| 摘要 |
PURPOSE:To decrease the amt. of the curing gas to be used and to eliminate the need for any vent hole by putting a core box packed with molding sand incorporated with a gas curable binder into a sealed space and introducing the curing gas after holding the same under negative pressure. CONSTITUTION:A core box 3 packed with molding sand 2 incorporated with a gas curable binder is blaced on a molding board 1, and a cover 6 is brought down until it contacts with the top surface of the board 1, thereby forming a sealed space 13. A stop valve 5 is opened to maintain the inside of the space 13 under <=-700mm.Hg negative pressure, then a stop valve 8 is opened. A liquid curing gas 12 in a curing gas vessel 9 is introduced into the space 13 by the above-mentioned operation so as to be gassified and dispersed uniformly in said space, whereby the gas is penetrated in the molding sand 2. A combination of a pattern plate and a molding flask may be used in place of the core box. |
