A laboratory unit has been developed for cleaning carrots, which will improve the quality of cleaning carrots from soil impurities and plant residues. The proposed design of the device for orienting carrots during cleaning.
The key problem in the technological process of harvesting any root crops is the removal and harvesting of tops from their heads on the root. Root crop tops are a valuable product, such as a source of animal feed, green fertiliser, and a suitable raw material for biogas production, and therefore a prerequisite for harvesting them is to completely cut off all the green mass from the heads, collect it in a vehicle and transport it to the place of use. The main thing is to ensure that root crops do not have green plant residues on their heads, that the heads themselves are not damaged and that they are not knocked out of the soil. The purpose of this study is to develop and test in production conditions a new combined unit for harvesting root crop tops using an integrated arable wheeled tractor. This study used the methods of machine use in crop production, methods of experimental research and field testing of agricultural machines and evaluation of their performance indicators. As a result of the study, a new design and technological scheme for harvesting root crop tops using an integrated arable wheeled tractor of traction class 3 was developed and substantiated. The developed and tested unit performs the technological process steadily and has sufficiently high quality indicators of the tops harvesting. Thus, when using a three-row version of the tops harvesting unit, the amount of cut tops is about 95…98%. The degree of damage to the heads of root crops does not exceed the norms established by agricultural requirements (no more than 5%). However, during the operation of this tops harvester, there is too high a percentage (60…65%) of grinding of tops leaves during its continuous cutting and loading without spear.
Harvesting root crops still poses a challenging problem for the agricultural mechanization industry. Even though the technology of separate harvesting of tops and roots has undoubted advantages, the quality of the final product, i.e. roots, depends significantly on the accuracy of cutting tops from their heads to the roots and the thoroughness of their final cleaning from residues. One of the ways to solve this problem is to create improved constructions of peelers and their further testing, experimental and theoretical studies to determine their optimal structural and kinematic parameters. To implement the above, a new mathematical model was constructed, the study of which made it possible to assess the influence of the construction parameters of the root crop head cleaner from the residues of tops on the root on the indicators of its oscillatory process in the longitudinal-vertical plane when moving along uneven soil surfaces. Numerical calculations of the obtained mathematical model were carried out on a PC using the PTC Mathcad 15 software environment and the previously determined input numerical parameters. The amplitude-frequency and phase-frequency characteristics were constructed, which made it possible to determine the optimal parameters of this oscillatory system. Based on the mathematical modelling performed, the influence of irregularities in the longitudinal profile of the soil surface on the angular oscillations of the cleaner, as well as the influence of different values of the stiffness coefficient c and the damping coefficient μ of its two copy wheels, as well as the length l, or the longitudinal coordinate of their placement on the cleaner frame, was first of all determined. The mathematical modelling of the oscillatory movements of the cleaner made it possible to establish that the value of the stiffness coefficient c of the pneumatic tires of its trailing wheels should be not less than 315 kNm–1, which is ensured by the air pressure in its tires, which should be equal to 135 kPa. In addition, it has been established that the change in the value of the coefficient μ of damping of the tires of the cleaner’s tracking wheels should be in the following range 350…1350 Nsm–1 and this parameter does not affect the amplitude and phase frequency characteristics of oscillations under the influence of oscillations of the ordinates of the longitudinal profile of field surface irregularities in the frequency range 0…24 s–1. Also, the influence of oscillations of the longitudinal profile ordinates of the field in the specified frequency range of 0…24 s–1 depends little on the change in the value of the longitudinal coordinate l of the location of its tracing wheels. Therefore, the placement of the tracing wheels on the frame should be determined based on the constructional features of the cleaner.
Cleaning of root crop bodies from impurities during their digging from the soil is a complex and energy-consuming technological process. Therefore, the development of new types of cleaners of root crop pile from impurities, in particular spiral type cleaners, allowing to intensify this process and improve the quality of cleaning is a step to successfully overcome this problem. The paper presents a study of the technological process of sifting soil particles during the cleaning of the heap of root crops with a spiral-type cleaner. In particular, a calculated mathematical model was constructed, which reflects the movement along the spiral of the body cleaner (soil particles) of variable mass. Using the differential equation of volume change, the differential equation of mass change, i.e. the mass that is sifted through the coils of the spiral cleaner was compiled. Based on the theoretical study, it was found that many factors influence the intensity of soil sifting on the spiral separator – the initial mass of particles, the design dimensions of the cleaner, frictional properties of the surface, angular parameters of body placement on the spiral surface and angular velocity of the spiral roller rotation, and the intensity of these parameters has been studied. Using PC, graphical dependences of the intensity of soil sieving on the angle of rotation of the cleaning spiral when changing the angular velocity of the spiral were constructed.