| 摘要 |
PURPOSE:To remove adverse effect due to high conc. brine, in washing the filter apparatus having a packed bed comprising a particulate filter agent of a seawater desalting process, by substituting residual seawater with air or fresh water before washing the suspended substance of the packed bed with fresh water. CONSTITUTION:Seawater is allowed to flow in from a seawater inflow pipe 5 and sent to a reverse osmosis membrane through a valve 11, a filter tower 1 and a valve 12. When a suspended substance is caught by a filter packed bed and pressure loss increases, the valves 11, 12 are closed and valves 13, 14 are subsequently opened and air is flowed in from an air inflow pipe 6 to discharge seawater from a discharge pipe 9. The valve 14 is opened and the valve 13 is closed while a valve 15 is opened to allow fresh water to flow in from a fresh water inflow pipe 7 and, subsequently, the valve 14, 15 are closed and valves 13, 16 are opened to allow air to flow in from the air inflow pipe 6. Next, the valves 13, 16 are closed and valves 17, 18 are opened to allow air to flow in and, subsequently, the valves 17, 18 are closed and valves 19, 20 are opened to allow fresh water to flow in and the filter packed bed is expanded to perform backwashing.
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