| 摘要 |
PURPOSE:To prevent the malfunction by outside inflow pulsating flow, by equipping the filter for pulsating flow component removing at before and after pulsating flow detector in forced drainage used for electric corrosion protection etc. of underground tube. CONSTITUTION:The active filter 13 decreasing the low region component and 360Hz component, is provided between the pulsating flow detector 8 and ripple voltage detecting point and forced drainage is made. |
