Research On The Proportional Valve With Electric-Feedback And The Principle Of Flow Amplily

This paper analyses the type, function and characteristics of usual proportional control valves and raises a new modificative version in the light of their drawback. That is, basing on the principle of flow amplification and electrical feedback and throughout calculation and analysis on flow closed loop control and pressure flow combination., determination of the minimum controlled pressure difference as well as flow controlling range and structure of main valve and research of the dynamic and static characteristic, the paper puts forward control principle of " flow- load pressure change- displacement revision" and pressure/flow double closed loop, and further expounds that using a proportional controller and a electric mechanical transducer can separately serve the control function of pressure or flow as well as flow pressure combination.Through researching proportional cartridge valve of Valvistar valve made in Sweden, the paper raises a new principle on flow control. That is, through analysis of the principle on flow control and "hydraulic transistor" , design and calculation of flow control characteristic as well as main parts in valve inner chamber, a piloted reducing valve will be installed between main valve and pilot valve. After a pressure-difference compensating reducing valve was added in the non-pressure compensating piloted reducing valve of the flow control valve in Vlalvistor valve, the calculation on control characteristic emulation and load characteristic emulation has been carried out. The result of the calculation shows that after pressure compensating reducing valve was added, the linearity of the control characteristics has been greatly improved thus eliminating influence upon outlet flow by load pressure-change of the hydraulic system and improving performance characteristics of the hydraulic component.