Substantiation of the design parameters of a screw for the variable pitch of a press extruder in the preparation of a loose sunflower meal

The purpose of the study is to reduce the energy consumption of extruding sunflower seed waste when obtaining a sunflower meal in loose form on the basis of planning a multifactor experiment. Before the beginning of the experiment, the factors were encoded by performing a linear transformation of the factor space with the transfer of the origin to the center of the experiment and the introduction of new units of measurement along the axes. The natural value of the factor variation interval was determined. Taking into account the review of literature sources, theoretical studies and scientific and technical information, factors of variation were chosen to calculate the density of sunflower meal in the loose form obtained after treating the waste of seeds on a press extruder KMZ-2. After calculating the regression coefficients, a regression equation was obtained describing the density of the sunflower meal in the loose form. A study was made of the homogeneity of the variances of the experimental responses obtained by the Cochran test, and also checked the adequacy of the obtained mathematical model with the help of the Fisher criterion. The angle of conicity of the screw, the pitch of the auger of the 2nd coiling and, to a lesser extent, the 1st coiling, including the pair interaction between the taper angle and the pitch of the screw of the 1st winding, influence the obtaining of the sunflower meal in loose form in the extruder KMZ-2. Based on the results of the three-factor experiment, the optimum design parameters of the variable-pitch screw of the KMZ-2 press-extruder were determined, which have the following values: the cone angle is 30 °, the pitch of the screw of the 2nd coiling is 28 mm, the pitch of the screw of the 1st coiling - 36 mm, which make it possible to obtain a loose sunflower meal with a density of 2139,4 kg / m3 and reduce the energy consumption of extruding sunflower seeds.