FI93039C - Device fitted to the paper guide roll - Google Patents

Description

5,93039

Device fitted to the paper guide roll

Anordning anordnad i förbindelse med en pappersledningsvals

The invention relates to a device arranged in connection with a paper guide roll, which can reduce the air flows interfering with the support contact between the cylinder liner cylinder and the paper web and the resulting paper web bagging and similar disadvantages, and which device 10 comprises a paper web inlet and side roll on opposite side.

The paper guide rolls are used in a number of different positions, typically between the press section and the drying section, and between the compact press-ink assembly of the press section and its separate press.

A disadvantage of the prior art paperinjohtoteloissa is that it induces a rotary motion around the paper guide roll air flow which produces a pressure in the paper web and the paper guide roll inlet side sul-20 in the descending nip positions. This overpressure tends to detach the paper web from the paper guide roll, and the resulting air bag causes instability and wrinkles in the running of the paper web, and even web breaks.

Particularly particularly, the above problem arises in a press section having a compact press roll combination which; forms three press nips (a press section marketed by the applicant under the trademark "Sym-Press II") and in which the press section has a fourth separate nip pi. This separate nip is formed between the smooth-faced upper roll and the hollow-faced lower roll inside the press felt. From the smooth surface of this upper roll 30, the paper web is guided by a paper guide roll to the lower surface of the straight run of the drying wire of the drying section. It is in the context of the latter paper guide roll that the problems discussed above come to the fore. These problems are exacerbated by the increasing speeds of paper machines.

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Efforts have been made to reduce these disadvantages by increasing the tensile stress of the paper web when entering the paper guide roll, but this causes: detrimental elongation in the web, thereby deteriorating the quality characteristics of the paper 2 93039. Said problems are particularly great with dense airtight paper grades. For example, with SC papers the mentioned problem already starts to appear when the web speed rises above - 1000 m / min, while with e.g. e.g. newsprint the problems only appear when the web speed 5 is above ~ 1400 m / min.

The management of said problems is also hampered by the congestion around the paper guide roll and the fact that the paper guide roll usually has to be moved to different positions in connection with the head export of the paper web and the normal driving situation. This transfer also requires its own space, which contributes to the difficulty of locating the devices to be fitted to the paper guide roll.

Efforts have been made to prevent the above-mentioned drawbacks by grooving the cylinder liner of the paper roll, but such drawbacks, especially at high speeds, have not been avoided. The above-mentioned point of the paper guide roll has thus become a bottleneck limiting the speed increase of the paper machine.

It is an object of the present invention to provide new solutions to the problems discussed above.

In order to achieve said and later objects, the invention is essentially characterized in that said housing beam is fixedly connected to the paper guide roll bearing brackets or associated parts, that said housing beam has closure portions at a small clearance from the paper guide roll housing and that said closure an enclosure with an air discharge duct or ducts outside the housing beam.

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The device according to the invention prevents air currents around the paper guide roll induced by the rotational movement of the paper guide roll. In addition, box beam device according to the invention, a shut-off mode, which appears remarkably large paper guide roll of web travel 35 the trailing side in the direction invested sector, and in this close state is arranged in either an active or passive air outlet is blocked 3 93 039 of harmful air currents emergence of the paper guide roll and the paper input side of the track wagers closing between the nip positions.

When the device according to the invention and its housing beam are fixedly placed in connection with the bearing supports or associated arms of the paper guide roll 5 for pivoting with the paper guide roll, the housing beam and its closing space delimiting closure parts can be placed at a very small clearance from the paper guide roll cylinder shell. In the direction of rotation of the paper guide roll, the first of said closures has a considerably lower flow resistance than the second or second closure part, so that more air enters said closure space through said first closure part than exits through said second closure part. Thus, the overpressure generated in the enclosure is discharged through the deaeration duct arranged in the housing beam, either freely to the outside air or with the aid of a suction 15. Said closure parts can also, if necessary, be provided with padded protective parts which prevent the surface of the paper guide roll from being damaged. If necessary, a paper guide roll with a groove can be used in connection with the device according to the invention. In this case, however, the groove may be relatively shallow and sparse.

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In the following, the invention will 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.

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Fig. 1 shows a schematic side view of the press part for the application environment of the invention and the subsequent initial part of the drying part, between which the device according to the invention is applied.

Fig. 2 shows a first embodiment of the device according to the invention in the driving position, and Fig. 2 is at the same time a larger scale view of the area DET marked in Fig. 1.

Fig. 3 shows the device of Fig. 2 with the paper guide roll 35 in the web head position.

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Fig. 4 shows a second embodiment of the device according to the invention in a manner similar to Fig. 2.

Fig. 5 shows a cross-sectional vertical section of the machine at the plane V-V shown in Fig. 2.

Fig. 6 shows a vertical cross-section VI-VI in Fig. 4 in a manner similar to Fig. 5.

A typical and per se known application environment of the invention will first be described with reference to Fig. 1. It should be emphasized, however, that the invention can also be applied in other environments substantially different from Figure 1. The paper web W felted on the forming wire 10 is transferred by a pick-up roll 12 to the lower surface of the pick-up fabric 11, where it is fed to the first press nip Nx. This press nip Nj is formed between the press rolls 14,15 and the press felts 11,12. On the surface of the felt 11, the web W is transferred over the suction sector of the press suction roll 15 to a second nip N2 formed between the said suction roll 15 and the central roll 16 provided with a smooth surface 16 '. In connection with the roller 16, the press roll 17 of the third nip N3 of the press part is formed and the press felt 18 above.

In Fig. 1, from the smooth surface 16 'of the panel 16, the paper web W is detached as a short free pull W0 and transferred by means of a paper guide roll 19 to the upper surface of the lower press felt 20. This takes the web W to the fourth separate press nip N *. This press nip N <, is formed between a lower hollow surface press roll 22 inside said felt loop 20 and an upper larger diameter 20 'press roll 21 with a smooth surface 21'. From the smooth surface 30 'of the upper press roll 21, the web W is detached as a short free pull Wx and transferred to the lower surface of the drying wire 24 by a paper guide roll 27. The drying wire 24 is guided by a turning roller 25 above the paper guide roll 27, from which the drying wire 24 has a direct flow to the first drying cylinder 28 or the lead-in cylinder, followed by a turning cylinder 29. The drying wire 24 between the guide roller 25 and the cylinder 28 the straight run has a blow suction inside the wire loop 24! 5,93039 boxes 26a, 26b. These provide a vacuum field SA for said run of the drying wire 24, which securely attaches the web W to the lower surface of the drying wire 24.

A device 100 according to the invention is arranged in connection with the paper guide roll 27 in the incoming direction of the web W on its discharge or back side, which will be described in more detail below, mainly with reference to Figures 2-6. First, a first embodiment of the device according to the invention will be described with reference to Figures 2 and 3.

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In Fig. 2 the device 100 is shown in the driving position, i.e. in the normal operating mode of the paper machine, and in Fig. 3 in the head-pulling position, in which the narrow head-strip R is passed first through the press section and then through the drying section. The device 100 according to the invention comprises a housing beam 30 with end portions 31a and 31b and enclosed housing parts K1, K3 and K3 and an enclosing space T adjoining them, from which an air discharge duct 35 leads outside the housing beam 30. The housing beam 30 is bounded at the top by walls 33 and at the bottom by a wall 34. The housing beam 30 is rigidly attached at its ends 31a and 31b to the drug guide rollers 40 of the paper guide roller 27. The bearing supports 40 are in turn articulated by horizontal shafts 42 through. The bearing brackets 40 are arranged to be pivoted by hydraulic cylinders 43 fixed at one end by articulated pins 44a to the projections 47 and at the other end by pivot pins 25 44b to bearing brackets 40. The pairs of hydraulic cylinders 43 The housing beam then pivots with the paper guide roll 27 and the corresponding positions are indicated by reference numerals 30A and 30B.

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On the outlet side of the paper guide roll 27, the housing beam 30 delimits the closing air space T. This space T is delimited on the inlet side by the closing portion 32a and on the discharge side by the closing portion 39a connected to the housing portion K3. At the tip of the closure portion 32a and on the inner surface of the closure portion 39a, a padding portion made of felt, rubber 35 or plastic may be used so that said closure portions 32a and. 39a can be introduced at a very small distance from the cylindrical surface of the paper guide roll 27. Said distance is typically 0.5-5 mm, most preferably -1 mm. Said clearance may be small also because the housing beam 30 is fixedly mounted on the bearing brackets 40 with it to pivot into positions 30A and 30B.

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In the direction of rotation of the paper guide roll 27, the first closure portion 32a is linear, while the second or second closure portion 39a is longer and sector-like extending to sector b. The size of said sector b is generally selected from b = 2 ° ... 10 °, preferably b = 4 ° ... 7 °. Thus, the flow resistance of the closure portion 32a 10 is substantially lower than that of the latter closure portion 39a. Thus, as a result of the rotation of the paper guide roll 27, more air enters the closure space T than is exited through the closure portion 39a, and said air is discharged through the passage 35.

15, the paper guide roll 27 of the downstream sector, a <60 ° ... 150 °, preferably a «p 90 (Figure 3), extending box beam 30 closing the space T lead to the air exhaust channels 35 of the box beam 30 outside.

According to Figures 2, 3 and 5, said air duct 35 is bounded by horizontal walls 35a, 35b connected between the ends 31a, 31b of the vertical walls 36. The vertical partitions 36 contribute to stiffening the structure of the housing beam 30.

According to Figures 4 and 6, deaeration pipes 37 from the shutter space T are arranged inside the housing beam 30 between the horizontal walls 35a and 35b. The outlet pipes 37 are connected at their outer end to a transverse horizontal pipe 38 connected by a flange 39a to the suction side of a suction pump (not shown), as illustrated by the arrow VAC in Fig. 6.

30 The cylinder liner of the paper guide roll 27 is preferably chrome-Teflon coated. According to the figures, the paper guide roll 27 is provided with an external groove 27 '. This groove 27 'is relatively shallow and sparse; typically the grooves 27 'have a depth of -1 mm, a width of 2 mm and an axial pitch of 6-12 mm and the proportion of open surface is ~ 10-15% of the cylinder surface.

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The device 100 described above operates as follows. The lower felt 20 of the separate nip N <, induces an air flow in the direction of the arrows F: and previously part of this flow with air induced by the rotation of the paper guide roll 27 has entered The device 100 according to the invention prevents this detrimental phenomenon, so that by closing the space T and the corresponding sector of the paper guide roll 27, the device 100 prevents air from rotating with the jacket of the paper guide roll 27.

The closure portion 32 on the inlet side of the housing beam 30 conducts air in the direction of the arrows F2 away from the roll 27 and outside the housing beam 30.

The air entering the space T in the direction of the arrows F3 exits in the direction of the arrows F * through the duct 35 or the pipes 37. This deaeration according to Figures 4 and 6 is assisted by a vacuum (VAC) sucked through the pipe 38.

The housing beam 30 delimits with the felt guide roller 23 a narrow channel C through which the felt 20 induces an air flow in the direction of the arrows F3, which in turn prevents the air induced by the cylinder 29 from interfering with the flow of the web W.

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Figure 3 shows the paper guide roll 27A and a box beam 30A of the head-posture, in which the air pipe 19a coming shower S is removed päänvientrisauha R press roll 21 from the smooth face 21 'and the head-tail is controlled by the direction of arrow R direction of the drying wire 24 at a 25 lower surface alipaiaekenttä SA to infect. The retention of the headband R on the drying wire is also facilitated by the air flow Fs discharged from the duct 35 of the housing beam 30 (Fig. 2).

With lower web speeds and / or less dense papers, you can get by. In general, with the passive device according to the invention shown in Figures 2 and 3, which has a discharge channel 35 free from the closed space T to the external space. At higher web speeds and / or denser paper grades, especially SC papers, it is generally more advantageous to apply the active design according to the invention, in which the deaeration ducts are connected to a vacuum source for evacuating the enclosure T.

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

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Claims (11)

Device (100) arranged in conjunction with a paper conduit roller (27), with which one can reduce air currents interfering with the support contact between the cylinder sheath (27 ') of the paper conduit roller (27) and the paper web (U) and paper forming in the paper web due to of these and corresponding disturbances, and the device (100) comprises a case beam (30) arranged on the opposite side of the entrance and tangent sector of the paper web (W), characterized in that said case beam (30) is stationary coupled to the bearing support means (40) of the paper guide roller (27) or to parts connected thereto, that there are closure members (32a, 39a) in communication with said case beam (30) which are at a small distance from the men of the paper guide roller (27) and that said closure portions (32a, 39a) restrict a closure space (T) within the casing beam (30) and between them, from which space (T) is an air flow duct or channel smiles (35.37) outside the case beam (30). Device according to claim 1, characterized in that 20 of said closure parts (32a, 39a) are those which in the rotation direction of the paper guide roll (27), the first closure part (32a) is linear and the later closure part (39a) extends over a considerable sector (b) such that the air flow resistance of the first closure portion (32a) is substantially smaller than the flow resistance of the latter closure portion (39a). Device according to Claim 1 or 2, characterized in that the device (100) is arranged between the last nip (N *) in the pressing portion of the paper machine and the drying portion. 30 Device according to claim 3, characterized in that the device (100) is arranged in connection with such a paper conduit roller (27) which is arranged in contact with a press roller (21) with a smooth surface (21 ') above the separate press (N4). ) of the papermaker's press portion 35 and at the same thread in contact with the drying wire (24) of the first wire group in the papermachine, most preferably the single wire pull group, seared with its front break roller (25), most preferably below this. Device according to any of claims 1-4, characterized in that the cover beam (30) of the device (100) is positioned to be supported by the guide pins (42) by the bearing support means (40) of the paper conduit roller (27) and the mutual position of the paper guide roller (27) and each other case bar (30) is maintained unchanged regardless of transfers in the position of the paper guide roller (27). 10 6. Apparatus according to any of claims 1-4, characterized in that on the side of the paper guide roller (27) located on the side of the paper sleeve (27) of said closure parts (32a, 39a) there is a protective part of soft material such as felt, gununi, plastic, electricity. like. 15 Device according to any one of claims 1-6, characterized in that the closing space (T) of said cover (30) is extended on the cylinder jacket of the paper guide roll (27) over a sector a ~ 60® - 150®, most preferably a = 90 °. 20 Device according to any one of claims 1-7, characterized in that said cover (30) comprises closed end portions (31a, 31b) and closed cover portions (K2.K2.K3) between them, which are most preferably of triangular cross-section and which are limited to each other. to the outer walls; 25 (33, 34) of the casing beam and whose inner walls (35a, 35b) intersect the outlet air ducts (35; 37). Device according to any one of claims 1-8, characterized in that the outlet air duct (35) of the casing beam (30) is divided into 30 parts with several vertical and machine-directed partitions (36), that the intermediate walls (36) in part the cover beam (30) rigid and said air duct opening in the direction of travel of the paper web to the exit side of the cover beam (30). 10. Device according to any of claims 1-9, characterized in that said air ducts (37) are connected by means of a trachea (38) with a source of vacuum (VAC), with which one can promote the air discharge from the closed outlet (T). ) of the case beam (30). Device according to any one of claims 1-10, characterized in that the lower wall (34) of said cover (30) limits a narrow air duct (C) together with the later articulated roller (23) of the press felt ( 20) of the separate nip (N *). t • · · * 4