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] Roller and pressing device

[0002] The invention relates to a roller for treating a material web according to the preamble of claim 1 and to a pressing device for a material web according to the preamble of claim 13.

[0003] During the production of material webs, such as textile webs, plastic films, metal webs, and especially fibrous webs such as paper webs, the material web is often passed 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.

[0004] However, under the influence of forces or temperature, these rolls deform to a certain extent. To ensure a homogeneous treatment nip, so-called deflection compensation rolls are used. A deflection compensation roll comprises a rotatable roll shell and internal hydraulic support elements that exert pressure on the roll shell from the inside, thereby influencing the roll profile and, consequently, the nip profile.

[0005] Such deflection compensation rollers are known in a variety of designs, materials and for different applications, and are described, for example, in the documents EP1760194 B1 or EP 0 720 698.

[0006] One application that has recently gained in importance is the production of specialty papers, particularly papers that are smooth on one side, so-called MG (machine glazed) papers. The paper web is guided over a large, steam-heated glazing cylinder, a so-called MG or Yankee cylinder. The systems usually comprise a treatment nip formed by the Yankee cylinder and a deflection compensation roll. A corresponding machine is described in the applicant's document EP 3 974 576. The application on the MG cylinder is particularly critical because it deforms very differently depending on the steam temperature. Steel cylinders are generally used, which are hard-coated to prevent corrosion. Therefore, re-grinding the contour of the MG cylinder is very difficult or even impossible.Compensating for deformations and thus leveling the treatment nip must therefore be done solely with the deflection compensation roller. Conventional deflection compensation rollers with a metallic shell, however, cannot compensate for deformations over such a wide range.

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

[0008] The inherent power of a hydraulically supported deflection compensation roller is very high, especially at high speeds. This power must be transferred to the plastic casing via an external drive. It has been shown that conventional transmission methods, such as a screw connection, do not work during continuous roller operation.

[0009] The object of the invention is to further develop the state of the art so that the rollers can be operated permanently and stably.

[0010] In particular, it is an object of the invention to improve the power transmission on the roll shell.

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

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

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

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

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

[0016] Typically, the roller shells are bolted to the drive flange. This is also easily possible with traditional deflection-control rolls made of steel or cast iron. However, the inherent performance of a hydraulically supported deflection-compensating roll is very high, especially at high speeds. This would result in the shell being damaged over time if the metal drive flanges were bolted to the plastic shell.

[0017] In a roller according to the present invention, an adhesive connection is therefore provided to connect the shell to the drive flange. This adhesive connection makes it possible to connect the drive flange to the shell over a large area, rather than only at the screw points as with screw connections. This ensures a more even load on the shell during power transmission, which can completely or largely prevent damage to the shell.

[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 casing or drive flange. It is particularly advantageous if the adhesive surface 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.

[0019] Alternatively or additionally, it is advantageous if the adhesive surface extends in the longitudinal direction of the roller over at least 30 mm, in particular at least 40 mm.

[0020] This allows a particularly durable adhesive bond to be achieved, as well as a particularly even load on the sheath during power transmission.

[0021] The drive flange can have a receptacle, for example a slotted receptacle, into which the casing is inserted. The adhesive surface(s) can then be located inside this receptacle.

[0022] In embodiments according to specific aspects of the invention, it can be provided that, in addition to the adhesive connection, further connecting means are provided, such as connecting pins or locking pins, which mechanically connect the jacket to the flange. This can be advantageous, for example, to fix the jacket in the right place while the adhesive dries, or if this is required by law, for example, as a safety measure. However, such pins do not lead to the damage to the jacket known from screw connections, since the power continues to be transmitted entirely or predominantly via the adhesive connection. The number of locking pins will usually be small, amounting to no more than 4, 8 or 12.

[0023] Suitable materials for the fasteners include metals, plastics or combinations thereof.

[0024] The connecting means are advantageously arranged in the region of an adhesive surface of the adhesive connection.

[0025] Epoxy resin adhesives, such as those sold under the product name Araldite®, have proven to be very suitable. The optimal selection of the adhesive depends on factors such as the specific shell / flange material combination, operating conditions, etc. The drive flanges can be connected to a drive, e.g., an electric motor, in a suitable manner.

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

[0027] In particular, it can be provided that the modulus of elasticity of the jacket 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 jacket 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 in the longitudinal direction is in the range between 10 GPa and 20 GPa.

[0030] A relatively soft shell along its length allows the roller to adapt very well to even large changes in its profile. A correspondingly low elastic modulus in the circumferential direction is unnecessary for this and is usually disadvantageous.

[0031] While the relatively soft plastic sheath is very advantageous for balancing, it can cause problems in other areas. For example, the underside of the sheath can deform under the corresponding load on the support elements and possibly be pushed into the gaps between adjacent support elements. Such load drops 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, in particular between 1 mm and 2 mm. Due to these small distances, a drop in load can be largely avoided.

[0033] In addition, it can 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 can 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 sheath.

[0035] In one embodiment, the roller shell can be made entirely of or based on a thermosetting plastic, referred to herein as "duroplast" for short, whereby fillers and / or reinforcing particles can additionally be embedded in the thermosetting plastic. Such a thermosetting plastic is particularly suitable for use at relatively high operating temperatures, especially compared to a thermoplastic.

[0036] In particularly preferred embodiments, the casing 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 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 may be advantageous if the matrix material to be used has a glass transition temperature of >140°C, preferably >170°C, to ensure dimensional stability during the production of the roll cover.

[0038] Such bodies can in particular be constructed from several layers, whereby the fibers in the different layers can be oriented differently.

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

[0040] Furthermore, the shell can also comprise a coating that provides the web-contacting surface of the roller, wherein this coating is composed in particular of a polyurethane. The coating can be designed as a hard or soft coating. The hardness can preferably be in the range of 10-20 P&J.

[0041] However, it should be noted that such a (glass) fiber-reinforced roller shell acts as an insulator. This means that only a minimal amount of heat can be conducted from the inside to the outside, nor from the outside to the inside, through the shell.

[0042] This can lead to problems with heat dissipation, particularly due to flexing in the applied coating. If this heat is not dissipated, it can lead to a weakening of the bond between the coating and the sheath body, and in extreme cases, to the coating detaching from the sheath body.

[0043] For this reason, it may be advantageous for the body to comprise a fiber material and a matrix material, wherein heat-conducting elements, in particular aluminum particles, are additionally incorporated into the matrix material.

[0044] The heat conduction elements allow the heat to be dissipated through the body into the interior of the roller, where it can be dissipated to the outside via an internal oil cooling system.

[0045] For example, to ensure stable operation at operating speeds of up to 2000 m / min, as well as to ensure the possibility of recoating the sleeve without using a winding mandrel, it is advantageous if the sleeve—in contrast to, for example, the press sleeve of a shoe press—has inherent rigidity that prevents deflection vibrations transverse to the treatment nip and exhibits only minimal inherent deflection when mounted in journals. This can be ensured—in addition to an appropriate winding structure of GRP and CFRP fibers—by a certain minimum wall thickness of the sleeve.

[0046] Advantageously, the sheath should have a thickness of more than 20mm, preferably more than 30mm.

[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 broadly. It encompasses the aforementioned combination of a (bending adjustment) roll and a counter roll, which is a heated Yankee cylinder, particularly a Yankee or MG cylinder.

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

[0050] In particular, the heated cylinder may have a surface that comprises or consists of a hard metal material, in particular a tungsten carbide-cobalt hard metal or a cermet material.

[0051] Due to the size of the Yankee cylinder and the fact that it is filled with steam, the cylinder often inflates. 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 in the edge areas, which would cause severe edge overloads without bending compensation of the counter roll. Particularly in Yankee cylinders with a hard metal coating, this deformation cannot be regularly corrected by grinding the Yankee cylinder when the operating parameters change. Therefore, the treatment nip must be compensated via the bending adjustment roll. This is always the case, for example, when the operating parameters, in particular the steam pressure, are changed. Since the deformation of the Yankee cylinder, for example,Since this can vary greatly depending on the paper grade produced, the deflection adjustment roll must be able to compensate for a wide range of nip disturbances. This can be achieved using a roll according to aspects of the invention and represents a significant customer benefit, as unwanted machine downtimes can be avoided.

[0052] However, the term pressing device also includes other applications.

[0053] As an example, calenders are used to treat paper and textile webs.

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

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

[0056] The figures show in detail:

[0057] Figure 1 shows a section of a roller according to one aspect of the invention

[0058] Figure 2a shows a section of a roller according to a further aspect of the invention

[0059] Figure 2b shows a section of a roller according to a further aspect of the invention

[0060] Figure 3 shows a pressing device according to one aspect of the present invention.

[0061] Figure 1 shows a section of a roller 1 with a shell 2 which is designed to be rotatable about an axis 4 passing through the shell 2. The axis 4 itself is not rotatable. The rotation of the shell 2 can take place via bearings 11 known per se, for example ball bearings 11 or roller bearings. A plurality of hydraulic support elements 3 are supported on the fixed axis 4. These can exert a force on the inner circumference of the shell. This exertion of force leads to a deformation of the shell 2, whereby the roller profile can be specifically adjusted. The support elements 3 are expediently arranged here along a row, with the distance A between two adjacent support elements 3 advantageously being less than 5 mm, in particular between 1 mm and 2 mm. Due to the small distances A, a drop in load between the support elements 3 can be largely avoided.

[0062] The width of the support elements 3 in the circumferential direction (ie, into the plane of the sheet) is preferably less than 100 mm, in particular 80 mm or less.

[0063] It should be noted that Figure 1 shows only a small section of a roller 1 at a drive-side or driver-side end of the roller 1. In practical applications, the extension of the roller 1 in the longitudinal direction L can be several meters, in particular 10 meters or more. In large rollers 1, significantly more support elements 3 are used than the three support elements 3 shown here as examples.

[0064] The roller 1 further has a drive flange 5. This drive flange 5 accommodates the casing 2 and transmits the power of an external drive (not shown in the figure) to the casing 2.

[0065] The drive flange(s) 5 are made of a metallic material, in particular steel. The casing 2, in contrast, is made of a plastic material. The casing 2 shown as an example in Figure 1 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 comprise a fiber material and a matrix material, wherein particles such as heat-conducting elements, in particular aluminum particles, can additionally be incorporated into the matrix material. In addition, this casing 2 comprises a coating 12, which provides the web-contacting surface of the roller 1, wherein this coating 12 can in particular be made of a polyurethane.

[0066] The connection between the casing 2 and the drive flange 5 is realized here via an adhesive bond. An adhesive is applied to an adhesive surface 6. This adhesive bond makes it possible to connect the drive flange 5 to the casing 3 over a wide area, rather than only at the screw points as with screw connections. This ensures a more even load on the casing 2 during power transmission, which can completely or largely prevent damage to the casing 2.

[0067] The drive flange 5 can, for example, as shown in Figure 1, have a receptacle, preferably a slot-shaped receptacle, into which the casing 2 is inserted. The adhesive surface 6 or adhesive surfaces 6, 6a can then be located inside this receptacle.

[0068] In this context, it is particularly advantageous if the adhesive surface 6 of the adhesive connection is relatively large and evenly distributed over the circumference of the casing 2 or the drive flange 5.

[0069] In particular, it is 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.

[0070] 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 to be achieved, as well as a particularly uniform load on the casing 2 during power transmission.

[0071] As will be readily apparent to a person skilled in the art, the roller 1 can be designed analogously on the opposite guide or drive side, in particular with regard to the mounting of the casing 2 in the corresponding drive flange 5.

[0072] Figures 2a and 2b show alternative implementations of the connection between drive flange 5 and casing 2 and correspond approximately to the region within the dashed circle in Figure 1. In the embodiment of Figure 2a, for example, an additional locking pin 7 is provided. This is inserted into a bore through the drive flange 5 and the casing 2. In this embodiment, the locking pin 7 is located in the area of ​​the adhesive surface 6. In particular, the locking pin 7 can also be glued to ensure a firm fit in the bore. In contrast to conventional screw connections between casing 2 and drive flange 5, almost no power is transmitted via the locking pins 7. Therefore, their number can be kept low. Figure 2b shows an embodiment in which a second adhesive surface 6a is provided.This second adhesive surface 6a can be provided in combination with a locking pin 7 as in Figure 2b, or alternatively.

[0073] Figure 3 shows a pressing device 10 according to a further aspect of the invention. The pressing device comprises a roller 1 according to one 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, usually heated with steam, for example a steel cylinder. The cylinder has a surface that often comprises or consists of a hard metal material, in particular a tungsten carbide-cobalt hard metal or a cermet material.

[0074] Due to the size of the Yankee cylinder 8, which can have a diameter of 3m - 8m, and the filling with steam, the effect of the cylinder 8 being inflated occurs. While the surface remains fixed at the end covers, it bulges outwards in the middle section. This is indicated in Figure 3 - greatly exaggerated. Furthermore (not shown here), the Yankee cylinder 8 is subject to thermal deformation, which leads to increased diameters, particularly in the edge areas, which would lead to severe edge overloads without bending compensation of the counter roll. Especially in Yankee cylinders 8 with a hard metal coating, this deformation cannot be regularly corrected by grinding the Yankee cylinder 8 when the operating parameters change. Therefore, the treatment nip 20 must be compensated via the bending adjustment roll 1. This, for example,is always the case when the operating parameters, in particular the steam pressure, are changed. Since the deformation of the Yankee cylinder 8, for example, can vary greatly depending on the type of paper produced, the bending adjustment roll 1 must be able to compensate for a wide range of nip disturbances. This represents a considerable advantage for the customer and unwanted machine downtimes are prevented. This is very easily possible with rolls 1 with a plastic jacket 2. In order to be able to transfer the high inherent power of a hydraulically supported bending compensation roll 1, particularly at high speeds, to the plastic jacket 2 via an external drive, it has been shown that the known transmission methods, such as a screw connection, do not work during continuous operation of the roll. For this reason, the connection between the jacket 2 and the drive flange 5 is realized entirely or partially via an adhesive connection.

[0075] List of reference symbols

[0076] 1 roller

[0077] 2 coats

[0078] 3 Support element

[0079] 4 axis

[0080] 5 Drive flange

[0081] 6 Adhesive surface

[0082] 6a second adhesive surface

[0083] 7 locking pin, connecting pin

[0084] 8 Yankee cylinders

[0085] 9 Material web

[0086] 10 Pressing device

[0087] 11 camps

[0088] 12 Coating

[0089] 20 treatment nip

[0090] A distance

[0091] L Longitudinal direction of the roller

Claims

Patent claims 1. Roller (1) for treating a material web (9), with a rotatable shell (2), wherein the roller (1) has a plurality of hydrostatic support elements (3) which can exert a force on the inner circumference of the shell (2), wherein the support elements (3) are supported on a non-rotating axis (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 constructed from plastic material, while the drive flange(s) (5) are constructed from a metallic material, in particular from steel, characterized in that the connection of the shell (2) to the drive flange (5) is realized entirely or partially via an adhesive connection.

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

3. Roller (1) according to one of the preceding claims, characterized 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, characterized in that the casing (2) comprises or consists of a body which is constructed from a fiber-reinforced plastic, in particular a glass-fiber-reinforced and / or carbon-fiber-reinforced plastic. Roller (1) according to claim 4, characterized in that the body comprises a fiber material and a matrix material, wherein heat-conducting elements, in particular aluminum particles, are additionally incorporated into the matrix material. Roller (1) according to one of claims 4 or 5, characterized in that a matrix material is used which has a glass transition temperature of >140°C, in particular >170°C. Roller (1) according to one of the preceding claims, characterized 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, than in the longitudinal direction (L) of the roller (1). Roller (1) according to one of the preceding claims, characterized in that the support elements (3) are arranged along a row, wherein the distance (A) between two adjacent support elements (3) is less than 5 mm, in particular between 1 mm and 2 mm.Roller (1) according to one of the preceding claims, characterized in that the width of the support elements (3) in the circumferential direction is less than 100 mm, in particular 80 mm or less. Roller (1) according to one of the preceding claims, characterized in that the casing (2) additionally comprises a coating (12) which provides the web-contacting surface of the roller (1), wherein this coating (12) is composed in particular of a polyurethane. Roller (1) according to one of the preceding claims, characterized in that the casing (2) has a thickness of more than 20 mm, preferably more than 30 mm. Roller (1) according to one of the preceding claims, characterized in that in addition to the adhesive connection, further connecting means (7) are provided. in particular connecting pins (7) are provided which mechanically connect the casing (2) to the drive flange (5). 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 roller (1) and a counter-roller (8), characterized in that the roller (1) is designed according to one of the preceding claims. Pressing device (10) according to claim 12, characterized in that the counter-roller (8) is a heated cylinder (8), in particular a smoothing cylinder (8). Pressing device (10) according to claim 13, characterized 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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