Research On The Air-tightness Quality Testing Device Of Metal-PE Reduced-diameter Elbow Joints

Metal-PE variable diameter elbow joints are widely used in urban natural gas supply pipeline networks.As urban environmental protection requirements continue to increase,the demand for natural gas is increasing,and the amount of special curved joints is also increasing.In order to avoid explosions,fires,and even accidents involving personal safety due to natural gas leakage caused by the quality of the bent pipe joints,higher requirements have been placed on the airtight quality inspection of the elbow joints.Pay more attention to the quality inspection of the air tightness of its products.Due to the combination of material and structure of metal-PE variable diameter elbow joints,manufacturers are no longer satisfied with the traditional manual-dependent complex detection methods.It is urgent to study a method that can meet the requirements of quality inspection,batch production and operation.Simple and automated quality inspection device.Based on the full investigation and the actual situation of the manufacturer,this paper studies the research status of the air tightness detection technology of the elbow joint at home and abroad,and elaborates the principle of several commonly used air tightness detection methods,and proposes the flexibility.The airbag seal is combined with modern image processing technology to improve the airtight quality inspection scheme of the pipe joint of the traditional bubble method.The hardware design part of the system and the bubble image processing part were completed successively,and the design and device fabrication of the principle machine were carried out.The hardware part of the device mainly includes flexible airbag seal design,pneumatic circuit design and circuit design.The flexible airbag seal design uses rubber airbag to seal the pipeline,and the feasibility is verified from theory and simulation.The airway design is mainly airbag charging.Ventilation and charge and discharge design of the part to be tested;circuit design mainly includes power supply circuit,single-chip control,serial communication,etc.At the same time,the device selection of the camera and lifting platform,and the completion of the corresponding experimental platform.In the image processing part,the principle of various methods in the preprocessing process and the actual effects after processing are first introduced and compared.The preprocessing methods and processes suitable for this paper are selected.For the detection of motion bubbles,an improved particle swarm optimization algorithm is proposed.The threshold selection method of the variance method effectively improves the phenomenon that the target segmentation contour is incomplete.The improved threshold selection method is applied to the three-frame difference moving target detection algorithm to realize the bubble recognition and detection in the pipeline leakage process.Design the host computer with Matlab to realize the connection between the MCU and the host computer,research the image processing algorithm,and display the processed result.This paper has completed the construction and debugging of the principle inachine for air tightness detection and carried out verification test in the experimental environment.The analysis of the experimental results shows that the principle of' the paper is correct,the method is feasible,and the device performance meets the requirements of the design index,which is practical and has certain value of promotion and application.