Research And Development Of The Autoclave Control System On Safety Disposal Of Livestock

This dissertation is addressed to an autoclave control system of safety disposal of livestock, which is the practical part of our scientific research project.This dissertation includes the presentation of the status quo of livestock decontamination in China, the comparison of prevailing techniques on livestock disposal in China, the advantage of autoclave system, the state of the art of the autoclave system and the operation practical significance of this project.The paper analyzes the technical process, the system composition of the livestock decontamination, the systematic function and operating principle of the autoclave control system. Based on the work characteristics of the pressure vessel and the mechanical characteristics of the door, the software and the hardware interlocks become necessary for safety purpose, which is realized by PLC in the electrical design of system. The PLC programming uses the ladder diagram and applies PID algorithm to control the temperature in the vessel. The developed system has the following featured:Remote monitoring is available. The system communicates with the central surveillance room through RS-485, providing the running status, data and other information, which is also able to receive, executive and modify the operating instructions. The whole processing flow of the livestock decontamination system is full automatic including charging, proceeding, pulverizing, packing, etc.Operating scheme is flexible. Manual / automatic mode switching is convenient. The whole system proceeds automatically in Automatic mode, which includes six phases such as pre-vacuum process, heat process, vent1 process, post-vacuum process, soak process and vent2 process. The tank door will be opened automatically after all processes are done and intelligence trailer tractor will be informed to transport the remnants.Safety mechanisms and malfunction diagnoses. The autoclave vessel is pressure vessel with high danger coefficient. The safety and indemnification mechanisms of the control system are required, which will provide the monitoring of autoclave vessel and automatically dealing with common malfunctions. Once the emergency occurs, system can stop and resume the pressure in the vessel.The system provides abundant graphic controlling touch-screens with convenient parameters inputting and friendly interfaces. The graphic control terminal communicates with PLC through serial communication. The program in terminal is designed with functions such as operation status showing of equipments in product line, temperature trend curve showing, pressure trend curve, real time alarm of system, etc.The laboratory simulating system is developed to ensure the system reliability, which simulates the physical and mechanical characters and possible malfunctions of the autoclave vessel. Lots of tests and validation of system have been preceded before debugging on site.The last part of dissertation is the summary on the research work based on the results and prospect of project.