| 摘要 |
PURPOSE:To harden molding sand in a short time, shorten gas passing time and improve the efficiency of molding work by putting a molded mold or core mold in an evacuated state and introducing a gaseous substance. CONSTITUTION:Mulled sand 3 molded in a mold or a box 1 is covered with a film 4 and is isolated from the atmosphere, whereby a kind of vacuum chamber is created. The clearances in the sand 3 are evacuated uniformly, after which CO2 is passed and therefore the gaseous CO2 passes uniformly through the sand. Since compressed air is introduced into a pipe 6 during passing of the gas, the CO2 conducted into the mold or box 1 flows in the direction of the pipe 5 and the entire part of the mold or the core reacts with the gaseous CO2 and hardens in a short time; at the same time, the gaseous CO2 escaping into air in an unreacted state is reduced. The similar effect is also obtained when this is adapted to a cold box method. |
