Selegej A. Substantiation of rational power-dynamic parameters for iron notch tappers

The dissertation presents new scientifically proved theoretical and experimental data necessary for accomplishing the task of determining dynamic parameters for iron notch tapping and choosing rational parameters for drilling mechanism of iron notch tapper. The solution has been found in the result of complex theoretical and scientific study of the design of iron notch tapper units. The conditions of iron notch tapping have been analyzed and the factors which fulfill basic requirements for tap-hole conduit have been defined. The strength characteristics of tap-hole clay that is used in Ukrainian and CIS enterprises have been studied and systematized. Drill rod stability in iron notch tappers has been analytically evaluated and critical axial load depending on various types of rod fastening has been calculated. Having evaluated the resistance, such factors as drill rod rotational speed and applied torsional moment have been taken into account. The range of changes in dynamic factors of drill tapping including torsional moment and axial force on a drill rod has been empirically tested. Recommendations for choosing rational parameters of drill rod support in tapper have been developed. The mathematical model describing heat transfer between taphole clay and drill rod has been worked out. As a result the required amount of cooling agent supplied to axial conduit has been determined. The effect of the tool on solidified tap hole clay while applying different modes of blast furnace iron notch tapping has been theoretically analyzed. Due to these data the required torsional moment on a drill rod while using tap hole clay with various strength characteristics has been determined. Recommendations for selecting optimal cross sections of a drill rod as well as drill piston-striker have been developed. Impact-rotation type drill bit for tapper has been designed, based on the results of studying the process of iron notch drilling. Such drill bit has been found to be more reliable in iron notch tapping and less expensive compared to the analogous. According to the analysis of taphole drill operation the optimal choice of its geometrical parameters for achieving necessary impact energy has been substantiated.