Patent FR-2874934-A1 (FR)
Title: Changing anode of electrolytic cell for production of aluminum, by producing beam of sound or electromagnetic waves along determined reference line or in reference plane, and placing gripping device in position of metal rod of spent anode
Inventor: VAN ACKER ALAIN
IPC: C25D17/10
Filed: 2004-09-08
Abstract: Changing an anode of cell for production of aluminum, comprises producing beam(s) of sound or electromagnetic waves along determined reference line or in determined reference plane, and in that for each determined spent anode, a gripping device is placed in gripping position of metal rod of spent anode, and the vertical distance A traveled by gripping device to reach the position is measured. The spent anode is withdrawn from cell. Changing an anode of electrolytic cell (2) for production of aluminum, comprises using fused bath electrolysis comprising anodes (20, 20'), electrolytic bath (33) and cathode block (29), each anode comprising at least one anode block (21, 21') and a metal rod (22, 22') and being fixed removably by mechanical attachment unit (24, 25) to a mobile metal frame (23). Each anode block has a reference surface (21a, 21a'). At least one determined spent anode is replaced by a replacement anode using at least one anode handling tool comprising a positioning device, a gripping device and a sensor to determine the vertical position of the gripping device. The position sensor of the anode handling tool or each anode handling tool is used to measure the vertical distances traveled by the gripping device or each gripping device relative to a reference level N. At least one beam of sound or electromagnetic waves is produced along a determined reference line or in a determined reference plane, and in that for each determined spent anode, a gripping device is placed in the gripping position of the metal rod of the spent anode, and the vertical distance A traveled by the gripping device to reach the position is measured. The spent anode is withdrawn from the electrolytic cell, the anode block of this anode is passed through the beam in a vertical movement and the vertical distance B traveled by the gripping device at the moment at which the reference surface of this anode passes through the beam is measured. The metal rod of a replacement anode is gripped using a gripping device. The anode block of this anode is passed through the beam in a vertical movement and the vertical distance C traveled by the gripping device at the moment at which the reference surface of this anode passes through the beam is measured. The vertical position of the replacement anode in the cell is determined starting from values obtained for the traveled distances A, B and C, and the replacement anode is put into this position in the place initially occupied by the spent anode. Independent claims are also included for: (A) Measurement system comprising a position sensor to measure the vertical distances traveled by an anode gripping device, a sound or electromagnetic waves beam generator capable of generating at least one sound or electromagnetic waves beam along a determined reference line or in a determined reference plane, at least one sound or electromagnetic wave detector capable of detecting the passage of a determined part of an anode through the beam and at least one positioning device to which the generator and/or the detector is fixed; (B) a tending machine intended for anode replacement operations in a series of cells for the production of aluminum by fused bath electrolysis, comprising at least one anode handling tool comprising a positioning device and a gripping device comprising a measurement system according to claim 21; and (C) a tending assembly in a plant for the production of aluminum by fused bath electrolysis comprising a traveling crane and at least one tending machine according to claim 35.