A pressing device for papermaking equipment

Abstract

The present invention discloses a pressing device for papermaking equipment, comprising: a supporting roller driven by a motor; a first shoe-type pressing roller abutting against one side of the supporting roller and rotating under the driving of the supporting roller, the first shoe-type pressing roller applies a first pressure to the supporting roller to form a first wide pressing area N1 for pressing a paper web between a bearing roller and the first shoe-type pressing roller; a second shoe-type pressing roller abutting against the other side of the supporting roller and rotating under the driving of the supporting roller, the second shoe-type pressing roller applies a second pressure for offsetting or partially offsetting the first pressure to the supporting roller to form a second wide pressing area N2 for pressing a paper web between the bearing roller and the second shoe-type pressing roller. The present invention can make the pressures on both sides of the supporting roller offset each other or offset most of each other, avoid the pressure deformation of the roller shell of the supporting roller, the roller shell and the bearing supporting its rotation will not bear the alternating stress caused by the flexural deformation of the roller shell, reduce the failure of cracking or breaking, and improve the reliability of the pressing device.

Description

Technical Field

[0001] The present invention relates to a papermaking device, in particular to a pressing device of the papermaking device, and its IPC classification belongs to D21F3 / 04. Background Art

[0002] In the press section of papermaking machinery that produces fiber webs, especially paper webs, the commonly used high-efficiency pressing technology is wide-nip pressing, also known as shoe pressing, to improve the dryness of paper webs. The book "Pulp and Paper Machinery and Equipment, Part 2" published by China Light Industry Press in 2003 has a detailed introduction to this technology. The average pressure of the 250-300mm long boot-shaped plate of the shoe press is equivalent to the line pressure of 1050kN / m by the normal pressing method, which is 8 times the pressing pressure of the traditional roller. The supporting roller of the matching shoe roller will bend and deform under such high pressure, which will lead to uneven pressure distribution on the entire transverse pressing contact surface. More seriously, the bearings supporting the rotation of the supporting rollers are subjected to alternating stress, and the bearings are prone to fatigue damage. In order to solve this problem, the existing technology usually adopts controllable middle and high rollers to obtain uniform pressure zone conditions under different pressing loads, and uses a built-in hydraulic device to form a fluid sliding bearing layer between the rotating roller shell and the fixed beam, which can form a flexible sliding bearing that adapts to the deflection deformation of the fixed beam. The mechanical bearing supporting the rotation of the roller shell is not affected by the deformation of the fixed beam, and the roller shell and the bearing supporting its rotation will not be subjected to alternating stress. Therefore, its roller shell and bearing are not prone to fatigue damage. However, the hydraulic control system is complex, costly, and difficult to maintain. In addition, the motor that drives the rotation of the controllable middle and high roller shell needs to overcome the sliding friction between the boot sleeve and the boot plate at the same time. 靴压 And the sliding friction f between the controllable middle and high roller shell and the built-in hydraulic device 背压 , the friction force f of the bearing supporting the roller shell 轴承 Etc., resulting in large motor power, and the total motor power of the system using double shoe pressure is doubled.

[0003] British Patent GB2218122B Figure 5 and Figure 6 The embodiment shown discloses a symmetrically arranged double-pressure zone device, which has a central long pressure zone pressure unit, wherein two wide pressure zones are arranged symmetrically relative to the axial plane of the central long pressure zone pressure unit, so that the reaction forces of the two supporting rollers on the central long pressure zone pressure unit are symmetrically offset, reducing the flexural deformation of the bending beam of the central long pressure zone pressure unit. The patent does not consider the problem of flexural deformation of the supporting rollers on both sides caused by the opposite pressing forces applied to both sides by the central long pressure zone pressure unit, and the problem of fatigue damage caused by the bearings supporting the rotation of the supporting rollers on both sides under alternating loads. In addition, the supporting rollers on both sides need to be driven by electric motors, and the bearings of the supporting rollers are subjected to the huge shoe pressure applied on one side, resulting in the bearing friction f 轴承The motor consumes a lot of power, so it is very large. In addition, in order to adapt to the flexural deformation of the supporting rollers on both sides, the roller sleeve of the central long nip pressure unit needs to be supported by the boot-shaped plate to produce a large deformation when working, which makes the roller sleeve easy to age and affects its service life.

[0004] For relevant terminology and common knowledge, please refer to the "Pulp and Paper Machinery and Equipment Volume 2" published by China Light Industry Press in 2003, the "Mechanical Engineering Handbook" and "Electrical Engineering Handbook" published by Machinery Industry Press in 1983 or 1997, and the industry standard QB / T 1693-1993 "Terminology of Pulp and Paper Machinery and Equipment", and the British patent GB2218122B "A press section of a machine for the production of a fibrous web, particularly a paper web". Summary of the invention

[0005] The purpose of the present invention is to provide a pressing device for papermaking equipment to solve the technical problems existing in the above-mentioned background technology.

[0006] A pressing device of a papermaking equipment of the present invention comprises:

[0007] A cylindrical support roller driven by an electric motor;

[0008] A first shoe-type press roller applying a first pressure F1 to the support roller, for forming a first wide pressing area N1 for pressing the paper web between the support roller and the first shoe-type press roller;

[0009] A second shoe-type press roller applies a second pressure F2 which is greater than or equal to the first pressure F1 and can offset or partially offset the first pressure F1 to the support roller, so as to form a second wide pressing area N2 for pressing the paper web between the support roller and the second shoe-type press roller;

[0010] A pressing group formed by a vacuum pressing roller and a common pressing roller for squeezing out moisture from a paper web, wherein the pressing group is arranged on a paper web conveying path before the paper web is conveyed to the first wide pressing area N1, so as to remove at least part of the moisture from the paper web before the paper web is conveyed to the first wide pressing area N1;

[0011] A first felt for guiding the paper web through the first wide nip N1 and a third felt for guiding the paper web through the second wide nip N2;

[0012] The first pressure F1 is not less than 500 kN / m, and the second pressure F2 = (1.0-1.5) F1;

[0013] The support roller includes: a load-bearing member located in the cylindrical roller shell cavity of the support roller for supporting the inner wall of the cylindrical roller shell, and the load-bearing member can prevent the roller shell from bending and deformation when the first pressure F1 and the second pressure F2 act on the roller shell.

[0014] Preferably, the support roller drives the first shoe roller and the second shoe roller to rotate by rotation, so that after the paper web is pressed for the first time in the first wide pressing area N1, it enters the second wide pressing area N2 along the outer surface of the cylindrical roller shell of the support roller for the second pressing.

[0015] Preferably, the support roller further comprises: a rotating shaft fixedly connected to the cylindrical roller shell; and a bearing supporting the rotating shaft.

[0016] Preferably, the motor is connected to the rotating shaft of the support roller, and drives the cylindrical roller shell to rotate, so that the paper web passes through the first wide nip N1 and the second wide nip N2 continuously, and the paper web is pressed in two wide nip sections continuously.

[0017] The present invention arranges a first shoe-type pressure roller on one side of the support roller and a second shoe-type pressure roller on the other side, and forms two wide pressure zones with a high squeezing rate effect on the circumferential surface of the support roller to squeeze the paper web. The pressure directions applied by the two shoe-type pressure rollers to the support roller are different. Through reasonable presetting, the pressures on both sides of the support roller can offset each other or mostly offset each other, so that the support roller located in the middle position can avoid pressure deformation, and it does not need to have a built-in complex hydraulic device to adjust and adapt to the deflection change of the support roller, that is, the support roller does not need to use a complex and expensive controllable middle-height roller; at the same time, because the support roller has no flexural deformation or only slight flexural deformation, the roller shell of the support roller and the bearing supporting its rotation avoid bearing the alternating stress caused by large deflection, reducing the risk of cracking and breaking, and improving reliability. The shoe-type pressure roller sleeve adapted to the shape of the roller shell will not produce large-scale local repeated deformation, avoiding fatigue damage and frequent replacement. The pressing device uses only one motor to drive the supporting roller to rotate one circle to achieve two wide-nip pressings, which is equivalent to two independent shoe pressing systems. Moreover, the motor only needs to overcome the sliding friction between the shoe sleeves and the shoe plates on both sides. 靴压 , there is no controllable sliding friction f of the middle and high rollers 背压 , the bearing force of the supporting roller is offset, and the bearing friction force f 轴承 The motor power consumption is small, and the motor power consumption is generally equal to about 50% of the total power of the motor with controllable middle and high rollers, or even less, and the energy saving effect is obvious.

[0018] Preferably, the second shoe-type pressure roller is located on the other side of a plane P passing through the axis of the supporting roller and perpendicular to a line connecting the axes of the first shoe-type pressure roller and the supporting roller, and an angle Q between a line connecting the axes of the second shoe-type pressure roller and the supporting roller and a line connecting the axes of the first shoe-type pressure roller and the supporting roller is not greater than 30 degrees.

[0019] Since the force F2cosQ of the second shoe-type roller on the supporting roller is opposite to the force F1 of the first shoe-type roller on the supporting roller, when the values ​​of F1 and F2 are close and the Q value is not greater than 30 degrees, the resultant force F 合1 and F 合2 The value of can be greatly reduced, and the pressure on the support roller 10 is offset and reduced, so the deflection deformation of the support roller 10 can be reduced. In particular, when the values ​​of F1 and F2 are close and the Q value is close to 0 degrees, F 合1 and F 合2 The value of can be close to zero, and the pressures on the supporting roller 10 are in opposite directions and offset each other. The supporting roller 10 has basically no flexural deformation, and the roller shell of the supporting roller and the bearing supporting its rotation avoid the alternating stress caused by large flexure, reducing the risk of cracking and breaking, and improving reliability. Therefore, the supporting roller 10 does not need to have a built-in complex hydraulic device, that is, there is no need to use a controllable middle and high roller to adjust to the deflection change of the supporting roller 10. The lateral wide pressure zone relative to the boot-type pressure roller can obtain uniform pressure zone conditions, and the forces on both sides of the bearing of the supporting roller offset each other, and its bearing friction force f 轴承 Reduced, the power consumption of the motor is reduced.

[0020] Preferably, the load-bearing member is a plurality of parallel supporting baffles located in the inner cavity of the cylindrical roller shell, and the outer periphery of the supporting baffles abuts against the inner cavity wall of the roller shell to fixedly support the roller shell.

[0021] Since the inner cavity of the roller shell of the present invention is supported by parallel supporting partitions, the bending strength is increased, and the forces on both sides thereof are offset or mostly offset, so the roller shell will not produce large flexural deformation. At the same time, the bearings supporting the rotation of the rotating shafts at both ends are not subject to much pressure and avoid bearing the alternating stress caused by the flexure of the roller shell. The bearings reduce the risk of pressure cracking failure and the reliability is improved.

[0022] Preferably, the pressing device for processing a paper web of the present invention further comprises a pressing group formed by a vacuum pressing roll and a conventional pressing roll, and the paper web is pressed by passing through the press gap between the vacuum pressing roll and the conventional pressing roll before passing through the first wide pressing area N1.

[0023] Before the paper web passes through the first wide pressure zone N1, it is pressed by a pressing group consisting of a front vacuum pressing roller and a common pressing roller. This arrangement is suitable for manufacturing relatively thick paper webs with high moisture content. It can improve the dryness of the paper web after pressing and is conducive to the subsequent double-wide pressure zone pressing to achieve the designed dryness requirements of the paper web.

[0024] Furthermore, the pressing group formed by the vacuum pressing roller and the common pressing roller is located in the lower area of ​​the first wide pressing zone N1 formed between the first shoe-type pressing roller and the support roller. Specifically, the axis connecting line L1 of the vacuum pressing roller and the common pressing roller extends upward and intersects with the axis connecting line L2 of the first shoe-type pressing roller and the support roller at K1, and the intersection K1 is located between the axis of the first shoe-type pressing roller and the axis of the support roller. This design can save space for the entire pressing device.

[0025] Furthermore, the outer diameters of the boot sleeves of the first and second shoe-type rollers are both D1, and the outer diameter of the roller shell of the support roller is D2, so: D2 = (1-1.3) D1. In this way, the space below the first shoe-type roller and the second shoe-type roller is expanded, which is conducive to placing a number of components including a water receiving tray, a guide roller, a vacuum suction roller, a scraper assembly, a vacuum pressing roller, etc.

[0026] Furthermore, the angle Q between the axis connecting the second shoe-type roller and the supporting roller and the axis connecting the first shoe-type roller and the supporting roller is 10 degrees to 15 degrees. This can not only greatly reduce the pressure on the supporting roller, but also increase the space in the lower area between the first shoe-type roller and the second shoe-type roller.

[0027] Preferably, the surface of the roller shell is a smooth surface, which is suitable for directly contacting and adsorbing the paper web and guiding the paper web to rotate and move forward.

[0028] Preferably, the first shoe-type press roller has a first hydraulic cylinder for generating the first pressure; and the second shoe-type press roller has a second hydraulic cylinder for generating the second pressure.

[0029] In summary, the present invention enables the paper web to move continuously to achieve two high-pressure and wide-pressure zone pressing under the driving action of a single motor on the same supporting roller, so the motor consumes little power, which is generally equal to about 50% of the total power of the motor with controllable middle and high rollers, or even less, and the energy-saving effect is obvious.

[0030] In addition, the support roller of the present invention adopts a hollow roller structure with a load-bearing component. Compared with a solid roller structure, the present invention can not only greatly reduce the weight of the support roller but also avoid the pressure deformation of the support roller; the reduction in the weight of the support roller can further reduce the power consumption of the motor.

[0031] In addition, by using a pressing group consisting of a vacuum pressing roll and a common pressing roll to squeeze the moisture of the paper web before pressing the paper web, the surface quality of both sides of the pressed paper web can be significantly improved.

[0032] In addition, the support roller of the present invention works in a balanced state where the first pressure and the second pressure offset each other or mostly offset each other, which can improve the paper web pressing efficiency.

[0033] On the other hand, since the support roller of the present invention has no flexural deformation or only slight flexural deformation, the roller shell of the support roller and the bearing supporting its rotation avoid being subjected to the alternating stress caused by large flexure, reducing the risk of cracking and breaking failure, and improving reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a radial cross-sectional view of a prior art shoe press unit;

[0035] Figure 2 is an axial cross-sectional view of a prior art shoe press unit;

[0036] Figure 3 It is a schematic diagram of the force deformation of the shoe press unit in the prior art;

[0037] Figure 4 It is a schematic diagram of the connection between the controllable middle and high rollers and the motor of the shoe press unit in the prior art;

[0038] Figure 5 is a radial cross-sectional view of a shoe press unit embodiment 1 of the present invention;

[0039] Figure 6 yes Figure 5 AA section view;

[0040] Figure 7 Schematic diagram of the force of the shoe press unit embodiment 1 of the present invention;

[0041] Figure 8 is a radial cross-sectional view of a shoe press unit embodiment 2 of the present invention;

[0042] Fig. 9 Schematic diagram of the force of the shoe press unit embodiment 2 of the present invention;

[0043] Fig.10 1 is a schematic diagram of the assembly of the pressing device embodiment 1 of the present invention;

[0044] Fig.11 Schematic diagram of the assembly of the pressing device of Embodiment 2 of the present invention;

[0045] Fig.12 Schematic diagram of the preferred component layout of the pressing device of the present invention.

[0046] Description of reference numerals:

[0047] Controllable middle and high roller 10', roller shell A 101', crossbeam 102', hydraulic support unit 103', bearing A 104', bearing seat A105', fluid sliding bearing layer 106', boot-type pressure roller 20', roller sleeve 201, bracket 202, hydraulic cylinder 203, boot-shaped plate 204, first motor 5', reducer 51', first coupling 52', gear transmission pair 53'; supporting roller 10, scraper assembly 11, roller shell 101, rotating shaft 102, supporting partition 103, bearing 104, bearing seat 105, first boot-type pressure roller 20, second boot-type pressure roller 30, guide roller 32, water receiving tray 33, motor 5, flange 51, second coupling 52, plane P; forming mesh 1, paper web 2, first blanket 21, first vacuum suction roller 22, second blanket 23, first wide pressure zone N1, second wide pressure zone N2, third blanket 31, fourth blanket 41, second vacuum suction roller 42, drying cylinder 43. DETAILED DESCRIPTION

[0048] As shown in the accompanying drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. In the embodiments of the present invention: the direction of paper web advancement is forward, and the reverse direction is backward; the boot-type pressure roller refers to a pressure roller in the boot-type pressing unit that is provided with a rotatable roller sleeve, a fixed crossbeam, and a hydraulically controlled boot-shaped plate; the supporting roller refers to a pressure roller that bears the load of the hydraulically controlled boot-shaped plate of the boot-type pressure roller and is paired with the boot-type pressure roller to form a wide pressure zone pressing; the wide pressure zone refers to the pressure zone of the wide pressure zone pressing; the part close to the pressure contact transmission area is the top end or top side, and away from the pressure contact transmission area is the bottom end or bottom side. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention. They are described in detail below in conjunction with specific embodiments.

[0049] Common shoe press units in the prior art include Figure 1 and 2 As shown, the shoe press unit is mainly composed of a shoe press roller 20' and a controllable middle and high roller 10', which are generally arranged one above the other, with the shoe press roller 20' being above the controllable middle and high roller 10'. Bearing seats are provided on the transmission side and the operating side of the two rollers, and the bearing seats are respectively fixed by two locking arms (not shown). In normal operation, the locking arms are used to balance the pressure of the two rollers to ensure the stability of the rollers during operation. Usually, the hydraulic oil system of the two rollers of the shoe press unit is the same.

[0050] The shoe-type pressure roller 20' is mainly composed of a roller sleeve 201, a bracket 202, a hydraulic cylinder 203, and a shoe-shaped plate 204. The roller sleeve 201 is made of a flexible material such as polyurethane, which is actually a synthetic tape. The shoe-type pressure roller 20' is a wide-nip pressing roller. When working, the roller sleeve 201 is mainly in a circular path around the bracket 202 and the shoe-shaped plate 204 to overcome the friction between the roller sleeve 201 and the shoe-shaped plate 204.靴压 The shoe-shaped plate 204 has a sliding top surface for the roller sleeve 201 to slide, which is also adapted to the shape of the controllable middle and high roller 10', and when the hydraulic cylinder 203 is ejected, the roller sleeve 201 is pressed against the controllable middle and high roller 10', and the paper web or felt is pressed against the outer periphery of the controllable middle and high roller 10' to achieve squeezing and dehydration. The hydraulic cylinder 203 is fixedly mounted on a non-rotatable bracket 202, and both ends of the bracket 202 are supported by fixed bearing seats.

[0051] The main components of the controllable middle and high roller 10' are composed of a roller shell A101', a crossbeam 102', a hydraulic support unit 103', a bearing A104', and a bearing seat A105'. The bearing seat A105' is fixedly installed on the non-rotatable crossbeam 102'. The roller shell A101' is rotatably supported and installed on the bearing seat A105' through the bearing A104'. The gap between the hydraulic support unit 103' and the roller shell A101' has a fluid sliding bearing layer 106' formed by hydraulic lubricating oil. The connection structure of the controllable middle and high roller 10' and the motor is shown in FIG. Figure 4 As shown, the roller shell A101' is fixed with a gear at one end thereof, and a gear pair 53', a first coupling 52', a reducer 51' and a first motor 5' are provided on both sides of the axis of the roller shell A101'. The first motor drives the controllable middle and high roller 10' to overcome the sliding friction f between the roller shell A101' and the hydraulic support unit 103'. 背压 and the friction force f of the bearing A104' supporting the roller shell 轴承 , driving the roller sleeve 201 of the shoe-type pressure roller 20' to overcome the friction force f between the roller sleeve 201 and the shoe-shaped plate 204 靴压 In other applications, it is also feasible that only one side of the axis of the roller shell A101' is connected to the first motor 5' by the gear pair 53', the first coupling 52', the reducer 51'.

[0052] Since the working pressure exerted by the shoe-shaped plate 204 on the paper web or felt is very large, for example, the average pressure F1' on the 250mm wide shoe-shaped plate can reach a linear pressure of 1050kN / m, which is 8 times the pressing pressure of the conventional roller. The fixed beam of the roller is flexed and deformed under this pressure, and the deformation can reach a large amount of more than ten millimeters. Figure 3As shown. To solve the problem caused by the deformation, the supporting roller adopts a controllable middle-height roller. The controllable middle-height roller is equipped with a hydraulic support unit 103' on the fixed non-rotating crossbeam 102' at the center. The hydraulic support unit 103' and the hydraulic cylinder 203 of the boot-type pressure roller use the same hydraulic oil system to provide an adaptive liquid balance pressure F2' to act on the roller shell A101', which is balanced with the pressure F1' of the boot-type pressure roller. Therefore, the roller shell A101' does not flex and deform, and the rotating roller shell A101' and the bearing A104' supporting its operation are not subjected to much pressure, and are not subjected to alternating stress, are not prone to fatigue damage, and have high reliability. Moreover, since the roller sleeve 201 of the boot-type pressure roller is made of flexible material, the pressure it bears is transmitted to the fixed bracket 202 by the boot-shaped plate 204 that supports it, so the pressure on the bearing (not shown) supporting the roller sleeve 201 is not large, and the risk of failure of the bearing is not great. The flexural deformation of the bracket 202 and the crossbeam 102' can be adjusted by adjusting the load pressure of the hydraulic cylinder 203 and the relative hydraulic support unit 103' to achieve a uniform lateral pressure zone condition and achieve good pressing efficiency. The support roller of the shoe-type pressing unit adopts a controllable middle and high roller, which makes the system complex, difficult to maintain, and high in cost. In addition, the first motor 5' that drives the controllable middle and high roller to rotate needs to overcome the sliding friction f between the roller sleeve 201 and the shoe-shaped plate 204 at the same time. 靴压 and the sliding friction force f between the controllable middle and high roller shell and the hydraulic support unit 背压 and the friction force f of the bearing A104' supporting the roller shell 轴承 , the power consumption is large. Especially for the double shoe press system, the power consumption needs to be doubled. For example, for a double shoe press system with a width of 4800mm and a speed of 1000m / min and equipped with controllable middle and high rollers, the total power of the motor reaches 2500kW.

[0053] See also Figure 5 , Figure 6 , Figure 8 and Fig. 9A pressing device with a double-wide pressing zone for papermaking equipment of the present invention comprises: a cylindrical support roller 10 driven by a motor 5; a first shoe-type pressing roller 20 abutting against one side of the support roller 10 and rotating under the drive of the support roller 10, the first shoe-type pressing roller 20 applies a first pressure F1 to the support roller 10, thereby forming a first wide pressing zone N1 for pressing the paper web 2 between the support roller 10 and the first shoe-type pressing roller 20; a second shoe-type pressing roller 30 abutting against the other side of the support roller 10 and rotating under the drive of the support roller 10, the second shoe-type pressing roller 30 applies a pressure greater than or equal to the first pressure F1 to the support roller 10 and can A second wide pressure zone N2 for pressing the paper web 2 is formed between the supporting roller 20 and the second shoe-type pressing roller 30 to offset or partially offset the first pressure; a pressing group formed by a vacuum pressing roller 24 and a common pressing roller 25 for squeezing out moisture from the paper web 2, the pressing group being arranged on the paper web conveying path before the paper web 2 is conveyed to the first wide pressure zone N1, so as to at least remove part of the moisture from the paper web 2 before the paper web 2 is conveyed to the first wide pressure zone N1; a first felt 21 for guiding the paper web 2 through the first wide pressure zone N1 and a third felt 31 for guiding the paper web 2 through the second wide pressure zone N2.

[0054] In order to improve the dryness of the paper web passing through the double-width pressing device, the first pressure F1 is not less than the linear pressure of 500 kN / m; the second pressure is F2, and the value of F2 should be not less than the value of F1, preferably F2 = (1.0-1.5) F1.

[0055] See also Figure 6 The supporting roller 10 of the present invention includes: a load-bearing component located in the cavity of the cylindrical roller shell 101 of the supporting roller and used to support the inner wall of the cylindrical roller shell 101, and the load-bearing component can prevent the roller shell 101 from bending and deforming when the first pressure F1 and the second pressure F2 act on the roller shell 101.

[0056] The support roller 10 drives the first shoe-type press roller 20 and the second shoe-type press roller 30 to rotate by rotating, so that the paper web 2 enters the second wide press area N2 for the second pressing along the outer surface of the cylindrical roller shell 101 of the support roller 10 after the first pressing in the first wide press area N1. In this way, the pressing efficiency of the paper web can be improved.

[0057] See also Figure 6 The support roller 10 of the present invention further comprises: a rotating shaft 102 fixedly connected to the cylindrical roller shell; and a bearing 104 supporting the rotating shaft 102. The motor 5 is connected to the rotating shaft 102 of the support roller 10, and drives the cylindrical roller shell 101 to rotate, so that the paper web 2 continuously passes through the first wide nip N1 and the second wide nip N2, and the paper web 20 is continuously pressed in two wide nip zones.

[0058] It should be noted that the reason why the support roller of the present invention does not use a solid roller is to reduce the weight of the support roller so as to reduce the power consumption of the motor driving the support roller to rotate. However, the support roller of the paper web pressing device needs to bear a pressure of 1050 kN / m, that is, the paper web pressing device needs to bear a pressure equal to 10 times that of the calender 100 kN / m. For this reason, the present invention adopts a technology of supporting the inner wall of the cylindrical roller shell 101 with a load-bearing member in the cavity of the cylindrical roller shell 101 of the support roller, so as to reduce the weight of the support roller and avoid the flexural deformation of the roller shell 101.

[0059] The pressing device with double-width pressing zones of the papermaking equipment of the present invention is described in detail below with reference to specific embodiments.

[0060] Shoe press unit embodiment 1 of the present invention:

[0061] Shoe press unit embodiment 1 of the present invention is as follows Figure 5 , 6 As shown, the shoe press unit consists of a support roller 10 located in the middle, a first shoe press roller 20 located on one side of the support roller 10 and arranged parallel to the support roller 10 , and a second shoe press roller 30 located on the other side of the support roller 10 .

[0062] Specifically, in the radial projection direction, the second shoe-type roller 30 and the first shoe-type roller 20 are respectively located on both sides of a plane P passing through the axis of the support roller 10 and perpendicular to the axis connecting the first shoe-type roller 20 and the support roller 10, and the angle between the axis connecting the second shoe-type roller 30 and the support roller 10 and the axis connecting the first shoe-type roller 20 and the support roller 10 is Q, and the value of Q is not greater than 30 degrees. Preferably, it is 0 degrees, 10 degrees, 15 degrees, and 30 degrees.

[0063] The structure of the first shoe-type press roller 20 and the second shoe-type press roller 30 is the same as the structure of the shoe-type press roller 20' in the above-mentioned prior art, and will not be repeated here. The first wide pressure zone N1 of the pressing unit is formed in the pressure gap between the first shoe-type press roller 20 and the support roller 10, and the second wide pressure zone N2 is formed in the pressure gap between the second shoe-type press roller 30 and the support roller 10.

[0064] like Figure 6 As shown, the main components of the supporting roller 10 are composed of a roller shell 101, a rotating shaft 102, a supporting partition 103, a bearing 104, and a bearing seat 105. The roller shell 101 is a hollow cylindrical body, and its two ends are fixed to the rotating shaft 102. The rotating shaft 102 is supported and placed on the bearing seat 105 through the bearing 104. A load-bearing member is arranged in the inner cavity of the roller shell 101 to support its inner wall, such as Figure 6As shown, the load-bearing member is a plurality of supporting baffles 103 arranged in parallel at a certain distance axially in the inner cavity of the roller shell 101. The outer periphery of the supporting baffles 103 abuts against the inner cavity wall of the roller shell 101 to fix and support the roller shell 101, and each supporting baffle 103 is fixedly connected to each other as an integral structure. In other embodiments, the load-bearing member may be an I-beam arranged in the inner cavity of the roller shell 101, and the outer periphery of the I-beam fits and abuts against the inner wall of the roller shell 101; the load-bearing member may also be a cylindrical column arranged coaxially with the roller shell 101, and the outer periphery of the column fits and abuts against the inner wall of the roller shell 101. The load-bearing member has various structural forms, as long as it can be fixedly fitted and abutted against the inner wall of the roller shell 101 to increase the bending strength of the roller shell 101. The connection structure between the supporting roller 10 and the motor is shown in FIG. Figure 6 As shown, the rotating shaft 102 is rigidly connected to the motor shaft of the motor 5 through the flange 51, and the motor directly drives the roller shell 101 to overcome the friction force f of the bearing 104 supporting the roller shell. 轴承 , driving the roller sleeves 201 of the first shoe-type roller 20 and the second shoe-type roller 30 to overcome the friction force f between the roller sleeves 201 and the corresponding shoe-shaped plates 204 靴压 It rotates together with the roller shell 101 to smoothly carry the paper web 2 through the double-width pressing nip. In other embodiments, it is also feasible to connect the rotating shaft 102 and the motor shaft of the motor 5 through a speed reducer, especially when the speed of the supporting roller 10 is not high, a larger torque can be obtained.

[0065] The stress of the shoe press unit in this embodiment is as follows Figure 5 , Figure 7 As shown, F1 is the force of the shoe-type press roller 20 on the support roller 10, and F2 is the force of the second shoe-type press roller 30 on the support roller 10. Generally, in order to improve the dryness of the paper web passing through the shoe-type press unit, the first pressure F1 is not less than the linear pressure of 500 kN / m, and the second pressure F2 is not less than the F1 value, preferably F2 = (1.0-1.5) F1. Without considering the deadweight of the support roller, the directions of F1 and F2 are different, and the resultant force F in one direction is 合1 =F1-F2*cosQ, the resultant force in the other direction is F 合2 =F2*sinQ, when the value of F2 is equal to the value of F1 or not greater than 1.5 times the value of F1, and the value of Q is not greater than 30 degrees, F 合1 and F 合2 The values ​​of can be offset to a large extent and reduced, and the pressure on the support roller 10 can be offset and reduced, so the deflection deformation of the support roller 10 can be reduced. Preferably, when the values ​​of F1 and F2 are close and the Q value is close to 0 degrees, F 合1 and F 合2The value of is close to zero, and the pressures on the supporting roller 10 are in opposite directions and offset each other, so the supporting roller 10 has basically no flexural deformation, and the supporting roller 10 does not need to have a built-in complex hydraulic device, that is, there is no need to use a controllable middle and high roller to adjust to the deflection change of the supporting roller 10, and the lateral wide pressure zone relative to the shoe-type pressure roller can obtain uniform pressure zone conditions. In addition, the supporting roller 10 has a simple structure, and the load-bearing component fixedly connected to the roller shell 101 can improve the bending strength of the roller shell. The pressure on the roller shell 101 and the bearing 104 supporting its rotation is reduced because the forces on both sides offset each other, thereby reducing the friction force f of the bearing 104. 轴承 , the power consumption of the motor is reduced. In particular, the alternating stress caused by the deflection of the roller shell is greatly reduced, thereby reducing the risk of cracking or breaking of the roller shell and bearing of the supporting roller, and improving reliability.

[0066] Shoe press unit embodiment 2 of the present invention:

[0067] Shoe press unit example 2 Figure 8 , Fig. 9 As shown, it is a modified design of the shoe press unit embodiment 1. In this embodiment, the angle Q between the line connecting the axis of the second shoe press roller 30 and the axis of the support roller 10 and the line connecting the axis of the first shoe press roller 20 and the axis of the support roller 10 is 0 degrees, that is, the two shoe press rollers are symmetrically arranged on both sides of the plane P. The shoe plates of the two shoe press rollers and the support roller 10 form two symmetrically arranged wide pressing areas, namely the first wide pressing area N1 and the second wide pressing area N2. The connection structure between the support roller 10 and the motor 5 in this embodiment is shown in FIG. Fig. 9 As shown, the rotating shaft 102 of the supporting roller 10 is connected to the motor shaft of the motor 5 through a second coupling 52, preferably a flexible connection, which can compensate for the relative offset of the two shaft axes and reduce vibration. The roller shell 101 is driven by the motor 5 to overcome the friction force f of the bearing 104 supporting the roller shell. 轴承 , driving the roller sleeves 201 of the two shoe-type pressure rollers arranged symmetrically with the supporting roller 10 to overcome the friction force f between the roller sleeves 201 and the shoe-shaped plate 204 靴压 In this way, the roller shell 101 guides the paper web 2 to continuously pass through the first wide nip N1 and the second wide nip N2 every time it rotates, completing two wide nip pressings with high pressing efficiency.

[0068] The force of the shoe press unit of the present invention is as follows Figure 8 , Fig. 9As shown, the pressure on both sides of the support roller 10 is symmetrically offset, which can greatly reduce the pressure deformation. There is no need to build in complex hydraulic devices to adjust and adapt to the deflection change of the support roller 10. The wide pressure zones N1 and N2 on both sides can obtain uniform pressure zone conditions in the transverse direction, and achieve good squeezing effect. The support roller has a simple structure, and the load-bearing component fixed to the roller shell can improve the bending strength of the roller shell. In addition, the pressure on the two sides of the roller shell is offset in opposite directions. Therefore, the roller shell and the bearing 104 supporting its rotation are not subjected to much pressure and will not be subjected to the alternating stress caused by the deflection of the roller shell, which reduces the risk of cracking or breaking, and improves reliability.

[0069] In particular, the shoe press unit of the present invention only needs to use one motor 5 to drive the support roller to rotate, and the motor only needs to overcome the sliding friction force f between the shoe sleeves and the shoe plates of the shoe press rollers on both sides symmetrically arranged with the support roller 10. 靴压 , there is no controllable sliding friction f of the middle and high rollers 背压， Moreover, the bearing force of the supporting roller is balanced, and the bearing friction force f 轴承 The power consumption of the motor is small, and the power consumption of the driving motor of the shoe press unit is generally equal to about 50% of the total power consumption of the driving motor of the double shoe press system with controllable middle and high rollers, or even lower, and the energy consumption performance is greatly improved. For example, the shoe press unit of this embodiment is applied to a press section with a width of 4800mm and a speed of 1000m / min. Only one motor is needed to drive the supporting roller located in the center of the two shoe press rollers. It has been verified by experiments that the motor power of 1000kW can drive the roller shell of the central supporting roller and the boot sleeves of the shoe press rollers on both sides, guide the paper web 2 to continuously pass through the first wide pressing area N1 and the second wide pressing area N2, complete two wide pressing areas, and save 60% of the power consumption of the motor.

[0070] Pressing device embodiment 1:

[0071] The pressing device of this embodiment is mainly composed of the shoe press unit of the present invention. Fig.10 As shown, the first felt 21 enters from below and picks up the paper web 2 from the forming wire 1 through the first vacuum suction roller 22. Subsequently, the first felt 21 and the paper web 2 are fed to the first wide nip N1 formed by the first shoe-type press roller 20 and the support roller 10 along the traveling direction of the paper web, and the paper web 2 is guided through the nip between the first felt 21 and the support roller 10 to be pressed and dehydrated. Then, the still wet paper web 2 can adhere to the surface of the support roller 10 and continue to travel after leaving the first felt 21, and is guided through the second wide nip N2 together with the third felt 31, wherein the paper web is guided through the nip between the support roller 10 and the third felt 31 to be pressed.

[0072] The roller shell 101 of the supporting roller 10 has a smooth surface suitable for direct contact with the paper web 2, for example, a stone roller or a roller with a certain plasticity is adopted.

[0073] After the paper web 2 passes through the second wide pressure zone N2, the second vacuum suction roller 42 transfers the paper web 2 from the third felt 31 or from the roller shell 101 directly to the fourth felt 41 and sends it to the drying cylinder 43 for drying.

[0074] The two wide pressing areas N1 and N2 of this embodiment are formed on the symmetrical sides of the same support roller 10 located in the center, and the pressing dryness is further improved. In addition, the support roller located in the center will not or will reduce bending deformation due to pressure compensation, and the roller shell and bearing of the support roller avoid bearing the alternating stress caused by the bending of the roller shell, reducing the risk of cracking and breaking, and improving reliability. In particular, the pressing device of this embodiment uses only one motor to drive the support roller to rotate. The motor only needs to overcome the sliding friction f between the shoe sleeves and the shoe plates of the shoe-type pressure rollers on both sides arranged symmetrically with the support roller. 靴压 , there is no controllable sliding friction f of the middle and high rollers 背压， Moreover, the bearing force of the supporting roller is balanced, and the bearing friction force f 轴承 The power consumption of the motor is small, so the power consumption of the driving motor of the pressing device is generally equal to about 50% of the power consumption of the driving motor of the double shoe pressing system with controllable middle and high rollers, or even less, and the energy consumption performance is greatly improved. For example, the pressing device of this embodiment with a width of 4800mm and a speed of 1000m / min only needs one motor to drive the supporting roller located in the center of the two shoe-type pressing rollers. It has been verified by experiments that the motor power of 1000kW can drive the roller shell of the supporting roller and the shoe sleeves of the two shoe-type pressing rollers, guide the paper web 2 to continuously pass through the first wide pressing area N1 and the second wide pressing area N2, complete two wide pressing areas, and save 60% of the motor power.

[0075] Pressing device embodiment 2:

[0076] Embodiment 2 is an improved design of embodiment 1, such as Fig.11 As shown, the main difference is that in the upstream area before the paper web 2 and the first felt 21 pass through the first wide pressing area N1, a pressing structure including a second felt 23, a vacuum pressing roller 24 and a common pressing roller 25 is further provided, and the paper web 2, the first felt 21 and the second felt 23 are guided together through the pressing area between the vacuum pressing roller 24 and the common pressing roller 25 for pressing. The other structures are basically the same as those in Example 1 and will not be described in detail here.

[0077] This embodiment has the advantages of the embodiment 1, and before the paper web 2 passes through the first wide nip N1, a pressing group consisting of a vacuum pressing roller 24 and a common pressing roller 25 is added for pressing. This arrangement is suitable for manufacturing relatively thick paper webs with a large water content, and can improve the dryness of the paper web with a high water content after pressing, which is conducive to the subsequent wide nip pressing to achieve the design dryness requirements of the paper web, and can significantly improve the surface quality of both sides of the paper web. The energy-saving effect of this pressing device embodiment is equivalent to that of the pressing device embodiment 1, and will not be repeated here.

[0078] The components of the pressing device of the present invention are preferably arranged as follows Fig.12 As shown, in order to save space for the entire pressing device, the pressing group formed by the vacuum pressing roller 24 and the ordinary pressing roller 25 is preferably placed in the area below the first wide pressing zone N1 formed between the first shoe-type pressing roller 20 and the support roller 10. Specifically, the arrangement allows the axial line L1 of the vacuum pressing roller 24 and the ordinary pressing roller 25 to extend upward and intersect the axial line L2 of the first shoe-type pressing roller 20 and the support roller 10 at K1, and the intersection K1 is located between the axis of the first shoe-type pressing roller 20 and the axis of the support roller 10. In addition, for the double-width nip pressing device provided with the first shoe-type roller 20 and the second shoe-type roller 30, if the outer diameter of the shoe sleeve of the first shoe-type roller 20 and the second shoe-type roller 30 is D1, and the outer diameter of the roller shell 101 of the supporting roller 10 is D2, D2=(1-1.3)D1 is set, so that the space for arranging components in the lower area between the first shoe-type roller 20 and the second shoe-type roller 30 is expanded, which is conducive to arranging components including the water receiving tray 33, the guide roller 32, the vacuum suction roller 42, the scraper assembly 11, the vacuum pressing roller 24, etc. Preferably, the angle Q value of the line connecting the axis of the second shoe-type roller 30 and the axis of the supporting roller 10 and the line connecting the axis of the first shoe-type roller 20 and the axis of the supporting roller 10 is (10-15) degrees, so that the pressure on the supporting roller 10 can be largely offset and reduced, and the space for arranging components in the lower area between the first shoe-type roller 20 and the second shoe-type roller 30 can be increased.

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pressing device of a papermaking equipment, comprising: A cylindrical support roller (10) driven by a motor (5); a first shoe-type pressure roller (20) applying a first pressure F1 to the support roller (10), and used to form a first wide pressure zone N1 between the support roller (10) and the first shoe-type pressure roller (20) for pressing the paper web (2); a second shoe-type pressure roller (30) for applying a second pressure F2 which is greater than or equal to the first pressure F1 and is capable of offsetting or partially offsetting the first pressure F1 to the support roller (10), so as to form a second wide pressure zone N2 for pressing the paper web (2) between the support roller (10) and the second shoe-type pressure roller (30); guiding the paper web (2) through a first felt (21) of the first wide nip N1 and a third felt (31) of the second wide nip N2; The first pressure F1 is not less than 500 kN / m, and the second pressure F2 is 1.0 to 1.5 times of F1; The supporting roller (10) comprises: a load-bearing component located in the cavity of the cylindrical roller shell (101) of the supporting roller and used for supporting the inner wall of the cylindrical roller shell (101); the load-bearing component can prevent the cylindrical roller shell (101) from bending and deforming when the first pressure F1 and the second pressure F2 act on the cylindrical roller shell (101).

2. The pressing device of the papermaking equipment according to claim 1, characterized in that: The support roller (10) drives the first shoe-type pressing roller (20) and the second shoe-type pressing roller (30) to rotate by rotating, so that after the paper web (2) is pressed for the first time in the first wide pressing area N1, it enters the second wide pressing area N2 along the outer surface of the cylindrical roller shell (101) of the support roller (10) for the second pressing.

3. The pressing device of the papermaking equipment according to claim 2, characterized in that: The supporting roller (10) further comprises: a rotating shaft (102) fixedly connected to the cylindrical roller shell; and a bearing (104) supporting the rotating shaft (102).

4. The pressing device of the papermaking equipment according to claim 3, characterized in that: The motor (5) is connected to the rotating shaft (102) of the supporting roller (10), and drives the cylindrical roller shell (101) to rotate, so that the paper web (2) continuously passes through the first wide pressure zone N1 and the second wide pressure zone N2, and the paper web (2) is continuously pressed in two wide pressure zones.

5. The pressing device of the papermaking equipment according to claim 1, characterized in that: The second shoe-type pressure roller (30) is located on a side of a plane P passing through the axis of the supporting roller (10) and perpendicular to the axis connecting the first shoe-type pressure roller (20) and the supporting roller (10) relative to the first shoe-type pressure roller (20), and the angle Q between the axis connecting the second shoe-type pressure roller (30) and the supporting roller (10) and the axis connecting the first shoe-type pressure roller (20) and the supporting roller (10) is not greater than 30 degrees.

6. The pressing device of the papermaking equipment according to claim 1, characterized in that: The load-bearing component comprises a plurality of parallel supporting baffles (103), the outer periphery of the supporting baffles (103) abuts against the inner cavity wall of the cylindrical roller shell to fixedly support the cylindrical roller shell (101).

7. The pressing device of the papermaking equipment according to claim 1, characterized in that: A pressing group for squeezing out moisture from a paper web (2) is formed by a vacuum pressing roller (24) and a common pressing roller (25). The pressing group is arranged on a paper web conveying path before the paper web (2) is conveyed to the first wide pressing area N1, so that at least part of the moisture of the paper web (2) can be removed before the paper web (2) is conveyed to the first wide pressing area N1.

8. The pressing device of the papermaking equipment according to claim 7, characterized in that: The pressing group formed by the vacuum pressing roller (24) and the ordinary pressing roller (25) is located in the lower area of ​​the first wide pressing zone N1 formed between the first shoe-type pressing roller (20) and the support roller (10).

9. The pressing device of the papermaking equipment according to claim 7, characterized in that: The axis line L1 between the vacuum pressing roller (24) and the ordinary pressing roller (25) extends upward and intersects with the axis line L2 between the first shoe-type pressing roller (20) and the supporting roller (10) at K1, and the intersection K1 is located between the axis of the first shoe-type pressing roller (20) and the axis of the supporting roller (10).

10. The pressing device of the papermaking equipment according to claim 1, characterized in that: The outer diameters of the boot sleeves of the first boot-type pressure roller (20) and the second boot-type pressure roller (30) are both D1, and the outer diameter of the cylindrical roller shell (101) of the supporting roller (10) is D2, and D2 is 1 to 1.3 times of D1.

11. The pressing device of the papermaking equipment according to claim 10, characterized in that: The angle Q between the axis connecting the second shoe-type pressure roller (30) and the supporting roller (10) and the axis connecting the first shoe-type pressure roller (20) and the supporting roller (10) is 10 degrees to 15 degrees.

12. The pressing device of a papermaking machine according to any one of claims 1 to 11, characterized in that: The first shoe-type press roller (20) has a first hydraulic cylinder for generating the first pressure; and the second shoe-type press roller (30) has a second hydraulic cylinder for generating the second pressure.

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