FI69664C - INLOPPSLAODA FOER EN PAPPERSMASKIN - Google Patents

Description

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(51) Kv.1k. * / Lnt.CI. * D 21 F 1/02 (21) Patent application - Patentansökning ®® ^ (22) Application date - Ansökningsdag 1 1.04.80 (FI) (23) Starting date - Giltighetsdag 11. 04.80 (41) Made public - Blivit offentlig 1 2.1 0 .81

National Board of Patents and Registration Date of publication and month of publication. - 29.11.85

Patent- and registration registers '' Ansökan utlagd och utl.skriften publicerad (32) (33) (31) Requested privilege — Begärd priority (71) Valmet Oy, Punanotkonkatu 2, 00130 Helsinki 13, Finland-Finland (Fl) (72) Alvi Kirjavainen, Jyväskylä, Finland-Finland (FI) (74) Forssen & Salomaa Oy (54) Paper machine headbox - Inloppsläda för en pappersmaskin

The invention relates to a multilayer pulp box of a paper machine or the like having two or more pulp flow channels with turbulent generators through which one or more types of pulp suspension are fed through a lip gap or slots to a web-forming device having a separate headbox from a pulp suspension feed block, each connected to its own turbulence generator.

Multilayer headboxes are used, for example, in the manufacture of cartons and tissue paper. In this case, the web to be produced is formed of two or more pulp grades, which are fed to the forming part of the paper machine by means of a multilayer headbox or separate headboxes.

Although the headbox of the present invention is primarily intended for the manufacture of webs consisting of several 69664 different grades of pulp from which a web-forming pulp jet is composed, it should be emphasized that the invention also includes headboxes using only one pulp grade which is derived at least at the beginning of the flow paths for two different paths for later survival purposes.

With regard to the state of the art related to the invention, reference is made as one example to FI patent No. 27191, which discloses a headbox structure with a separator tongue inside the lip cone, which divides the lip cone into two parts. Said two parts are connected to the feed channels of different masses.

With regard to the state of the art closely related to the present invention, reference is made to the applicant's FI patent application No. 800018 (January 2, 1980). This application discloses a turbulence generator for a paper machine or similar headbox with a plurality of parallel flow cells which provide turbulence to the pulp suspension flowing through these cells. What is essentially new in the turbulence generator of the reference application is that the turbulence generator consists of a plurality of parallel, preferably identical, sub-elements arranged between the walls of the headbox, said sub-elements being shaped so as to form and / or at least partially interspersed with them. The multilayer headbox according to the present invention utilizes the turbulence generator of said FI application in such a way as to provide new practically important advantages.

However, a disadvantage of the previously known multilayer headboxes has been that a new headbox has had to be purchased as the production quality of the paper machine has changed, because the known headboxes have been fixed in construction and have no possibility of modification. However, the price of a headbox is several million marks, and thus a change or substantial conversion of production quality entails considerable costs and long production downtimes. It has also not been possible in previously known headboxes to adjust the headbox structure and the resulting properties optimally when different production parameters vary, as such adjustments would require very expensive and permanent structural changes in known fixed headbox structures.

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The object of the present invention is to provide a multilayer headbox which can be easily and quickly modified to the desired production quality and / or adjustable to its optimum in various properties. It is a further object of the invention to provide a multilayer headbox whose number of mass layers can be varied, i.e. to be increased and decreased whenever necessary. It is a further object of the invention to provide a headbox which can be modified in its essential parts, including the parts of turbulence generators, so that the structure of the headbox can be adjusted quickly and at relatively low cost with sufficient precision to meet the specific requirements of each production quality and production condition.

In order to achieve these and later objects, the invention is essentially characterized in that said turbulence generators consist of a plurality of separate flow elements delimiting parallel flow cells between and / or inside them, arranged between the headbox and its sub-blocks, and the turbulence generators of the separate supply blocks are interchangeable according to the production qualities without substantial changes in the fixed structures.

In a preferred embodiment of the invention, a multilayer headbox with a turbulence generator and a separate block divider 11a is realized, in which the block divider is symmetrically opposed to the flow up to the lip cone, whereby the flow disturbances affecting the cross-section in the manifold are partially compensated. The invention makes the structure of the headbox cheap, because in principle, for example, only the spacer at one end, diluted obliquely at its end, divides the 1-layer headbox into two parts.

The cassette-like easily modifiable structure according to the invention can be adapted to the flow rate, consistency, mass quality and the desired level of turbulence. Turbulence generator cartridges can be added or decreased, changed to another when the production quality changes decisively. With said measures, it is possible to modify new headboards with 1,2,3 etc. layers as desired, depending on the intended use in each case. In a preferred embodiment of the invention, the upper and lower body halves of the turbulence generator cassette are dimensioned to be completely symmetrical, so that they can form a desired number of generator cassettes with exactly the same locking shoulders and mating surfaces, regardless of the flow cross-sectional height of each cassette.

The present invention utilizes the advantageous features of the invention of said FI patent application No. 800018 in such a way that new advantages are provided. The invention of said FI patent application makes it possible that the block and cassette structure of the headbox according to the present invention also involves fast and easy assembly and disassembly of the turbulence generators used in the sub-blocks, as well as interchangeability and adjustability according to the respective production quality and other headbox structure.

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.

Figure 1 shows a side view of a two-ply headbox according to the invention, which is intended mainly as a headbox for a tissue paper machine.

Fig. 2 shows a three-layer headbox in a manner similar to Fig. 1, the number of layers of which, however, can be varied relatively freely.

Figure 3 shows a two-layer headbox solution according to the invention in a manner corresponding to Figures 1 and 2.

Figure 4 shows a section IV-IV in Figure 1.

Fig. 5 shows a structural solution of the turbulence generator and Fig. 5 is at the same time a section V-V in Fig. 2.

Fig. 6 shows a structural solution of a turbulence generator, and Fig. 6 is at the same time a section VI-VI in Fig. 3.

Figure 7 is a section VII-VII in Figure 3.

The lip gap L of the headbox is arranged in the vicinity of the feed crystal G formed in connection with the breast rollers 10 and 13. Said gap G is bounded between wires 11 and 14 or similar fabrics guided over rollers 10 and 13. With the headbox according to the invention 5 69664, the pulp or different pulps are fed between the wires 11 and 14, where the formation of the web W takes place from the two-wire formers in a manner known per se. Although the invention will now be described with reference to embodiments using a double-wire former, it will be appreciated that the headbox of the invention may in some cases also be used in single-wire formers or single-wire formers, usually relatively short, followed by a double-wire forming area.

The lower lip beam 20 of the headbox structure rests on the support beams 15 via the articulated shafts 17 and 18. The lower lip structure 20 has an upper wall 20 'which contributes to limiting the flow channel of the pulp suspension. The lower lip structure 20 is adjustable in position. For this purpose, a movable carriage 16 is arranged in connection with the PTO shaft 17 in the guide 17 ', which is moved by a screw and a gear 16'. Correspondingly, the lower lip structure 20 is supported at its lower end by a support lug 18 'which is attached to the end of the lower lip structure 20 by means of a guide 19. Between the support lug 18 'and the lower lip structure 20 is a screw which is driven by the gear 19'. The support lug 18 'is attached by a pivot shaft 18 to structures supported by a guide 17' on the headbox support beam 15. The lower lip structure 20 can be moved in the directions of arrows A and B by the devices described above, thus providing the lower lip structure 20 and its upper wall 20 '.

The headbox includes an upper wall structure 32,33 consisting of a beam 33 to which an upper lip beam 32 is connected by a joint 31. The housing of the joint 31 is bounded between the pieces 29 and 30. The piece 29 is fixed to the end flange 28 of the beam 23 forming the top wall of the headbox. The lip plate 36 is adjustable by a plurality of parallel screws 35 which are rotated by means of handles 34 by means of handwheels 37. In this way the lip gap L is fine-tuned. The upper lip structure 32,33 is pivoted around its joints 31 by screws driven by gears 38. Said screws and gears 38 are connected by articulated shafts 39 and 39 'to the beam 33 and between the headbox top cover structures.

According to the invention, the headbox manifold consists of several overlapping blocks. According to Figures 1 and 4, these blocks are two on top of each other, namely blocks 21 and 22 separated by a partition 24. The flow channels of the manifolds delimited within blocks 21 6 69664 and 22 and the flow directions F. and F, opposite each other. Figure 4 shows the entry of the pulp into the flow channel K. illustrated by F1. and delete with arrow F.. The flows corresponding to 1 Iin J r lout in the channel K »are indicated by the arrows F„. and F „2} 2m J 2out

An essential feature of the bilayer box according to Figures 1 and 4 is the block manifold 21,22 described above, which is formed by symmetrically opposite blocks with separate inlet and bypass flows. In this case, a symmetrical and uniform flow distribution with respect to the transverse profile is achieved, because the flow disturbances of the opposite block are partially compensated in the final lip cone flow. An important component in Figures 1 and 4 is also the turbulence generators 40a and 40b, in which the tortuous flow slots S 1 are formed, which form intermittently expanding flow-changing and vortex-generating mating surfaces. At the end of the slots, where the lip cone region begins, there are tail vanes 71a in directions symmetrically opposite to the vanes 71b of the second block. The vortices of the impact surfaces of the periodically expanding soles Sj, as well as the cross-flow formed by the above-mentioned tail vanes 71a, 71b, effectively equalize the pressure pulses, disperse the fiber bundles and the clouds, which promotes good paper base formation.

As shown in Figures 1 and 4, the turbulence generators 40a and 40b consist of, for example, plastic molded part elements 71, of which only one type is required. Said cross-flows are achieved by placing the sub-elements in the overlapping turbulence generators 40a, 40b on opposite sides. The sub-elements 71 are provided with loose holes through which the sub-elements are supported by bolts 70 between the headbox walls 20 'and 23. Blocks 21 and 22 are supported by structures 25 and 26, between which at 27 the partition wall 24 of the blocks is supported. The septum 24 has a tapered tip portion 24 ', followed by a tapered lip cone portion S 1 terminating in a lip opening L.

According to Figure 2, the headbox comprises three separate feed blocks 121, 122 and 123 arranged between the walls 20 'and 55, each of which communicates with its own turbulence generator 41, 42 and 43. After these turbulence generators 41, 42, 43 there are flow channels S separated by the vanes 56, 57, ., li which terminate in the sharp edges 56 ', 57' of the downwardly converging vanes 56, immediately followed by a lip cone section.

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In the 3-layer headbox shown in Figure 2, the turbulence generators 41,42,43 consist of separate entities, the so-called cassettes, which can be used to form a turbulence generator operating in the 1,2,3 etc. layer as various entities and layer groupings according to the factors influencing the speed, mass quality, basis weight and other production quality. What is essential in this structure is that certain basic unit parts can be used to assemble different functional units for very wide-ranging production purposes, which means that when a decisive change in production quality does not have to be a completely new headbox. This is a significant problem today if the exceptional quality is in production only for a certain period.

The turbulence generators 41, 42, 43, the cassettes, the structure of which is shown in Fig. 2, consist of upper and lower parts 20 ', 51, 52, 53 and 54, 55, between which there is e.g. a turbulence part according to Fig. 5.

In Fig. 2, the lower part of the lowest turbulence generator cassette 41 is formed by a lower lip wall 20 ', the upper part of which is connected at the front and rear by locking shoulders 61 and 64. joint estate. The mounting end of the middle generator cassette 42 is similar to the previous one. Essential to the design in terms of force control is precisely that the generator cartridges 41,42,43 can be added and decreased, with the articulated housing 58 and the rear shoulders 61,62,63 acting as a precise lock in each option.

On top of the wall 55 of the upper generator cassette 43 is an upper lip support beam 23 with a joint 31 of the upper lip 32 and a drive pad. It is characterized in this construction that the locking shoulder 66 in front of the support beam 23 corresponds exactly to the dimension of the articulated housing half, whereby the support beam 23 with the upper lip 32 can be easily locked to any shoulder lock of the 1,2,3 etc. layer option. At the rear, the corresponding shoulder locking 63 takes place relative to the support beam 23 by a locking rail 63 '.

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The intermediate lip plates 56,57 located in the lip cone are articulated to the above-mentioned joint housings by shaft pins 58 extending through the side walls, with which the position and "floating" operating position of the lip plate 56.57 are adjusted. The structure of the hollow sheet, preferably made of Teflon-coated aluminum, reinforced plastic or the like, has been sought to be such that its bulk density is substantially equal.

Fig. 3 shows a multilayer headbox, the construction of which is essentially, as in the solution of Fig. 2, a turbulence generator 141,143 and 142,144 operating in a layer 1,2,3, etc., cassettes in which the flow control and turbulence elements are e.g. turbulence vanes 73 as in Figs. , 74. An exception to the implementation of Figure 3 compared to the previous one is that the flow generation cycles are the same as in the SYM-NOZZLE (trademark) headboxes currently used by the applicant, and also that flow generating elements of similar function can be applied to the structure, e.g. flute, compensating chamber, lamella part or corresponding. Thus, after the manifold block 131, the lower cassette portion has a portion 141 corresponding to the whistle portion, followed by a compensating chamber portion and then a turbulence portion 143 corresponding to the lamella portion. ', Between 51.52 and 53.

The turbulence impeller 72 of Figure 5 is used primarily in the turbulence generator 41,42,43 of Figure 2. The flow gate of Fig. 5 is formed by a flow directing section starting from the manifold side, the function of which is to reverse the transverse manifold flow in the direction of the machine. This is followed by a tortuous and periodically expanding compensating part, the collision surfaces of which and the change of flow direction with their turbulence effectively equalize the pressure pulses and disperse the fiber bundles and clouds. In the wider flow channel in the direction of the machine, the final direction of flow is stabilized, and the actual level and shape of turbulence required to form the paper base is determined by the vertical and horizontal tail vanes at the downstream end.

The flow control vane 73 according to Fig. 6 is more straightforward and simpler in structure, since its main function is to direct the manifold flow of Fig. 3 parallel to the machine with its solstice S ^ ".

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The turbulence vane 74 shown in Fig. 7 consists of vertical and horizontal projections which taper gradually after the collision surface on the side of the equalization chamber and terminate in a so-called tail wing parts. Essential to the previously described structures is that the flow pattern on the equalization chamber side has horizontal projections transversely to the vertical, the width dimensioning of which provides an open flow cross-section corresponding to the optimum velocity and the best possible turbulence vane distribution. The flow resistance of the impact surface effectively compensates for the flow disturbances in the equalization chamber. In the stepwise expanding flow system S ^ ', successive eddy zones are created, which reach a fine and small-period microturbulence level in the final tail wing section, which enables the formation of a uniform paper base.

Figures 4,5,6 and 7 show only some structural examples of the sub-elements of the turbulence generator. It is to be understood that within the scope of the invention, the structure of these sub-elements may differ greatly from those shown in the above figures. For example, all the sub-elements presented in the applicant's FI patent application No. 800018 or other sub-elements suitable for the respective application can be used.

In a preferred embodiment of the invention, for example in Figure 2, the overlapping cassette headbox blocks 121, 41, 122, 42, 123, 43 form parallel flow channels of the pulp suspension, the main flow directions of which are so radial to each other that the planes of the main flow directions substantially intersect at the lip gap L.

Although paper machines have been discussed in general above, of course the headbox according to the invention can also be used in other similar machines, such as carton machines.

The following are claims within the scope of which the various details of the invention may vary within the scope of the inventive idea.

Claims (7)

10 6 9 6 6 4 A multilayer headbox of a paper machine or the like having two or more pulp flow channels with turbulence generators through which one or more types of pulp suspension are fed through a lip gap (L) or slots 21 to a web-forming device , 22; 121,122, 123; 131,132), each connected to its own turbulence generator (40a; 40b; 41,42,43; 141,142,143,144), characterized in that said turbulence generators consist of a plurality of parallel flow cells (S1 ^; S ^; S ^) separate sub-elements (71; 72; 73,74) delimiting between and / or within them, arranged between the substantially planar walls (20 ', 23,24; 20', 31,52; 53 »54,55) of the headbox and its sub-blocks and that the headbox is cassette-structured (Figure 1) such that the number of separate feed blocks and the turbulence generators of the separate feed blocks markets are interchangeable according to production qualities without significant changes in fixed structures. Headbox of a paper machine or the like according to claim 1, characterized in that the flow channel of the lower sub-block of the headbox is limited to the upper wall (20 ') of the lower lip structure (20) of the headbox, preferably adjustable in position, and that the upper wall of the upper sub-block ). Headbox according to Claim 1 or 2, characterized in that the headbox has two overlapping sub-blocks separated by a partition wall (24) extending between the manifold blocks (21, 22) and the turbulence generator blocks (40a, 40b) in the region of the converging lip cone of the headbox. . Headbox according to Claim 1, 2 or 3, characterized in that the flow directions (F ^ .F ^) in the immediately overlapping manifold blocks are opposite to one another. A headbox for a paper machine or the like according to claim 1, 2, 3 or 4, characterized in that each manifold block and / or turbulence generator block has its own bottom wall and cover wall and in that said walls or at least a part thereof are connected by groove projections acting as quick connectors. fittings (61,62,63,64,65,66) or the like into a single headbox assembly. Headbox of a paper machine or the like according to claim 1,2,3,4 or 5, characterized in that, after the turbulence generators, the parallel pulp suspension flow channels are separated by one or more lip plates (56, 57) articulated at their front ends to the headbox structures and preferably converging towards the lip opening (L) and having a bulk density substantially equal to the bulk density of the pulp suspension. Headbox according to claim 1, 2, 3, 4, 5 or 6, characterized in that the main directions of the flow channels of the overlapping cassette blocks of the headbox are so radially arranged that the radial planes set through said main directions intersect in the area of the headbox lip (L) . __ - ΊΓ. 12 6 9 6 6 4