| 摘要 |
<p>[Abstract] [Object] It is an object of the present invention to provide a filtering apparatus capable of efficiently filtering a large volume of to-be filtered water, in which its filtering material is less prone to be clogged, and even if the filtering material is clogged, it is possible to wash the filtering material. [Solving Means] An upward-type filtering apparatus (1) includes a pressure container (2) and a filtering material (3) made of gravels, filtering sands or particles. The filtering material (3) includes a filtering portion (9) having a plurality of layers which are laminated on one another such that particle diameters thereof are gradually reduced from a lower portion to an upper portion of the filtering portion, and a filtering sand flowing-out preventing portion (10) including a plurality of layers which located on the filtering portion and which are laminated on one another on the filtering portions (9) such that particle diameters thereof are gradually increased from the lower portion to the upper portion of the filtering sand flowing-out preventing portion. The filtering material (3) is charged into the pressure container (2) up to a ceiling thereof, or the filtering material (3) is forcibly pressed down by a retainer member (26) or a weight from above so as to suppress a case where the filtering material (3) floats up. Raw water is sent from a lower portion of the pressure container (2) under pressure of 0.05 MPa or higher.</p> |
