Study On Key Technology Of Anti-impact First Rope Rapid Replacement Based On Energy Conversion

With the mining quantity of coal resources is increasing and the excavating depth of mines is increasing, the shaft hoist system, which known as the throat of underground to ground transportation, is developing to be much larger, safer and more efficient constantly.In recent years, with the continuous appearance of large mines and increasing lifting height and weight, the first wire rope replacement of multi-rope friction hoist has becomed more and more difficult.The existing methods and equipments of rope replacement are increasingly unable to meet the requirements of mines' safe production; in addition, foreign wire rope-replacing equipment is expensive and has not been applied in our country.Therefore, it is important to study a multi-rope friction hoist wire rope replacing equipment with independent intellectual property rights, which is safe,efficient and suitable for working condition with great lifting quantity and deeper mines. Study on this topic carrying out successfully under the fundings of international cooperation projects “"tudy on mine hoisting system key technology and equipment for safe operation" (ID: 2011DFA72120) as well as the 2011 Shanxi University Innovation team.Aimed at the problems that the existing methods and equipments of rope replacement has, and on the basis of full analysis of multi-rope friction hoist's operating principles and features, it studied the technology of anti-impact first rope rapid replacement which is based on energy conversion.First, the paper analyzed the additional torsional by using combined statics equation load, which caused by incorrect methods;second, studied the anti-impact rope-sending problem based on the vibration mathematical model, then, studied the key technology of turning gravitational potential energy into hydraulic energy with less fever and emulated the thermal performance of the hydraulic system based on the lumped heat capacity method.Those studies provided important technical support for developing and designing the anti-impact rope-replacing equipment based on energy conversion.In this paper, additional torsional load caused by the parallel rope replacing method was analyzed by using combined statics equation, which is bad for wire rope operation, the"old and new ropes series connection" rope replacment method which can make rope rotate freely and release stress was proposed.Based on analysis of the impact and heat problem appeared in rope-giving process of the pressing rope replacement, the key technology of anti-impact rope replacement was proposed which using gravitational potential energy to do work for energy conversion and proportional flow control valve to make rope-giving oil cylinder start and stop flexibly.The double four-bar linkage rope-clamping mechanism and the wedge locking mechanism of rope anti-running equipment were simulated.The rope clamping force intensified by the double four-bar linkage mechanism increases with the increasing hydraulic system pressure, the rope clamping force is proportional to the cylinder pressure.However, the clamping force reduces drastically when the pressure ratio of wire rope to friction pads reaches the material limit.Self-locking phenomenon generated between rope and the wedge locking mechanism that means the locking force between the locking wedge and wire rope is in proportion to the weight of the wire rope, and ultimately achieve the purpose of locking the rope.With the increase of the initial velocity of dynamic arresting, wedge locking mechanism need to overcome the increasing energy, rope's accelerating time will also increase, rope's maximum speed increase and decelerating time to steady-state speed will increase, leading to reduce the reliability of dynamic rapid arrestment of wedge locking mechanism,and the action threshold of rope anti-slipping equipment should be setted within the range of practical application and to ensure compliance with safety.The vibration mathematics models of rope-sending process were established and analyzed.The fundamental period mathematics model(?) of the rope-replacing system was brought forward.The paper proposed a key anti-impact technology that the trapezoidal accelerating curve is the best one for sending rope, the variable accelerating time is equal to the fundamental waves' vibratory period, and the whole accelerating time was equal to its integer multiples.In addition, mechanical-hydraulic co-simulation between AMESim and ADAMS was used to analyzed its effectiveness.Using lumped parameter model, the RC network heat transfer model of hydraulic system which is based on the lumped heat capacity method was established in clamping and sending rope working conditions.The hydraulic system was divided into 13 mobile nodes and 5 heat transfer surface nodes.Then 18 first-order ordinary differential equations were set up, and the thermal resistances among nodes or between nodes and environment were defined in combination with the operating conditions of rope-replacing equipment.Based on the MATLAB software, the hydraulic system's heat balance was simulated at the working conditions that the rope-replacing equipment clamps and sends rope.The main heating of hydraulic system comes from the work to overcome wire rope gravitational potential energy.The temperature of thermal equilibrium of proportional flow control valve node is higher than the fuel tank's and proportional flow control valve's work is the main heat source of the entire hydraulic system, which could easily lead to heat accumulation in the system.After setting the simulation environment temperature and let the hydraulic system run 50 minutes, the oil temperature of fuel tank tended to balance, and the maximum temperature in balance was within the hydraulic system allowable operating range, the whole system run smoothly.In conclusion, this study provides the theoretical support to the development of efficient, secures multi-rope friction hoist wire rope-replacing equipment and has great significance in improving the security of hoist rope replacing.The anti-impact hoist wire rope-replacing equipment based on energy conversion has been applied in industrial field, solved system's heating problem,prevented the impact during the precess of rope-replacing and avoid the security risks caused by heating and impact.