The production of biofuel pellets requires significant energy consumption during their production. At the primary technological stage of production: grinding of solid vegetable waste (SVW), electricity costs can be, depending on the physical and mechanical characteristics of SVW, 40… 60% of the total electricity consumed for the production of pellets. Significant losses of electric energy are observed during grinding due to uneven loading of the shredder and operation of the electric motor of its drive in constantly changing modes. This is especially true for small productions when downloading is done manually. This paper proposes a method and algorithm for determining the maximum values of the energy efficiency of the SRW grinding system for the production of biofuel pellets as a function of the load factor of the electric motor of the working machine at different values of applied voltage. As a result of research of an asynchronous electric motor with a nominal power of 4 kW SVW shredder during its operation according to the loading schedule during the eight-hour work shift provided by the farm, it was determined that control of applied voltage at variable loads will reduce energy consumption and increase the energy efficiency of the shredder by 4…6%. According to the results of research, it is proposed to develop a device for controlling the magnitude of the applied voltage at variable loads, the implementation of which will reduce energy consumption by the shredder drive. The proposed technique can also be used in the diagnosis of the electric motor of the shredder, which is in the process of operation of the technological line of production of pellets.
During operation, the hinge connections of mine supports practically stop rotating. This is due to the fact that, as a result of the aggressive mine water and strong dustiness, the diametrical clearance of 1-2 mm between the axis and the bushing is tightly filled with oxides and coal dust, especially in the connections of the base. This circumstance leads to the fact that the axes (pins) in the hinges lose their mobility and require significant effort for their dismantling. To repair the mechanized mine support, it is necessary to dismantle the hinge connections, which are formed by axes and holes in levers (traverses), base ears, and overlaps. Currently, the dismantling of hinge connections of mine supports is carried out using manual impact tools. This operation is extremely labor-intensive, physically heavy, and belongs to hazardous work. The goal of the study is to improve the working conditions of the operator during the dismantling process of axes in hinge connections of mine supports by using a mechanized specialized hydraulic press. To achieve the set goal, the following tasks must be solved: to determine the maximum permissible disassembly force of the axes, taking into account the strength of the load-bearing structure elements; to develop a concept of a mechanized hydraulic press, including the composition of the installation, the general technical description, the principle of operation, the kinematic scheme, and the tool. Studies have been carried out on the deformation modeling of mine support elements under load using the SOLIDWORKS Simulation calculation module to determine the maximum permissible disassembly force of the axes. It has been shown that the disassembly load of the shaft support axis with a force of more than 1000 kN leads to the loss of the structural strength reserve, which is unacceptable. An effective technology for dismantling the axes of a mechanized mine support has been proposed. A concept of an original specialized hydraulic press "Kit-100" for dismantling axes has been developed, which allows replacing the physically heavy and dangerous work of the operator with a lighter, mechanized process.
The article presents the analysis of statistical data of the causes of breakages and leaks in water pipes of the distribution network of Kropyvnytskyi. Breakage statistics for pipelines with a diameter of 25 to 1100 mm during the last five years were calculated. As a result of segmental analysis, it was found that the main types of damage to the pipes of water supply system are through fistulas of steel pipes – 54.4% and corrosion – 25.6%; loss of integrity of cast iron pipes on joints – 9.7%, fractures and cracks of cast iron pipes – 6.1%; fractures in joints of polyethylene pipes and other damages – 4.2%. To characterize the reliability of the municipal water supply networks, the pipeline failure flow parameter ω was used. It was defined as the ratio of the number of failures of the water supply network section to the observation period and the length of pipe network sections of the corresponding diameter. The calculation of interval estimates for the failure rate parameter ωо for steel and cast iron pipes of the water distribution network of Kropyvnytskyi was carried out. According to the operational organization 84% of the network was laid using these pipes and analytical expressions were obtained to determine average values of ω0ср depending on their diameter. Significantly higher values of ω0ср were noted in comparison with similar ones given in the literature for other cities, which can be explained by a significant excess of the standard service life of 85% of steel and 50% of cast iron pipes in the water supply network of Kropyvnytskyi. To increase the reliability of water supply networks, it is recommended to implement the experience of European countries and replace 2% of the network per year and use polyethylene pipes. To reduce the failure factor of water supply networks, particularly in those areas where overtime pipes are used, the expediency of partial installation of water-air dampers for pressure fluctuations directly in the pipeline, in which there is a gradual and complete damping of the shock wave. Approbation of a prototype of a hydraulic shock absorber of this design was carried out in the hydraulics laboratory at Central Ukrainian National Technical University and its efficiency and high efficiency at full shock wave damping was confirmed.
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