| 摘要 |
A filtering apparatus for filtering a fluid comprises two coaxial walls which are provided with openings for the radially-outward passage of the fluid to be filtered, granular filtering material being disposed between the walls. The fluid to be filtered is fed into the space bounded by the inner wall and the filtered fluid is abstracted from an annular chamber disposed about the outer wall. The inner wall is formed from a series of annular inclined vanes. A rotary shaft disposed coaxially within the inner wall carries blades which project between the vanes. The blades scrape deposited matter from the vanes and also scrape the radially innermost parts of the granular filter material from between the vanes. In accordance with the method of the invention, the filter material is emptied periodically from between the walls and this emptied material and the material removed by the blades is carried to a treating station for regeneration and re-cycling to the upper end of the space between the walls. During emptying, a flow of air is passed in counter-current to the normal direction of flow through the filter material to prevent unfiltered fluid from reaching the annular chamber.
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