Résumé
Objective To develop a N95 filter device for medical gas terminal to remove bacteria,viruses,particles and impurities from medical gas so as to purify medical gas to sterile grade.Methos The device was composed of a filter element and a shell,and the two parts were gifted with cylindrical shape to enlarge filtration area and reduce airflow resistance.The filter element had its length being 110 mm and diameter being 40 mm,and was composed of a tubular plastic frame and high-performance N95 filter cotton with high filtration rate.The top of the filter element was fixed to the inlet end of the device,and the bottom was fastened to the outlet end by splicing.The device with a total length of 150 mm had its shell and joint made of plastics,and was 110-mm long at the inlet end and 60-mm long at the outlet end.The outside diameter of the device was 60 mm,the connection thread at the middle of the device was 20-mm long,and the cones at the two ends had a 30-mm diameter.The joints at the ends had their sizes being 5 mm according to industrial standard,which were used to connect the device with the oxygen tube.Results The device had the filtration rate being higher than 99.9％ for both particle filtration efficiency and bacterial filtration efficiency,and the desired requirements were met.Conclusion The device gains advantages when filtering bacteria,virus and particles,and thus is worthy promoting clinically.