| 摘要 |
PURPOSE:To reduce the time lag and to prevent invasion of molten metal into sliding part in each valve body, by shorting out molten metal detecting sensor at the time of reaching of the molten metal and shutting off a conical valve by working a switching circuit, to execute the venting. CONSTITUTION:The molten metal 12 is reached to a venting groove 10 after filling up a cavity 9 and shorted out between two electrodes of the molten metal sensor 4, and a solenoid valve 21 for working air is worked by the switching circuit 20 and compressed air is flowed in a cylinder 28 through a supplying/exhausting hole 27 for working air of a gas ventilating value 1 from an air source 23. Then, a conical piston 29 is gone to right direction and also the conical value 5 integrated with it is gone to right direction, to shut off a gap 8 for venting. The gas ventilating valve 1 is shutted off at earlier than reaching time of the molten metal to a position 11 from the venting groove 10, to vent surely the gas in the cavity. |
