To realize a uniform cooling in a short period of time by a method wherein an air circulating operation, in which the blowing of air in the inner space of a molding is executed from the starting end side of an air flow and the exhausting of the air in the inner space of the molding is executed from terminal end side of the air flow, and a continuous or intermittent mist spraying, which is executed from the starting end side of the air flow, are carried out in a blow molding process.
In each air charging and discharging nozzle 12, an air feeding passage 13 and an air exhausting passage are formed by separating them from each other with a partition wall 122 and a mist nozzle 15 is provided in the air feeding passage 13. By sticking the air charging and discharging nozzle 12 into a parison, a blowing air is blown from the air feeding passage 13 so as to detect the arrival of the pressure in the parison to the predetermined pressure with a pressure detector 17 for transferring to a cooling process. At this time, a mist is sprayed from the mist nozzle 15 for quenching the inner surface of the parison. Next, a cooling air is blown from one of the air charging and discharging nozzles 12 and released from the other one of the air charging and discharging nozzles 12 through a relief valve 16 to a fresh air, resulting in developing an air circulating flow. Thus, the inner surface of a molding is further more uniformly cooled.
NAGAHORI KAZUTOSHI
CHIBA SATOSHI
PLACO CO LTD
TOHO ACETYLENE CO LTD
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