| The belt conveyor is the core equipment of the coal mine transportation system.In order to meet the requirements of various transportation conditions,its conveyor belt is usually made of multi-section belt vulcanization.However,in actual production,the joints of the conveyor belt are prone to belt breakage failure,and even cause secondary accidents.In order to improve the quality of vulcanization and solve the problems of long heating time and uneven heating in the existing vulcanization methods,this paper proposes a method of vulcanization of tape joints based on electromagnetic induction heating.An electromagnetic induction vulcanization heating system for tape joints is established,and the key components of the heating system are studied through experiments and numerical simulations.Firstly,in order to explore the influence of external current and frequency and other electromagnetic parameters on the heating performance of the plate,the COMSOL software was used to simulate the electromagnetic thermal coupling of the heating system under different electromagnetic parameters.The study shows that when the current is controlled at 12 A and the operating frequency is controlled at about 13000 Hz,the temperature difference of the heating plate can be kept in the ideal range,which is the better value of the electromagnetic parameter.By analyzing the temperature rise curves under different working conditions,the effect of a single factor on the heating effect was obtained.After that,the orthogonal design method was used to optimize the factors that affect the heating performance.The research shows that in the designed parameter combination,the distance between the coil and the heating plate is 8 mm,the coil wire diameter is 3 mm,and the current is 12 A,the heating plate surface has better heating uniformity.Secondly,a conveyor belt joint vulcanization heating system and a temperature monitoring platform based on electromagnetic induction were built,and the heating temperature was monitored through experiments to analyze the temperature change law.The parameters such as maximum temperature unevenness,relative unevenness and average temperature of the heating plate were introduced to study the influence of different parameters on the temperature unevenness of vulcanization heating by controlling a single variable.The research shows that the closer the distance between the heating plate and the coil,the more uneven the surface temperature distribution.The current during heating should not be too strong.In order to ensure the uniformity of the vulcanization heating,try to use a coil with a larger wire diameter.Then,the conveyor belt joint was vulcanized by means of electromagnetic induction heating and electric heating.And compared the performance of the joint parts of the conveyor belt after vulcanization.The experimental results show that the performance of the conveyor belt joint compound after vulcanization by electromagnetic induction heating is better.Compared with electric heating,the adhesive strength,tensile strength,maximum breaking force and hardness of the conveyor belt core rubber vulcanized by electromagnetic induction heating were increased by 3.72%,8.44%,1.05% and 1.43%.The tensile strength,maximum breaking force and hardness of the cover rubber were increased by 5.60%,0.60% and 0.49%,respectively,and the wear was reduced by 1.25%.Finally,through experiments,the thermophysical parameters of the two conveyors belt joint compounds and the heat change during the vulcanization process were explored,and the endothermic enthalpy change of the rubber compound during the vulcanization heating process was tested.The results show that the thermal conductivity decreases first and then increases with increasing temperature,and the specific heat capacity increases with increasing temperature.The enthalpy change values of the flame retardant conveyor belt joint cover rubber and core rubber,the fire-resistant conveyor belt joint cover rubber and core rubber are 0.04 J/g,0.11 J/g,0.04 J/g(0.06 J/g),0.18 J/g?... |
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