MXPA06006992A - Roller cleaning system - Google Patents

Abstract

A roller cleaning system (10) for an oven (20) equipped with a series of motorized rollers (21) each of which is in turn connected to a relative motor-reducer (24) for rotation activation, in turn connected to a relative frequency converter (25) driven by a respective control and activation device (26), said roller cleaning system (10) comprising a control and regulation unit (14) to independently control the rotation rate and direction of each roller of the series of motorized rollers(21) for the advancing of one or more flat blooms (40) and for cleaning at least one roller (34) causing the detachment of the flakes of oxide therefrom by scraping it against a flat bloom (40) with a variation in the rotation rate and/or direction of the same.

Description

CYLINDER CLEANING SYSTEM LAMINATOR DESCRIPTION OF THE INVENTION The present invention relates to a laminating cylinder cleaning system, which can be used in particular to remove oxide flakes from the conveyors of the rolling cylinders of a heating furnace for roughing. for sheet metal or similar products that are going to be laminated. In the steel industry, in the rolling of flat products, the use of fine smelting plants with the use of rolling mill furnaces for direct rolling, is becoming more and more widely disseminated. These plants include a heating furnace for slabs for sheet metal or similar products to be laminated, placed immediately after continuous casting to transfer slabs for sheet metal or similar products to a laminator, designed to optimize the heating temperature of the slabs for sheet metal themselves. The laminator is also found after the oven. The physical transfer of sheet metal slabs into the heating furnaces is carried out by means of a series of motorized rolling mills, from which the term "rolling mill furnace" is derived. Furnaces of rolling mills also allow the movement and temporary residence of sheet metal slabs within said furnaces in the event of unexpected stops of the mill, without having to interrupt the subsequent continuous casting. A typical rolling mill furnace has a series of motorized rolling mills, for example a rolling mill furnace of approximately two hundred motorized rolling mills extends in approximately 250 linear meters. The movement of the sheet metal slabs within the rolling mill furnace is specifically carried out by means of the series of motorized rolling mills. They are designed to optimize the heating of the slabs for sheet metal, and at the same time minimize the thermal exchange between the series of rolling mills and the slabs for sheet metal, during their stay inside the furnace. For this purpose, each roll mill is equipped with one. series of metal conveyors, located on the outer surface and suitable for supporting the slabs for sheet metal and confer them advance movement.

In addition, each rolling mill is equipped with a motor reducer capable of activating its rotation at any pre-set speed by means of a control and a regulating device and a frequency converter, both connected to the motor reducer itself. During its stay in the heating cylinder rolling mill, the slabs for sheet metal undergo oxidation at qalor which causes the formation of a layer on the oxide surface, which grows with time, for the period in which the roughing for sheet metal it remains in the oven. One of the drawbacks that can occur in laminating cylinder furnaces is that the oxide layer can break, which generates flakes which subsequently adhere to the series of conveyors of each motorized conveyor cylinder. Another disadvantage is that a continuation of this process leads to the formation of an additional layer on the surface of the series of conveyors which damages the slabs for sheet and its subsequent lamination. In order to limit these problems, it is possible to minimize flaking by optimizing the heating temperatures of the sheet slabs within the various sections of a roll mill furnace.

Another method is to reduce the dwell time and temperature of the sheet metal slabs within the rolling mill furnaces, and at the same time minimize air infiltration into the furnace itself. One solution to the problem of oxide scale is to clean the series of conveyors of each motorized rolling mill by means of manual plant maintenance operations. One of the drawbacks of this solution is that it requires a large amount of time and there is also no guarantee that the restoration of the motorized rolling mills provides good quality slabs for laminated sheet metal, since this type of operation is very complex and complicated and requires an extremely long period of time to obtain the best results. Another solution considers the replacement of motorized rolling mills. One of the disadvantages of this solution is that it is extremely expensive in economic terms. Another drawback is that it is extremely burdensome in terms of the time needed to replace the rolling mills themselves. It is an object of the present invention to provide a rolling mill cleaning system for a roll mill furnace capable of operating during the operation of the rolling mill furnace itself. A further object of the present invention is to provide a rolling mill cleaning system for a rolling mill furnace which is efficient and which allows the rolling mill furnace to be used without interruption, obtaining slabs of good quality sheet metal or other similar structural sections. A further objective is to provide a system and method for cleaning the rolling mills of a rolling mill furnace which is simple and economical. The general objective of the present invention is to solve the above drawbacks of the known art, in a simple, economical and particularly functional way. A further object is to provide a laminating cylinder cleaning system capable of removing the oxide flakes from the rolling mills of a rolling mill furnace. Another additional objective is to indicate a method for cleaning the rolling mills of a rolling mill furnace which is effective and practical. In view of the above objects, in accordance with the present invention, a laminar roller cleaning system is conceived, having the specific characteristics in the appended claims. The structural and functional characteristics of the present invention, as well as its advantages with respect to the known technique, will appear more clearly from the examination of the following description, with reference to the attached drawings, which illustrate a system for cleaning rolling mill rolls. in accordance with the innovative principles of the invention itself.

IN THE DRAWINGS Figure 1 shows an enlarged side view of a rolling mill of a rolling mill furnace; Figures 2a, 2b and 2c are side elevational views of the rolling cylinder of Figure 1 at successive residence times in a cylinder furnace; Figures 3a and 3b are side elevational views of a rolling cylinder of a first preferred embodiment of a laundering roller cleaning process, according to the present invention, in successive times periods; Figure 4 is an enlarged side view of a second preferred embodiment of a rolling roll cleaning process, according to the present invention; Figure 5 is an enlarged side view of a third preferred embodiment of a roll cleaning process according to the present invention; Figure 6 is an enlarged schematic side view of a rolling mill furnace equipped with a system according to the present invention and connected to a continuous casting plant and a rolling mill; Figure 7 is an enlarged side view of a preferred embodiment of a cleaning system according to the present invention. With reference to the drawings, the roller cleaning system is indicated in its entirety with the number 10 and in the illustrated example, according to the present invention it comprises a control and regulation unit 14 which is preferably connected by means from a common field link 12 to relative control and activation devices 26 in a PLC, each of which in turn is connected to a motor 24 of a respective rolling mill 21 by means of a frequency converter 25 (inverter) which controls the rotation speed of the motor 24 itself. Said cleaning system 10 is applied to a laminating cylinder furnace 20 equipped with a series of laminating cylinders 21 activated in rotation by the respective motors 24. According to a preferred embodiment of the present invention, by means of the control and regulation unit 14, the rolling cylinder cleaning system 10 is capable of independently activating each motorized rolling cylinder of the series of rolling mills 21, modifying, with the time, its rotation speed or direction of rotation without considering the motorized rolling mill rolls remaining from the series of motorized rolling mills 21. According to another aspect of the present invention, there is provided a process for cleaning the rolling mill rolls of a roll mill furnace, to remove the oxide flakes which are deposited on a series of conveyors of at least one roll mill. 34 of a laminating cylinder furnace comprising a series of laminating cylinders 21 of which a group of laminating cylinders 22 is dedicated to a blank for plate 40 or with a similar steel structure. The rotation of each rolling cylinder 21 can be activated independently of the remaining rolling rolls of the series of rolling rolls 21 by means of activation devices. The cleaning process of the rolling mills comprises the following phase: a) activating the rotation of at least one rolling cylinder 34 of at least one group of rolling cylinders 22 with a module speed or direction sufficient to cause at least one of the laminating cylinders 34 scrapes against the blank 40 so as to remove the oxide flakes from at least one rolling cylinder 34. This is carried out by the mechanical action of the blank 40 for at least a rolling mill 34 generated by the difference in speed between the speed of at least one rolling cylinder 34 of the group of rolling mills 22 themselves, and the speed of the cutting for sheet 40 itself which advances with the peripheral speed of the cylinders mills remaining from the group of rolling mills 22. In particular, the chip for sheet 40 is used to remove the oxide flakes from a series of conveyors placed on at least one roll mill, as if it were a tool. From . In accordance with the method of the present invention, it is possible to activate one or more rolling cylinders, even in groups, with a different speed in the module or the direction, to separate the oxide flakes, the difference in speed, between the speed of Advancement and roughing for sheet metal as well as the peripheral speed of the roll mill or the rolling mills activated with a different speed and from which the oxide flakes deposited on the conveyor series of the rolling mills themselves must be detached, is important. The difference in speed coupled with the friction between the conveyors generates force capable of causing the scraping 'between the conveyors and the roughing for sheet metal and in this way separates the oxide flakes from the conveyors themselves, until they fall on the bottom of the furnace 20 of rolling mills. With reference to Figures 3a, 3b, 4 and 5, these show a series of rolling cylinders 21 comprising a group of rolling cylinders 22 which are brought into contact with a blank 40 causing their movement. Said sheet metal 40 is conveyed by the group of rolling cylinders 22 and advanced in an advancing direction F to a rolling mill 60. The blank for sheet 40 has a rear portion 41 beyond the rolling mill 60, a central portion 43 and a portion initial 42 closer to the rolling mill 60. The rear portion 41 is transported by a group of rear rolling mills 31, the central portion of the cutting plate 40, on the other hand, is transported by a group of central rolling mills 33 while the of start is transported by a group of start rolling mills 32, respectively. During the movement of the slab 40, the rolling cylinders of the group of rolling cylinders 22 in contact with the slab 40 are obviously not the same. In addition, the rotation of each rolling mill cylinder of the series of rolling mills 21 can be activated with different rotation speeds and either with a direction in the direction or in an anti-clockwise direction, for the advance or braking of the roughing for sheet 40. In other words, the laminating cylinder cleaning system 10 is applied to a furnace 20 equipped with a series of motorized rolling cylinders 21, each of which in turn is connected to a relative motor 24 for rotational activation to its once connected to a relative frequency converter 25 driven by a rolling mill cleaner system 10 comprises a control and regulation unit 14 in order to independently control the speed of rotation and the direction of each rolling mill cylinder of the rolling mill series. 21 for the advancement of one or more slabs for sheet metal 40 and for the cleaning of at least one roll mill 34, which causes the detachment of the oxide flakes thereof by their scraping against the sheeting 40, by a variation in their speed of rotation or their direction. The laminating cylinder cleaning system 10 therefore preferably comprises a common field link 12 which connects the control and regulation unit 14 with each control and activation device. According to a first preferred embodiment of the process for cleaning the rolling mill rolls of a roll mill furnace 20, at least one roll mill 34 is a roll mill of the initial set of roll rolls 32, and step a) comprises: activation of the rotation of at least one rolling cylinder (34) of at least one group of rolling mills (22) with one module or a speed of direction which in turn will cause the scraping of at least one rolling cylinder (34) against the sheeting (40) so as to separate the oxide flakes of at least one rolling cylinder (34). ). The phase a) preferably considers the activation of the rotation of at least one rolling cylinder of the group of rolling cylinders 32 starting with a direction of rotation which opposes the advance of the roughing for sheet 40 in the direction F of advance towards the rolling mill 60, and the activation of the rotation of the remaining group of laminating cylinders 22 in contact with the plate blank 40 with a rotation speed which is such that it allows the blank for sheet 40 to advance in the F direction with a lower module speed in comparison with that of at least one rolling mill (34). At least one rolling cylinder 34 has a speed difference which is such as to cause scraping of the outer surface of at least one rolling cylinder 34 with respect to the sheeting 40 with the consequent detachment of the oxide flakes from the sheet. outer surface of at least one rolling cylinder 34, in particular of the contact surface of the series of conveyors of at least one rolling cylinder with the blank for sheet 40. In this case, the parameters which can be established by a operator of the control and regulation unit 14 are: percentage of decrease in the speed of the slab for sheet metal. The admitted range varies from 30 to 100% (100% = nominal speed of the roughing for sheet metal with the cleaning system not working); percentage of increase of countercurrent speed of the motor-cylinder rolling mill that is going to be cleaned, with respect to the speed of movement of the roughing for sheet metal. The admitted range varies from 0 to -130% (countercurrent rotation); limit of the current absorbed by the motorized rolling mills (measured in amperes). The admitted range must be limited to a maximum of 90% of the minimum value between: the maximum current which can be. supplied by the frequency converter and the maximum current that can be absorbed by the motor-cylinder laminator; range of use inside the furnace, which means the number of rolling cylinders on which the procedure is going to be applied; cleaning time of the motorized rolling mills. The period of time to carry out the cleaning can be established by the operator from 0 seconds up to the mechanical tolerance limit of the motorized rolling mills, which depends on each plant and is specified in the operation files. According to a second preferred embodiment of the method for cleaning the rolling mill rolls of a rolling mill furnace 20, at least one rolling cylinder 34 is the group of rolling mill rolls 32 and the phase a) preferably comprises: b) activating the rotation of the group of starter rollers 32 with a rotation speed which is such that the slab 40 is allowed to advance in the direction F; c) activating the rotation of the group of final rolling mills 31 and the group of central rolling mills 33 with a lower module speed compared to that of the group of rolling mills 32 at the start and with the same rotation direction: Phase c ) of the cleaning process preferably consists of: - activating the rotation of the group of central rolling mills 33 and the group of final rolling mills 31 with the same module and direction of rotation speed. Advantageously, it is possible to exert traction on the starting portion 42 of the slab 40 in its forward direction F, preventing the slab 40 from making a right-handed turn and also avoiding the possible scraping of the slab 40 on the part of the slab 40. the oxide flakes present in the series of conveyors of the series of laminating cylinders 22 in contact with the blank for sheet 40 itself. In this case, the parameters that can be established by an operator of the control and regulation unit 14 are: - percentage of motorized lathe cylinders coupled to the front of the sheet metal slab from which the speed is to be varied from the point of establishment; minimum quantity of motorized initial rolling mill cylinders coupled in the function; percentage of increase in speed, with respect to the nominal movement speed of the sheet metal slab. The admitted range varies from 100% to + 130% (100% = nominal speed of the blank for sheet metal); - limit of the current absorbed by the motorized rolling mills (measured in amperes). The admitted range must be limited to a maximum of 90% of the minimum value between: the maximum current which can be supplied by the frequency converter and the maximum current absorbed by the motor-cylinder rolling mill; selection of the number of slabs for a foundry sheet to which the system can be applied; activation of the function of slabs for sheet metal in the casting phase; activation of the function of slabs for sheet metal in the oscillating phase; activation of the function on the first slab for sheet metal in the casting phase; - activation of the function of the last roughing for sheet metal in the casting phase; interval of the internal use of the furnace, which means to determine the quantity of rolling mills to which the procedure will be applied. The phase c) of the cleaning process preferably consists of: activation of the group of central rolling mills 33 with a rotation speed of lower module compared with the rotation speed of the starting group of rolling mills 32; activation of the group of the final rolling cylinders 31 with a rotation speed of lower module compared to the rotation speed of the central group of rolling rolls 33. In this way, the cleaning of the rolling rolls 22 is carried out at the start and the end as a difference in speed with respect to the rotation speed of the central group of rolling cylinders 33 with a greater frictional force having a component tangent to the outer surface of the rolling cylinders which is such as to cause the scraping between each laminating cylinder of the final group of laminating cylinders 31 and the group of laminating cylinders 32, respectively, with the roughing for sheet 40, with the consequent detachment, by scraping, of the oxide flakes from the surface of the laminating cylinders , in particular of the outer contact surface of the series of conveyors with the plate 40 quarto. In this case, the parameters that can be established by an operator of the control and regulation unit 14 are: percentage of the motorized rolling mill cylinders coupled under the front part of the sheet metal cutting whose speed adjustment point is to be varied; minimum quantity of motorized front rolling mills coupled in the function; percentage of increase in speed, with respect to the nominal movement speed of the sheet metal slab. The admitted range varies from 100% to + 130% (100% = nominal feed speed of the blank for sheet metal); percentage of the motorized rolling mill cylinders coupled under the back of the slab for sheet metal whose speed setpoint will be varied; minimum quantity of motorized final rolling cylinders coupled in the function; percentage of speed reduction, with respect to the nominal movement speed of the sheet metal slab. The admitted range varies from 70% to + 100% (100% = nominal speed of the blank for sheet metal); limit of the current absorbed by the motorized rolling mills (measured in amperes). The admitted range must be limited to a maximum of 90% of the minimum value between: the maximum current which can be supplied by the frequency converter and the maximum current absorbed by the motor-motorized cylinder; - possibility of application of the initial motorized rolling mills only or only of the final motorized rolling mills; selection of the number of slabs for sheet metal from a foundry to which the system will be applied: activation of the function on slabs for sheet metal in the casting phase; activation of the function on the slabs for sheet metal in the oscillating phase; - activation of the function of the first slab for sheet metal in the casting phase; activation of the function of the last roughing for sheet metal in the casting phase; range of use inside the kiln, which means the number of rolling mills to which the procedure will be applied. From what has been described in the foregoing with reference to the figures, it is evident that a laminating roller cleaning system, according to the invention, is particularly useful and advantageous. In this way, the objective mentioned in the preamble of the description is obtained. The shapes of the roller cleaning system of the invention and also the materials can obviously differ from that shown for purposes that are only illustrative and not limiting in the drawings. The scope of protection of the invention is therefore defined by the appended claims.

Claims (7)

1. A rolling mill cleaning system for a furnace equipped with a series of motorized rolling mills, each of which in turn is connected to a motor and a relative reducer for activation of rotation, which in turn is connected to a converter Relative frequency driven by a respective control and activation device, the laminating cylinder cleaning system comprises a control and regulation unit for independently controlling the speed of rotation and the direction of each laminating cylinder of the series of motorized laminating cylinders for advancing one or more slabs for sheet metal and for cleaning at least one rolling mill which causes the separation of the oxide flakes thereof by scraping against the sheet metal slab with a variation in the speed of rotation or in the direction thereof.

2. Laminating cylinder cleaning system, as described in claim 1, characterized in that it comprises a common field link which connects the control and regulation unit with each control and activation device.

3. Process of cleaning rolling mills of a rolling mill furnace, comprising a series of rolling mills of which a group of rolling mills is connected to a roughing for sheet metal or a similar steel structure, the rotation of. each rolling mill cylinder can be activated independently of the remaining rolling rolls of the series of rolling mills by means of activation devices, characterized in that the roller cleaning process comprises the following steps: a) activating the rotation of at least one roller rolling mill of at least one group of laminating cylinders with a modulus or speed of direction which is such as to cause the scraping of at least one rolling cylinder against the sheeting so that it separates the oxide flakes from at least one cylinder rolling mill

4. Process for cleaning rolling mill rolls, as described in claim 3, characterized in that step a) comprises the following bases: activating the rotation of at least one rolling cylinder of the initial group of rolling mills with a rotation direction which is opposed to the advance of the slab to the rolling mill; activating the rotation of the remaining rolling mill rolls of the rolling mill group in contact with the sheet metal cutting with a rotation speed which is such that it causes the advance of the sheet metal cutting in the direction with a lower module speed compared with the of at least one rolling mill. Process for cleaning rolling mill rolls, as described in claim 3, characterized in that the series of rolling mill rolls comprises a group of rolling mill rolls in contact with the sheet metal cutting, which in turn comprises a group of start rolling mill rolls. , a group of final rolling mills and a group of central rolling mills, and wherein phase a) comprises the following steps: b) activating the rotation of the starting rolling mill group with a rotation speed which is such that sheet metal roughing is allowed to advance in the direction; c) activating the rotation of the group of final rolling mills and the group of central rolling mills with a lower module speed compared to that of the group of rolling mills at the start and with the same rotation direction. Process for cleaning rolling mill rolls, as described in claim 5, characterized in that step c) of the cleaning process consists of: activating the group of central rolling mills and the group of final rolling mills with the same module and direction of rotation speed. Method for cleaning rolling mill rolls, as described in claim 5, characterized in that step c) of the cleaning method consists of: activating the group of central rolling mill rolls with a lower module speed compared to that of the group of start rolling mills; activate the group of final rolling mills with a lower module speed compared to the group of central rolling mills.