Equipment Repair Costs Research Articles

Automated solid fuel quality control and monitoring system

The article describes the development of a computer-integrated coal quality management system that allows to increase the service life of heating surfaces in boilers of coal-fired power plants. The need for such a system arises due to erosion caused by abrasive impurities in coal, which leads to deterioration of the boiler infrastructure. Existing methods are mostly manual, time-consuming and error-prone. The aim of the work was to increase the service life of the surface wear resistance of heat exchange tubes of a steam generator of a thermal coal-fired power plant by synthesizing and analyzing a computer-integrated coal quality management system by distributing coal flows between different coal supply sources, unloading conditions and coal quality inspection from suppliers to minimize costs. To achieve this goal, a mathematical model was developed that describes the boiler unit in terms of ash flows in the form of a system of equations. A computer-integrated coal quality control system has been developed that allows to increase the service life of heating surfaces of power boilers by distributing coal flows between coal supply sources and conditions of unloading and checking the quality of coal from suppliers to minimize costs. A computational experiment was conducted to test the operation of the computer-integrated control system and confirm its effectiveness. The results proved the value of the developed computer-integrated control system for increasing the service life of the boiler unit's heating surfaces by timely responding to changes in the quality of coal from different suppliers. It was found that with a computer-integrated control system, the service life of the pipes could be more than doubled (from 3.06 years to 7.39 years). Overall, the introduction of a computer-integrated control system is a transformational solution for managing the distribution of costs between fuel and equipment repair costs. The integrated system, together with the use of mathematical modeling and computational experiments, offers a comprehensive approach to monitoring, predicting, and controlling the factors that affect the durability of heat exchanger tubes. This research makes a significant contribution to the power industry, potentially transforming maintenance and life extension practices for critical infrastructure in thermal power plants. Further researchis needed to refine the system and explore its wider applicability in different operational scenarios.

Methodology of Automated Monitoring and Control of Pump Complex Operation Modes in Conditions of Cavitation Occurrence

The results of solving the problem of increasing the efficiency of an automated pumping complex for pumping liquids in conditions of non-stationary hydraulic processes, such as cavitation, are presented. The difficulty of determining the conditions for the occurrence of cavitation is associated with a large number of parameters, the mutual correlation of which is difficult to determine. It is shown that the methods used in practice in these conditions for monitoring and controlling pumping complexes based on centrifugal pumps and adjacent pipelines have significant disadvantages or solve the problem only partially. A mathematical model of the pump complex operation for operational control of the parameters of cavitation modes based on the similarity of the modes of operation of the centrifugal pump and the movement of the piston through the pipeline is presented, which simplifies the procedure for determining the presence of cavitation. A criterion for determining the efficiency of the pump complex operation mode is proposed based on an integral assessment of the difference between experimental and model data. A methodology for controlling the modes of operation of the pumping complex in the conditions of cavitation is formed. Due to the complexity of the direct calculation of the cavitation volume, a neural network model was proposed, trained based on experimental data. The structure, algorithms and software of the automated control and control system are developed using neural network models and a case-based approach to quickly determine the conditions for the occurrence of cavitation and correct the operating modes of the pumping complex. Decisions based on case — based reasoning are offered to the operator in the form of a "control effect-expected result" pair. The practical implementation of the automated system for monitoring and controlling the operating modes of the pumping complex is carried out in the AppDesigner package of the Matlab mathematical package. The use of the developed automated monitoring and control system provides an increase (restoration) of the pump complex performance in the conditions of cavitation, prevents the destruction of its elements, increases the service life, reduces operating costs and equipment repair costs.

Accounting And Analysis Of Equipment Overhaul Costs

The article proposes to consider the theoretical and methodological foundations of accounting and analysis of equipment overhaul costs. The study of the literature showed that it is necessary to develop recommendations for improving accounting and analysis in real situations at the enterprise. For equipment that needs repair abroad, the authors suggest not to sell it as non-working (scrap metal), but to export and repair it abroad. The procedure for accounting for equipment repair costs abroad is proposed. To improve the analysis of equipment overhaul costs, the authors proposed an algorithm for equipment overhaul cost analysis, which will provide a balanced and reasonable cost estimate. To obtain relevant information for this analysis, the authors have formed requirements for sources of information for financial and economic analysis of non-current assets. The developed proposals will allow companies to improve accounting and analysis of equipment overhaul costs, which in turn will lead to cost savings and strengthen the company's competitive position.

Многокритериальное моделирование процессов и конструкции камеры смешения пароструйного эжектора конденсационной турбины

The paper presents recommendations on designing an efficient mixing chamber and regulating air and steam flows in the elements of a steam-jet apparatus based on the results of multi-criteria modeling of gas-dynamic pro-cesses. The paper also reveals the possibilities to provide a greater reduction in losses, air suction into the turbine and equipment repair costs compared to the cases when individual criteria for increasing the steam turbine equipment efficiency are used. The selected calculation methods, i.e. innovative (multi-criteria) and standard (standard), have been analyzed comparatively. As a result of the methods evaluation, the authors se-lected the following indicators: increased energy efficiency of the turbine due to the prevention of air suction in the turbine seals; increased efficiency of condensing turbines; reduced repair and maintenance costs for the turbine and ejector due to the ejector mixing chamber cross-sectional area optimization. Based on the comparison, the best results were shown with the multi-criteria modeling according to the indicated parameters, the coefficients of the flow rate, working steam consumption, size reduction and increase in service life from 20 to 40 years. The innovative method requires a larger number of optimality criteria and the regulation of process pa-rameters and design geometry based on direct and feedback multi-criteria models. Using multi-criteria modeling, the authors determined the necessary composition of optimization parameters, i.e. the flow area of the designed mixing chamber, steam flow rate and thermodynamic flow parameters, as well as suction pressure.

The effect of repair costs on the profitability of a ureteroscopy program.

Ureteroscopy (URS) is a common treatment for patients with stone disease. One of the disadvantages of this approach is the great capital expense associated with the purchase and repair of endoscopic equipment. In some cases, these costs can outpace revenues and lead to an unprofitable and unsustainable enterprise. We sought to characterize the profitability of our URS program when accounting for endoscope maintenance and repair costs. We identified all URS cases performed at a single hospital during fiscal year 2013 (FY2013). Charges, collection rates, and fixed and variable costs including annual equipment repair costs were obtained. The net margin and break-even point of URS were derived on a per-case basis. For 190 cases performed in FY2013, total endoscope repair costs totaled $115,000, resulting in an average repair cost of $605 per case. The vast majority of cases (94.2%) were conducted in the outpatient setting, which generated a net margin of $659 per case, while inpatient cases yielded a net loss of $455. URS was ultimately associated with a net positive margin approaching $600 per case. On break-even analysis, URS remained profitable until repair costs reached $1200 per case. Based on these findings, an established URS program can sustain profitability even with large equipment repair costs. Nonetheless, our findings serve to emphasize the importance of controlling costs, particularly in the current setting of decreasing reimbursement. A multifaceted approach, based on improving endoscope durability and exploring digital and disposable platforms, will be critical in maintaining the sustainability of URS.

Using the Cumulative Cost Model to Forecast Equipment Repair Costs: Two Different Methodologies

Professionals in the construction industry must be able to accurately forecast costs. Doing so not only helps assure reasonable profits for companies, but it can also help ensure that projects are delivered within budget for clients. Forecasting of equipment repair costs is one element of the larger problem of predicting overall costs. The cumulative cost model can provide construction engineers with a valuable tool for better understanding the nature of repair costs as they relate to production fleets. Data that are being collected (or that could be collected) can assist in the determination of the rate of accumulation of repair costs for a machine for a given period of use or the estimation of fleet repair budgets for a job or period. There are two different methodologies for constructing the repair cost portion of the cumulative cost model: life-to-date (LTD) repair costs and the period-cost-based (PCB) model. This paper will provide the steps and background for each of these two methodologies and compare them using a practical example.