Device for extracting short-circuiting wedges when switching in an electrolysis cell for the production of aluminum

Abstract

Extraction device designed to extract a short-circuiting wedge inserted between two conductors to take an electrolysis cell offline. The extraction device includes a means of gripping said wedge and at least one jack directed vertically and including a body and a piston stem. said body (or stern) being interdependent with at least one horizontal support face directed downwards and laid out so that, when said extraction device is placed above said wedge to extract it, the upper horizontal face of each conductor is in line with one horizontal support face, b) said stem (or said body) being connected to said means of gripping said wedge, so that, when said jack is actuated to extract the wedge, said jack exerts opposing forces on said conductors and said wedge, tending to separate them.

1 . Extraction device designed to extract a short-circuiting wedge, said wedge having been inserted between two conductors to take an electrolytic cell off line, each conductor having at least one upper horizontal face and one substantially vertical face, the substantially vertical face of each conductor being placed opposite the substantially vertical face of the other conductor, the two substantially vertical faces thereby delimiting an air-gap designed to receive said short-circuiting wedge, said wedge comprising two substantially parallel faces, which converge slightly to a bottom of said wedge when said wedge is placed so as to occupy said air-gap, said device including a means of gripping said wedge, wherein said device includes at least one jack directed vertically and comprising a body and a piston associated with a piston stem, wherein:
 a) one of said body or said stem is interdependent with at least one horizontal support face which is directed downwards and configured so that, when said extraction device is placed above said wedge to extract the wedge, the upper horizontal face of each conductor is in line with the horizontal support face, and   b) the other of said stem or said body is connected to said means of gripping said wedge, so that, when said at least one jack is actuated to extract the wedge, said at least one jack is configured to exert opposing forces on said conductors and said wedge, tending to separate said conductors and said wedge.   
     
     
         2 . Extraction device according to  claim 1  characterized in that said means of gripping includes a fixing part onto which are attached means of fixing working in conjunction with means of fixing engineered in the top part of the wedge which is designed to remain above the air-gap of the conductors when the wedge is inserted into the air gap. 
     
     
         3 . Extraction device according to  claim 1  characterized in that said at least one jack is a hydraulic actuating cylinder. 
     
     
         4 . Extraction device according to  claim 1  characterized in that the device also includes an actuator designed to raise, as soon as the wedge is no longer held by the conductors, a unit including the wedge, the means of gripping said wedge and said at least one jack so that said unit comes out of said air-gap between said conductors. 
     
     
         5 . Extraction device according to  claim 4 , characterized in that said actuator is a pneumatic jack. 
     
     
         6 . Extraction device according to  claim 4 , characterized in that said at least one jack and said actuator are configured to operate simultaneously during the extraction of said wedge. 
     
     
         7 . Extraction device according to  claim 6  characterized in that the device also includes a frame onto which is fixed said actuator, said frame including means of fixing, so that said frame can be handled by transport and lifting means. 
     
     
         8 . Extraction device according to  claim 7 , characterized in that said frame is provided with means of centering configured to guide said extraction device during vertical movement downwards towards a predefined position in relation to said conductors, the support faces being placed in line with the upper horizontal faces of said conductors. 
     
     
         9 . Extraction device according to  claim 7 , characterized in that said frame also includes fairing which delimits the space in which the unit including the wedge and the means of gripping the wedge must move after said wedge has been extracted and which provides protection for operators working near said extractor. 
     
     
         10 . Extraction device according to  claim 1 , including an intermediate hollow part provided with a horizontal support face directed downwards and in which the body of the at least one jack is interdependent, via said part intermediate hollow part, with said the horizontal support face, the upper horizontal face of each conductor being in line with said horizontal support face when said device is positioned for the extraction of said wedge. 
     
     
         11 . Extraction device according to  claim 10 , in which the body of the at least one jack has a lower horizontal face which is in contact with the upper horizontal face of said intermediate part when the extraction device is placed on said conductors in order to extract said wedge. 
     
     
         12 . Extraction device according to  claim 10 , in which the stem of the at least one jack is hollow, passing right through via an axial bore through which an axle interdependent with said means of gripping of the wedge can slide. 
     
     
         13 . Extraction device according to  claim 12 , in which said axle interdependent with the means of gripping is provided with a shoulder which serves as a stop for the axial movement of stem, so that, when said at least one jack is operated, stem is entrained upwards, the end of said stem comes into contact with the shoulder of said axle, so that said at least one jack is configured to exerts an upwards force on said gripping device. 
     
     
         14 . Extraction device according to  claim 12 , in which said means of gripping the wedge is fixed to a lower end of the axle, and wherein the axle is an extension of the piston stem of the actuator. 
     
     
         15 . Extraction process for short-circuiting wedges used when switching in an electrolytic cell comprising removing a short-circuiting wedges which was inserted between first and second conductors to take said electrolytic cell off line, the first conductor being associated with a cathode assembly of said cell and the second conductor being associated with a cathode assembly of an adjacent upstream cell, the first and second conductors each having at least one upper horizontal face and a substantially vertical face, the substantially vertical face of the first conductor being placed opposite the substantially vertical face of the second conductor, the two substantially vertical faces delimiting an air-gap designed to receive said short-circuiting wedge, said wedge including two substantially parallel faces, which converge slightly towards a bottom of said wedge when said wedge is placed so as to occupy said air-gap, said process being characterized in that an extraction device is used for removing the wedge, the extraction device including a means of gripping said wedge, wherein said device includes at least one jack directed vertically and comprising a body and a piston associated with a piston stern, wherein:
 a) one of said body or said stem is interdependent with at least one horizontal support face which is directed downwards and laid out so that, when said extraction device is placed above said wedge to extract the wedge, the upper horizontal face of each of the first and second conductors is in line with the horizontal support face, and   b) the other of said stem or said body is connected to said means of gripping said wedge, so that, when said at least one jack is actuated to extract the wedge, said at least one jack exerts opposing forces on said first and second conductors and said wedge, tending to separate the first and second conductors and the wedge.