Development of Apparatus for Evaluating Water Penetration in Vertical and Horizontal Directions of Sanitation Materials

注意到液体在不依靠外力的情况下沿径向渗透到纸、布等多孔物质中的瞬时现象，并试制了电容法跟踪渗透的测量仪。在两个平行板电极中的一个上钻一个小孔，通过它，水从液体容器中连续地供给。将样品置于两个电极之间，并施加矩形波。从接触到这里的那一刻起，电容急剧变化。这被记录下来，并分析了渗透特性。滤纸（5mm半径）的水的瞬时渗透速度小于1s，这取决于水接触表面的粗糙度，粗糙表面的水渗透速度大于光滑表面的水渗透速度。研究了供水孔孔径与贯入速度的关系，确定了3mm为适宜的供水孔孔径。孔径越大，过渡阶段的侵彻速度越快，达到平衡侵彻量的时间越早。对于液滴在纸上的径向穿透，穿透A与时间t的关系由A=Kt^n给出，其中K是与纸和液体的性质有关的常数。因此，当用两种对数标度绘制A与t关系的实验结果时，发现它们由三条梯度n不同的直线组成。首先，在短于0.5 s的瞬态周期内，检测到约n=1.8，这比迄今为止公布的稳态值大得多。然后是n=0.9的区域，接着是n=0.3的区域。已知n及其持续时间是决定试样侵彻特性的指标。

Attention was paid to the trasient phenomena of liquid penetration in radial direction into porous substances like paper and cloth without depending on external force, and the measuring instrument of tracking this by electric capacitance method was made for trial. On one of two parallel plate electrodes which were set horizontally facing each other, a small hole was drilled, and through it, water was supplied continuously from a liquid vessl. A sample was put between both electrodes, and rectangular waves were applied. From the moment of coming in contact here, the electric capacitance changed sharply. This was recorded, and the penetration characteristics were analyzed. The transient penetration speed of water shorter than 1 s for filter paper (5mm radius) is controlled by the roughness of the surface with which water comes in contact, and it is larger in rough surfaces than in smooth surfaces. The relation of the diameter of water supply holes with penetration speed examined, and as the suitable diameter, 3mm was decided. As the diameter of the holes was larger, the penetration speed in transient period was higher, and the equilibrium penetration quantity was attained earlier. For the radial penetration of a liquid drop on paper, the relation of the penetration A with time t is given by A=Kt^n, where K is a constant related to the properties of paper and liquid. Thereuopn, when the experimental results on the relation of A and t were plotted by both logarithmic scale, it was found that those consisted of three straight lines with different gradient n. First, in the transient period of shorter than 0.5 s, about n=1.8 was detected and it is considerably larger value than the steady state which was published so far. Subsequently, there was the region of n=0.9, and the region of n=0.3 followed. It was known that n and its duration become the indices for determining the penetration characteristics of samples.