| 摘要 |
<p>An outer tube (16) is connected at its top end to a rain gutter and is connected at its lower end to a catchment basin which communicates with a sewer. Connected to a storage infiltration pit is the lower end of an inner tube (18) disposed with the outer peripheral edge of an upper portion thereof spaced a predetermined spacing from the inner peripheral surface of a vertical portion (16d) of the outer tube. A ring-shaped flow dividing member (24) is provided on the inner peripheral surface of the vertical portion of the outer tube at a location spaced a predetermined distance above the upper end of the inner tube. The flow dividing member comprises a ring-shaped groove (24a) which receives rain water flowing down along the inner peripheral surface of the vertical portion of the outer tube, a plurality of through holes (24b) which are formed at the bottom portion of the groove to align circumferentially with one another and serve to conduct rain water in the groove to the catchment basin, and an inner peripheral wall (24c) formed in a tapered shape so as to be reduced in diameter toward a downward direction and serving to conduct rain water, which overflows the groove, to the inner tube. Clogging of the storage infiltration pit and contamination of a storage tank caused by rain water which contains much sand and dust, is prevented, and flow of rain water can be automatically divided into the sewer and the storage infiltration pit or the storage tank depending upon intensity of rainfall, so that rain water is prevented from flowing into sewers and rivers above their flowing capacities.</p> |
