Кандидат технических наук, доцент Кафедра процессов и оборудования перерабатывающих и пищевых производств им. проф. П. С. Берника Винницкий национальный аграрный университет ул. Солнечная, 3, г. Винница,

The influence of parameters of technological loading, properties of grain mixes and constructive parameters of sieves on the values of the formed equivalent stresses and their durability is given. The change in equivalent stresses was studied both on serial sieves with basic triangular holes and on sieves with activators -innovative holes in the form of an epicycloid. Finite element method based on Pro/ENGINEER product and research data is used to predict the durability of perforated sieves. It was found that the use of activators on sieves, due to their innovative forms, increases the durability of the perforated sieve by 12.3%. The developed technique allows to analyze different designs of sieve openings by the criterion of their durability.

The article clarifies an approximate variant for calculating the temperature in an inhomogeneous layer cell without a clear boundary under the assumption of significant distance in its center between the upper and lower ends of the silo when heat exchange conditions have little effect on the development of temperature in the layer cell due to poor thermal conductivity. The normal Gaussian law concerning distribution of thermal sources in the cell on an axis of a silo is accepted. The integral cosine of the Fourier transform is used to construct the analytical solution of the nonstationary thermal conductivity problem. A compact formula for calculating the increase in excess temperature in the center of the self-heating cell over time is derived and used to identify the parameters of the cell. The change in temperature at other points of the raw material is expressed through incomplete gamma function that is reduced to the probability integral. Calculations show that for the selected distribution of thermal sources, the temperature increase slows down rapidly with separation from the center of the cell. The possibility of determining the pattern distribution of the localized field of excess ambient temperature over time is proved. Examples of density identification of thermal sources are given. After identification, the calculation formulas become consistent with the experiment and suitable for the theoretical prediction of temperature rise in the raw material. The approbation of the proposed mathematical expressions to identify the parameters of the self-heating process of raw materials showed high accuracy relative to experimental data with a deviation of 0.01–0.015%. It is possible not only to determine the parameters of the self-heating cell but also to predict the time of reaching a flammable temperature in it.

Separation of seed mixtures for the purpose of their purification or calibration by fractions is a mandatory technological operation in the processing of most crops. Due to its properties, the process of separation of seed mixtures of individual crops has undefined parameters or low efficiency of its flow. A similar seed material is safflower, the parameters of the purification process of which were determined in the work taking into account different methods of separation of the components of the mixture. The work involves determining the parameters of the holes of the sieves and the scheme of their installation during the separation of the seed mixture of safflower, provided the maximum quality of seeds. For this purpose, the dimensional characteristics of safflower seeds and characteristic impurities were determined, which allowed to determine the possibilities of their qualitative separation. As a result of experiments, variation curves of dimensional characteristics of safflower seed mixture components in thickness and width were established. To imitate hard-to-separate components, winter wheat and pea grains were added to safflower seeds. The efficiency of sieve separation was also determined taking into account different types of sieve openings. Studies of the process of purification of safflower seed mixture were performed both on traditional flat stamped sieves and on the proposed sieves with activators. A study on the separation of safflower seed mixtures on traditional sieves with round holes with a diameter of 5.0 mm and rectangular holes with a width of 3.0 mm has been carried out. For the first time, a sieve with five-petalled epicycloid and volume activators was used to clean the seed mixture, which, thanks to the innovative design, allows us to increase the efficiency of the separation process. For the first time, a well-grounded method of determining the coefficient, which comprehensively takes into account the parameters of holes and jumpers, can be used to optimize the parameters of seed and grain cleaning machines. The separation efficiency of the safflower seed mixture was determined both by the content of fractions and by the indicators of 1000 seed weight, germination energy and seed germination. It has been found that to increase the productivity and quality of separation, it is advisable to use sieves with sieve activators: the upper sieve with five-petalled epicycloid activators 5 mm, and the lower with elongated holes 3 mm wide as well as volume activators.