Compression device and method for manufacturing kraft paper

Abstract

Compression device (21), in particular a Clupak device, and a method for compressing a fibrous web in a kraft paper manufacturing plant - wherein the compression device (21) has a ring-shaped compression belt (26), a compression belt drive (27) driving the compression belt (26), a counter roller (28), a counter roller drive (29) driving the counter roller (28), and a compression nip (30) formed between the compression belt (26) and the counter roller (28) - the compression device (21) has a compression mode in which it is operated in such a way that the fibrous web runs through the compression nip (30) at a production speed and is conveyed there between the running compression belt (26) and the running counter roller (28), while being compressed in the process in the machine running direction (1), and in which compression mode the compression belt (26) is driven by the compression belt drive (27).

Description

Technical Field

[0001] The present invention relates to a compression device, an apparatus, a method, and a type of kraft paper as described in the independent claim. Background Technology

[0002] In the existing technology, there are several known methods for manufacturing kraft paper. Kraft paper is a special type of paper, one of its characteristics being its extremely high strength. Due to this property, it is used in various packaging applications, such as the manufacture of paper bags. In addition to strength, other parameters, such as elongation or air permeability, are also crucial depending on the specific application of kraft paper.

[0003] When discussing the elongation of kraft paper, a distinction is usually made between elongation in the machine running direction and elongation perpendicular to the machine running direction, i.e., transverse elongation. To adjust the elongation in the machine running direction, a compression device is known to compress the fiber web passing through the manufacturing equipment in the machine running direction.

[0004] A widely used device for continuously compressing fiber webs along the machine's running direction is the so-called "Clupak device." In such a compression device, the fiber web is conveyed through a compression gap. One side of this compression gap is defined by a compression conveyor belt called a "compression belt," and the other side is defined by a drive roller. The compression belt is typically an endless, looping compression conveyor belt made of an elastic material, which is pressed against the drive roller in the compression gap region by a pressure beam. Passing the pressure beam, the elastic compression belt is squeezed between the opposing roller and the pressure beam, thereby locally reducing its thickness. After passing the pressure beam, the compression belt expands again, which causes local deceleration of the compression belt due to the lateral compression effect. The fiber web rests against the compression belt in this region, thus being compressed along the machine's running direction during the deceleration of the compression belt. The function and structure of such compression devices have been described in detail in the prior art. This invention also utilizes this function.

[0005] The disadvantage of the known compression devices of the above-described structural type is their relatively high maintenance costs. For example, due to the sliding in the pressure beam area and the opposing roller area, enormous frictional forces act on the compression belt. These frictional forces and relative motion lead to severe wear. In practice, this necessitates frequent maintenance or replacement of the compression belt.

[0006] During maintenance of the compression unit, the equipment cannot produce paper with the required properties because the compression unit cannot be used to process fiber webs. Even after maintenance, restarting the compression unit requires considerable effort. In conventional units, the compression belt is driven by contact with a drive roller on the other side of the compression gap. The stationary compression belt is pressed against the drive roller by a pressure beam, thus being driven. Therefore, this startup process takes a certain amount of time.

[0007] Because paper with the required parameters cannot be produced during maintenance, the efficiency of the compression unit decreases. Therefore, efforts have been made to design the components of the compression unit to be more robust, thereby extending maintenance intervals and improving the efficiency of the equipment. Summary of the Invention

[0008] In any case, one of the objectives of this invention is to improve the efficiency of kraft paper manufacturing equipment. However, this objective is achieved through a significantly different approach compared to existing technologies. The technical solution of this invention is particularly realized through the features of the independent claims.

[0009] In this compression device, unlike the usual configuration that uses a drive roller and a non-drive compression belt, the compression belt is also driven at the production speed. In the prior art, although there are known auxiliary drive devices for the compression belt that can reduce slippage between the compression belt and the drive roller when the compression device is started, these drive devices can only drive the compression belt at a low speed of up to 100 meters per minute at startup, and cannot reach the production speed.

[0010] However, this structure does not contain a drive roller in the traditional sense. Instead, it consists of a compression belt with a compression belt drive and an opposing roller with an opposing roller drive. The size and structural design of these two drive units enable them to drive the compression belt and the opposing roller at production speeds, preferably even when the clamping beam does not press the compression belt against the opposing roller, such as when there is no direct or effective contact between the compression belt and the opposing roller. The opposing roller may also be referred to as a Clupak cylinder or a heating cylinder in some cases, or perform similar functions.

[0011] In principle, this compression device can be divided into two operating modes: In compression mode, the fiber web passes through the compression gap, i.e., between the moving compression belt and the moving opposing rollers, at the production speed and is compressed in the machine's running direction. In this compression mode, the compression belt is driven by a compression belt drive unit. Preferably, the compression belt drive unit is a drive unit that acts directly on the compression belt via a compression belt drive roller. Preferably, in this compression mode, the opposing rollers are also driven by independent opposing roller drive units. Therefore, in this configuration, there are a total of two drive units and two driven rollers.

[0012] In free-running mode, the clamping beam is in the retracted position, thus preventing the compression belt from being pressed against the opposing roller, or at least reducing the clamping force. Preferably, even in free-running mode, the compression belt is driven by a compression belt drive device, and the opposing roller is driven by an opposing roller drive device.

[0013] These independent drive units enable the compression belt to be driven at production speed even when the pressure beam is in the retracted position and is not pressing the compression belt against the opposing roller.

[0014] Alternatively, the fiber web can also pass between the moving compression belt and the moving opposing roller in free-running mode. In this case, the compression belt is preferably driven by the compression belt drive device, and the opposing roller is driven by the opposing roller drive device. Preferably, the compression belt, opposing roller, and fiber web are driven at the production speed.

[0015] Surprisingly, this configuration has now been found to significantly improve the efficiency of equipment, processes, and compression units.

[0016] In this way, the speed of the compression belt and the opposing roller can be increased to the production speed without the compression belt contacting or pressing against the opposing roller. This helps reduce wear when the compression unit is started up and extends maintenance intervals.

[0017] Optionally, the fiber width can be produced at the compression device, even if the device is in free-running mode. During this process, the compression belt and opposing rollers can be driven at the production speed. When the compression device switches from free-running mode to compression mode, efficiency is improved through the components driven at production speed, namely the compression belt and opposing rollers.

[0018] Furthermore, when a paper breakage occurs in the equipment, the clamping beam can immediately, for example, within 2 seconds, preferably within 1 second, move to its retracted position, thereby switching the compression device from its compression mode to a free-running mode. In this case, the compression belt and the opposing roller can also continue operating at production speed without slippage between the opposing roller and the compression belt, which would otherwise lead to severe wear on the compression belt. This also further extends the maintenance interval and improves the efficiency of the equipment.

[0019] The present invention relates in particular to a compression device, especially a Clupak device, for compressing fiber webs in kraft paper manufacturing equipment.

[0020] Preferably, the compression device includes an annular compression belt, a compression belt drive device for driving the compression belt, a counter roller, a counter roller drive device for driving the counter roller, and a compression gap formed between the compression belt and the counter roller.

[0021] Preferably, the compression device has a compression mode in which the compression device operates as follows: the fiber web runs through the compression gap at the production speed and is conveyed between the running compression belt and the running opposing rollers, while being compressed along the machine running direction during this process.

[0022] Preferably, in compression mode, the compression belt is driven by a compression belt drive device.

[0023] Preferably, in compression mode, the opposing roller is driven by an opposing roller drive device, so that in compression mode, the compression belt and the opposing roller are each driven by their respective drive devices.

[0024] Optionally, the driving speeds of the compression belt drive and the opposing roller drive can be controlled or adjusted independently.

[0025] Optionally, it is specified that in compression mode, the running speed of the compression belt and the running speed of the opposing rollers are greater than 400 m / min, especially greater than 600 m / min, and substantially correspond to the production speed.

[0026] Optionally, a compression belt drive roller is provided, which transmits the driving torque of the compression belt drive device to the compression belt. In particular, the compression belt drive roller is in direct contact with the compression belt, and in addition to the opposing roller, a compression belt drive roller is additionally provided.

[0027] In particular, each of the two drive units undertakes more than 25% of the required drive power. Preferably, each of the two drive units undertakes about 50% of the required drive power. For example, the opposing roller drive unit undertakes about 50% to 75% of the required drive power.

[0028] Preferably, a tensioning roller is provided for tensioning the compression belt in compression mode.

[0029] Preferably, an adjustable clamping beam is provided inside the compression belt. In compression mode, the clamping beam displaces towards the opposing roller and presses the compression belt towards the opposing roller within the compression gap region. Specifically, in compression mode, the compression belt is compressed between the clamping beam and the opposing roller.

[0030] Alternatively, the compression device, as an alternative to the compression mode, has a free-running mode in which the pressure beam is in a retracted position relative to the compression mode, so that the compression belt does not apply pressure to the opposing roller, or applies a pressure reduced compared to the compression mode. In the free-running mode, the compression belt is driven by a compression belt drive, and the opposing roller is driven by an opposing roller drive.

[0031] Alternatively, the fiber web can also pass between the moving compression belt and the moving opposing roller in free-running mode. In this case, the compression belt is preferably driven by the compression belt drive device, and the opposing roller is driven by the opposing roller drive device. Preferably, the compression belt, opposing roller, and fiber web are driven at the production speed.

[0032] In free-running mode, the running speed of the compression belt and the running speed of the opposing roller are preferably greater than 400 m / min, especially greater than 600 m / min.

[0033] Optionally, it is specified that in compression mode, the clamping beam is squeezed toward the opposing roller with a force of at least 5 kN / m, especially at least 10 kN / m, especially at least 45 kN / m, preferably 5 kN / m or 10 kN / m or 40 kN / m to 70 kN / m.

[0034] Optionally, the thickness of the compression belt is specified to be greater than 15 mm, especially greater than 20 mm, preferably 20 mm to 30 mm.

[0035] Optionally, the compression belt is specified to have a compression width greater than 3.5 meters, especially greater than 5.5 meters, measured transversely to the machine's running direction.

[0036] Optionally, the Shore A hardness of the compression belt is between 40 and 70, especially between 50 and 60.

[0037] Optionally, in compression mode, the opposing rollers are heated.

[0038] Optionally, the opposing rollers are heated with a steam pressure of 2 to 15 bar and / or a temperature of 70°C to 180°C.

[0039] This invention particularly relates to a kraft paper manufacturing apparatus, which includes the following components: - The headbox section is used to continuously apply a fiber suspension along the machine's running direction to form a fiber web. - A shaking device is used to make the fiber web transverse to the machine's running direction, i.e., to shake it transversely. - The pressing section is used to press the fiber web that has been partially dehydrated in the web section. -Drying section, used for drying fiber fabric webs. - A winding station used to wind up a paper web formed from fiber material. - and compression device.

[0040] Preferably, the drying section includes a pre-drying section and a post-drying section.

[0041] Optionally, a compression device is disposed between the pre-drying section and the post-drying section, and compresses the fiber web between the pre-drying section and the post-drying section in the machine running direction.

[0042] Optionally, when the dry content of the fiber web is 55% to 70%, the compression device compresses the fiber web.

[0043] The present invention particularly relates to a method for manufacturing kraft paper, wherein the fiber web of the kraft paper manufacturing equipment is compressed in a compression device, wherein the compression device is particularly configured as a Clupak device.

[0044] The steps can be: - The circular compression belt is driven by a compression belt drive device. - The opposing rollers are driven by the opposing roller drive device. - In the compression mode of the compression device, the fiber width is... Production speed is achieved through a compression gap set between the compression belt and the opposing rollers, where the material is conveyed between the moving compression belt and the moving opposing rollers, and compressed along the machine's running direction during this process. Furthermore, the compression belt is driven by a compression belt drive device in compression mode.

[0045] Optionally, the fiber web can be conveyed at production speed through the compression device, even if the device is in free-running mode. In this case, the compression belt and the opposing roller can be driven at production speed. If the compression device switches from free-running mode to compression mode during this process, the compression belt driven at production speed is pressed against or toward the opposing roller, wherein the fiber web conveyed at production speed runs between the compression belt and the opposing roller.

[0046] Similarly, the compression device can also be switched from compression mode to free-running mode. In this case, the compression belt, the opposing rollers, and especially the fiber width can all be driven by production speed.

[0047] Therefore, the compression function of the fiber web can be flexibly enabled or disabled by the compression device without stopping production or reducing the production line speed.

[0048] According to a preferred embodiment, in free-running mode, the compression belt should maintain a certain distance from the opposing roller.

[0049] According to a preferred embodiment, when the fiber web passes through the compression device in free-running mode, it should be pressed against the opposing rollers.

[0050] Further methodological steps may include: - In the headbox section, a fiber suspension is continuously sprayed along the machine's running direction through a headbox to form a fiber web. - The fiber web is vibrated laterally in a direction perpendicular to the machine's running direction using a vibrator. - In the pressing section, the fiber web, which has already undergone partial dehydration in the web section, is pressed. - The fiber web is dried in the drying section. - In the winding station, the paper web formed from the fiber web is wound up.

[0051] It is beneficial to have a drying section that includes a pre-drying section and a post-drying section.

[0052] It would be beneficial if the compression device could compress the fiber width between the pre-drying section and the post-drying section along the machine's running direction.

[0053] When the dry content of the fiber web is between 55% and 70%, it is beneficial to compress the fiber web using a compression device.

[0054] The present invention particularly relates to a kraft paper manufactured on the said device and / or by the said method.

[0055] This invention relates to a method for manufacturing kraft paper, particularly kraft paper for bags, wherein a fiber web extending in the machine's running direction is formed in the first step. This is specifically achieved by spraying a fiber suspension onto the wire section from a headbox.

[0056] Specifically, after the suspension is sprayed onto the web, the fiber material is shaken or vibrated by a high-frequency shaking device at the breast roller. This helps to reduce the orientation of the fibers in the machine's running direction and increase their orientation in the transverse direction.

[0057] In the mesh section, fiber belts or sheets are formed through a filtration process, especially when using a dewatering device.

[0058] In particular, a pressing section is located immediately following the web section, where the fiber web can be mechanically dewatered and compressed simultaneously. This is typically achieved through multiple pressing zones, where the first pressing zone is usually designed as a vacuum press with double felt guides, while the others are designed as roller presses or shoe presses, which are equipped with double felt or single felt guides.

[0059] The fiber web after mechanical pressing can undergo one or more drying processes to adjust to the desired dry content. Further manufacturing and / or processing steps, such as compressing or calendering the fiber web, can be set before, between, or after one or more drying processes.

[0060] Compression of the fiber web can be particularly effective between two drying steps, namely, after the pre-drying step in the pre-drying section and before the post-drying step in the post-drying section. This increases the paper's elongation in the machine direction. This step is carried out in the compression unit.

[0061] For example, the fiber web can be calendered or embossed after the final drying step, with calendering performed using hot rollers or embossing rollers. Hot rollers are used to provide the smoothest possible paper surface, while embossing rollers are used to give the paper surface a different appearance.

[0062] After the final processing step, the paper web can be rolled up in the winding section and then further processed into the required finished roll width.

[0063] The production speed of the equipment and / or compression device is preferably greater than 400 meters per minute. The width of the fiber web or the produced paper web is preferably greater than 3.5 meters, especially greater than 5.5 meters, and usually greater than 6.0 meters.

[0064] The width of the compression belt and the opposing roller shall be at least 4.0 meters, especially at least 7.0 meters, and usually at least 8.0 meters.

[0065] Optionally, the production speed is at least 600 m / min, especially at least 1000 m / min or at least 1100 m / min.

[0066] Specifically, the fiber raw material used to produce kraft paper is pulp made from long fibers of softwood. The pulp has a kappa value of at least 30. The resulting kraft paper can be, in particular, unbleached brown kraft paper.

[0067] The transverse elongation of the kraft paper is preferably greater than 5%, more preferably greater than 7.5%, and especially conforms to the ISO 1924-3:2005 standard. These values ​​should also ideally be achieved in the direction of machine travel.

[0068] Preferably, the width of the kraft paper web is greater than 3.5 meters, especially greater than 5.5 meters, for example greater than 6.0 meters. In the context of this invention, width specifically refers to the dimension of the paper web in the transverse direction.

[0069] Preferably, the maximum difference in elongation between the edge region and the center region of the paper web in the transverse direction is 1.5%. In absolute terms, depending on the production process, the elongation of the center region can be between 5% and 8%, and the elongation of the edge region can be between 7.5% and 12%. Specifically, the edge region refers to a 50 cm wide area measured from each outer edge of the paper web. The center region specifically refers to a 50 cm wide area distributed 25 cm to each side of the geometric center in the width direction of the paper web.

[0070] An exemplary way to measure elongation is to perform the measurement between 0.75 and 1.5 hours after kraft paper production (i.e., after the final manufacturing process), typically 1.0 hour. However, the measurement can optionally be performed at a later or earlier time.

[0071] Optionally, the Ambertec uniformity of the paper is up to 0.7 √ (g / m²).

[0072] Optionally, the paper’s glyphic air resistance (especially according to ISO 5636-5:2013) is up to 15 seconds, preferably up to 10 seconds.

[0073] Optionally, the tensile energy absorption index of the paper in the machine orientation (MD) (especially according to ISO 1924-3:2005) is at least 2.5 J / g, preferably at least 3.0 J / g. Optionally, these values ​​also apply to the machine orientation of the paper.

[0074] Optionally, the fiber raw material contained in the paper is unbleached pulp.

[0075] Alternatively, bleached pulp can also be used.

[0076] Optionally, the fiber raw material contained in the paper consists of long coniferous wood fibers with an average fiber length of at least 2 mm. In particular, fiber analysis can be performed according to ISO 16065-2:2014, for example, using an optical analysis with an L&W fiber analyzer.

[0077] Optionally, the kappa value of the fibers contained in the paper is at least 30, and more particularly at least 50.

[0078] The compression belt is preferably made of an elastomer material, which may selectively have a reinforcing structure. In particular, the compression belt can be designed as a conventional Clupak compression belt.

[0079] In all embodiments, the production speed is preferably the speed at which the fiber web enters the compression device.

[0080] Other features of the invention will be apparent from the description of the claims, drawings, and embodiments. Attached Figure Description

[0081] Figure 1a -c is a schematic diagram of the kraft paper manufacturing equipment according to the first embodiment of the present invention; and Figure 2 This is a detailed schematic diagram of the compression device.

[0082] Unless otherwise specified, the following features are shown in the figure: machine running direction 1, wire section 2, headbox 3, shaking device 4, press section 5, drying section 6, winding station 7, dewatering wire 8, outer side 9, breast roll 10, first dewatering section 11, inner side 12, second dewatering section 13, first dewatering device 14, second dewatering device 15, forming strip 16, water absorption zone 17, top forming dewatering wire 18, pre-drying section 19, post-drying section 20, compression device 21, calendering device 22, fiber web running direction 23, water absorption box 24, paper roll 25, compression belt 26, compression belt drive device 27, opposing roll 28, opposing roll drive device 29, compression gap 30, compression belt drive roll 31, tension roll 32, pressure beam 33, wrapping roll 34, wrapping angle 35, release agent output assembly or silicone oil spraying device 36, doctor blade 37, coolant nozzle 38. Detailed Implementation

[0083] The present invention will now be described in detail with reference to the embodiments.

[0084] Figure 1a -c shows a schematic general view of a kraft paper production apparatus according to a first embodiment of the present invention. The production line includes, in machine direction 1, a headbox 3, a wire section 2, a press section 5, a pre-drying section 19, a compression device 21, a post-drying section 20, a calendering device 22, and a winding station 7. The calendering device 22 may also be designed as an embossing device. The headbox 3 applies a fiber suspension to the continuously circulating dewatering wire 8 of the wire section 2 in a known manner, thereby forming a fiber web. As the system operates, the fiber web is continuously dewatered or dried and passes sequentially through the aforementioned equipment components. Finally, paper rolls 25 are formed, which can be transported and / or sent to subsequent processing steps.

[0085] In this embodiment, the production speed of the equipment is approximately 1100 meters per minute. The resulting paper width is approximately 6.4 meters.

[0086] The functions of each component are already familiar enough to those skilled in the papermaking industry, so they will not be described in detail here. The following description is specifically for wire section 2.

[0087] The fiber suspension from the headbox 3 is preferably coated onto the outer side 9 of the dewatering wire 8 of the wire section 2, thereby forming a fiber web. The machine running direction 1 or the direction of the paper being produced is consistent with the direction 23 of the fiber web.

[0088] The dewatering net 8 operates continuously around a plurality of rollers, and the application of the fiber suspension occurs in the area of ​​the breast roller 10 of the net section 2. An exemplary width of the dewatering net 8 is approximately 7.2 meters.

[0089] In this embodiment, the fiber raw material is, for example, pulp derived from coniferous wood, with an average fiber length of approximately 2.2 mm. Therefore, this falls under the category of so-called long fibers. The pulp is unbleached and has a kappa value of approximately 60. The concentration of the fiber suspension when sprayed onto the dewatering screen 8 is approximately 0.22%. However, bleached pulp can also be used.

[0090] The velocity of the fiber suspension flowing out of the headbox 3 is preferably about 2% higher than the operating velocity of the dewatering net 8. The operating velocity of the dewatering net 8 can reach about 1100 m / min.

[0091] The high-frequency shaking device 4 can be configured to shake the breast roll 10, thereby shaking the dewatering mesh 8 within the area of ​​the breast roll 10. This reduces the longitudinal alignment of fibers in the machine running direction 1, thus helping to improve the performance of the produced paper in the transverse direction, i.e., perpendicular to the machine running direction 1. In this embodiment, the shaking frequency is approximately 7 Hz and the amplitude is approximately 35 mm.

[0092] Viewed in the direction of travel 23, the fiber web enters the first dewatering section 11 after the suspension is sprayed onto the dewatering net 8. Here, the fiber web is dewatered downwards, that is, dewatering begins from the inner side 12 of the dewatering net 8. A first dewatering device 14 is arranged in the first dewatering section 11, which first dewaters the fiber web mainly under gravity, and then performs downward suction treatment. The suction treatment is carried out by a suction box 24.

[0093] In the first dewatering section 11, the fiber width is dewatered only downwards.

[0094] Following the first dewatering section 11 is the second dewatering section 13, where the fiber web is dewatered upwards, i.e., towards the upper side of the fiber web. For this purpose, a second dewatering device 15 is installed in the outer region 9 of the dewatering screen 8. This device is designed as a suction-type dewatering device with four consecutive suction zones 17. Between the second dewatering device 15 and the fiber web, there is an endlessly rotating top-forming dewatering screen 18 that rotates at the same speed as the main dewatering screen 8.

[0095] Preferably, four forming strips 16 are also arranged sequentially along the running direction 23 of the dewatering net 8. These forming strips apply pressure to the inner side 12 of the dewatering net 8, thereby pressing the fiber web against the top forming dewatering net 18 or the second dewatering device 15. The contact pressure generated by the forming strips 16 can be adjusted between 5 and 25 kPa.

[0096] Subsequently, the fiber web is output from the wire section 2 and, as shown in Figure 1, undergoes further processing in other parts of the equipment for further dehydration or drying, ultimately forming a paper web.

[0097] After processing in section 2, the resulting kraft paper exhibits a variety of excellent properties, especially in terms of transverse elongation and paper forming.

[0098] Kraft paper produced according to the embodiments has the following exemplary performance characteristics:

[0099] Figure 2 The diagram shows a compression device 21. The compression device 21 includes a compression belt 26. The compression belt 26 is an annular belt that wraps around multiple steering rollers or steering wheels. Specifically, the compression device 21 includes a compression belt drive roller 31 and a compression belt drive device 27. The compression belt drive device 27 drives the compression belt drive roller 31, which preferably directly contacts the compression belt 26 to drive the compression belt 26 in a circular motion.

[0100] The compression device 21 includes a pressure beam 33. This pressure beam 33 is designed to be movable and, in its current position, can press or abut against the opposing roller 28. In this embodiment, the opposing roller 28 has an opposing roller drive 29. Preferably, the opposing roller drive 29 and the compression belt drive 27 are independently controllable or adjustable drive devices, and, more preferably, are rotary drive devices. A compression gap 30 is formed between the compression belt 26 and the opposing roller 28. One side of the compression gap 30 is defined by the opposing roller 28, and the other side is defined by the compression belt 26.

[0101] The position of the compression device 21 shown in the figure basically corresponds to the compression mode in which the fiber web is compressed. In this compression mode, the fiber web passes through the compression gap 30 at a production speed and is conveyed between the moving compression belt 26 and the opposing roller 28, thereby being compressed along the machine running direction 1.

[0102] The compression belt 26 is driven in compression mode by the compression belt drive device 27.

[0103] The opposing roller 28 is driven by the opposing roller drive device 29 in compression mode, wherein in compression mode, the compression belt 26 and the opposing roller 28 are each driven by their own drive devices.

[0104] In compression mode, the rotational speed of the compression belt 26 and the rotational speed of the opposing roller 28 are preferably greater than 400 m / min, especially greater than 600 m / min, and substantially correspond to the production speed.

[0105] The compression belt drive roller 31 transmits the driving torque of the compression belt drive device 27 to the compression belt 26. Preferably, rollers 31, 34 and 39 function as guide rollers for the compression belt.

[0106] Because the compression belt 26 is pressed towards the opposing roller 28 by the pressure beam 33 in the compression gap 30 region, it is compressed between the pressure beam 33 and the opposing roller 28, thus reducing the thickness of the compression belt 26 in this region. After passing the pressure beam 33, the thickness of the elastically deformed compression belt 26 returns to its original thickness along the fiber web running direction 23. During this process, due to the lateral shrinkage effect, the compression belt 26 shrinks to a certain extent along its running direction, thereby locally reducing the speed of the compression belt 26. Since the fiber web is in contact with the compression belt 26 in this region, the fiber web is compressed by this effect. This compression occurs in the machine running direction 1. This process is preferably set by adjusting the wrapping roller 34 so that the contact time of the fiber web between the compression belt 26 and the opposing roller 28 can be adjusted by a wrapping angle of about 15° to 90°, preferably 20° to 45°.

[0107] As shown by the dotted line in the figure, by repositioning the clamping beam 33, the pressure or force acting on the compression belt 26 and the opposing roller 28 pointing in front of the clamping beam 33 can be reduced or completely eliminated. This release of the clamping beam 33 allows the compression device 21 to enter a free-running mode. In both compression and free-running modes, both drive devices can effectively drive the compression belt 26 and the opposing roller 28. Preferably, the operating speed of the drive devices should be substantially consistent with the production speed.

[0108] Preferably, the fiber web can also be conveyed between the moving compression belt 26 and the moving opposing roller 28 in free-running mode. Preferably, the compression belt 26 is also driven by the compression belt drive 27, and the opposing roller 28 is driven by the opposing roller drive 29. Preferably, the compression belt 26, the opposing roller 28, and the fiber web are driven at the production speed.

[0109] In this embodiment, the compression device 21 includes a tension roller 32. The tension roller 32 is used to maintain the tension of the compression belt 26. The tension roller 32 is preferably configured to be movable, for example, so that it can maintain the tension of the compression belt 26 when the compression belt 26 stretches due to wear.

[0110] Alternatively, when the pressure beam 33 retracts, the tension roller 32 can also maintain the tension of the compression belt 26.

[0111] In this embodiment, the compression device 21 includes a wrapping roller 34. The compression belt of the wrapping roller 34 is positioned such that the direction of the compression belt 26 extends along the outer contour of the opposing roller 28 for at least a certain range. Therefore, the position of the wrapping roller 34 determines the wrapping angle 35 of the compression belt 26 on the opposing roller 28. The larger the wrapping angle 35, the longer the contact distance of the compression belt 26, and the greater the contact distance of the fiber width on the opposing roller 28.

[0112] In this embodiment, the wrapping roller 34 is designed to be movable so that the wrapping angle 35 can be set or changed. When the wrapping roller 34 is moved, the tension roller 32 is preferably also movable so that it can compensate for the deviation of the compression belt 26 path caused by the movement of the wrapping roller 34. The adjustment positions of the wrapping roller 34 and the tension roller 32 are indicated by dashed lines. For example, the wrapping angle can be set or changed within the range of 15° to 90°, preferably 20° to 45°.

[0113] according to Figure 2The compression device 21 includes a release agent dispensing assembly, particularly a silicone oil spraying device 36, and preferably also includes a doctor blade 37. The silicone oil spraying device 36 applies the release agent to the surface of the opposing roller 28. This reduces the tendency of the fiber web to adhere to the opposing roller 28. Excess release agent can be scraped off and collected by the doctor blade 37. Specifically, multiple silicone oil spraying devices 36 can be provided to distribute the release agent across the entire width of the opposing roller 28.

[0114] In addition, a coolant nozzle 38 may be provided to supply coolant to the surface of the compression belt 26. Specifically, multiple coolant nozzles 38 are provided to distribute coolant across the entire width of the compression belt 26.

Claims

1. A compression device (21), particularly a Clupak device, for compressing the fiber web of a kraft paper manufacturing equipment. -in, The compression device (21) has an annular compression belt (26), a compression belt drive device (27) for driving the compression belt (26), a counter roller (28), a counter roller drive device (29) for driving the counter roller (28), and a compression gap (30) formed between the compression belt (26) and the counter roller (28). -The compression device (21) has a compression mode in which the compression device (21) operates as follows: the fiber web runs through the compression gap (30) at a production speed and is conveyed between the running compression belt (26) and the running opposing roller (28), while being compressed along the machine running direction (1) during this process. The feature is that, in the compression mode, the compression belt (26) is driven by the compression belt drive device (27).

2. The compression device (21) according to claim 1, characterized in that, In the compression mode, the opposing roller (28) is driven by the opposing roller drive device (29), so that in the compression mode, the compression belt (26) and the opposing roller (28) are driven by their respective drive devices.

3. The compression device (21) according to claim 1 or 2, characterized in that, The driving speeds of the compression belt drive device (27) and the opposing roller drive device (29) can be controlled or adjusted independently of each other.

4. The compression device (21) according to any one of claims 1 to 3, characterized in that, In the compression mode, the running speed of the compression belt (26) and the running speed of the opposing roller (28) are greater than 400 m / min, especially greater than 600 m / min, and substantially correspond to the production speed.

5. The compression device (21) according to any one of claims 1 to 4, characterized in that, A compression belt drive roller (31) is provided, which transmits the driving torque of the compression belt drive device (27) to the compression belt (26). In particular, the compression belt drive roller (31) is in direct contact with the compression belt (26). In addition to the opposing roller (28), a compression belt drive roller (31) is also provided.

6. The compression device (21) according to any one of claims 1 to 5, characterized in that, A tensioning roller (32) is provided for tensioning the compression belt (26) in compression mode.

7. The compression device (21) according to any one of claims 1 to 6, characterized in that, In particular, an adjustable pressing beam (33) is provided inside the compression belt (26). The pressing beam (33) is displaced toward the opposing roller (28) in the compression mode and presses the compression belt (26) toward the opposing roller (28) in the compression gap (30) area.

8. The compression device (21) according to claim 7, characterized in that, -The compression device (21) has a free-running mode that can replace the compression mode. - In the free-running mode, the clamping beam (33) is in a retracted position relative to the compression mode, whereby the compression belt (26) does not apply pressure to the opposing roller (28), or applies a reduced pressure to the opposing roller (28) relative to the compression mode. -In the free-running mode, the compression belt (26) is driven by the compression belt drive device (27), and the opposing roller (28) is driven by the opposing roller drive device (29).

9. The compression device (21) according to any one of claims 7 or 8, characterized in that, In the free-running mode, the running speed of the compression belt (26) and the running speed of the opposing roller (28) are greater than 400 m / min, especially greater than 600 m / min.

10. The compression device (21) according to any one of claims 7 to 9, characterized in that, In the compression mode, the clamping beam (33) presses towards the opposing roller (28) with a force of at least 5 kN / m, especially at least 10 kN / m, especially at least 40 kN / m, preferably from 10 kN / m to 70 kN / m or from 40 kN / m to 70 kN / m.

11. The compression device (21) according to any one of claims 1 to 10, characterized in that, - The thickness of the compression belt (26) is greater than 15 mm, especially greater than 20 mm, and preferably 20 mm to 30 mm. - and / or the compression belt (26) has a compression belt width greater than 3.5 meters, especially greater than 5.5 meters, measured transversely to the machine running direction (1). And / or the Shore A hardness of the compression belt (26) is between 40 and 60, especially between 50 and 60.

12. The compression device (21) according to any one of claims 1 to 11, characterized in that, - In the compression mode, the opposing roller (28) is heated. -In particular, the opposing roller (28) is heated with a steam pressure of 2 bar to 15 bar and / or a temperature of 70°C to 180°C.

13. A kraft paper manufacturing apparatus, comprising the following components: - The headbox (2) is used to continuously apply fiber material suspension along the machine running direction (1) through the headbox (3) to form a fiber material web. - A shaking device (4) is used to make the fiber web transverse to the machine running direction (1), that is, to shake it transversely. - Pressing section (5), used to press the fiber web that has been partially dehydrated in the web section (2). -Drying section (6), used for drying the fiber web. - A winding station (7) is used to wind up the paper web formed from the fiber web. - and the compression device (21) according to any of the preceding claims.

14. The device according to claim 13, characterized in that, - The drying section (6) includes a pre-drying section (19) and a post-drying section (20). - The compression device (21) is disposed between the pre-drying section (19) and the post-drying section (20), and compresses the fiber width between the pre-drying section (19) and the post-drying section (20) in the machine running direction (1).

15. The device according to claim 13 or 14, characterized in that: When the dry content of the fiber web is 55% to 70%, the compression device (21) compresses the fiber web.

16. A method for manufacturing kraft paper, wherein, The fiber web of the kraft paper manufacturing equipment is compressed in a compression device (21), wherein the compression device (21) is specifically configured as a Clupak device. -The annular compression belt (26) is driven by the compression belt drive device (27). -In this context, the opposing roller (28) is driven by the opposing roller drive device (29). -In the compression mode of the compression device (21), the fiber web runs at production speed through the compression gap (30) between the compression belt (26) and the opposing roller (28), and is conveyed therethrough between the running compression belt (26) and the opposing roller (28), while being compressed along the machine running direction (1) in the process, characterized in that: in the compression mode, the compression belt (26) is driven by the compression belt drive device (27).

17. The method according to claim 16, characterized in that: In the compression mode, the opposing roller (28) is driven by the opposing roller drive device (29), so that in the compression mode, the compression belt (26) and the opposing roller (28) are driven by their respective drive devices.

18. The method according to claim 16 or 17, characterized in that: The driving speeds of the compression belt drive device (27) and the opposing roller drive device (29) can be controlled or adjusted independently of each other.

19. The method according to any one of claims 16 to 18, characterized in that: In the compression mode, the running speed of the compression belt (26) and the running speed of the opposing roller (28) are both greater than 400 m / min, especially greater than 600 m / min, and substantially correspond to the production speed.

20. The method according to any one of claims 16 to 19, characterized in that: An adjustable pressing beam (33) is provided inside the compression belt (26). The pressing beam (33) moves toward the opposing roller (28) in the compression mode and presses the compression belt (26) toward the opposing roller (28) in the compression gap (30) area.

21. The method according to claim 20, characterized in that, -The compression device (21) has a free-running mode that can replace the compression mode. - In the free-running mode, the clamping beam (33) is retracted relative to the compression mode, so the compression belt (26) does not apply pressure to the opposing roller (28), or applies a reduced pressure to the opposing roller (28) relative to the compression mode. -In the free-running mode, the compression belt (26) is driven by the compression belt drive device (27), and the opposing roller (28) is driven by the opposing roller drive device (29).

22. The method according to any one of claims 20 or 21, characterized in that: In the free-running mode, the running speed of the compression belt (26) and the running speed of the opposing roller (28) are both greater than 400 m / min, especially greater than 600 m / min.

23. The method according to any one of claims 20 to 22, characterized in that: In the compression mode, the clamping beam (33) is clamped toward the opposing roller (28) with a force of at least 5 kN / m, especially at least 10 kN / m, especially at least 40 kN / m, preferably 40 kN / m to 50 kN / m.

24. The method according to any one of claims 16 to 23, characterized in that: The opposing roller (28) is heated in the compression mode. -In particular, the opposing roller (28) is heated with a steam pressure of 2 bar to 15 bar and / or a temperature of 70°C to 180°C.

25. The method according to any one of claims 16 to 24, characterized in that, - In the headbox (2), a fiber suspension is continuously applied along the machine running direction (1) through the headbox (3), thereby forming a fiber web. -The fiber web is shaken laterally in the machine's running direction (1) by a vibrator. - In the pressing section (5), the fiber web that has been partially dehydrated in the web section (2) is pressed. - In the drying section (6), the fiber web is dried. - In the winding station (7), the paper web formed from the fiber web is wound.

26. The method according to claim 26, characterized in that, - The drying section (6) includes a pre-drying section (19) and a post-drying section (20). - Furthermore, the compression device (21) compresses the fiber web between the pre-drying section (19) and the post-drying section (20) in the machine running direction (1).

27. The method according to any one of claims 17 to 27, characterized in that: When the dry content of the fiber web is 60% to 70%, the compression device (21) compresses the fiber web.

28. Kraft paper manufactured by the apparatus according to any one of claims 13 to 15, and / or manufactured by the method according to any one of claims 16 to 27.

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