Drainage strip of a paper machine

Abstract

A dewatering bar (1) of a paper machine has a base body (5) with a longitudinal direction oriented transversely to the direction of movement (4) of a wire belt (3). The base body (5) has at least one pressure-tight closed chamber (7) extending in the longitudinal direction (2) of the dewatering bar (1), wherein the chamber (7) has a connection to a pressure line (8), a wall (11) with a surface (12) facing the wire 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 a device (17) for detecting the change in position of the wall (11) due to changes in pressure is arranged in the chamber (7).

Description

[0001] The present invention relates to a drainage bar of a paper machine, wherein the drainage bar has a base body with a longitudinal direction oriented transversely to the direction of movement of a wire belt, wherein the base body has at least one pressure-tight closed chamber extending in the longitudinal direction of the drainage bar, wherein the chamber has a connection to a pressure line, a wall with a surface facing the wire belt of the paper machine and side walls connected to the wall, and wherein the position of the wall of the chamber is changeable.

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

[0003] Systems for producing paper tape with dewatering bars typically have a closed, circulating wire belt onto which a mixture of materials for producing the paper tape is applied at the beginning of the system. To remove some of the liquid contained in the mixture, dewatering bars are located below the wire belt. These bars extend transversely to the direction of movement of the wire belt and are spaced apart from each other in the direction of movement. Furthermore, suction boxes are arranged in the area of ​​the dewatering bars below the wire belt. Liquid escaping from the mixture flows through these boxes or is extracted, as is generally known from EP 4 101 977 A1.

[0004] When the drainage strips are in contact with the underside of the screen belt, they scrape off the liquid that has passed through it. Furthermore, if the surface of the drainage strips facing the screen belt forms an acute angle with the belt, opening in the direction of the belt's movement, a suction force can be exerted on the screen belt or on the liquid that has passed through the material mixture. Since the scraping effect and the suction force exerted by the drainage strips depend on the angle between the surface of the drainage strip facing the screen belt and the belt itself, it is advantageous if this angle is adjustable.

[0005] US Patent 3,497,420 A discloses a generic drainage bar in which the wall facing the wire belt of the paper machine is deformable by pressure changes in the chamber in order to change the angle between the wall and the wire belt.

[0006] From AT 341 323 B, a dewatering bar for paper machines is known, the curvature and inclination of which on the side facing the wire belt can be adjusted by means of expandable hoses. WO 01 / 36744 A1 describes a bracket for a paper machine dewatering bar, with which the entire dewatering bar can be adjusted by means of a pressurizable chamber.

[0007] While known devices allow for adjustment of the angle or course of the side of the drainage bar facing the screen belt by controlling the pressure in the chamber or the hoses, the exact position of the surface of the drainage bar facing the screen belt is difficult to set due to the interaction with the screen belt. The invention therefore aims to remedy this problem.

[0008] This problem is solved with a drainage strip having the features of claim 1 and with a sieve section having the features of claim 19.

[0009] Preferred, but not essential, features and embodiments of the invention, which can be combined arbitrarily as far as functionally possible, are the subject of the dependent claims.

[0010] In the invention, the position of the chamber wall, and thus the surface facing the paper machine's wire belt, is changed by altering the pressure in the chamber, as is known from the prior art. However, according to the invention, the position of the wall, and thus the surface facing the paper machine's wire belt, is directly and precisely determined by a suitable device, which also allows for a more precise determination of the size and shape of the gap between the wire belt and the surface. This subsequently enables better control of the paper web dewatering and influence on the turbulence in the fiber suspension on the wire, which affects fiber orientation.

[0011] In the drainage strip according to the invention, the position of the wall as a whole can be changed and / or the wall itself is deformable, which also changes the position of the wall in relation to the sieve strip.

[0012] Any suitable measuring device can be used that allows the position and / or deformation or movement of the wall with respect to the surface facing the wire belt of the paper machine to be determined exactly.

[0013] It is preferred if the device is a tilt sensor or a displacement sensor, because these sensors are easy to install and provide reliable measurement results from which the inclination of the wall or the surface facing the screen belt can either be directly determined or easily derived.

[0014] In a further, particularly preferred embodiment of the invention, the device for detecting the position of the wall is arranged in the chamber because it can be placed there in the immediate vicinity of or directly on the wall, thus providing reliable measurement results and is also well protected in the chamber.

[0015] In one embodiment of the invention, the wall is deformable and has areas with different bending stiffnesses. This makes it possible to selectively deform different areas of the deformable wall to varying degrees when the pressure in the chamber is changed.

[0016] According to the invention, it is not only possible to arrange a region of lower bending stiffness in the deformable wall adjacent to the screen belt, but also in a transition region between at least one side wall and this wall. This embodiment, optionally in conjunction with a wall that itself has regions with different bending stiffnesses, can further improve the possibilities for changing the position of the wall.

[0017] For the same reason, it is also possible in the invention, either additionally or alternatively, that at least one side wall has areas with different bending stiffnesses.

[0018] A preferred method in the invention for creating an area with lower bending stiffness consists of a groove, preferably open inwards towards the chamber.

[0019] The invention provides for the possibility of having not just one, but two or more pressure-tight sealed chambers extending longitudinally along the drainage strip and arranged side by side, with each chamber having, and preferably having, a separate connection to a pressure line. This embodiment of the invention makes it possible to selectively apply different pressures to the wall facing the filter belt in different areas, thereby selectively altering the gap between the wall surface facing the filter belt and the filter belt in different areas.

[0020] The chambers can be straight and arranged parallel to each other. However, it is also possible that the chambers, while essentially adjacent to each other lengthwise, do not follow a straight path, but rather a zigzag pattern. In the case of two chambers with a zigzag pattern, for example, the points might face each other, meaning the chambers are not parallel.

[0021] In a further preferred embodiment of the invention, if each chamber has a wall whose position can be changed and whose surface faces the wire belt of the paper machine, each chamber can be assigned a device for detecting the change in the wall's position. This makes it possible not only to selectively change the position of the wall in different areas, but also to specifically monitor its position in the respective areas.

[0022] As already explained, the surface facing the sieve belt can have a (first) surface section that encloses a first acute angle with the sieve belt, opening in the direction of movement of the sieve belt.

[0023] Furthermore, in the drainage strip according to the invention, it is additionally possible that, in the direction of movement of the screen belt, a second surface section is arranged after the first surface section, which forms a second acute angle with the screen belt, closing in the direction of movement of the screen belt. At least one further surface section can be located between these two. With three surface sections, for example, the middle surface section can run parallel to the screen.

[0024] With this embodiment, it is possible to create an essentially V-shaped surface facing the screen belt. Particularly in conjunction with two or more pressure-tight sealed chambers and a device for detecting the wall position in each chamber, the geometry of the surface facing the screen belt can be precisely adjusted and monitored in the individual surface sections.

[0025] The wall or surface facing the screen belt is subject to high wear, particularly in those areas where there is direct mechanical contact with the screen belt. Therefore, the invention allows the wall of the base body in contact with the screen belt to be made, at least partially, i.e., especially in those areas subject to increased wear, from a wear-resistant material. Such a material could, for example, be polyethylene in which wear-resistant particles, such as aluminum oxide, zirconium oxide, silicon nitride, and / or silicon carbide, are embedded. Other materials known from the prior art are, of course, also possible.

[0026] Alternatively or additionally, the drainage strip can have a strip made of wear-resistant material, for example ceramic, such as aluminum oxide, zirconium oxide, silicon nitride, and / or silicon carbide, arranged on at least one front edge, and optionally also on one rear edge, as seen in the direction of movement of the screen belt. Thus, in the drainage strip according to the invention, the edges most exposed to wear can be made particularly wear-resistant – as is known per se.

[0027] In a further preferred embodiment of the invention, the strip can be detachably attached to the base body at the front and, optionally, the rear edge. This allows the technically more complex base body to be easily fitted with new wear edges when these become worn.

[0028] Since it can sometimes be technically difficult to detach the strips to the base body, in a further preferred embodiment of the invention the strips can be attached at the front and, if applicable, rear edges to a support body, for example made of glass fiber reinforced plastic, which is detachably mounted to the base body. The support bodies, which are firmly connected to the wear-resistant strips, e.g., by bonding, can be prepared and then easily detachably connected to the base body.

[0029] In a preferred embodiment of the invention, the base body of the drainage strip is made of plastic, for example polyethylene.

[0030] In a further embodiment of the invention, the base body itself can consist of at least two parts: a first part for attachment to a support rail, and a second part comprising the wall of the chamber facing the screen belt. The two parts can be made of different materials whose strength can be well adapted to the different requirements – on the one hand, attachment to a support rail, and on the other hand, the deformability of the wall associated with the screen belt.

[0031] Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, which do not limit the scope of protection, with reference to the accompanying drawings. These show: Fig. 1 an embodiment of a drainage strip according to the invention in a perspective view, Fig. 2 in section a first embodiment of the drainage strip according to the invention in a one-piece design, Fig. 3 in section a second embodiment of the drainage strip according to the invention in a two-piece design, Fig. 4 in section a third embodiment of the drainage strip according to the invention in a three-piece design, Fig. 5 in section a fourth embodiment of the drainage strip according to the invention in another three-piece design, Fig. 6 in section a fifth embodiment of the drainage strip according to the invention in a four-piece design, Fig. 7 in section a sixth embodiment of the drainage strip according to the invention in a three-piece design, Fig. 8 the drainage strip according to Fig. 4 In the unpressurized state, in conjunction with a filter belt, Fig. 9, the drainage strip as shown in Fig. 9, however, with a negative pressure in the chamber of the strip, Fig. 10 a seventh embodiment of the drainage strip according to the invention with two chambers with sensors, Fig. 11 an eighth embodiment of the drainage strip according to the invention in the unpressurized state, and Fig. 12 the embodiment of Fig. 11 in the state where there is negative pressure in the chamber.

[0032] The drawings illustrate embodiments of drainage strips according to the invention, which are, however, only exemplary and, apart from the features of the invention as defined in the claims, can also be designed differently with respect to many components within the scope of the present invention, without this requiring special mention below. In particular, the components and features described in the various embodiments of the invention can be combined with one another as desired, even without this being expressly mentioned in every possible case.

[0033] In Fig. 1 Figure 1 shows a dewatering bar, such as can be used for the wire section of a paper machine. The dewatering bar 1 has a longitudinal direction (arrow 2), with a [missing element] in the Fig. 8 and 9The illustrated sieve belt 3 is moved in the direction of arrow 4, transverse to the longitudinal direction 2, over the drainage strip 1. The drainage strip 1 has a base body 5 on which a strip 6 made of a wear-resistant material, such as ceramic, is arranged.

[0034] In Fig. 2 Figure 1 shows a first embodiment of a drainage strip 1 according to the invention, comprising a one-piece base body 5. The base body 5 has a chamber 7 that is pressure-tight from the environment. Lines 8 and 9 are connected to the chamber 7. One of these two lines 8 and 9 is a pressure line through which the pressure in the chamber 7 can be changed. Preferably, a negative pressure is generated in the chamber 7 via the pressure line 8. A gas, e.g., air, or a liquid, e.g., oil, can be used as the pressure medium.

[0035] The base body 5 has an upper part 20 and a lower part 15. The upper part 20 has a deformable wall 11 with a surface 12 facing the sieve belt 3 and two side walls 13 and 14. The deformable wall 11, the side walls 13 and 14, and the lower part 15 define the chamber 7 circumferentially. The chamber 7 is also bounded at the ends of the drainage strip 1 by end walls 16. The pipes 8 and 9 extend through one of the two end walls 16 into the chamber 7. If the drainage strip has two separate chambers in the longitudinal direction, the pipes 8 and 9 can also extend through both end walls 16 into the chambers 7.

[0036] The in Fig. 2 The illustrated one-piece embodiment consists of plastic, for example polyethylene, into which wear-resistant particles can be embedded in the deformable wall 11 if required, in order to increase the wear resistance of the deformable wall 11.

[0037] A device 17 for detecting the deformation and thus the change in position of the wall 11 is arranged on the inner surface 41 of the deformable wall 11. This device 17 is, for example, an inclination sensor that detects the inclination of the deformable wall 11 relative to the horizontal. Alternatively, the device 17 could also be, for example, a measuring device that measures the distance to the opposite base surface 18 of the lower part 15 or a change in this or any other distance.

[0038] Device 17 is connected to line 9, which can be, for example, an electrical line or a fiber optic cable. Wireless transmission of the measurement results from device 17 to a controller is, of course, also possible.

[0039] In an embodiment not shown in the drawings, the deformable wall 11 can have a substantially constant wall thickness and deform substantially continuously when an overpressure or underpressure is applied in the chamber 7.

[0040] However, it is preferred in the invention if the wall 11 has regions with different bending stiffness. In the embodiments shown in the drawings, the wall 11 has a region 19 which has a lower bending stiffness compared to the adjoining or adjacent regions 21, 22. In the embodiments shown in the drawings, the region 19 with lower bending stiffness is formed by a groove 23 located between the regions 21, 22 of the wall 11, which have a substantially constant wall thickness and a higher bending stiffness than the region 19 weakened by the groove 23.

[0041] In addition or alternatively to the area 19 with lower bending stiffness in the wall 11, a further area 24 with lower bending stiffness can be arranged in the transition area of ​​the wall 11 to the side wall 14, which in the illustrated embodiment is also formed by a groove 25 in the corner between the wall 11 and the side wall 14.

[0042] Additionally or alternatively, a further area 26 with lower bending stiffness can also be arranged in a side wall 13, which in the illustrated embodiment is also formed by a groove 27.

[0043] According to the invention, not all areas 19, 24, and 26 with lower bending stiffness need to be present. It is also possible that none of these areas are present, or that only one or two of the three areas 19, 24, and 26 are present. Each of these three areas 19, 24, and 26 can therefore be omitted according to the specific requirements. More than three areas can also be provided, or one or more areas with lower bending stiffness can be arranged at other locations.

[0044] The advantage of the embodiment with one, two or three areas 19, 24 and 26 with lower bending stiffness is that the device 17 can be attached to a part of the wall 11 that does not deform, i.e., does not deform, because the wall 11 deforms only in the area(s) 19, 24 and 26 with lower bending stiffness when an overpressure or underpressure is applied in the chamber 7.

[0045] Theoretically, it would also be possible with the invention to create areas with lower bending stiffness by using materials with lower strength in certain sections, which have lower bending stiffness.

[0046] The in Fig. 1 The illustrated drainage strip 1, as is known from the prior art, has a wedge-shaped leading edge 28 onto which the wire belt 3 runs. For mounting the drainage strip 1 to a support rail of the paper machine, an approximately T-shaped groove 29 is provided on the lower part 15, as is also known from the prior art. However, the specific shape of the leading edge 28 and the groove 29 are not important for the present invention and can be replaced by alternative geometries or omitted entirely, and, as far as the groove 29 is concerned, replaced by alternative fastening methods.

[0047] In Fig. 3 An alternative embodiment of a drainage strip 1 according to the invention is shown, which, insofar as the base body 5 is concerned, is essentially the same as the drainage strip 1 of Fig. 2 can be executed.

[0048] The embodiment of Fig. 3 differs from the embodiment of Fig. 2 However, this is achieved by the fact that the leading edge 28, which is subject to the greatest wear, is not directly formed on the base body 5, but on a wear part 31, which is connected to the base body 5 via a wedge-shaped tongue-and-groove connection 32. The advantage of this embodiment is that the wear part 31 can be easily connected to and detached from the base body 5 when wear becomes too great, unlike in the embodiment of Fig. 2The technically more complex base body 5 with the device 17 must be completely replaced. The wear part 31 can also be made of a different and, in particular, more wear-resistant material than the base body 5, which must have different properties.

[0049] In Fig. 4A further, three-part embodiment of a drainage strip 1 according to the invention is shown, in which the lower part 15 of the base body 5 is a separate part that is detachably or permanently connected to the side walls 13 and 14 of the base body 5. The advantage of this embodiment is that the lower part 15, on the one hand, and the side walls 13, 14 and the deformable wall 11, on the other hand, can, should, or must have different strength properties. In particular, the side walls 13, 14 and the deformable wall 11 should have elastic and, if necessary, wear-resistant properties, which are not required for the lower part 15, which is only present for connection to a support strip.

[0050] In Fig. 5Figure 1 shows an embodiment of the invention in which the front edge 28 is formed by a wear-resistant strip 33 made of, for example, ceramic material, which is attached, for example, by gluing, to a support body 34.

[0051] The support body 34 is connected to the base body 5 via a tongue-and-groove connection 32, which in the illustrated embodiment is T-shaped and is located in the area of ​​the side wall 14 or the lower part 15.

[0052] The advantage of this embodiment is that the strip 33, which can also consist of ceramic segments, for example, can be manufactured in a manner known from the prior art, because it does not have to be directly connected to the base body 5 of the drainage strip 1, but can be connected in a conventional manner to the support body 34, which in turn is connected to the base body 5.

[0053] In the embodiment of Fig. 6the embodiments of Figs. 3 to 5 combined with each other. That is, a base body 5 with a deformable wall 11 and side walls 13, 14 with a separate lower part 15 is connected to a support body 34 via a tongue and groove connection 32 on the side wall 14, wherein the wear-resistant strip 33 is in turn connected to the support body 34.

[0054] In Fig. 7 An embodiment of a drainage strip 1 according to the invention is shown, which corresponds to the embodiment of Fig. 5 similar. However, instead of a tongue-and-groove connection, a screw connection 35 is provided for connecting the support body 34 to the base body 5.

[0055] From the Fig. 8 and 9 The function of the deformable wall 11 according to the invention in conjunction with a pressure change in the chamber 7 is evident.

[0056] If the sieve belt 3 with the substance mixture 36 on it moves in the direction of the arrow 4 over the drainage bar 1 and its underside rests against the drainage bar 1, liquid 37 that has passed through the sieve belt 3 is wiped off by the front edge 28.

[0057] If, for example, ambient pressure or slight overpressure prevails in chamber 7, the surface 12 facing the sieve belt 3 can be straight or flat in the illustrated embodiment, as shown in Fig. 8 As shown. Sensor 17 will send a corresponding signal to the controller.

[0058] However, if a vacuum is created in chamber 7 via line 8, the deformable wall 11 is drawn inwards into chamber 7 by the vacuum, as shown in Fig. 9The diagram shows that wall 11, with its lower bending stiffness, buckles slightly in the central region 19, and the transition region 24 to the side wall 14, which also has lower bending stiffness, deforms slightly as well. Region 26, with its lower bending stiffness in the other side wall 13, also deforms, but to a lesser extent. The degree of deformation in the respective regions 19, 24, and 26 naturally depends on the degree of weakening and also on the specific arrangement of each region on the base body 5.

[0059] Because areas 21 and 22, with higher flexural stiffness, are located between areas 19, 24, and 26, which have lower flexural stiffness, these areas do not deform and form surface sections 38 and 39 that remain essentially flat. These surface sections 38 and 39 form acute angles with the sieve belt 3. The angle α between the first surface section 38 and the sieve belt 3 opens in the direction of movement 4 of the sieve belt 3, thus exerting a suction force on the sieve belt 3 and / or on the liquid emerging from the mixture 36. Conversely, at the second surface section 39, the angle β between the surface section 39 and the sieve belt 3 closes in the direction of movement 4 of the sieve belt 3, thereby exerting pressure on the sieve belt 3 and / or on the liquid emerging from the mixture 36.By precisely adjusting the angles α and β, turbulence can be generated in the fiber suspension 36 on the screen belt 3, influencing the fiber orientation and thus affecting the formation of the material mixture 36. Precise knowledge of the shape and position of the surface 12 with its surface sections 38 and 39 is essential because not only the pressure in the chamber 7, but also the screen belt 3 with the material mixture 36 on it exerts a force on the deformable wall 11. By directly detecting the position and deformation of the wall 11 using the device 17, it is always possible to precisely adjust the angles α and β, even under changing operating conditions.

[0060] The angles α and β can be adjusted by the size of the vacuum in chamber 7, whereby the ratio of these angles can be influenced by the geometry of the base body and in particular by the selection and arrangement of the areas 19, 24 and 26 with lower bending stiffness.

[0061] In the illustrated embodiment, for example, the angle α is half the size of the angle β because the area 19 with lower bending stiffness is arranged off-center on the wall 11. Other angle ratios are of course also possible depending on the desired result, by repositioning the areas 19, 24 and 26 with lower bending stiffness accordingly or even selectively omitting them.

[0062] Regarding the extent of the maximum adjustable angles α and β, these can be set, for example, from 0° to 1°, 2°, 3°, 4°, 5°, 6° or more.

[0063] In Fig. 10Figure 1 shows an embodiment of the invention with two adjacent chambers 7 which can be pressurized (overpressure or underpressure) independently of each other. A device 17 for detecting the deformation and thus the change in position of the wall 11 due to changes in pressure in the chambers 7 is arranged in each of the two chambers 7.

[0064] In this embodiment of the invention, it is also shown that the surface 12 facing the sieve belt 3 can be corrugated, which can generate additional turbulence in the fiber suspension.

[0065] In the Fig. 11 and 12Figure 1 shows an embodiment of the invention in which the wall 11 itself is essentially non-deformable. To allow for a change in position of the wall 11, a region of lower flexural strength is provided in the transition region 24 to the side wall 14. Furthermore, regions 26, 42, 43 with lower flexural stiffness are arranged in the region of the other side wall 13. The regions 26, 42, 43 with lower flexural stiffness have grooves 44, 45 in the edge regions of the wall 13 and a groove 27 in the central region of the wall 13. If the wall 13, for example, in the unpressurized state (ambient pressure) of the chamber 7, the Fig. 11Since the wall 11 has the straight shape shown, it is also straight and its surface 12 lies parallel to the sieve belt 3. If, on the other hand, there is a negative pressure in the chamber 7, the side wall 13 bends inwards, allowing the deformable wall 11 to pivot around the area 24 with lower bending strength, like a joint, tilt downwards on the side of the side wall 13 and the surface 12 of the wall 11 forms an angle α > 0° with the sieve belt.

[0066] In another embodiment of the invention, not shown in the drawings, the area 24 with lower bending strength could also be arranged elsewhere, designed differently or omitted altogether if the wall 11 is, for example, elastic, i.e. flexible, enough to allow the desired change of position in the area of ​​the right wall 13.

[0067] It is understood that (as with all other embodiments shown) the in Fig. 12The depicted shape of the drainage strip 1 could also represent the state in which chamber 7 is depressurized and the drainage strip 1 is in Fig. 11 The depicted shape can be assumed when chamber 7 is pressurized. Likewise, it is possible that the drainage bar 1, in the unpressurized state, takes on a shape between the sections shown in the Fig. 11 and 12 depicted forms, under overpressure the in Fig. 11 depicted form and under negative pressure the in Fig. 12 takes on the depicted form. Reference symbol list: 1 drainage strip 29 Nut 2 Longitudinal direction, arrow 30 rear edge 3 screen belt 31 Wear part 4 Arrow 32 tongue and groove joint 5 basic body 33 bar 6 bar 34 Supporting body 7 chamber 35 screw connection 8 Pressure line 36 mixture 9 Line 37 liquid 10 --- 38 Area section 11 deformable wall 39 Area section 12 Area 40 --- 13 side wall 41 Inner surface 14 side wall 42 area with lower 15 lower part Bending stiffness 16 Front wall 43 area with lower 17 Furnishings Bending stiffness 18 floor area 44 Nut 19 Area with lower bending stiffness 45 Nut 20 Top 21 Area with higher bending stiffness 22 Area with higher bending stiffness 23 Nut 24 Area with lower bending stiffness 25 Nut 26 Area with lower bending stiffness 27 Nut 28 leading edge

Claims

1. Dewatering bar (1) of a paper machine, wherein the dewatering bar (1) has a base body (5) with a longitudinal direction oriented transversely to the direction of movement (4) of a wire belt (3), wherein the base body (5) has at least one pressure-tight closed chamber (7) extending in the longitudinal direction (2) of the dewatering bar (1), wherein the chamber (7) has a connection to a pressure line (8), a wall (11) with a surface (12) facing the wire belt (3) of the paper machine and side walls (13, 14) connected to the wall (11), and wherein the position of the wall (11) of the chamber (7) is changeable, characterized by a device (17) for detecting the change in position of the wall (11) due to changes in pressure in the chamber (7).

2. Drainage strip according to claim 1, characterized by the fact that the device (17) is a sensor, in particular a tilt sensor or a displacement sensor, and / or that the device (17) is arranged in the chamber (7).

3. Drainage strip according to one of claims 1 or 2, characterized by the fact that the wall (11) is deformable and preferably has areas (19, 21, 22) with different bending stiffnesses.

4. Drainage strip according to claim 3, characterized by the fact that a region (19) which has a lower bending stiffness compared to an adjoining region (21, 22) of the deformable wall (11) is inclined in the longitudinal direction (2) of the drainage strip (1) or to the longitudinal direction (2) of the drainage strip (1).

5. Drainage strip according to one of claims 1 to 4, characterized by the fact that in a transition area from at least one side wall (13, 14) to the wall (11) a region (24) is arranged which has a lower bending stiffness compared to the adjoining regions of the respective adjoining side wall (13, 14) and wall (11).

6. Drainage strip according to one of claims 1 to 5, characterized by the fact thatat least one side wall (13) has areas (26, 42) with different bending stiffnesses.

7. Drainage strip according to one of claims 3 to 6, characterized by the fact that a region (19, 24, 26, 42, 43) with a lower bending stiffness has a groove (23, 25, 27, 44, 45) which is preferably open inwards towards the chamber (7).

8. Drainage strip according to one of claims 1 to 7, characterized by the fact that two or more than two pressure-tight closed chambers (7) are present, which extend in the longitudinal direction (2) of the drainage strip (1) and are arranged next to each other, and that each chamber (7) has a separate connection to a pressure line (8).

9. Drainage strip according to claim 8, characterized by the fact thatEach chamber (7) has a wall (11) that can be changed in its position and has a surface (12) facing the wire belt (3) of the paper machine, and each chamber (7) is assigned a device (17) for detecting the change in position of the wall (11).

10. Drainage strip according to one of claims 1 to 9, characterized by the fact that the surface (12) facing the sieve belt (3) has a first surface section (38) which encloses a first acute angle (α) with the sieve belt (3) which opens in the direction of movement (4) of the sieve belt (3).

11. Drainage strip according to claim 10, characterized by the fact thatin the direction of movement (4) of the sieve belt (3) after the first surface section (38) a second surface section (39) is arranged, which encloses a second acute angle (β) with the sieve belt (3), which closes in the direction of movement (4) of the sieve belt (3), and that, if necessary, at least one further surface section, which e.g. runs parallel to the sieve belt (3), is arranged between the first surface section (38) and the second surface section (39).

12. Drainage strip according to one of claims 1 to 11, characterized by the fact that viewed in the direction of movement (4) of the sieve belt (3), it has a strip (6) made of wear-resistant material, for example ceramic, on at least one front edge (28), optionally additionally on a rear edge (30), which is preferably detachably attached to the base body (5) on the front and optionally rear edge (28, 30).

13. Drainage strip according to claim 12, characterized by the fact thatthe strip (6) is attached at the front and, if applicable, rear edge (28, 30) to a support body (34), for example made of glass fiber reinforced plastic, which is detachably arranged on the base body (5).

14. Drainage strip according to one of claims 1 to 13, characterized by the fact that the basic body (5) consists of at least two parts, namely a lower part (15) for attachment to a support rail, and an upper part (20) which forms the wall (11) of the chamber (7).

15. Wire section of a paper machine with at least one dewatering bar (1) and a wire belt (3) which moves across the dewatering bar (1) transversely to its longitudinal extent (2), characterized by the fact that the drainage strip (1) is designed according to one of claims 1 to 14.

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