| 摘要 |
<p>PURPOSE:To lower production cost, by cutting a triangular member along lines crossing both sides forming the right angle thereof at right angles through points, each of which provides a distance equal to the length of the median passing the right angle apex from said apex, to form a base member which is, in turn, used as a filter bed assembling member. CONSTITUTION:A plate like filter bed material having an appropriate plane shape or a block like one equipped with water passing gaps is cut into a right- angled equilateral triangular shape to form an element 1. The element 1 or an element 2 having a size twice that of the element 1 is appropriately combined with the element 1 to obtain a base member 3 having a right-angled equilateral triangular shape. When the base member 3 is cut along lines y1, y2 crossing both sides ab, ac forming the right angle apex (a) of DELTAabc at right angles through points (e), (f) which are present on the sides ab, ac forming the right angle of DELTAabc and provides distances ae, af, which are equal to the length of the median passing said apex (a), from said right angle apex (a), a filter bed assembling member 5 forming the shape of a pentagon aeghf is formed.</p> |
