Apparatus for dewatering or cleaning a fabric in a paper machine, and a paper machine comprising such an apparatus

Abstract

The present invention relates to an apparatus for dewatering or cleaning a fabric in a paper machine, the apparatus (1) comprising: a contact portion (2) arranged on a first side of the apparatus (1) for contacting the fabric within the paper machine; an air device (4) for transporting air to or from the fabric, the air device (4) being operatively connected to at least one opening (3) in the first side for supplying or removing air through the at least one opening; a vibrator (5) operatively connected to the contact portion and configured to cause vibration of the contact portion during operation of the apparatus; and The present invention also relates to a paper machine (100, 100') comprising at least one such apparatus.

Description

Technical Field

[0001] The present invention relates to an apparatus for dewatering or washing a fabric in a paper machine, and a paper machine equipped with such an apparatus. In particular, the paper machine may be a machine for manufacturing tissue paper.

Background Art

[0002] A paper machine typically operates by injecting a base paper into the forming gap of a forming section, creating a paper web that passes through various sections to be formed, dewatered, dried, and optionally structured to form a finished paper. The paper web is transported on a series of wires or fabrics, such as felts, that are arranged in an endless loop and serve to form and protect the paper web and, optionally, also generate a structure in the paper web.

[0003] Since the base paper usually has a moisture content of about 97%, the main purpose in paper manufacturing is to remove water, which is done by a combination of pressing, suction, and heating. In some sections of the paper machine, water and air are transported through the wires or felts to suck water from the paper web or to allow air currents or hot air to reach the paper web. Some pulp fibers from the paper web may be trapped in or remain on the felt or wire after the paper web is transferred to further sections of the paper machine, and for this reason, a cleaning device is provided to help clean and dry them while they return to the point where they pick up the paper web again.

[0004] Current wire and felt cleaning devices have problems such as high energy consumption for removing water in order to sufficiently dry the wires and felts so that they can receive the paper web. Also, it is difficult to completely clean the wires and felts and remove all remaining pulp fibers in a short time until the paper web is picked up.

[0005] Dehydrating and drying the paper web is also troublesome, and due to the high cost and high energy consumption for heating steam and air, it is highly desirable to remove as much water as possible before the drying stage involving hot air or heating rolls.

[0006] Therefore, improvements are needed both in the cleaning of the wire and felt and in the dehydration of the paper web.

Summary of the Invention

[0007] The object of the present invention is to solve or at least minimize the above-mentioned problems. This is achieved by an apparatus for dehydrating or cleaning a fabric in a paper machine according to the appended independent claims, and a paper machine equipped with such an apparatus.

[0008] The apparatus of the present invention comprises a contact portion arranged on a first side of the apparatus for contacting a fabric within a paper machine, an air device for transporting air to or from the fabric, the air device being operatively connected to at least one opening on the first side for supplying or removing air through the at least one opening, and a vibration generator operatively connected to the contact portion and configured to cause vibration of the contact portion during operation of the apparatus.

[0009] By causing vibration of the contact portion, water and remaining pulp fibers are loosened from the fabric and are more easily removed by an air device that supplies pressurized air or vacuum, so that cleaning or dehydration is performed more efficiently. This achieves a more complete cleaning and can remove the remaining pulp fibers, making the cleaning of the fabric significantly more efficient. At the same time, when this apparatus is used for dehydrating the fabric that conveys the paper web, the dehydration is significantly improved, so that significant savings can be achieved both in terms of cost and energy consumption. This is because both the dryness of the paper web can be increased with fewer dehydration devices used and the amount of residual moisture that must be removed by hot air or steam is reduced.

[0010] At least one opening is arranged at the downstream end of the first side surface, and it is appropriate for the contact part to be arranged at the upstream end of the first side surface. Thereby, since air suction or blowing is performed immediately after vibrating the fabric, the water loosened by the vibration and optionally paper fibers are immediately removed.

[0011] Alternatively, at least one opening is arranged at the upstream end, and the contact part is arranged at the downstream end of the first side surface. Thereby, the suction or blowing affects the fabric immediately before the fabric vibrates, and the vibration of the fabric propagates from the contact point with the contact part to loosen the water and optionally pulp fibers, so it is very efficient in removing the water and optionally pulp fibers.

[0012] In another alternative form, at least one opening is arranged in the contact part so that air is supplied to or removed from the fabric through the contact part. Thereby, suction or blowing is performed exactly at the place where the vibration is transmitted to the fabric, which is very efficient in removing water and optionally residues adhered to or trapped in the fabric.

[0013] In some embodiments, the device has only one opening, but in other embodiments, a plurality of openings are provided, and they may be arranged not only within the contact part itself but also upstream and / or downstream of the contact part. It is very advantageous to provide one or more openings near the contact part so that water and optionally residues are removed at locations where the amplitude of the vibration is large.

[0014] In some embodiments for dehydration or washing, the air device is a suction device for sucking air from the fabric into the opening. This is also advantageous when the fabric conveys a paper web, because it provides efficient suction combined with vibration without damaging the paper web. This helps to increase the amount of water removed compared to conventional suction devices such as Uhle boxes.

[0015] In another embodiment for cleaning the fabric, the air device is an air knife for blowing air from the opening onto the fabric. This is advantageous for completely cleaning the fabric because the remaining residues are blown away with the water, and the combination of the air knife and vibration significantly improves over known air knives.

[0016] The vibration generator is suitably configured to operate at a frequency of at least 10 kHz, preferably at least 15 kHz, more preferably at least 20 kHz. Thereby, the contact portion vibrates at an appropriate frequency that is easily transmitted to the fabric.

[0017] The vibration generator may be configured to cause an amplitude of the contact portion of at least 10 μm, preferably at least 15 μm, more preferably at least 20 μm during operation of the device. In some embodiments, the amplitude may be as large as 50 μm. Thereby, the fabric vibrates and water is efficiently removed. It is advantageous because the larger the amplitude, the better the removal of water from the fabric.

[0018] The device may also include at least two contact portions, and the vibration generator may be operatively connected to each of the contact portions and configured to vibrate them independently of each other. This is advantageous for providing a more robust device with a longer lifespan because vibration of one contact portion can be generated even if the vibration of other contact portions malfunctions or fails. Also, the frequency and / or amplitude of the contact portion can be changed to enhance the efficiency of removing water from the fabric. A further advantage is that multiple contact portions and multiple openings can remove water more efficiently than a single contact portion with a single opening.

[0019] In some embodiments, the contact portion is a cylinder, preferably a TAD cylinder for a paper machine, and a plurality of openings are arranged in the contact portion to enable air transport through the contact portion. Thereby, the advantages of the present invention are achieved by vibrating the surface of the TAD cylinder.

[0020] The present invention also relates to a paper machine comprising a device as defined above. Thereby, compared with known prior art solutions, it becomes possible to more efficiently remove water from the fabric with high energy efficiency and cost efficiency. The paper machine according to the present invention comprises at least one device according to the present invention, but may optionally comprise a plurality of devices used for dehydration and / or washing or both.

[0021] It is appropriate that at least one device is arranged in the forming section of the paper machine and is configured to dehydrate the first fabric that conveys the paper web. Thereby, dehydration in the forming section is improved, and the moisture content of the paper web becomes lower when it is transferred to the subsequent section.

[0022] At least one device may be arranged in the press section of the paper machine and configured to dehydrate the second fabric that conveys the paper web. Thereby, dehydration in the press section is improved, and subsequent washing and optionally drying are also improved.

[0023] It is appropriate that at least one device is arranged in the structuring section of the paper machine and is configured to dehydrate the third fabric that conveys the paper web. Thereby, dehydration in the structuring section is improved, and the moisture content decreases until the final drying stage.

[0024] In some embodiments, the structuring section is a through-air drying section, a TAD. Thereby, the combination of structuring and drying is improved, and the need for heated air can be reduced.

[0025] It is appropriate that at least one device is arranged in the drying section of the paper machine and is configured to dehydrate the fabric that conveys the paper web. Thereby, the removal of the residual moisture of the paper web becomes more efficient, and the consumption of steam or hot air is reduced.

[0026] At least one device is suitably arranged in a cleaning section for cleaning the fabric. Thereby, the cleaning of the fabric is improved as compared to the cleaning sections of the prior art.

[0027] Many further benefits and advantages of the present invention will be readily understood by those skilled in the art upon consideration of the following detailed description.

[0028] Next, the present invention will be described in more detail with reference to the accompanying drawings.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2a

Figure 2b

Figure 3a

Figure 3b

Figure 3c

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0030] All the figures are schematic and not necessarily to scale. Generally, only the parts necessary to illustrate each embodiment are shown, and other parts may be omitted or merely suggested. Any reference numbers appearing in multiple drawings refer to the same object or feature throughout the drawings unless otherwise indicated.

[0031] In the context of the present invention, the term "fabric" is used to refer to any wire, band, structured fabric or belt used in a papermaking machine for forming or transporting a paper web. Such bands or belts include wires such as forming wires and structured wires, and also felts and other fabrics used in papermaking machines.

[0032] A papermaking machine is used herein to refer to any machine suitable for manufacturing paper from pulp. Such machines include, but are not limited to, machines for manufacturing tissue paper, paper, and cardboard.

[0033] When it is stated herein that two components are operatively connected to each other, this is to be understood as meaning that the components are connected to each other such that a signal, movement, or force can be transmitted from one to the other. Thus, when it is said that a vibration generator is operatively connected to a contact part, it should be understood that the vibration generator can vibrate the contact part.

[0034] The terms "upstream" and "downstream" are used herein with respect to the direction of movement of the fabric or paper web in a papermaking machine. Thus, a location upstream of another location is the location through which any given point on the fabric or paper web passes before reaching the other. The terms "front" and "back" are used to indicate that any given point on the fabric or paper web passes the "front" position of the other at an earlier time than the "back" position of the other.

[0035] A paper web is defined as pulp fibers that move together over a fabric to form a continuous web from the forming nip where the paper web is formed by a pulp suspension to the roll section where the paper web arrives as finished paper. "Captured residue" or simply "residue" is used to indicate the substances or particles of the paper web that remain within or on the fabric after the paper web has been transferred to a subsequent section of the papermaking machine. Such substances or particles include, among others, adhesives, coating agents, dirt, pulp fibers, and the like.

[0036] Hereinafter, the present invention will be described with reference to an embodiment of the apparatus schematically shown in FIG. 1, and the preferred embodiments shown in FIGS. 2a to 2b will be described. Next, a papermaking machine according to the present invention will be described with reference to two embodiments showing different manufacturing methods of paper, particularly tissue paper. It should be noted that the present invention can be used in any type of papermaking machine.

[0037] FIG. 1 discloses an apparatus 1 for dehydrating or washing a fabric according to the present invention. The apparatus 1 includes a contact portion 2 disposed on a first side A of the apparatus 1, and the first side A is a surface intended to face the fabric F within the papermaking machine. The fabric F is schematically disclosed in FIG. 2, and the moving direction D of the fabric F is indicated by an arrow pointing to the left side of the figure.

[0038] The contact portion 2 is operatively connected to a vibration generator 5 configured to cause vibration of the contact portion 2 during use of the apparatus 1. The vibration generator 5 is shown as being connected to the contact portion 2 by a connection portion 5', but in some embodiments, the vibration generator 5 may be integrated with the contact portion 2 or may be arranged to contact the contact portion 2 without the connection portion 5'. The vibration generator 5 is appropriately connected to a power source (not shown). The apparatus 1 also appropriately includes a housing 6 in which at least some of the components of the apparatus 1 are disposed.

[0039] The contact portion 2 may extend along the entire length l of the device 1 on the first side surface A of the device 1. However, in other embodiments, it may include only a portion of the length l. Also, in some embodiments, the contact portion 2 extends across the entire width w of the device 1, but in other embodiments, it may include only a portion of the width w. The length l is defined as the extension of the device 1 on the first side surface A in the moving direction of the fabric F, and the width w is the extension of the device 1 on the first side surface A in the direction perpendicular to the length l. FIG. 1 discloses the length l of the device 1, while FIG. 2a shows both the length l and the width w.

[0040] In some embodiments, the contact portion 2 is a single part of the device 1. However, in other embodiments, the device 1 may comprise a plurality of contact portions 2 individually or jointly connected to the vibration generator 5.

[0041] The device 1 further comprises an air device 4 for transporting air to or from the fabric F, and at least one opening 3 for supplying or removing air on the first side surface A. The at least one opening 3 can be any of the openings of the contact portion 2, upstream of the contact portion 2, downstream of the contact portion 2, or a combination of these options. In some embodiments, there may be at least one opening 3 beside the contact portion 2, parallel to the contact portion 2, that is, in a direction transverse to the moving direction D of the fabric F. It should be noted that in most embodiments, a plurality of openings 3 are arranged on the first side surface A, but a single opening 3 is also possible within the scope of the present invention.

[0042] When at least one opening 3 is arranged upstream US of the contact portion 2, the contact portion 2 is downstream DS of the at least one opening 3, and vice versa.

[0043] The first side A of the device 1 may comprise both the housing 6 and the contact portion 2, and at least one opening 3 is an opening provided in the first side A by extending through the housing 6 or through the contact portion 2 into the device 1. When a plurality of openings 3 are provided, these may be openings 3 provided in the housing 6, openings 3 provided in the contact portion 2, or both.

[0044] In some embodiments (see FIGS. 2a to 2b), the first side A of the device may comprise only the contact portion 2, and at least one opening 3 is an opening provided in the first side A by extending through the contact portion 2 into the device 1.

[0045] The air device 4 is connected to at least one opening 3 by an air connection 4', suitably a tube or conduit, such that air can pass between the air device 4 and the opening 3. The device 1 may also comprise a transport connection 4", which may suitably be a tube or conduit for transporting air between the air device 4 and a separate unit (not shown).

[0046] In some embodiments, the air device 4 is a suction device such as an Uhle box that generates a negative pressure (commonly called a vacuum), thereby operating by sucking air into the opening 3 leading to the air device 4. In such embodiments, the transport connection 4" may lead to a receiving container for receiving air together with water, residues, and optionally other substances such as dirt or particles from the fabric F. The air device 4 suitably generates a negative pressure of at least 10 kPa, more suitably at least 30 kPa, and even more suitably at least 65 kPa.

[0047] In other embodiments, the air device 4 is instead an air knife that operates by blowing pressurized air through at least one opening 3. In such an embodiment, the transport connection 4” may be connected to a source of pressurized air. The pressurized air is suitably supplied at a pressure of at least 0.5 bar, more suitably at least 5 bar, and even more suitably at least 10 bar. Higher pressures are advantageous for improving the removal of water and optionally residues from the fabric.

[0048] The vibration generator 5 is configured to vibrate the contact portion 2, thereby generating vibrations in the fabric F as the fabric F passes through the device 1 during operation. In some embodiments of the papermaking machine, the device 1 is configured to contact the fabric F, but in other embodiments, the device 1 may instead be arranged close to the fabric F such that the vibration of the contact portion 2 contacts the fabric F or the vibration of the contact portion 2 close to the fabric F also vibrates the fabric F. The vibration generator 5 is suitably configured to operate the contact portion 2 at a frequency of at least 10 kHz, preferably at least 15 kHz, and more preferably at least 20 kHz. The higher the frequency, the more vigorously the fabric F is vibrated, thereby facilitating the release of trapped water and residues. In some embodiments, the vibration generator 5 is configured to cause an amplitude of at least 10 μm, preferably at least 15 μm, and more preferably at least 20 μm. In some embodiments, the amplitude may be 50 μm or more. In both low-frequency and high-frequency embodiments, a larger amplitude is advantageous as it further increases the release of water and residues from the fabric F.

[0049] Figures 2a to 2b disclose a first embodiment of an apparatus 1 having a plurality of openings 3 arranged along a contact portion 2. The apparatus 1 is held by a holder 7 that also includes connection portions such as a transport connection portion 4” and a power supply. Providing the plurality of openings 3 is advantageous for performing uniform suction or blowing so that the entire width of the fabric F is cleaned or dehydrated. Also, providing the contact portion 2 across the entire width of the fabric F is advantageous in generating vibrations across the entire fabric F and releasing trapped water and residues. The preferred embodiment of Figures 2a to 2b is suitable for both uses when the air apparatus is a suction apparatus and when it is configured to supply pressurized air to the openings 3. The apparatus 1 also includes a housing 6.

[0050] Figures 3a to 3c disclose a second embodiment of an apparatus 1 having two contact portions 2a, 2b and a plurality of vibrators 5 that function as a vibration generator 5. In the second embodiment, the first row of vibrators 5a is arranged in a direction that is mechanically crosswise with respect to the first contact portion 2a, that is, in a direction perpendicular to the moving direction D of the fabric F, and the second row of vibrators 5b is arranged in a direction that is mechanically crosswise with respect to the second contact portion 2b. In this way, the vibrators 5a, 5b of each row are configured to vibrate one of the contact portions 2a, 2b. The apparatus 1 is connected to an air apparatus 4 (not shown) that supplies suction or pressurized air to the openings 3. In the embodiment of Figures 3a to 3c, air is transported to or from the openings 3 inside the housing 6 so that the inside of the housing 6 can be under negative pressure and suctioned into the apparatus 1 through the openings 3, or can be under high pressure and air can be blown out of the apparatus 1 through the openings 3.

[0051] The contact portions 2a, 2b preferably comprise sheet metal that can be easily vibrated by the vibrators 5.

[0052] By the vibration generator 5 being operatively connected to each of the contact portions 2a, 2b, they can vibrate independently of each other. This may be caused by separate vibrators for each of the contact portions 2a, 2b, as shown in FIGS. 3a to 3c, or alternatively, a single vibration generator 5 may be caused by being operatively connected to both of the contact portions 2a, 2b so that individual vibrations are possible. The vibration generator 5 may be in the form of a sonotrode or a plate-shaped ultrasonic vibrator (for example, a sonoplate).

[0053] In some embodiments, the contact portions 2a, 2b are configured to vibrate at different frequencies and / or different amplitudes in this way, but in other embodiments, instead, they may be configured to vibrate at the same frequency and / or amplitude.

[0054] In some embodiments, the contact portions 2a, 2b are instead connected to the vibration generator 5 so that they vibrate together.

[0055] In the third embodiment, the contact portion 2 is in the form of a cylinder of a part of the cylinder, and the first side surface A is on the outside of the cylinder. In this embodiment, at least one opening 3 is a plurality of openings 3 arranged in the contact portion so that air can be transported through the contact portion, that is, transported from the inside of the cylinder to the outside (blowing out) or from the outside of the cylinder to the inside (suction). The device 1 of this embodiment preferably forms a TAD (through air drying) cylinder configured to provide improved drying of the paper web by a combination of the vibration of the contact portion 2 and the air flow through the plurality of openings 3.

[0056] For all embodiments disclosed in this specification that disclose the air device 4 as a suction device, the device 1 may be alternatively modified to have the air device 4 as an air knife. Similarly, when an embodiment is described using an air knife, this can be changed to a suction device without substantially modifying the device 1 itself. In some embodiments, the air device 4 may also have a dual function and may be configured to switch between a suction function and a blowing function.

[0057] Next, with reference to FIGS. 4 and 5, the paper-making machines 100, 100' according to the present invention will be described. In particular, it should be noted that the present invention includes any type of paper-making machine as long as at least one device 1 according to the present invention is attached. However, since the cleaning and dewatering of the structured fabric used in a tissue paper-making machine are particularly difficult, the present invention is particularly advantageous in a paper-making machine for manufacturing tissue paper.

[0058] FIG. 4 discloses a paper-making machine 100 according to a first embodiment of the present invention in a through-air drying (TAD) design. The paper-making machine 100 includes at least one, preferably a plurality of devices 1 according to the present invention in any or all of the press section 20, the structuring section 30, and the cleaning section 60. In other embodiments, at least one device 1 may also be included in any of the other sections of the paper-making machine 100, where appropriate.

[0059] The paper machine 100 includes a forming section 10 in which a base paper containing diluted pulp is injected into a forming nip between a first fabric 71, which may be called a forming fabric, and a second fabric 72, which may be called an inner wire. Thereby, a paper web P is produced which is transported onto the second fabric 72 through a press section 20 for pressing and dewatering. Subsequently, the paper web P is transferred to a third fabric 73, which may be called a structured fabric, transported through a structuring section 30, and structured and dried on at least one, suitably two, dryer rolls 31, 32. Thereafter, the paper web P is transferred to a drying section 40, which suitably includes a Yankee dryer for removing residual moisture, and from there the finished paper is transferred to a roll section 50 for rolling. This operation of the through-air drying machine TAD is well known in the art.

[0060] The first, second, and third fabrics 71, 72, 73 each form an endless loop, are configured to move in the machine direction M when transporting the paper web P, and return in the opposite direction when the paper web P is transferred to a subsequent section. While returning, each fabric 71, 72, 73 is washed. For the third fabric 73, a washing section 60 is provided to enable complete washing and drying.

[0061] In the press section 20, at least one device 1 can be arranged to dewater the second fabric 72, and thus the paper web P, by combining the vibration of the contact portion 2 and the negative pressure from an air device 4 functioning as a suction device. This has the advantage of firmly attaching the paper web P to the second fabric 72 and efficiently dewatering the second fabric 72, and thus the paper web P.

[0062] In the structuring section 30, at least one device 1 can be arranged either before, between, or after the dryer rolls 31, 32 to dehydrate the third fabric 73. Similar to the use of the device 1 in the pressing section 20, the air device 4 is configured to function as a suction device by providing a negative pressure for dehydrating the third fabric 73. This combines efficient dehydration with improved adhesion to the third fabric 73 and has the same advantages as when used in the pressing section 20.

[0063] In the cleaning section 60, at least one device 1 can be arranged within a cleaning station (not shown), where the third fabric 73 is cleaned by supplying a cleaning liquid such as water and dried by dehydration.

[0064] In the prior art, cleaning is generally performed by spraying the cleaning liquid onto the fabric at high pressure and using at least one Uhle box or air knife to suck up the liquid from the fabric or blow the liquid off the fabric.

[0065] In the paper-making machine 100 of the present invention, at least one such Uhle box or air knife can be replaced with the device 1 according to the present invention. When cleaning the third fabric 73, it is advantageous to provide an air device 5 that functions as a suction device in the device 1 because the efficiency of removing the liquid is improved compared to a conventional Uhle box. However, it is also advantageous to provide an air device 5 configured to blow pressurized air onto the third fabric 73 in the device 1 because in this case, the liquid is efficiently removed and the paper web P is not conveyed while the third fabric 73 is in the cleaning section 60.

[0066] It is particularly advantageous to combine at least one device 1 that functions as a suction device for the cleaning section 60 with at least one device 1 that functions as an air knife and supplies pressurized air to the third fabric 73, since this results in both complete cleaning and drying of the third fabric 73. The device 1 of the present invention may be provided either before the third fabric 73 enters the cleaning station 61, inside the cleaning station 61, after the cleaning station 61, or any combination thereof.

[0067] In the forming section 10, at least one device 1 according to the present invention can be arranged to dewater or clean the first fabric 71 while the first fabric 71 returns to the forming nip FN. The device 1 may be configured as a suction device or a blowing device, and if one or more devices 1 are provided, they may be configured in the same way or in different ways.

[0068] The drying section 40 may also optionally comprise a device 1 according to the present invention arranged before drying in the Yankee dryer 41.

[0069] Among the many possible arrangements of the device 1 according to the present invention, it may be particularly advantageous to provide the device 1 in relation to the first roll downstream of the forming nip FN. It may also be particularly advantageous to provide the device 1 in relation to the roll that transfers the paper web to the third fabric 73 or downstream of these rolls and upstream of the TAD cylinder.

[0070] Figure 5 discloses a paper machine 100' according to a second embodiment of the present invention. This paper machine 100' is a DCT (dry crepe tissue) paper machine equipped with a crescent-shaped former suitable for the production of tissue paper, and the paper machine 100' in Figure 5 mainly differs from the paper machine 100 of the first embodiment in that it does not have a structuring section 30. Among the parts and components of the paper machine 100' of the second embodiment that are similar or identical to those of the paper machine 100 of the first embodiment, the same reference numerals are appended with a prime symbol "’".

[0071] Therefore, in the paper-making machine 100' of the second embodiment, in order to generate the paper web P', the base paper is injected into the forming nip FN', and the forming section 10 formed between the first fabric 71' (which can be called the forming fabric) and the second fabric 72' (which can be called the felt) is provided. In the press section 20', the paper web P' is conveyed onto the second fabric 72', pressed and dehydrated before reaching the drying section 40', and in the drying section 40', it is transferred to the Yankee dryer 41' to remove the remaining moisture before being transferred to the roll section 50' for rolling. Similar to the first embodiment, the first fabric 71' and the second fabric 72' are washed while they are returning, and in the case of the second fabric 72', a washing station 61' is provided in the washing section 60'.

[0072] The device 1 of the present invention may be provided in any of the forming section 10', the press section 20', and the washing section 60'. In the case where the drying section 40' has a configuration including components before the Yankee dryer 41', at least one device 1 may be arranged in the drying section 40'.

[0073] Regarding the first embodiment, the device 1 is preferably used to dehydrate the paper web P' conveyed by the second fabric 72', and the air device 5 is configured as a suction device to protect the paper web P' and improve the adhesion to the second fabric 72'.

[0074] When the device 1 is arranged in the cleaning station 60' in relation to the first fabric 71' or the second fabric 72', or when the second fabric 72' does not convey the paper web P', the air device 5 is preferably configured as either a suction device similar to the Uhle box or a blowing device similar to the air knife. The combination of vibration and suction is very advantageous in the cleaning and dewatering of the first fabric 71' or the second fabric 72', and the combination of vibration and the blowing of pressurized air is very advantageous in the cleaning and drying of the first fabric 71' or the second fabric 72'.

[0075] The device 1 of the present invention can be attached to the paper machines 100, 100' during the manufacture of the paper machines 100, 100', but it can also be used to retrofit an existing paper machine to form the paper machines 100, 100' of the present invention by adding at least one device 1 according to any embodiment of the present invention disclosed herein.

[0076] Note that the features from the various embodiments described herein can be freely combined as long as such a combination is not explicitly stated to be inappropriate.

Claims

1. An apparatus for dewatering or cleaning a fabric in a paper machine, comprising: a contact portion (2) arranged on a first side (A) of the apparatus (1) for contacting the fabric within the paper machine; an air device (4) for transporting air to or from the fabric, the air device (4) being operatively connected to at least one opening (3) in the first side (A) for supplying or removing air through the at least one opening (3); a vibrator (5) operatively connected to the contact portion (2) and configured to cause vibration of the contact portion (2) during operation of the apparatus (1). An apparatus comprising the above components.

2. The apparatus according to claim 1, wherein the at least one opening (3) is arranged at a downstream end (DS) of the first side (A), and the contact portion (2) is arranged at an upstream end (US) of the first side (A).

3. The apparatus according to claim 1, wherein the at least one opening (3) is arranged at an upstream end (US), and the contact portion (2) is arranged at a downstream end (DS) of the first side (A).

4. The apparatus according to claim 1, wherein the at least one opening (3) is arranged in the contact portion (2) such that air is supplied to or removed from the fabric through the contact portion (2).

5. The apparatus according to any one of claims 1 to 4, wherein the air device (4) is a suction device for sucking air from the fabric into the opening.

6. The apparatus according to any one of claims 1 to 4, wherein the air device is an air knife for blowing air from the opening onto the fabric.

7. The apparatus according to any one of claims 1 to 6, wherein the vibrator (5) is configured to operate at a frequency of at least 10 kHz, preferably at least 15 kHz, more preferably at least 20 kHz.

8. The apparatus according to any one of claims 1 to 7, wherein the vibrator (5) is configured to cause an amplitude of the contact portion of at least 10 μm, preferably at least 15 μm, more preferably at least 20 μm during operation of the apparatus.

9. The apparatus according to any one of claims 1 to 8, further comprising at least two contact portions (2a, 2b), wherein the vibration generator (5) is operatively connected to each of the contact portions (2a, 2b) and is configured to vibrate them independently of each other.

10. The contact portion (2) is a cylinder, preferably a TAD cylinder for a paper machine, and a plurality of openings (3) are arranged in the contact portion (2) to enable air transportation through the contact portion (2). The apparatus according to any one of claims 5 to 8 when dependent on claim 4 or claim 4.

11. A paper machine comprising at least one apparatus (1) according to any one of claims 1 to 10.

12. At least one apparatus (1) is arranged in the forming section (10, 10') of the paper machine (100, 100') and is configured to dewater a first fabric (71, 71') that conveys a paper web. The paper machine according to claim 11.

13. At least one apparatus (1) is arranged in the press section (20, 20') of the paper machine (100, 100') and is configured to dewater a second fabric (72, 72') that conveys a paper web. The paper machine according to claim 9 or 10.

14. At least one apparatus (1) is arranged in the structuring section (30) of the paper machine (100, 100') and is configured to dewater a third fabric (73) that conveys a paper web. The structuring section (30) is preferably a through-air drying section TAD. The paper machine according to any one of claims 11 to 13.

15. At least one apparatus (1) is arranged in the drying section (40, 40') of the paper machine (100, 100') and is configured to dewater a fabric that conveys a paper web. The paper machine according to any one of claims 11 to 14.

16. At least one apparatus (1) is arranged in a cleaning section (60, 60') for cleaning a fabric. The paper machine according to any one of claims 11 to 15.

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