Abstract
This is prepared to report the series of the study on the recollecting method of molding sand published by the author several years ago. The previous study was of the dust exclusion method by the wind control which was best suitable to dry sand molding practice. But this method was not adaptable to green sand molding. This report is the result of the study on the dust exclusion method of green sand by the flutriation method. As to this method, being suggested by the mineral separator in mines, several step's gates were made on the way of stream, sand grains were deposited at each gate and only ultra-fines were removed with overflowed water. The apparatus in this report has a capacity of about four tons of sand a day. It requires about 8 cubic metres of water an hour. The results of the described treatment are as follows. 1. A grain distribution of recollected sand deposited at each step of the gate has each high peak point. 2. Compressive strength, permeability of sand and resistance for burning-on are remarkably improved. 3. This method saves naturally bonded sand. It is shown by the author's performance of half a year that seventy percent of sand consumption lessened. 4. Pieces of wood, stones and etc, in naturally bonded sand can be easily removed. This small device is suitable to a small and medium scale foundry, but the larger one ( 8 ton capacity a day) is being prepared as the mechanized. (T. Okakura)
