Research On Cleaning Process Of Aircraft Filter And Equipment Development

At present,most domestic processes for cleaning aircraft filter cores use manual or semi-automatic immersion ultrasonic cleaning,which has problems of low automation,poor cleaning effect,low efficiency and high cleaning cost.In order to solve the above problems in aircraft filter cleaning,this paper studies the ultrasonic cleaning technology of various aircraft filters.Through the research on the ultrasonic cleaning mechanism of aircraft filter and the development of special cleaning equipment,the developed aircraft filter ultrasonic cleaning machine meets the filter cleaning process requirements and removes oil stains and particles on the filter element.The washing machine can also be widely used for the cleaning of conventional filter elements,and can also be applied to the cleaning of common parts.The main research contents of this paper are as follows:The cleaning process of the aircraft filter element was improved,and a vacuum ultrasonic rotary cleaning and vacuum drying aircraft filter cleaning process using a hydrocarbon solvent as a cleaning agent was designed.The cleaning process is mainly divided into:vacuum low frequency ultrasonic rough washing,vacuum high frequency ultrasonic fine washing,low vacuum gas phase cleaning,high vacuum drying four steps,among which vacuum ultrasonic cleaning technology and high vacuum drying technology are mainly used.The cleaning mechanism of ultrasonic waves was studied.According to the motion law of cavitation bubbles generated by ultrasonic cavitation effect,Matlab was used to solve the motion equation of cavitation bubble wall under multi-parameters.The frequency and sound pressure amplitude of ultrasonic wave were analyzed.The effects of ultrasonic frequency,sound pressure amplitude,initial bubble size and ambient pressure on cavitation bubbles were analyzed.According to the calculation results,28 kHz and 40 kHz was selected as the frequency of ultrasonic coarse-washing large particle pollutants and fine-washing small particle pollutants,which is different from the single-frequency ultrasonic wave used in the traditional cleaning process;the vacuum ultrasonic cleaning process was established,and the ultrasonic sound was selected.The pressure amplitude is 1.9×10~5 Pa.According to the parameters of the aircraft filter and the requirements of the cleaning process,the mechanical structure of the aircraft filter cleaning equipment is designed.The main design contents are:Structural design,temperature control design and strength check of the cleaning tank and the drying tank;movement path design,structural design and strength check of the manipulator.The piping design and control system design of the cleaning machine is based on the cleaning process and mechanical structure of the aircraft filter.The pipeline design includes:circulation of cleaning fluid,filtration and distillation,design of cooling pipeline,piping design of vacuum system,design of heating system,etc.A set of automatic control system for vacuum cleaning process was designed in the control system,which can realize the automatic cleaning of the filter element and the monitoring of the status of each part during the cleaning process.The filter cleaning process designed by this subject and the developed filter cleaning machine can meet the requirements of aircraft filter cleaning.The cleaning machine is applied to actual production,which shortens the cleaning time of the aircraft filter by 87%and the cleaning effect by 30 times.The research on the filter cleaning process and the design of the cleaning equipment can be extended to the cleaning of other parts.