Vertical agitating apparatus

A vertically agitating apparatus comprising an agitating tank having a center and having a cylindrical part with a top edge, and a conical bottom part connected to the cylindrical part along a boundary therebetween, and having an acute apex angle, a rotary shaft having an upper part and a lower part and arranged at the center of the tank so as to be rotated by a drive, bottom paddle blades attached to the lower part of the rotary shaft, each of said bottom paddle blades having a paddle surface which extends across a half of the apex angle of the conical bottom part and vertically extends up to the boundary between the cylindrical part and the conical bottom part, which has an external shape that is along a half of the apex angle of the conical bottom part, and which has an upper edge vertically located in the vicinity of the boundary, the lattice blades arranged in the cylindrical part, attached to the upper part of the rotary shaft, and composed of vertical grids each having an outer edge part, and horizontal arms supporting the vertical grids, each vertical grid having a blade surface which vertically extends substantially by a length from the top of the cylindrical part to the boundary, and which extends radially of said cylindrical part from the center thereof, wherein a distance between the outer edge part of the vertical grids, and the center of the rotary shaft is larger than a distance between the center of the rotary shaft and an outer end of the top edge of each of the bottom paddle blades, and the blade surface of each vertical grid having a radial width which is larger in the upper part thereof than in the lower part thereof.