| 摘要 |
The present invention relates to a strainer-type height-adjustable underdrain system using a porous filter media supporter in wheeler-and strainer-type underdrain systems of a gravity-type rapid filtration basin removing a suspended material during a water purifying process. The strainer type underdrain system is screw-coupled to each of injection holes defined in a top surface of an underdrain block at regular intervals, a porous filter media supporter (40) attached to the top surface of the underdrain block to support the filter media and being able to prevent the filter media from being lost and clogged is connected through a continuous thread bolt (23), so as to easily adjust a height of a strainer body (20) by operating a height-adjusting fixing nut (27), the continuous thread bolt (23), a porous filter media supporter fixing nut (24), and a fixing nut (21). Thus, a leveling error between an equalizing line (54) of a pressure compartment and a back-washing air slit (29) of a lower portion of the strainer body (20) can be adjusted to a height suitable for a back-washing design condition of the underdrain system, to thereby reduce the leveling error of the underdrain block allowing back-wash to be equally performed during back-washing of air and water. Resultantly, cleaning efficiency of a filtration sand layer and the porous filter media is improved, and filtering efficiency is improved by minimizing a dead zone through uniform distribution of the pressure compartment of the filtration basin. Further, loss and clogging of the filter media caused by abrasion or damage of air- and water-injection holes is prevented by supporting the filter media by the porous filter media supporter without a typical strainer cap. |
