Roller with shielding for the sensor

Abstract

A roller for a material web processing machine, wherein the roller includes a roller cylinder having a cylindrical roller core, a roller sleeve surrounding the roller core, and an outer cover, wherein the roller sleeve is composed of one or more roller sleeve layers in a radial direction, and the roller sleeve includes a plurality of sensors, characterized in that a conductive shield is arranged radially between these sensors and the outer cover; a material web processing machine including a sensor roller and a corresponding roller arranged parallel to the sensor roller, with a processing gap between the sensor roller and the corresponding roller, wherein each of the plurality of sensors of the sensor roller is capable of detecting pressure applied to the sensor roller when passing through the processing gap.

Description

Technical Field

[0001] The present invention relates to a roller for a material web processing machine and a material web processing machine including the roller. Background Technology

[0002] Documents WO 2013 / 104600 A1 and US 5,562,027 disclose rollers for paper machines equipped with multiple sensors for measuring pressure in the roll gap. Document WO 2013 / 104600 A1 discloses a fiber optic sensor, while document US 5,562,027 uses a conventional piezoelectric sensor. Document WO 2014 / 037016 A1 discloses a printed piezoelectric film for pressure detection. Document FI 12489 U1 discloses rollers for paper machines with sensor structures printed below the roll surface.

[0003] The technical problem to be solved by the present invention

[0004] In rollers equipped with sensors for detecting pressure, the quality of the read signal degrades under certain conditions. This occurs, for example, when the rollers form a roller pair with an intermediate processing gap and the pair is running in a dry state. The inventors discovered that this interference with signal quality is caused by static electricity buildup on the roller sleeve surface.

[0005] Therefore, the technical problem to be solved by the present invention is to provide a roller with an improved sensor system that can provide high-quality and reliable sensor readings even under harsh operating conditions. Summary of the Invention

[0006] The aforementioned technical problem is solved by providing a roller for a material web processing machine that includes a conductive shielding element, and a material web processing machine that includes the roller.

[0007] The technical solution of the present invention is defined in the following aspects:

[0008] [1] A roller for a material web processing machine, wherein the roller includes a roller cylinder having a cylindrical roller core, a roller sleeve surrounding the roller core and an outer cover, wherein the roller sleeve is composed of one or more roller sleeve layers in a radial direction and the roller sleeve includes a plurality of sensors, characterized in that a conductive shield is arranged in a radial direction between the sensors and the outer cover.

[0009] [1-1] According to aspect [1], the roller is wherein the sensor is arranged below the functional layer of the roller, wherein the thickness of the functional layer is preferably 3 mm to 40 mm.

[0010] [1-2] The roller according to aspect [1] or [1-1], wherein the material web processing machine is a paper web processing machine.

[0011] [1-3] The roller according to any one of the above aspects, wherein the length of the roller is 1 to 20 m, the diameter of the roller core is 5 to 100 mm, the thickness of the roller sleeve is 5 to 50 mm, the roller sleeve has 5 or more, preferably 10 or more sensors, and the thickness of the shield is 1 μm to 10 mm.

[0012] [2] The roller according to one of the above aspects, wherein the sensor is a pressure sensor.

[0013] [2-1] The roller according to aspect [2], wherein the sensor is a piezoelectric sensor.

[0014] [3] The roller according to one of the above aspects, wherein the sensor is arranged on the roller core or between two roller sleeve layers.

[0015] [4] The roller according to one of the above aspects, wherein the sensor is isolated from the shield by an insulating element.

[0016] [5] The roller according to any of the above aspects, wherein the sensor is applied as a sensor layer on the roller core, roller sleeve layer, insulating element or sensor film.

[0017] [5-1] The roller according to aspect [5], wherein the sensor layer comprises a sensor and an electrical conductor.

[0018] [5-2] The roller according to aspect [5] or [5-1], wherein the thickness of the sensor layer is from 1µm to 50µm.

[0019] [5-3] The roller according to any one of aspects [5] to [5-2], wherein the sensor is arranged on a shield and isolated from the shield by an insulating element.

[0020] [5-4] The roller according to any one of [5] to [5-3], wherein the shield is a metal foil, the insulating element is printed on the metal foil, and the sensor is printed on the insulating element.

[0021] [5-5] The roller according to aspect [5-4], wherein the thickness of the metal foil, the insulating element and the sensor are from 1µm to 50µm respectively.

[0022] [5-6] The roller according to any one of [5] to [5-2], wherein the sensor film is a polymer film.

[0023] [5-7] The roller according to aspect [5-6], wherein the thickness of the polymer film is 50µm to 3mm.

[0024] [6] The roller according to one of the above aspects, wherein the sensor is printed, or the sensor layer is printed.

[0025] [7] The roller according to any of the above aspects, wherein the shielding element comprises a metal-containing or carbon-containing material such that the shielding element is conductive.

[0026] [8] The roller according to any of the above aspects, wherein the shielding member is a roller sleeve layer, shielding film, shielding mesh or shielding layer containing conductive material, the shielding layer being applied to the sensor or to an insulating member applied to the sensor.

[0027] [8-1] The roller according to aspect [8], wherein the conductive material is a fabric or comprises fibers or particles, preferably carbon black particles or nanotubes, embedded in the roller sleeve layer.

[0028] [8-2] The roller according to aspect [8], wherein the thickness of the shielding film is from 1µm to 100µm.

[0029] [8-3] The roller according to aspect [8], wherein the shielding film is a metal foil with a thickness of 1µm to 50µm.

[0030] [8-4] The roller according to aspect [8], wherein the shielding layer covers the sensor and the adjacent area.

[0031] [9] The roller according to aspect [8] or [8-4], wherein the shielding layer is printed.

[0032] [9-1] The roller according to aspect [9], wherein the thickness of the shielding layer is from 1µm to 50µm.

[0033] [9-2] The roller according to aspect [9], wherein the sensor is printed on a sensor film, the insulating element is printed on the sensor, and the shielding layer is printed on the insulating element, wherein the thicknesses of the sensor, the insulating element and the shielding element are 1µm to 50µm, preferably 5µm to 40µm, respectively.

[0034]

[10] The roller according to one of the above aspects, wherein the roller core is conductive and in electrical contact with the shield.

[0035] [10-1] The roller according to aspect

[10] , wherein the shielding element contacts the roller core.

[0036] [10-2] The roller according to aspect

[10] or [10-1], wherein the roller core is electrically grounded.

[0037] [10-3] The roller according to any one of aspects

[10] to [10-2], wherein the shield is a shielding film or a conductive roller sleeve layer, and the sensor is isolated from the shield by an insulating element.

[0038]

[11] A roller according to any one of aspects

[10] to [10-3], wherein the shield is a thin film that extends beyond the roller and is in electrical contact with the roller core, or a plurality of sensors are arranged between the roller core and a conductive roller sleeve layer and the roller core and the conductive roller sleeve layer are in electrical contact between these sensors.

[0039] [11-1] The roller according to aspect

[11] , wherein the roller core extends longitudinally beyond the roller.

[0040]

[12] The roller according to one of the above aspects, wherein the signal generated in the sensor is transmitted to the sensor data unit via a signal line.

[0041] [12-1] The roller according to aspect

[12] , wherein the sensors are located at different positions in the circular direction of the roller.

[0042] [12-2] The roller according to aspect

[12] or [12-1], wherein a single signal line transmits signals from multiple or all sensors to the sensor data unit.

[0043]

[13] The roller according to one of the above aspects, wherein a position sensor for detecting the rotation angle of the roller is arranged on one end side of the roller.

[0044]

[14] The roller according to aspect

[13] , wherein the position sensor and the sensor data unit are arranged on the same end side of the roller and are interconnected by a data line.

[0045]

[15] A material web processing machine includes a roller as a sensor roller according to one of aspects [1] to

[14] and a corresponding roller arranged parallel to the sensor roller, wherein there is a processing gap between the sensor roller and the corresponding roller, wherein each of a plurality of sensors of the sensor roller is capable of detecting pressure applied to the sensor roller when passing through the processing gap.

[0046] Advantages of the present invention

[0047] The shielding element in the roller according to the invention improves the quality of the signal detected by the sensor inside the roller.

[0048] Embodiments of the present invention

[0049] In the following text, the roller for the material web processing machine according to the present invention is sometimes simply referred to as the "roller". Similarly, in the following text, the roller or component of the material web processing machine according to the present invention is sometimes simply referred to as the "sensor", "shielding component", etc.

[0050] The roller includes a roller cylinder having a cylindrical roller core, a roller sleeve surrounding the roller core, and an outer cover, wherein the roller sleeve is composed of one or more roller sleeve layers in a radial direction. The roller core is made of, for example, metal. The roller sleeve is made of, for example, polyurethane, rubber, composite materials, or fiber composite materials.

[0051] Rollers can be used for pressure detection in material web processing machines. Examples of material webs include nonwoven fabrics, woven fabrics, films, paper webs, or metal webs. This machine is suitable for the following material web processing applications:

[0052] • Coating processes, such as those used for encapsulation, especially in the photovoltaic field, packaging technology, especially food packaging, battery manufacturing, especially in the manufacture of anodes, cathodes and separators, OLED and optical coatings, as well as scratch-resistant coatings, dust-resistant coatings and electrostatic coatings;

[0053] • Adhesion process, coating process, calendering process;

[0054] • Lamination processes, for example, for manufacturing encapsulation, multilayer composites, PCB laminates, packaging or flexible packs, batteries and fuel cells, wire-wound capacitors, flexible electronic circuits and solar cells, displays, and medical applications, especially for manufacturing bandages or test strips.

[0055] • Surface mount technology (SMT) process, for example, used in the manufacture of electronic components;

[0056] • Grinding roller mill;

[0057] • Conveyor belts, for example, for recycling or sorting;

[0058] • Extrusion equipment, such as that used in film manufacturing;

[0059] • Printing processes, such as graphic printing, newspaper or paper printing, label printing, banknote printing, printed electronics, offset printing, gravure printing, flexographic printing, OLED and optical applications;

[0060] • Imprinting processes, such as nanoimprint lithography or thermal imprinting, especially for anti-reflective coatings;

[0061] • Optimizes material web operation, for example, for measuring material web tension or traction, or for vacuum coating, especially metal coating, and is also suitable for food;

[0062] • Finishing of textiles, especially through printing, coating or dyeing;

[0063] • Production of steel strips and metal strips;

[0064] • Condition monitoring of large substrates, especially wind turbines.

[0065] A paper machine, as an example of a material web processing device, can produce paper webs wider than 10m. This requires wider rolls because the rolls extend beyond the paper web on both sides. Roll pairs are used to process the paper web, with processing gaps between the roll pairs. These processing gaps can be press gaps for mechanical dewatering, calendering gaps for leveling, or coating gaps for pressing starch solution into the paper web to increase its strength.

[0066] At least one roller in the roller pair contains multiple sensors for pressure detection. Since it is typically necessary to detect the pressure distribution across the entire working width, multiple sensors can be fabricated on a sensor film at least as long as the roller and mounted on the roller.

[0067] Within the roller, sensors, insulators, and shielding components can be applied as coatings onto another layer or substrate. Here, "applied" refers to the application of the raw materials for the desired coating in a coatable form, such as a liquid or paste, followed by curing to form the desired coating. Coating can be performed by printing, vapor deposition, or spraying, with printing being the preferred method; therefore, "coating" here generally preferably refers to "printing." On the other hand, printed layers are used for simplicity only; these layers can also be coated using other processes.

[0068] Here, components may be described in the singular, such as "sensor layer" and "shielding element." These descriptions do not exclude plural forms, thus referring to "at least one sensor layer" or "at least one shielding element," respectively. Therefore, expressions such as "contains...sensor layer" and "contains...shielding element," or similar expressions, are synonymous with "contains...at least one sensor layer" or "contains...at least one shielding element." This rule also applies to other components of rollers or material web processing machines.

[0069] sensor

[0070] The roller includes, for example, 5 to 20 sensors. These sensors are distributed along the entire length of the roller. In other words, the sensors are positioned differently along the rotational axis of the roller. Furthermore, their positions along the circumferential direction of the roller may also vary. These sensors respond to changes in at least one environmental parameter, selected from the group consisting of pressure, temperature, and light intensity. Therefore, they can be pressure sensors, temperature sensors, and / or optical sensors, with pressure sensors being preferred. The pressure sensor can be a piezoelectric sensor.

[0071] The sensor can be embedded in the material of the roller sleeve layer, such as a polymer. However, it can also be coated onto a substrate as a thin sensor layer. The substrate is, for example, a thin film, preferably a flexible plastic film. For many applications, such as those in rotating rollers, the use of printed sensor layers has significant advantages. On the one hand, it is inexpensive to manufacture; on the other hand, due to its flat structure and the flexibility of the film, the sensor layer can be very firmly fixed to a curved roller without the risk of delamination. This risk is considerable for conventional sensors because they are subjected to significant continuous pressure during operation when the rollers form a compression gap with each other.

[0072] The sensor can be a layered sensor, comprising a first conductive layer, a ferroelectric polymer layer, and a second conductive layer, arranged in this order. Preferably, the ferroelectric polymer layer, the conductive layer, and the conductor can all be printed.

[0073] Shielding

[0074] The shielding component is conductive. Here, "conductive" also includes the meaning of "discharge." The shielding component is conductive in at least this way to prevent the formation of static charge in the composite, thereby achieving the desired goal of stable read signal quality. For example, the resistance of the shielding component is less than 10 Ω. 9 ohm.

[0075] The shield is arranged radially between the sensor and the outer cover. This means that the shield is arranged relative to the sensor in such a way that the shield and the sensor are cut by the same radial line in the circular cross-section of the roller.

[0076] Within the roller, electrostatic interference (ESI) is reduced both by the distance between the sensor and the roller surface and by conductive shielding. Since the thickness of the roller sleeve layer is typically between 15 mm and 30 mm, ESI can be effectively reduced by mounting the sensor on the roller core or on a layer below the roller surface. For example, a base layer of the roller sleeve layer with a thickness of 3 mm to 7 mm can be coated on the roller core. The sensor film can then be mounted on this base layer. The remaining portion of the roller sleeve can then be coated as a functional layer over the sensor film. The functional layer is the outermost layer of the roller's outer cover and is the surface in contact with the material web. The thickness of the functional layer is typically between 12 mm and 25 mm.

[0077] The distance between the shield and the sensor should be as small as possible to ensure maximum shielding effectiveness. For technical reasons, an insulating element must be provided between the shield and the electronic components of the sensor. Therefore, the required insulation thickness determines the minimum spacing. The shield can have any planar structure; it can be a continuous, non-perforated layer, or it can have a grid structure, mesh structure, or fabric structure. The shield is preferably designed as a shield, wherein the following embodiments (i) to (iv) may be adopted.

[0078] (i) The shielding element can be a thin film, formed, for example, by bonding or lamination. The film can be a metal foil, such as aluminum foil, or a film made of a conductive polymer. Examples of conductive polymers include PEDOT:PSS (PEDOT:PSS: poly(3,4-ethylenedioxythiophene):polystyrene sulfonate). Alternatively, for example, to reduce weight, a grid or mesh structure can be used instead of a continuous film.

[0079] (ii) The shielding element can be applied as a coating, for example, printed onto the substrate. If the electronic components themselves require printing, it is advantageous to print the shielding element simultaneously. In this case, the shape, size, and thickness of the shielding element offer great flexibility. For example, the shielding element may only need to be printed in the areas of the electronic components and wires. Printable materials may include conductive polymers, such as PEDOT:PSS, or printable metal nanowires, carbon, and / or silver. Furthermore, the coated shielding element may also be a layer composed of a conductive adhesive, such as an acrylate adhesive filled with silver nanoparticles, thereby additionally serving to firmly bond the two layers or two substrates.

[0080] (iii) The shielding element is based on a non-conductive material, i.e., a material comprising at least 50% by mass, more preferably at least 80% by mass. For example, the shielding element may be a polymer-based thin film in which a conductive material is embedded, thereby forming a shielding film that is conductive overall. Such materials include, for example, carbon nanotubes or conductive carbon black.

[0081] (iv) In a specific example of embodiment (iii), the shielding element may have additional functions besides shielding, which may be the primary function if necessary. For example, carbon fiber or metal wire may be incorporated as a fabric into the roller sleeve layer made of epoxy resin, wherein the fibrous material also imparts the strength necessary for the actual function of the roller sleeve layer.

[0082] The shielding element must at least cover the conductive elements of the sensor. Furthermore, the shielding element preferably extends laterally beyond these elements. For example, the shielding element protrudes beyond the sensor at least by the distance between the shielding element and the sensor. This is generally the case when using thin films. However, for shielding elements printed according to (ii), very thin and small-area shielding elements can also be manufactured. For example, an insulating layer with a thickness of 15µm is coated on a printed electronic component. The shielding layer is printed on this insulating layer. In this case, the width of the shielding layer should be sufficient to cover the electronic component and extend laterally beyond 15µm.

[0083] Shielding materials can be very thin. For example, aluminum foil with a thickness of 4µm to 20µm, especially 10µm to 15µm, is commercially available and is sufficient for shielding.

[0084] The insulating element is made of a material that electrically isolates the sensor from the shield. To achieve this function, the insulating element must have a higher electrical resistance than the shield. Examples of insulating materials include non-conductive polymers. Preferably, the insulating element is a printable layer. The insulating element can also be an adhesive layer, for example, used to connect a thin-film substrate printed with the sensor to the shield.

[0085] In one embodiment, the roller core is conductive, for example, metallic, and establishes electrical contact with a shield. The shield may be a thin film extending beyond the sensor or extending longitudinally beyond the roller and in electrical contact with the roller core. Alternatively, the sensor may be arranged between the roller core and the conductive roller sleeve layer, wherein the roller core and the conductive roller sleeve layer maintain electrical contact between the sensor. The roller core may be grounded.

[0086] Signal lines and position sensors

[0087] When the sensor passes through the processing gap, it generates a signal, which is transmitted via a signal line to the end of the roller. There, the sensor data unit processes the signal and, if necessary, transmits it to an external analysis unit. This sensor data unit is preferably mounted on the end, i.e., on the roller cover.

[0088] If the sensors are mounted parallel to the roller axis, all sensors will pass through the processing gap simultaneously. To correctly distribute signals to the corresponding sensors, each sensor requires an independent signal line. However, when using a large number of sensors, this results in an excessively wide sensor strip.

[0089] Therefore, it is preferable to wrap the sensor tape in a slightly helical shape around the roller or roller core, so that each sensor is positioned differently from the other sensors in both the axial and circumferential directions of the roller. Alternatively, the sensors are positioned differently along the rotational axis of the roller, and not all sensors are positioned identically in the circumferential direction. This ensures that at any given time, only a few sensors, especially only one sensor, pass through the processing gap, allowing multiple sensors to share the same signal line. In the case of the helical structure, all sensors can be connected to the data unit via the same signal line.

[0090] A further improvement of the present invention is to install a position sensor on one end of the roller to detect the rotation angle of the roller. This position sensor is preferably an optical sensor.

[0091] The position sensor and sensor data unit can be arranged on the same end side and interconnected via a data cable. The transmission unit located on the same end side can then transmit data determined based on the sensor signals, as well as data determined based on the position sensor signals, to the evaluation unit. This has the advantage of eliminating the need for additional modules, as all necessary components can be integrated into the signal data unit.

[0092] A material web processing machine may include a sensor roller and corresponding rollers arranged parallel to it, with a processing gap between them. Each sensor on the sensor roller can detect the pressure applied to the sensor roller as it passes through the processing gap. Based on the detection of the rotation angle of the sensor roller by a position sensor, the circumferential position of each sensor relative to the processing gap can be determined. The sensors can be arranged such that only one sensor passes through the processing gap at a time as the roller rotates. Preferably, the material web processing machine has a sensor roller with multiple corresponding rollers, wherein there are first and second processing gaps. Based on the detection of the rotation angle of the sensor roller by a position sensor, the circumferential position of each sensor relative to the first and second processing gaps can be determined. In this design, the sensors can also be arranged such that only one sensor always passes through the processing gap as the roller rotates.

[0093] The position sensor accurately determines which processing gap the sensor is currently passing through. Therefore, the correspondence between the sensor and the processing gap is clear and unambiguous. Importantly, multiple corresponding rollers are attached to the sensor roller. Example

[0094] In an embodiment of the invention, a roller is manufactured comprising, in sequence, a roller core, a plurality of sensors, a shield, and a roller sleeve outer cover. As the sensor layer, a thin-film substrate adhered to the roller core is used, on which pressure sensors and wires are printed; and as the shield, aluminum foil adhered to the sensor film is used.

[0095] In the comparative embodiment, the same rollers were manufactured, but aluminum foil was not used.

[0096] The roller was tested on a test bench, and pressure signals were collected. Compared with the control example, the signal quality measured on the roller according to the embodiment of the present invention was significantly higher, especially with improved clarity and no signal-to-noise ratio.

Claims

1. A roller for a material width processing machine, wherein, The roller includes a roller cylinder having a cylindrical roller core, a roller sleeve surrounding the roller core, and an outer cover, wherein the roller sleeve is composed of one or more roller sleeve layers in a radial direction, and the roller sleeve includes a plurality of sensors, characterized in that a conductive shield is arranged in a radial direction between the sensors and the outer cover.

2. The roller according to claim 1, wherein, The sensor is a pressure sensor.

3. The roller according to claim 1 or 2, wherein, The sensor is arranged on the roller core or between two roller sleeve layers.

4. The roller according to any one of the preceding claims, wherein, The sensor is isolated from the shield by an insulating component.

5. The roller according to any one of the preceding claims, wherein, The sensor is applied as a sensor layer on the roller core, roller sleeve layer, insulating component, or sensor film.

6. The roller according to any one of the preceding claims, wherein, The sensor is printed.

7. The roller according to any one of the preceding claims, wherein, The shielding component comprises a metal- or carbon-containing material, such that the shielding component is conductive.

8. The roller according to any one of the preceding claims, wherein, The shielding component is a roller sleeve layer, shielding film, shielding mesh, or shielding layer containing conductive material, and the shielding layer is applied to the sensor or to an insulating component applied to the sensor.

9. The roller according to claim 8, wherein, The shielding layer is printed.

10. The roller according to any one of the preceding claims, wherein, The roller core is conductive and in electrical contact with the shield.

11. The roller according to claim 10, wherein, The shielding element is a thin film that extends beyond the roller and makes electrical contact with the roller core, or multiple sensors are arranged between the roller core and a conductive roller sleeve layer, and the roller core and the conductive roller sleeve layer make electrical contact between the sensors.

12. The roller according to any one of the preceding claims, wherein, The signal generated in the sensor is transmitted to the sensor data unit via a signal line.

13. The roller according to any one of the preceding claims, wherein, A position sensor for detecting the rotation angle of the roller is arranged on one end side of the roller.

14. The roller according to claim 13, wherein, The position sensor and sensor data unit are arranged on the same end side of the roller and are interconnected by a data line.

15. A material web processing machine, comprising a roller as a sensor roller according to any one of claims 1 to 14 and a corresponding roller arranged parallel to the sensor roller, wherein a processing gap exists between the sensor roller and the corresponding roller, wherein, Each of the plurality of sensors on the sensor roller is able to detect the pressure applied to the sensor roller as it passes through the processing gap.