a plane view of an agitator comprising a disc rotator, agitating vanes and rollers, and an elevational sectional view taken along the line A--A of FIG. 8A, respectively; FIGS. 9A and 9B are a plane view of an agitator provided with a washing rod vertically formed on the center of the disc rotator shown in FIGS. 8, and an elevational sectional view taken along the line B--B of FIG. 9A, respectively