Patent Application
20050266735
1. Field of the Invention
The invention relates to devices useful in an aluminum production plant employing fused bath electrolysis using the Hall-Héroult process. In particular, the present invention is directed to handling devices and related equipment useful in such plants.
2. Description of Related Art
Aluminum metal can be produced industrially by fused bath electrolysis, namely by electrolysis of alumina in solution in a molten cryolite bath called an electrolyte bath, using, for example, the well-known Hall-Héroult process. The electrolyte bath can be contained in pots called “electrolytic pots” comprising a steel pot shell that is lined on the inside with refractory and/or insulating materials, and a cathode assembly located in the bottom of the pot. Anodes, typically made of a carbonaceous material, are partially immersed in the electrolyte bath. The assembly formed by an electrolytic pot, its anodes and its electrolyte bath, is called an electrolytic cell.
The anodes are provided with a metallic stem used for the electrical and mechanical connection to a metallic frame called the anode frame, which is mobile with respect to a fixed gantry placed above the electrolysis pot. The anode stems are connected to the anode frame by hooks arranged on each side of the anode stems and removable connectors that fit on these hooks and force the anode stems into contact with the anode frame. French patent FR 2 039 543 (corresponding to U.S. Pat. No. 3,627,670) describes certain devices of this type.
During operation, an electrolysis plant requires work on electrolytic cells, particularly including the replacement of spent anodes by new anodes. The most modem plants are provided with at least one lifting and handling unit comprising a traveling crane that can be moved above and along the electrolytic cells, and a carriage fitted with several handling and work devices (often called “tools”) the facilitate the replacement of anodes and other operations.
French patent FR 2 039 543 describes a handling device designed for handling connectors, and particularly placement, removal and transport of these connectors.
It often arises that connectors are not well gripped by well-known handling devices, which can cause accidents such as dropping of the connector, typically during transport or during placement.
The present invention relates to an anode connector handling device designed for use by the aluminum production industry, that avoid certain of the above disadvantages but that remain reliable, simple and compact.
An object of the invention was therefore to provide a handling device designed particularly for placement and removal of an electrolytic cell anode connector.
More precisely, an object of the invention was the provision of a handling device for an anode connector provided with two side trunnions and a tightening screw, wherein the handling device comprises a tightening device such as a spanner (or wrench), capable of cooperating with the tightening screw of the connector so as to modify its tightening state. The handling device further comprises a locking system capable of cooperating with the tightening device and the connector to lock it in a determined position (called the normal handling position) in the handling device by loosening the connector using the tightening device. The handling device further preferably comprises at least one mobile member having an open position and a closed position, and wherein the mobile member comprises a support capable of supporting the connector (typically by its side trunnions) when it is in the closed position and a means of displacing the mobile member from the closed position to the open position.
The applicant had the idea of providing the handling device with a locking system designed to maintain the connector in a normal handling position and a mobile member designed to act as a support if a locking failure occurs in the handling device. Thus the support of the mobile member provides a safety locking means when the connector is not in the normal handling position. For example, this type of failure could occur when the connector has been damaged or deformed or is worn.
Another object of the invention was to provide an anode connector provided with a gripping means capable of cooperating with a handling device locking system.
Another object of the invention was to provide a lifting and handling unit comprising at least one anode connector handling device according to the invention.
Yet another object of the invention was to provide a fused bath electrolysis aluminum plant that employs a handling device according to the invention.
Still yet another object of the invention was the provision of a fused bath electrolysis aluminum production cell that employs a connector according to the present invention.
And another object of the invention was a lifting and handling unit according to the invention employed in a fused bath electrolysis aluminum production plant.
Additional objects, features and advantages of the invention will be set forth in the description which follows, and in part, will be obvious from the description, or may be learned by practice of the invention. The objects, features and advantages of the invention may be realized and obtained by means of the instrumentalities and combination particularly pointed out in the appended claims.
The invention will be better understood after reading the detailed description of a preferred embodiment of it as described below, illustrated with reference to the attached figures.
The invention reduces the chance, or even prevents a connector from accidentally being dropped during handling. It has the advantage that it requires only a limited number of mobile elements, which increases the reliability of the handling device.
Further handling devices of the present invention are capable of being used for handling an anode connector having at least two side trunnions and a screw, and comprise a locking system designed to maintain the connector in a normal handling position and a at least one mobile member designed to act as a support if a locking failure occurs in the handling device.
Electrolysis plants designed for aluminum production typically comprise one or several electrolysis rooms (100) with a large number of electrolytic cells (1) normally arranged in rows or lines (typically side by side or end to end), each row or line typically comprising one or several hundred cells.
As illustrated in
The anode stems (9) are advantageously fixed to the anode frame (5) by connectors (200) typically comprising two levers (201, 202) capable of articulating about a common axis (213), tightening means (205, 206, 210, 211) to articulate the levers (201, 202) and two side trunnions (or studs) (212, 212′) located on each side of the connector. The side trunnions (212, 212′) usually form a common axis (213) and are typically comprised of the ends of a stem (usually cylindrical) that passes through the connector from one side to the other. The trunnions (212, 212′) remain in the hollow (11, 11′) formed by the hooks (10, 10′) fixed to the anode frame (5) and located on each side of each anode stem (9).
A connector (200) has at least a first state called the tight state, and a second state called the loose state. When a connector (200) is installed in the attachment hooks (10, 10′) as illustrated in
A connector (200) may change between two states of tightness by actuating the tightening means (205, 206, 210, 211). These means normally comprises a screw (210) capable of cooperating with an external tightening device (302) such as a spanner (wrench), usually fixed to a handling device (300). The tightening screw (210) is typically provided with a head (211) that can be inserted in the tightening device (302) to tighten or loosen the connector (200). The tightening means also preferably includes nuts or similar attaching mechanisms (205, 206) fixed to connector levers (201, 202), preferably free to move, and capable of cooperating with the screw (210) so as to enable articulation of the levers (201, 202) and tightening/loosening of the connector (200).
The levers (201, 202) of a connector (200) generally comprise cross-pieces (203, 204) intended particularly to directly or indirectly transfer the connector tightening pressure into contact with anode stems.
As illustrated in
According to the present invention, the handling device (300) of an anode connector (200) provided with two side trunnions (212, 212′) and a tightening screw (210), the connector being capable of cooperating with attachment hooks (10, 10′) of an aluminum production cell (1) that employs fused bath electrolysis so as to enable connection of anodes (8) onto the cell. The handling device comprises a tightening device (202) capable of cooperating with the tightening screw (210) so as to modify the tightening state of the connector (200). The handling device comprises a locking system (310, 310′, 320) capable of cooperating with the tightening device (302) and the connector (200) so as to lock the connector in a desired position in the handling device (300), by loosening the connector (200) using the tightening device (302). The handling device also comprises at least one mobile member (312, 312′) with a first position called the open position and a second position called the closed position. The at least one mobile member (312, 312′) preferably comprises a support (313, 313′) capable of supporting the connector (200) when it is in the closed position and also includes a means (315, 315′) of causing displacement of the at least one mobile member (312, 312′) from the closed position to the open position.
The “desired position” is also referred to herein as “the normal handling position.” In the normal position, the connector is correctly anchored in the handling device, unless a problem arises, and can be displaced and transported. In the normal handling position, the support (313, 313′) is typically not needed to carry the connector; in other words the support is only designed to carry the connector in the case of a failure. Furthermore, in the normal handling position, the tightening screw (210) normally remains engaged in the tightening device (302). The connector (200) can then be pulled out or withdrawn from the normal handling position by tightening the connector using the tightening device (302).
In one advantageous embodiment of the invention, the support (313, 313′) is capable of supporting the connector (200) through the side trunnions (212, 212′) when one or more of the mobile members (312, 312′) is in the closed position. This embodiment provides excellent stability to the connector when it is placed on the support. In this embodiment, the support (313, 313′) is advantageously provided with a concave recess (314, 314′) that is oriented essentially downward during use, such that a trunnion (212, 212′) of the connector can fit into this recess.
In one particularly advantageous embodiment of the invention, the at least one mobile member (312, 312′) also comprises a safety locking means (314, 314′) to impede or prevent displacement of the mobile member or each mobile member (312, 312′) from the closed position to the open position when the connector (200) is resting on the support (313, 313′). This situation can arise when the connector is not locked (or not correctly locked) in the normal handling position, in which case the connector can be drawn downwards by gravity until it rests on the support (313, 313′). This situation may also arise when the connector is released from its normal position during handling, typically following a false maneuver. This embodiment prevents an operator from attempting to install a connector that is badly fixed in the handling device, which could make the connector drop.
In one preferred embodiment of this embodiment of the invention, the handling device comprises two mobile members (312, 312′) each comprising a support (313, 313′), and each support (313, 313′) comprises at least one recess (314, 314′) in which a side trunnion (212, 212′) can be fitted. The dimensions of each recess (314, 314′) are such that when the connector is locked in the desired position (called the normal position), each mobile member (312, 312′) can move without being hindered; whereas when the side trunnions (212, 212′) of the connector (200) rest in the recesses (314, 314′), displacement of the mobile member (312, 312′) is mechanically impeded, or preferably substantially prevented, by a stop effect, formed by the safety locking means.
The mobile member (312, 312′) is typically capable of being moved by pivoting about an axis (303).
In one advantageous embodiment of the invention, the locking system (310, 310′, 320) comprises at least one attachment means (320) that can cooperate with the connector (200) and the tightening device (302) so as to lock the connector (200) in the handling device (300). The attachment means (320) is typically able to cooperate with the connector (200) through a gripping means (231, 232) provided on the connector.
Cooperation between the connector (200), the tightening device (302) and the attachment means (320) fixes the connector in the handling device when the connector (200) is loosened. For example, as illustrated in
The attachment means (320) is advantageously a fixed or mobile part capable of cooperating with the connector (200), typically by insertion in a gripping means (231, 232) provided on the connector, so as to lock it. The attachment means (320) is typically a stud, a pin or a protuberance or any other desired similar device.
It was found advantageous to fix the attachment means (320) to the guide means (310, 310′).
In one advantageous embodiment of the invention, the locking system (310, 310′, 320) comprises at least one guide means (310, 310′) that may be fixed or mobile, designed to guide insertion of the connector into the locking system. The guide means (310, 310′) typically comprises a fork. The system preferably comprises two forks (310, 310′) arranged so as to allow insertion of the connector between the forks and provide guidance for each trunnion (212, 212′) of the connector by each fork (310, 310′). This embodiment facilitates placement and locking of the connector in the determined position. The shape of the recess (311, 311′) of each fork (310, 310′) is advantageously complementary to the recess in the trunnion (212, 212′) of the connector, in order to further limit displacements of the connector. The bottom of the recess (311, 311′) may limit vertical displacements of the connector.
The guide means (310, 310′) is advantageously mobile. It may optionally be provided with an elastic return means for bringing it back into an equilibrium position. The mobility of the guide means assures that the locking system has some flexibility when a connector is being inserted in the handling device and thus avoids possible degradation of elements of the system. It also overcomes some differences in the size of the connectors.
The recesses (311, 311′, 314, 314′), if any, advantageously form an opening (305, 305′) preventing a trunnion (212, 212′) from moving sideways out of the connector.
The means (315, 315′) of causing displacement of the mobile member or each mobile member (312, 312′) from the closed position to the open position advantageously includes at least one cam formed on the mobile member and configured such that it can cooperate with the hooks (10, 10′) (and more precisely with the ends (12, 12′) of the hooks) so as to cause displacement of the mobile member or each mobile member (312, 312′) from the closed position to the open position by a relative movement between the handling device (300) and the attachment hooks (10, 10′). The simplicity of this embodiment makes the handling device very reliable. The means (315, 315′) may optionally be a mechanical, pneumatic or electromechanical controlled means.
A particularly advantageous connector (200) suitable for use in the present invention advantageously comprises two levers (201, 202), two side trunnions (212, 212′), a tightening screw (210), and also at least one gripping device (231, 232) capable of cooperating with the locking system (310, 310′, 320) of the handling device so as to lock the connector in a desired position, called the normal handling position. In one advantageous embodiment of the invention, the two levers (201, 202) each comprise a cross-piece (203, 204) and the gripping means is a projecting rim (231, 232) provided on at least one of the cross-pieces (203, 204). This connector (200) can be handled by the handling device (300) according to the invention.
Operation of the handling device system (300) according to the present invention is illustrated using the particular example in
The example illustrated in
The example illustrated in
List of Numeric Marks
Additional advantages, features and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative devices, shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
All documents referred to herein are specifically incorporated herein by reference in their entireties.
As used herein and in the following claims, articles such as “the”, “a” and “an” can connote the singular or plural.
| Number | Date | Country | Kind |
|---|---|---|---|
| 03 05679 | May 2003 | FR | national |
| PCT/FR04/01131 | May 2004 | WO | international |
The present application is a continuation of International Application No. PCT/FR2004/001131 filed May 10, 2004, the content of which is incorporated herein by reference in its entirety.
