| 摘要 |
PURPOSE:To prevent the water stream from being obstructed on contraction by arranging the superposed edge part of a flexible sheet onto the upstream side and arranging the top side part onto the bottom surface of an underdrain and arranging the inclined side part onto the side surface of the underdrain, thus permitting the close sealing on expansion. CONSTITUTION:A valve body 1 consists of a flexible sheet, which is bent along the folding lines 6 and 7 and set along the bottom surface 8, side surface 9, and a ceiling surface 10 of the inner wall of an undedrain, setting the superposed edge part on the upstream side. A band-shaped fixing metal fitting 11 is fitted along the top side part 3 as the superposed edge part and an inclined side part 4, and these parts are fixed onto the inner wall of the underdrain by an anchor bolt 12. On expansion, the parts along the bottom surface, side surface and the ceiling expand, superposed in the longitudinal direction, while on contraction, the whole is closely attached onto the inner surface of the underdrain. |
