| 摘要 |
PURPOSE:To prevent the clogging of a pipe and to simplify the dirt disposal of a perforated plate by forming nonwoven fabric in a shape similar to and a size a little larger than the perforated plate and putting back cover bodies having plural perforations on the back surface of a face cover body having plural perforations leaving an appropriate space to form a perforated plate housing part in the shape of a bag. CONSTITUTION:A perforated plate is inserted in perforated plate housing parts 12, 13 constituted of a face cover body 1, a back cover body 4 and a back cover body 6 from openings 14, 15. After the perforated plate is packed with the face cover body 1 and the back cover bodies 4, 6, it is mounted on a perforated plate receiving ring to use it with the face cover body 1 turned upwards. Waste water is passed through perforations 3 and a mesh of nonwoven fabric of the face cover body 1, next through a water passing holes of the perforated late, and further through the perforations 5, 7 and a mesh of nonwoven fabric of the back cover bodies 4, 6 to be discharged. Since the cover bodies 1, 4, 6 consist of nonwoven fabric, dirt gets caught in the fiber of the nonwoven fabric. When the perforated plate is removed from the openings 14, 15, the dirt is disposed together with the filter. |
