No abstract

The authors noted the disadvantages of the 3-wheel universal row-crop tractor. To eliminate them, LLC Design and Technological Center for Agricultural Engineering developed a 4-wheel universal row-crop tractor with variable ground clearance.(Research purpose) To determine the pressure change in the hydraulic system and the transfer time of the rear axle from one type of clearance to another.(Materials and methods) The authors showed that the rear axle clearance could be changed using a special mechanism - with minimal labor costs, without the use of lifting equipment and assembly and dismantling works. They explained that the mechanism was driven by a working hydraulic cylinder. The experiments were carried out on a prototype tractor with adjustable ground clearance, equipped with a separate-aggregate hinged system at an engine speed of 1200-2000 rpm (revolutions per minute). M10G2K oil was used in the hydraulic system, heating it to 65 degrees Celsius (at an ambient temperature of 33-35 degrees Celsius).(Results and discussion) The hydraulic system consisted of an NSh-32 hydraulic pump, a P80 hydraulic valve, two Ts50-200 working hydraulic cylinders, a double-acting hydraulic lock, a hydraulic tank, filters, hoses and high pressure pipes. At the inlet and outlet channels of the working hydraulic cylinders, which activated the mechanism for changing the rear axle clearance, hydraulic locks were installed, and diaphragm pressure sensors model SS302 from Sendor Sensor with a measurement range from 0 to 40 megapascals were placed along the hydraulic line connecting the hydraulic locks with the hydraulic valve.(Conclusions) The authors determined that the time for transferring the rear axle from low clearance to high was 2.2-4.4 seconds, and the pressure in the hydraulic system was 3.8-16.4 megapascals at an engine speed of 1300-2000 rpm. It was found that when transferring from high to low ground clearance, these indicators amounted to 1.0-1.4 seconds and 0.99-9.90 megapascals.

To eliminate the shortcomings of serial fan sprayers, the JV “Agrikhim” developed a universal sprayer that treats crops based on controlled airborne flows introduced simultaneously within ± 90 0 from the sprayer’s symmetry axis (a total of 180 0) around the entire perimeter of the treatment area the entire width of the machine. The obtained dependences and the nomogram built on their basis allow setting the required rate of application of the working solution at a given speed and diameter of the spray tip of the sprayer by adjusting the pressure when the working solution enters the spray tip.

The authors noted the disadvantages of fan sprayers such as OVH-600 and VP-1, associated with uneven application of pesticides due to the oscillatory motion of the working parts, especially in the junction of adjacent passages. (Research purpose) To increase the uniformity of the pesticide solution application over the entire width of the fan sprayer. (Materials and methods) The JV «Agriхim» developed a universal fan sprayer designed for the treatment of field crops, orchards and vineyards controlled by air-droplet flow. It was shown that the number of nozzles depends on the technological scheme of operation and the width of the sprayer. (Results and discussion) The authors determined the optimal number of injectors – 25 pieces. Depending on the flow rate of the working solution, three groups of tips were distinguished. (Conclusions) The authors revealed that the new design eliminates oscillatory movements of the working parts of the sprayer, a significant width (24 meters vs. 16 meters in production models) allows to increase dramatically the productivity of work, and the number of changeovers is minimized. They simplified and cheapened the design of the sprayer due to the rejection of a number of kinematic pairs and drives. They increased reliability of the unit, eliminating rubbing and moving parts and components. They presented the layout of 25 nozzles for high-quality pesticide treatment: 5 rear central nozzles were installed on the air ducts at an angle relative to the soil surface, and on the opposite direction of the air ducts placed 3 and 7 nozzles in each side of the axis of symmetry of the sprayer. It was calculated that the rate of flow of the working fluid in the range of 100-500 liters per hectare can be adjusted by changing the pressure in the system from 2 to 8 bar and the working speed from 3 to 7 kilometers per hour.