Research On Hybrid Overwinding Protection System For Large Tonnage Hoisting System In Deep Wells

Overwinding protection device plays a crucial role in the safe operation of mine hoisting system.Especially,with the development of mineral resources mining gradually to the deep,the reliable operation of ultra-deep mine hoisting system has a stronger demand for the efficient overwinding protection system.However,the overwinding protection device commonly used at present has some shortcomings such as small braking force,low reliability and unsuitable for high-speed braking,etc.,so it is difficult to meet the actual demand of mine hoisting system,especially it can not meet the safety protection of overwinding of large tonnage hoisting system in deep Wells.As a non contact braking method,permanent magnet eddy current retarding has the advantages of no wear,no thermal decline,high reliability and stable braking.It is a potential non-contact braking technology that can be applied to the over-winding protection of large-tonnage lifting vessels in deep Wells.By means of permanent magnet eddy current retarding,the speed of the high-speed lifting vessel can be greatly reduced to prevent the serious damage of the large inertia vessel to the wellbore facilities.However,according to its principle,the permanent magnet retarding can only slow the moving parts,but cannot realize the final braking.Therefore,in order to realize effective deceleration and safe braking of high speed and large tonnage hoisting vessel,the steel belt mechanical buffer braking technology,which has the characteristics of collision avoidance,buffer and supporting tank,is introduced on this basis.Therefore,a hybrid overwinding protection system scheme based on permanent magnet eddy current retarding and mechanical buffer braking is proposed.In this paper,based on the analysis of dynamics,system structure design,the theoretical model calculation and finite element simulation analysis and experimental testing method for hybrid permanent-steel band,the mechanism of slow slow braking,braking distance parameter index quantification and optimization has carried out a systemic study of the key problem.The main research contents and specific work are as follows:1)Three mixed over-winding buffer schemes of permanent magnet hydraulic buffer braking,permanent magnet frictional buffer braking and permanent magnet-steel belt buffer braking were designed.Through qualitative and quantitative analysis and comparison,the over-winding protection system was finally designed by combining the permanent magnet eddy current retarder and the steel belt buffer braking device.2)A permanent magnet-steel belt hybrid overwinding protection system is designed.Firstly,the permanent magnet eddy current retarding device was designed according to the working condition characteristics of the deep well large-tonnage lifting system and the characteristics of Nd Fe B permanent magnet material,and the strength of its key component-beam was checked.Then,according to the design requirements of mechanical over-winding buffer device,the steel belt buffer device was designed,and the size of the steel belt and the buffer braking force were determined through the static analysis,the theoretical analysis of the buffer and the braking force simulation analysis.Finally,a hybrid layout strategy is adopted to integrate the designed permanent magnet and steel belt retarded braking device.3)The simulation and optimization analysis of the permanent magnet-steel strip hybrid overwinding protection system are carried out.Firstly,the optimization parameters of the permanent magnet-steel belt hybrid overwinding protection system are determined,including the over-winding buffer distance S,the cost of the buffer device P and the braking deceleration speed A,and the selection basis is expounded.Next use many physical field simulation software COMSOL to establish the finite element simulation model of hybrid permanent-steel belt retarder braking simulation analysis in the form of permanent magnet-steel belt mixed retarder braking rule,and further optimize the retarder braking rule research and analysis,quantitative mixing parameters indexes,to determine the optimal mixing device;Finally,the overwinding protection system under actual working conditions is simulated and analyzed.The simulation results show that the designed system can meet the safety braking requirements of the lifting vessel with a total load of 100 t and a lifting speed of 20m/s.4)The permanent magnet-steel belt hybrid overwinding protection system is experimentally studied.Firstly,an experimental platform of PMM-steel belt hybrid slow braking was built,and the experimental data acquisition system was designed.Then the braking distance optimization experiment was carried out based on the slow braking experimental platform,and the collected experimental data were processed and analyzed by numerical calculation method.Finally,the experimental results were analyzed and compared with the simulation results to find out the braking law of the mixed retarder of the permanent magnet and the steel belt.The results show that the longer the mixing distance of the permanent magnet and the steel belt is,the shorter the braking distance of the mixed retarder is.The more the number of retarded permanent magnets,the shorter the braking distance of the mixed retarded permanent magnet and steel belt.There are 111 figures,23 tables and 90 references in this paper.