| 摘要 |
PURPOSE:To reduce consumption of the refrigerant when frozen molds are manufactured, by penetrating the refrigerant into molds made of molding sand with a pressure from narrow holes or tubes installed in the cover plate of patterns and molds. CONSTITUTION:A pattern 3 of casting having a plural number of narrow holes 4 connected to a conduit 2, is placed on a molding board 1 provided with the counduit 2. Then, this is set in a molding flask 5 and molding sand containing 3-5% moisture is charged in the space between the model 3 and the molding flask 5. A covering plate 6 provided with another counduit 7 and numerous branch tubes 8 having many narrow holes 9, is put on the molding flask 5. A refrigerant, such as liquid nitrogen, etc., is compressedly supplied through the conduits 2 and 7 and the refrigerant is introduced into the molding sand through the narrow holes 4 and narrow holes 9 of branch tubes 8. Thus a frozen mold is manufactured by freezing the formed body made of molding sand and containing some % of moisture. Because the mold is frozen from the inside by penetrating the refrigerant into the mold made of molding sand, the effective coefficient of utilization of the refrigerant becomes higher and it can be used economically. |
