| 摘要 |
A filter apparatus comprises a filter screen for filtering liquid carrying solids to remove at least some of the solids from the liquid. A nozzle is arranged adjacent the filter screen for removing solids deposited on the filter screen during a filtering operation, a variable speed drive causes relative movement between the filter screen and the nozzle such that deposited solids are removed from successive portions of said filter screen, and a control unit controls the speed of the relative movement in dependence upon the degree of blockage of the filter screen by the solids deposited on the filter screen. Throttling the discharge of the filtered liquid causes liquid to flow from the side of the filter screen remote from the nozzle back through the screen into the nozzle which is provided with an inlet having an adjustable cross-sectional area for varying the flow therethrough. A cleaning system arranged to direct clean liquid through the filter screen into the nozzle is provided for cleaning the screen should the screen become completely blocked. |
