抄録
The usual type of pressure-reducing valve always causes offset due to its proportional control mode. The improvement of its characteristics, on which one of the authors formerly reported, is bounded within a limit, so far as the proportional control mode is adopted. For drastic improvement, the integral control mode must be adopted.
A new type of self-operated pressure regulating valve reported here has on-off integral control mode which is realized by the use of a push-pull type nozzle-flapper, restrictions and diaphragms. The controlled output pressure is almost constant within a remarkably wide range of flow rate, compared with the case controlled by the usual type of pressure-reducing ing valve. Steady state errors for the change of set point and supply pressure are also very small, and the amplitude of steady state pressure cycling is practically of negligible order. The cycling phenomena are discussed here theoretically by the descri-bing function method and the main cause of the cycling is revealed to be the friction on the valve stem, rather than the on-off character.
