PURPOSE: To obtain a defect-free high quality casting by providing a circuit for cooling a metallic mold at all times and an intermittent cooling circuit cooling the same only at necessary times.
CONSTITUTION: A plunger 7 is operated to force and pack molten metal into a metallic mold 1. Upon completion of the packing of the molten metal, a stop valve 9 provided to a bypass valve 8 is opened by the signal taken out from a pressure switch 12, by which cooling water is also supplied from the circuit 8 to the mold 1. At the same time, a timer 13 is operated and is timed up at a suitable timing between the solidification of the molten metal up to the removal of a casting, then the signal from the switch 12 is broken to close the valve 9, thereby stopping the supply of the cooling water from the bypass circuit 8. During this time, an ordinary cooling circuit 5 is oprating and therefore the temp. of the mold 1 is uniform without rising excessively above a constant temp. Hence, the mold 1 is maintained relatively at high temp. before the packing of the molten metal completes, and the gas discharged from the molten metal and the air in the metallic mold are prevented from forming water and steam.
MORIYA TOSHIAKI
KAWANO FUMIO
