Patent Grant
8888156
The present application is a U.S. National Phase filing of International Application No. PCT/FR2011/000492, filed on Sep. 6, 2011, designating the United States of America and claiming priority to French Patent Application No. 1003568, filed Sep. 8, 2010, and the present application claims priority to and the benefit of both of the above-identified applications, which are incorporated by reference herein in their entireties.
The invention relates to handling equipment used in aluminium production plants using igneous electrolysis by means of the Hall-Héroult process. It more particularly relates to devices for handling connectors which ensure the fastening and electrical contact of the anodes on the anode frame.
Metallic aluminum is produced industrially by igneous electrolysis, namely by electrolysis of alumina in solution in a molten cryolite bath, known as an electrolyte bath, using the well-known Hall-Héroult process. The electrolyte bath is contained in tanks, called “electrolysis tanks”, comprising a steel container, which is coated on the inside with refractory and/or insulating materials, and a cathodic unit located at the bottom of the tank. Anodes, typically made of carbonaceous material, are partially immersed in the electrolyte bath. The assembly formed by an electrolysis tank, its anodes and the electrolyte bath is called an electrolysis cell.
The anodes are provided with a metal stem for the electrical and mechanical connection to a metal framework, called an anode frame, which is mobile in relation to a fixed gantry placed above the electrolysis tank. The anode stems are connected to the anode frame using movable connectors that can be placed on support hooks located on either side of the anode rods and which can be maneuvered to pin the anode rods against the anode frame. French patent FR 2 039 543 (corresponding to U.S. Pat. No. 3,627,670) describes such devices, which have a tightening screw, the actuation of which allows the connector to be placed in tightened configuration, where it pins the anode rod against the anode frame thus ensuring electrical contact, and in a loosened configuration where it can be removed to enable disconnection from the anode rod.
When in operation, an electrolysis plant requires servicing work on the electrolysis cells, including the replacement of worn anodes by new anodes. In order to carry out this servicing work, plants are generally equipped with at least one lifting and handling unit comprising an overhead crane which can be moved above and along the electrolysis cells, and a carriage provided with several handling and servicing devices (often called “tools”). Such a lifting and handling unit may, in particular, be equipped with a device for handling connectors, notably their placement, removal and transport, such as the connector described in French patent FR 2 039 543.
It may occur, however, that the connectors are not properly seized by these handling devices, and this may lead to the connector being dropped accidentally, typically during its transport or during its placement on the support hooks. In its U.S. Pat. No. 7,344,625, the applicant proposed a handling device for single anode connectors of compact design. This handling device is designed to place, remove and transport an anode connector equipped with two side trunnions and a tightening screw, such as that disclosed by U.S. Pat. No. 7,344,625 and again illustrated in
In this device, the mobile members pass from one position to another under the action of cams that cooperate with the upper surface of the support hooks during the vertical descending movement of the handling device. In practice, these mobile members are subjected to frequent impacts and become easily bent or twisted, such that they become stuck or close and that their extremity no longer passing below the trunnions, they end up no longer being able to perform the role of safety support in the event the connector would no longer be retained by the locking system. This requires numerous maintenance inspections of this device which results in frequent replacement of said mobile members. To void these drawbacks, the applicant decided to develop a connector handling device that is sturdier and more reliable.
The subject of the invention is a handling device designed in particular to ensure reliable and durable transport of an electrolysis cell anode connector, the placement and fastening of the anode connector on an anode frame in order to ensure electrical contact between the anode stem and the anode frame, or its removal, the handling device being arranged so that the risk of accidental dropping of said connector during its handling is as low as possible.
A first purpose of the invention is a device for handling a connector to connect an anode stem onto the anode frame of an aluminium production plant using igneous electrolysis, said connector being equipped with two side trunnions able to cooperate with support hooks interdependent with said anode frame and placed on either side of the anode stem, so as to pin said anode stem against said anode frame, said handling device comprising at least a guiding device having a notch associated with each of said trunnions and designed to receive said trunnion, said handling device being characterized in that it also includes:
The arrangement of the gripping member and the locking system is such that:
In contrast to the handling device described in U.S. Pat. No. 7,344,625, the locking of the connector in the handling device is not dependent on the tightening-loosening device of the connector, and thus may be used to handle connectors of different types, for example which do not require actuation of a tightening screw. However, the preferred embodiment of the invention, designed to handle connectors equipped with a tightening screw, is also equipped with a tightening/loosening device of the tightening screw of the connector, the later not necessarily being associated with the locking system of the connector.
The mobile members of U.S. Pat. No. 7,344,625, which are used as safety supports by the trunnions, are replaced here by a gripping member designed to be used as a “permanent” support for said trunnions when they are in low position in the notches of said handling device. The gripping member is moved between its open position and its closed position by means of autonomous actuating system. In this manner, the movement of the gripping member, which is no longer dependent on the action of cams cooperating with the upper surface of the hooks, can be made regardless of the condition, worn or deformed, of said gripping member.
Moreover, the gripping member is associated with a locking system that can unlock—enabling the handling device to pass from its closed position to its open position—only if the trunnions of the connector, introduced into the notches, are located in high position. The locking system comprises a moving part designed to move between two positions: an unlocked position, where the gripping member is free to move and a locked position, where it prevents movement of the gripping member, in the direction of its open position if it is in closed position and in the direction of its closed position if it is in open position. Advantageously, the unlocked position is reached by said moving part when it enters into contact with a trunnion and is driven by said trunnion in its travel toward its high position. This moving part may move by pivoting around a pin interdependent with the handling device of the connector or by being guided in translation by a sliding type connection.
Advantageously, said locking system is associated with an actuator which, when said trunnion is not in high position, moves said moving part from its unlocked position to its locked position. Thus, as soon as the trunnion is no longer in high position, the locking system is in its locked position, which prevents the untimely opening or closing of the gripping member. Said actuator is an elastic means, typically a compression spring, the stiffness of which is sufficiently weak so that the mobile part of the locking system can be driven by said trunnion in its movement toward its high position.
In normal operation, the high position of the trunnions can only be reached by downward movement of the handling device, the connector being fixed, typically resting on the support hooks of the anode frame.
Advantageously, the actuating system of the gripping member is a cylinder, typically pneumatic, comprising a rod, the two extremities of travel of which correspond to said open position and said closed position, respectively. Advantageously, position sensors are provided to identify the position of the moving part of the locking system, so as to prevent implementation of the actuating system when the locking system is in locked position (redundant safety).
In a preferred embodiment of the invention, the gripping member comprises two flanges, each associated with a trunnion and driven by the same actuating system. Furthermore, the locking system advantageously includes two locking devices, each associated with a trunnion.
Said gripping member is advantageously a pivoting member, preferably a set of pivoting flanges, the exterior contour of which, in a plane perpendicular to the pivot axis, presents a tongue or groove type relief, which cooperates with a relief of the locking system, and a relief, which forms an obstacle at the entrance of the notch, when said gripping member is in closed position, and which typically features a concavity able to form a seat on which the trunnion can rest. The overall C- or L-shapes are well adapted to this pivoting member although other more compact shapes, such as those presented in example 4, may also be suitable.
The moving part of the locking system is advantageously equipped with two partitions which, when said moving part is in locked position, form stops that halt the movement of said relief of the gripping member: an opening stop partition which counters the movement of said relief when said gripping member must pass from its closed position to its open position and a closure stop partition which counters the movement of said relief when said gripping member must pass from its open position to its closed position.
Another subject of the invention is a lifting and handling unit comprising at least a connector handling device according to the invention.
Another subject of the invention concerns the use of the handling device according to the invention in a plant for the production of aluminum by igneous electrolysis.
Another subject of the invention concerns the use of the lifting and handling unit according to the invention in a plant for the production of aluminum by igneous electrolysis.
The invention shall be better understood with the help of the detailed description of the preferred embodiments of the invention and are illustrated in the figures enclosed in the appendices.
a to 4d are side views of a first connector handling device according to the invention, with its mounting plate.
a to 5d are side views of a second connector handling device according to the invention.
a to 6d are side views of a third connector handling device according to the invention.
a to 7d are side views of a fourth connector handling device according to the invention.
Electrolysis plants designed to produce aluminium include one or more electrolysis halls (100) comprising a large number of electrolysis cells (1) normally arranged in rows or lines (typically side by side or head to head), each row or line typically comprising one hundred or several hundreds of cells. As illustrated in
The anode rods (9) are secured to the anode frame (5) by connectors such as those illustrated in
A connector (200) has at least a first state, referred to as the tightened state, and a second state, referred to as the loosened state. When a connector (200) is installed in fastening hooks (10, 10′), as illustrated in
A connector (200) can pass between the two tightening states by actuating tightening means (205, 206, 210, 211). These means typically include a screw (210) able to cooperate with an external tightening member, generally fixed to a handling device (300). The tightening screw (210) is typically equipped with a head (211) that can be inserted into the tightening member, which is actuated by tightening or loosening the connector (200). The tightening means equally include nuts (205, 206) fastened to levers (201, 202) of the connector, preferably in a mobile manner, and able to cooperate with the screw (210) so as to allow the pivoting of the levers (201, 202) and the tightening/loosening of the connector (200). The levers (201, 202) of a connector (200) generally comprise cross members (203, 204) designed in particular to communicate, directly or indirectly, the tightening pressure of the connector against the anode rods.
As illustrated in
Examples 1 to 4 illustrate four embodiments of the connector handling device according to the invention, that essentially differ by the shape given to the gripping member and by the locking system.
The first example is a connector handling device (300) which is mounted on the end of a telescopic arm by means of a mounting plate (301). Said handling device includes a guiding member (30) which has a notch (40) associated with each of said trunnions and into which said trunnion is intended to move.
The handling device also includes a gripping member (31), which has an open position and a closed position. The guiding member (30) and the gripping member (30) cooperate such that:
A pneumatic cylinder acts as the actuating system (311) associated with said gripping member, able to move it between said open and closed positions.
A pivoting L-shaped latch (320) is the moving part of the locking system (32). It features a locked position and an unlocked position, able to lock the gripping member (31) when in locked position. The pivoting axis (322) of said latch is essentially located at the junction of the two branches of the L, the first branch (321) of the L, essentially horizontal, being designed to come into contact with said trunnion when it moves from its low position toward its high position and to be driven by said trunnion, making the latch pivot toward its locked position. The second branch (325) of the L, essentially vertical, has a surface irregularity that cooperates, when said latch is in locked position, with a part in relief (313) of the gripping member (31) so that it counters all movement of said gripping member, regardless of its original position, open or closed: its lower partition (324) forms a closure stop, and its upper partition (323) forms an opening stop.
When the handling device (300) is equipped with a connector and moves in order to place it on the support hooks of the anode frame, the latch (320) is in locked position and blocks the gripping member (31) in closed position, trapping the trunnions of the connector. By gravity, the trunnions are in low position, in contact with the gripping member (
When the handling device (300) is empty and is moved in order to grasp a connector resting on the support hooks of the anode frame and to extract it from this position, the gripping member is maintained in open position. Upon arriving above the connector (
An actuator (34) moves the locking system (32) from its unlocked position to its locked position when the trunnion is not in high position. Said actuator is a spring (340), connecting a fixed point of the handling device to a point of the essentially vertical branch of the L. The stiffness of the spring is sufficiently weak so that the latch can pivot when the trunnion comes into contact with the essentially horizontal part.
The gripping member (31) includes two pivoting flanges, each associated with a trunnion and driven by a cylinder to move from the open position to the closed position and vice-versa. Said flanges pivot around a pin (302). These flanges have a C-shaped contour, with a relief (313) of tongue type which cooperates with the upper partition (323) and the lower partition (324) of the latch (320) and with a protuberance (314) which forms an obstacle at the entrance of the notch, when said gripping member is in closed position. The protuberance (314) has a concavity (312) able to former a seat on which the trunnion can rest.
The second example essentially differs from the first example by the latch (320′). The latter is also a pivoting L-shaped latch, with a very short substantially vertical branch, connected to a compression spring (340′) and a substantially horizontal branch equipped with a slot having an opening stop partition (323′) and equipped, at its end, with a closure stop partition (324′).
The pin (313′) of the flange (310′) of the gripping system (31) cooperates with said opening stop partition to maintain the locking system (31) in locked position, said flange being blocked in closed position. The pin (313′) cooperates with said closure stop partition (324′) to maintain the locking system (31) in locked position, the flange (310′) of the gripping system (31) being blocked in open position.
The third example essentially differs from the first example by the latch (320″). The latter does not pivot: it moves vertically, guided by a slide (322″). Its upper end is connected to a compression spring (340″) which tends to push it toward a low position, in which the opening stop partition (323″) and the closure stop partition (324″) interact with the pin (313″) of the flange (310″) in a manner similar to that described in the previous example.
The fourth example differs from the previous examples relative to the more compact shape of the flanges (310′″) of the gripping system (31). The latch (320′″) pivots. A compression spring (340′″) tends to push it toward a low position, in which the opening stop partition (323′″) and the closure stop partition (324′″) interact with the pin (313′″) of the flange (310′″) in a manner similar to that described in examples 2 and 3 above.
In this example, the movements of the flanges (310′″) of the gripping system (31) are less ample, the seat (312′″) provided to the trunnions is less extensive although the associated protuberance (314′″) allows said trunnions to be trapped in the notch.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 03568 | Sep 2010 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR2011/000492 | 9/6/2011 | WO | 00 | 3/7/2013 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2012/032234 | 3/15/2012 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3167345 | Dukes | Jan 1965 | A |
| 3434955 | Duclaux | Mar 1969 | A |
| 3625558 | Johnson | Dec 1971 | A |
| 3627670 | Duclaux | Dec 1971 | A |
| 4609219 | Go | Sep 1986 | A |
| 5114200 | Visnyouszky et al. | May 1992 | A |
| 7344625 | Delescluse | Mar 2008 | B2 |
| 20050266735 | Delescluse | Dec 2005 | A1 |
| 20060290153 | Delescluse | Dec 2006 | A1 |
| Number | Date | Country |
|---|---|---|
| 1876265 | Jan 2008 | EP |
| 2039543 | Jan 1971 | FR |
| 2854906 | Nov 2004 | FR |
| Entry |
|---|
| International Search Report mailed Oct. 31, 2011 (PCT/FR2011/000492); ISA/EP. |
| Number | Date | Country | |
|---|---|---|---|
| 20130181468 A1 | Jul 2013 | US |
