| 摘要 |
A method and a device for controlling the movement of a combined alumina feeding and crust breaking chisel in an aluminum production cell, wherein th e chisel is moved downwards and upwards by means of a pneumatic cylinder which is alternatively fed with pressurized air, wherein electrical contact betwee n the chisel and the melt is detected when the chisel reaches the melt, wherei n it is monitored whether said electrical contact has been reached within a predetermined time interval, and if not, air at a second, high, pressure is fed to said first, and wherein air at high pressure is fed to the second sid e of the cylinder after said electrical contact has been established so as to quickly withdraw the chisel from the hot melt in order to minimize heat transfer from the melt to the cylinder.
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