-impact shredder, the rotor's blade is used to accelerate a grain to a speed of 80...100 m/s to be destroyed by a blow against a stationary reflector on the deck. In this case, grain destruction is much more effective than when grinding with free hammer blows [5,6]. This produces a shredded material with a more uniform granulometric composition that meets zootechnical requirements while the specific energy consumption is 3.3...4.5 kWh/t [6][7][8].…”

“…It is possible to obtain shredded material with an aligned granulometric composition that meets zoo-technical requirements when grinding grain at centrifugal-impact crushers [5,6]; this ensures the specific energy consumption within 3.3…4.5 kWh/t [6][7][8].…”

Simulation Analysis and Multiobjective Optimization of Pulverization Process of Seed-Used Watermelon Peel Pulverizer Based on EDEM

“…While the results offer insights for low-noise grass crusher design, the crushing performance of the grass crusher has not been correspondingly investigated and analyzed. Marczuk, A. et al [11] presented a design for a rotary centrifugal grain mill aimed at addressing issues related to uneven particle size distribution and high dust content in milled products. They utilized a multifactor experimental method to construct a prediction model of factors and indicators, enabling the determination of optimal parameter combinations.…”