| 摘要 |
PURPOSE:To prevent a molten material from penetrating into a valve body while achieving a favorable degassing, by a method wherein a degassing valve in an opened condition is so engaged to be energized in the direction of a closed condition, and the engagement is released simultaneously with a closing action to close the valve completely. CONSTITUTION:A fixed mold 1 and a movable mold 2 are clamped, the valve 6 is lowered against a tension spring 13, and it is held in the opened condition by engaging it with an engaging mechanism 14 which consists of a recessed part 16 of a valve rod 6d and a ball 19 energized by a compression spring 18 provided at a valve rod guide part 12. When a molten material is injected into a cavity 3, the gas in the cavity 3 is discharged through a degassing passage 4, a degassing groove 5, a passage 7, a valve chamber 10 and a gas discharging port 11 as the cavity 3 is filled with the molten material. Then, the molten material flowing upwards through the groove 5 comes in contact with the lower surface of a valve head part 6a and pushes the valve 6 upwards, whereby the engagement by the mechanism 14 is released and the valve 6 is lifted up by the tension spring 13 to bring the valve head part 6a into contact with a valve seat 9, resulting in that the part between the passage 7 and the valve chamber 10 is closed completely. |
