E: Safety Factor Module
Safety factor module is used to calculate safety indicator that shows to what a degree the belt weakened by cord cuts is able to transfer stresses that occur on the conveyor’s route in both stationary and non-stationary motion. The developed computational software uses the functions of QNK-TT program, which was created at the Institute of Mining Engineering, Wroclaw University of Technology in cooperation with the AGH University of Science and Technology in Krakow and which is aimed at determining individual stress distributions for a conveyor. It also uses the results of strength tests on belts weakened by cuts, as well as the results of FEM (Finite Element Method) simulations of the weakened areas.
Operational Belt Safety Factor (OBSF) was determined on the basis of state-of-the-art methods for calculating motion resistances and forces acting on the belt, on the basis of most recent technological advancements in steel-cord belt diagnostics, and on the basis of most up-to-date splicing improvements.
OBSF is intended for use in transportation systems comprising steel-cord belt conveyors, in which modern belt diagnostic systems are installed to allow for the processing of data on belt damage along with its spatial location.
Visualization of the monitored belt’s section; damage level is visualized in discrete, square grid, the colors of the grid’s square areas refer to average damage level, the points refer to registered maximal value in the area.
Even more precise estimation of the wear degree of steel-cord belts and their splices, or a more precise calculation of maximum forces acting on the belt, is not enough to fully describe the influence of belt operation on its condition. Apart from visual inspection, which was used for many years, such evaluation is aided by complex monitoring methods and works related to FEM-based modeling of stress distribution in the damaged belt. Analysis of standardbelt monitoring results allows to substitute the operating conditions impact indicator with a value determined through the diagnosis of the belt’s condition.
Steel-cord belt conveyor equipped with OBSF monitoring system using modern diagnostic system will allow to significantly reduce the required belt safety factor (BSF). This will also positively influence the energy-efficiency of conveyors. Such solutions are particularly important for long-range conveyors, in which the belt’s strength is usually a major factor limiting the route’s length. Hence, the technology may be particularly attractive in long-distance transportation of brown coal to power plants or stone aggregates to road or railroad loading points.
Large transportation systems, in which periodical diagnostics of belt condition is performed (or such diagnostics is considered) are considered another potential area, where OBSF calculation method might prove important. In such cases OBSF will allow for large-scale reduction of the belt’s strength and mass.