Dewatering bar and wire section of paper machine

Abstract

Set the precise position of the surface of the dehydration bar that faces the screen belt. [Solution] The dewatering bar (1) of the paper machine has a body (5) having a longitudinal direction (2) that is aligned laterally with respect to the direction of movement (4) of the screen belt (3), and the body (5) has at least one pressure-resistant sealed chamber (7) that extends in the longitudinal direction (2) of the dewatering bar (1), and the chamber (7) has a connection to a pressure line (8), a wall (11) having a surface (12) facing the screen belt (3) of the paper machine, and side walls (13, 14) connected to the wall (11), the position of the wall (11) of the chamber (7) is variable, and the chamber (7) is equipped with a device (17) for detecting changes in the position of the wall (11) due to changes in pressure inside the chamber (7).

Description

Technical Field

[0001] The present invention relates to a dewatering bar of a paper machine. The dewatering bar has a body having a longitudinal direction arranged transversely to the moving direction of the screen belt. The body has at least one chamber that extends in the longitudinal direction of the dewatering bar and is hermetically sealed against pressure. The chamber has a connection to a pressure line, a wall having a surface facing the screen belt of the paper machine, and side walls connected to the wall. The position of the wall of the chamber is variable.

[0002] The present invention further relates to a wire section of a paper machine having at least one dewatering bar and a screen belt that moves across the dewatering bar transversely to the longitudinal range of the dewatering bar.

Background Art

[0003] A plant for manufacturing a paper strip having a dewatering bar generally has a self - contained circulating screen belt, to which a material mixture for manufacturing the paper strip is supplied at the starting point of the plant. To remove a part of the liquid contained therein from the material mixture, there is a dewatering bar below the screen belt. The dewatering bar extends transversely to the moving direction of the screen belt and is arranged at intervals in the moving direction of the screen belt. A suction box is further arranged below the screen belt in the region of the dewatering bar. The liquid emerging from the material mixture flows or is sucked through the suction box, as is known in principle from European Patent Application Publication No. 4101977.

[0004] When the dewatering bar contacts the underside of the screen belt, it scrapes off the liquid passing through the screen belt. If the surface of the dewatering bar facing the screen belt forms an acute angle with the screen belt, and this angle is open in the direction of the screen belt's movement, the dewatering bar can also be used to exert a suction force on the liquid coming out of the screen belt or material mixture. Since the scraping effect and suction force exerted by the dewatering bar depend on the angle between the surface of the dewatering bar facing the screen belt and the screen belt, it is advantageous if this angle is adjustable.

[0005] U.S. Patent No. 3,497,420 discloses a dewatering bar of the same type, in which the wall of the dewatering bar facing the screen belt of a paper machine can be deformed by a pressure change in the chamber so that the angle between the wall and the screen belt can be changed.

[0006] Austrian Patent No. 341323 discloses a dewatering bar for a paper machine, the side of which faces the screen belt, whose curvature and inclination can be adjusted by an extendable hose. International Publication No. 01 / 36744 describes a holder for a dewatering bar of a paper machine, in which the entire dewatering bar can be adjusted by a pressure chamber. [Overview of the project] [Problems that the invention aims to solve]

[0007] In known devices, the angle or profile of the surface of the dewatering bar facing the screen belt can be adjusted by controlling the pressure in the chamber or hose. However, precisely positioning the surface of the dewatering bar facing the screen belt is difficult due to its interaction with the screen belt. Therefore, providing a solution to this problem is a fundamental objective of the present invention. [Means for solving the problem]

[0008] This objective is achieved by a dewatering bar having the features of claim 1 and a wire section having the features of claim 20. The preferred but non-mandatory features and embodiments of the present invention can be combined in any desired manner, as long as functionally possible, to form the subject matter of the dependent claims.

[0009] In the present invention, the position of the chamber wall, and therefore the surface facing the screen belt of the paper machine, is changed by changing the pressure inside the chamber, as is known from the prior art. However, according to the present invention, the position of the wall facing the screen belt of the paper machine, and therefore the position where the wall surface is located, can be directly and accurately detected by a suitable device, thereby making it possible to more accurately determine the size and shape of the gap between the screen belt and the wall surface. As a further result, this makes it possible to better control the effects of turbulence on the fiber suspension on the screen, which affect the dewatering and fiber orientation of the paper web.

[0010] In the case of the dewatering bar according to the present invention, the position of the entire wall can be changed, and / or the wall itself is deformable, thereby changing the position of the wall opposite the screen belt as well.

[0011] Any suitable measuring device capable of accurately determining the position and / or deformation or movement of a wall having a surface facing the screen belt of a paper machine can be used as the device.

[0012] Here, the device is preferably a tilt sensor or a displacement sensor, because these sensors are easy to install, provide reliable measurement results, and based on these, the inclination of the wall or the surface of the wall facing the screen belt can be directly obtained or derived in a simple manner. In another particularly preferred embodiment of the present invention, the device for detecting the position of the wall is placed in the chamber in the immediate vicinity of the wall or directly on the wall. This allows the device to provide reliable measurement results and furthermore, the device is well protected within the chamber.

[0013] In one embodiment of the present invention, the wall is deformable and has multiple regions having different bending stiffness values. This allows different regions of the deformable wall to be selectively deformed by different amounts when the pressure inside the chamber changes.

[0014] According to the present invention, not only may a region having a low bending stiffness value be placed in a deformable wall adjacent to the screen belt, but a region having a low bending stiffness value may also be placed in the transition region from at least one side wall to that wall. By optionally combining this with walls having regions with different bending stiffness values, this embodiment can further enhance the possibilities for changing the position of the walls.

[0015] For the same reason, the present invention may additionally or alternatively have at least one side wall having a region with a different bending stiffness value.

[0016] A preferred embodiment of the present invention for providing a region having a low bending stiffness value is preferably a groove that opens inward toward the chamber.

[0017] In the present invention, there may be not just one but two or more pressure-sealed chambers arranged in a row extending along the longitudinal direction of the dewatering bar, each chamber having a separate connection to a pressure line. In this embodiment of the present invention, different pressures may be selectively applied to the walls facing the screen belt in different regions, and thus the gap between the walls facing the screen belt and the screen belt may be selectively varied in different regions.

[0018] On the one hand, the chambers may extend straight and be arranged in parallel. However, the chambers may be substantially aligned laterally when viewed longitudinally, but not have a straight course, but rather a zigzag course, for example. In the case of two chambers with a zigzag course, for example, their ends may point toward each other, and as a result, the chambers do not extend parallel to each other.

[0019] In another preferred embodiment of the present invention, each chamber has a positionally variable wall having a surface facing the screen belt of the paper machine, and each chamber may be assigned a device for detecting changes in the position of the wall. As a result, the position of the wall may be selectively changed in different regions, as well as monitored in each region.

[0020] As already explained, the surface facing the screen belt may have a (first) surface segment that forms a first acute angle with respect to the screen belt, and this first acute angle opens in the direction of movement of the screen belt.

[0021] In the case of the dewatering bar according to the present invention, a second surface segment may be positioned behind the first surface segment in the direction of movement of the screen belt, forming a second acute angle between itself and the screen belt that closes in the direction of movement of the screen belt. At least one additional surface segment may be provided between the first surface segment and the second surface segment. In the case of three surface segments, the central surface segment may extend, for example, parallel to the screen belt.

[0022] In this embodiment, a substantially V-shaped surface facing the screen belt may be formed. In particular, by combining two or more pressure-sealed chambers and devices within each chamber for detecting the position of the walls in each chamber, the shape of the surface facing the screen belt can be selectively adjusted and monitored for individual surface segments.

[0023] The wall facing the screen belt or the surface of the wall is subject to high wear, especially in the area that comes into direct mechanical contact with the screen belt. Therefore, in the case of the present invention, the wall of the main body in contact with the screen belt may be made of a wear-resistant material in at least some segments, that is, especially in those areas that are particularly exposed to increased wear. Examples of such materials include polyethylene embedded with wear-resistant particles made of, for example, aluminum oxide, zirconium oxide, silicon nitride, and / or silicon carbide.

[0024] Alternatively or additionally, when viewed in the direction of movement of the screen belt, the dewatering bar may have a strip of wear-resistant material, such as a ceramic strip made of aluminum oxide, zirconium oxide, silicon nitride, and / or silicon carbide, at least at the leading edge and, if appropriate, also at the trailing edge. Therefore, in the case of the dewatering bar according to the present invention, as is known per se, the edges that are most exposed to wear can be made particularly wear-resistant. In another preferred embodiment of the present invention, the strip may be releasably fixed to the main body at the leading edge and, if necessary, also at the trailing edge. Thus, a technically more complex main body can be fitted with a new wear-resistant strip in a simple manner when it is worn.

[0025] Since it may be technically difficult to releasably fix the strip to the main body, in another preferred embodiment of the present invention, the strip may be fixed to the leading edge and, if necessary, also at the trailing edge on a carrier body made of, for example, glass fiber reinforced plastic, which is releasably attached to the main body. In this case, the carrier body, which is firmly connected to the wear-resistant strip, for example, adhesively bonded, can then be releasably connected to the main body in a simple manner.

[0026] In a preferred embodiment of the present invention, the main body of the dewatering bar is made of plastic, for example, polyethylene.

[0027] In another preferred embodiment of the present invention, the main body itself may be composed of at least two parts, namely, a first part for fixing on the carrier bar and a second part having the wall of the chamber facing the screen belt. In this case, the two parts can be manufactured from different materials, and their strengths can be well adapted to different requirements, i.e., the deformability of the wall fixed on the carrier bar on the one hand and related to the screen belt on the other hand.

[0028] Further features and advantages of the present invention will become apparent from the following description of preferred exemplary embodiments of the present invention, which do not limit the scope of protection, with reference to the accompanying drawings.

Brief Description of the Drawings

[0029] [Figure 1] Perspective view of the dehydration bar according to an embodiment of the present invention [Figure 2] Figure showing a cross-section of an integrally designed dehydration bar according to a first embodiment of the present invention [Figure 3] Figure showing a cross-section of a two-piece designed dehydration bar according to a second embodiment of the present invention [Figure 4] Figure showing a cross-section of a three-piece designed dehydration bar according to a third embodiment of the present invention [Figure 5] Figure showing a cross-section of another three-piece designed dehydration bar according to a fourth embodiment of the present invention [Figure 6] Figure showing a cross-section of a four-piece designed dehydration bar according to a fifth embodiment of the present invention [Figure 7] Figure showing a cross-section of a three-piece designed dehydration bar according to a sixth embodiment of the present invention [Figure 8] Figure showing the dehydration bar and the screen belt shown in FIG. 4 in a non-pressurized state [Figure 9] Figure showing the case where the inside of the chamber of the dehydration bar shown in FIG. 8 is in a vacuum state [Figure 10] Figure showing a dehydration bar having two chambers with sensors according to a seventh embodiment of the present invention [Figure 11]A diagram showing a dewatering bar in an unpressurized state according to the eighth embodiment of the present invention. [Figure 12] Figure 11 shows the embodiment in which the chamber is in a vacuum state. [Modes for carrying out the invention]

[0030] The drawings illustrate an embodiment of the dewatering bar according to the present invention, and apart from the features of the present invention as defined in the claims, many components within the scope of the invention may be embodied differently without needing to be specifically mentioned below. In particular, the components and features described in the various embodiments of the present invention can be combined in any desired manner without explicitly describing them in each possible case.

[0031] Figure 1 shows a dewatering bar 1 that can be used, for example, in the wire section of a paper machine. The dewatering bar 1 has a longitudinal direction (arrow 2), and the screen belt 3 shown in Figures 8 and 9 moves along the dewatering bar 1 in a direction laterally to the longitudinal direction 2 in the direction of arrow 4. The dewatering bar 1 has a body 5, on which strips 6 made of a wear-resistant material such as ceramic are arranged.

[0032] Figure 2 shows a first embodiment of the dewatering bar 1 of the present invention having an integrated body 5. The body 5 has a chamber 7, which is pressure-resistant and sealed from the surroundings. Lines 8 and 9 are connected to the chamber 7. One of these two lines 8 and 9 is a pressure line, and the pressure inside the chamber 7 can be changed through this line 8. Preferably, the inside of the chamber 7 is evacuated through the pressure line 8. As the pressure medium, for example, a gas, such as air, or a liquid, such as oil, can be used.

[0033] The main body 5 has an upper part 20 and a bottom part 15. The upper part 20 has a deformable wall 11 having a surface 12 facing the screen belt 3, and two side walls 13, 14. The deformable wall 11, the side walls 13, 14, and the bottom part 15 divide the chamber 7 in the circumferential direction. Furthermore, the chamber 7 is divided by an end wall 16 at the end of the dewatering bar 1. Lines 8, 9 lead to the chamber 7 through one of the two end walls 16. If the dewatering bar has a chamber divided longitudinally 2, lines 8, 9 may lead to the chamber 7 through both end walls 16.

[0034] The integrated design embodiment shown in Figure 2 is made of plastic, such as polyethylene, and wear-resistant particles may be embedded in the deformable wall 11 as needed to enhance the wear resistance of the deformable wall 11.

[0035] A device 17 is positioned on the inner surface 41 of the deformable wall 11 to detect the deformation of the wall 11 and, consequently, the change in the position of the wall 11. This device 17 is, for example, a tilt sensor that detects the inclination of the deformable wall 11 relative to the horizontal. However, instead, the device 17 may be, for example, a measuring device that measures the distance from the bottom surface 18 opposite the bottom 15 to the inner surface 41, or the change in this distance, or other distances.

[0036] The device 17 is connected to line 9, which may be, for example, an electrical line or an optical waveguide. Wireless transmission of measurement results from the device 17 to the controller is also possible.

[0037] Although not shown in the drawings, the deformable wall 11 can have a substantially constant wall thickness and can deform substantially continuously when excessive pressure or vacuum is applied to the chamber 7.

[0038] However, in the present invention, it is preferable that the wall 11 has multiple regions having different bending stiffness values. In the embodiment illustrated in the drawings, the wall 11 has a region 19 having a lower bending stiffness value than adjacent regions 21 and 22. In the embodiment shown in the drawings, the region 19 having a lower bending stiffness value is formed by a groove 23, which has a substantially constant wall thickness and is located between regions 21 and 22 of the wall 11 that have a higher bending stiffness value than the region 19 that has been made more easily bent by the groove 23.

[0039] In addition to or in lieu of the region 19 with low bending stiffness, a further region 24 having lower bending stiffness than the wall 11 can be located in the transition region from the wall 11 to the side wall 14, which in the illustrated embodiment is similarly formed by a groove 25 at the corner between the wall 11 and the side wall 14.

[0040] Additionally or alternatively, a region 26 having a lower bending stiffness value than the wall 11 may be placed in the side wall 13, and this region 26 is similarly formed by a groove 27 in the illustrated embodiment.

[0041] According to the present invention, it is not necessary for all of the regions 19, 24, and 26 having a bending stiffness value lower than that of the wall 11 to be present. Alternatively, none of these regions may be present, or only one or two of the three regions 19, 24, and 26 may be present. Therefore, each of these three regions 19, 24, and 26 may be omitted depending on the requirements. Furthermore, more than three regions may be provided, or one or more regions with low bending stiffness values ​​may be placed in different positions.

[0042] An advantage of embodiments having one, two, or three regions 19, 24, and 26 having lower bending stiffness values ​​than the wall 11 is that when excessive pressure or vacuum is applied inside the chamber 7, the wall 11 deforms only in the regions 19, 24, and 26 with lower overall bending stiffness values, so the device 17 can be attached to a non-deforming portion of the wall 11.

[0043] Theoretically, the present invention also makes it possible to create regions with lower bending stiffness values ​​by using lower-strength materials with lower bending stiffness values ​​in some segments.

[0044] Furthermore, as is known from the prior art, the dewatering bar 1 shown in Figure 1 has a wedge-shaped front edge 28, and the screen belt 3 extends over the dewatering bar 1. Similarly, as is known from the prior art, a substantially T-shaped groove 29 is provided at the bottom 15 for the purpose of attaching the dewatering bar 1 to the carrier bar of the paper machine. However, the specific shape of the front edge 28 and the shape of the groove 29 are not important to the present invention and can be replaced with alternative shapes or omitted entirely, and in the case of the groove 29, it may be replaced with an alternative fixing method.

[0045] Figure 3 shows an alternative embodiment of the dewatering bar 1 according to the present invention, which can be embodied substantially similarly to the dewatering bar 1 of Figure 2 with respect to the main body 5.

[0046] However, the difference between the embodiment in Figure 3 and the embodiment in Figure 2 is that the leading edge 28, which is subjected to the greatest wear, is not formed directly on the main body 5, but rather on a mounting component 31 connected to the main body 5 via a wedge-shaped slot and a key joint 32. The advantage of this embodiment is that the mounting component 31 can be connected to the main body 5 and can be easily removed from the main body 5 again when wear becomes significant, eliminating the need to replace the entire technically complex main body 5 with the device 17, as in the embodiment shown in Figure 2. The mounting component 31 may be manufactured from a material that is more wear-resistant than the main body 5, which needs to have different properties.

[0047] Figure 4 shows yet another three-piece design embodiment of the dewatering bar 1 according to the present invention, where the bottom 15 of the body 5 is a separate component and is releasably or non-releasably connected to the side walls 13, 14 of the body 5. An advantage of this embodiment is that the bottom 15 on the one hand, and the side walls 13, 14 and deformable wall 11 on the other hand, can have different strength characteristics. In particular, the side walls 13, 14 and deformable wall 11 have elastic properties and possibly wear resistance properties that are not required of the bottom 15, which is present only for connection to the carrier bar.

[0048] Figure 5 shows an embodiment of the present invention in which the leading edge 28 is formed by a wear-resistant strip 33 made of, for example, a ceramic material, and this wear-resistant strip 33 is fixed to the carrier body 34, for example, by adhesive bonding. In the illustrated embodiment, the carrier body 34 is T-shaped and is connected to the main body 5 via slots and key joints 32 located in the regions of the side walls 14 and the bottom 15.

[0049] An advantage of this embodiment is that the strip 33, which may be made of ceramic segments that can be manufactured by means known in the prior art, does not need to be directly connected to the main body 5 of the dewatering bar 1, but can be conventionally connected to a carrier body 34 to which a portion is connected 5.

[0050] In the embodiment shown in Figure 6, the embodiments of Figures 3 to 5 are combined. Specifically, a main body 5 having a deformable wall 11 and separate bottoms 15 and side walls 13 and 14 is connected to a carrier body 34 by slots and key joints 32 on the side wall 14, and a wear-resistant strip 33 is again connected to the carrier body 34.

[0051] Figure 7 shows an embodiment of the dewatering bar 1 according to the present invention, similar to the embodiment shown in Figure 5. However, a screw joint 35 is provided instead of a slot and key joint 32 to connect the carrier body 34 to the main body 5.

[0052] The function of the deformable wall 11 according to the present invention, which is linked to the changing pressure inside the chamber 7, can be seen in Figures 8 and 9.

[0053] As the screen belt 3, on which the material mixture 36 is located, moves along the dewatering bar 1 in the direction of arrow 4, and its lower surface comes to rest on the dewatering bar 1, the liquid 37 that has passed through the screen belt 3 is scraped off by the leading edge 28.

[0054] If ambient pressure or a slight excess pressure is dominant within the chamber 7, the surface 12 facing the screen belt 3 becomes linear or planar in the illustrated embodiment, for example, as shown in Figure 8. The sensor 17 sends a signal to the controller corresponding to the state of the surface 12.

[0055] However, when a vacuum is created in the chamber 7 via line 8, the deformable wall 11 is pulled inward by the vacuum, as shown in Figure 9. The wall 11 twists somewhat in the central region 19, which has a low bending stiffness, and the transition region 24 to the side wall 14, which also has a low bending stiffness, deforms somewhat. The region 26 of the other side wall 13, which also has a low bending stiffness, deforms similarly, but to a smaller degree. Of course, the degree of deformation in each region 19, 24, and 26 depends on the degree of deterioration and also on the specific arrangement of each region on the main body 5.

[0056] Between each of the regions 19, 24, and 26 having low bending stiffness values, there are regions 21 and 22 having relatively high bending stiffness values. Therefore, these regions 21 and 22 do not deform and form surface segments 38 and 39 that remain substantially horizontal. These surface segments 38 and 39 form an acute angle with the screen belt 3, and the angle α between the first surface segment 38 and the screen belt 3 is open in the direction of movement 4 of the screen belt 3, resulting in an attractive force acting on the liquid coming out of the screen belt 3 and the material mixture 36. On the other hand, the angle β between the second surface segment 39 and the screen belt 3 is formed in the direction of movement 4 of the screen belt 3, resulting in pressure acting again on the liquid coming out of the screen belt 3 and the material mixture 36. By selectively setting angles α and β, turbulence can be generated in the fiber suspension on the screen belt 3, influencing fiber orientation and thereby influencing the formation of the material mixture 36. Because not only the pressure inside the chamber 7 but also the screen belt 3 on which the material mixture 36 is placed exerts force on the deformable wall 11, accurate measurement of the shape and position of the surface 12 having surface segments 38 and 39 is essential. By directly detecting the position or deformation of the wall 11 with the device 17, angles α and β can always be accurately adjusted even if conditions change during operation.

[0057] The angles α and β can be set using the vacuum level in the chamber 7, and the ratio of these angles is influenced by the geometric shape of the body, particularly the selection and arrangement of regions 19, 24, and 26 having low bending stiffness values.

[0058] In the illustrated embodiment, angle α is half of angle β, for example, because region 19, which has a low bending stiffness value, is located off-center from the wall 11. However, regions 19, 24, and 26, which have low bending stiffness values, can be arranged in appropriately different ways or selectively omitted, so other angle ratios may, of course, be used depending on the desired result.

[0059] The maximum possible values ​​for angles α and β may be, for example, 0° to 1°, 2°, 3°, 4°, 5°, 6° or greater.

[0060] Figure 10 shows an embodiment of the present invention comprising two adjacent chambers 7, which can be subjected to pressure (excess pressure or vacuum) independently of each other. Each of the two chambers 7 is provided with a device 17 for detecting the deformation of the wall 11 due to changes in pressure within the chamber 7, and consequently for detecting changes in the position of the wall 11. This embodiment of the present invention also demonstrates that the surface 12 facing the screen belt 3 can be corrugated, thereby making it possible to generate further turbulence in the fiber suspension.

[0061] Figures 11 and 12 show embodiments of the present invention in which the wall 11 itself is substantially indeformable. To allow the position of the wall 11 to be changed, a region with a low bending stiffness value is provided in the transition region 24 of the side wall 14. Furthermore, regions 26, 42, and 43 with a lower bending stiffness value than the wall 11 are located in the region of the other side wall 13. The regions with low bending stiffness values ​​26, 42, and 43 have grooves 44 and 45 in the end regions of the wall 13 and a groove 27 in the central region of the wall 13. When the chamber 7 is unpressurized (at atmospheric pressure), if the wall 13 has the straight shape shown in Figure 11, the wall 11 is also straight, and its surface 12 is parallel to the screen belt 3. In contrast, when a vacuum is present in the chamber 7, the side wall 13 bends inward, and as a result, the deformable wall 11 can swing like a joint around the region with low bending stiffness value 24, tilting downward toward the side wall 13, and the surface 12 of the wall 11 forms an angle α>0° with the screen belt.

[0062] Although not shown in the drawings, in another embodiment of the present invention, the region 24 having a low bending stiffness value may be located in another position, may be embodied in another way, or may be omitted entirely, provided that the wall 11 has sufficient elasticity, i.e., flexibility, to allow for a desired change in position within the region of the right-hand wall 13.

[0063] The shape of the dewatering bar 1 shown in Figure 12 can also represent the state when the chamber 7 is not pressurized, and it is obvious (as with all other embodiments shown) that when the chamber 7 is pressurized, the dewatering bar 1 can take the shape shown in Figure 11. Similarly, the dewatering bar 1 can take an intermediate shape between the shapes shown in Figure 11 and Figure 12 when not pressurized, take the shape shown in Figure 11 under excessive pressure, and take the shape shown in Figure 12 under vacuum. [Explanation of Symbols]

[0064] 1. Dehydration bar 2. Longitudinal direction, arrow 3 Screen belt 4. Direction of movement, arrow 5 Main unit 6 strips 7 Chambers 8 lines, pressure lines 9 lines 11 Walls, deformable walls 12 Surface 13 Walls, side walls 14 Side wall 15 Bottom 16 End wall 17. Equipment, controller 18. Base 19 Regions with low bending stiffness 20 Top 21 Regions with high bending stiffness 22 Regions with high bending stiffness 23 Groove 24 Regions with low bending stiffness values 25 groove 26 Regions with low bending stiffness 27 Groove 28 Leading edge 29 Groove 30 Trailing edge 31. Installed parts 32 slots and key joints 33 Strip 34 Carrier Body 35 Screw joint 36 Material mixture 37 liquid 38 Surface segments 39 Surface segments 41 Inner self 42 Regions with low bending stiffness values 43 Regions with low bending stiffness 44 Groove 45 Groove

Claims

1. Dewatering bar (1) of a paper machine, The dewatering bar (1) has a main body (5) having a longitudinal direction (2) that is aligned laterally with respect to the direction of movement (4) of the screen belt (3), The main body (5) has at least one pressure-resistant, sealed chamber (7) extending in the longitudinal direction (2) of the dewatering bar (1), The chamber (7) has a connection to the pressure line (8), a wall (11) having a surface (12) facing the screen belt (3) of the paper machine, and side walls (13, 14) connected to the wall (11). The position of the wall (11) of the chamber (7) is variable. The chamber (7) is equipped with a device (17) for detecting changes in the position of the wall (11) due to changes in pressure within the chamber (7). Dehydration bar.

2. The wall (11) is deformable. The dehydration bar according to claim 1.

3. The device (17) is a sensor, particularly a tilt sensor or a displacement sensor. The dehydration bar according to claim 1 or 2.

4. The device (17) for detecting the position of the wall (11) is located inside the chamber (7). A dehydration bar according to any one of claims 1 to 3.

5. The wall (11) is deformable and has multiple regions (19, 21, 22) having different bending stiffness values. A dehydration bar according to any one of claims 2 to 4.

6. A region (19) having a lower bending stiffness value than adjacent regions (21, 22) of the deformable wall (11) extends along the longitudinal direction (2) of the dewatering bar (1) or diagonally with respect to the longitudinal direction (2) of the dewatering bar (1). The dehydration bar according to claim 5.

7. The region (24) has a lower bending stiffness value than the side walls (13, 14) and the wall (11), and the region (24) adjacent to the side walls (13, 14) and the wall (11) is located in at least one transition region from the side wall (13, 14) to the wall (11). A dehydration bar according to any one of claims 1 to 6.

8. At least one of the side walls (13) has regions (26, 42) having different bending stiffness values. A dehydration bar according to any one of claims 1 to 7.

9. Regions (19, 24, 26, 42, 43) having a lower bending stiffness value than the wall preferably have grooves (23, 25, 27, 44, 45) that open inward toward the chamber (7). A dehydration bar according to any one of claims 4 to 8.

10. There are two or more pressure-sealed chambers (7) arranged in a row extending along the longitudinal direction (2) of the dewatering bar (1), each of the chambers (7) having a separate connection to a pressure line (8), A dehydration bar according to any one of claims 1 to 9.

11. Each of the chambers (7) has a wall (11) whose position is variable and has a surface (12) facing the screen belt (3) of the paper machine. Each of the chambers (7) is assigned a device (17) for detecting changes in the position of the wall (11). The dehydration bar according to claim 10.

12. The surface (12) facing the screen belt (3) has a first surface segment (38) that forms a first acute angle (α) with the screen belt (3), The first acute angle opens in the direction of movement (4) of the screen belt (3). A dehydration bar according to any one of claims 1 to 11.

13. A second surface segment (39) that forms a second acute angle with respect to the screen belt (3) in the direction of movement (4) of the screen belt (3) is positioned behind the first surface segment (38) in the direction of movement (4) of the screen belt (3), and at least one further surface segment extending parallel to the screen belt (3) is positioned between the first surface segment (38) and the second surface segment (39), for example. The dehydration bar according to claim 12.

14. The wall (11) of the main body (5) that is in contact with the screen belt (3) is made of a wear-resistant material in at least some segments. A dehydration bar according to any one of claims 1 to 13.

15. When viewed in the direction of movement (4) of the screen belt (3), at least the leading edge (28), and preferably the trailing edge (30), has a strip (6) of wear-resistant material, such as ceramic. A dehydration bar according to any one of claims 1 to 14.

16. The strip (6) is releasably fixed to the main body (5) at its leading edge (28) and, if necessary, its trailing edge (30). The dehydration bar according to claim 15.

17. The strip (6) is fixed to the front edge (28) and optionally the rear edge (30) on a carrier body (34), for example, made of glass fiber reinforced plastic, which is removably arranged on the main body (5). The dehydration bar according to claim 15 or 16.

18. The main body (5) is made of plastic, for example, polyethylene. A dehydration bar according to any one of claims 1 to 17.

19. The main body (5) is composed of at least two parts: a bottom (15) for fixing onto the carrier bar and an upper part (20) having the wall (11) of the chamber (7). A dehydration bar according to any one of claims 1 to 18.

20. The device comprises at least one dewatering bar (1) as described in any one of claims 1 to 19, and a screen belt (3) that moves laterally on the dewatering bar (1) with respect to the longitudinal direction (2) of the dewatering bar, The wire section of a paper machine.

Images