ROLLER PLANT WITH A WETTING DEVICE AND METHOD FOR OPERATION OF A ROLLER PLANT

Description

[0001] The present invention relates to a roller system used, for example, in the production and processing of a rubber or silicone material. This also includes rubber and silicone compounds. It could, for example, be a formulation for tires or other technical rubber or silicone products.

[0002] In such roller systems, material can adhere to the rollers. Previous solutions to prevent this adhesion include using optimized roller surfaces or temperature control, such as cooling. However, this often only has a short-term effect, so that after a few weeks, significant adhesion reappears. Consequently, the material must be manually removed from the rollers, leading to downtime and thus reduced production line efficiency.

[0003] From JP 2004 188458 A, a hot rolling mill for rolling steel is known in which a cleaning agent is applied to the backup rolls to remove lubricant and prevent slippage between the work rolls and backup rolls. JP 2002 254462 A discloses a rolling mill in which a small amount of steam is applied to a roll to prevent adhesion. DE 10 2007 042898 A1 discloses a method for roll gap lubrication in which a water-oil mixture is sprayed onto a roll and a cleaning medium in the form of hot water or steam is applied at defined intervals or depending on a process status. JP H09 201838 A discloses a rolling mill in which a liquid film is applied to a roll to prevent particles from adhering to the roll.US Patent 3,504,075 A discloses a method for producing polymer films using a cold rolling mill, in which a lubricant is applied between the roll and the polymer film to form a hydrodynamic wedge. German Patent DE 10 2008 050392 A1 discloses a method for lubricating rolls to compensate for unevenness in a rolled strip. WO 2013 / 120750 A1 discloses a method for lubricating a roll gap to improve the surface quality of the rolled material.

[0004] EP 3 722 005 A1 discloses a rolling mill for steel sheets in which the rolling rolls are cooled by means of cooling water supply parts and in which a surface condition of the rolling rolls is detected by observation devices, wherein the applied cooling water is removed locally at the position of the observation devices.

[0005] US Patent 2004 / 0035540 A1 describes a calender roll for the paper industry in which soiling on the roll is removed by wetting the roll with a liquid and the soiling being absorbed by the paper web.

[0006] It is an object of the present invention to provide an improved roller system, a use of a wetting device and a method for operating a roller system.

[0007] According to a first aspect of the present invention according to claim 1, a rolling mill comprises one or more rollers for rolling a material. In particular, the rolling process can shape and / or homogenize the material. For example, the rolling process forms a web from the material. For example, the rolling mill comprises several interacting rollers. The material can be drawn into a gap between the rollers.

[0008] The material consists, for example, of rubber or silicone and can also be a compound. A rolled sheet of the material is also called a "coat." This material is used to manufacture, for example, tires or other technical rubber or silicone products.

[0009] The roller system includes a wetting device for applying a liquid to at least one roller. The wetting is intended to reduce material adhesion to the roller.

[0010] The wetting device can be designed to wet all or at least several of the rollers. Alternatively, the wetting device can be designed to wet only one of the rollers, for example, a roller that is particularly prone to or specifically affected by adhesion.

[0011] Such a wetting device can be used during operation, eliminating the need to stop production to manually remove build-up. Furthermore, the wetting device ensures a long-term reduction in build-up. This increases plant availability and, consequently, production throughput.

[0012] The liquid can be water, especially pure water. It can also contain soap, for example, a water-soap mixture. Depending on the material being processed, other liquids, particularly anti-stick agents, can also be used. It is also possible to switch between different liquids during operation of the rolling mill. For example, a stronger anti-stick agent is used during critical phases of operation or when excessive adhesion is detected, compared to non-critical phases or when adhesion is not critical. For instance, a water-soap mixture can be used when starting up the rolling mill, followed by pure water. This ensures that excessive adhesion does not occur during a critical start-up phase and simultaneously reduces the consumption of soap or other chemicals.

[0013] For example, the liquid is drawn from a liquid tank or a pipeline. It is also possible that the liquid is drawn from a tank that is already present to prevent the rolled webs from sticking together. For example, the rolling mill has a batch-off unit for further processing the rolled webs, which contains such a tank.

[0014] The wetting device has, for example, one or more outlets through which the liquid is applied to the roller. The outlet is designed, for example, as a nozzle or sponge. The liquid is applied, for example, by spraying, vaporizing, or wiping onto the surface of the roller.

[0015] There can be multiple outlets. For example, there can be multiple outlets for wetting a single roller. There can also be multiple outlets for wetting multiple rollers. It is also possible to design one outlet to wet several rollers simultaneously.

[0016] The wetting device can include a control unit that regulates the wetting process. For example, the control unit can open one or more valves and activate conveying devices to transport the liquid to the outlet. The control unit can also stop the wetting process. Optionally, the control unit can be integrated into another control unit, such as the control unit of an extruder or a batch-off system.

[0017] The wetting device can be designed in such a way that wetting takes place continuously during the operation of the roller system. This allows adhesion to be prevented proactively and permanently.

[0018] The wetting device can also be designed so that wetting takes place at least at the start of a new material formulation or a new batch. This ensures that the processing starts smoothly, for example, that the material transfer to the batch-off system starts correctly. After an initial start-up phase, the wetting can be switched off or reduced. Alternatively, the wetting can remain constant throughout.

[0019] Alternatively, the wetting device can be designed such that wetting only occurs when adhesion actually takes place. This has the advantage of minimizing liquid ingress into the material and other problems that can occur with excessive wetting. Furthermore, liquid consumption can be minimized.

[0020] The wetting device has at least one adhesion sensor for detecting material adhesion to at least one of the rollers. For example, the adhesion sensor is designed as a light barrier. The light barrier is positioned such that it is interrupted when the material adheres to one of the rollers. The adhesion sensor can also be implemented, for example, by image capture and recognition or 3D scanning.

[0021] The adhesion sensor can be connected to a control unit of the wetting device. The control unit can be designed so that wetting occurs selectively only when adhesion is detected. For example, wetting is initiated when adhesion is detected and terminated as soon as it is detected that no further adhesion is present. This minimizes the influence of wetting on the material properties. It is also possible to increase or decrease the amount of liquid as soon as adhesion occurs or is reduced.

[0022] This approach is based on the premise that not every instance of adhesion leads to a critical disruption of the process flow. Adhesion may still be non-critical if the material is carried a short distance by the roller but then detaches before being drawn around it. The adhesion sensor can detect when the material adheres to the roller further than normal, but before the adhesion reaches a critical level, particularly before it is drawn around the roller. Thus, the adhesion sensor can identify the tendency toward increased adhesion at an early stage, allowing wetting to occur before a critical level of adhesion is reached.

[0023] It is also possible for the wetting device to be designed for continuous wetting during operation of the roller system. In particular, the wetting device can be controlled such that wetting only occurs when material is passing through the rollers. Thus, wetting does not only occur after adhesion has already occurred. It is also possible to repeatedly start and stop the wetting process at predetermined intervals. In this way, adhesion can be prevented proactively.

[0024] The wetting device can be designed for retrofitting existing systems. For this purpose, the wetting device can include a mounting element that allows it to be attached to an existing roller system. For example, an outlet of the wetting device is attached to a support of a roller.

[0025] The wetting device can have its own control unit. It is also possible for the wetting device to be connected to an existing control unit of the roller system, with the control unit equipped with a suitable algorithm for controlling the wetting device. In particular, the control unit can also be integrated into an existing control unit of a batch-off system.

[0026] The wetting device can include one or more adhesion sensors, which are also installed during a retrofit on the roller system. It is also possible that the roller system already has one or more adhesion sensors, the signal from which can also be used to control the wetting device.

[0027] With multiple rollers, several adhesion sensors can be present, each detecting adhesion on its own roller. The wetting device can be configured to initiate wetting only for the roller where adhesion is detected. Alternatively, multiple or all rollers can be wetted as soon as adhesion is detected on at least one roller. Adhesion on one roller can indicate that adhesion will soon occur on other rollers as well.

[0028] According to a further aspect of the present invention according to claim 11, a method for operating a roller system for rolling a material is specified. For example, a web of the material is produced in the method. Additionally or alternatively, the material can be homogenized in the method. The roller system has one or more rollers which are wetted with a liquid during operation to prevent the material from adhering to at least one of the rollers. This can be, in particular, the roller system described above. The wetting can be carried out by the wetting device described above.

[0029] According to the invention, the process monitors the adhesion of a material to the rollers. For example, an adhesion sensor is used for this purpose. The wetting process is controlled according to the invention, depending on the degree of adhesion. For example, the wetting process is only started when adhesion is detected. It is also possible to increase the amount of liquid when adhesion is detected.

[0030] Similarly, reduced adhesion can be detected. The wetting process can be stopped upon detection of reduced adhesion. It is also possible to reduce the amount of liquid used upon detection of reduced adhesion.

[0031] As previously described, if multiple rollers are present, several rollers can be wetted. It is also possible to wet only one roller, or only the roller most prone to adhesion or specifically affected. If adhesion is detected on one of the rollers, wetting can be initiated for that roller only, or for other rollers as well.

[0032] As described above, wetting can also take place continuously during operation or at fixed predetermined times.

[0033] The present invention comprises several aspects, in particular devices and methods. The features, properties and embodiments described for one aspect shall also apply accordingly to the other aspect.

[0034] Furthermore, the description of the items specified here is not limited to the specific embodiments. Rather, the features of the individual embodiments can be combined with one another – insofar as this is technically feasible. The items described here are explained in more detail below using schematic examples.

[0035] They show: Figure 1 shows an embodiment of a roller system in a schematic sectional view, Figure 2 shows an embodiment of a wetting device in a schematic circuit diagram, Figure 3 shows a method for operating a roller system in a schematic block diagram.

[0036] Preferably, in the following figures, the same reference numerals refer to functionally or structurally corresponding parts of the different embodiments.

[0037] Figure 1Figure 1 shows a schematic representation of a roller system 1. The roller system 1 is used to produce a sheet 2 from a material 3, such as rubber or silicone. This also includes rubber or silicone compounds. Such sheets 2 are also referred to as "faces." For example, they can be a formulation for tires or technical rubber or silicone products such as seals or molded parts. The roller system 1 can be used for mixing, homogenizing, shaping, and / or cooling the material 3. Embodiments are also possible in which a roller system is primarily used for mixing or homogenizing a material. The roller system can also be used in a first process step for mixing and / or homogenizing the material and in a further process step for producing a sheet 2 of the material.

[0038] The roller assembly 1 has two cooperating rollers 10, 11. The material 3 is fed to the rollers 10, 11 via a roller feeder 4, for example, an outlet of an extruder 5. The material 3 is drawn into a gap 12 between the rollers 10, 11 and formed into a flat sheet 2 by the rotating rollers 10, 11. It is also possible to incorporate embodiments in which the material 3 is fed gravimetrically from above to the rollers 10, 11.

[0039] The rollers 10, 11 can be heated or cooled. In this case, a first roller 10, in particular an upper roller, and a second roller 11, in particular a lower roller, are provided. Depending on the design of the roller assembly 1, these could, for example, also be a front roller and a rear roller. The roller assembly 1 can include further rollers. Such a system of interacting, superimposed rollers 10, 11 is also called a calander.

[0040] The web 2 produced by the interacting rollers 10, 11 is transported via a conveyor belt 6 and fed to a batch-off system 7. In a rolling mill, for example, a web 2 can also be removed only after a mixing process using the same rollers 10, 11. The batch-off system 7 serves for the further processing of the web 2. For example, the batch-off system 7 has a tank 8 filled with an anti-stick agent. This could be, for example, a mixture of water and soap ("anti-tack"). The anti-stick agent is applied to the web 2 to prevent sticking. For example, the web 2 is drawn through the anti-stick agent in the tank 8 or sprayed with the anti-stick agent. The batch-off system 7 can have a drying chamber 9 in which the web 2 is dried and cooled.

[0041] With some materials 3, especially modern blends, undesirable and detrimental adhesion of the material 3 to the rollers 10, 11 can occur. This can lead to unplanned downtime and thus to reduced efficiency of the production line. It is possible that in a first process step, for example, a mixing operation, adhesion to one or more of the rollers 10, 11 is permitted or even desired, while in a subsequent process step, for example, the removal of a web 2, such adhesion is detrimental.

[0042] To reduce or eliminate unwanted adhesion to the surfaces of the rollers 10, 11, the roller system 1 has a wetting device 13 that wets at least one of the rollers 10, 11 with a liquid. The liquid is, for example, water or an anti-stick agent such as a water-soap mixture ("antitack"). The anti-stick agent is, for example, taken from tank 8 of the batch-off system 7 via a feeder 24.

[0043] The liquid can be sprayed or vaporized. Thus, applying the liquid implies that it is in vapor form during the application process. It is also possible to apply the liquid to the rollers 10, 11 using a sponge. The wetting device 13 has one or more outlets 14, 15 for this purpose. Depending on the application method, the outlets 14, 15 are designed, for example, as nozzles or sponges. In this case, a first outlet 14 is arranged on a first roller 10 and a second outlet 15 on a second roller 11, and both serve to apply the liquid to the respective rollers 10, 11. The outlets 14, 15 can be arranged, as shown, on the side of the material feed to the rollers 10, 11. The outlets 14, 15 can, for example, also be arranged on the opposite side, i.e., on the side of the material exit from the rollers 10, 11.

[0044] The wetting device 13 can continuously apply a liquid to the rollers 10, 11 during operation. However, the wetting device 13 can also be configured to apply a liquid only when needed, i.e., when material 3 actually adheres to one of the rollers 10, 11. It is also possible that the amount of liquid is increased upon detection of adhesion and / or decreased upon detection of a decrease in adhesion.

[0045] In the embodiment shown, the wetting device 13 has at least one adhesion sensor 16, 17 for detecting adhesion of the material 3 to the rollers 10, 11. In particular, a first adhesion sensor 16 is configured to detect adhesion to the first roller 10 and a second adhesion sensor 17 is configured to detect adhesion to the second roller 11.

[0046] The adhesion sensors 16, 17 are designed, for example, as light sensors, in particular in the form of light barriers. Alternatively, the adhesion sensors 16, 17 can also be implemented, for example, via image acquisition and image recognition or 3D scanning. Upon detection of adhesion of the material 3 to one of the rollers 10, 11, a signal can be sent to a control unit 18 (see Figure 2 ) will be sent.

[0047] Figure 2 Figure 1 shows a schematic circuit diagram of an embodiment of a wetting device 13. It may in particular be the device in the roller system 1 made of Figure 1 Wettening device 13 is used.

[0048] The wetting device 13 includes a control unit 18 that receives signals from the adhesion sensors 16, 17 and controls the wetting process. In particular, the control unit 18 can selectively control the dispensing of the liquid from the outlets 14, 15. If the control unit 18 receives a signal from one or both adhesion sensors 16, 17 indicating the presence of adhesion, it initiates the wetting of one or both of the rollers 10, 11. The control unit 18 can initiate the wetting of only the roller 10, 11 on which unwanted adhesion is detected. Alternatively, it can initiate the wetting of both rollers 10, 11 even if unwanted adhesion is detected on only one of them.

[0049] To initiate the wetting process, the control unit 18 sends a signal to one or more valves 19, 20, which are then opened. The valves 19, 20 can also be designed as proportional valves, allowing the dispensed liquid quantity to be adjusted. The valves 19, 20 can be individually controlled via separate control units 21, 22. Alternatively, the valves 19, 20 can be opened via a common control unit, enabling wetting of both rollers 10, 11 independently of which roller 10, 11 is being wetted.

[0050] The wetting fluid can, for example, be taken from tank 8 of the batch-off system 7. A supply line 24 from tank 8 can therefore be provided. Additionally or alternatively, the fluid can also be water, especially pure water, and a supply line 25 from a water tank or pipe can be provided. It is also possible to change the wetting fluids during operation. For example, a water-soap mixture can be used for wetting during a start-up phase, and later pure water. For example, as soon as excessive adhesion is detected, the system can switch back to the water-soap mixture. It is also possible to recycle excess wetting fluid.

[0051] If necessary, the liquid is conveyed via a conveying device 23, such as a pump. The conveying device 23 can be controlled by the control unit 18. If the liquid pressure is sufficient, the liquid can also reach the outlets 14, 15 without a conveying device 23 when the valves 19, 20 are opened.

[0052] If the adhesion sensors 16, 17 detect that no or only minimal adhesion is occurring, the wetting process can be stopped. Specifically, the adhesion sensors 16, 17 can send a corresponding signal to the control unit 18, which then switches off the optionally available pumping device 23 and closes the valves 19, 20. It is also possible to provide a liquid reservoir, such as a bladder reservoir, which immediately releases a wetting fluid when the valves 19, 20 are opened. Thus, the liquid reservoir can bridge the time required to start the pumping device 23 and / or reduce the activation intervals of the pumping device 23.

[0053] The wetting device 13 can be part of a roller system 1, or a roller system 1 can be easily retrofitted with the wetting device 13. For example, one or more outlets 14, 15 are attached to a housing of the roller system 1 near the one or more rollers 10, 11.

[0054] It is also possible that a retrofitted roller system 1 is already equipped with adhesion sensors 16, 17 for detecting adhesion. A control unit 18 may also already be present, which processes the signal from the adhesion sensors 16, 17 and is originally configured to stop the rollers 10, 11 as soon as excessive adhesion is detected. When the roller system 1 is retrofitted with a wetting device 13, the control unit 18 can be reprogrammed so that, instead of stopping the rollers 10, 11, it starts the wetting process. The rollers 10, 11 are then only stopped, for example, if the wetting process does not achieve the desired result within a few seconds.

[0055] Thus, for retrofitting, outlets 14 and 15 can be attached to an existing roller system 1 and connected to an existing control unit 18. Additionally, valves 19 and 20 and feeds 24 and 25 are connected to a liquid tank or line via outlets 14 and 15 and the control unit 18.

[0056] Figure 3 The block diagram shows a procedure for operating a rolling mill, for example rolling mill 1. Figure 1 The reference numbers used to describe the process refer to the roller plant 1 from Figure 1 , however, the procedure is not limited to the specific roller plant 1.

[0057] The roller system 1 is started. A material 3, in particular a material mixture, is fed to one or more rollers 10, 11. The wetting device 13 can be put into a ready mode when the roller system 1 is started.

[0058] In step A, it is monitored whether the material 3 adheres to one of the rollers 10, 11. Both rollers 10, 11 or only one of the rollers 10, 11 can be monitored using one or more adhesion sensors 16, 17.

[0059] If adhesion is detected ("y"), in step B, the wetting of one or more of the rollers 10, 11 with a liquid, for example a water-soap mixture, is initiated. Alternatively, the wetting can already be underway, and the amount of liquid is increased if adhesion is detected. If no adhesion is detected ("n"), no change in the wetting takes place, and the monitoring in step A continues.

[0060] In step C, if an adhesion is detected ("y"), it is monitored whether the adhesion is reduced or terminated.

[0061] If no or only minimal adhesion is detected ("y"), the wetting process is switched off again in step D, or the amount of liquid is reduced. Self-optimization can then be performed to apply an optimal amount of liquid to prevent adhesion. Otherwise ("n"), the adhesion status continues to be monitored.

[0062] After switching off the wetting or reducing the amount of liquid, it is monitored again in step A whether adhesion occurs.

[0063] Alternatively, wetting can be continuous or switched on and off at predetermined times, thus preventing adhesion as a precautionary measure. For example, wetting can begin at startup or even before the actual start of the rolling mill 1 and then be reduced or switched off later. If adhesion is desired in the first process step of the rolling mill 1 and undesired in a second process step, wetting can also be initiated, for example, only with the second process step. Upon detection of adhesion, wetting and monitoring can then take place as described above.

[0064] For example, wetting occurs continuously as long as material 3 is located between rollers 10 and 11. In particular, it can be detected whether material 3 is in the extruder 5 and will therefore soon be fed to the rollers 10 and 11. Detection is achieved, for example, by the motor current of a drive for the extruder 5, via load cells on the extruder 5, or via a temperature sensor or mass pressure sensor at the roller feed 4. Wetting can then be started.

[0065] Furthermore, it can be detected whether the material 3 has completely passed through the rollers 10, 11, so that no material remains between them. Such detection is achieved, for example, via a sensor on the conveyor belt 6, such as an ultrasonic sensor, by monitoring the operating time, or by counting the number of revolutions of the rollers 10, 11. Detection via a temperature sensor or a mass pressure sensor is also possible. Upon successful detection, the wetting process can be terminated. Reference symbol list

[0066] 1 Roller system 2 Track 3 Material 4 Roller feed 5 Extruder 6 Conveyor belt 7 Batch-off system 8 Tank 9 Drying chamber 10 Roller 11 Roller 12 Gap 13 Wetting device 14 Outlet 15 Outlet 16 Adhesion sensor 17 Adhesion sensor 18 Control unit 19 Valve 20 Valve 21 Control 22 Control 23 Conveyor 24 Feed 25 Feed

Claims

1. A rolling mill, comprising one or more rolls (10, 11) for rolling a material (3) in order to form a sheet from the material (3), and comprising a wetting device (13) for applying a liquid to at least one of the rolls (10, 11) in order to reduce adhesion of the rolled sheet of the material (3) to the roll (10, 11), comprising a control unit (18) for controlling the wetting and comprising at least one adhesion sensor (16, 17) for detecting adhesion of the rolled sheet of the material (3) to at least one of the rolls (10, 11), wherein the control unit (18) is configured to receive signals from the adhesion sensor (16, 17) and to use them for controlling the wetting apparatus (13).

2. The rolling mill according to one of the preceding claims, which is suitable for rolling a rubber or silicone material.

3. The rolling mill according to one of the preceding claims, comprising at least two interacting rolls (10, 11), wherein a gap (12) for drawing in the material (13) is formed between the rolls (10, 11).

4. The rolling mill according to Claim 3, wherein the wetting apparatus (13) is configured for wetting both of the two interacting rolls (10, 11).

5. The rolling mill according to one of the preceding claims, in which the wetting apparatus (13) has at least one outlet (14, 15) for application of the liquid to the rolls (10, 11), wherein the outlet (14, 15) is in the form of a nozzle or sponge.

6. The rolling mill according to one of the preceding claims, in which the adhesion sensor (16, 17) is in the form of a light barrier, an image-recognition device or a 3D-scanning device.

7. The rolling mill according to one of the preceding claims, in which the wetting apparatus (13) is configured to wet the rolls (10, 11) only if adhesion is detected.

8. The rolling mill according to one of Claims 1 to 6, in which the wetting apparatus (13) is configured such that the rolls (10, 11), during operation, are wetted continuously or are wetted only at defined times.

9. The rolling mill according to one of the preceding claims, in which the wetting apparatus (13) is suitable for applying a liquid in the form of water or a water / soap mixture.

10. The rolling mill according to one of the preceding claims, wherein the wetting apparatus (13) is configured to apply the liquid to the rolls (10, 11) by vapour deposition.

11. Method for operating a rolling mill (1) for rolling a material (3) in order to form a sheet from the material (3), wherein the rolling mill (1) has one or more rolls (10, 11), wherein, during operation, the rolls (10, 11) are wetted with a liquid in order to reduce adhesion of the rolled sheet of the material (3) to at least one of the rolls (10, 11), wherein adhesion of the rolled sheet of the material (3) to the rolls (10, 11) is monitored, wherein the wetting is controlled according to the adhesion.

12. Method according to Claim 11, wherein the wetting is started if excessive adhesion is detected, or wherein an amount of liquid for wetting is increased if excessive adhesion is detected.

13. Method according to either of Claims 11 or 12, comprising a control unit (18) for controlling the wetting and comprising at least one adhesion sensor (16, 17) for detecting adhesion of the rolled sheet of the material (3) to at least one of the rolls (10, 11), wherein the control unit (18) is configured to receive signals from the adhesion sensor (16, 17) and to use them for controlling the wetting apparatus (13).

14. Method according to one of Claims 11 to 13, wherein adhesion of the rolled sheet of the material (3) to the rolls (10, 11) is monitored, wherein, upon detection of a reduction in adhesion, the wetting is ended, or wherein an amount of liquid for wetting is reduced after detection of a reduction in adhesion.

15. Method according to one of Claims 11 to 14, wherein, during operation, it is switched between different liquids.