Design Of Automatic Marking Machine And Analysis Of Heating Uniformity

With the continuous development of China’s road construction and the continuous improvement of labor costs,improving the efficiency of road marking has become one of the problems in urgent need of solving in our country’s road construction.But at present,the automation level of road marking construction machinery in our country is rather low,and road marking is mainly carried out through hand-pushing marking machine for proficiency of workers made more stringent requirements which has low efficiency.To mitigate the related problems,it is very necessary to improve the automation and intelligence of the road marking machine.The main results are summarized as following:Firstly,this paper introduces the overall structure and design methods of the road automatic marking machine.The road automatic marking machine is mainly composed of five systems such as hot melt kettle system,material storage and material transmission system,walking mechanism,glass bead spreading system and electrical control system.The design parameters of each system are determined from the overall parameters of the road automatic marking machine.We can calculate the relevant parameters of the components by the design parameters’ selection of components.Secondly,the heating uniformity of the coating was studied by using Fluent software which is based on turbulence model and multiple reference system method.The flow field and concentration field of screw belt stirring mechanism,frame stirring mechanism and universal stirring mechanism are simulated respectively and the effects of different mechanisms on the paint flow field and tracer concentration distribution in the hot melt kettle are analyzed.The results show that the stirring mechanism is directly related to the velocity field and tracer concentration field of the coating.Compared with the other two mixing mechanisms,the screw ribbon mixing mechanism has the largest high-speed flow area formed by mixing in the coating,and the mixing time of the tracer with the coating in the hot-melt kettle is the shortest and more evenly distributed,which is conducive to the heat transfer of the coating and make the heating of the coating more uniform.Thirdly,the structural parameters and motion parameters of the screw ribbon stirring mechanism are simulated in the flow field of molten coating and the mixing field of molten coating and tracer in the hot-melt kettle by fluent simulation software.The results show that the smaller the pitch of the screw ribbon stirring mechanism,the higher the speed of the rotating speed and the greater the flow field speed of the coating,the more likely it forms a large circulating flow field in the hot-melt kettle.The shorter mixing time,the more uniform the heating of the coating.And the greater the motor power is required;The higher the installation height of the mixing mechanism is,the easier it will be to form a mixing dead zone at the bottom of the hot-melt kettle,which is not conducive to the mixed heat transfer of the coating.However,the lower the height is,and it is not conducive to the mixed heat transfer in the liquid level area of the hot-melt kettle.Through the analysis and exploration of the above contents,the improvements to structural parameters and motion parameters of the screw ribbon mixing mechanism are studied by using numerical simulation.This result can provide important reference value to improve the heating uniformity of the coating.