PURPOSE: To maintain the temperature of cooling water constant at all times to stabilize the cooling capacity by controlling the quantity of cooling water to be supplied according to a signal of a detecting device for the temperature of the cooling water which is fitted to a cooling-water outlet piping of a mold.
CONSTITUTION: The cooling capacity of cooling water changes momentarily according to the changes in a heat from plastic molding dies 1 and 2 and in the temperature of cooling water supplied. Therefore, the change in the temperature of water is detected by a cooling-water temperature detecting device 6 fitted to a cooling-water outlet piping 4, and a signal of the device is sent to a pump 5 of which the number of rotations is variable. Thereby the number of rotations of the pump 5 is increased when the temperature of water is high, while it is decreased when the temperature falls, and thus the quantity of water supplied by the pump 5 is changed. By this constitution, the stable cooling capacity is secured constantly, a molding cycle is thereby shortened, and the quality of products is stabilized.
YAZAKI YUKIHIRO
MURAKAMI KIYOUSHIROU
