Design Of Continuous Counter-current Ultrasonic Extraction Control System

Along with the modern science and technology rapidly development and people living standard unceasing enhancement, the biological product is playing a more and more important role in people's daily life, such as daily necessities like food, health care products, cosmetics or medical drugs. The technology of bio-extraction has been a member of important research issues in the process to the research and development of biological products. The method of the extraction of effective components from the plant is mainly intermittent extraction process at home and abroad, this manufacturing technique is composed of tanks. Because of materials can't be moved, just the solvent does directional flow, the raw material and the solvent can't contact with each other sufficiently,so the process has bigger mass transfer resistance and the concentration of extracting solution with effective constituent can't form ideal gradient all the time. At present, along with the deep research of bio-extraction, a new production process has been discovered called continuous counter–current extraction. First the raw material should be steeped in preimpregnation module, secondly materials should be extruded, rubbed and mixed after having became soft, finally guide materials into countercurrent extraction device and extract the effective elements. Because of each step requires coordination and strict operation, but the relationship of each equipment is very complex, so the ordinary control system can't undertake tasks. The existing control system is only made up of field layer and control layer, effective products data can't be sent to management and only be saved to the local database.In order to improve the production efficiency and management level, realize integrated automation system that the automatic control combined with management for the process of bio-extraction, this paper take the continuouscounter-current ultrasonic extraction process as the research object, and study the hardware configuration of the control system, network configuration, CFC programming and Win CC configuration thoroughly from some aspects based on PCS7.Finally came up with fuzzy cascade control strategy and ratio control strategy. After testing, it is shown that system is stable and reliable and easy to operate, overcame the disturbance and delay effectively, have stronger ability of fault tolerance, enhanced the extraction efficiency. All of the above proved this a production and operation system with high efficiency and high flexibility, it can adapt the uncertainty of the production environment and the changing market demand.