Study On Structure And Plastic Molding Of Positive Pressure Respiratory Protective Mask

The outbreak of the COVID-19 epidemic has brought a huge threat to people’s life safety.The biggest characteristic of COVID-19 is its strong transmissibility.As the direct contact of the virus,medical staff wear heavy protective equipment during work,which leads to low work efficiency.Moreover,the existing respiratory protective equipment has obstacles in communication with the outside world when wearing it.Because of various reasons such as the protective equipment is not replaced in time after wearing for a long time,medical staff will carry and infect the virus.In view of this phenomenon,we take the positive pressure respirator as the research object,focus on the analysis of the mask material and the mask forming characteristics,analyze the material characteristics through the combination of theoretical analysis,numerical modeling and experimental verification,explore the influence of the changes of parameters such as temperature and pressure on the forming process,improve the quality of the mask,and realize the lightweight of the mask under the premise of effective sealing visualization and barrier-free communication with the outside world.First,on the premise of meeting the human tidal volume and reducing CO₂retention,the face mask is modeled;The basic characteristics of mask materials are compared and analyzed;According to the shape characteristics of the mask,the blister forming method is selected,and the blister forming process parameters are analyzed.Based on these preliminary preparations,a theoretical basis is provided for the subsequent numerical simulation.Secondly,based on the fluid structure coupling method,Fluent and the static structure module are built together to simulate the process of the mask deformation caused by the impact of the airflow in the mask.By changing the intake air flow and ambient temperature,the deformation of masks made of different materials is explored.Combined with the basic properties of materials,the material with the smallest deformation is selected as the material for processing the mask.Then,based on the optimal materials,Polyflow finite element analysis software is used to simulate the process of mask blister molding.By changing the temperature and pressure process parameters,observe the mask molding depth,thickness uniformity,area elongation and other indicators,find out the molding rule and the process parameters with the best molding quality.At the same time,analyze the impact of different initial plate thicknesses on the mask molding,and select the appropriate plate thickness.Finally,the forming process of the face shield is analyzed by comparing the measured thickness of the real object with the simulated thickness data;Trim the shaped mask to connect with the pipeline and apron,carry out wearing experiments,and verify the visibility of the mask and its ability to communicate with the outside world;The air pressure sensor is used to measure the pressure change during air supply in the mask,verify the continuous positive pressure in the mask,and ensure the safety in the mask.