Theoretical justification of fruit separation process by a planetary fruit separator

. The article is devoted to the theoretical justification of the process of rolling stems by planetary rollers of the fruit separator in the harvesting of Solanaceae vegetables as reusable as direct full harvest. The article has a theoretical, research character, expressed in the fact that the issue of Solanaceae vegetables harvesting was theoretically considered, the analysis of methods and means for the introduction of dry inorganic substances was given, when considering the process of rolling stems of Solanaceae vegetables as a rolling of elastic-plastic material there were obtained the dependences that determine the kinematic and energy parameters of planetary multi-rolling fruit separators. The type of the proposed design is theoretically justified, its description and the flow of the technological process are given. As a result of the work done, the dependences of the main parameters and values are obtained, which can be used in further work on the study of the parameters and dependencies of the interaction of the fruits of Solanaceae vegetables in interaction with planetary fruit separators.

The research in the field of Solanaceae vegetables harvesting was conducted in Kuban State Agrarian University at the department of "Processes and machines in agribusiness". The work is aimed at the development of working elements of the rotor type for reusable harvesting of Solanaceae vegetables. It is probable, that the present construction allows to improve the qualitative rates of working elements of fruit separators. The bottom of sweet pepper is on a peduncle which is attached to a stem. When separating the fruit, it is necessary to separate the peduncle at the place of its attachment to the stem.
The rupture is provided if the force of compression acts on the peduncle in the transverse direction, and in the longitudinal direction -the tensile force and the variable bending moment in the direction. The combination of these forces and moment is observed in the work of the planetary fruit-separating apparatus. The breaking force of the peduncle in bending tension is reduced by 3-5 times compared to the tension without bending.
The process of main fruit separation is at the third level of the multilevel scheme of justification. Its input parameters are the output parameters of the second level -the operation of the process of rolling stems. The criterion for evaluating this operation is tdthe degree of fruit separation, which should strive to the maximum value. Figure 1 shows the scheme of the influence of forces of normal pressure N, friction T and stretching p on the bottom of the fruit and the peduncle. In the case, if the diameters and working surfaces of paired rollers are the same, the angles of a coverage of the rollers by a stem and a fruit, forces N, T and the resultant forces R for both rollers will be the same, and the bending of the peduncle is absent, and its rupture often occurs in the middle. But diameters and working surfaces of the planetary rollers 3 and 4 in general are in pair and they are different, so 3 4, N3 N4, 3 T4 R3 R4.
To separate the fruit, the following condition must be met: and Ny-sum of projections of forces 3 and 4 and N3and N4 respectively on direction of stem's motion.
The process of separating the fruit from the stem by the planetary roller consists of two stages: stretching the stem and its double-ended bending. Consider the first step. In the result of the relative movement of the rollers 3 and 4 and the impact on the bottom of the fruit of variable forces R3 and R4, the fruit influences a variable moment in magnitude and direction. The peduncle bends and stretches so, that the most tension influences the extreme external or internal fibers in the place of attachment of the peduncle to the fruit. The rupture of the peduncle will take place as only the tension in the place of connection with the fruit will achieve the critical values.
Suppose, that the peduncle is a flexible fiber attached to the middle of the fruit's bottom and the force P is directed along the middle fiber of the peduncle, dn-diameter of fruit: llength of peduncle in the place 5-6; 1-angle between direct 5-6 and 5-7, defining the direction of force , 2 -angle between direct 1-2 and 03-04, defining the position of the fruit's bottom in a working chink.
According to calculations = 0-10°. In the result of projecting of sides of trapezoids 1 356 and 2 456 in the direction 5-6 and O3O4 and transformations we obtain where m-difference of radii of adjacent rollers, m= r4-r3; n -difference between length of peduncle, n = 4 l -r4-r3+m.

R3=
; R4 = We assume that 1and 2 are angles between the directions of the normal pressure N3and N4 and speeds V1 and V2, respectively. If speeds V1 and V2 are directed to angles inside angles of friction 3 and 4, so 1> and 2> 4, rollers 3 and 4 slip along the fruit's bottom, and directions of vectors R3 and R4 are defined by values of angles and 4, and modules R3 and R4 on formulas (5). If 1< and 2< 4, so the direction of vectors R3 and R4 coincide with vectors V1 and V2, respectively. Then, determining the modules R3 and R4 in the formulas (5) and (6) instead of 3 and 4 should be put E1 and 2, respectively. And so, the position of the bottom of fruit at the beginning of contact with the rollers is determined by the ratio of the roller diameters d3 and d4 and the fruit's bottom dn. In turn, values and directions of powers R3 and R4 depend on position of fruit's bottom in a working chink and as well as on values 3 and 4. If 1> and 2> 4, the conditions for non-gripping of fruit by rollers 3 and 4 will be: 3 -2 3 and 4 2 4 where 3 -2 and 4 + 2 -angles, closed between the flatness of fruit's bottom and directions of forces N3 and N4 respectively. If 1< 3 and 2 < 4 , the conditions for gripping of fruit by rollers 3 and 4: Period of fruit separation from the stem by planetary rollers t0 was defined by the formula: where 0-relative elongation of peduncle; l-length of peduncle; -radius of initial circumference of the rolling of the drum 1 along the drum 2, = , A = -distance between centers of drums 1 and 2; Vc -speed of stem. Power which is necessary for fruit's separation from the stem by rollers of two-drum device Wn, is equal: where -amount of stems which are simultaneously in the working chink; naverage amount of fruits on the stem; 3 and 4 -moment of resultant forces R3 and R4 relatively to momentary axes of rotation of rollers 3 and 4.
Power for fruit's separation by rollers Wq is defined by the formula = where q-mass of one fruit. Thus, it is theoretically defined the rationale of the fruit separation process by the planetary fruit separator. The obtained dependences of the main parameters and values can be used to study similar structures and parameters and dependencies of the interaction of fruits of Solanaceae vegetables in the interaction with planetary fruit separators in a further study.