Design and development of vacuum pumping and liquid injection system

The vacuum pumping and liquid injection system is designed to meet the requirement of liquid automatic injection in a closed chamber. It is made up of vacuum pumping subsystem, liquid injection subsystem and control subsystem. The whole system has a high quality in vacuum pumping and liquid injection in a closed chamber. By using hardware filtering and the flow signal processing method based on pulse duty cycle and duration comparison, the injected liquid volume can be measured accurately in various strong interference environments. In order to solve the problem of injection pressure cannot be exactly controlled sometime, the method of pressure feedback control based on PID algorithm is developed. Finally, the quality of liquid injection is improved greatly and the requirements of injection are met very well.