Abstract
Self-induced vibration is possibly caused by the semi-closed pipeline combining the automatic pressure regulator with the automatic constant flow valve. Thus, a test was conducted on the site to analyze the generation of the coupled oscillation between the automatic pressure regulator and the direct-acting constant flow valve. Further, the investigation was conducted in order to show the function of the constant flow valve, obtain self-excited oscillation, and to study the control measure. Consequently, when the direct-acting constant flow valve is used near the setting flow, the working mechanism activates the valve using the pipe pressure and the large self-excited oscillation can be induced. On the other hand, when the flow is smaller than that of the setting flow of the direct-acting constant flow valve, the self-excited oscillation is not generated. Further, with regard to the measures to control self- excited oscillation, it is known that self- excited oscillation is not completely restrained by merely blunting the response sensitivity of the automatic pressure regulator.
