| 摘要 |
PROBLEM TO BE SOLVED: To recycle gas without necessitating a recovery surge tank or the like by recovering injected gas through a communication between a vacuum part in which a cylinder chamber is made vacuum in its cylinder mechanism and a hollow part in which a pressurized gas is injected in the inner part of resin within the mold. SOLUTION: By keeping a charge valve 16 and gas bent valve 30 in a closed state, a gas injection valve 26 is changed over from its open state to its closed state and, simultaneously, a gas recovery valve 35 is changed over from its closed state to its open state. At this time, a front cylinder chamber 12 remains in a vacuum state. On the other hand, since the hollow part with filled gas of the mold 4 is in a highly pressurized state, gas in the hollow part moves into the front cylinder chamber 12 passing through a gas recovery passage 32 by the agency of pressure difference between the hollow inner part pressure and the front cylinder chamber 12 pressure, thereby completing gas recovery. After this, the gas vent valve 30 is opened so as to discharge a very small quantity of gas remaining in the passage outward. |
