This paper analyses a control strategy applicable in heaVy-duty hydraulic Systems,namely, the introduction of a servovalve to achieve smoother operation of direCtional-control valves that serve also as flow-control va...This paper analyses a control strategy applicable in heaVy-duty hydraulic Systems,namely, the introduction of a servovalve to achieve smoother operation of direCtional-control valves that serve also as flow-control valves over two fanges of operating conditions. A mathematical model of the dynamics of the System is etallished and design criteria are obtained from a linearised form of that model. The influence of variations in tile axial force on the spool of the main valve is investigated, and the use of the resultS in the design of systems of the proposed kind is discussed.展开更多
Based on the features and requirements of gas drainage system, an optimized explosion resistance technology is done after a comprehensive analysis and research about the triple IR （Infrared Ray） flame detection tech...Based on the features and requirements of gas drainage system, an optimized explosion resistance technology is done after a comprehensive analysis and research about the triple IR （Infrared Ray） flame detection technology, explosion resistance valve technology and explosion resistance control technology. An intelligent PLC （Programmable Logic Controller） resistance control system is designed which can cut offthe gas branch quickly and accurately, and the controller have automatic pressure maintaining function, valve rotation limit function, remote and local control interlock function. The reliability and rationality of explosion resistance technology is verified by gas pipeline explosion propagation and resistance simulation test. Overall response time of explosion resistance system is less than 100ms, and the spread of fire in gas pipeline can be prevented effectively.展开更多
文摘This paper analyses a control strategy applicable in heaVy-duty hydraulic Systems,namely, the introduction of a servovalve to achieve smoother operation of direCtional-control valves that serve also as flow-control valves over two fanges of operating conditions. A mathematical model of the dynamics of the System is etallished and design criteria are obtained from a linearised form of that model. The influence of variations in tile axial force on the spool of the main valve is investigated, and the use of the resultS in the design of systems of the proposed kind is discussed.
文摘Based on the features and requirements of gas drainage system, an optimized explosion resistance technology is done after a comprehensive analysis and research about the triple IR （Infrared Ray） flame detection technology, explosion resistance valve technology and explosion resistance control technology. An intelligent PLC （Programmable Logic Controller） resistance control system is designed which can cut offthe gas branch quickly and accurately, and the controller have automatic pressure maintaining function, valve rotation limit function, remote and local control interlock function. The reliability and rationality of explosion resistance technology is verified by gas pipeline explosion propagation and resistance simulation test. Overall response time of explosion resistance system is less than 100ms, and the spread of fire in gas pipeline can be prevented effectively.
