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

环卫材料纵横方向透水性评价装置的研制

基本信息

批准号：
05680017
负责人：
TAGAYA Hisako
金额：
$ 1.47万
依托单位：
Shiga University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

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.

注意了液体在不依赖外力的情况下径向渗透到纸、布等多孔物质中的暂态现象，并试制了电容法跟踪这种现象的测量仪。在水平相对的两个平行板电极中的一个上钻了一个小孔，通过这个小孔，液体容器连续供水。样品放在两个电极之间，并施加矩形波。从接触这里的那一刻起，电容就发生了剧烈的变化。记录了这一点，并对其渗透特性进行了分析。对于半径为5 mm的滤纸，水的瞬时渗透速度小于1 S，这是由与水接触的表面的粗糙度控制的，并且在粗糙表面中大于光滑表面。考察了供水孔直径与穿透速度的关系，确定3 mm为适宜直径。孔的直径越大，瞬变阶段的侵彻速度越快，达到平衡侵彻的时间越早。对于液滴在纸上的径向穿透，渗透率A与时间t的关系为A=Kt^n，其中K是与纸和液体的性质有关的常数。因此，用两种对数标度绘制A和t关系的实验结果时，发现它们是由三条不同梯度n的直线组成的：首先，在S小于0.5时的过渡周期内，检测到约n=1.8，这比迄今发表的稳态数值要大得多。随后，出现了n=0.9的区域，然后是n=0.3的区域。已知，n和n的持续时间成为决定样品渗透特性的指标。