# Experimental Research on Unit Operation for Fruit Crops' Bones Calibration
## 2 Materials and Methods  
The research program provided definition by experimental methods of the optimal values of the parameters for laboratory installation operation mode, enabling the achievement of the required quality of bones calibration [15, 16, 17, 18]. The sieves are the principal working part of the machines for seeds sorting and calibration. They separate seeds into differently sized fractions [19, 20, 21, 22, 23]. The obtaining of high-quality material is provided by the effective sieve operation [24]. The process of bones calibration on the sieves includes the following phases:  
* Moving the bones on the working surface of the sieve;
* Sifting through the holes of the sieve;
* Cleaning the sieves' openings from the bones stuck. The calibration process efficiency depends on the characteristics of these phases [24]. Laboratory unit description. On the basis of the design analysis of the calibration machines of crop seeds, the structural and technological scheme of the unit for calibration of fruit cultures bones, given in Figure 1, was substantiated. The unit consists of the unit sieves part (1), which has movable risers--two front (7) and two rear (8)--being mounted on the frame and swinging in the horizontal plane from the action of the connecting rod (2). On the rear risers (8) the mechanism for adjusting the angle of the sieves' incline is being provided. The drive of the unit sieves part consists of an electric motor (4), a belt drive (5) and a shaft (6), which has a mechanism for adjusting the amplitude of oscillations. Above the unit sieves part, there is a hopper (9) with a sloping board (10), by means of which the bones are conveyed to the sieves. For the removal of bone fractions, the unit sieves part has two gutters (11, 13) and one inclined tray (12). There are three receiving trays (14) for collecting bone fractions. The unit sieves part (Figure 2) consisted of two flat stamped sorting sieves (1 and 2), mounted one below the other. As a result of oscillations of the unit sieves, part of the ball periodically moves into the space under the sieve. According to this arrangement of sieves, the total bones volume was divided into three fractions: large I, medium II and small III. The upper sieve 1 is designed to isolate a large fraction of the bones, and the lower sieve 2--for the middle. Sieves had circular openings, which provided the separation of the bones in width. To clean stuck bones from the holes in the sieve, the ball cleaners were set under the sieves, consisting of rubber balls (4), located on the reflective rod surfaces (3). The balls exert a shock effect on the sieves, knocking the stuck bones out of the holes [25; 26; 27]. According to the results of previous theoretical research, the following optimal values of the parameters of the ball cleaner were obtained [2]:  
* ball diameter \(D=33\) mm;
* distance between the rods \(t=23\) mm;
* height of space under sieve \(H=40\) mm. The method of experimental research provided for determining the optimal values of the parameters of the sieve part of the installation, by which the qualitative separation of the bones into fractions occurs, namely:  
* oscillation frequencies of the sieve part (\(n\));
* oscillation amplitudes of the sieve part (\(A\));  
Figure 1: Structural and technological scheme of the calibration unit. 1—the unit sieves part; 2—connecting rod; 3—frame; 4—electric motor; 5—belt transmission; 6—a shaft with regulation of amplitude of oscillations; 7—front risers; 8—near risers with a mechanism for adjusting the angle of inclination of sieves; 9—a hopper for bones; 10—distribution board; 11, 12,13—trays for removal of bones fractions; 14—receiving trays. Figure 2: Design and technological scheme of arrangement of sorting sieves and ball cleaners. 1—top sorting sieve; 2—lower sorting sieve;3—reflective rod surfaces of ball cleaners; 4—rubber balls; I—large fraction, II—medium fraction; III—small fraction. * the angle of inclination of the sieves and ball cleaners (\(\beta\)).