| 摘要 |
PURPOSE:To quickly close a valve, to prevent a melt from invading the inside of a valve chest, and to improve the durability of a device, by making valve open holding force smaller than initial valve open holding force, after a prescribed time has elapsed from the time of starting a vacuum suction, and also, before an injected melt reaches the valve. CONSTITUTION:When a molten metal is poured into an injection sleeve, a vacuum suction device 70 is operated, gas in a cavity hits against the lower end of a valve body 24, and when inertia force of the molten metal exceeding valve open holding force works on the valve, the valve moves in the valve closing direction. In this case, when a piston 22 of the rear end part of a valve stem 23 ascends even a little, the lower face of the piston 22 is separated from an O ring 33, a fluid which has worked on the inside of a main chamber part 31 of the rod side works on the whole lower face, as well, or the piston 22, and the piston 22 ascends quickly. A valve seat 17e part is closed quickly and easily by the valve body 24, and the valve is held in a valve close state. |
