Design Of Vacuum Sewage Control System And Study On Pipeline Water Blocking Prevention Technology

In this paper, based on the vacuum sewage system developed by the technical team of Huazhong University of Science and technology and project of East Lake vacuum toilet, the work of vacuum sewage system, control theory and control requirements were discussed. The vacuum station and the terminal control circuit were optimized and improved respectively. Through the introduction of industrial programmable control unit (PLC) to replace the existing relay control circuit, the vacuum sewage control system were more stable and easier maintenance. Water blocking may occur during long-range transport by vacuum system, so pipeline water blocking prevention technology were designed preliminarily.Control apparatus of vacuum sewage system mainly consists of two parts: the vacuum station control circuit and user terminal control circuit, which was divided into two kinds of outdoor and indoor control. With the experience gained during the use of East Lake vacuum toilet, original vacuum station control circuits have been streamlined and optimized, making it more stable and smart. Terminal circuit of outdoor and indoor vacuum system were designed. Automatic flushing of vacuum toliet was achieved by using infrared sensors and the experiment proved its feasibility.PLC control of vacuum station optimized control circuit was discussed through the use of Omron PLC models CPM2A-30CDR. External wiring and internal programming of PLC was designed. According to the characteristics of 3 terminals centralized control, Siemens CPU 222 (DC / DC / DC) with 8 input and 6 output was selected to control the system. Only a corresponding increase in PLC control units can be satisfied when the number of terminals increases.During long-range transport by vacuum sewage system, water blocking may easily occur in the bending part of the pipeline because of the long length of the pipe network. In order to solve this problem, system structure, control theory and control methods of vacuum pipeline water blocking prevention technology was discussed.