Search

Saabunud / Received 06.07.2020 ; Aktsepteeritud / Accepted 03.08.2020 ; Avaldatud veebis / Published online 03.08.2020 ; Vastutav autor / Corresponding author: Jüri Olt e-mail: jyri.olt@emu.ee Operations to apply mineral fertilisers to the soil are an important part of practically every form of agricultural technology. The current global trend of transitioning to bridge and gantry-type agricultural systems leaves the unanswered relevant question of the effectiveness of the technological process of applying mineral fertilisers to the soil. This is relevant because, in gantry agriculture, a section of the arable soil is separated as an engineering area. This is why the main difference in gantry agriculture from traditional methods of the bulk spreading of fertiliser onto a field is that, with gantry systems, the amount of fertiliser that lands within the engineering zone are limited. This significantly affects the manufacturing costs involved in the entire area of agricultural technology and, as a result, the production costs of the end product. This study aimed to research the patterns that are apparent in affecting the parameters involved in the use of gantry-type equipment when applying fertiliser with the parameters and operational modes of a specially-developed electric spreader of mineral fertilisers. The physical object of the study was the agricultural gantry equipment that had been developed by the authors. This equipment, which is used for spreading fertiliser, was in the form of a tractor-mounted, suspended, single-disc spreader which was known as JarMet, and which had especially been modified to run from an electrical supply. The study indicated that the biggest influence on the speed of rotation of the centrifugal disc in the mineral fertiliser spreader stems from its height above the ground, the distance of track of the agricultural gantry itself, and the aerodynamic coefficient of the fertiliser. It was determined that, for the agricultural gantry with a distance of tracks of 3.5 m, a sufficient angular speed of the single-disc centrifugal tool is 15.5 rad·s−1, with a power demand for driving this at 0.35 kW·h. When using agricultural gantries of this type with an extended track width of up to 6 m, the necessary angular speed of the centrifugal tool for spreading fertiliser increases exponentially, to 318.2 rad·s−1, with the power demand for driving it increasing to the third power.

The cultivation and harvesting of sugar beets (roots and leaves) is one of the most labour and energy consuming work processes in the agricultural industry. The most important task in sugar beet farming is to improve the quality of sugar beet root crop harvesting and reduce energy costs for harvesting. This primarily concerns reductions in losses and damage of root crops, as well as a reduction in their contamination; in this case, the loss of fertile soil will be excluded, which will be removed from the fields together with the contaminated root crops. These issues present a multifaceted scientific and technical problem, which must be solved by searching for new working elements of sugar beet harvesting machines. Despite the modern level of construction of beet harvesters and their working bodies that has been achieved, there is a need to find further ways to improve them. Further research should deal with the improvement of general constructional schemes of new beet harvesters, with thorough theoretical justification of their constructions and technological parameters. The newly developed theories of functioning of improved constructions of sugar beet harvesters and their working bodies require thorough experimental verification. This will give grounds to use the obtained theoretical dependences for the final goal—analysis and generalisation of their rational parameters. Theoretical research must play a fundamental role in the mechanical and technological substantiation of the root lifting process. It must be used as the basis for developing rational kinematic and dynamic operation conditions in order to achieve the required quality of the performed work process as well as streamlined energy consumption. At the modern stage of the development of agricultural mechanisms, the methods of mathematical model generation based on the use of the theoretical and analytical mechanics and the application of up-to-date mathematical tools and computer technology have to be employed in the analysis and synthesis of the parameters of implements and agricultural machines overall. Thus, the modern methods of theoretical research into the implements of sugar beet harvesters have to be based, first, on the state-of-the-art perception of the principles of the processes that take place when the roots are lifted from the soil and, second, on the possibility of describing these processes more comprehensively and systematically with the use of modern mechanical and mathematical methods. Undoubtedly, such a description only has to be provided for the principal and essential moments of the mentioned processes, while the insignificant and incidental factors must be completely neglected. Further, on the basis of the analytically determined rational parameters of the lifting implements of sugar beet harvesters, which are subsequently experimentally validated and refined, highly reliable prototypes must be designed, which then have to be widely used by the agricultural engineering plants and companies. Therefore, this treatise presents the fundamentals of a new theory of the lifting tools of sugar beet harvesters—in particular, vibrational lifters based on the modern methods of mechanics and mathematics. It has been a long time since the first attempts were made (in the 1970s) to analytically describe the oscillating processes that take place during the vibrational lifting of sugar beet roots from the soil. The theory of the vibrational lifting of root crops has, overall, not been developed to a sufficient extent; the mathematical model specifically used for the process of root extraction from the soil by the vibrational lifter has not been devised. Until recently, it had been assumed that the experimental methods of determining the amplitude and frequency of oscillation of the vibrational faces—which could only have relatively limited values, subject to the reliability of the vibrational actuator—completely ensured the optimality of this whole process. However, at the present time, under the conditions of significant improvements in the reliability of designs and changes in the kinematic parameters of harvesting (for example, the increase in the travel speed to levels of up to 2.5 m·s−1 ), the obtained values of the parameters of vibrational lifters can by no means be considered optimal. Therefore, a goal has been set to develop, first of all, a new theory of vibrational root lifting based on the generation of mathematical models, which would describe the interaction between the digging shares on the one hand and the root’s body and the soil on the other hand. At the same time, the theory has to provide the mathematical descriptions of all stages of said interaction, starting from the stage of the lifter approaching the root body fixed in the soil (as in elastic medium), proceeding to the interaction of the root body with only one digging share of the lifter (asymmetric gripping of the root), followed by the interaction with both the share surfaces (symmetric gripping), and finally the eventual translation of the root along the lifting tool’s throat towards the level of the soil surface. Additionally, as a matter of principle, the theory needs to consider different (possible) directions of the oscillating motions of the digging shares of the vibrational attachment—i.e., the longitudinal and transverse ones.

Saabunud / Received 08.10.2020 ; Aktsepteeritud / Accepted 15.12.2020 ; Avaldatud veebis / Published online 31.12.2020 ; Vastutav autor / Corresponding author: Jüri Olt yri.olt@emu.ee The experimental investigations carried out in field production conditions have proved that the process of cleaning potato tubers from extraneous material with the use of a spiral separator takes place due to the active conveyance of the heap by the turns of the cantilever mounted cleaning spiral springs. The cleaning spiral springs not only rotate at the set angular velocity, but simultaneously their cantilevered ends perform oscillatory motion, which arises due to the deflection of their longitudinal axes under the action of the weight of the potato heap fed into the work zone of the separator. The results obtained in the process of the field experiment investigations carried out by the authors have provided for obtaining the relations that enable selecting the optimum design and kinematic parameters of the spiral-type potato cleaning devices for the targeted separation rate and, accordingly, estimating their impact on the quality of the performed work process.

Метою статті є підвищення ефективності кормовиробництва шляхом теоретичного та експериментального обґрунтування науково-технічних основ проектування гвинтових грануляторів кормів з гвинтами, параметри яких змінюються за їх довжиною. Теоретичні дослідження здійснювались шляхом аналізу взаємодії робочих органів гранулятора з технологічним матеріалом із застосуванням методів теоретичної механіки та механіки суцільного середовища, диференціальних та інтегральних обчислень, математичного моделювання. Експериментальні дослідження виконувались у лабораторних та виробничих умовах на основі планування багатофакторних експериментів. Аналітичні розрахунки й аналіз експериментальних даних здійснювались з використанням відповідного програмного забезпечення. В роботі розглянуто рух елементарного об’єму кормової сировини в розгортці каналу гвинта гранулятора кормів. Запропоновано умову приведення гвинтів з каналами поширених форм до ідеалізованої моделі гвинта з каналом прямокутної форми. Встановлено вплив конструкційно-режимних параметрів гранулятора та фізико-механічних властивостей кормової сировини на основні показники його роботи. В результаті теоретичних та експериментальних досліджень було створено науково-технічні основи проектування гвинтових грануляторів кормів з гвинтами, параметри яких змінюються за їх довжиною. В загальному вигляді були отримані вирази тиску в каналі гвинта гранулятора, продуктивності, витрат потужності та крутного моменту на привод гвинта гранулятора. Експериментальні дослідження підтвердили адекватність отриманих виразів. Знайдено вираз оптимальної інтенсивності зміни геометричних параметрів гвинтаАдамчук В. В. Обґрунтування параметрів гвинтового гранулятора кормів / В. В. Адамчук, В. В. Братішко // Науковий вісник Національного університету біоресурсів і природокористування України. Серія : Техніка та енергетика АПК. - 2016. - Вип. 254. - С. 253-268. - Режим доступу: http://nbuv.gov.ua/UJRN/nvnau_tech_2016_254_27