Roll and press apparatus

Abstract

The invention relates to a roll and to a press apparatus for treating a material web, comprising a rotatable shell, wherein: the roll comprises a plurality of hydrostatic support elements which can exert a force onto the inner circumference of the shell; the support elements are supported on a non-rotating axle extending through the shell; a drive flange is provided on at least one end face of the roll, in particular one drive flange is provided on each of the two end faces of the roll, in order to transmit a drive power to the shell; the shell is made of a plastic material, while the drive flange(s) is / are made of a metal material, in particular of a steel; and the connection of the shell to the drive flange is established completely or partially via an adhesive bond.

Description

[0001] The invention relates to a roller for treating a material web according to the preamble of claim 1 and a press device for a material web according to the preamble of claim 13.

[0002] In the production of material webs, such as textile webs, plastic films, metal webs, and especially fibrous webs like paper webs, the material web is frequently guided through so-called treatment nips to smooth, dewater, or compress the webs, for example. Such treatment nips usually consist of a roller and a counter element – ​​often a counter roller.

[0003] Under the influence of forces or temperature, these rollers deform to a certain extent. To nevertheless ensure a homogeneous treatment nip, so-called flexure compensation rollers are used. A flexure compensation roller comprises a rotatable roller shell and internal hydraulic support elements to exert pressure on the roller shell from the inside, thereby influencing the roller profile and consequently the nip profile.

[0004] Such bending compensation rollers are known in a variety of designs, materials and for various applications, and are described, for example, in documents EP1760194 B1 or EP 0 720 698.

[0005] One application that has recently gained importance is the production of specialty papers, in particular single-sided smooth papers, so-called MG (machine glazed) papers. In this process, the paper web is guided over a large, steam-heated glazing cylinder, a so-called MG or Yankee cylinder. The systems typically include a treatment nip formed by the Yankee cylinder and a bend compensation roller. A corresponding machine is described in the applicant's publication EP 3 974 576.

[0006] The application on the MG cylinder is particularly critical, as its deformation varies significantly depending on the steam temperature. Steel cylinders are typically used, which are hard-coated for corrosion protection. Therefore, re-grinding the contour of the MG cylinder is extremely difficult or even impossible. Compensating for the deformations and thus leveling the treatment nip must therefore be achieved solely via the bending compensation roller. However, conventional bending compensation rollers with a metallic casing cannot compensate for deformations within this wide range.

[0007] For this reason, EP 3 974 576 proposes using bending adjustment rollers with a plastic jacket. Such a jacket is more flexible than a steel or cast iron jacket and can therefore adapt better to the changing contour of the MG cylinder.

[0008] The power output of a hydraulically supported bending compensation roller is particularly high at high speeds. This power must be transferred to the plastic casing via an external drive. Experience has shown that known transmission methods, such as a bolted connection, do not work in continuous operation of the roller.

[0009] The purpose of the invention is to further develop the state of the art in such a way that the rollers can be operated in a permanently stable manner.

[0010] In particular, one object of the invention is to improve the power transmission on the roller shell.

[0011] Furthermore, it is an object of the invention to propose a pressing device for an MG machine that can be operated within a wide operating window.

[0012] The object of the invention is achieved by a roller according to claim 1 and a pressing device according to claim 13. Further advantageous embodiments of the present invention are found in the dependent claims. With regard to the roller, the object of the invention is achieved by a roller for treating a web of material, with a rotatable shell, wherein the roller has a plurality of hydrostatic support elements that can exert a force on the inner circumference of the shell, the support elements being supported on a non-rotating axis that penetrates the shell.

[0013] A drive flange is provided on at least one, and in particular both, end faces of the roller to transmit drive power to the shell. The shell is made of plastic material, while the drive flange(s) are made of a metallic material, in particular steel.

[0014] According to the invention, the connection of the casing to the drive flange is realized wholly or partially via an adhesive bond.

[0015] Such a roller is a bending adjustment roller.

[0016] The roller shells are typically bolted to the drive flange. This is also easily possible with classic bending adjustment rollers made of steel or cast iron. However, the inherent forces of a hydraulically supported bending compensation roller are very high, especially at high speeds. This would mean that a bolted connection between the metal drive flanges and the plastic shell would eventually damage the shell.

[0017] In a roller according to the present invention, an adhesive bond is therefore provided to connect the casing to the drive flange. This adhesive bond makes it possible to connect the drive flange to the casing over a flat area, instead of only at the screw points as with screw connections. This results in a more even load distribution on the casing during power transmission, thereby completely or largely preventing damage to the casing.

[0018] In this context, it is particularly advantageous if the adhesive surface of the adhesive bond is relatively large and evenly distributed over the circumference of the jacket or the drive flange.

[0019] It is particularly advantageous if the adhesive surface extends around the entire circumference. This can be in the form of a closed ring or in the form of one or more spirals.

[0020] Alternatively or additionally, it is advantageous if the adhesive surface extends at least 30 mm, and in particular at least 40 mm, in the longitudinal direction of the roller. This ensures a particularly durable adhesive bond as well as a particularly even load distribution across the sleeve during power transmission. The drive flange can have a receptacle, for example a slot-shaped receptacle, into which the sleeve is inserted. The adhesive surface(s) can then be located inside this receptacle.

[0021] In embodiments according to specific aspects of the invention, it may be provided that, in addition to the adhesive bond, further connecting means, such as connecting pins or locking pins, are provided to mechanically connect the jacket to the flange. This can be advantageous, for example, to fix the jacket in the correct position while the adhesive dries, or if this is legally required as a safety measure. However, such pins do not cause the damage to the jacket known from screw connections, since the power is still transmitted entirely or predominantly via the adhesive bond. The number of locking pins will usually be small, not exceeding 4, 8, or 12.

[0022] Suitable materials for the fasteners include, for example, metals, plastics or combinations thereof.

[0023] The connecting elements are advantageously arranged in the area of ​​an adhesive surface of the adhesive joint.

[0024] Epoxy resin adhesives, such as those sold under the product name Araldite®, have proven to be very suitable as adhesives. The optimal choice of adhesive depends on factors such as the specific material combination of the sleeve / flange, the operating conditions, etc.

[0025] The drive flanges can be connected to a drive, e.g. an electric motor, in a suitable manner, as is known in the ordinary.

[0026] In advantageous embodiments, it can be provided that the modulus of elasticity of the shell in the circumferential direction of the roller is larger, preferably twice as high, in particular at least five times as high, as in the longitudinal direction of the roller.

[0027] In particular, it can be provided that the modulus of elasticity of the shell in the longitudinal direction is a maximum of 50 GPa, preferably a maximum of 20 GPa.

[0028] Furthermore, it can be provided that the modulus of elasticity of the shell in the longitudinal direction is at least 5 GPa, preferably at least 10 GPa.

[0029] It can be advantageous if the elastic modulus of the shell is in the longitudinal direction in the range between 10 GPa and 20 GPa.

[0030] Thanks to its relatively soft longitudinal surface, the roller can adapt very well to even significant changes in profile. A correspondingly low modulus of elasticity in the circumferential direction is therefore unnecessary and generally even disadvantageous.

[0031] While the relatively soft plastic sheath is very advantageous for leveling, it can cause problems elsewhere. For example, the underside of the sheath can deform under the load on the support elements and potentially be forced into the spaces between adjacent support elements. Such load breaks can later be visible in the produced material web. To enable a wide range of applications, it is advantageous to design the support elements appropriately.

[0032] It can be particularly advantageous if the support elements are arranged along a row, with the distance between two adjacent support elements being less than 5 mm, especially between 1 mm and 2 mm. These small distances largely prevent load dips.

[0033] Furthermore, it may be provided that the width of the support elements in the circumferential direction is less than 100 mm, in particular 80 mm or less, since otherwise the hydrostatic gap formation may be impaired due to the shell deformation - which is strong compared to the metal.

[0034] Various plastics can be suitable for the material of the casing.

[0035] The roller shell can be made entirely from or based on a thermosetting plastic, referred to here as thermoset, in which fillers and / or reinforcing particles may also be embedded. Such a thermosetting plastic is particularly suitable for use at relatively high operating temperatures, especially compared to a thermoplastic plastic.

[0036] In particularly preferred embodiments, the sheath may comprise or consist of a body made of a fiber-reinforced plastic, in particular a glass fiber reinforced plastic (GFRP) or a carbon fiber reinforced plastic (CFRP). A hybrid form of glass fiber and carbon fiber reinforced plastics is also conceivable.

[0037] In principle, all matrix materials known from the prior art are suitable. However, it can be advantageous if the matrix material to be used has a glass transition temperature of >140°C, preferably >170°C, in order to ensure dimensional stability during the production of the roller covering.

[0038] Such bodies can be composed of several layers, in particular, with the fibers in the different layers being oriented differently.

[0039] By selecting the layer structure and orientation, the properties of the body or sheath can be precisely controlled. A further advantage of using such fiber-reinforced plastics is that thermal deformation of the sheath can be largely avoided.

[0040] Furthermore, it may be provided that the jacket also includes a coating which provides the web-contacting surface of the roller, this coating being made in particular of a polyurethane.

[0041] The coating can be either hard or soft. Preferably, the hardness should be in the range of 10-20 P&J.

[0042] However, it should be noted that such a (glass) fiber reinforced roller shell acts like an insulator. This means that only a minimal amount of heat can be conducted through the shell from the inside to the outside, nor from the outside to the inside.

[0043] This can lead to problems with heat dissipation, which arises particularly from flexing within the applied coating. If this heat is not dissipated, the bond between the coating and the casing can weaken, and in extreme cases, the coating can detach from the casing.

[0044] For this reason, it can be advantageous for the body to comprise a fiber material and a matrix material, with heat-conducting elements, in particular aluminum particles, also being incorporated into the matrix material.

[0045] The heat-conducting elements allow heat to be dissipated through the body into the interior of the roller, where it can be carried away to the outside via internal oil cooling.

[0046] To ensure stable operation at speeds up to 2000 m / min, and to allow for recoating of the jacket without the use of a winding mandrel, it is advantageous if the jacket—unlike, for example, the jacket of a shoe press—possesses inherent stiffness that prevents deflection vibrations perpendicular to the treatment nip and exhibits only minimal deflection when supported in journals. This can be achieved—in addition to a suitable winding structure of GRP and CFRP fibers—by ensuring a certain minimum jacket wall thickness. Advantageously, the jacket should have a thickness of more than 20 mm, preferably more than 30 mm.

[0047] Furthermore, a pressing device for a material web, in particular a paper web, is proposed, wherein the pressing device comprises a treatment nip formed by a roller and a counter roller. It is provided that the roller is designed according to one aspect of the invention.

[0048] The term "pressing device" is defined very generally. It encompasses the aforementioned combination of a (bending-adjusting) roller and a counter roller, which is a heated smoothing cylinder, in particular a Yankee cylinder or MG cylinder.

[0049] Within the scope of this application, the terms smoothing cylinder, MG cylinder, and Yankee cylinder are used synonymously unless explicitly stated otherwise. Such smoothing cylinders can, for example, have diameters of 3m to 8m.

[0050] In particular, the heated cylinder may have a surface comprising or consisting of a hard metal material, especially a tungsten carbide-cobalt hard metal or a cermet material.

[0051] Due to the size of the Yankee cylinder and its filling with steam, the cylinder often bulges. While the surface remains fixed at the end caps, it bulges outwards in the middle section. Furthermore, the Yankee cylinder is subject to thermal deformation, which leads to increased diameters, particularly at the edges. Without bending compensation from the counter-roller, this would result in severe edge overloads. Especially with Yankee cylinders featuring a carbide coating, this deformation cannot be regularly corrected by grinding the cylinder when operating parameters change. Therefore, the treatment nip must be compensated for via the bending adjustment roll. This is always the case, for example, when operating parameters, particularly steam pressure, are changed. Since the deformation of the Yankee cylinder, for example,Since the bending resistance can vary considerably depending on the type of paper being produced, the bending adjustment roller must be able to compensate for a wide range of nip disturbances. This can be achieved using a roller according to aspects of the invention and represents a significant customer advantage, as unwanted machine downtime can be avoided.

[0052] The term "pressing device" also encompasses other applications.

[0053] Calenders, which are used to treat paper and textile webs, are one example.

[0054] Furthermore, this term is also intended to encompass coating devices. For example, the pressing device could be a film press with which a starch film is transferred to one or both sides of the material web. In particular, bending adjustment rollers according to aspects of the present invention can be used in the area of ​​so-called 'hard nip sizing'. In this context, the bending adjustment roller and / or the counter roller can, in particular, have a hardness of more than 60 Shore D, especially between 80 and 95 Shore D.

[0055] The invention will be explained below with reference to figures. However, the invention is not limited to these illustrations.

[0056] The figures show, in detail: Figure 1 shows a section of a roller according to one aspect of the invention. Figure 2a shows a section of a roller according to a further aspect of the invention. Figure 2bshows a section of a roller according to a further aspect of the invention. Figure 3 shows a pressing device according to one aspect of the present invention.

[0057] Figure 1 Figure 1 shows a section of a roller 1 with a shell 2, which is designed to rotate about an axis 4 passing through the shell 2. The axis 4 itself is not rotatable. The rotation of the shell 2 can be effected by means of bearings 11 known per se, for example ball bearings 11 or roller bearings.

[0058] A plurality of hydraulic support elements 3 are supported on the stationary axis 4. These elements can exert a force on the inner circumference of the shell. This force causes a deformation of the shell 2, allowing the roller profile to be precisely adjusted. The support elements 3 are advantageously arranged in a row, with the distance Δ between two adjacent support elements 3 being less than 5 mm, particularly between 1 mm and 2 mm. These small distances Δ largely prevent load dips between the support elements 3.

[0059] The width of the support elements 3 in the circumferential direction (i.e., 'into the plane of the sheet') is preferably less than 100mm, in particular 80mm or less.

[0060] It should be noted that in Figure 1Only a small section of a roller 1 is shown at a drive-side or operator-side end of the roller 1. The longitudinal extent L of the roller 1 can be several meters in practical applications, particularly 10 m or more. In large rollers 1, significantly more support elements 3 are used than the three support elements 3 shown here as an example.

[0061] The roller 1 further has a drive flange 5. This drive flange 5 accommodates the shell 2 and transmits the power of an external drive (not shown in the figure) to the shell 2.

[0062] The drive flange(s) 5 are made of a metallic material, in particular steel. The casing 2, on the other hand, is made of a plastic material. The in Figure 1The exemplary jacket 2 comprises, for example, a body made of a fiber-reinforced plastic, in particular a glass fiber-reinforced and / or carbon fiber-reinforced plastic. Such fiber-reinforced plastics generally have a fiber material and a matrix material, whereby particles such as heat-conducting elements, in particular aluminum particles, may also be incorporated into the matrix material. Furthermore, this jacket 2 includes a coating 12, which provides the web-contacting surface of the roller 1, and which may in particular be made of polyurethane.

[0063] The connection between the casing 2 and the drive flange 5 is achieved here via an adhesive bond. An adhesive is applied to an adhesive surface 6.

[0064] The adhesive bond makes it possible to connect the drive flange 5 to the casing 3 over its entire surface, instead of only at the screw points as with screw connections. This results in a more even load distribution on the casing 2 during power transmission, thus preventing or largely preventing damage to the casing 2.

[0065] The drive flange 5 can, for example, be configured as shown in Figure 1 The figure shown has a receptacle, preferably a slot-shaped receptacle, into which the sheath 2 is inserted. The adhesive surface 6 or adhesive surfaces 6, 6a can then be located inside this receptacle.

[0066] In this context, it is particularly advantageous if the adhesive surface 6 of the adhesive joint is relatively large and evenly distributed over the circumference of the jacket 2 or the drive flange 5.

[0067] It is particularly advantageous if the adhesive surface 6 extends around the entire circumference. This can be realized in the form of a closed ring or in the form of one or more spirals.

[0068] Alternatively or additionally, it is advantageous if the adhesive surface 6 extends in the longitudinal direction L of the roller 1 over at least 30 mm, in particular at least 40 mm. This allows for a particularly durable adhesive bond as well as a particularly uniform load distribution on the casing 2 during power transmission.

[0069] As can be easily seen by a person skilled in the art, the roller 1 on the opposite driver or drive side can be designed analogously, in particular with regard to the mounting of the jacket 2 in the corresponding drive flange 5.

[0070] The Figures 2a and 2bThe figures show alternative realizations of the connection between drive flange 5 and casing 2 and correspond approximately to the region within the dashed circle. Figure 1 . During the execution of the Figure 2a For example, an additional locking pin 7 is provided. This pin is inserted into a bore through the drive flange 5 and the casing 2. In this design, the locking pin 7 is located in the area of ​​the adhesive surface 6. The locking pin 7 can also be bonded to ensure a secure fit in the bore. Unlike conventional screw connections between the casing 2 and the drive flange 5, virtually no power is transmitted via the locking pins 7. Therefore, their number can be kept to a minimum. Figure 2b Figure 1 shows an embodiment in which a second adhesive surface 6a is provided. This second adhesive surface 6a can be used as shown in Figure 2. Figure 2bin combination with a locking pin 7, or alternatively thereto.

[0071] Figure 3 Figure 1 shows a press device 10 according to a further aspect of the invention. The press device comprises a roller 1 according to another aspect of the invention. A Yankee cylinder 8 is shown here as the counter roller 8. Roller 1 and Yankee cylinder 8 form the treatment nip 9 for the material web 9, in particular a paper web 9. The Yankee cylinder 8 is a cylinder heated—usually with steam—for example, a steel cylinder, the cylinder having a surface that often comprises or consists of a hard metal material, in particular a tungsten carbide-cobalt hard metal or a cermet material.

[0072] Due to the size of the Yankee cylinder 8, which can have a diameter of 3m - 8m, and the filling with steam, the cylinder 8 experiences an inflation effect. While the surface remains fixed at the end caps, it bulges outwards in the middle section. This is in the Figure 3- greatly exaggerated - indicated. Furthermore (not shown here), the Yankee cylinder 8 is subject to thermal deformation, which leads to increased diameters, particularly in the edge regions. Without bending compensation by the counter roll, this would result in severe edge overloads. Especially with Yankee cylinders 8 with a hard metal coating, this deformation cannot be regularly corrected by grinding the Yankee cylinder 8 when operating parameters change. Therefore, the treatment nip 20 must be compensated for by the bending adjustment roll 1. This is always the case, for example, when the operating parameters, especially the steam pressure, are changed. Since the deformation of the Yankee cylinder 8 can vary considerably depending on the type of paper being produced, the bending adjustment roll 1 must be able to compensate for a wide range of nip disturbances.This represents a significant customer advantage and prevents unwanted machine downtime. This is easily achieved with rollers 1 featuring a plastic coating 2.

[0073] In order to transfer the high power output of a hydraulically supported bending compensation roller 1, especially at high speeds, to the plastic shell 2 via an external drive, it has been shown that known transmission methods, such as a screw connection, do not work during continuous operation of the roller. Therefore, the connection of the shell 2 to the drive flange 5 is realized wholly or partially via an adhesive bond. Reference symbol list

[0074] 1 Roller 2 Shell 3 Support element 4 Axle 5 Drive flange 6 Adhesive surface 6 Second adhesive surface 7 Locking pin, connecting pin 8 Yankee cylinder 9 Material web 10 Pressing device 11 Bearing 12 Coating 20 Treatment nip ΔDistance L Longitudinal direction of the roller

Claims

1. Roller (1) for treating a material web (9), having a rotatable shell (2), the roller (1) having a plurality of hydrostatic support elements (3) which can exert a force on the inner circumference of the shell (2), wherein the supporting elements (3) are supported on a non-rotating axle (4) passing through the shell (2), and wherein a drive flange (5) is provided on at least one, in particular both, end faces of the roller (1) in order to transmit a drive power to the shell (2), and wherein the shell (2) is made of plastic material, while the drive flange(s) (5) is / are made of a metallic material, in particular of steel, characterised in that the connection of the casing (2) to the drive flange (5) is realised in whole or in part by means of an adhesive connection.

2. Roller (1) according to claim 1, characterised in that the adhesive surface (6) of the adhesive connection extends around the entire circumference of the casing (2) or of the drive flange (5) and / or in that the adhesive surface (6) extends over at least 30 mm, in particular at least 40 mm, in the longitudinal direction of the roller (1).

3. Roller (1) according to one of the preceding claims, characterised in that the modulus of elasticity of the shell (2) in the longitudinal direction (L) is at most 50 GPa, preferably at most 20 GPa, and / or at least 5 GPa, preferably at least 10 GPa.

4. Roller (1) according to one of the preceding claims, characterised in that the shell (2) comprises or consists of a body which is constructed from a fibre-reinforced plastic, in particular a glass-fibre-reinforced and / or carbon-fibre-reinforced plastic.

5. Roller (1) according to claim 4, characterised in that the body comprises a fibre material and a matrix material, wherein heat-conducting elements, in particular aluminium particles, are additionally incorporated in the matrix material.

6. Roller (1) according to one of claims 4 or 5, characterised in that a matrix material is used which has a glass transition temperature of >140°C, in particular >170°C.

7. Roller (1) according to one of the previous claims, characterised in that the modulus of elasticity of the shell (2) in the circumferential direction of the roller (1) is greater, preferably twice as high, in particular at least five times as high, as in the longitudinal direction (L) of the roller (1).

8. Roller (1) according to one of the preceding claims, characterised in that the supporting elements (3) are arranged along a row, the distance (Δ) between two adjacent supporting elements (3) being less than 5mm, in particular between 1mm and 2mm.

9. Roller (1) according to one of the previous claims, characterised in that the width of the supporting elements (3) in the circumferential direction is less than 100 mm, in particular 80 mm or less.

10. Roller (1) according to one of the preceding claims, characterised in that the casing (2) also comprises a coating (12) which provides the surface of the roller (1) in contact with the web, this coating (12) being composed in particular of a polyurethane.

11. Roller (1) according to one of the preceding claims, characterised in that the shell (2) has a thickness of more than 20 mm, preferably more than 30 mm.

12. Roller (1) according to one of the previous claims, characterised in that, in addition to the adhesive connection, further connecting means (7), in particular connecting pins (7) are provided, which mechanically connect the casing (2) to the drive flange (5).

13. Pressing device (10) for a material web (9), in particular a paper web (9), wherein the pressing device (10) comprises a treatment nip (20) which is formed by a roll (1) and a counter-roll (8), characterised in that the roll (1) is designed in accordance with one of the previous claims.

14. Pressing device (10) according to claim 12, characterised in that the counter-roller (8) is a heated cylinder (8), in particular a smoothing cylinder (8).

15. Pressing device (10) according to claim 13, characterised in that the heated cylinder (8) has a surface which comprises or consists of a hard metal material, in particular a tungsten carbide-cobalt hard metal or a cermet material.

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