Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
  • D21F1/02—Head boxes of Fourdrinier machines
  • D21F1/022—Means for injecting material into flow within the headbox
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
  • D21F1/02—Head boxes of Fourdrinier machines
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
  • D21F1/02—Head boxes of Fourdrinier machines
  • D21F1/026—Details of the turbulence section

Definitions

• the present invention relates to a method according to the preamble of claim 1 for arranging edge feed in connection with the headbox of a fibrous web machine.
• the present invention also relates to an apparatus according to the preamble of claim 7 for arranging edge feed in connection with the headbox of a fibrous web machine.
• the purpose of the present invention is to improve the state of the art of the field by disclosing such a method and an apparatus for arranging an edge feed in connection with the headbox of a fibrous web machine by means of which the prior art problems can be minimized.
• the aim of the present invention is to provide a method and an apparatus by means of which it is easy to, fast and simple to modemize prior art headboxes and to bring them to a level on which they can fulfil the requirements placed by the customers of the paper mill to the paper.
• the advantages of the present invention are mainly making the modernization of the headbox faster and simpler. These advantages are achieved by bringing the edge feed flow into the headbox in a new way by using a nozzle attached to the end cover of the intermediate chamber of the headbox the nozzle directing the flow of the fibrous pulp past the nozzle and combining the edge feed flow with the flow of fibrous pulp downstream of the nozzle.
• the advantage of such a nozzle is its easy installation into existing headboxes, simple construction and thus its cost-efficiency.
• the design of the nozzle is such that the edge feed flow is combined with the fibrous pulp flow without interference.
• the end cover of the intermediate chamber is provided with a lid that can be removed from the headbox and to which said nozzle can be fastened relatively easily.
• figure 1 is a general cross-sectional view of a headbox of a fibrous web machine
• figure 2 is a partially sectional and transparent perspective view of a headbox modernized according to a first preferred embodiment of the present invention
• figure 3 is a partially sectional and transparent view of a headbox according to figure 2 and the as yet uninstalled edge feed limiting plate beside it
• figure 4 is a partially sectional and transparent view of a headbox according to figure 2 and the as yet uninstalled edge feed limiting plate of another type beside it,
• figure 5 shows the headbox of figure 2 seen from behind and above
• figure 6 shows the headbox of figure 2 seen directly from the side
• figure 7 shows a headbox modernized according to a second preferred embodiment of the invention, into which the edge feed according to the invention is arranged by means of a special nozzle, and
• figure 8 shows the headbox of figure 7 seen from above.
• the holed plate 17 being a part of the turbulence generator and being the first in the pulp suspension introduction direction is preceded by an intermediate chamber 18, above which this headbox comprises a dampening chamber 18a being in connection with the intermediate chamber and equalizing the pressure pulsations of the pulp flow.
• the holed plate 17 acts as the rear wall of the intermediate chamber.
• the pulp suspension flow is introduced from the bypass manifold 20 via the manifold pipeline 19 to the intermediate chamber 18.
• Figure 2 shows a headbox solution according to a preferred embodiment of the invention as partially sectional and transparent perspective view.
• the figure illustrates the turbulence generator 16, intermediate chamber 18 and the holed plate 17 acting as its rear wall, dampening chamber 18a and the manifold pipeline 19 already shown in the previous figure.
• the figure additionally shows, with the reference numeral 20, the front wall on the side of the manifold pipeline 19 of the intermediate chamber 18, the wall being provided with feed holes 21 for allowing the pulp suspension from the manifold pipeline 19 to enter the intermediate chamber 18.
• the fibrous pulp is introduced via the manifold pipeline 19 to the intermediate chamber 18 and therefrom to the slice channel via the turbulence generator 16.
• the intermediate chamber 18 is provided with a limiter plate 30 (with only the closer limiter plate shown in figure 2) being located in the embodiment 30 to 150 mm from the end of the intermediate chamber 18 to between the front wall 20 of the intermediate chamber 18 and the holed plate 17 acting as the rear wall so as to be closely against the bottom and top of the intermediate chamber 18.
• the said limiter plates 30 separate special edge feed chambers 18b (shown in figure 5) to both ends of the intermediate chamber 18 transverse in relation to machine direction.
• the installation of the limiter plates 30 is carried out simply by opening the lids 22 (lid shown removed) at the ends of the intermediate chamber 18, by passing the limiter plates 30 inside through the formed openings and by turning or fastening them to their places.
• edge feed is arranged into the edge feed chambers 18b (figure 5) between the limiter plates 30 and the end lids 22 of the intermediate chamber 18 by means of conduits fastened to the holes 23 bored to the lids 22 of the intermediate chamber 18, subsequent to which the edge feed is mixed with the fibrous pulp flow in the edge feed chamber 18b.
• the actual edge feed is preferably brought into the conduits by means of flexible rubber hoses, whereby opening of the end lids 22 of the intermediate chamber 18 is easy, when necessary.
• the direction of the edge feed can be chosen as desired, i.e. it can either be directly in the longitudinal direction of the intermediate chamber, i.e.
• the edge feed can also be introduced in addition to the horizontal level also tilted in the direction of either the bottom or top of the intermediate chamber.
• the adjustment possibilities available with the edge feed can be enhanced by arranging a throttling to at least a part of the manifold portion, i.e. some of the pipes of the edge area of the manifold pipeline 19 or their feed openings 21 in the wall 20.
• the flow of the edge area can also be reduced in comparison with the constant flow arriving in the said manifold pipeline.
• the said throttling is easy to arrange simultaneously with installation of the limiter plate 30 by, for example, by fastening a throttle plate to the front wall 20 of the intermediate chamber, at least some of the openings of the plate being smaller then the feed openings 21 of the pipes of the manifold pipeline 19 in the front wall 20. It is additionally possible to reduce, together with the throttling of the manifold pipeline or separately, the flow resistance of the pipes of the turbulence generator 16 opening into the edge feed chambers 18b, thus reducing the pressure loss of the turbulence generator 16 in said edge areas, whereby it is possible to increase the flow rate. This can be carried out by generally increasing the diameter of the turbulence generator, i.e.
• Figure 3 illustrates practically the same headbox solution as figure 2.
• the limiter plate 30 has been removed from the intermediate chamber 18 and shown at the side of the headbox.
• the limiter plate 30 consists of the actual plate portion 32 and at least one bracket 34 arranged at one side thereof for fastening the plate to inside the intermediate chamber.
• the plate portion 32 is intentionally bent or twisted so that at its ends it is on one hand located between the pipes of the manifold pipeline 19 and on the other hand between the pipes of the turbulence generator 16 on the isthmuses between the pipes without affecting the flow from the pipes of the manifold pipeline 19 to the edge feed chamber or from the edge feed chamber to the pipes of the turbulence generator 16.
• the shape of the plate part can, in addition to being straight, be also curved, twisted (figures 2 to 5) or wave-like.
• the bracket 34 shown in the figure is positioned, when the limiter plate 30 is installed in the intermediate chamber 18, preferably to the opening 25 between the intermediate chamber 18 and the dampener chamber 18a, thus closing the flow connection from the edge feed chambers separated by means of limiter plates 30 at the ends of the intermediate chamber 18 to the dampening chamber 18a.
• the bracket is additionally formed so that the actual mechanical fastening of the limiter plate 30 is carried out directly into the end of the intermediate chamber 18, i.e. either to the end lid 22 of the intermediate chamber or to the part of the end possibly remaining beside it. This is most easily carried out so that a threaded hole is arranged in the bracket 34, to which the fastening screw can be threaded via a hole drilled into the end/lid 22 of the intermediate chamber.
• Figure 4 illustrates further the otherwise same headbox solution as in figure 2 but here there is an alternative limiter plate 40 on the side of the headbox.
• the limiter plate 40 is formed by a plate part 42 and a bracket 44, and the characterizing features disclosed in connection with the previous figure apply here as well.
• this embodiment shows how at least three edges of the plate part 42 are provided with edge plates so that the side plates 46' and 46" are located against the top and bottom of the intermediate chamber 18 and the side plate 48 is located against the front wall 20 of the intermediate chamber 18.
• the limiter plate can be fastened with screws/bolts by its side plates 46', 46" and 48 to the top and bottom and the front wall 20 of the intermediate chamber 18 in addition to the bracket 44.
• the fastening takes place from the side of the edge feed chambers, i.e. between the limiter plate 40 and the end of the intermediate chamber 18.
• the above-mentioned bracket 44 is not necessarily needed at all for fastening, but only to close the opening 25 between the edge feed chamber and the dampening chamber 18a.
• a side plate 48 arranged in the first end edge of the limiter plate 40, located abutting against the front wall 20 of the edge feed chamber, is provided with openings facing the feed openings 21 of the manifold pipeline 19 (shown in figure 2), allowing, depending on its size, either full flow from the said openings 21 or throttling the flow therein.
• the throttling described above can be easily carried out by using the same limiter plate 40 used for arranging the edge feed.
• the limiter plate 40 can, in addition to the other fastening points mentioned above, be also fastened to the holed plate 17 of the intermediate chamber 18 in the side of the turbulence element 16 similar to other sides of the limiter plates by using a side plate. It is also possible not to make some actual fastenings and to ensure the sealing of the edge feed chamber with sealing putty between the side plates/bracket of the limiter plate and the wall/s of the intermediate chamber 18.
• Figure 5 illustrates the intermediate chamber solution shown in figure 2 seen from above and behind so that a limiter plate 30 is arranged near one (right) end of the intermediate chamber 18, the plate separating an edge feed chamber 18b to the right side thereof.
• the figure shows especially clearly the curving of the limiter plate 30 so that the plate 30 is vertical in the end facing the pipes on top of each other of the manifold pipeline 19 and on the opposite end curved due to the interlaced pipes of the turbulence element 16 so that the plate 30 is located onto the isthmuses between the pipes 16 without affecting the flow into the pipes.
• the limiter plate is correspondingly located on the isthmus between the pipes of the manifold pipeline 19.
• Naturally some other kind of location of the pipes of the manifold pipes and/or the pipes of the turbulence element requires corresponding changes into the position or shape of the limiter plate as well, whereby the limiter plate can also be straight, curved or wave-like.
• Figure 6 illustrates the intermediate chamber solution according to the present invention as shown in figures 2 and 5 seen from the side so that a limiter plate 30 is provided near one (right) end of the intermediate chamber.
• Figure 6 shows clearly that the bracket 34 of the limiter plate 30 tightly seals the flow opening between the intermediate chamber 18 and the dampening chamber 18a. This is essential, because the operation of the edge feed requires that the pressure of the edge feed chamber must be regulated in comparison with the other intermediate chamber. Thereby the limiter plate must be closely against all wall surfaces of the intermediate chamber.
• the limiter plate according to the above disclosure can also be used when modernizing a headbox where there is no dampening chamber but the upper surface of the intermediate chamber is totally enclosed. In this situation, similar to models having a dampening chamber, the edge feed chamber must be sealingly separated from the rest of the intermediate chamber to arrange the desired pressure difference between them.
• FIG. 7 and 8 show how the lid or cover 22 covering the ends of the intermediate chamber is provided with a nozzle 50 by means of which the fibrous pulp edge flow from the manifold pipe via the valve is directed so as to be in machine direction.
• the nozzle comprises an actual nozzle part 52 turning the flow and a feed pipe 54 fastened in the bottom thereof and extending through a hole 23 arranged in the end lid 22 of the intermediate chamber to outside the headbox so that a pipe, preferably a flexible rubber hose, can be fastened to the pipe 54.
• the nozzle part 52 can comprise e.g. a bottom part located against the end lid 22 of the intermediate chamber, preferably side plates positioned in machine- directional level and a preferably curved lid plate directing the flow in machine direction as desired.
• the nozzle opening of the nozzle 50 is located downstream from the feed pipe 54 of the nozzle 50.
• the nozzle 50 is fastened by its bottom part to the end lid 22 of the intermediate chamber.
• Another alternative is, naturally, to fasten the nozzle directly to the end lid 22 of the intermediate chamber and to arrange a conduit in connection with the hole 23 of the end lid 22 to which the pipe carrying the edge feed flow can be fastened. It can further be considered that the side plates of the nozzle are curved as well as the cover lid.
• the edge feed flow is mixed with the fibrous pulp flow subsequent to the nozzle 50 before the holed plate 17 of the turbulence generator 16.
• the outlet end of the nozzle 50 is located near the holed plate 17, preferably the distance from the outlet end and the holed plate 17 is from 1 to 150 mm in order to direct the edge feed flow to the edge area only.
• the edge feed according to the invention can be arranged in both headboxes having separate edge feed chambers in the opposite ends of the intermediate chamber, as is shown in figures 2 to 6, and to headboxes in which the intermediate chamber is one continuous space.
• the nozzle solution of figures 7 and 8 can also be used in headboxes having edge feed chambers and the solution of figure 2 can be used in headboxes without edge feed chambers.

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Citations (4)

• 2010
  • 2010-04-29 FI FI20105467A patent/FI20105467A/fi not_active IP Right Cessation
• 2011
  • 2011-04-26 WO PCT/FI2011/050371 patent/WO2011135176A1/en active Application Filing

Patent Citations (4)

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