FI91091C - Paper machine dewatering and wire loading device - Google Patents

Description

91091

Paper machine dewatering and wire loading device Awattnings- och virabelastningsanordning for en pappersmaskin 5

The invention relates to a dewatering * located in the two-wire zone of a former paper machine and to a wire loading device for applying to the paper machine wires, preferably over their entire width, a mechanical load by applying pressure pulses to the fiber layer or web between the wires. forming a web and / or controlling transverse profiles of web properties such as dewatering, filler distribution, formation and / or retention profiles, and each device comprising forming strips with which a coil is arranged to be wound, a wire is arranged inside the opposite wire loop. the side is arranged substantially parallel to the running of the wires to drag the inner surface of the wire loop.

Several different forming members are used in the web forming sections of the paper machine. The main purpose of these members is to provide a pressure pulsation in the resulting fibrous layer, which promotes the dewatering of the forming web and at the same time improves its formation. In addition, several different forming shoes, usually with a curved strip cover, are previously known, over which the overlapping forming wires and the web between them are curved. In the area of these forming shoes, water is drained mainly through the wire on the outer curve side due to the tightening pressure which the dewatering in the centrifugal force field helps. The molding cover of the Formation-25 shoe provides a pressure pulsation that promotes dewatering and improves web formation.

In addition, various suction boxes and rolls, register rolls, forming and foil strips, and scrapers are previously known for providing a pressure difference and pulsation in the fibrous layer formed to promote web formation and dewatering.

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As an example of the state of the art most closely related to the present invention, reference is made to U.S. Patent Nos. 2,881,676, 3,438,853, Patent Application WO 91/02842, DE Application Nos. 4,002,304 and 4,002,305, and FI Application Publication 84,502 and FI Application 903374.

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In addition, the applicant's FI patent application 912630 discloses a wire loading device as defined at the outset, in which it is considered new that the loading device stacks a plate-shaped spring blade, the side of which is arranged to press the spring blade is attached to the body part of the loading device from outside its towing area, the body part and / or the load devices of which provide a load force which bends the spring blade in the machine direction and which produces said pressure pulse.

Em. In a preferred embodiment of the FI application, the spring blade extends in the transverse direction of the web and the wire 15 over its entire width as a uniform structure. Most preferably, the spring blade is matched to the running of the "myo" sock and the web, which helps to prevent damage to the fiber coils and increases the flexibility of the spring blade. This spring-loaded loading device is suitable for use in the web-forming section in several different positions, usually in the double-wire area, but also even in the groove area of the kit. 20 This load device enables versatile cross-section profile controls and conditions, in which closed and on-line control systems based on the measurement of different profiles can be used, if necessary.

The general object of the present invention is to further develop the forming wire loading device disclosed in the above-mentioned FI application 25 912630.

The specific object of the invention is to provide such an apparatus applying a loading device according to the above-mentioned FI application, in which no water entrains the wire in the harmful amount in front of the spring blades.

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It is a further object of the present invention to provide a dewatering and forming wire loading apparatus in which the spring blades of the apparatus and the opposing wire guiding and dewatering forming strips of the apparatus are made interoperable in a more advantageous manner.

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It is a further object of the present invention to provide a dewatering and wire loading device in which the forming members are not "hard to hard" and the device is made flexible so that pulps and other contaminants cannot cause equipment damage.

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In order to achieve the above and later objectives, the invention is essentially characterized in that the strips of the dewatering and wire loading device are arranged alternately in the region of the opposing wire loops and that the spring strips are arranged to be drawn into the opposite ends of the threads.

The invention makes it possible to prevent the accumulation of water in front of the spring blades of the loading device by alternating the spring blade units and the forming strips 20 inside each wire loop in a two-wire zone and setting their mutual distribution so that the two cross-sections

When, according to the invention, the rigid forming strip and the flexible spring blade 25 of the loading device work together, a flexible loading gap is provided through which the wires and the web between them pass so that the pulp clumps and the like do not cause equipment failures.

According to the invention, forming strips and spring blades of a loading device within opposite wire loops are obtained by alternating a two-wire forming zone with a very small amplitude, in which variation in dewatering directions promotes web formation and improves formation.

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The load and dewatering unit according to the invention can be constructed either by combining the structures in one or two frames into a compact structure or even as separate units comprising a spring blade and a forming strip, which are placed in the required number in succession.

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The structure according to the invention can improve the control of the dewatering directions and the shape of the dewatering pressure pulse. Other advantages and functions of the invention will become apparent from the following description.

The invention will now be described in detail with reference to some application examples of the invention shown in the figures of the accompanying drawing, to the details of which the invention is in no way narrowly limited.

Figure 1 shows a hybrid former in which the invention has been advantageously applied.

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Figure 2 shows a kit forming a dewatering and wire loading device according to the invention.

Figure 3 shows a machine direction vertical cross-section of a dewatering-20 and wire loading device according to the invention arranged in a straight-flow two-wire zone.

Figures 4A, 4B and 4C show different variations of the mutual arrangements of the forming strip and the spring blade of the dewatering and wire loading device according to the invention.

Figure 1 shows an example of a hybrid former with wire-pulling loading devices 10a, 10b, 10c in several different positions, the details of the structures of which are shown in the applicant's above-mentioned FI patent application 912630.

The loading device 10 best seen in Figures 4A, 4B and 4C comprises a thin plate-shaped spring blade 11 30, the tip 11a of which may be rounded. The spring blade 11 extends as a uniform structure over the entire width of the web W and the wires 40.50. Spring blade 11 loads and drags

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5 91091 wire 40/50 inner surface on its wide side. At its opposite edge, a spring blade 11 is fastened by a piece 14 to the body part 12 of the loading device 10.

It is essential for the structure and material of the spring blade 11 that the blade 11 acts as a disc spring 5, which is curved at one edge to produce a drag and load pressure against the wires 40 and 50. The blade 11 is stationary and preferably drags the wire 40.50 loaded by the "myotassuka". Thus, the fastening parts 12,14 of the blade 11 are in the direction of travel of the wires 40,50 before the towing and loading area of the spring blade 11.

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The spring blade 11 of the loading device is a reversibly flexible plate-like spring material. The ratio of the length L of the spring blade 11 to the thickness S of the blade plate material is in a certain range L / S = 10 ... 1000. Optimal applications are usually found in the range L / S = 300 ... 500. Said ratio L / S also depends on the material of the spring blade. As the steel material, 15 wear-resistant spring steel, e.g. stainless steel, is preferably used. Some plastic materials and composite and sandwich structures may also be considered. The spring blade 11 operates in such a way that loading the blade 11 with the loading devices 20,21 causes the shape of the blade plate to bend in the machine direction with a relatively large radius of curvature Rø «200 ... 1000 mm according to elastic conditions and loads and a desired width of laa-20 against the wire 40.50. The material of the spring blade 11 must therefore be suitable for its spring properties and must not be permanently deformed. The spring blade 11 is dimensioned and the spring properties of its material are generally selected so that the spring constant of the bending of the blade per meter of width is in the range 1.6 ... 0.02 kN / mm, preferably in the range 0.1 ... 0.03 kN / mm. The spring constant, in particular in composite structures, can be different in the machine direction and in the cross direction.

In Figure 1, a form shown in one embodiment of the present invention comprises a lower wire 40 guided by guide rollers 43. After the headbox 45, the lower wire has a single-wire initial portion 40a into which the headbox 45 feeds a lip jet J. The two-wire zone begins at the guide roll 54 of the upper wire 50. This is followed by a unit 60 with a two-wire zone with loading devices 10 and forming strips 66. After unit 60, the two-wire zone generally curves with a hollow surface 55 'forming roll 55, followed by a forming shaft 5 with a strip cover 42b with a strip cover 42. T , at which there are planar boxes 47. The upper wire 50 is separated from the lower wire and the web W is transferred over the suction roll 49 to the pick-up felt 70 in the suction zone 71a of the pick-up roll 71. If the unit 60 is not used, the running of the upper wire 50 may follow the path 50 'shown by the dashed line.

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There are loading devices 10 according to the invention in connection with the unit 60 and the opposite subunit 46 in a new manner, which will be described in more detail in Fig. 3. At the forming roll 55, the loading device 10a acts inside the loop of the lower wire 40, and correspondingly there is a loading device 10b on the cover 42 of the forming shoe 41b. On top of the leveling box 47 15 is the last loading device 10c. One or more loading devices 10 may be in or out of use as needed.

Figure 2 shows a two-wire former in which loading devices 10d and 10e are applied. The lip portion of the headbox 45 feeds the pulp suspension jet J to the forming roll G, 20, after which a two-wire zone begins with the forming roll 43a. Opposing the covering wire 50, in the region of the groove G, there is a first loading device 10d and then, in the two-wire curved sector of the forming roll 43a, a second loading device 10e. After the forming roll 43a, the wires 40.50 have a common straight run with the units 601 # 46j according to Fig. 3 and then the corresponding inverted units 602, 462 · 25.

The two-wire zone curves downward in the sector of the latter forming roll 43b, which sector may have a loading device 10. The web W is separated from the covering wire 50 and follows a carrier wire 40 from which the web W is transferred to the pick-up fabric 70 in the suction zone 71 of the pick-up roll 71.

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Some preferred embodiments of the invention will now be described in detail with reference to Figures 3 and 4.

Fig. 3 shows a dewatering and wire loading unit 5 according to the invention, which encloses an upper unit 60 arranged inside the wire loop 30 and a lower unit 46 arranged inside the five loop 40, which may be in the position shown in Fig. 1 or in the positions 46j, 60j and / or 462 shown in Fig. 2 and / or 46 in other positions, especially in two-wire drainage and formation zones with a straight flow. According to Figure 3, the forming strips 66Aj, 66A2, 66A3, 66A4 and 66A5 are arranged alternately inside opposite wire loops. In connection with the first forming strips 66A j and 66A2, a loading device is integrated, the spring blade 11 of which is placed between the body of the strip 66 and the body 21a of the loading device 10. The load hose 20 of the spring blade 11 is also supported on the body piece 21a. Each spring strip 66A j to 66A5 cooperates with the spring blade 11 of the loading device 10, the drag and load area 15 of which is located at the wear strip 67 of the forming strip 66 according to Fig. 3. The wear pieces 67 of the forming strips 66, e.g. ceramic, and the drag areas of the spring blades 11 form a flexible load gap through which the wires 40 and 50 and the web between them pass. Said load range is thus flexible so that, for example, pulp clumps do not cause equipment failures. In addition, especially when using the solution of Fig. 4B 20, a two-wire substantially straight run with low amplitude ripple is obtained. This, together with the alternation of dewatering directions, promotes web formation.

The forming strips 66 shown in Figures 3 and 4 have, for example, a ceramic wear piece 67, the planar surface of which slides against the inner surface of the wire 40 and 50 lubricated by the water 25 leaving the web. The pieces 67 are connected by a dovetail joint 68 to the forming strips 66. The leading edge 67 of the pieces has a ceramic 69 which effectively scrapes water from the inner surfaces of the wires 40 and 50.

The forming strips 66 and the loading devices 10 of the upper unit 60 and the lower unit 46 are arranged in the upper unit 60 in connection with the frame beam 60a and in the lower unit 46 in connection with the frame beam 46a, respectively. Of the said frame beams 60a and 46a, only the inner sides are shown. The dewatering of the subunit 8 takes place mainly by gravity, if necessary with the aid of suction, and the upper unit 60 uses suction-assisted dewatering, e.g. in AUTO-SLICE (trademark) arrangements known per se.

Instead of the unit shown in Fig. 3, in which the structures are connected to the frame as a compact unit, separate combinations of forming strip 60 and loading device 10 can also be used in two-wire zones in different positions, such as positions 10b and 10c or the like shown in Fig. 1. The unit 46,60 shown in Figure 3 improves the control of the variation of the dewatering directions and the shape of the dewatering pressure pulse.

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Figures 4 show different variations of the different inter-arrangements of the forming strip 66 and the spring blade 11 of the loading device 10. According to Fig. 4A, the candle 11a of the spring blade 11 is in the region of the drag surface of the wear member 67 of the forming strip 66A and the drag area of the spring blade 11 is completely in the region of the drag of the body 67. In the structure 15 of Fig. 4A, the paper web W is mainly subjected only to a pressure pulse, which does not substantially affect the dewatering, but to other properties of the web W, such as formation.

Fig. 4B shows an arrangement in which the drag area of the spring blade 11 is just before the drag area of the wear member 68 of the forming strip 66B. In this case, the pressure pulse at the bellows 69 20 of the body 68 corresponds to the pressure pulse possibly caused by the applied vacuum and the tightening of the wire 50, to which is added the pressure pulse caused by the pressure of the spring blade 11. The latter pressure pulse acts through the drag region of the blade 11 by pressing the wires 40.50 against each other, which effect is advantageous over the vacuum because it does not seek to separate the wires 40.50 from each other, which may cause the structure of the web W 25 to break. 4B, a list 66B and the blade-yhteisvaikutukses of water is removed påaasiallisesti the direction of arrow j direction of the split.

Fig. 4C shows an arrangement in which the area of action of the spring blade 11 on the wire 40 extends both before and to the drag area 67 of the wear member 67 of the forming strip 66C. In this case, the lower wire 40, together with the spring blade 11, forms a wedge space T, the wedge angle of which is denoted by t, in the region of the proximity of the louver 11a 91091 9 in the direction of travel of the wires 40/50. The magnitude of said angle t is usually in the range t = 0 ° ... 5 °. At the corner of T-opening space T to remove water from the lower wire 40 the direction of arrow A3 direction in a known foilivaikutuksella. In addition, water exits through the upper wire 50 before the apex 69 of the 5 body 67 in the directions and points of arrows Aj and A2.

Adjusting or adjusting devices can be provided in the support pieces 12, 14 and / or in the load hose 20 and / or in the other loading device of the forming strips 66A, 66B and 66C and / or the spring blade 11, by means of which the loading stations 66 and e.g. to the various positions shown in Figures 4A, 4B and 4C as well as their intermediate positions.

The following claims set forth within the scope of the inventive idea, the various details of the invention may vary and differ only from those exemplified above.

Claims (10)

10 A dewatering and wire loading device placed in the two-wire zone of a former paper machine, by which a mechanical load is applied to the paper machine wires (40, 50), preferably across their entire width, by means of which a pulse of fibers or web (W) between the wires (40, 50) is applied to promote dewatering from the web (W), improve web formation and / or control transverse profiles of various web properties such as dewatering, filler distribution, formation and / or retention profiles, and which device mates with forming strips (66) to co-operate with each other. 40/50) are provided with wire loading devices (10) comprising a plate-shaped spring blade (11), the side of which is arranged substantially parallel to the flow of the wires (40,50) to drag the inner surface of the wire (40,50) loop, characterized in that the dewatering and wire loading device forming strips (66Aj - 66 / ^) is arranged alternately inside the opposite wire loops 15 (40,50) and that the spring blades (11) are arranged to drag the inner surfaces of the wires (40,50) in the region of the forming strip (66) inside the opposite wire loop and / or in the running direction of the wires (40,50) substantially immediately before that. Device according to Claim 1, characterized in that the forming strips (66) 20 and / or the wire loading devices (10) and / or their loading elements (20) are arranged to be adjusted or adjusted by the spring strips (11) of the forming strips (66) and the loading device (10). ) for adjusting the mutual position and / or the load applied to the wire (40.50) by the spring blade (11). Device according to claim 1 or 2, characterized in that the device comprises two opposing units (46, 60) in a substantially straight two-wire zone, each of which has alternating oppositely forming strips (66) and a spring blade (11) in the running direction of the wires (40, 50). load devices (10) (Figure 3). 30 I! 91091 11 Device according to one of Claims 1 to 3, characterized in that the device comprises two opposing units (60, 46) comprising body parts (60a, 46a) in connection with which the forming strips (66) and the loading devices ( 10) is alternately fastened. 5 Device according to one of Claims 1 to 4, characterized in that the forming strips (66A) and the towing area of the spring blade (11) of the wire loading device (10) are arranged on the inner surfaces of the opposite wire loops (40, 50). (Fig. 4A). Device according to one of Claims 1 to 4, characterized in that the towing area of the spring blade (11) of the wire loading device (10) inside the opposite wire loops (40, 50) is arranged substantially immediately before the opposite wire loop (50) in the direction of travel. the front tip (69) of the drag area of the wear piece (68) of the forming strip (66B) inside (Fig. 4B). 15 Device according to one of Claims 1 to 4, characterized in that the region after the traction region of the spring blade (11) of the wire loading device (10) is arranged to form a wedge space (T) extending in the direction of flow of the wires (40, 50). (66C) to the drag piece (67) and each wedge space (T) is adapted to remove water from the web (W) by its foil action (arrow A3) (Fig. 4C). Device according to one of Claims 1 to 7, characterized in that the opposite load and dewatering units (60, 46) have at least one, preferably a first, forming strip (66Aj) and a load device (10) integrated in the common body (21a). ) (Figure 6). Device according to one of Claims 1 to 8, characterized in that the device is arranged on the initial part of the two-wire zone of the hybrid former (Fig. 1). 30 12 Device according to one of Claims 1 to 8, characterized in that the device is arranged in the two-wire zone of the kit former, preferably after the forming roll (43a) in the region of the forming crystal (G), on the next upward-sloping two-wire zone 5 (60 ^ 46 ^ 602,462), after which the web (W) is arranged to follow the supporting wire (40) (Fig. 2). I! 91091 13