Study On Explosion-proof And Sealing Performance Of Pipeline Inspection Robot

Pipeline plays an increasingly prominent role in production activities because of its convenience,safety and continuity.The backward and inefficient traditional maintenance measures restrict the development of the pipeline transportation industry,and the emergence of robots provides new solutions.However,the harsh working environment such as combustible gas and complex component fluid in the pipeline places high demands on the performance of the pipeline robot.Based on the application requirements and performance research,this thesis uses the combination of theoretical derivation,structural design,simulation analysis and experimental verification to study the explosion-proof and sealing performance of the pipeline robot prototype to improve the adaptability and the system reliability.Firstly,according to the environmental conditions and operation requirements,the explosion-proof grade and standard of the robot are formulated.On the basis of comparing the advantages and disadvantages of the basic explosion-proof type,static positive pressure is selected as the main explosion-proof type.The effective time of explosion protection is calculated by Fick's law of diffusion,and the theoretical working time is obtained.At the same time,combined with the explosion-proof standard GB3836,the explosion-proof housing,cable introduction device,built-in positive pressure system and scavenging pipeline are designed,and the pressure change process is analyzed to obtain the working process sequence of the built-in positive pressure system.Secondly,based on the complexity of the fluid composition,the environmental conditions and operation requirements are analyzed,and the failure criteria are clarified by analyzing the failure modes.The nonlinearity of rubber is analyzed by finite element theory,and the superelastic constitutive model is established.The Mooney-rivlin coefficient is determined,which laid a foundation for the establishment of material model in the simulation process.At the same time,the structural design of the sealing system is carried out to solve the sealing problem during the pressure change process.Afterwards,based on the design of the explosion-proof and sealing system,different packing pressure differences and different amounts of compression are critical for positive pressure holding and sealing reliability.Through the finite element method and ABAQUS software,the control variables such as pressure and compression are analyzed.The Mises stress,contact stress and shear stress of the main components of the system are analyzed from the simulation,and the air tightness and watertightness are verified.Air tightness and water tightness can meet the requirements of explosion protection and sealing,and the position where the sealing ring is prone to fatigue failure is obtained.In order to ensure the strength of the explosion-proof housing,the Mises stress,logarithmic strain and spatial displacement of the explosion-proof housing are analyzed and discussed to ensure that the material selection and structural design can meet the design requirements.Finally,the experimental system developed by LABVIEW is used to study whether the performance indicators of the prototype meet the explosion-proof and sealing performance requirements.At the same time,the effects of different variables on explosion-proof and sealing performance are studied to verify the correctness of the simulation results.According to the national explosion-proof standard,an explosionproof experimental scheme is prepared,mainly including the highest positive pressure test,leakage test and thermal test,and the shell strength,positive pressure loss condition and internal temperature rise are studied.The influence of the packing pressure difference on the gas leakage is obtained to ensure that the explosion-proof requirements are met.The sealing experiment is carried out on the control variables of the two factors for the compression amount and the rotational speed.The relationship between the compression amount and the rotational speed on the liquid leakage is obtained.By comparing and analyzing the simulation data and experimental results,the conclusions are drawn.