| 摘要 |
PURPOSE:To directly detect the generation of cavitation by providing a pressure difference detector detecting the pressure difference between the inlet side and outlet side of a diffuser, a pressure difference variation detecting circuit, and a recirculation flow detector. CONSTITUTION:When cavitation occurs in a jet pump 109, the efficiency is deteriorated, the flow in a diffuser 110 is reduced, and the pressure difference between pressures at the inlet side and outlet side is changed. This pressure difference is detected by a pressure difference detector 123 and sent to a pressure difference variation detecting circuit 126 through a calculating circuit 125 of extraction of the square root, and a signal is sent to an interlock circuit 127 when the pressure difference is changed. When the recirculation flow is constant, the interlock circuit 127 sends a signal to an alarm unit 128, thus causing it to generate an alarm that cavitation has occurred. When the recirculation flow is changed, the pressure difference in the diffuser 110 is changed and the recirculation flow signal is also changed, thereby no signal is sent out from this interlock circuit 127 and no error operation is generated. |
