Patent Application
20240175158
The present invention relates to anode replacement and other operations of electrolytic cells in an aluminium production plant and in particular to a system and methods for handling anodes of aluminium production electrolytic cells.
Aluminium is produced industrially by smelting using the Hall-Héroult process which involves dissolving alumina (aluminium oxide) in an electrolyte bath consisting of molten cryolite to produce 99.5-99.8% pure aluminium.
The electrolysis process is conducted in a purpose-built cell called a pot. Typically, the pot is made of steel with an insulating lining of refractory materials. A cathode is located at the inner base of the pot. An anode in the form of a carbon rod or block is suspended in the electrolyte in the pot and oxide ions from dissolved alumina are discharged onto the anode. Aluminium is formed from the aluminium anions being reduced at the electrolyte/aluminium interface. The molten aluminium formed sinks below the electrolyte to the bottom of the pot.
Aluminium smelters consist of a large number of pots (cells) in a pot room in which the electrolysis takes place. A typical smelter contains hundreds of pots. The pots are connected in series with a cathode of one pot electrically connected to the next pot to form a potline. The process is operated as a batch process with the aluminium metal deposited at the bottom of the pots and periodically siphoned off. The electrolysis process requires large amount of electricity with a potline requiring an amperage of between 150 kA to 500 kA to keep the electrolyte bath at an operating temperature of around 950° C. and to generate the alumina reduction reaction.
The working environment around the potlines can be hazardous to personnel with a high ambient temperature due to the heat emitted from the cells. In addition, operators may be exposed to gaseous emissions and harmful particulates. The gaseous emissions produced during the process include gaseous hydrogen fluoride, with sodium fluoride, aluminium fluoride, sulphur dioxide, carbon dioxide and unused particulates of cryolite. This may be complicated by gaseous emissions such as sulphur dioxide and hydrogen fluoride reacting with moisture in the pot room and forming acids.
Over time the oxide ions react with the anode and gradually consumes the carbon anode forming gaseous carbon dioxide (CO2) and the consumed anode must be replaced. Regular anode replacement is needed to allow aluminium production to continue.
The anodes are heavy and bulky which makes it difficult for personnel to lift, handle and position accurately. This can result in collision of the anode with personnel and pot equipment.
Personnel are also exposed to the risk of falling in the pot, toxic gas emissions, harmful particulates, and high temperatures during regular anode replacement operations. The personnel may also be injured by manhandling heavy anodes and equipment. The close proximity to an uncovered pot may expose the operators to splashes or sprays of molten cryolite. The pot room personnel may also be exposed to a risk of electrocution if the anode is misaligned or not replaced correctly.
It is an object of an aspect of the present invention to provide a pot maintenance system capable of safely and accurately handling components pot during aluminium production.
It is another object of an aspect of the present invention to provide an anode handling system capable of safely and accurately handling and positioning anodes during aluminium production.
It is a further object of at least one aspect of the present invention to provide an anode handling system and method which allows the safe removal of expired anodes and replacement of new anodes quickly and accurately.
It is another object of an aspect of the present invention to provide a pot maintenance system capable of conducting anode handling operations reliably, autonomously and to a high degree of accuracy.
Further aims and objects of the invention will become apparent from reading the following description.
According to a first aspect of the invention, there is provided an anode replacement system for electrolytic cells of an aluminium production plant, the system comprising:
An anode assembly may comprise an anode block and a shaft. The sensor system may be configured to generate or collect position information to control the position of at least one anode assembly, anode block and/or anode shaft. The sensor system may be configured to generate or collect position information to control the position of the at least one movable member.
The system may comprise a control system configured to move the support frame, the at least one movable member, the at least one anode gripping apparatus and/or the position of the at least one anode assembly. The at least one movable member may be at least one telescopic member. The at least one movable member may be a robot assembly.
The at least one anode gripping apparatus may be configured to contact at least two surfaces or sides of the shaft. The at least one anode gripping apparatus may be configured to contact at least two surfaces or sides of the shaft to grip the shaft and prevent or mitigate the at least one anode assembly from swinging during an anode removal or replacement operation. The at least one anode gripping apparatus may be configured to grip the shaft by clamping the shaft. The at least one anode gripping apparatus may be configured to grip the shaft by clamping the shaft at any point or location along the length of the shaft. The at least one anode gripping apparatus may be configured to contact at least two surfaces or sides of the shaft to clamp the shaft. The at least one anode gripping apparatus may be configured to apply or exert opposing forces on two or more surfaces or sides of the shaft. The at least one anode gripping apparatus may be configured move at least two surfaces toward each other to exert opposing forces on the shaft. The at least one anode gripping apparatus may be configured to engage at least one aperture on the shaft. The at least one anode gripping apparatus may comprise at least one pin. The at least one anode gripping apparatus may be configured to engage at least pin hole on the shaft. The at least one anode gripping apparatus may comprise at least one pin configured to engage at least pin hole on the shaft. The at least one anode gripping apparatus may be configured to lock the shaft, straighten the shaft and/or reduce swing. The at least one anode gripping apparatus may be configured to engage at least two positions on the shaft of the at least one anode assembly. The at least one anode gripping apparatus may be configured to engage at least one pin hole or aperture on the shaft as a first position. The at least one anode gripping apparatus may be configured to grip the shaft as a second position. The at least one anode gripping apparatus may be configured to apply or exert opposing forces on two or more surfaces or sides of the shaft at any position on the shaft as a second position.
The at least one anode gripping apparatus may be configured to grip and/or clamp the shaft of the at least one anode assembly at a position close and/or adjacent to the anode block. This may facilitate the at least one anode assembly to be held securely and stably and to be moved to and from an electrolytic bath quickly and safely. Gripping the shaft of the anode assembly at a position close and/or adjacent to the anode block may assist in the precise movement and accurate positioning of the at least one anode assembly in the molten bath. The at least one anode gripping apparatus may be configured to at least partially surround a section of the shaft of an anode assembly to grip the shaft of an anode assembly. The at least one anode gripping apparatus may be configured to at least partially surround an outer surface of a section of the shaft of an anode assembly to grip the shaft of an anode assembly. The at least one anode gripping apparatus may be configured to apply a grip force to opposing sides of an anode shaft. The at least one anode assembly may be a spent anode and/or a replacement anode. The at least one anode gripping apparatus may comprise at least one grip member. The at least one grip member may be operable to move between an open condition and a closed condition. The at least one grip member may be operable to move to a closed condition to grip at least one shaft of an anode assembly. The at least one grip member may be operable to move to an open condition to release at least one shaft of an anode assembly. The at least one grip member may be a clamp member or a jaw member. The at least one grip member may be configured to be a failsafe closed grip member. The at least one grip member may be configured to move to or remain in a closed condition in the event of a loss of power, drive and/or loss of control signal. The at least one anode gripping apparatus may comprise two or more engaging surfaces. The at least one anode gripping apparatus may comprise two or more grip members. Where the at least one anode gripping apparatus comprises two or more engaging surfaces, they may be located on the grip members. The at least one anode gripping apparatus may comprise two or more jaw or clamp members. Where the at least one anode gripping apparatus comprises two or more engaging surfaces, they may be located on the jaw or clamp members.
The at least one anode gripping apparatus may comprise one or more jaw members. The at least one jaw member may be operable to move between an open condition and a closed condition. The at least one jaw member may be operable to move to a closed condition to grip a shaft of an anode. The at least one jaw member may be operable to move to an open condition to release a shaft of an anode. The at least one anode gripping apparatus comprises two or more jaw members. At least one of the two or more jaws may be operable to move between an open condition and a closed condition. The at least one of the two or more jaws may be operable to move to a closed condition to grip a shaft of an anode. The at least one of the two or more jaws may be operable to move to an open condition to release a shaft of an anode.
The system may comprise at least one lid maintenance functional module. The system may comprise a lid gripping apparatus comprising one or more jaw members configured to grip a section or part of one or more pot lids. The lid gripping apparatus may be configured to grip a lid handle. The system may comprise at least one alumina powder dispenser.
The system may comprise at least one crust maintenance functional module. The at least one crust maintenance functional module may be scoop apparatus and/or a crust breaker apparatus. The at least one crust maintenance functional module may comprise a device configure to collect or sweep material and/or debris from the electrolytic cell, for example spills of alumina powder or molten cryolite. The at least one crust maintenance functional module may be one or more crust breaker apparatus configured to break the crust of solidified cryolite. The solidified cryolite may surround one or more anodes to be removed. The at least one crust maintenance functional module may comprise one or more scoop apparatus configured to scoop or remove debris such as crust fragments from the molten electrolytic bath.
The support frame may be a movable support. The support frame may be a positioning system. The positioning system may be supported by a crane. The system may be configured to be vertically and/or horizontally movable on a support. The support may be a stationary or a mobile support. The support may be a vehicle and/or a component of a vehicle. The support may be a crane and/or a component of a crane. The support may be an overhead crane. The support frame may be mounted to a crane and/or a vehicle.
The system may be configured to be movably mounted on a support by one or more springs. The system may be mounted on a support by a spring suspension system. The spring suspension system may comprise one or more rigid or stiff springs. The spring suspension system may comprise one or more shock absorbers. The spring suspension system may be configured to minimise or mitigate forces acting on the at least one anode gripper apparatus being transferred to the support. The spring suspension system may be configured to minimise or mitigate forces acting on the support being transferred to the at least one anode gripper apparatus.
The support may have a longitudinal axis. A first positioning member may be movably mounted on the support. The first positioning member may comprise a first axis and a second axis. The first positioning member may be configured to move along the longitudinal axis of the support with the first axis parallel to the longitudinal axis of the support. A second positioning member may be mounted to the first positioning member. The second positioning member may be configured to move transversely to the first axis of the first positioning member.
The second positioning member may be configured to move substantially perpendicularly to the first axis of the first positioning member, which may be the second axis of the first positioning member. The second positioning member may therefore be configured to move transversely to the longitudinal axis of the support.
The first positioning member may be moved along the longitudinal axis of the support by one or more mechanisms configured to slide, push and/or pull the first positioning member. The second position member may be moved transversely to the first axis of the first positioning member by one or more mechanisms configured to slide, push and/or pull the second positioning member.
The at least one movable member may be a telescopic member. The at least one movable member may be configured to move between an extended condition and a retracted condition. The anode replacement system may comprise at least one drive mechanism. The at least one drive mechanism may comprise at least one rack and pinion drive mechanism. The anode replacement system may comprise a drive mechanism for the least one movable member. The anode replacement system may comprise a drive mechanism for each of the movable components of the positioning system including the position system support, first positioning member and/or second positioning member. The at least one drive mechanism may comprise at least one drive means. The at least one drive means may be configured to move the at least one movable member, position system support, the first positioning member and/or the second positioning member. The at least one drive means may be hydraulic, pneumatic and/or electric system. The at least one drive means may be a combination of hydraulic, pneumatic and/or electric systems. The at least one drive means may comprise one or more motors. The one or more motors may comprise one or more electric motors. The one or more motors may comprise one or more servomotors.
The at least one drive means may be configured to move the at least one movable member, position system support, the first positioning member and/or the second positioning member within an accuracy of between 0.5 mm to 10 mm. The at least one drive means may be configured to move the at least one movable member, position system support, the first positioning member and/or the second positioning member within an accuracy of between 1 mm to 5 mm. The at least one drive means may be configured to move the at least one movable member, position system support, the first positioning member and/or the second positioning member within an accuracy +/−1 mm.
The sensor system may comprise at least one sensor. The at least one sensor may be located on the support frame, at least one movable member, at least one anode gripping apparatus and/or at least one functional module. The at least one sensor may be located on the pot and/or a component of the pot. The at least one sensor may be located on at least one anode. The at least one sensor may be located in the pot room and/or on a potline. the at least one sensor may be mounted or positioned on components of the positioning system such as the support, first positioning member or second positioning member. The at least one sensor may be located or mounted on a component of a crane or vehicle. The at least one sensor may be located or mounted on a component of a surrounding structure such as a floor, walls and/or roof. The support frame may be movably mounted on a support, vehicle, crane, positioning system or at least one positioning member of a positioning system. The support, vehicle, crane, positioning system, or positioning member may comprise a plurality of positional markers. The plurality of positional markers may be selected from the group comprising barcodes, data matrix codes, quick response codes and/or colour codes.
The sensor system may be configured to detect at least one of the plurality of positional markers to accurately locate and/or move the position of the support, vehicle, crane, positioning system and/or at least one positioning member. The at least one sensor may be selected from the group comprising: optical sensor, camera, vision system, time of flight camera, depth sensor, distance sensor, laser, ultrasound, momentum sensor, accelerometer, rotary position sensor, gyroscopic position sensor, global positioning sensor, infra-red sensor, thermal sensor, load cell and/or LIDAR.
The system may comprise at least one processing unit. The sensor system may be connected to at least one processing unit. The system may comprise at least one control unit. The sensor system and/or the at least one processing unit may be connected to at least one control unit.
The sensor system may be configured to generate 2D and/or 3D position information of a pot, a pot lid, a lid handle, a lid step, anode assemblies in a pot; an anode assembly to be replaced, a replacement anode assembly, one or more anode shafts; a potline, components in a pot room and/or a part of the pot room. The sensor system may be configured to generate 2D and/or 3D position information of potential obstacles and/or personnel in a work area surrounding a pot of interest. The sensor system may be configured to generate 2D and/or 3D position information of components of the anode replacement system in relation to the pot, a potline, a pot room and/or a part of the pot room. The sensor system may be configured to generate 2D and/or 3D position information of components of crane, vehicle, positioning system, first positioning member, second positioning member, support frame, at least one movable member, at least one anode gripping apparatus and/or at least one functional module. The sensor system may be configured to generate 2D and/or 3D position information of a replacement anode storage area and a spent anode storage area.
The sensor system may be configured to identify the position of a specific anode assembly in the pot room. The sensor system may be configured to inspect the status or condition of one or more specific anode assembly. The sensor system may be operable to generate information of the position of the support, first positioning member and/or second positioning member in relation to the at least one movable member and/or at least one anode gripping apparatus. The sensor system may be configured to communicate the position information to at least one processing unit. The at least one processing unit may be configured to process a movement path for the anode replacement system. The at least one processing unit may be configured to process a movement path for the crane, vehicle, positioning system, first positioning member, second positioning member, support frame, at least one movable member, at least one anode gripping apparatus a gripped anode assembly, and/or at least one functional module. The at least one processing unit may be configured to process a movement path based on the position information generated by the sensor system. The sensor system may be configured to monitor the movement of the crane, vehicle, positioning system, first positioning member, second positioning member, support frame, at least one movable member, at least one anode gripping apparatus; a gripped anode assembly, and/or at least one functional module to prevent a collision in the work area surrounding the pot.
The position information may comprise at least one of a position of a crane, vehicle, positioning system, first positioning member, second positioning member, support frame, at least one movable member, at least one anode gripping apparatus, a gripped anode assembly and/or at least one functional module.
The system may comprise at least one control unit configured to move the crane, vehicle, positioning system, first positioning member, second positioning member, support frame, at least one movable member, at least one anode gripping apparatus, at least one functional module in relation to the pot, lid and/or anode. The sensor system may be configured to monitor the position information to prevent a collision in the work area surrounding the pot.
The sensor system may be configured to generate position information to identify at least one object in the work environment to position the at least one functional module to the perform one or more tasks on or with the object. The sensor system may comprise a vision system. The vision system may be configured to obtain accurate positional data on components of the anode replacement system, at least one movable member, at least one anode gripping apparatus and/or their surrounding environment. The vision system may be configured to generate 2D and/or 3D position information. The vision system may comprise at least one sensor. The at least one vision system sensor may be selected from the group comprising an optical sensor, camera, time of flight camera, depth sensor, distance sensor and/or a laser. The vision system may comprise at least one camera. Preferably the vision system comprises at least one time of flight camera.
The anode gripper apparatus may be configured to position a replacement anode assembly at an optimal position in the pot using data from the sensor system and/or the vision system. The vision system of the sensor system may be configured to track a marking or position on a spent anode in relation to a marking or position on a pot structure. The vision system of the sensor system may be configured to track and/or measure the height of the anode block of a spent anode when removed from the pot. The anode gripper apparatus may comprise one or more mechanisms to adjust the tilt angle of the anode gripper apparatus and/or to adjust the adjust the vertical position height of an attached anode assembly.
The sensor system may comprise a plurality of sensors. The sensor system, at least one processing unit and at least one control unit may be part of a guidance, navigation and control system for positioning and controlling the anode replacement system.
The system may be an autonomous system. The system may be an automated system. The system may be a semi-autonomous system or semi-automated system. The system may be controlled by a user controlling remote manipulators.
According to a second aspect of the invention, there is provided an anode replacement system for electrolytic cells of an aluminium production plant, the system comprising:
The anode replacement system may comprise at least one crust maintenance functional module and/or at least one lid maintenance functional module. The at least one lid maintenance functional module may be a lid gripping apparatus. The at least one crust maintenance functional module may be a scoop apparatus and/or a crust breaker apparatus.
The anode replacement system may comprise at least one grip member. The anode replacement system may comprise two or more movable members. The at least one anode gripper apparatus and the at least one crust maintenance functional module may be mounted on the same or different movable members.
Embodiments of the second aspect of the invention may include one or more features of the first aspect of the invention or its embodiments, or vice versa.
According to a third aspect of the invention, there is provided an anode gripping apparatus handling for handling anodes in an aluminium production plant comprising:
The at least one grip member may be configured to be movable between an open condition and a closed condition. The at least one grip member may be configured to grip a shaft of at least one anode assembly at any position along the shaft of the at least one anode assembly.
The at least one grip member may be operable to grip at least one shaft of an anode assembly. The anode gripper apparatus may comprise at least one actuator configured to move the at least one grip member between an open condition and a closed condition. The least one actuator may be an electrical, hydraulic, or pneumatic actuator. The anode gripper apparatus may be configured to be movably mounted on a movable member of an anode replacement system. The anode gripper apparatus may be configured to be movably mounted on a telescopic member.
The at least one grip member may be configured to grip a part of or a section of an anode shaft when in a closed position. The at least one anode gripping apparatus may be configured to surround or at least partially surround a section of the shaft of an anode assembly to grip the shaft of an anode assembly. The at least one anode gripping apparatus is configured to apply a grip force to opposing sides of an anode shaft when in a grip condition. The at least one grip member may be configured to grip a part of or a section of an anode shaft at an anode clamp position. The at least one grip member may be configured to grip a part of or a section of an anode shaft at close proximity to an anode clamp position. By gripping the anode at a position on the shaft at or close to the anode clamp position the anode shaft may be held securely and positioned accurately until it is clamped into place on the pot. The anode gripper apparatus may comprise two or more grip members. The at least one grip member may be a jaw member.
The anode gripper apparatus may comprise at least one sensor. The at least one sensor may be mounted on the support frame of the anode gripper apparatus. The at least one sensor may be mounted on at least one movable member on which the anode gripper apparatus is mounted. The at least one sensor may be configured to measure the height of an anode assembly, an anode block and/or an anode shaft. The at least one sensor may be configured to measure, calculate, or estimate a distance between an upper surface of a cathode in the pot and a lower surface of a spent anode in the pot.
The anode gripper apparatus may be configured to position a replacement anode at a desired or optimal distance between an upper surface of a cathode in the pot and a lower surface of a replacement anode in a pot. The desired or optimal distance of the lower surface of the replacement anode to the upper surface of the cathode may be equal to the distance of lower surface of the spent anode to the upper surface of the cathode.
The anode gripper apparatus may be configured to position a replacement anode at a vertical offset in the bath. The vertical offset may be a distance the anode is raised from a desired, calculated, or optimal distance in the bath. The desired, calculated, or optimal distance may be a distance between an upper surface of the cathode and a lower surface of a spent anode block. The vertical offset may be used to mitigate shock heating of the replacement anode. Locating the replacement anode at a vertical offset may extend the lifespan of the replacement anode. The offset may be within an offset range which may be within a range of +/−5 mm to +/−30 mm. The offset range may be approximately +/−20 mm. The vertical offset may be within a range of 5 mm to 30 mm above the desired, calculated, or optimal distance in the bath. Preferably the vertical offset is 10 mm.
The anode gripper apparatus may be configured to position the replacement anode at the desired or optimal distance using feedback from the at least one sensor. The at least one sensor and at least one processing unit may be configured to measure, calculate and/or determine a desired vertical offset for a replacement anode assembly.
The at least one sensor may be configured to track a marking or position on a spent anode in relation to a marking or position on a pot structure. The at least one sensor may be configured to track and/or measure the height of the anode block of a spent anode when removed from the pot. The sensor system may reference the distance from a marking or position on the spent anode to the bottom of the anode assembly.
The at least one sensor in the sensor system may be configured to measure and/or track at least one position data point of the replacement anode. The at least one position data point may be a shaft position in the X, Y, and/or Z axes. The at least one position data point may be a position of a surface of the replacement anode with respect to the height of the molten electrolyte. The at least one position data point may be position of the end of the anode shaft of the replacement anode with respect to the height of the molten electrolyte.
The anode gripper apparatus may comprise one or more mechanisms to control tilt adjustment to adjust the angle of the anode gripper apparatus and/or to adjust the angle of a connected anode relative to a horizontally and/or vertical plane. The anode gripper apparatus may comprise one or more mechanisms to adjust the tilt angle of the anode gripper apparatus. The anode gripper apparatus may comprise one or more mechanisms to adjust the adjust the vertical position height of an attached anode assembly. The one or more mechanisms may comprise a piston. The anode gripper apparatus may comprise one or more mechanisms to adjust the vertical position of an anode clamped to the pot structure.
The anode gripper apparatus may comprise one or more mechanisms to control height adjustment. The one or more mechanisms may be configured to adjust the height of an anode within an adjustment range. The adjustment range may be a value from +/−5 mm to +/−100 mm. In one embodiment, the adjustment range may be a value from +/−20 mm to +/−40 mm. Optionally, a limit of the adjustment range may be approximately +/−30 mm. The one or more mechanisms may comprise a piston. The anode gripper apparatus may be configured to adjust the height and/or position of the anode assembly during installation of the anode assembly in the pot. The anode gripper apparatus may be configured to adjust the height and/or position of the anode assembly during clamping of the anode assembly in the pot. The anode gripper apparatus may be configured to adjust the height and/or position of the anode assembly after the anode assembly has been clamped to the pot structure. The anode gripper apparatus may be configured to adjust the height and/or position of the anode assembly in the pot in response to operation efficiency information of the pot and/or anode assembly in the pot. The anode gripper apparatus may be configured to adjust the height and/or position of one or more anode assembly in the pot to improve the operational efficiency of the pot.
The anode gripper apparatus may comprise at least one clamp locking member. The at least one clamp locking member may be configured to receive and/or hold one or more lugs of an anode clamp.
Embodiments of the third aspect of the invention may include one or more features of the first or second aspects of the invention or their embodiments, or vice versa.
According to a fourth aspect of the invention, there is provided a method of replacing an anode assembly in a pot in an aluminium production plant; the method comprising:
The method may comprise measuring and/or calculating a position of the spent anode assembly in the pot. The method may comprise verifying, using data acquired by the sensor system, that the replacement anode is located at a correct position, orientation and/or height in the pot bath.
The method may comprise measuring and/or calculating using data acquired by the sensor system a distance between a lower surface of the spent anode block and an upper surface of a cathode in the pot. The method may comprise locating a lower surface of replacement anode block at the same distance from the cathode as the distance between a lower surface of the spent anode block and an upper surface of a cathode in the pot.
The method may comprise generating position data for at least one anode and anode shaft in the pot using the vision system. The method may comprise generating position data for at least one anode and anode shaft in the pot using a camera system. The method may comprise generating position data for at least one anode and anode shaft in the pot using a TOF camera system.
The anode replacement system may comprise a support frame and at least one movable member mounted on the support frame wherein the at least one movable member supports the least one anode gripping apparatus.
The anode replacement system may be movably mounted on a crane. The anode replacement system may be movably mounted on a vehicle. The support frame may be movably mounted on an overhead crane. The method may comprise moving the overhead crane relative to the pot. The support frame may be mounted on a positioning member such as a trolley moveably mounted on an overhead crane.
The support frame may be movably mounted on a positioning system or a positioning member of a positioning system. The positioning system may be movably mounted on a crane or vehicle. The positioning system may comprise a support having a longitudinal axis. A first positioning member may be movably mounted on the support. The first positioning member may comprise a first axis and a second axis. The first positioning member may be configured to move along the longitudinal axis of the support with the first axis parallel to the longitudinal axis of the support. A second positioning member may be mounted to the first positioning member. The second positioning member may be configured to move transversely to the first axis of the first positioning member. The support frame may be movably mounted on the first or second positioning member.
The method may comprise detecting at least one positional marker to accurately locate and/or move the position of the support, first positioning member and/or a second positioning member. The method may comprise moving the first positioning member and/or a second positioning member to align with at least a second position positional marker to accurately relocate the position of the support frame and/or the anode replacement system.
The positional marker may be selected from the group comprising barcodes, data matrix codes, quick response (QR) codes and/or colour codes. The method may comprise using a sensor system to detect the at least one positional marker. The sensor system comprises at least one sensor selected from the group comprising optical sensor, camera, vision system, time of flight camera, depth sensor, distance sensor, laser, ultrasound, momentum sensor, accelerometer, rotary position sensor, gyroscopic position sensor, global positioning sensor, infra-red sensor, thermal sensor, load cell and/or LIDAR. The method may comprise generating position data for the crane, vehicle, support frame, positioning system, first positioning member, second positioning member, anode replacement system, at least one movable member and/or the least one anode gripping apparatus.
Embodiments of the fourth aspect of the invention may include one or more features of any of the first to third aspects of the invention or their embodiments, or vice versa.
According to a fifth aspect of the invention, there is provided a method of replacing an anode in a pot in an aluminium production plant; the method comprising: providing an anode handling system comprising;
The method may comprise positioning the replacement anode in the pot with a vertical offset of up to 20 mm above the vertical distance. The method may comprise positioning the replacement anode in the pot with a vertical offset of up to 10 mm above the vertical distance.
Embodiments of the fifth aspect of the invention may include one or more features of any of the first to fourth aspects of the invention or their embodiments, or vice versa.
According to a sixth aspect of the invention, there is provided a method for removing an anode assembly from a pot in an aluminium production plant; the method comprising:
The method may comprise moving the anode assembly from the pot to a spent anode storage area.
Embodiments of the sixth aspect of the invention may include one or more features of any of the first to fifth aspects of the invention or their embodiments, or vice versa.
According to a seventh aspect of the invention, there is provided a method of handling a replacement anode assembly in an aluminium production plant; the method comprising:
Embodiments of the seventh aspect of the invention may include one or more features of any of the first to sixth aspects of the invention or their embodiments, or vice versa.
According to an eighth aspect of the invention, there is provided a method of adjusting a position of an anode in a pot of an aluminium production plant; the method comprising:
The anode assembly may be an existing anode assembly installed in the pot. The anode assembly may be a replacement anode assembly being installed in the pot.
The method may comprise adjusting the height and/or position of the anode assembly in the pot in response to operation efficiency information of the pot and/or anode assembly in the pot. The method may comprise adjusting the height and/or position of one or more anode assembly in the pot to improve the operational efficiency of the pot.
Embodiments of the eighth aspect of the invention may include one or more features of any of the first to seventh aspects of the invention or their embodiments, or vice versa.
According to a ninth aspect of the invention, there is provided a method of adjusting an orientation of anode in a pot of an aluminium production plant; the method comprising: providing an anode replacement system comprising;
The method may comprise adjusting the orientation of a replacement anode assembly gripped by the at least one anode gripper apparatus.
The method may comprise adjusting the orientation of an anode assembly present in the pot. The at least one anode gripper apparatus may be configured to grip a shaft of the anode assembly present in the pot to locate the anode in a desired orientation.
Embodiments of the ninth aspect of the invention may include one or more features of any of the first to eighth aspects of the invention or their embodiments, or vice versa.
According to a tenth aspect of the invention, there is provided a system for maintenance of pots of an aluminium production plant, the system comprising:
Embodiments of the tenth aspect of the invention may include one or more features of any of the first to ninth aspects of the invention or their embodiments, or vice versa.
There will now be described, by way of example only, various embodiments of the invention with reference to the drawings, of which:
Aluminium production plants comprise several pot rooms each housing hundreds of pots which are arranged in series into potlines. The pot 10 comprises a steel tank 12 with insulating lining 16 made of heat resistance materials. A cathode (not shown) is located at the inner base of the pot. The surface of the lining material and the cathode from a crucible 14 in the pot where an electrolytic bath containing electrolyte consisting of molten cryolite is used to dissolve alumina during aluminium production.
As best shown in
The support shaft 24 has aperture 26 at the distal end which is conventional designed to engage a hook to allow pot room personnel to pull the anode out of the pot. In this example the support shaft 24 is made of copper. The anode assembly 18 is removably secured to the pot support structure 20 by an anode clamp hooks 28 engaging an anode clamp 40. The clamp is configured to allow gradual longitudinal movement of the rod and anode in a generally downward direction in order to maintain efficiency of the electrolytic process.
The clamp 28 is configured to secure the support shaft 24 to hold the anode assembly 18 at a predetermined height in the electrolytic bath. In order to maintain efficiency of the electrolytic process it is important that the distance or height between a lower surface of the anode and an upper surface of the cathode is maintained. The anode clamp also prevents lateral movement of the support shaft 24 and anode block 22. The clamp makes an electrical connection between the clamped anode and the pot structure 20.
During the electrolytic process oxide ions from the alumina react with the carbon anode block and gradually consume the carbon anode block forming gaseous carbon dioxide (CO2) in the process. As the carbon anode blocks 22 are gradually consumed the carbon anode blocks 22 are gradually lowered into the crucible 14 to maintain the exposure of the anode assembly 18 to the electrolytic bath.
Once consumed the anode assembly 18 is required to be replaced to allow aluminium production to continue. The anodes in the pot are replaced at different times and therefore are in operation for different durations resulting in a different degree of consumption for each spent anode. The height at which a replacement anode should be suspended may be different for each anode in the pot. The accurate positioning of a replacement anode is crucial to maintain the efficiency of the electrolytic process as the height of each removed spent anode may be different.
The position of the replacement anode and degree of immersion in the electrolytic bath must be adjusted every time such that the height of the lower surface of the replacement carbon anode from the cathode must be the same as the height of the lower surface of the expired carbon anode from the cathode. The lower surface of the replacement carbon anode may also be parallel with the cathode to ensure efficient electrolytic reaction.
The two support beams 114a, 114b act as crane bridge girders and form a crane bridge which is movably mounted on support rails 119 forming an overhead crane 120.
The overhead crane 120 has two parallel runway beams 122a and 122b on which rails 119 are mounted. The runway beams 122a and 122b support the movable support apparatus 110 to which the anode handling system 200 is attached. In this example the runway beams form part of the building structure. However, alternatively the runway beams 122a and 122b may be mounted on movable supports or stationary supports.
The positioning apparatus 110 has cross beams 118a, 118b at each end of the support beams 114a, 114b. Rail wheels 130 are mounted on the cross beams 118a, 118b and are configured to engage the rail 119 on the runway beams 122a and 122b. Actuation of motors 117a move the rail wheels 130 to move the positioning apparatus along the longitudinal length of the runway beams 122a and 122b. A plurality of positional markers such as QR codes 113 are arranged at known positions along the longitudinal length of the runway beam 122a. A camera system 111 captures image data of the QR codes to accurately locate the position of the positioning system 110 along the longitudinal length of the runway beams 122a and 122b.
The positioning apparatus has a trolley 116 movably mounted relative to the support beams 114a, 114b. The support beams 114a, 114b have a longitudinal guide 132 located on an upper surface 115 of the support beams 114a, 114b. The longitudinal guide 132 spans the longitudinal length of the support beams 114a, 114b. In this example the longitudinal guide 120 is a toothed rack 131. A plurality of positional markers such as QR codes 113a are arranged at known positions along the longitudinal length of the support beams 114b. The camera system 111 captures image data of the QR codes 113a to accurately locate the position of the trolley along the longitudinal length of the support beam 114b. The trolley 116 has a trolley frame 140 comprising two girder supports 142a, 142b and two drive supports 144a, 144b. The two drive supports 144a, 144b are connected to the supports 142a, 142b as end supports with the drive supports 144a, 144b arranged parallel with the frame support beams 114a, 114b.
The two supports 142a, 142b span the distance between the substantially parallel support beams 114a, 114b. Each of the two drive supports 144a, 144b have two pinion gears 148 at each end. The pinion gears 148 are rotatably mounted on the drive supports 144a, 144b. The trolley frame 140 supports reversible motors 143 connected to each pinion gear 148. Each pinion gear 148 has teeth 149 which cooperate with teeth 131b on the rack 131 such that when the motor rotates the pinion gear 148 the pinion travels along the rack which moves the first trolley 116 along the support beams 114a, 114b shown as arrow “F” in
The motors 143 are connected to a control unit 614 (discussed further in relation to
The trolley 116 supports a second trolley also known as a travelling carriage 150. Each of the supports 142a, 142b of the trolley frame 140 has a longitudinal guide 141 located on an upper surface of the support beams 142a, 142b. The longitudinal guide 141 spans the longitudinal length of the supports 142a, 142b. In this example the longitudinal guide 141 is a rack. A plurality of QR code positional markers 113b are arranged at known positions along the longitudinal length of a support beam 142a. The camera system 111 captures image data of the positional markers to accurately locate the position of the second trolley 150 along the longitudinal length of the support beam 142a, 142b.
The second trolley 150 has a base 152 made of steel plate with edges 152a, 152b, 152c and 152d. Opposing edges 152a and 152b span the distance between the parallel supports 142a, 142b of the trolley 116. Pinion gears 154 are rotatably mounted at each end of the opposing edges 152c and 152d. The second trolley 150 supports motors 137 connected to each pinion gear 154. Each pinion gear 154 has teeth which cooperate with teeth on the rack 141 such that when the motor rotates the pinion gear 154 the pinion travels along the rack which moves the second trolley 150 along the supports 142a, 142b of the trolley frame 140 shown as arrows “H” in
The pinion gears 154 support the weight of the second trolley 150 and assist in transferring loads or forces acting on second trolley 150 to supports 114a, 114b of the apparatus.
The second trolley motor 137 is connected to a control unit 614 (discussed further in relation to
A rotatable platform 160 is rotatably mounted on base 152 of the second trolley 150. The rotatable platform 160 is supported by gearing assembly. A drive assembly (not shown) is configured to rotate the platform. The anode handling system 200 is attached to the rotatable platform 160. The rotatable platform 160 acts as turntable enabling the anode handling system best shown in
The control unit uses data from the camera system 111 to allow accurate movement and positioning of the positioning system, first trolley and/or second trolley within 1 mm accuracy.
The movable support apparatus provides movement of the base 152 in two different axes. This may provide the lifting apparatus with precision movement and alignment in two axes. This allows the anode handling system connected to the platform 160 to be located at high accuracy in two axes. The trolley 116 is movable to any position along the longitudinal length the support beams 114a, 114b. The second trolley 150 is movable to any position along the longitudinal length of supports 142a, 142b of the trolley frame 140.
The positioning apparatus is configured to moveable independently along the X and/or Y axis. The X-axis may be defined by the longitudinal guide 132 on support beams 114a. 114b. The Y-axis may be defined by the longitudinal guide 141 on the supports 142a, 142b. The system is configured to move and position the anode handling system to a first precision by moving of the positioning apparatus 110 along the rails in parallel to the longitudinal direction of the rails 119. The system is configured to move and position the anode handling system to a second precision allowing fine positioning by moving the second trolley in a direction parallel to the longitudinal direction of the rails. The system allows fine control adjustment of the position of the anode handling system without requiring movement or repositioning of the entire crane and/or movement support apparatus.
The anode replacement system 200 has a central frame 210. An upper component 210a of the frame is mounted to a lower surface of the rotatable platform 160 via springs 263. In this example four springs 263 are mounted between the rotatable platform 160 and the upper component 210a, one spring at each corner of the upper component 210a. The springs act as a shock absorber in the event that a shock or impact is exerted on a component of the anode replacement system 200 is it absorbed by the springs 263 and not transmitted to the rotatable platform 160 or the components of the trolleys or crane. The frame may be moved 360 degrees about rotational axis shown as “A” in
The at least one pot maintenance functional module is designed to perform specific tasks in a pot maintenance operation. Each of the four telescopic members has at least one sensor 532, 534, 536, 538, in this example the sensor is a TOF camera configured to provide real time images and distance information between the camera and the subject for each point of the image. The camera data is received by a processing unit and control unit to allow the accurate control and movement of the telescopic members and the functional module.
In this example, each of the telescopic members 222, 224 support an anode gripper apparatus 310 which together with the telescopic member forms a separate anode handling system 300. Each anode gripper apparatus 310 mounted on telescopic members is capable of gripping, handling, and lifting an anode. In this example the anode replacement system 200 has two anode handling systems 300. It will be appreciated that in other embodiments the anode replacement system may have one or more anode replacement system.
Telescopic member 228 supports a crust breaker device 250. In this example the crust breaker device has a hydraulic cylinder with a reciprocating shaft which act as a crust breaking chisel or hammer 252. It will be appreciated that additional or alternatively electric or pneumatic actuators may be used. The chisel or hammer configured to penetrate or impact a crust that forms on an upper surface of the molten electrolyte. Telescopic member 226 supports a scoop 270. The scoop 270 is dimensioned to have the greater width than the anode. The scoop 270 has sides 272 with a curved base 274 forming a bucket. The curved base has a plurality of apertures 280 or slots dimensioned to retain solid material in the bucket such as crust fragments and solid alumina whilst allowing molten or liquid material to pass through the apertures and remain the bath. Once the crust has been broken and the anode removed the scoop removed solid materials from the bath and prevent any obstacles to the positioning of the replacement anode.
The anode gripper apparatus 310 has a frame 311 which is pivotally mounted to the telescopic member 224 by pivot 312. A first end of a piston 313 is pivotally mounted on the telescopic member 224 by pivot 312. A second end of piston 313 is pivotally mounted on the frame 311 by pivot 315. Actuation of the piston causes the frame to pivot about pivot 312 relative to the telescopic member. Extension of the piston pivots the frame in a generally downwards direction. Retraction of the piston pivots the frame relative to the telescopic member in a generally upwards direction. This provides the anode handling system with tilt and positioning control.
The apparatus 310 has two arms 314, 316. Arm 314 is pivotally mounted to the frame about pivot 318. Arm 316 is pivotally mounted to the frame about pivot 320. At a first end of arms 314, 316 are jaws members 322, 323. Each jaw member has a friction plates or pad 324 secured to an inner surface of the jaw members 322, 323 to assist in gripping an anode shaft.
A compression spring 326 is mounted between the second end of arms 314, 316 and is configured to apply a moment to arm 314 in clockwise direction relative to the frame about pivot 318 and apply a moment to arm 316 in an anti-clockwise direction relative to the frame about pivot 332 to pivot the jaws members 322, 323 towards one another shown in
The anode gripper apparatus 310 has two clamp support arms 330, 332 configured to engage and secure an anode clamp 40 against the anode shaft 24 best shown in
Lock member 344 is attached to piston 350 and lock member 346 is attached to piston 352. When the piston 350 is retracted the locking member 344 is rotated about pivot 362 to a closed position and the lug 40b is locked in the lock member 344. When the piston 352 is extended the locking member 346 is rotated about pivot 364 to a closed position where the aperture 348 is covered and the lug 40a is locked in the lock member 346. In order to release the anode clamp 40 from the clamp support arms 330 and 332, piston 350 is extended to rotate the lock member 344 approximately ninety degrees in a clockwise direction about pivot 362. Piston 352 is retracted to rotate the lock member 346 ninety degrees in an anti-clockwise direction about pivot 364. The apertures in the front wall of the lock members 244 and 246 are aligned allowing lugs of the anode clamp to pass through.
In this example the compression spring 326 and piston 328 are configured in a failsafe closed arrangement. The support arms 314, 316 are maintained in a jaw closed or grip position in the event of a loss of power, pneumatics, hydraulic and/or a control signal is interrupted or lost. This means that a gripped anode would not be released or dropped in the event of a loss of power, pneumatics, hydraulic and/or a control signal. This may mitigate risks to personnel and infrastructure from anodes being accidently released and falling on personnel, into pots or onto infrastructure due to a loss power, pneumatics, hydraulic and/or a control signal.
The system may be an automated or autonomous system. The system comprises a sensor system that identify tasks to be performed and provide relative position information for components of the anode replacement system in the pot maintenance system and objects in the pot room. One or more processors in the system process the sensor data to produced relative navigation instructions for movement and actuation instructions of the components of the anode replacement system to perform the tasks. The system has a control system to move and actuate the components of the anode replacement system according to the processor instructions to perform the tasks. The sensor system monitors the operation of the anode replacement system to verify that a task is performed to a predetermined standard or whether it needs to be repeated or amended.
The system 600 has a sensor system 610 configured to capture image data of positional markers located at known positions on the crane, positioning apparatus, the first trolley and/or the second trolley. In this example a camera 111 is used to identify QR codes that are located along the longitudinal length of runway beam 122a, support beam 114b and support beam 142a.
Optionally, components of the pot room including equipment, pots, anode assemblies and/or lids may comprise one or more positional markers such as QR codes to assist in the sensor system accurately positioning the anode replacement system in the pot room or relative to selected pots, anode assemblies and/or pot lids. This may also assist in the sensor system identifying and moving around known obstacles in the workspace.
The system 600 has a processing unit 612 and a programmable logic controller (PLC) 614. The processing unit 612 receives the captured QR image data from the camera system 610. The processing unit 612 identifies the QR code as a specific location of the crane, positioning system, first trolley and/or second trolley.
To locate the anode replacement system 200 attached to the second trolley at position adjacent to a specific anode to be replaced, the sensor system 600 locates the positioning system at a desired position on the crane. The processing unit identifies the corresponding QR code associated with the new location on the crane. The PLC 614 controls the motors 117a to move the positioning apparatus along the longitudinal length of runway beam 122a to reach the new location on the runway beam 122a of the crane. Optionally the processing unit uses real time feedback from the camera system 111 to confirm the positioning apparatus is located at the correct position on the runway beam 122a using captured QR code data.
The system 600 then locates the first trolley 116 at a desired position on the positioning apparatus. The processing unit 110 identifies the corresponding QR code associated with the new location on the positioning apparatus. The PLC controls the motors 143 to move the first trolley along the longitudinal length of support beams 114a, 114b to reach the new location on the support beams 114a, 114b of the positioning apparatus. Optionally the processing unit uses real time feedback from the camera system 111 to confirm that the first trolley 116 is located at the correct position on the support beams 114a, 114b using captured QR code data.
If a second trolley is present, optionally the system 600 then locates the second trolley at a desired position on the first trolley. The processing unit identifies the corresponding QR code associated with the new location on the first trolley. The PLC controls the motors 137 to move the second trolley along the longitudinal length of support beams 142a, 142b to reach the desired location on the support beams 142a, 142b of the first trolley. Optionally the processing unit uses real time feedback from the camera system 111 to confirm that the second trolley 116 is located at the correct position on the support beam 142a and that the anode replacement system 200 is located adjacent to a desired anode location using captured QR code data. Although the movement of the positioning system, first trolley and/or second trolley are described as a sequential movement it will be appreciated that the sequence order may be different. It will also be appreciated that the movement of the positioning system, first trolley and/or second trolley may be simultaneous, synchronised or have overlapping action movements.
The system 600 has a vision system 620 configured to accurately obtain accurate positional data on components of the anode replacement system 200 and their surrounding environment. The vision system comprises at least one sensor. In this example time of flight (TOF) cameras are mounted on an individual telescopic member 370 on the anode replacement system and on a robot assembly of a lid handling system. Each TOF camera provide real time images and distance information between the camera and the subject for each point of the image. The processing unit 612 receives the positional data to allow the accurate control and movement of the telescopic members and the functional module.
Once the system 600 has located the anode replacement system 200 adjacent to an anode to be replaced. The TOF camera 532 mounted on telescopic member 228 obtains positional data on the position of the crust breaker device 250 relative to the crust surrounding the anode to be replaced. The processing unit uses real time positional data from the TOF camera 532 to issue signals to the PLC to control the extension of the telescopic member 228 and the actuation of the crust breaker device 250 to dislodge and break the crust to free the spent anode. The PLC controls the rotation of the rotatable platform through approximately 180 degrees. The TOF camera 534 mounted on telescopic member 224 obtains positional data on the position of the first anode gripper apparatus 310a and the spent anode. The processing unit receives real time positional data from the TOF camera 534 to issue signals to the PLC to control the extension of the telescopic member 224 to move the first anode gripper apparatus 310a adjacent to the spent anode. The processing unit receives real time positional data from the TOF camera 534 to issue signals to the PLC to actuate the first anode gripper apparatus 310a to grip the spent anode. Once gripped, the PLC controls the retraction of the telescopic member 224 to lift the spent anode out of the bath. The PLC controls the rotation of the rotatable platform 160 through approximately 180 degrees. The TOF camera 536 mounted on telescopic member 226 obtains positional data on the position of scoop 270 and the electrolytic bath where the anode was removed. The processing unit receives real time positional data from the TOF camera 536 to issue signals to the PLC to control the extension of the telescopic member 226 and to actuate the scoop 270 to remove solid materials from the bath and prevent any obstacles to the positioning of the replacement anode in the bath. The PLC controls the rotation of the rotatable platform 160 approximately 180 degrees. The TOF camera 538 mounted on telescopic member 222 obtains positional data on the position of the second anode gripper apparatus 310b and attached replacement anode. The processing unit receives real time positional data from the TOF camera 538 to issue signals to the PLC to control the extension of the telescopic member 222 and fine adjustment of the second anode gripper apparatus 310b to accurately position the attached replacement anode into the bath.
In the above example the anode replacement system 200 is described as having an attached replace anode. However, it will be appreciated that the system 600 may identify a replacement anode storage area. The system may control the movement of the crane, positioning system, first trolley, second trolley and/or the second anode gripper apparatus 310b to collect the replacement anode from the anode storage area. It will be appreciated that the system may identify a storage area to dispose of the spent anode. The sensor system may control the movement of the crane, positioning system, first trolley, second trolley and/or the first anode gripper apparatus 310a to deposit the spent anode into the spent anode storage area.
The sensor system is configured to generate 3D position information of a potline, pot, one or more pot lids, one or more anode and/or a lid handle, in a potroom. The sensor system is configured to generate 3D position information of the components of the anode replacement system in relation to the pot in the pot room. In this example the sensor system has a camera system that generates position information for the crane, anode replacement system. The sensor system is capable of accurately identify a particular anode assembly in a pot.
In step 412 the sensor system uses data from a camera system to identify the position of the spent anode in the pot and identifies the lids which must be temporarily removed to access the spent anode. Using the sensor data, the processor 612 in stage 414 plans a movement path for the crane and lid handling system in the work environment to grip the lid. The control unit 614 at step 416 implements the movement path controlling the movement of the crane on which the lid handing system 50 is mounted along a horizontally axis to locate the lid handing system roughly adjacent to one or more lids to be removed and to grip the lid. The control unit 614 controls the movement of the positioning apparatus on the crane along a horizontally Y axis to locate the anode replacement system roughly adjacent to the position of the spent anode and the one or more lids to be removed. The lid handing system is mounted to the first trolley of the crane. The control unit controls the movement of the first trolley 116 along a horizontal X axis.
The lid handing system has a lid handling robot with jaw members configured to grip the handle of the lid. One or more sensors in the vision system controls the extension of telescopic members to lower the lid handling robot into a working deployed condition. In this example the sensor is a TOF camera.
The sensor system monitors the movement of the crane, robot assembly and lid handing system to verify in step 418 that lid has been gripped. A feedback signal from the robot assembly, grippers and/or sensor system confirms that the lid is correctly attached to the robot and is ready to be securely lifted. If the plan is not executed correctly then steps 412 to 616 are repeated to locate the lid handing system and grip the lid.
The lid gripper apparatus vibrates the attached lid to remove hazardous dust and assist in dislodging a lid if it stuck before the lid handling robot is actuated to lift the lid from the pot. The TOF camera of the vision system follows the movement path of the robot when lifting the lid, to allow full control of the robot movement to confirm that the lid and lid handle are being lifted. When lid gripping movement path has been correctly executed by the control system and the lid has been gripped the sensor system in step 420 identifies the position of the lid storage area. Using the TOF camera sensor data, the processor in stage 422 plans a movement path for the lid handing system to the lid storage area. In step 424 the control system controls movement of the lid handing system to the lid storage area when the lid is temporally deposited. The steps 412 to 424 are repeated until the required number of lids has been removed to access and replace the spent anode. The sensor system confirms that the required lids have been temporarily removed to access and replace the spent anode.
In step 434, the processor plans a movement path to locate and actuate the crust breaker to break the crust surrounding the anode in the pot. The control system in step 436 executes the planned movement and actuation plan of the crust breaker to break the crust. The accurate positioning of the anode replacement system is crucial to ensure that the crust breaker 250 is positioned and orientated correctly to break and clear crust from an anode to be replaced. The control system controls the extension and movement of telescopic member 228 to accurately position the crust breaker device 250 adjacent to an anode to be replaced. The crust breaker device 250 is actuated to dislodge and break the crust to free the spent anode.
In step 438 the vision system verifies that crust surrounding the anode has been successfully broken. If the crust has not been broken, then steps 434 and 436 are repeated.
When crust has been successfully broken the crust, in step 440, the TOF camera 534 mounted on telescopic member 224 obtains positional data on the position of the first anode gripper apparatus 310a and the spent anode in the pot. In step 442, the processor in plans a movement path to locate the anode gripper apparatus 310a of the anode handling system adjacent to the spent anode. The control system in step 444 executes the planned movement. In this example the control system controls the movement of the second trolley along a horizontal Y axis and controls the rotatable platform to rotate 180 degrees about rotational axis “A” and telescopic member 372 is extended to bring the first anode gripper apparatus 310a adjacent to the spent anode.
The sensor system monitors the movement of the anode gripper apparatus of the anode handling system to verify in step 446 it is in the correct position. If the sensor system detects that the anode gripper apparatus 310a is not in the correct position, then steps 442 to 446 are repeated.
As shown in
The replacement anode may be positioned in the pot with a vertical offset of up to 20 mm above the calculated position. The at least one sensor may be configured to track a marking or position on a spent anode or shaft of a spent anode in relation to a marking or position on a pot structure. The sensor system may reference the distance from a marking or position on the spent anode to the bottom of the anode.
Additionally, or alternatively the at least one sensor may measure a position on the anode shaft such as where the shaft was originally clamped as a first reference point. The at least one sensor may measure the current clamp position on the shaft as a second reference point. The processing system may calculate a distance that the anode shaft has travelled as the anode has been consumed and gradually lowered into the pot. This may allow the height of the remaining anode block to be determined and the distance between the lower surface of the spent anode block and the upper surface of a cathode. The replacement anode may be positioned in the pot at the calculated distance.
The at least one sensor in the vision system may be configured to measure and/or track at least one position data point of the spent anode and/or the replacement anode. The at least one position data point may be a shaft position in the X, Y, and/or Z axes. The at least one position data point may be a position of a surface of the replacement anode with respect to the height of the molten electrolyte. The at least one position data point may be position of the end of the anode shaft of the replacement anode with respect to the height of the molten electrolyte. The at least one sensor may be configured to measure the bath temperature. The at least one sensor may be configured to measure gas emission levels. The at least one sensor may be configured to measure current flow through at least one anode assembly.
In step 482, the processor plans a grip operation to accurately grip the shaft of the anode using the anode gripper apparatus 310a. The control system in step 484 actuates the first anode gripper apparatus 310a such that clamp support arms 330 and 332 engage the clamp 40. The lock members 344, 346 receive the lugs 40a and 40b of the clamp and are moved to a locked position. The jaws members 322, 323 grip the anode shaft 24. The anode gripper apparatus is configured to grip the anode shaft 24 at a position approximately midway along its longitudinal length. However, the anode gripper apparatus may be controlled or set to grip the anode shaft 24 at any position along its longitudinal length. This grip position provides more controlled handling and positioning of the anode. The vision system verifies that the anode shaft has been gripped. If it is not gripped, then steps 482 and 484 are repeated.
In steps 500 and 502 the TOF camera 536 of the vision system mounted on telescopic member 226 obtains positional data on the position of scoop 270 and the exposed section of electrolytic bath where the anode was removed. In step 504, the processor plans a movement path to locate and actuate the scoop to removed solid materials from the crucible. The control system in step 506 executes the planned movement and actuation plan of the scoop. The control system controls the rotation of the rotatable platform through 180 degrees and the telescopic member 226 is extended. The scoop actuated to removed solid materials from the crucible 14 and prevent any obstacles to the positioning of the replacement anode in the crucible 14.
In step 508 the TOF camera 536 verifies that molten bath is free from debris. If the TOF camera 536 detects crust fragments or debris in the molten bath, then steps 504 and 506 are repeated. In step 510 the TOF camera 538 mounted on telescopic member 222 obtains positional data on the position of the second anode gripper apparatus 310b, attached replacement anode and the exposed section of the molten bath. In step 512, the processor plans a movement path to locate the second anode gripper apparatus 310b and attached replacement anode adjacent to the molten bath. The control system in step 514 executes the planned movement.
In this example the control system controls the movement of the rotatable platform to rotate through approximately 180 degrees about rotational axis “A” and telescopic member 222 is extended to locate the replacement anode adjacent to the molten bath. The TOF camera 538 of the vision system in step 516 monitors the movement of the anode gripper apparatus and replacement anode to verify it is in the correct position. If the vision system detects that the anode gripper apparatus and replacement anode is not in the correct position, then steps 512 to 514 are repeated. When anode gripper apparatus 310b is in the correct position the processor in step 518 determines the correct orientation of the replacement anode, specifically the anode block in the molten bath. The processor uses the sensor data collected in step 480 of
The accurate positioning of the replacement anode is crucial to maintain the efficiency of the electrolytic process. The anodes in the pot are replaced at different times and therefore are in operation for different durations resulting in a different degree of consumption for each spent anode. The height at which the replacement anode should be suspended is different for each anode and for each replacement operation. The upper surface of the molten bath is not level and the surface of the surrounding crust is not level. The crust height is typical higher at the centre of the pot. Anode assemblies are consumed to form a concave shape. Therefore, the position of each anode in the anode array in the pot is different. The position of the replacement anode and degree of immersion in the electrolytic bath must be adjusted every time taking into account parameters such as the level of consumption of the spent anode and the curvature of the crust. The height of the lower surface of the replacement carbon anode from the cathode must be the same as the height of the lower surface of the expired carbon anode from the cathode to ensure efficient electrolysis. In this example the vision system has at least one optical sensor which measures and/or tracks at least one position data point of the replacement anode before it is secured to the electrolytic cell. The processor may use at least one data point to determine the optimal orientation, position and/or height of the anode assembly in the bath.
The control system in step 520 controls the tilt and height adjustment mechanism of the anode gripper apparatus to locate the replacement anode in the correct orientation in the crucible. The lower surface of the replacement carbon anode should preferably be parallel with the cathode to ensure efficient electrolytic reaction. The anode gripper apparatus has fine tuning adjustment for accurate placement of the anode. The height of the anode assembly may be adjusted +/−100 mm. The tilt and/or height adjustment of the replacement anode may result in the anode clamp rubbing against the clamp hooks dislodging any debris or dust and forming a good electrical connection.
Once in the correct anode orientation the second anode gripper apparatus 310b is actuated such that the lock members 344, 346 are moved to an unlocked position to release the lugs 40a and 40b and clamp 40 which are received by clamp hooks 28 mounted on the pot structure, best shown in
In step 520 using feedback from the sensor position the system accurately secures the lower surface of replacement anode at a same level in the molten bath as the previous spent anode within a threshold of +/−1 mm. Telescopic member 222 is retracted to lift the second anode gripper apparatus 310b away from the secured replacement anode. The sensor system in step 522 monitors the position of the replacement anode to verify it is in the correct position. If the sensor system detects that the replacement anode is not in the correct position, then steps 518 to 522 are repeated. After an anode replacement operation has been completed the sensor system identifies the position of the lids and the lid handles in the storage unit and the lid handling robot is operated to return the lids to the pot support structure. The sensor system controls the movement of the replacement anode system to deposit the spent anode into a spent anode storage area.
The sensor system may use at least one sensor such as an optical camera or infra-red camera to confirm that the lids have be successfully returned to the pot and are in the correct position. The infra-red camera may be capable of detecting heat loss through gaps from a misaligned lid. The placed lid is retuned within a 10 mm tolerance of the correct position. The camera system may be used to confirm that the lid and lid handle has been released from the robot.
The anode replacement system is either repositioned to perform another pot maintenance operation or is moved to a stowed condition guided by the sensor system data, processor, and control system.
It will be appreciated that the operational steps described above in relation to
Anode replacement system 700 has a positioning system 710. Positioning system 710 has a frame support 712 comprising two support beams 714a, 714b which are substantially parallel to each other on which a trolley 750 is movably mounted relative to the support beams 714a, 714b.
The positioning system 710 is movably mounted on two substantially parallel runway beams 722a and 722b on which rails 719 are mounted. The runway beams 722a and 722b support the positioning system 710 to which a piece of equipment or load is attached. In this example an anode handling system 800 is attached. The two support beams 714a, 714b act as crane bridge girders and form a crane bridge 704 which is movably mounted on support rails 719 forming an overhead crane 702.
In this example the runway beams form part of the building structure. However, alternatively the runway beams 722a and 722b may be mounted on supports such as column supports movable in three axes or stationary column supports. The positioning apparatus 710 has cross beams 718a, 718b at each end of the support beams 714a, 714b. As best shown in
The positioning apparatus has a trolley 750 movably mounted relative to the support beams 714a, 714b. The support beams 714a, 714b have a longitudinal guide 720 located on an upper surface 715 of the support beams 714a, 714b. The longitudinal guide 720 spans the longitudinal length of the support beams 714a, 714b. In this example the longitudinal guide 720 is a toothed rack 731. A plurality of QR codes 713a are arranged at known positions along the longitudinal length of the support beams 714a. The camera system 711 captures image data of the QR codes 713a to accurately locate the position of the trolley 750 along the longitudinal length of the support beam 714a.
The trolley 750 has a trolley frame 724 comprising two girder supports 742a, 742b and two drive supports 744a, 744b. The two drive supports 744a, 744b are connected to the supports 742a, 742b as end supports with the drive supports 744a, 744b arranged substantially parallel with the frame support beams 714a, 714b. The two supports 626a, 626b span the distance between the substantially parallel support beams 714a, 714b. The drive supports 744a, 744b have pinion gears 748 at each end.
The pinion gears 748 are rotatably mounted on the drive supports 744a, 744b. The trolley frame 724 supports reversible servomotors 743 connected to pinion gears 748. Each pinion gear 748 has teeth 749 which cooperate with teeth 722b on the rack 731 such that when the servomotors 743 rotates the pinion gear 748 the pinions 748 travel along the rack 731 which moves the trolley 750 along the support beams 714a, 714b shown as arrow “F” in
The servomotors 743 are connected to a control unit 814 to allow the accurate movement of the trolley 640 along the support beams 714a, 714b. The control unit is configured to allow remote and/or automated movement and positioning of the trolley up to +/−0.5 mm accuracy.
A rotatable platform 760 is rotatably mounted on base 752 of the trolley 750. The rotatable platform 760 is supported by gearing assembly. A drive assembly (not shown) is configured to rotate the platform. The drive assembly is connected to the control unit 814 to provide controlled rotational movement of the rotatable platform 760. In this example an anode handling system 800 is attached to the rotatable platform 760. The control unit controls the rotation of the rotatable platform 760 and the anode replacement system 800 in a clockwise or anticlockwise direction relative to the positioning system about rotational axis shown as “A” in
The positioning system allows the controlled movement and positioning of the anode handling system 800 by actuating the servomotors 717a, 743 to move the crane bridge 704 and/or trolley 750 to a desired position with millimeter precision.
The frame 810 houses and supports four telescopic members 820 shown to be in a fully retracted position. Each of the telescopic members 820 supports at least one pot maintenance functional module. In this example two anode handling two anode handling systems 900, crust breaker device 950 and scoop 970 are each supported on a separate telescopic member 820. Each of the telescopic members 820 is connected to an actuator 915. In this example servomotors 915a, 915b, 915c, 915d are used. Actuation of each servomotor move the respective telescopic members 820 between extended and/or retracted positions. The servomotors allows movement to up to telescopic members to locate the at least one pot maintenance functional module with up to +/−0.5 mm accuracy.
The operation of use of each of pot maintenance functional modules of the anode handling system will be understood from the description of
It will be appreciated the anode replacement systems described above may use electric actuators such as servomotors to accurately control the position and/or movement of the support, first trolley, second trolley and/or telescopic members to within a range of 0.5 mm to 10 mm.
It will be appreciated that positional markers may be located on multiple support beams or on multiple surfaces of support beams to provide redundancy in the event that one or more positional markers a support beam surface become obscured with dirt or damaged. It will be appreciated that positional markers may be located on components on the anode replacement system such as the telescopic members. This may allow accurate positional control over the extension/retraction of the telescopic members. In the above examples the camera system for detecting the positional markers is described as being above the crane. It will be appreciated that different sensor types may be used capable of detecting the positional markers. It will be appreciated that the at least one sensor may be mounted or positioned on components of the positioning system such as the support, first trolley or second trolley. The at least one sensor may be located or mounted on a component of the crane or vehicle supporting the positioning system. The at least one sensor may be located or mounted on a component of a surrounding structure such as a floor, walls and/or roof.
It will be appreciated that the anode replacement system can adopt different configurations depending on the structure or crane is installed or supported. The system may allow crane movement, anode alignment, gripping, lifting and replacement of anodes autonomously. It does not require personnel in the vicinity of the pots during hazardous pot maintenance operations. It will be appreciated that the anode replacement system can support different modular functional devices in different configurations depending on the application. Different modular devices may be attached to the movable members in the anode replacement system.
The anode replacement system or components of the anode replacement system may be retrofitted to an existing aluminium production plant to make the plant fully or partially autonomous. The anode replacement system, positioning system or components of the anode replacement system or positioning system may be retrofitted to a crane system.
The invention provides a system for the replacement of anodes in pots of an aluminium production plant. The system comprises a support frame and at least one movable member mounted on the support frame wherein the at least one movable member comprises at least one anode gripping apparatus. Each of the at least one anode gripping apparatus configured to grip a shaft of at least one anode assembly. The system comprise a sensor system configured to generate or collect position information to control the position of the at least one movable member and/or the at least one anode gripper apparatus.
The system may be capable of gripping the anode by the anode shaft which allows the anode to be held securely and stable. This may allow the anode to be gripped at a position close to the anode block and assist in the precise movement and accurate positioning of the anode in the molten bath. The system may be capable of gripping the anode by the anode shaft at a position close to the anode clamp position which allows the anode to held securely and positioned accurately until it is clamped into place.
The system may be capable of determining a precise orientation of a spent anode is before it is removed from the pot, and a replacement anode arranged and installed in precisely the same orientation. The precision placement of the replacement anode at the correct height and position in the electrolytic bath allows a highly efficiency electrolytic process to be maintained. Optionally the replacement anode assembly may be located in the pot at precise vertical offset.
The system may be capable of accurately determining an optimal position of each anode in the anode array which is bespoke for each pot. The systems and method of aspects of the invention may be capable of adjusting the degree of immersion of a replacement anode in the electrolytic bath and may take into account the curvature and height of the crust to allow an efficient electrolysis process.
The ability to accurately control the orientation, positioning and movement of anode assemblies mitigates the risks to personnel and infrastructure and reduces the risk of human error in a dangerous environment.
By providing a system capable of controlled movement of an anode replacement system with a high degree of accuracy may increase the efficiency of an industrial plant. The anodes may be replaced using the present invention quickly with a higher degree of precision. This may reduce the emissions of toxic gases released during the anode replace operation. The system may provide controlled movement of an anode replacement system with high or fine resolution and excellent repeatability. This may overcome issues of anode replacement process prone to variation by manual operators and misalignment of anodes due to human error.
The present invention in its various aspects may provide an improved system and method for quickly and accurately replacing anodes in an electrolytic pot. The system may use sensor system data to precisely control movement of the pot maintenance system for anode replacement, components of which are mounted on the crane, positioning system, first trolley and/or second trolley. The sensor system may precisely control the movement of the anode replacement system along the crane to perform one or more tasks at first pot location before the anode replacement system is moved to perform one or more tasks at first pot location. This mitigates the requirement to reposition the crane thereby mitigating exposure of the pot room to toxic emission and providing a more efficiency method saving time and costs.
Throughout the specification, unless the context demands otherwise, the terms ‘comprise’ or ‘include’, or variations such as ‘comprises’ or ‘comprising’, ‘includes’ or ‘including’ will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.
The foregoing description of the invention has been presented for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The described embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilise the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore, further modifications or improvements may be incorporated without departing from the scope of the invention herein intended.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2104621.4 | Mar 2021 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/058735 | 3/31/2022 | WO |
