Paper machine belt and paper machine employing same

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a paper machine belt and to a paper machine.

BACKGROUND OF THE INVENTION

[0002] A paper machine for the production of tissue paper is disclosed in U.S. Patent No. 5,393,384, see particularly Figure 6. The paper machine shown therein has a belt impermeable to water, which runs in a loop through an extended press nip formed by a shoe press roll and a counter roll. A press felt is conveyed directly to the press nip, where it is brought together with the impermeable belt and the paper web. The paper web is transferred from a forming fabric to the impermeable belt which is to carry the paper web on its under side up to the press nip and thence to the drying cylinder. The impermeable belt thus carries the paper web a relatively long distance after the paper web has been transferred from the forming fabric to the impermeable belt. There is therefore a risk of the paper web not adhering sufficiently strongly along the entire distance and thus becoming detached from the impermeable belt. According to the patent specification the adhesion force between the impermeable belt and the paper web is greater than that between the press felt and the paper web. The impermeable belt under discussion here is not compressible and has a smooth, web-carrying surface.

[0003] It is generally known that such a smooth, impermeable belt obtains a film of liquid on its smooth, web-carrying surface when belt, press felt and paper web pass together through a press nip and that, after the press nip, the paper web therefore adheres to the impermeable belt instead of to the press felt which does not have a smooth surface, when the press felt and the impermeable belt run away from each other. This situation is also utilized in U.S. Patent No. 4,483,745. Since, however, both the impermeable belt and the drying cylinder in the paper machine according to U.S. Patent No. 5,393,384 have smooth surfaces with which the paper web is intended to come into contact, there is considerable risk of the paper web continuing to adhere to the smooth surface of the impermeable belt after it has passed the nip at the drying cylinder instead of being transferred to the smooth surface of the drying cylinder as desired. Probably not even the application of large quantities of adhesive on the envelope surface of the drying cylinder would ensure adhesion of the paper web to the drying cylinder. U.S. Patent No. 5,393,384 mentions nothing about texturing the paper web before the drying cylinder.

[0004] DE-195 48 747 discloses a paper machine for manufacturing creped tissue paper which is provided with a press comprising a shoe press roll, a counter roll and a suction roll, the counter roll forming a first press nip with the suction roll and a second extended press nip with the shoe press roll. A felt passes through the two press nips together with the paper web and then carries the paper web with it to a Yankee dryer, to which the paper web is transferred when the felt and the paper web pass around a transfer roll forming a non-compressing nip with the Yankee dryer. Suction zones are provided before and after the first press nip, the suction zone before the press nip being situated within the suction roll whereas the suction zone after the press nip is in a side loop in which the felt runs alone and joins the paper web again at the entry to the second press nip. One drawback with such a paper machine is that the paper web is exposed to re-wetting by the wet felt before it reaches the Yankee dryer. The paper machine has no impermeable belt, nor does the patent specification mention anything about texturing the paper web.

[0005] U.S. Patent No. 5,298,124 discloses a compressible transfer belt for use in a paper or board making machine in order to eliminate open draws in the paper web and to easily release the paper web so that it can be transferred to a fabric or belt. The transfer belt carries the paper web through the press section, which comprises one or more press nips, and on to the drying section which comprises a plurality of drying cylinders and a belt passing in a loop around a transfer roll which forms a nip with the transfer belt. Each press is also provided with a felt passing through its press nip and enclosing the paper web between it and the transfer belt. The impermeable transfer belt is also so designed that a liquid film formed in a press nip between the transfer belt and the paper web breaks up when the pressure on the transfer belt ceases after the press nip so that its release properties increase and the paper web can thus more easily be transferred to a fabric or another belt running in a loop. There is no suggestion or intimation in the patent specification that the transfer belt should be allowed to carry the paper web to a drying cylinder in a tissue machine. Nor is there any mention of texturing the paper web.

[0006] U.S. Patent No. 5,298,124 offers an excellent description of the tasks a transfer belt cooperating with a press felt shall perform in a satisfactory manner, and also of the properties and design of such transfer belts which then were disclosed in patent specifications U.S. Patent Nos. 4,483,745, 4,976,821, 4,500,588, 5,002,638, 4,529,643 and CA-A-1,188,556. According to U.S. Patent No. 5,298,124, for a transfer belt intended for cooperation with a press felt the critical tasks are a) to remove the paper web from the press felt without causing instability problems; b) to cooperate with the press felt in one or more press nips to ensure optimal dewatering and high quality of the paper web, and c) to transfer the paper web in a closed draw from a press in the press section to a paper web receiving fabric or belt in the following press or presses of the press section or to a pick-up fabric in the drying section.

[0007] As mentioned, the transfer belt for the press section of a paper machine disclosed in U.S. Patent No. 5,298,124 has a web-contacting surface which is substantially impermeable to water and air and has a pressure-responsive microscale topography. Under influence of the pressure in a press nip in the press section, the transfer belt is compressed so that the microscale roughness of said surface is decreased, whereupon the surface becomes much smoother and allows the formation of a thin, continuous film of water thereon.

[0008] Paper machines for manufacturing soft paper with high bulk are known through a plurality of patent specifications. An imprinting fabric or felt is generally used which passes, together with the paper web formed, through a press nip in which the paper web is pressed into the imprinting fabric, thus acquiring a texture pattern on one side. Paper machines having such texturing fabrics and press nips are disclosed in U.S. Patent Nos. 3,301,746, 3,537,954, 4,309,246, 4,533,437, 5,569,358, 5,591,305 and WO 91/16493. The drawback with the paper machines disclosed in these publications is that dewatering in the press nip is relatively low and the dry solids content of the paper web is therefore low when the paper is transferred to the drying cylinder. The production rate of the paper machine is thus relatively low.

[0009] U.S. Patent No. 4,849,054 discloses a machine for manufacturing an imprinted fabric web with high bulk without the use of a press nip. A roll, e.g., a transfer roll or felt-carrying roll, forms a nip with an imprinting fabric at a transfer point for the web where the imprinting fabric passes around a suction tube with a slit opening facing the transfer point. The nip is so wide that the web is not compressed when it passes through. The suction effect from the suction tube via the narrow slit opening is sufficient to ensure that the web is not only transferred to the imprinting belt but is also shaped in compliance with the surface of the imprinting belt facing the web, this belt having a three-dimensional pattern. Prior to the transfer point the speed of the fabric web is greater than that of the imprinting fabric. The roll carrying the web to the non-compressing nip has a smooth surface and it is generally known that in practice considerable problems are entailed in transferring a fabric web from a smooth surface to a fabric, which fabric web has been pre-pressed to a dry solids content of 30-50%.

[0010] U.S. Patent No. 5,411,636 discloses manufacture of soft paper where the paper web is formed on a forming fabric, pre-pressed in a double-felted press nip and transferred to a coarse-meshed fabric. When the paper web is carried by the coarse-meshed fabric it is subjected to a vacuum in a suction zone so that the paper web is sucked into the openings and depressions in the fabric and thereby acquires increased thickness and thus increased bulk. The coarse-meshed fabric then carries the paper web to the drying cylinder. The double-felted press nip ensures that the dry solids content of the paper web is relatively low, i.e., 25-30%. Since no dewatering can be performed in the nip at the drying cylinder, the dry solids content of the paper web upon transfer to the drying cylinder is correspondingly low. Furthermore, it is extremely difficult to transfer the paper web from the felt to the coarse-meshed fabric.

[0011] Document WO 96/00812 describes a web supporting apparatus in the form of a drying belt or press fabric for making a paper web, comprising a dewatering felt layer having a surface facing the web, and a web patterning layer of a photosensitive resin defining a web contacting top surface. The web patterning layer has either a plurality of discrete openings surrounded by projections or a plurality of discrete projections surrounded by spaces, said openings and spaces, respectively exposing the felt layer to the web so that the felt is cabable of receiving and containing water from the wet web.

[0012] Accordingly, an improved paper machine and method of manufacturing textured soft paper would enable the manufacture of a textured fibrous web with high bulk and high dry solids content before the drying cylinder to enable a high production rate to be achieved at a reasonable cost. Further, it would be desirable to reliably transfer the textured fibrous web to the drying cylinder although the fibrous web is carried to the drying cylinder by an impermeable texturing belt.

SUMMARY OF THE INVENTION

[0013] The invention refers to a paper machine belt for advancing a wet fibrous paper web between a press and a heated drying cylinder of a paper machine, wherein the belt is a substantially impermeable belt which has a web-contacting surface and is adapted to pass with the fibrous web through the press and then carry the fibrous web to the drying cylinder, whereby said web-contacting surface defines a multitude of regularly distributed depressions and surface portions located between said depressions, so that the belt is a texturing belt, forming on the fibrous web an equivalent textured pattern, and that the texturing belt or a layer of the texturing belt intended for contact with the paper web is reversibly compressible so that the texturing belt is compressed in a transfer nip at the drying cylinder and resumes its uncompressed state when leaving said transfer nip.

[0014] The invention also refers to a paper machine for treating a wet fibrous paper web, comprising:

• the paper machine belt according to any one of claims 1 to 13,
• a press section comprising a first press having a press roll and a counter roll to form an extended press nip therebetween for pressing the fibrous web and removing water from the fibrous web, characterized in that when the belt passes with the fibrous web through the press, said depressions and said surface portions initially form on the fibrous web an equivalent textured pattern having thicker and thinner portions, and when the belt carries the fibrous web to the drying cylinder, said surface portions engage the thinner portions of the fibrous web against the surface of the drying cylinder and water in the thicker portions of the fibrous web is caused to evaporate.

[0015] According to the invention it has surprisingly been found that impermeability or substantial impermeability is an extremely favourable property in a texturing belt, that is included in the paper machine according to the invention if the impermeable texturing belt is also used to transport a pressed paper web to the transfer nip at a Yankee dryer in the drying section of the paper machine. The property allows steam which, as a result of heating the Yankee dryer is formed in the depressions or pits in the texturing pattern by the water present in the pits or depressions, to be pressurized, thus pressing the paper fibers also present in the pits or depressions as a result of the press effect in the press section, so that these in the Yankee dryer nip are pressed into the pits or depressions at the same time as the parts of the paper fiber web present between the raised parts of the texturing pattern and the Yankee dryer become thinner. The desired texturing effect and high bulk of the paper web is thus achieved.

[0016] The texturing effect and the productivity can be increased if the texturing belt or a layer of the texturing belt intended for contact with the paper web is also given the feature of reversible compressibility so that the texturing belt is compressed in the transfer nip at the Yankee dryer. When the texturing belt then leaves the transfer nip and resumes its uncompressed state, a vacuum is created, which contributes to the formation of steam, which in turn facilitates separation of the texturing belt and paper web after the transfer nip and also quicker drying of the paper web on the Yankee dryer, i.e., higher paper production capacity. The vacuum-forming effect increases the quicker the belt resumes its uncompressed state, i.e., the more resilient the reversible compressibility is.

[0017] The texturing effect of the texturing belt that is included in the paper machine according to the invention is, of course, selected taking into consideration the desired texture pattern in the paper to be manufactured. The texture pattern is regular across the texturing belt or, if the texture pattern in the paper web is to include a particularly prominent additional pattern, e.g., a picture, logotype, etc., it has a regular basic pattern of depressions or pits and raised portions, onto which pattern the additional pattern is superimposed. "Regular" does not necessarily imply that the pattern appears regularly in all directions of the texturing belt. For instance, if the paper is soft paper that is to be creped, a tighter dominant transverse pattern (across the machine direction) as compared with a longitudinal pattern of elevations and pits, will give an increased creping effect. Thus, the pattern can be used for altering the properties of the paper in a desired direction.

[0018] Taking into consideration the material in the texturing belt or its surface layer that is intended to come into contact with the paper web, the texturing pattern can be achieved in some manner, known per se, such as etching, calendering, laser processing or embossing.

[0019] The density of the texturing pattern can also be used to influence the effect of the drying of the paper web on the Yankee dryer. Fewer contact points between the Yankee dryer and the paper web thus results in reduced drying effect from the Yankee dryer but increased drying effect from the hot air hood around the Yankee dryer on the fluffier parts of the paper web located between the thinner contact points.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention will be described in more detail in the following with reference to the attached drawings.

Figure 1 shows a paper machine according to a first embodiment of the invention.

Figure 2 shows a paper machine according to a second embodiment of the invention.

Figure 3 shows a paper machine according to a third embodiment of the invention.

Figure 4 shows a paper machine according to a fourth embodiment of the invention.

Figure 5 shows a paper machine according to a fifth embodiment of the invention.

Figure 6 shows in perspective a part of a substantially impermeable texturing belt constructed of a back layer in the form of a tight polymer layer and a web-contacting layer in the form of a polymer-coated fabric.

Figure 7 shows from above a part of a substantially impermeable texturing belt constructed of a back layer in the form of a carrier and a web-contacting layer supported by the carrier, in the form of a resilient, compressible polymer layer, which polymer layer is provided with longitudinal grooves.

Figure 8 shows a section through the texturing belt according to Figure 7.

Figure 9 shows from above a part of a substantially impermeable texturing belt of the same type as that according to Figure 7, but provided with diagonally intersecting grooves.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

[0022] Figures 1-3 show schematically parts of paper machines for manufacturing a textured web 1 of soft paper, such as tissue and other paper products with low density. Each of the paper machines comprises a wet section 2, a press section 3 and a drying section 4.

[0023] The wet section 2 includes a headbox 7 a forming roll 8, an endless, carrying, inner clothing 9 and an endless, covering outer clothing 10 consisting of a forming fabric. The inner and outer clothings 9, 10 run, each in its own loop, around a plurality of guide rolls 11 and 12, respectively.

[0024] The drying section 4 includes a drying cylinder 5 covered by a hood 30. The drying cylinder is suitably a Yankee dryer. At the outlet side of the drying section a creping doctor is arranged to crepe the fibrous web 1 off the Yankee dryer. An application device 31 is also provided for applying a suitable adhesive on the envelope surface of the Yankee dryer 5 immediately before the transfer nip.

[0025] The press section 3 includes a shoe press with a shoe press roll 14 and a counter roll 19, these rolls 14 and 19 forming an extended press nip with each other. The press section also has an endless press felt 15 which runs in a loop around guide rolls 6, and an endless, substantially impermeable belt 16, which according to the invention is a texturing belt. The substantially impermeable texturing belt 16 runs in a loop around the counter roll 19, a transfer roll 17 and a plurality of guide rolls 18. The transfer roll 17 forms a transfer nip with the Yankee dryer 5 with low linear load, i.e., about 30 to 60 kN (kiloNewtons), through which transfer nip the substantially impermeable texturing belt 16 thus passes.

[0026] In the embodiments shown in Figures 1 and 2 the press section 3 also includes a roll press, constituted by a suction press roll 13 and said counter roll 19 to form a press nip, through which the substantially impermeable texturing belt 16 and the press felt 15 pass together with the fibrous web 1. After this initial press nip, the press felt 15 is conducted away from the fibrous web 1 and the substantially impermeable texturing belt 16 in a side loop around the suction press roll 13 and two guide rolls 32. The press felt 15 rejoins the fibrous web and the substantially impermeable texturing belt 16 immediately before the extended press nip. If desired, suction devices may be arranged within this side loop of the press felt 15 in order to increase the capacity of the press felt to absorb water at the entrance to the extended press nip.

[0027] In the embodiments shown in Figures 1 and 3, the inner clothing 9 of the wet section 2 is a felt guided to the press section 3 to be also utilized as press felt 15, and which thus runs in a loop back to the forming roll 8.

[0028] In the embodiment shown in Figure 2, the inner clothing 9 of the wet section 2 is a forming fabric, the press felt running around a pick-up roll 20 arranged close to the loop of fabric 9, so that press felt 15 and fabric 9 run in contact with each other to transfer the fibrous web from the fabric 9 to the press felt 15. The pick-up roll 20 may be provided with a suction shoe (not shown). Alternatively, the pick-up roll with suction shoe may be replaced by a pick-up suction box.

[0029] Figure 4 shows schematically parts of a paper machine according to another embodiment of the invention. It is similar to that shown in Figure 1 with the exception that the press felt 15 is not led in a side loop between the two press nips, but instead accompanies the counter roll 19, so that the fibrous web 1 is held enclosed between the substantially impermeable texturing belt 16 and the press felt 15. This embodiment can be used when there is little risk of rewetting of the fibrous web.

[0030] Figure 5 shows schematically parts of a paper machine according to yet another embodiment of the invention for manufacturing a textured web of soft paper, such as tissue and other sanitary paper products. The paper machine comprises a wet section 2, a press section 3 and a drying section 4. The wet section 2 includes a headbox 7, a forming roll 8, an endless, carrying inner clothing 9 and an endless, covering, outer clothing 10 constituted by a forming fabric. The inner and outer clothings 9 and 10 run in individual loops around a plurality of guide rolls 11 and 12, respectively. The drying section 4 includes a drying cylinder 5 covered by a hood 30. The drying cylinder is suitably a Yankee dryer. At the outlet side of the drying section a creping doctor 21 is provided to crepe the fibrous web off the Yankee dryer 5. An application device 31 is also provided for applying a suitable adhesive on the envelope surface of the Yankee dryer 5 immediately before the transfer nip. The press section 3 includes a shoe press with a shoe press roll 14 and a counter roll 19, these rolls 14 and 19 forming an extended press nip with each other. The press section also has an endless press felt 15 which runs in a loop around guide rolls 6, and an endless, substantially impermeable belt 16, which according to the invention is a texturing belt. The substantially impermeable texturing belt 16 runs in a loop around the counter roll 19, a transfer roll 17 and a plurality of guide rolls 18. The transfer roll 17 forms a transfer nip with the Yankee dryer 5 with low linear load, through which transfer nip the substantially impermeable texturing belt 16 thus passes. In this embodiment the substantially impermeable texturing belt 16 is also used as the inner clothing 9 in the wet section 2, its loop being extended to the forming roll 8. The substantially impermeable texturing belt 16 thus runs in a loop between the wet section 2 and the drying section, around the transfer roll 17, guide rolls 18 and 11 and forming roll 8. The substantially impermeable texturing belt carries the fibrous web on its under side from the forming roll to the drying cylinder.

[0031] In the embodiments shown in Figures 1 to 5, the counter roll 19 is a smooth roll and is arranged in a loop of the substantially impermeable texturing belt 16. In an alternative embodiment (not shown) of the press section according to Figures 3 and 5, the positions of the rolls 14 and 19 are reversed, i.e., the shoe press roll 14 is arranged in the loop of the substantially impermeable texturing belt 16, and the counter roll is in the loop of the press felt 15. In such a configuration the counter roll may be a suction roll, a grooved roll or a blind-drilled roll.

[0032] The substantially impermeable texturing belt used in the embodiments above of the paper machine according to the invention comprises a back layer 33 and a web-contacting layer 34 having a multitude of uniformly distributed depressions 35 with flat or arched surface portions 36 situated therebetween, see Figures 6 to 9. According to the first embodiment, shown in Figure 6, the substantially impermeable texturing belt 16 consists of a tight layer 33 forming said back layer and a fabric forming said web-contacting layer 34. The fabric 34 is coated with a polymer enclosing the threads of the fabric without altering the structure of the fabric, which is formed of depressions and arched or convex surface portions 36 situated between the depressions. The depressions 35 and surface portions 36 are in turn formed by the threads of the fabric extending in the machine direction (as indicated by the arrow) and transverse to this. The depressions 35 are sealed by the tight back layer 33 formed by coating polymer on the surface of the fabric not coming in contact with the web. Said arched surface portions 36 comprise both oblong arc-shaped ridges 36a of the longitudinally running fabric threads, and also knuckles 36b of the transversely running threads, which knuckles produce small bowl-shaped pits in the fibrous web in the texturing phase. In the embodiment shown in Figure 6, the substantially impermeable texturing belt has 100 knuckles 36b per cm². In general it may have 25 to 150 knuckles/cm², preferably 50 to 100 knuckles/cm². This structure of depressions, ridges and knuckles produces a corresponding texture pattern in the fibrous web when it runs through the extended press nip together with the texturing belt 16 and press felt 15. The polymer coating on the fabric ensures that the fibrous web is reliably adhered to the substantially impermeable texturing belt as it runs out from the extended press nip. This ensures that the fibrous web accompanies the substantially impermeable texturing belt 16 and not the press felt 15. The structure of the web-contacting layer of the impermeable texturing belt, i.e., the polymer-coated fabric 34, combined with the envelope surface of the drying cylinder 5 being coated with a continuous adhesive layer, also ensures that the fibrous web is safely transferred to the drying cylinder 5 when it passes through and out of the transfer nip.

[0033] What is generally termed a coarse, single-layered fabric, having 100 knuckles/cm² may be used in the first embodiment of the substantially impermeable texturing belt described above. The back layer, which is substantially impermeable, may consist of a suitable polymer resin material, e.g., the polymers described below for the polymer layer in the second embodiment of the substantially impermeable texturing belt. The polymer for coating the fabric threads may be selected in the same way.

[0034] According to a second embodiment, the substantially impermeable texturing belt 16 consists of a carrier 33, which forms said back layer 33, and a polymer layer 34 on its web-contacting side having a hardness of 50 to 97 Shore A, the polymer coating having a degree of roughness in uncompressed state of R_z = 2 to 80 µm, measured in accordance with ISO 4287, Part I, and being compressible to a lower degree of roughness of R_z = 0 to 20 µm when a linear load of 20 to 200 kN/m is applied in the substantially impermeable texturing belt, and also has the ability to be recovered to its uncompressed degree of roughness when the pressure exerted on the substantially impermeable texturing belt ceases. The R_z-value is more specifically the ten-point height, which is defined in said ISO norm as the average distance between the five highest peaks and the five deepest valleys in the reference length measured from a line parallel to the mid-line and not crossing the surface profile. The substantially impermeable texturing belt preferably has an air permeability of less than 6 m³/m²/minute, measured in accordance with the procedure described in "Standard Test Method for Air Permeability of Textile Fabrics, ASTM D 737-75, American Society of Testing and Materials".

[0035] The substantially impermeable texturing belt 16 is thus compressible under the influence of the pressure forces prevailing in the extended press nip. The substantially impermeable texturing belt 16 therefore assumes an uncompressed state upstream and downstream of the extended press nip, the surface, the web-carrying surface facing the fibrous web, having a high degree of roughness in the uncompressed state of the substantially impermeable texturing belt and a lower degree of roughness in the compressed state of the substantially impermeable texturing belt, so that the web-carrying surface in the compressed state of the substantially impermeable texturing belt is sufficiently smooth for a continuous liquid film to be formed on the web-carrying surface, when the substantially impermeable texturing belt, together with press felt 15 and fibrous web 1, passes through the extended press nip, and so that the web-carrying surface in the uncompressed state of the substantially impermeable texturing belt is sufficiently rough to permit the continuous liquid film to be broken up after the substantially impermeable texturing belt has expanded in thickness.

[0036] The compressible polymer layer 34 is provided with said multitude of uniformly distributed depressions 35, in order to take up a large share of the web-contacting surface, viz. from 20% up to 50%. The depressions can be formed in many ways to achieve the desired effect of texturing a relief pattern in the fibrous web in order to increase its bulk. The depressions may consist of continuous grooves in the polymer layer 33, see Figure 7, which extend in machine direction. According to another embodiment, the grooves extend diagonally from one edge to the other, forming an angle of 10° to 80° to the machine direction. According to another embodiment, see Figure 8, the depressions consist of diagonally intersecting grooves which extend in one group from the first edge to the second edge, and in a second group from the second edge to the first edge, intersecting grooves forming an angle α of 10° to 170°. The grooves in the various embodiments may be straight, as shown, or wave shaped or the like, e.g., sinus shaped or zigzag shaped. The distance a between two grooves 35 running in the same direction may be within the interval 1 to 3 mm. The width b of the groove is within the interval 0.5 to 1.0 mm and its depth c within the interval 0.1 to 1.0 mm.

[0037] According to another embodiment (not shown) the depressions comprise hollows of the same or similar shapes. These hollows may be circular, elliptical or polygon in shape, e.g., triangular, rectangular or hexagonal, the largest dimension lying within the interval 0.5 to 3.0 mm and the depth within the interval 0.5 to 1.0 mm.

[0038] All or some of the depressions, individually or in groups, may be constituted by hollows of special symbol shapes, e.g., numbers, letters, trade or company symbols repeated at regular intervals within a length unit of the belt.

[0039] The substantially impermeable texturing belt according to said second embodiment may be built up in accordance with the recipes described in U.S. Patent No. 5,298,124, discussed in the introduction. The polymer coating 34 comprises a polymer composition such as acrylic polymer resin, polyurethane polymer resin and polyurethane/polycarbonate resin composition. The polymer coating also contains particles of a filler, which have a different hardness from the polymer material and may consist of kaolin, clay, polymer material or metal, preferably stainless steel. The carrier constituting the back layer 33 includes all types of base elements that can in some way be made endless. The term also covers base elements provided with seams. The carrier may consist, for instance, of a single-layered or multi-layered fabric produced from monofilaments such as polyester, polyamide, and the like. The base element may even consist of a fiber web (non-woven) held together by adhesive, combined wound yarns, polymer foil/film, warp knitting, or the like. The carrier may be coated on the rear side with a polymer material of the same type as that used for the polymer layer 34.

[0040] It is surprising that a transfer belt as described in U.S. Patent No. 5,298,124, which is intended for pressing in a press section and usable for transferring a paper web from the press section to a drying fabric, can be used with great advantage for texturing and transferring a soft paper web from a shoe press nip directly to a Yankee dryer or some other drying cylinder. As is well known, the conditions at a Yankee dryer are completely different from those in a conventional press nip. With a Yankee dryer, no pressing of the soft paper occurs for direct dewatering. Rather it is a question of supporting the soft paper web to the envelope surface of the Yankee dryer, so that the fibers of the soft paper web adhere efficiently to the surface of the Yankee dryer, thereby achieving good heat transfer to the paper web. This is exactly the effect which is achieved with the transfer belt included in one embodiment of the paper machine according to the present invention, but cannot be achieved with a press felt as described in DE-195 48 747 due to the paper being exposed to rewetting after the last press nip in the press section, which prevents satisfactory adhesion. Neither can it be achieved, or only to a minor extent, with a transfer belt as described in U.S. Patent No. 5,393,384 for the reason stated above. The compressibility of the transfer belt used in the paper machine according to the invention results in lower specific pressure at the adhesion point, which in turn offers increased rate of operation, i.e., higher production rate. This property also results in increased vaporization of water from the soft paper web, i.e., quicker drying of the soft paper web on the Yankee dryer, which also contributes to higher production rates.

[0041] The paper machine according to the invention, the press nips of which being single-felted, produces a textured fibrous web with a high dry solids content before the drying section, viz. up to 55%, which should be compared with the dry solids contents of up to 45% achieved with paper machines in practical use today. This improvement can be utilized either to run the paper machine at a higher production rate or to reduce the energy consumption in the drying section. It is also then possible to reduce the diameter of the drying cylinder.

[0042] With the embodiments shown and described, a guide roll may be arranged, if desired, in the loop of the substantially impermeable texturing belt 16 immediately before the transfer roll 17.

[0043] With the embodiments shown and described, a transfer member is used constituted by the transfer roll 17. According to an alternative embodiment (not shown), the transfer roll is replaced by the substantially impermeable texturing belt itself, which is allowed to run around a predetermined part of the drying cylinder, e.g., within a sector angle of 30° to 60°, to form an extended transfer nip with the drying cylinder.

[0044] Although the embodiments of the paper machine described above all have press sections comprising a shoe press, the invention is also applicable when the press section lacks a shoe press and instead has at least one press with two press rolls, of which the press roll around which the press felt runs is a suction roll, a grooved roll or a blind-drilled roll.

Claims

1. A paper machine belt for advancing a wet fibrous paper web (1) between a press (14, 19) and a heated drying cylinder (5) of a paper machine, wherein the belt (16) has a web-contacting surface and is adapted to pass with the fibrous web (1) through the press (14, 19) and then carry the fibrous web (1) to the drying cylinder (5), said web-contacting surface defining a multitude of regularly distributed depressions (35) and surface portions (36) located between said depressions (35), so that the belt (16) is a texturing belt, forming on the fibrous web (1) an equivalent textured pattern, said texturing belt (16) or a layer (34) of the texturing belt (16) intended for contact with the paper web (1) being reversibly compressible so that the texturing belt (16) is compressed in a transfer nip at the drying cylinder (5) and resumes its uncompressed state when leaving said transfer nip, characterized in that said belt (16) is substantially impermeable, wherein the air permeability of the belt (16) is less than 6m³ /m² x min, measured in accordance with the procedure described in "Standard Test Method for Air Permeability of Textile Fabrics, ASTM D737-75, American Society of Testing and Materials"

2. The belt according to claim 1, wherein a vacuum is created in the depressions (35) when the texturing belt (16) leaves the transfer nip and resumes it uncompressed state.

3. The belt according to claim 2, wherein said vacuum contributes to the formation of steam in the depressions in the texturing pattern, which steam in turn facilitates separation of the texturing belt (6) and paper web (1) after the transfer nip and also quicker drying of the paper web on the drying cylinder (5).

4. The belt according to any one of claims 2 and 3, wherein the vacuum-forming effect is controlled by the resiliency of the texturing belt (16) in that the vacuum-forming effect increases the more resilient the reverse compressibility is.

5. The belt according to any one of claims 1 to 4, wherein the belt has a texture pattern that is regular.

6. The belt according to claim 5, wherein the texture pattern includes a particularly prominent additional pattern.

7. The belt according to claim 6, wherein the particularly prominent additional pattern is selected from the group consisting of pictures, logotypes numbers, trade symbols, and company symbols.

8. The belt according to any one of claims 1 to 7, comprising a back layer (33) and a layer (34) having said web-contacting surface comprising resilient compressible polymer layer having a hardness in the range from 50 to 97 Shore A, and defining said web-contacting surface.

9. The belt according to claim 8, wherein said web-contacting surface has a pressure responsive, recoverable degree of roughness in an unloaded state of R_z = 2 to 80 µm, measured in accordance with ISO 4287, Part I, and a lower degree of roughness of R_z = 0 to 20 µm when said polymer layer is compressed by a linear load of 20 to 200 kN/m as measured in a nonextended press nip.

10. The belt according to any one of claims 1 to 9, wherein said depressions (35) take up from 20% to 50% of said web-contacting surface.

11. The belt according to any one of claims 1 to 10, wherein said depressions are hollows of the same or similar geometric shapes including circular, elliptical or polygon shape, the largest dimension of each lying within the interval from 0.5 to 3 mm and depth within the interval 0.5 to 1 mm.

12. The belt according to any one of claims 1 to 10, wherein at least some of said depressions are hollows of non-geometric symbols shapes including numbers, letters, trade or company symbols with depths within the interval 0.5 to 1 mm.

13. A paper machine for treating a wet fibrous paper web (1), comprising: the paper machine belt (16) according to any one of claims 1 to 12; a press section (3) comprising a first press having a press roll (14) and a counter roll (19) to form an extended press nip therebetween for pressing the fibrous web (1) and removing water from the fibrous web (1); a heated drying cylinder (5) located downstream of said first press for receiving the pressed fibrous web (1) about a portion of the surface of said drying cylinder (5) and thereby further drying the fibrous web (1) by evaporating at least part of the water remaining in the fibrous web (1), wherein said belt (16) is arranged to carry the fibrous web (1) from said first press to said drying cylinder (5) such that said belt (16) engages the fibrous web (1) against the surface of said drying cylinder (5), characterized in that when the belt (16) passes with the fibrous web (1) through the press (14, 10), said depressions (35) and said surface portions (36) initially form on the fibrous web (1) an equivalent textured pattern having thicker and thinner portions, and when the belt (16) carries the fibrous web to the drying cylinder (5), said surface portions (36) engage the thinner portions of the fibrous web (1) against the surface of the drying cylinder (5) and water in the thicker portions of the fibrous web (1) is caused to evaporate.

14. The paper machine according to claim 13, further comprising a second press arranged upstream of said first press, said second press having two press members comprising a suction press roll (13) and a counter roll (19) to form a press nip, wherein said belt (16) is arranged to pass with the fibrous web (1) through said second press and said first press, and a press felt (15) arranged to run through said second press and first press against the fibrous web (1) for receiving water pressed from the fibrous web (1), and wherein said press felt (15) is arranged to be conducted away from the fibrous web (1) and the belt (16) in a side loop around said suction press roll (13) and guide rolls (32, 6).

15. The paper machine according to claim 14, wherein said press felt (15) is arranged to rejoin the fibrous web (1) and said belt (16) before the extended press nip.

16. The paper machine according to any one of claims 14 and 15, wherein suction devices are arranged within said side loop of the press felt (15) in order to increase the capacity of the press felt (15) to absorb water at the entrance to said extended press nip.

17. The paper machine according to any one of claims 13 to 16, further comprising a wet section (2) having an inner forming fabric (9), said press felt (15) running around a pick-up roll (20) arranged close to the loop of said fabric (9) and provided with a suction shoe.

18. The paper machine according to any one of claims 13 to 16, further comprising a wet section (2) having an inner forming fabric (9), said press felt (15), running around a pick-up suction box arranged close to the loop of said fabric (9).

19. The paper machine according to any one of claims 13 to 18, further comprising a transfer roll (17) arranged to engage said belt (16) and a fibrous web (1) against the surface of said drying cylinder (5).

Ansprüche

1. Papiermaschinenriemen zum Vorwärtsbewegen einer feuchten Faserpapierbahn (1) zwischen einer Presse (14, 19) und einem erwärmten Trocknungszylinder (5) einer Papiermaschine, wobei der Riemen (16) eine Bahnkontaktfläche hat und daran angepasst ist, mit der Faserbahn (1) durch die Presse (14, 19) zu treten und dann die Faserbahn (1) zu dem Trocknungszylinder (5) zu tragen, wobei die Bahnkontaktfläche eine Vielzahl an regelmäßig verteilten Vertiefungen (35) und Oberflächenabschnitten (36) definiert, die zwischen den Vertiefungen (35) angeordnet sind, so dass der Riemen (16) ein Texturriemen ist, der auf der Faserbahn (1) ein äquivalentes Texturmuster ausbildet, wobei der Texturriemen (16) oder eine Lage (34) des Texturriemens (16), die für einen Kontakt mit der Papierbahn (1) gedacht ist, reversibel komprimierbar ist, so dass der Texturriemen (16) in einem Übertragungsspalt an dem Trocknungszylinder (5) zusammengedrückt wird und seinen nicht zusammengedrückten Zustand wieder einnimmt, wenn er den Übertragungsspalt verlässt, dadurch gekennzeichnet, dass der Riemen (16) im Wesentlichen undurchlässig ist, wobei die Luftdurchlässigkeit des Riemens (16) geringer als 6 m³/m² x Minute ist gemessen gemäß der Prozedur, die in "Standard Test Method for Air Permeability of Textile Fabrics, ASTM D 737-75, American Society of Testing and Materials" beschrieben ist.

2. Riemen gemäß Anspruch 1, wobei ein Unterdruck in den Vertiefungen (35) erzeugt wird, wenn der Texturriemen (16) den Übertragungsspalt verlässt und seinen nicht zusammengedrückten Zustand wieder einnimmt.

3. Riemen gemäß Anspruch 2, wobei der Unterdruck zu dem Ausbilden von Dampf in den Vertiefungen in dem Texturmuster beiträgt, wobei der Dampf wiederum das Trennen des Texturriemens (6) und der Papierbahn (1) nach dem Übertragungsspalt erleichtert und außerdem ein schnelleres Trocknen der Papierbahn an dem Trocknungszylinder (5) erleichtert.

4. Riemen gemäß einem der Ansprüche 2 oder 3, wobei der Unterdruckausbildungseffekt durch die Elastizität des Texturriemens (16) dahingehend gesteuert wird, dass der Unterdruckausbildungseffekt zunimmt, je elastischer die Umkehrzusammendrückbarkeit ist.

5. Riemen gemäß einem der Ansprüche 1 bis 4, wobei der Riemen ein Texturmuster hat, das regelmäßig ist.

6. Riemen gemäß Anspruch 5, wobei das Texturmuster ein besonders vorragendes zusätzliches Muster aufweist.

7. Riemen gemäß Anspruch 6, wobei das besonders vorragende zusätzliche Muster aus der Gruppe gewählt wird, die aus Bildern, Firmenlogos, Zahlen, Warenkennzeichen und Firmenkennzeichen besteht.

8. Riemen gemäß einem der Ansprüche 1 bis 7, der eine Rückenlage (33) und eine Lage (34) aufweist mit der Bahnkontaktfläche, die eine elastische zusammendrückbare Polymerlage aufweist mit einer Härte in einem Bereich von 50 bis 97 Shore A und die die Bahnkontaktfläche definiert.

9. Riemen gemäß Anspruch 8, wobei die Bahnkontaktfläche einen auf Druck ansprechenden erzielbaren Rauhigkeitsgrad in einem unbelasteten Zustand von R_z = 2 bis 80 µm hat gemessen gemäß ISO 4287, Abschnitt I, und einen niedrigeren Rauhigkeitsgrad von R_z = 0 bis 20 µm hat, wenn die Polymerlage durch eine lineare Last von 20 bis 200 kN/m gemessen in einem Nichtlangpressspalt zusammengedrückt wird.

10. Riemen gemäß einem der Ansprüche 1 bis 9, wobei die Vertiefungen (35) von 20% bis 50% der Bahnkontaktfläche einnehmen.

11. Riemen gemäß einem der Ansprüche 1 bis 10, wobei die Vertiefungen Hohlräume mit gleichen oder ähnlichen geometrischen Formen sind, die eine kreisartige, elliptische oder polygonartige Form umfassen, wobei das größte Maß von jedem innerhalb des Intervalls von 0,5 bis 3 mm und eine Tiefe innerhalb des Intervalls von 0,5 bis 1 mm liegt.

12. Riemen gemäß einem der Ansprüche 1 bis 10, wobei zumindest einige der Vertiefungen Hohlräume aus Formen nicht geometrische Symbole sind inklusive Zahlen, Buchstaben, Warenkennzeichen oder Firmenkennzeichen mit Tiefen innerhalb des Intervalls von 0,5 bis 1 mm.

13. Papiermaschine zum Behandeln einer feuchten Faserpapierbahn (1) mit: dem Papiermaschinenriemen (16) gemäß einem der Ansprüche 1 bis 12; einer Pressenpartie (3) mit einer ersten Presse mit einer Presswalze (14) und einer Gegenwalze (19) zum Ausbilden eines Langpressenspalts zwischen ihnen zum Pressen der Faserbahn (1) und zum Entfernen von Wasser aus der Faserbahn (1); einem erwärmten Trocknungszylinder (5), der stromabwärtig der ersten Presse angeordnet ist zum Empfangen der gepressten Faserbahn (1) um einem Abschnitt der Fläche des Trocknungszylinders (5) herum und einem dadurch erfolgenden weiteren Trocknen der Faserbahn (1) durch ein Verdampfen von zumindest einem Teil des Wassers, der in der Faserbahn (1) verbleibt, wobei der Riemen (16) so angeordnet ist, dass er die Faserbahn (1) von der ersten Presse zu dem Trocknungszylinder (5) derart trägt, dass der Riemen (16) mit der Faserbahn (1) an der Oberfläche des Trocknungszylinders (5) in Eingriff gelangt, dadurch gekennzeichnet, dass, wenn der Riemen (16) mit der Faserbahn (1) durch die Presse (14, 10) tritt, die Vertiefungen (35) und die Oberflächenabschnitte (36) anfänglich auf der Faserbahn (1) ein äquivalentes Texturmuster ausbilden mit dickeren und dünneren Abschnitten, und wenn der Riemen (16) die Faserbahn zu dem Trocknungszylinder (5) trägt, die Oberflächenabschnitte (36) die dünneren Abschnitte der Faserbahn (1) an der Oberfläche des Trocknungszylinders (5) in Eingriff bringen und Wasser in den dickeren Abschnitten der Faserbahn (1) dazu gebracht wird, dass es verdampft.

14. Papiermaschine gemäß Anspruch 13, die des Weiteren eine zweite Presse aufweist, die stromaufwärtig der ersten Presse angeordnet ist, wobei die zweite Presse zwei Presselemente hat, die eine Saugpresswalze (13) und eine Gegenwalze (19) aufweisen zum Ausbilden eines Pressspaltes, wobei der Riemen (16) so eingerichtet ist, dass er mit der Faserbahn (1) durch die zweite Presse und die erste Presse tritt, und ein Pressenfilz (15) so angeordnet ist, dass er durch die zweite Presse und die erste Presse an der Faserbahn (1) läuft zum Aufnehmen von Wasser, das von der Faserbahn (1) gepresst wird, und wobei der Pressenfilz (15) so angeordnet ist, dass er von der Faserbahn (1) und dem Riemen (16) weg in einer Seitenschleife um die Saugpresswalze (13) und Führungswalzen (32, 6) geleitet wird.

15. Papiermaschine gemäß Anspruch 14, wobei der Pressenfilz (15) so angeordnet ist, dass er vor dem Langpressenspalt mit der Faserbahn (1) und dem Riemen (16) wieder zusammentrifft.

16. Papiermaschine gemäß einem der Ansprüche 14 oder 15, wobei Saugvorrichtungen innerhalb der Seitenschleife des Pressenfilzes (15) angeordnet sind, um die Fähigkeit des Pressenfilzes (15) zum Absorbieren von Wasser an dem Eingang zu dem Langpressenspalt zu erhöhen.

17. Papiermaschine gemäß einem der Ansprüche 13 bis 16, die des Weiteren eine Nasspartie (2) mit einem inneren Bahnbildungsgewebe (9) aufweist, wobei der Pressenfilz (15) um eine Aufnahmewalze (20) läuft, die nahe zu der Schleife des Gewebes (9) angeordnet ist und mit einem Saugschuh versehen ist.

18. Papiermaschine gemäß einem der Ansprüche 13 bis 16, die des Weiteren eine Nasspartie (2) mit einem inneren Bahnbildungsgewebe (9) aufweist, wobei der Pressenfilz (15) um einen Aufnahmesaugkasten herum läuft, der nahe zu der Schleife des Gewebes (9) angeordnet ist.

19. Papiermaschine gemäß einem der Ansprüche 13 bis 18, die des Weiteren eine Übertragungswalze (17) aufweist, die so eingerichtet ist, dass sie den Riemen (16) und eine Faserbahn (1) gegen die Oberfläche des Trocknungszylinders (5) in Eingriff bringt.

Revendications

1. Courroie de machine à papier destinée à faire avancer une bande de papier fibreuse humide (1) entre une presse (14, 19) et un cylindre sécheur chauffé (5) d'une machine à papier, dans laquelle la courroie (16) présente une surface en contact avec la bande, et est adaptée pour passer avec la bande fibreuse (1) à travers la presse (14, 19) et ensuite pour amener la bande fibreuse (1) jusqu'au cylindre sécheur (5), ladite surface en contact avec la bande définissant une multitude de dépressions réparties de manière régulière (35) et des parties de surface (36) situées entre lesdites dépressions (35), de telle sorte que la courroie (16) soit une courroie à texturer, en formant sur la bande fibreuse (1) un motif texturé équivalent, ladite courroie à texturer (16) ou une couche (34) de la courroie à texturer (16) destinée à être en contact avec la bande fibreuse (1), pouvant être comprimée de manière réversible de telle sorte que la courroie à texturer (16) soit comprimée dans une ligne de contact de transfert au niveau du cylindre sécheur (5) et reprenne son état non comprimé quand elle quitte ladite ligne de contact de transfert, caractérisée en ce que ladite courroie (16) est sensiblement imperméable, dans lequel la perméabilité à l'air de la courroie (16) est inférieure à 6 m³ / m² × minute, mesurée selon la procédure décrite dans le document « Standard Test Method for Air Permeability of Textile Fabrics, ASTM D 737 - 75, American Society of Testing and Materials ».

2. Courroie selon la revendication 1, dans laquelle un vide est créé dans les dépressions (35) lorsque la courroie à texturer (16) quitte la ligne de contact de transfert et reprend son état non comprimé.

3. Courroie selon la revendication 2, dans laquelle ledit vide contribue à la formation de vapeur dans les dépressions dans le motif de texturation, laquelle vapeur facilite à son tour la séparation de la courroie à texturer (6) de la bande de papier (1) après la ligne de contact de transfert, et également un séchage plus rapide de la bande de papier sur le cylindre sécheur (5).

4. Courroie selon l'une quelconque des revendications 2 et 3, dans laquelle l'effet de formation sous vide est commandé par l'élasticité de la courroie à texturer (16) du fait que plus l'effet de formation sous vide augmente, plus la compressibilité inverse est élastique.

5. Courroie selon l'une quelconque des revendications 1 à 4, dans laquelle la courroie présente un motif de texture qui est régulier.

6. Courroie selon la revendication 5, dans laquelle le motif de texture comprend un motif supplémentaire particulièrement saillant.

7. Courroie selon la revendication 6, dans laquelle le motif supplémentaire particulièrement saillant est sélectionné dans le groupe constitué par des images, des logotypes, des symboles commerciaux, et des symboles de société.

8. Courroie selon l'une quelconque des revendications 1 à 7, comprenant une couche arrière (33) et une couche (34) qui présente ladite surface en contact avec la bande qui comprend une couche polymère élastique qui peut être comprimée, qui présente une dureté qui se situe dans une plage comprise entre 50 Shore A et 97 Shore A, et qui définit ladite surface en contact avec la bande.

9. Courroie selon la revendication 8, dans laquelle ladite surface en contact avec la bande présente un degré de rugosité récupérable en réponse à une pression, dans un état non chargé, R_z, compris entre 2 µm et 80 µm, mesuré selon la norme ISO 4287, Part I, et un degré de rugosité plus faible, compris entre 0 µm et 20 µm, lorsque ladite couche polymère est comprimée par une charge linéaire comprise entre 20 kN / m et 200 kN / m quand on la mesure dans une ligne de contact de presse non étendue.

10. Courroie selon l'une quelconque des revendications 1 à 9, dans laquelle lesdites dépressions (35) occupent entre 20 % et 50 % de ladite surface en contact avec la bande.

11. Courroie selon l'une quelconque des revendications 1 à 10, dans laquelle lesdites dépressions sont des creux qui présentent des formes géométriques identiques ou similaires, y compris une forme circulaire, elliptique ou polygonale, la plus grande dimension de chacune d'elles se situant dans une plage comprise entre 0,5 mm et 3 mm, et la profondeur se situant dans une plage comprise entre 0,5 mm et 1 mm.

12. Courroie selon l'une quelconque des revendications 1 à 10, dans laquelle certaines au moins desdites dépressions sont des creux qui présentent des formes de symboles non géométriques, y compris des chiffres, des lettres, des symboles de commerce ou de société, avec des profondeurs qui se situent dans la plage comprise entre 0,5 mm et 1 mm.

13. Machine à papier destinée à traiter une bande de papier fibreuse humide (1), comprenant : la courroie de machine à papier (16) selon l'une quelconque des revendications 1 à 12 ; une section presse (3) qui comprend une première presse qui présente un rouleau presseur (14) et un contre-rouleau (19) de façon à former entre eux une ligne de contact de presse détendue de manière à presser la bande fibreuse (1), et à éliminer l'eau de la bande fibreuse (1) ; un cylindre sécheur chauffé (5) situé en aval de ladite première presse, destiné à recevoir la bande fibreuse pressée (1) autour d'une partie de la surface dudit cylindre sécheur (5), et à sécher en outre de ce fait la bande fibreuse (1) en faisant évaporer une partie au moins de l'eau qui reste dans la bande fibreuse (1), dans laquelle ladite courroie (16) est agencée de façon à faire passer la bande fibreuse (1) à partir de ladite première presse jusqu'audit cylindre sécheur (5) de telle sorte que ladite courroie (16) mette en prise la bande fibreuse (1) contre la surface dudit cylindre sécheur (5), caractérisée en ce que, lorsque la courroie (16) passe avec la bande fibreuse (1) à travers la presse (14, 10), lesdites dépressions (35) et lesdites parties de surface (36) forment au début sur la bande fibreuse (1) un motif texturé équivalent qui présente des parties plus épaisses et plus minces, et lorsque la courroie (16) fait passer la bande fibreuse jusqu'au cylindre sécheur (5), lesdites parties de surface (36) mettent en prise les parties plus minces de la bande fibreuse (1) contre la surface du cylindre sécheur (5) et l'eau présente dans les parties plus épaisses de la bande fibreuse (1) est contrainte de s'évaporer.

14. Machine à papier selon la revendication 13, comprenant en outre une seconde presse disposée en amont de ladite première presse, ladite seconde presse présentant deux éléments de presse qui comprennent un rouleau presseur à aspiration (13) et un contre-rouleau (19) de façon à former une ligne de contact de presse, dans laquelle ladite courroie (16) est agencée de façon à passer avec la bande fibreuse (1) à travers ladite second presse et ladite première presse, et un feutre de presse (15) agencé de façon à circuler à travers ladite seconde presse et ladite première presse contre la bande fibreuse (1), destiné à recevoir l'eau pressée en provenance de la bande fibreuse (1), et dans laquelle ledit feutre de presse (15) est agencé de façon à être conduit en s'éloignant de la bande fibreuse (1) et de la courroie (16) en une boucle latérale autour dudit rouleau presseur à aspiration (13) et des rouleaux de guidage (32, 6).

15. Machine à papier selon la revendication 14, dans laquelle ledit feutre de presse (15) est agencé de façon à rejoindre la bande fibreuse (1) et ladite courroie (16) avant la ligne de contact de presse étendue.

16. Machine à papier selon l'une quelconque des revendications 14 et 15, dans laquelle des dispositifs à aspiration sont agencés à l'intérieur de ladite boucle latérale du feutre de presse (15) de façon à accroître la capacité du feutre de presse (15) à absorber l'eau au niveau de l'entrée de ladite ligne de contact étendue.

17. Machine à papier selon l'une quelconque des revendications 13 à 16, comprenant en outre une section humide (2) qui présente une toile de formation intérieure (9), ledit feutre de presse (15) circulant autour d'un rouleau preneur (20) disposé à proximité de la boucle de ladite toile (9) et doté d'une semelle d'aspiration.

18. Machine à papier selon l'une quelconque des revendications 13 à 16, comprenant en outre une section humide (2) qui présente une toile de formation intérieure (9), ledit feutre de presse (15) circulant autour d'une caisse aspirante preneuse agencée à proximité de la boucle de ladite toile (9).

19. Machine à papier selon l'une quelconque des revendications 13 à 18, comprenant en outre un rouleau de transfert (17) agencé de façon à mettre en prise ladite courroie (16) et une bande fibreuse (1) contre la surface dudit cylindre sécheur (5).

Drawing