APPARATUS AND METHOD FOR MIXING SHORT FIBER WITH AIR BUBBLE

PROBLEM TO BE SOLVED: To provide an apparatus and a method for applying pretreatment to short fibers before mixing the short fibers to chief materials so that the short fibers mixed as reinforcing materials: do not cause entanglement and clogging to the chief materials, in the chief materials; and can maintain a uniform dispersed state in the chief materials.SOLUTION: A mixing apparatus is provided for mixing short fibers for use as reinforcing materials of chief materials being solidification materials or earth and sand with air bubbles before being supplied to the chief materials. The apparatus is provided with three pipes connected substantially in Y-shape so as to form one junction. The apparatus has an inlet of the short fibers at an upper end of the first pipe extending upward from the junction, has an inlet of air bubbles at an upper end of the second pipe extending upward from the junction, and has an outlet of a mixture of the short fibers and the air bubbles at a lower end of the third pipe extending downward from the junction. Preferably, the first pipe may extend vertically upward, and the second pipe may form an angle of 20° to 40° with respect to the first pipe.