Flexible adjustable small-roller-diameter wide-pressing-area squeezing device

Abstract

The invention relates to a flexible adjustable small-roller-diameter wide-pressing-area squeezing device which comprises a roller pair and a shoe roller opposite to the roller pair, the shoe roller comprises a shoe sleeve and a shoe plate arranged in the shoe sleeve, the shoe plate is provided with a squeezing face in press fit with the roller pair, and the lowest point of the squeezing face in the vertical direction is located on one side of the shoe plate in the running direction of the shoe sleeve; a leakage structure is arranged on the shoe sleeve, and when the shoe plate and the roller are in press fit, liquid generated by squeezing can flow along the squeezing face and be discharged after reaching the squeezing face through the leakage structure. According to the designed flexible adjustable small-roller-diameter wide-pressing-area squeezing device, by adopting the small-roller-diameter boot rollers, the structure is more compact, meanwhile, a wide squeezing area is still constructed, especially under the low-speed condition, the dehydration performance of the squeezing device is remarkably improved, the defects of traditional roller type squeezing under the low-speed condition are effectively overcome, and the squeezing efficiency is improved. And a better choice is provided for the low-speed paper machine to produce high-quality paper.

Description

Technical Field

[0001] The invention relates to the technical field of pressing equipment, in particular to a flexible and adjustable small-roller-diameter wide-nip-area pressing device. Background Art

[0002] In the modern papermaking industry, the pressing process is a crucial link, which aims to remove moisture from wet paper sheets to the maximum extent and improve the fiber structure of paper sheets, thereby reducing the steam consumption of the subsequent drying process, improving production efficiency, and ultimately ensuring paper quality. At present, papermaking pressing technology is mainly divided into two categories: double-roll pressing and multi-roll composite pressing. Multi-roll composite pressing forms multiple pressure zones by connecting multiple pressing roller groups in series to achieve a more ideal dehydration effect. Its main forms include three-roll two-pressure zone, four-roll three-pressure zone and five-roll three-pressure zone composite pressing. The difference between these forms lies mainly in the number of pressing rollers.

[0003] In the double-roll pressing technology, there are many forms such as vacuum pressing, flat roll pressing, blind hole pressing, groove pressing, large roll diameter wide nip pressing and shoe pressing. Shoe pressing is currently recognized as the pressing technology with the highest dehydration efficiency. However, most of the existing pressing devices, including the various roll presses and shoe presses mentioned above, adopt a fixed roll diameter structure. Although these devices can meet the basic needs of paper production to a certain extent, their limitations are increasingly prominent when processing paper of different thicknesses and types. In recent years, with the growth of market demand for specialty paper, higher requirements have been placed on the flexibility and adaptability of pressing devices.

[0004] From a theoretical perspective, for different types of presses, when the pressing impulse (the product of the average pressure on the paper sheet in the press zone and the time of pressing) is the same, the final dryness of the paper web should be consistent. In order to maintain a certain pressing impulse at the same speed, it is necessary to extend the residence time of the wet paper sheet in the press zone. An effective way to extend the residence time is to increase the width of the press zone. However, for traditional roller-type linear narrow presses, the width of the press zone is usually only about 10 mm, and the space for increasing the line pressure is limited, usually only 150 KN / m or even lower. If the line pressure is forcibly increased, it is very easy to cause the paper sheet to collapse. Large roller diameter wide press attempts to increase the width and pressure of the press zone by increasing the diameter of the press roller, but the increase in roller diameter also leads to a significant increase in roller weight. For example, the diameter of the press roller of some paper machines has reached 1800 mm, and the weight of a single roller exceeds 50 tons, but the improvement in pressing efficiency is extremely limited. It can be seen that the technical path of simply relying on increasing the roller diameter to increase the nip width and nip pressure has reached a bottleneck.

[0005] As a wide-nip pressing technology, the shoe press has a nip width of 300-400mm and a line pressure of 1500KN / m, which is ten times higher than that of traditional pressing. Although the shoe press has excellent dehydration efficiency, its structure is extremely complex and the manufacturing cost is high. The existing shoe press device is based on the lubricating oil film principle, using lubricating oil to form an oil film between the shoe sleeve and the shoe plate, and applying pressure to the shoe plate through the hydraulic station. The whole system includes complex components such as the shoe plate, shoe sleeve, hydraulic station, thin oil station, cooling system, control system, etc., resulting in a complex structure and difficult maintenance. It is usually only suitable for high-speed paper machines. For low-speed paper machines, its cost performance is relatively low.

[0006] Ordinary pressing devices are still widely used on low-speed paper machines due to their simple structure and low cost. However, such devices are usually difficult to adjust according to different paper types and thicknesses, resulting in poor stability of product quality; if the line pressure is set too high, the pressure on the paper sheet is too great, which can easily cause problems such as crushing.

[0007] It is precisely because of the common problems of poor flexibility, poor adaptability and high cost of the above-mentioned existing pressing devices that they are unable to cope with the production of various specifications of paper. Especially in the field of high-quality paper production in the high-end market, traditional pressing devices often find it difficult to achieve ideal results, which seriously restricts the competitiveness and development space of enterprises. Summary of the invention

[0008] In order to solve the above problems, the present invention provides a flexible and adjustable small-roller-diameter wide-nip-zone pressing device that achieves efficient wide-nip-zone pressing with a compact structure and significantly improves dehydration efficiency and paper quality.

[0009] In order to achieve the above-mentioned purpose, the present invention designs a flexible and adjustable small-roller diameter wide pressure zone pressing device, comprising a pair of rollers and a boot roller arranged opposite to the pair of rollers, the boot roller comprising a boot sleeve and a boot plate built into the boot sleeve, the boot plate having a pressing surface pressed with the pair of rollers, the lowest point of the pressing surface in the vertical direction is located on one side of the boot plate in the running direction of the boot sleeve; the boot sleeve is provided with a leakage structure, wherein, when the boot plate is pressed with the pair of rollers, the liquid produced by the pressing reaches the pressing surface through the leakage structure, and can flow along the pressing surface to the lowest point and be discharged.

[0010] Preferably, the leakage structure is a plurality of openings arranged on the surface of the boot cover, and the openings penetrate the thickness of the boot cover.

[0011] Preferably, the boot roller also includes a shaft body, a wheel spoke and spokes, wherein the wheel spoke is movably mounted outside the shaft body along the axial direction of the shaft body, the spokes are connected to the outer edge of the wheel spokes and are distributed at intervals along the circumference of the shaft body, and an inclined surface is recessed in the middle of the spokes; wherein the boot sleeve is mounted on the outer side of the spokes.

[0012] Preferably, it further comprises a plurality of hydraulic devices arranged at intervals along the axial direction of the shaft body, wherein the hydraulic devices are connected to the shoe plate and are used to adjust the radial position of the shoe plate relative to the shaft body to change the pressing pressure between the shoe plate and the pair of rollers.

[0013] Preferably, the hydraulic device comprises a hydraulic cylinder, a pressure sensor and a control system, and the control system is used to control the action of the hydraulic cylinder according to a signal from the pressure sensor.

[0014] Preferably, the shoe plate has a guide surface, which extends downward from the lowest point of the pressing surface and smoothly transitions to the outer side of the spoke.

[0015] Preferably, it also includes a frame and a lifting device, the pair of rollers is arranged on the frame, the lifting device is arranged below the pair of rollers, the shoe roller is arranged on the lifting device, and the shoe roller is driven by the lifting device to move toward or away from the pair of rollers.

[0016] Preferably, a mounting seat is provided on the piston rod of the hydraulic cylinder, and the shoe plate is movably mounted on the mounting seat along the running direction of the shoe sleeve.

[0017] The flexible and adjustable small-roller-diameter wide-pressure-zone pressing device designed by the present invention adopts a small-roller-diameter boot roller, which is more compact in structure while still constructing a wide pressing area, effectively extending the residence time of paper in the pressing area and greatly improving the pressing and dehydration efficiency, especially under low vehicle speed conditions, the dehydration performance is particularly significantly improved, effectively making up for the shortcomings of traditional roller pressing under low speed conditions, and providing a better choice for low-speed paper machines to produce high-quality paper; at the same time, the pressing surface designed in this scheme, combined with the leakage structure on the boot sleeve, can effectively guide the water squeezed out during the pressing process to flow in a specific direction and be quickly discharged, reducing the retention of water in the pressing area, which can not only efficiently remove moisture from paper sheets, significantly reduce the risk of paper rewetting, and improve the strength, flatness and uniformity of paper, but also lubricate and cool the boot sleeve, reduce friction and wear, and extend the service life of the boot sleeve, thereby reducing maintenance costs and greatly improving the stability and reliability of the pressing process. In addition, while achieving high performance, the device maintains the simplicity of the overall structure and the controllability of costs, making it easier to transform and upgrade existing production lines, thereby bringing significant economic benefits and market competitiveness to papermaking companies. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of a flexible and adjustable small roller diameter and wide pressure zone pressing device provided in an embodiment of the present application.

[0019] Figure 2 It is a schematic diagram of the structure of the flexible and adjustable boot plate provided in an embodiment of the present application.

[0020] Figure 3 It is a schematic diagram of the coordination of the flexible and adjustable boot plate and the hydraulic cylinder structure provided in an embodiment of the present application.

[0021] Figure 4 It is a schematic diagram of the structure of the flexible and adjustable spokes provided in an embodiment of the present application.

[0022] Figure 5 It is a schematic diagram of the horizontal adjustment of the shoe plate position provided in an embodiment of the present application.

[0023] Among them: a pair of rollers 10, a shoe roller 20, a shaft 21, a spoke 22, a spoke 23, a shoe cover 30, a shoe plate 40, a pressing surface 41, a lowest point A, a guide surface 42, a hydraulic cylinder 50, a mounting seat 51, a frame 60, and a lifting device 70. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0025] The flexible and adjustable small roller diameter and wide nip pressing device described in this embodiment is intended to achieve a wide nip and efficient dehydration under a small roller diameter through a low-cost structural design. Figures 1 to 4 As shown, the device mainly includes a pair of rollers 10 and a shoe roller 20. In specific implementation, as Figure 4 As shown, the pair of rollers 10 is arranged on the frame 60 to provide support during pressing and can be driven to rotate by a motor, while the shoe roller 20 is arranged opposite to the pair of rollers 10 and can be moved toward or away from the pair of rollers 10 through the lifting device 70, thereby jointly constructing the required wide pressing zone to extend the pressing time of the paper in the pressing zone.

[0026] Specifically, the boot roller 20 includes a flexible boot cover 30 and a built-in rigid boot plate 40, wherein the boot plate 40 has a pressing surface 41 pressed against the counter-roll 10, and the radius of curvature of the pressing surface 41 usually accurately matches the curvature of the roller surface of the counter-roll 10 to ensure uniform and stable pressing contact between the two, and the lowest point A of the pressing surface 41 in the vertical direction is located on one side of the boot plate 40 in the running direction of the boot cover 30. At the same time, a leakage structure is provided on the boot cover 30, and when the boot plate 40 is pressed against the counter-roll 10, the liquid (mainly water) produced by the pressing reaches the pressing surface 41 through the leakage structure, and under the combined action of gravity and the pressing force, it naturally flows along the pressing surface 41 in the direction of the lowest point A, and is finally discharged from the lowest point A, thereby efficiently removing moisture from the paper and significantly reducing the possibility of moisture rewetting. In one embodiment, as Figure 1As shown, the shoe plate 40 is designed as an asymmetric wedge structure, that is, the inclination of the pressing surface 41 on it can effectively guide the squeezed water to flow in a specific direction, thereby avoiding water rewetting the paper and preventing a large amount of water from accumulating at the lowest point of the shoe plate 40.

[0027] In this way, through the design of the leakage structure on the boot sleeve 30, the squeezed water can penetrate to the surface of the boot plate 40, and a self-lubricating interface can be formed between the boot sleeve 30 and the boot plate 40, effectively reducing the friction resistance between the two, and taking away the heat generated by the friction, playing a significant cooling role, thereby avoiding overheating and wear of the boot sleeve, extending the service life of the boot sleeve, and improving the stability and reliability of the pressing process. The self-lubricating and cooling effects brought about by this leakage structure are different from the related art that constructs a complex hydraulic system in the boot roller 20 in order to construct a lubricating oil film between the boot sleeve and the boot plate, and does not require strict sealing performance requirements, which greatly simplifies the structure of the device and effectively reduces the manufacturing cost, making the flexible and adjustable small roller diameter wide pressure zone pressing device more economical and practical, and suitable for pressing rollers with a diameter of less than 600m, especially suitable for improving the pressing dehydration capacity and improving the paper forming quality at low vehicle speeds.

[0028] In some embodiments, the leakage structure is a plurality of openings arranged on the surface of the boot cover 30, and the openings penetrate the thickness of the boot cover 30. The penetrating openings can provide a direct drainage channel, so that the water squeezed out during the squeezing process can be discharged quickly and smoothly, reducing the retention of water in the squeezing area, thereby improving the dehydration efficiency, and the manufacturing process of the openings is simple, easy to implement, low cost, and will not significantly increase the complexity of the device. In a specific embodiment, the boot cover 30 is made of polyurethane rubber, and a micropore array with a pore size of 0.1-0.3mm is opened on its surface as a leakage structure.

[0029] In some embodiments, Figure 1 , Figure 2 , Figure 4 As shown, the shoe roller 20 further includes a shaft body 21, a wheel spoke 22 and a spoke 23, wherein the wheel spoke 22 is movably sleeved outside the shaft body 21 along the axial direction of the shaft body 21, and the spoke 23 is connected to the outer edge of the wheel spoke 22 and is distributed at intervals along the circumference of the shaft body 21, and the middle of the spoke 23 is concavely provided with an inclined surface; wherein the shoe cover 30 is sleeved on the outer side of the spoke 23. In actual use, by tensioning the shoe cover 30 through the wheel spoke 22 and the spoke 23, the diameter of the shaft body 21 can be effectively reduced while ensuring the structural strength, thereby reducing the overall weight of the shoe roller 20 and reducing the energy consumption of the equipment operation. At the same time, the structure of the wheel spoke 22 and the spoke 23 is conducive to air circulation, which can effectively reduce the temperature of the shoe roller 20 and ensure the stable operation of the equipment.

[0030] Furthermore, the shoe roller 20, that is, the shaft body 21, is provided with axially movable spokes 22, the outer sides of these spokes 22 are in contact with the spokes 23, and the inner sides of the middle parts of the spokes 23 in the length direction are inclined. When working, the shoe 30 is covered on the outside of the spokes 23; when the paper exerts an uneven force on the shoe cover 30, so that the roundness of the shoe roller 20 tends to change, the spokes 22 can move axially according to the force conditions. Since the inner sides of the spokes 23 are inclined, during the axial movement of the spokes 22, the spokes 23 will be stretched open, thereby increasing the tension on the shoe cover 30, so as to adjust the tension of the shoe cover 30, compensate for the uneven force of the paper, maintain the roundness and tension of the shoe cover 30, and ensure that the roundness of the shoe roller 20 always remains stable.

[0031] In some embodiments, Figure 2 , Figure 3 As shown, it also includes a plurality of hydraulic devices arranged at intervals along the axial direction of the shaft body 21, and the hydraulic devices are connected to the shoe plate 40 and are used to adjust the radial position of the shoe plate 40 relative to the shaft body 21 to change the pressing pressure between the shoe plate 40 and the pair of rollers 10.

[0032] Specifically, the hydraulic device includes a hydraulic cylinder 50, a pressure sensor and a control system, and the control system is used to control the action of the hydraulic cylinder 50 according to the signal of the pressure sensor. In this way, through the joint action of multiple hydraulic cylinders 50, the radial position of the shoe plate 40 relative to the shaft body 21 can be adjusted, and the pressure sensor monitors the pressure between the shoe plate 40 and the counter roller 10 in real time to reflect the change of the gap between the two, and feeds back the signal to the control system to help the operator control the action of the hydraulic cylinder 50 according to the thickness, material and pressing process requirements of the paper, so as to ensure that the pressing process is always in the best state.

[0033] In some embodiments, Figure 1 , Figure 2 As shown, the shoe plate 40 has a guide surface 42, which extends downward from the lowest point A of the pressing surface 41 and smoothly transitions to the outer side of the spoke 22. The smooth transition between the guide surface 42 and the outer side of the spoke 22 avoids abrupt structural changes, helps reduce stress concentration, and improves structural durability. It should be noted that in this embodiment, when the shoe plate 40 has a guide surface 42, as shown in FIG. Figure 2 As shown, the lowest point A of the pressing surface 41 is located at the end of the guide surface 42 .

[0034] In some embodiments, Figure 5 As shown, a mounting seat 51 is provided on the piston rod of the hydraulic cylinder 50, and the shoe plate 40 is movably mounted on the mounting seat 51 along the running direction of the shoe cover 30. In this way, the displacement adjustment of the shoe plate 40 in the horizontal direction can be achieved by the cooperation between the shoe plate 40 and the mounting seat 41 ( Figure 5 The position of the middle shoe plate 40 is only for adjustment indication), so that the operator can fine-tune the pressure distribution of the pressing area in the width direction according to the actual situation of the paper width direction, compensate for the unevenness of the paper width direction, and achieve uniform distribution of the pressing pressure in the width direction of the paper, so as to improve the uniformity of the paper dehydration effect, significantly improve the quality indicators of the paper such as flatness, uniformity, and strength, and ultimately improve the overall quality of the paper.

[0035] The flexible and adjustable small-roller-diameter wide-pressure-zone pressing device provided in the present embodiment adopts a small-roller-diameter boot roller, which is more compact in structure while still constructing a wide pressing area, effectively extending the residence time of paper in the pressing area and greatly improving the pressing and dehydration efficiency, especially under low vehicle speed conditions, the dehydration performance is particularly significantly improved, effectively making up for the shortcomings of traditional roller pressing under low speed conditions, and providing a better choice for low-speed paper machines to produce high-quality paper; at the same time, the pressing surface designed in this scheme, combined with the leakage structure on the boot sleeve, can effectively guide the water squeezed out during the pressing process to flow in a specific direction and be quickly discharged, reducing the retention of water in the pressing area, which can not only efficiently remove moisture from the paper sheets, significantly reduce the risk of paper rewetting, and improve the strength, flatness and uniformity of the paper, but also lubricate and cool the boot sleeve, reduce friction and wear, and extend the service life of the boot sleeve, thereby reducing maintenance costs and greatly improving the stability and reliability of the pressing process. In addition, while achieving high performance, the device maintains the simplicity of the overall structure and the controllability of costs, making it easier to transform and upgrade existing production lines, thereby bringing significant economic benefits and market competitiveness to papermaking companies.

[0036] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A flexible and adjustable small-roller-diameter wide-nip pressing device, comprising a pair of rollers and a shoe roller arranged opposite to the pair of rollers, wherein the shoe roller comprises a shoe sleeve and a shoe plate built into the shoe sleeve, characterized in that: The shoe plate has a pressing surface pressed with the counter-roll, and the lowest point of the pressing surface in the vertical direction is located on one side of the shoe plate in the running direction of the shoe sleeve; the shoe sleeve is provided with a leakage structure, wherein, when the shoe plate is pressed with the counter-roll, the liquid generated by the pressing reaches the pressing surface through the leakage structure, and can flow along the pressing surface to the lowest point and be discharged.

2. The flexible and adjustable small roller diameter wide nip pressing device according to claim 1 is characterized in that: The leakage structure is a plurality of openings arranged on the surface of the boot cover, and the openings penetrate the thickness of the boot cover.

3. The flexible and adjustable small roller diameter wide nip pressing device according to claim 1, characterized in that: The shoe roller also includes a shaft body, a wheel spoke and spokes, wherein the wheel spoke is movably mounted outside the shaft body along the axial direction of the shaft body, the spokes are connected to the outer edge of the wheel spokes and are distributed at intervals along the circumference of the shaft body, and the middle part of the spokes is recessed with an inclined surface; wherein the shoe sleeve is mounted on the outer side of the spokes.

4. The flexible and adjustable small roller diameter wide nip pressing device according to claim 3 is characterized in that: It also includes a plurality of hydraulic devices arranged at intervals along the axial direction of the shaft body, the hydraulic devices are connected to the shoe plate and are used to adjust the radial position of the shoe plate relative to the shaft body to change the pressing pressure between the shoe plate and the pair of rollers.

5. The flexible and adjustable small roller diameter wide nip pressing device according to claim 4, characterized in that: The hydraulic device includes a hydraulic cylinder, a pressure sensor and a control system, and the control system is used to control the action of the hydraulic cylinder according to the signal of the pressure sensor.

6. The flexible and adjustable small roller diameter wide nip pressing device according to claim 3, characterized in that: The shoe plate has a guide surface, which extends downward from the lowest point of the pressing surface and smoothly transitions with the outer side of the spoke.

7. The flexible and adjustable small roller diameter wide nip pressing device according to any one of claims 1 to 6, characterized in that: It also includes a frame and a lifting device, the pair of rollers is arranged on the frame, the lifting device is arranged below the pair of rollers, the shoe roller is arranged on the lifting device, and the shoe roller is driven by the lifting device to move toward or away from the pair of rollers.

8. The flexible and adjustable small roller diameter wide nip pressing device according to claim 5, characterized in that: A mounting seat is arranged on the piston rod of the hydraulic cylinder, and the shoe plate is movably mounted on the mounting seat along the running direction of the shoe sleeve.

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