| Divided into the active one and passive one, the safety of coal mine vertical hoisting system is generalized including the safety reliability of all equipment components and the controlling elements, the whole system safety reliability, and the ability to prevent any abnormal factor from expanding accidents. From the perspective of dynamics, to study the equipments and the equipment designs, the control, the operation, and the maintenance of the hoisting system is a foundation for the system security improvement as well as a significant approach to dealing with the contradictory between safety and productive efficiency.The discrete multi-degree vertical friction hoisting system dynamic model is built by using the Lagrange Method where a tail rope is taken as an independent degree, and wire damping is taken into account. Based on the above, by considering the uniform quality characteristics of the rope, the model is simplified into the 5-degree tower model, 7-degree console model, and 2-degree model respectively as the bases for a further safety research. Meanwhile, the fuzzy reliability theory with the friction factor as a random variable and the additional hoisting resistance as a fuzzy variable is firstly applied into the antiskid calculation of friction hoisting. Thereby, based on the fuzzy reliability theory, a safety evaluating approach for wire antiskid is established.With the assistance of the above theoretical research, the bend track unloading process is dynamically analyzed, and the bend track and its system designing methods are given. In conjunction with the data collected at the scene of the coal unloading, the unloading time and the time forecasting techniques are studied to predict the experience formula on the unloading time prediction. Additionally, the synergies of ground and underground loading are analyzed, which has provided a theoretical basis for the reasonable design of the main shaft hoisting system. In terms of the antiskid safety, the combination of dynamics and the reliability theory is beneficial to the system security improvement and to the reliability prediction, which has been applied in the engineering practice, resulting in good results. The research shows that any tonnage skip can theoretically adopt bend track unloading ways.Concerning the safety application in the supporting process of auxiliary shaft cages, the supporting process of cages is dynamically studied by considering the pre- compressive deformation of a spring device, the flexibility of the pre-compressive device and the wire rope damping as modeling factors. The simulation results demonstrate that for the cage in the Supporting process, its largest acceleration and upgrade offset have an approximate linear relationship in a certain range; that the value of the offset should be small so as for the cage not to be lifted because of flexibility, for the wire not to loosen or slide and for the upgrade offset to be normal; and that reducing the stiffness of the Supporting Device is beneficial in reducing the biggest wallop of the device, which is useful to the equipment protection and also to the reduction of the equipment damage rate.The depth and comprehensiveness of the vertical friction hoisting system safety research are enhanced by studying the passive safety protection. Modeling and simulation results indicate that the overwind and underwind braking trips depend largely on the force size of their respective set of protective device, the force of the overwind side is larger than that of underwind and that given that the overall burden of the overwind and the underwind side protection devices as well as the height of derricks and well towers are never increased, the side should not be put into the braking protection ahead of time but both sides should enter the brake simultaneously. Because of the great uncertainty of the wedge-shaped wooden tank failure, the wedge-shaped cans and the volume protection device are unsuitable to be simultaneously installed with respect to safety.
|
PDF Full Text Request