Temperature tracking of a current collector used on a roller for an electrolytic line

Abstract

A method for monitoring the temperature of an electrical collector (200) for a rotating current-conducting roller (100) in a continuous electrolysis line. The method includes measuring the collector's temperature by a sensor (450) attached to the collector and transmitting the successively measured values ​​wirelessly to a monitoring computer station (900).

Description

[0001] The invention falls within the field of current-conducting rollers for electrolysis lines in the steel industry, for the treatment and surface coating of steel, in particular.

[0002] The rollers in question are current-conducting rollers used in tin (tinning), chrome (chrome plating), or nickel deposition lines. Typically, the deposition is carried out on steels or other alloys.

[0003] The deposition is done by electrolysis on typically metal sheets such as steel sheets, with continuous operation, with a steel strip (or other alloy) being driven through a succession of treatment cells with electrolyte baths using soluble anodes which allow the deposition of the metals concerned on the surface of the steel strips or other alloys which, by application of a potential difference, act as moving cathodes.

[0004] Each cell consists of a bath in which the steel strip is immersed and advances before emerging. The strip's progression is achieved using rotating rollers, one of which is a conductive roller that acts as a cathode to polarize the strip's metal, causing the deposition of metal ions on its surface. These metal ions originate from the soluble anode. Insoluble anodes can also be used, in which case the metal ions come from the electrolytic solution employed.

[0005] Electrolytic cells are therefore composed of a tank containing the electrolyte, anodes, a bottom roller and a conductive roller which acts as the cathode.

[0006] Current flows from the anode to the cathode, and copper commutators, copper being an excellent conductor, are mounted for this purpose at the ends of the conductive roller that forms the cathode. Alternatively, another electrically conductive material could be used. Because the rollers rotate and the commutators are fixed (press-mounted and / or secured with a nut) at both ends, the commutators rotate at the same speed. The roller and commutator together constitute a rotating, current-conducting system.

[0007] Fixed electric brushes, powered by the industrial building's electrical supply, are in contact with the outer, circular perimeter of the commutators to ensure current flow. Contact between the fixed brush and the rotating commutator must be maintained continuously despite the rotation of the rotating system and therefore the commutator. Overheating of the electric commutators can lead to malfunctions in the processing lines.

[0008] Indeed, the distribution of electrical power is very sensitive to the quality of the contacts of the different elements constituting the rotating current-conducting system.

[0009] Poor contact between the sheet metal being treated and the surface of the drive roller, or incorrect positioning or improper tightening of the commutators at the end of the drive roller, can lead to overheating of the electrical commutators. This is also the case if there is significant wear on the commutator brushes.

[0010] The commutators are rotating cylindrical copper components, and copper, which has a high electrical conductivity, is also prone to expansion when the temperature increases. Therefore, if the commutators heat up, they lose, or risk losing, contact with the ends of the conductive roller on whose trunnions they are mounted, and in any case, they lose their ability to transmit current correctly. Document CN216427457U discloses a rotating current-conducting system for a continuous electrolysis line, comprising a central roller and two trunnions fixed to the respective ends of the roller apron, and a current collector mounted on one of the trunnions, which trunnion is configured to conduct current from the collector to the apron. A temperature sensor integrated into the rotating system measures the temperature of the central roller.A wireless communication device transmits the measured temperature value to a monitoring computer station.

[0011] The present invention proposes continuous temperature control of rotating electrical collectors, so as to be able to detect as early as possible and in real time, temperature deviations from a reference value, which may be a warning sign of a loss of electrical contact, with a consequence a deterioration of the electrolytic deposit on the strip of metal or metal alloy being treated.

[0012] To solve this problem, until now the only option was to use a thermal camera pointed at each collector from time to time to check its temperature, an extremely laborious solution that would considerably delay the detection of emerging difficulties.

[0013] To solve this problem, a current-conducting rotating system for a continuous electrolysis line is proposed here. It comprises a roller for driving the metal strips and a collector for contacting the brushes. The rotating system includes a temperature sensor integrated within it, designed to measure the temperature of the collector, and a wireless communication device transmitting the measured temperature. The design is based on the most direct contact possible, via an adapter made of copper, brass, or aluminum, all excellent heat conductors.

[0014] This temperature information, obtained remotely on a continuous or near-continuous basis, will allow for the continuous monitoring of unexpected temperature increases in the electrical collectors, triggering an alarm temperature. The production line operator will be alerted to any imbalance in electrical conductivity and can prevent potential loss of quality in the sheet metal processing.

[0015] The rotating system may include a sensor support made of brass, copper, or aluminum, attached to the manifold, in a cavity of which the temperature sensor is placed. This is the adapter piece mentioned above, which houses the sensor in a dedicated and secure compartment and transmits heat to it in the most direct way possible.

[0016] The temperature sensor can be held against the collector by a nut mounted on a roller trunnion.

[0017] Each end of the rotating roller carries a collector of electricity that interacts with respective fixed brushes. The roller includes a temperature sensor for each collector—thus two temperature sensors—and at least one wireless communication means that transmits the temperature value measured by each sensor. The wireless communication means may be shared between the two sensors or be specific to each sensor. In other words, the system according to the invention may include two wireless communication means, one for each temperature sensor.

[0018] A monitoring system is also proposed, comprising at least one rotating system as described above, and control means—typically a computer-based monitoring station—connected to the communication means of each rotating system. This monitoring station is capable of generating alarms when the temperature of at least one manifold of one of the rotating systems in the monitoring system reaches or exceeds a predetermined alarm threshold.

[0019] A monitoring method is also proposed, implemented by the monitoring system as described above. This method ensures the monitoring of the temperature of at least one electrical collector carried by a rotating current-conducting roller for a continuous electrolysis line. The collector and roller form a rotating system in which a temperature sensor is integrated. The method includes the continuous measurement of the temperature of the roller collector(s) of each rotating system and the simultaneous transmission of the successively measured values ​​to the monitoring computer station.

[0020] The computer monitoring station can monitor the exceeding of an alarm threshold, which threshold is between 80 and 110 °C, preferably between 80 and 100 °C, and generate an alarm if this alarm threshold is exceeded.

[0021] The computer monitoring station can notify an operator in case of an overrun.

[0022] When the monitoring system includes at least two rotating systems, and the collector temperatures of at least two rollers are monitored, the monitoring station includes a step to identify the roller whose collector(s) have a measured temperature greater than or equal to the determined alarm threshold.

[0023] The computer monitoring station can control the shutdown of the power supply to the roller whose collector(s) have a measured temperature greater than or equal to the determined alarm threshold.

[0024] The computer monitoring station can order the resumption of the power supply to the collector(s) of the roller in question when the temperature of said collector(s) is below a second determined threshold, which second threshold is below the alarm threshold. The description will be continued in relation to the figures which are as follows.

[0025] Therefigure 1 is a side view of a current-conducting roller, without its commutators.

[0026] There figure 2 is a view of one end of a current-conducting roller, equipped with a collector, and forming a rotating current-conducting system.

[0027] There figure 3 is a front view of a sensor support according to the invention and

[0028] there figure 4 is a cross-sectional view of the sensor support according to the invention, the sensor being visible in both figures.

[0029] There figure 5 is a cross-sectional view of the collector mounted on a current-conducting roller, forming a rotating current-conducting system.

[0030] There figure 6 is a side view of the roller equipped according to the invention.

[0031] There figure 7 is a three-quarter view, from the same angle as the figure 2 from the end of a current-conducting roller equipped with a collector, and a sensor according to the invention, the assembly forming a rotating current collector system.

[0032] There figure 8 is a view in situ, in an industrial installation of rollers implementing the invention.

[0033] [ Figure 1 In figure 1 A current-conducting roller 100, as known in the prior art, is shown. Such a current-conducting roller 100 comprises a central apron 110 between two trunnions 120 on its two sides. The apron 110 is a wide cylinder with a straight, circular cross-section, and the trunnions 120 are coaxial with the apron 110 and attached to its two opposite sections.

[0034] The trunnions originate on the lateral faces of the deck 110. They narrow as they move away from the deck 110 and include several successive offsets defining different sections, one of which constitutes a span for a collector 130.

[0035] The bearing surface for collector 130 is a section along the longitudinal axis of the trunnion 120 which is slightly tapered and narrows as it moves away from the apron 110. Such bearing surfaces for collector 130 are present at both ends of the current-conducting roller 100, even if the two trunnions are not necessarily strictly symmetrical to each other.

[0036] [ Figure 2 ] There figure 2 is a three-quarter view of one of the faces of the deck 110, of the current-conducting roller 100.

[0037] One of the trunnions 120 is visible, the other being hidden due to the view, and this time a collector 200 is visible in the figure, which is a large cylindrical piece with a straight and circular cross-section fitted onto the collector seat which was referenced 130 in figure 1 and which is not visible in figure 2 One end of the journal 121 protrudes from the commutator 200. A nut 300 is fixed around the end of the journal 121, securing the commutator 200 to the journal 120. The roller 100, the commutator 200, and the nut 300 form a rotating, current-conducting system. The electrical contactors bear against the cylindrical surface of the commutator during the rotation of the rotating system. The commutator has a significant radial thickness (approximately 50% of its total diameter), defining a gap between the surface of the commutator bearing surface 130, to which the commutator 200 is fixed, and the outer surface of the commutator 200, against which the electrical contactors will bear and rub.

[0038] [ Figure 3 In figure 3 A sensor support 400 according to the invention, made of brass, copper, or aluminum, is shown. It is used between the nut 300 and the collector 200 and is shown here from the front, with its front face 402 visible. It is a disc-shaped part, defined by a flat front face and a flat rear face, the front of which is defined by a circular perimeter and having at its center a circular central hole 408, or bore, passing completely through the part and thus forming an opening. Furthermore, around this central hole 408 is a circular annular flat 410 whose external diameter is slightly greater than half the external diameter of the sensor support 400. The diameter of the central hole 408 is approximately half the diameter of the annular flat 410.

[0039] The annular flat 410 is surrounded by a peripheral ring whose thickness is the maximum thickness of the sensor support 400. On this ring, within an angular sector, is formed a generally rectangular recess 430, creating a cavity that opens onto the front face 402. The four corners of the rectangle are slightly rounded. The bottom of the recess is flat. The recess 430 houses a temperature sensor 450, which is covered by a cover 420 secured at both ends by screws 421.

[0040] [ Figure 4 ] There figure 4 The diagram shows the sensor support 400 in cross-section. It can be seen that the annular flat 410 has a depth of approximately two-thirds the thickness of the sensor support 400, which is flat on both sides, the rear face 401 being pierced only by the central hole 408. The recess 430 has a depth roughly similar to that of the annular flat 410.

[0041] [ Figure 5 ] The figure 5 This represents the system mounted on the current-conducting roller 100, where the collector 200 is positioned on the bearing surface for the collector 130. The sensor support 400 is placed against the outer side of the collector 200, creating direct contact between the rear face of the sensor support 401 and the side of the collector 200. The rear face 401 of the sensor support 400 is thus pressed against the left side of the collector 200. A nut 300 is placed in the flat 410 on the front face 402 of the sensor support 400. The end of the trunnion 121 protrudes from the central hole 408 and from the central thread of the nut 300. Thus, by using the nut 300, the sensor support 400 is screwed against the collector 200, by the rear face 401 of the sensor support. 400 on the external face of the collector 200, according to an annular support of revolution symmetry around the longitudinal axis of the current-conducting roller 100.

[0042] The contact is notably present on a continuous peripheral annular surface around the entire 360° of the assembly. Indeed, since the outer face of the manifold 200 has an annular flat around its central bore for half the distance between the opening of the threaded hole and the outer circumference, the contact between the sensor support 400 and the manifold 200 occurs on a peripheral annular surface on the lateral face of the manifold 200. It is directly above this peripheral annular surface that the temperature sensor 450 is positioned. It is thus directly exposed, through the contact between the material of the sensor support 400 and the manifold 200, to temperature variations in the outermost layers of the manifold 200.

[0043] Furthermore, the figure shows a spring washer 460 between the nut 300 and the bottom of the flat 410 of the sensor support 400, designed to ensure the correct positioning of the nut 300 on the thread of the end of the trunnion 121. More precisely, the spring washer 460 is placed around the end of the trunnion 121 against the bottom of the annular flat 210, and after this spring washer 460, the nut 300 is placed and screwed onto a corresponding thread of the end of the trunnion 121.

[0044] A computer 900 is shown, and each temperature sensor 450 communicates with this computer 900 via wireless communication methods such as Wi-Fi, ZigBee, Bluetooth, or others. The wireless nature of the communication is useful for maintaining connectivity despite the continuous rotation of the current-conducting roller 100. Information is transmitted in real time to continuously monitor the temperature at the interface between the rear face of the sensor holder 401 and the outer side of the collector 200.

[0045] Computer 900 is informed in real time of the evolution of the temperature recorded by the temperature sensor 450. The assembly formed by at least one rotating system of the invention and the computer monitoring station 900 is a monitoring system.

[0046] [ Figure 6 ] There figure 6 shows that similar means are put in place at the other end of the current-conducting roller 100, such that there is on each of the two collectors 200 present at the two ends of the two trunnions 120, a sensor 450 communicating wirelessly with the computer 900 which is therefore able to visualize and follow in real time the temperatures at the level of the collectors 200.

[0047] [ Figure 7 In figure 6 we have represented the system of the figure 5 viewed from a three-quarter angle, the temperature sensor 450 is protected by a cover 420.

[0048] Current flows from the roller surface to the ends where the electrical collectors are attached. These electrical collectors are made of copper, and only one of the two collectors, referenced as 200, is visible in the figure. When the collectors do not make good contact with the roller journal, or when too much electricity flows through them, the collector heats up, expands, and loses even more contact with the journal. This results in further overheating. This phenomenon creates electrical arcs, leading to a decrease in the plant's productivity and progressively irreversible damage to the equipment. Thanks to the invention, this problem is solved by using a temperature sensor that communicates wirelessly via radio waves.

[0049] The 900 computer integrates high and low temperature points into a computer program, and triggers an audible or visual alarm for the industrial site's operations team if the temperature limits are exceeded upwards or downwards.

[0050] [ Figure 8 Finally the figure 8This allows visualization of the operation in a factory where numerous current-conducting rollers 100 are present and rotate independently of each other. Therefore, numerous sensors 450 have been installed at each end of the current-conducting rollers 100. Wireless communication and a computer 900 enable monitoring of the temperatures measured by each sensor, despite the rotation of the rollers and thus the collectors and sensors. This allows an operator to independently observe an abnormal temperature increase or to trigger audible or visual alarms as soon as a temperature threshold is exceeded by any of the sensors. The figure shows one sensor and one curve per roller, but as a general rule, two sensors and two curves should be monitored per roller.

[0051] The monitoring station 900 identifies the roller 100 whose collector(s) 200 have a temperature equal to or greater than the alarm threshold. Thus, in addition to generating an alarm, the monitoring station can generate information identifying the roller whose collector(s) are overheating. Furthermore, the workstation 900 can control the shutdown of the power supply to the collector(s) 200 whose temperature is equal to or greater than the alarm threshold, for example, by preventing contact between the collector(s) 200 and the electric brushes.

[0052] Finally, if the temperature of the collector(s) in question 200 falls below a second temperature threshold lower than the alarm threshold - for example between 70 and 80 °C - then the monitoring station commands the resumption of the power supply to the collector(s) in question, by putting the electric brushes back into contact with said collector(s) 200. On the other hand, if the temperature of the collector(s) increases a second time above the alarm threshold, the workstation will indicate to the operator that maintenance intervention on the roller(s) 100 is necessary.

[0053] The invention is not limited to the embodiment shown but extends to all variants within the scope of the claims.

Claims

1. A current-conducting rotating system for a continuous electrolysis line, comprising a conductive roller (100) comprising a central apron (110) and two trunnions (120) secured to the respective ends of said apron (110), and at least one electricity collector (200) mounted on one of the trunnions (120), which trunnion (120) is configured to conduct the current from the collector (200) to the apron (110), characterized in that the system comprises at least one temperature sensor (450) secured to the collector (200) and arranged to measure a temperature of said collector (200), and wireless communication means connected to the temperature sensor (450) and configured to emit the measured temperature value.

2. The current-conducting rotating system according to claim 1, characterized in that it comprises two collectors (200) respectively mounted on the trunnions (120), in that it comprises two temperature sensors (450) respectively secured to the collectors (200) and in that it comprises two wireless communication means respectively connected to the temperature sensors (450).

3. The current-conducting rotating system according to claim 1 or 2, characterized in that it comprises, for each temperature sensor (450), a sensor support (400) made of brass, copper or aluminum, attached to the collector in question (200), and in a cavity (430) of which the temperature sensor (450) in question is placed.

4. The current-conducting rotating system according to any one of claims 1 to 3, characterized in that each temperature sensor is held against the collector in question (200) by a nut (300) mounted on the trunnion in question (120) of the roller (100).

5. A monitoring system comprising at least one current-conducting rotating system according to any one of the preceding claims, and a monitoring computer station (900) connected to the wireless communication means of said rotating system.

6. A monitoring method implemented by a monitoring system according to claim 5, which method comprises the successive steps of: • Continuously measuring the temperature of the collector(s) (200) of the roller (100) of each rotating system and concomitantly transmitting the successively measured values to the monitoring computer station (900); • If the measured temperature reaches a determined alarm threshold, generating an alarm by the monitoring computer station (900).

7. The method according to the preceding claim, characterized in that the alarm threshold is reached when the temperature of the collector (200) measured by the sensor (450) is between 80 and 110 degrees Celsius.

8. The method according to claim 6 or 7, wherein at least two conductive rollers (100) are monitored, characterized in that it comprises a step of identifying the roller (100) whose collector(s) (200) exhibit a measured temperature greater than or equal to the determined alarm threshold.

9. The method according to any one of claims 6 to 8, characterized in that the monitoring computer station (900) controls the stopping of the electricity supply to the roller (100) whose collector(s) (200) exhibit a measured temperature greater than or equal to the determined alarm threshold.

10. The method according to the preceding claim, characterized in that the monitoring computer station (900) controls the resumption of the electricity supply to the collector(s) (200) of the considered roller (100) when the temperature of said collector(s) (200) is lower than a second determined threshold, which second threshold is lower than the alarm threshold.

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