EP0770727A1 - Verfahren und Vorrichtung zur Entwässerung einer Papierbahn durch Pressen - Google Patents

Verfahren und Vorrichtung zur Entwässerung einer Papierbahn durch Pressen Download PDF

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Publication number
EP0770727A1
EP0770727A1 EP96120948A EP96120948A EP0770727A1 EP 0770727 A1 EP0770727 A1 EP 0770727A1 EP 96120948 A EP96120948 A EP 96120948A EP 96120948 A EP96120948 A EP 96120948A EP 0770727 A1 EP0770727 A1 EP 0770727A1
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EP
European Patent Office
Prior art keywords
web
press
roll
fabric
nip
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP96120948A
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English (en)
French (fr)
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EP0770727B1 (de
Inventor
Juhani Pajula
Martti Hirsimäki
Juha Kivimaa
Pekka Taskinen
Jorma Laapotti
Mikko Karvinen
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Metso Paper Oy
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Valmet Oy
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Publication of EP0770727A1 publication Critical patent/EP0770727A1/de
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D21F3/0209—Wet presses with extended press nip
    • D21F3/0218—Shoe presses
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D21F3/04—Arrangements thereof
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D21F3/04—Arrangements thereof
    • D21F3/045—Arrangements thereof including at least one extended press nip

Definitions

  • the invention concerns a method in the manufacture of paper or board for dewatering of the paper web that is being manufactured and that has been drained in the former of the paper machine, in which method the dewatering yes place by passing the paper web on support of fabrics that receive water through a number of subsequent dewatering nips so that, by the effect of the compression pressure, water is transferred out of the fibre mesh of the paper web into the spaces in the fabric that receives water as well as into the spaces in the hollow faces of the mobile dewatering members, such as press rolls.
  • the invention concerns a press section of a paper machine, into which the paper web to be dewatered by pressing is passed from the former of the paper machine and from which the paper web is passed into the drying section of the paper machine, which press section comprises at least two separate press-nip zones, two press fabrics that receive water passing through at least the first one of said press-nip zones, between which fabrics the web runs through said nip zone.
  • the structure of paper in particular of printing paper, must also be symmetric.
  • the good printing properties required from printing paper mean good smoothness, evenness and certain absorption properties at both faces.
  • the properties of paper, in particular the symmetry of density, are affected considerably by the operation of the press section in a paper machine, which has also a decisive significance for the evenness of the transverse profiles and longitudinal profiles of the paper.
  • Dewatering by means of pressing is energy-economically preferable to dewatering by evaporation. This is why attempts should be made to remove a maximum proportion of water out of a paper web by pressing in order that the proportion of water that must be removed by evaporation could be made as low as possible.
  • the increased running speeds of paper machines provide new, so far unsolved problems expressly in the dewatering taking place by pressing, because the press impulse cannot be increased sufficiently by the means known in prior art, above all because, at high speeds, the nip times remain unduly short and, on the other hand, the peak pressure of compression cannot be increased beyond a certain limit without destruction of the structure of the web.
  • the property profiles of the paper that is produced in the machine direction are also affected significantly by oscillations of the press section, the transverse variations of properties by the transverse profiles of the nip pressures in the press nips, and with increasing running speeds of the machine these profile problems tend to be increased remarkably.
  • the object of the present invention is to provide novel solutions for the problems discussed above so that the above drawbacks in prior art and the drawbacks that will come out later are substantially avoided.
  • An object of the invention is to provide a method for dewatering of a paper web by pressing at high speeds, in particular at speeds of about 25...40 m/s, so that the adjustability of the press section is versatile, the properties of quality of the web produced can be kept high, and the web is not subjected to excessive dynamic forces that produce breaks.
  • one of the aims is that the overall construction of the press section, in particular its flame construction, should be such that the replacement of press rolls and press fabrics can be accomplished quickly so as to minimize the standstill times.
  • the method of the invention is mainly characterized in that the method comprises a combination of the following steps:
  • the press section in accordance with the invention is mainly characterized in that the press section comprises a combination of:
  • the paper web is not passed through the press section on one press fabric, but, to guarantee an adequate dewatering capacity, an arrangement of fabrics is employed in which the web is transferred from the pick-up point on the first upper fabric through the first press zone, preferably an extended-nip zone, through which zone the first lower fabric runs, onto which the web is transferred after said nip zone, and from said first lower fabric the web is transferred onto the second upper fabric, which carries the web into the second nip zone, which consists of a roll nip or preferably of an extended-nip zone, after which the web is transferred onto the second lower fabric, which runs through said nip zone and carries the web on its upper face as a closed draw onto the drying wire or into the next nip zone.
  • the most important objective achieved by means of the invention is a satisfactory running quality of the paper machine even at speeds as high as about 30...40 m/s. This has been achieved because of a "linear" draw of the web and of a nip arrangement that provides sufficiently long nip times.
  • the closed draw in accordance with the invention has been accomplished so that one and the same fabric does not carry the web through the whole press zone, but in at least two subsequent press zones two pairs of press fabrics are employed, the web being transferred onto the first upper fabric at the pick-up point, and after the first nip zone the web is transferred from the first lower fabric onto the second upper fabric, and after the second nip zone on the second lower fabric onto the drying wire or into the next nip zone, whose lower fabric carries the web onto the drying wire as a closed draw.
  • the method and the press section in accordance with the invention are intended for use above all with thin paper qualities, whose grammage is lower than 120 g/m 2 and with which a closed draw of the web is indispensable at the high web speeds meant in the invention.
  • the invention also achieves a sufficiently cautious and gentle start of the dewatering, which is important because at high speeds the water contents in the web after the former also tend to be higher.
  • said "Sym-Belt Press” provides several advantages of synergism, of which should be mentioned that said press produces practically no oscillations at all, for which reason it is well suitable also for very high speeds, said press permits keeping of the nip loads at a sufficiently low level in particular in the initial part of the press section and makes it possible to keep the nip times at a reasonable level even at very high speeds (30...40 m/s).
  • a further essential feature of the invention is the use of two press fabrics and their joint operation so that the web is transferred from the pick-up point onto the first upper fabric, after the first nip zone onto the first lower fabric, from the first lower fabric by means of a transfer-suction roll or equivalent onto the second upper fabric, and on it further after the second nip zone onto the second lower fabric, on which the web is transferred as a closed draw onto the drying wire or into the next press zone, in whose connection there is a pair of press and transfer fabrics similar to those described above.
  • said "Sym-Belt Press” provides entirely novel possibilities to control and to regulate the distribution of the nip pressures in the extended-nip zone both in the machine direction and in the transverse direction. Further advantages include low power consumption, elimination of difficulties of oil treatment, reduced wear of the mantle of the hose roll, and reasonable dry solids content of the web even at high speeds (30...40 m/s).
  • US Patent No. 4,584,059 as well as to the applicant's FI Patent No. 66,932 and FI Patent Applications Nos. 892517 and 892518.
  • the invention is related to a press frame solution which is suitable expressly for its environment and which provides advantages of synergism, because of which press frame solution the press rolls and fabrics can be replaced relatively quickly, which, for its part, increases the overall degree of operation of the paper machine and the economy of the paper machine investment.
  • Figure 2 shows such a variation of a press section as shown in Fig. 1 in which, in the second "Sym-Belt" extended nip, a lower press and transfer fabric is also employed, which contributes to the formation of the closed draw to the drying section.
  • Figure 3 shows a variation of the invention in which two subsequent "Sym-Belt" extended nips are employed which operate in opposite directions, as compared with one another.
  • Figure 4 shows an embodiment of the invention in which the first nip is a "Sym-Belt" extended nip and the second nip a two-fabric roll nip.
  • Figure 5 shows an embodiment of the invention that has a high dewatering capacity and in which three subsequent press nips are employed, of which the first and the last nip are roll nips and the middle nip is a "Sym-Belt" extended nip.
  • Figure 6 shows an embodiment of the invention that is intended for particularly high speeds and in which the first nip operates as a so-called wire press, which is followed by an extended nip, and the last nip is a roll nip.
  • Figure 6A shows an alternative embodiment of a wire press.
  • Figure 6B shows a second alternative embodiment of a wire press.
  • Figure 6C shows a third alternative embodiment of a wire press.
  • Figure 7 shows a press solution mainly in accordance with Fig. 4 as provided with a frame construction particularly suitable in connection with the invention.
  • Figure 8 is a side view of a frame module applicable in the invention.
  • Figure 9 is a vertical sectional view along the line IX-IX in Fig. 8.
  • Figure 10 is an axonomethc, partly sectional view of a hose roll of a "Sym-Belt Press" applicable in the invention.
  • Figure 11 is an axonometric view of a press shoe that can be loaded and profiled in a versatile way and that is fitted inside the hose roll and employed in a press as shown in Fig. 10.
  • Figure 12 shows an alternative construction that accomplishes an extended nip and that is provided with a closed glide belt loop.
  • the press section comprises a first upper fabric 20 that receives water, onto which fabric the web W is transferred on the suction zone 21a of the pick-up roll 21 at the pick-up point P from the forming wire 10, whose return run starts from the wire drive roll 12.
  • the press has two subsequent press nips, which remove water from the web W efficiently and between which the web W has a fully closed draw so that it is constantly supported by a fabric.
  • both nips NP 1 and NP 2 are so-called extended nips, whose press zone is substantially longer than that in a normal sharp roll nip.
  • the more detailed embodiments of the extended nips will be returned to later, mainly in connection with the descriptions related to Figs. 10, 11 and 12.
  • the first nip NP 1 is an extended nip
  • the second nip a sharp roll nip N 2 formed between hollow-faced rolls.
  • all the nips may be provided with two press fabrics that receive water, so that the water is removed from them through both faces of the web W. It is also possible to use one or several transfer fabrics that do substantially not receive water, in stead of said press fabric.
  • the first upper fabric is guided by alignment, tensioning and guide rolls 22 and conditioned by conditioning devices 23.
  • the first extended nip NP 1 includes a lower fabric 30 that receives water, being guided by alignment, tensioning and guide rolls 32 and conditioned by conditioning devices 33.
  • the first extended nip NP 1 and so also the second extended nip NP 2 are accomplished in a "Sym-Belt Press" of the applicant, and the details of the construction of said press will be discussed later.
  • the construction of the press is such that the extended nip NP 1 is composed of a flexible hose mantle and of a backup roll.
  • the press section includes a second upper fabric 40, onto which the web W is transferred as a closed draw by means of the suction zone 41a of the suction roll 41. After the first nip NP 1 , it is ensured that the web W follows the first lower fabric 30 by means of a suction box 36 or a corresponding foil arrangement.
  • the second upper fabric 40 is guided by alignment, tensioning and guide rolls 42 and conditioned by conditioning devices 43.
  • the second extended nip NP 2 is also formed in connection with a hose roll 45, which is similar to the hose roll at the extended nip NP 1 .
  • the lower press member at the nip NP 2 is a smooth-faced 105' press roll 105, in connection with whose lower sector a doctor 107 operates, which doctors the web W o going to broke handling and the leader band to the broke handling arrangement placed below (not shown).
  • the smooth face 105' of the press roll 105 makes sure that, after the extended nip NP 2 , the web W follows the face 105' of the lower roll 105, from which it is detached by means of a transfer nip N S and is transferred on support of the drying wire 80, which is guided by the guide roll 81, to the drying section, of which the first heated drying cylinders 82 and leading cylinders 83 are shown in the figures.
  • Single-wire draw is employed at least in the first cylinder group in the drying section.
  • Fig. 2 differs from the press section shown in Fig. 1 in the respect that the second extended nip NP 2 is a two-fabric nip and includes a lower fabric 50, which is guided by the tensioning, alignment and guide rolls 52 and conditioned by the conditioning devices 53.
  • the extended nip NP 2 is formed between the upper hose roll 45, the press fabrics 40,50, and the lower, hollow-faced 155' press roll 155. After the extended nip NP 2 , it is ensured by means of a suction box 56 and/or by means of the surface properties of the fabric 50 that the web W follows the lower fabric 50.
  • the web W is transferred as a closed draw onto the drying wire 80 as aided by the suction zone 81a of the suction roll 81, and further in the drying section 82,83, at least at the beginning, as a single-wire draw.
  • Fig. 3 differs from the press section described above in relation to Fig. 2 in the respect that, in the second extended nip NP 2 , the hose roll 55 is placed underneath inside the loop of the press fabric 50, and the upper backup roll is a hollow-faced 145', adjustable-crown press roll 145, which is placed inside the loop of the second upper press fabric 40.
  • the web W is transferred after the second nip NP 2 on the lower fabric 50 to the transfer point S, where the suction zone 81a of the suction roll 81 is placed, by whose means the web W is transferred as a closed draw onto the drying wire 80.
  • the embodiment of the invention shown in Fig. 4 differs from those shown in Figs. 2 and 3 in the respect that the second nip N 2 is a roll nip provided with two press fabrics 40,50 and formed between two hollow-faced 145' and 155' press rolls 145,155, which are preferably adjustable-crown rolls.
  • Figs. 5 and 6 show an embodiment of the invention that is suitable for use at very high paper machine speeds, e.g. in a speed range of about 25...40 m/s, and, if necessary, also with relatively thick paper qualities.
  • the first press nip N 1 is a so-called wire press, and therein the first fabric 120 is a relatively loose wire-like press fabric, onto which the web W, which has a very high water content and low strength as yet, is transferred on the pick-up zone 21a of the pick-up roll 21 at the pick-up point P from the forming wire 10 proper.
  • the wire press nip N 1 is formed between two press rolls 125 and 35, both of which press rolls have very open hollow faces 125' and 35'.
  • the lower fabric 30 is a press fabric 30 that receives water, onto which fabric the web W is transferred after the nip N 1 by the effect of the adhesion and surface properties of the suction box 36 and/or of the press fabric 30. From the fabric 30, the web W is guided onto the face of the second upper press fabric 40 by means of the suction zone 41a of the suction roll 41 placed inside the loop of said fabric 40.
  • the second nip proper is an extended nip NP 2 , in which the upper press member consists of the hose roll 45 and the lower press member of the hollow-faced 55' press roll 55.
  • a press fabric 50 runs, on which the web W is transferred onto the third upper press fabric 60 on the suction zone 61a of the suction roll 61, and further into the third, sharp press nip N 3 , which is formed between hollow-faced 65' and 75' press rolls 65,75.
  • the web W follows the lower third fabric 70, which is guided by the tensioning, alignment and guide rolls 72 and conditioned by the conditioning devices 73. From the third lower fabric 70 the web W is detached at the transfer point S on the suction zone 81a of the suction roll 81, being transferred onto the drying wire 80, which carries the web W as a single-wire draw through the first drying group in the dryer.
  • Fig. 6 shows a version of the invention that differs from Fig. 5 in the respect that the first wire press nip N o is placed in connection with the wet wire 10 proper so that, before the wire 10 drive roll 12 and the pick-up point P, a suction roll 16 that is provided with an open face and with a suction zone 16a is placed inside the loop of the forming wire 10. Placed against the suction roll 16, there is a press roll 15, which operates inside the loop of the press wire 19, which is provided with a very open mantle face 15', and which is guided by the guide rolls 11. Through the wire press nip N o , a relatively open press fabric 19 runs, which receives water and is well permeable to water.
  • Fig. 6 shows a version of the invention that differs from Fig. 5 in the respect that the first wire press nip N o is placed in connection with the wet wire 10 proper so that, before the wire 10 drive roll 12 and the pick-up point P, a suction roll 16 that is provided
  • the roll 15 may be a hollow-faced 15' steel roll or any other hollow-faced roll of low-weight construction, e.g. a roll with a composite mantle.
  • the roll 16 is preferably a wire suction roll.
  • the roll may, however, also be some other hollow-faced roll, and in such a case the wire suction roll is placed after the roll 16 separately.
  • the wire W which has been pre-pressed in the wire press nip N o , is transferred at the pick-up point P onto the first upper press fabric 20 proper, which carries the web into the first extended nip NP 1 similar to that described above, and from said nip further, on the first lower fabric 30, with the aid of the suction zone 41a, onto the second upper fabric 40, which carries the web W into the two-fabric roll nip N 2 , from which the web W follows the second lower fabric 50 and is transferred on support of said fabric, at the transfer point S, from the suction zone 81a onto the drying wire 80.
  • the dry solids content k o of the web W before the wire press nip N o is of an order of 10 %, and in a press as shown in the figure, the dry solids content k 1 at the pick-up point P is of an order of 20 %.
  • Fig. 6A shows such a variation of the wire press nip as shown in Fig. 6 in which a wet wire 10 and two press fabrics 19 and 19A that operate at opposite sides of the wire 10 are employed.
  • the lower press fabric 19A at the nip N o is placed inside the wire 10 loop and is guided by the guide rolls 11A.
  • an extended nip NP o is used as the wire nip.
  • the construction of the nip NP o corresponds to those of the nips NP 1 and NP 2 , and it is formed between a hose roll 15A provided with a smooth or hollow-faced glide-belt mantle 201 and a suction roll 16.
  • the pressure in the extended-nip zone NP o is, as a rule, in the range of 0.5...3 MPa.
  • Fig. 6C shows a variation of the invention in which a belt-tensioned nip NH o is employed.
  • Said nip NH o is formed between a wet wire 10 and a press fabric 19B that run over a suction roll 16.
  • a smooth-faced or hollow-faced tensioning belt 19C is arranged, which is guided by the guide rolls 11C.
  • the length of the press zone a o is, as a rule, in the range of 100...500 mm.
  • the construction is similar to that described above in relation to Figs. 6, 6A and 6B.
  • the method in accordance with the invention can be carried out and the press section in accordance with the invention be constructed so that the only extended nip in the press section is exactly the extended nip NP o operating in connection with the wet wire 10 or some other, corresponding extended nip, in which case the rest of the nips in the press section are roll nips, for example relatively long roll nips between press rolls of relatively large diameters.
  • the web W has a closed and supported draw as it moves from the pick-up point P on the forming wire 10 to the point S, at which it is transferred onto the drying wire 80 of the drying section and further as a supported single-wire draw at least through the first drying group.
  • the fact that, after each nip, the web W follows the fabric that is supposed to carry it forwards is ensured by means of various suction or foil devices, covering angles of the press fabrics, and/or adhesion properties of the fabrics. Of these devices, the suction boxes 56 are shown in the figures.
  • the run of the web W to be pressed through the press section is highly linear without major curves. Owing to the linear path of the web, the dynamic forces applied to the web remain sufficiently low in view of minimizing the risk of breaks.
  • the magnitude of the angle a of change in the direction of the web W is in the range of a ⁇ 10...30° and, as a rule, a ⁇ 15°. An exception from this may be formed by the pick-up roll 21 and its suction zone, at which locally even a high negative pressure may be employed, as well as, in Fig. 1, by the smooth-faced 105' lower press roll 105 and its turning sector b.
  • a press geometry as shown in Fig. 1 is not preferable when the maximum speed range (30...40 m/s) of the applications of the invention is employed.
  • p max a relatively low peak pressure must be used in the first roll nip, in which the water content of the web is high: p max ⁇ 2.5...4 MPa.
  • the frame of the press consists of two substantially identical cantilevered press frame units 110, of which the first unit 110 is provided for the first extended-nip press NP 1 and the second unit for the latter extended-nip press NP 2 .
  • the press frame units 110 are placed one after the other on foundation constructions 110.
  • the foundation constructions 100 consist of horizontal beams 101 and vertical beams 102, which extend into the basement space KE.
  • the top sides of the beams 101 determine the floor level L of the paper machine hall.
  • the frame units 110 are quite closed, and they are placed at a relatively short open horizontal distance L o from one another.
  • the gap L o is placed at the point where the web W is transferred from the lower fabric 30 onto the upper fabric 40.
  • Fig. 7 shows a steam box 49, which is placed after the suction zone 41a of the suction roll 41 and by whose means the outer face of the web W is affected so that its temperature level is raised and, thereby, the dewatering is promoted in the nip N 2 by affecting the elastic properties of the web W and the viscosity of the water present in the web.
  • Fig. 7 further shows a part of the forward end of the hood 150 of the drying section.
  • the frame units 110 comprise vertical frame beams 116 at the driving side K of the paper machine and corresponding frame beams 117 at the operating side H.
  • the transverse cantilevered parts of the frame unit 110 consist of a lower horizontal beam 118a and upper horizontal beams 118b, of which latter beams there are two beams placed side by side, and of a horizontal upper beam 118c.
  • Said beams are supported on the vertical frame parts 117 at the operating side as well as on draw members 119a, 119b and 119c; by tensioning said draw members in a way in itself known, it is possible to support the horizontal beams 118a, 118b, 118c so that the intermediate pieces 112a,112b, 113a,113b, 114a,114b at the driving side K can be opened for replacement of the fabrics 20,30,40,50.
  • the frame units 110 are highly compact, however, so that replacements of the press fabrics and rolls can be carried out quite quickly.
  • the arrows V illustrate the guide rolls 20,30,40,50 of the various fabrics as shifted to inner positions to their parking sites so that the press fabrics 20,30,40,50 can be replaced as a smaller loop while the rest of the fabric loop has been wound onto replacement poles (not shown), so that the press fabrics are spread and tensioned into their positions afterwards.
  • the front part of the frame unit 110 is provided with a projection part 111, in connection with which the suction rolls 21 of the upper fabrics 20;40 as well as the foremost tensioning and guide rolls are mounted.
  • the side frames of the press sections shown in Figs. 7 and 8 are in such a way open that the press rolls can be replaced by pulling to the side, because replacement straight upwards is impossible because of the closed compact constructions of the press frames.
  • Replacements of the press fabrics 20,30,40 and 50 are carried out in a way known in prior art by making use of tensioning members 119a, 119b, 119c, by opening the intermediate pieces 112,113,114, and by shifting the outermost leading or tensioning rolls, which are placed inside the fabric loops and shown in Fig.
  • Fig. 6 the first frame construction, which has been modified to the necessary extent, is fitted in connection with the wire nip N o , whereas the other frame units 110, which are provided for the nips NP 1 and NP 2 , are similar to those described above in relation to Figs. 7,8 and 9.
  • the hose roll 200 comprises an elastic mantle 201, which is made, e.g., of fabric-reinforced polyurethane, so that the hose mantle 201 is made of rubber-like stretching material, whose maximum elongation is, e.g., about 20...40 %.
  • the thickness of the hose mantle 201 is, e.g., about 2...5 mm.
  • annular ends 202a and 202b are fixed permanently, the inner parts of said ends being fixed and sealed against revolving axle journals 207a and 207b, which are mounted on the frame parts 110 of the machine by means of fixed bearing supports.
  • the hose roll 200 includes a stationary inner frame 205, around which the hose mantle 201 with its ends 202a,202b revolves on the bearings 206a and 206b.
  • cylinder block sets 203 two sets side by side, are fitted in the inner frame 205.
  • hydraulic support members 206,207 of the glide shoe 210 operate, which members are, thus, placed in two rows, e.g., with a spacing of about 25 cm in the transverse direction one after the other.
  • the two rows of the hydraulic support members 206,207 support a support plate 209, to which a glide shoe 210, e.g., of aluminium is attached, in whose area an extended nip zone NP is formed against a backup roll.
  • the glide shoe 210 is provided with a smooth glide face 211, which operates as a press member against the smooth inner face of the hose mantle 201.
  • the glide shoe 210 has a series of hydrostatic chambers 212 placed one after the other, which chambers contribute to the formation of a hydrostatic loading pressure and to oil lubrication of the glide face 211.
  • Bach of the subsequent cylinder blocks 203 communicates with a pipe connector 214, to which pipes 213 of loading medium pass so that a separately adjustable pressure can be passed into each individual block in the series of cylinder blocks 203.
  • An example of the distribution of the nip pressure in an extended-nip zone NP is such a distribution in the machine direction in which the nip pressure (the pressure applied to the web W) at the front edge of the shoe 210 rises, owing to the hydrodynamically generated pressure, to about 40 bars, whereupon the pressure remains at this value as invariable, and in the trailing area of the shoe there is still an increase in the pressure, while the peak pressure is about 70 bars, from which value the pressure goes abruptly to zero at the trailing edge of the shoe 210.
  • said distribution of pressure can be varied so as to obtain an optimal pressing result.
  • the compression pressure at the hose roll 200 and the distribution of said pressure in the machine direction can be arranged such that the start of the dewatering, while the dry solids content of the web W is still relatively low, can be carried out so gently that the fibre structure of the web W is not deteriorated.
  • a regulation system related to the invention is sketched, by whose means the pressure profiles of the extended nip NP in the transverse direction and in the machine direction can be controlled.
  • the regulation system is illustrated by the block 250, from which a series of regulation signals c 1 is given which regulate the hydraulic pressures fed through the pipes 213.
  • a feedback signal is received from separate wirings 214, which is illustrated by the series of signals c 2 .
  • the system 250 communicates with a measurement arrangement 260, by whose means the different profiles of the paper web W produced, such as moisture or thickness profiles, are measured, and this provides a series of feedback signals c 3 for the regulation system 250, which produces the series of regulation signals c 1 .
  • the hose roll 200 is oil-tight, and the interior of the hose 201 can be arranged as slightly pressurized. From the glide faces 211 of the glide shoes 210, a slight leakage of oil takes place, which oil is collected from inside the hose mantle 201 and passed through the pipe 215 back to the oil circulation.
  • the hose roll 200 shown in Figs. 10 and 11 is preferably mounted on fixed bearing supports, in which case the extended nip NP must be opened by means of a movement of the backup roll. This is necessary, because a play of, e.g., about 40 mm for movement of the glide shoes 210 of the hose roll is not sufficient for opening the nip NP sufficiently, e.g., for replacement of the fabrics.
  • Fig. 12 shows a second embodiment of a hose roll 300.
  • a band 301 loop is used that is longer than the circular hose mantle 201.
  • Said band 301 is guided from inside and the extended nip NP is loaded by a hydrostatically and hydrodynamically loaded glide shoe 310, which is fitted inside the band 301 loop and which has a hydrostatically loadable series of pressure fluid chambers 312 in the area of the extended nip NP.
  • a beam 305 is fitted, which is provided with a series of hydraulic loading members 306 and 307, by whose means the glide shoe 310 can be loaded in a controlled way.
  • the band loop 301 is guided by a leading roll 311, in whose connection a spreader roll 312 is operative. Both ends of the band loop 301 are closed by means of end pieces so as to prevent oil leakages and splashes, of which end pieces one piece 312a is shown in Fig. 12.
  • the more detailed embodiment of the band roll shown in Fig. 12 comes out, e.g., from the applicant's FI Pat. Appl. No. 891380 (corresp. US Pat. Appl. 486,754).
  • the backup roll used in an extended nip NP as shown in Fig. 12 is an adjustable-crown roll 160, e.g. an adjustable-crown roll marketed by the applicant under the trade mark "Sym-Z Roll", which forms an extended nip NP by means of its sector C with the band roll 300.
  • a corresponding roll can be used together with the hose roll 200.
  • the roll 160 has a cylinder mantle 161, against whose smooth inner face 162 a series of glide shoes 165 operates, which is provided with hydraulic lubrication and loading chambers 166.
  • the series of shoes 165 is loaded by means of a series of hydraulic actuators 164.
  • the backup roll 160 is employed together with the fabric 60 as a member that receives water, the outer face of the mantle 160 is provided with a hollow face.
  • the principal purpose of the roll 160 is to heat the web 60, e.g., by means of induction heating devices 170, a smooth mantle face is employed on the roll.
  • a heating device in connection with the mantle 161 of the roll 160, a heating device is provided, e.g. an inductive heating device 170, by whose means the temperature profile of the roll mantle, and thereby the profile and the dewatering capacity of the extended nip, can be affected.
  • the roll 160 can also be used so that it has a smooth outer face and that by its means the web W is pressed directly, in which case there is no fabric 60 in between, and in this way the web W can be heated directly, thereby affecting the viscosity of the water present in the web and the elastic properties of the web W, thus promoting the dewatering and the transverse profile of the dry solids content.
EP96120948A 1990-11-23 1991-11-22 Verfahren und Vorrichtung zur Entwässerung einer Papierbahn durch Pressen Expired - Lifetime EP0770727B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FI905798 1990-11-23
FI905798A FI96789C (fi) 1990-11-23 1990-11-23 Menetelmä ja laite veden poistamiseksi paperiradasta puristamalla
EP91850291A EP0487483B1 (de) 1990-11-23 1991-11-22 Verfahren und Vorrichtung zur Entwässerung einer Papierbahn durch Pressen

Related Parent Applications (2)

Application Number Title Priority Date Filing Date
EP91850291.5 Division 1991-11-22
EP91850291A Division EP0487483B1 (de) 1990-11-23 1991-11-22 Verfahren und Vorrichtung zur Entwässerung einer Papierbahn durch Pressen

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EP0770727A1 true EP0770727A1 (de) 1997-05-02
EP0770727B1 EP0770727B1 (de) 2002-06-05

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EP91850291A Expired - Lifetime EP0487483B1 (de) 1990-11-23 1991-11-22 Verfahren und Vorrichtung zur Entwässerung einer Papierbahn durch Pressen
EP96120948A Expired - Lifetime EP0770727B1 (de) 1990-11-23 1991-11-22 Verfahren und Vorrichtung zur Entwässerung einer Papierbahn durch Pressen

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EP (2) EP0487483B1 (de)
AT (2) ATE218648T1 (de)
CA (1) CA2055927C (de)
DE (2) DE69129788T2 (de)
FI (1) FI96789C (de)

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EP0930392A2 (de) * 1998-01-20 1999-07-21 Voith Sulzer Papiertechnik Patent GmbH Pressenpartie
DE19934875A1 (de) * 1999-07-24 2001-01-25 Voith Paper Patent Gmbh Papiermaschine
US6413371B1 (en) 1998-06-10 2002-07-02 Metso Paper, Inc. Method for manufacture of paper and a paper machine
US6540873B2 (en) * 1999-09-06 2003-04-01 Metso Paper Karlstad Ab Board machine and method of manufacturing a multilayer cardboard web
WO2004022845A1 (en) * 2002-09-09 2004-03-18 Metso Paper, Inc A method of making paperboard, a machine for making paperboard and a press section for dewatering a wet fibrous web

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FI98844C (fi) * 1991-12-23 1997-08-25 Valmet Paper Machinery Inc Paperikoneen puristinosa, etenkin painopaperilaaduille
US5639351A (en) * 1991-12-23 1997-06-17 Valmet Corporation Press section of a paper machine, in particular for printing paper qualities
DE59301463D1 (de) * 1992-11-24 1996-02-29 Voith Gmbh J M Pressenpartie für eine Papiermaschine
FI93237C (fi) * 1993-06-11 1995-03-10 Valmet Tampella Inc Menetelmä ja laite paperi- tai kartonkikoneessa veden poistamiseksi rainasta
FI112391B (fi) * 1993-12-08 2003-11-28 Metso Paper Inc Paperikoneen puristinosa, jossa käytetään pitkänippipuristinta
US6368466B1 (en) * 1993-12-08 2002-04-09 Valmet Corporation Press section of a paper making machine employing an extended nip press
US5868904A (en) * 1993-12-08 1999-02-09 Valmet Corporation Press section employing an extended nip press with suction counter roll
FI95610C (fi) * 1994-10-06 1996-02-26 Valmet Paper Machinery Inc Tasauspuristimella varustettu paperikoneen puristinosa
US5876565A (en) * 1994-10-06 1999-03-02 Valmet Corporation Press section with an equalizing nip for compensating for elongation of a paper web
FI114227B (fi) 1995-04-24 2004-09-15 Metso Paper Inc Paperikone, jossa on puristinosa ja kuivatusosa
DE19535343A1 (de) * 1995-09-25 1997-03-27 Voith Sulzer Papiermasch Gmbh Verfahren und Maschine zum Herstellen von Faserstoff-Bahnen
DE19609988A1 (de) * 1996-03-14 1997-09-18 Voith Sulzer Papiermasch Gmbh Pressenpartie einer Papiermaschine
DE19702574A1 (de) 1997-01-24 1998-07-30 Voith Sulzer Papiermasch Gmbh Pressenanordnung
DE19705360A1 (de) * 1997-02-12 1998-08-13 Voith Sulzer Papiermasch Gmbh Preßvorrichtung zum Entwässern oder Glätten einer Faserstoffbahn
DE19708967A1 (de) * 1997-03-05 1998-09-10 Voith Sulzer Papiermasch Gmbh Pressenpartie
DE19802054A1 (de) 1998-01-21 1999-07-22 Voith Sulzer Papiertech Patent Pressenpartie
US6730192B1 (en) 1999-05-14 2004-05-04 Metso Paper, Inc. Method and machine for manufacturing printing paper or paperboard
ES2237428T3 (es) * 1999-05-14 2005-08-01 Metso Paper, Inc. Metodo y maquina para la fabricacion de papel o carton de impresion.
DE19938979A1 (de) * 1999-08-19 2001-02-22 Voith Paper Patent Gmbh Pressenpartie
EP1342839B1 (de) 2002-03-01 2006-11-22 Voith Patent GmbH Verfahren und Vorrichtung zur Messung der Härte oder Verdichtung einer Bespannung
DE10233924A1 (de) * 2002-07-25 2004-02-12 Voith Paper Patent Gmbh Verfahren zum Betreiben einer Papiermaschine
FI116400B (fi) * 2002-11-19 2005-11-15 Metso Paper Inc Paperi- tai kartonkikoneen puristinosa
DE10332906A1 (de) * 2003-07-19 2005-02-17 Voith Paper Patent Gmbh Entwässerungspresse
DE10343215A1 (de) * 2003-09-18 2005-04-14 Voith Paper Patent Gmbh Schuhwalze
JP2006257602A (ja) * 2005-03-18 2006-09-28 Ichikawa Co Ltd 抄紙機および抄紙搬送ベルトの再生方法
DE102007035548A1 (de) * 2007-07-28 2009-01-29 Voith Patent Gmbh Pressanordnung
SE539535C2 (sv) * 2013-11-07 2017-10-10 Stora Enso Oyj Förfarande för avvattning av en suspension innefattande mikrofibrillerad cellulosa

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DE3815278A1 (de) * 1988-05-05 1989-11-16 Voith Gmbh J M Pressenpartie einer maschine zur herstellung einer faserstoffbahn, insbesondere papierbahn
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US4483745A (en) 1982-09-29 1984-11-20 Beloit Corporation Method and apparatus of sheet transfer using a nonporous smooth surfaced belt
US4584059A (en) 1983-04-02 1986-04-22 J. M. Voith Gmbh Belt press unit, preferably as wet press of a paper machine
WO1985000841A1 (en) 1983-08-04 1985-02-28 J. M. Voith Gmbh Paper machine
US4561939A (en) 1984-03-26 1985-12-31 Beloit Corporation Extended nip press arrangement
DE3742848A1 (de) 1987-12-17 1989-06-29 Escher Wyss Gmbh Pressenpartie einer papiermaschine
US4915790A (en) * 1987-12-17 1990-04-10 Hans Dahl Press section of a papermaking machine with adjustable felt guide roll

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0930392A2 (de) * 1998-01-20 1999-07-21 Voith Sulzer Papiertechnik Patent GmbH Pressenpartie
EP0930392A3 (de) * 1998-01-20 2001-01-10 Voith Paper Patent GmbH Pressenpartie
US6589390B1 (en) 1998-01-20 2003-07-08 Voith Sulser Papiertechnik Patent Gmbh Press section and process for guiding a fiber material web through the press section
US6413371B1 (en) 1998-06-10 2002-07-02 Metso Paper, Inc. Method for manufacture of paper and a paper machine
DE19934875A1 (de) * 1999-07-24 2001-01-25 Voith Paper Patent Gmbh Papiermaschine
EP1072721A2 (de) * 1999-07-24 2001-01-31 Voith Paper Patent GmbH Papiermaschine
EP1072721A3 (de) * 1999-07-24 2001-08-22 Voith Paper Patent GmbH Papiermaschine
US6638395B1 (en) 1999-07-24 2003-10-28 Voith Sulzer Papiertechnik Patent Gmbh Paper machine and process
US6540873B2 (en) * 1999-09-06 2003-04-01 Metso Paper Karlstad Ab Board machine and method of manufacturing a multilayer cardboard web
WO2004022845A1 (en) * 2002-09-09 2004-03-18 Metso Paper, Inc A method of making paperboard, a machine for making paperboard and a press section for dewatering a wet fibrous web

Also Published As

Publication number Publication date
CA2055927C (en) 1999-02-02
FI905798A0 (fi) 1990-11-23
DE69129788T2 (de) 1998-11-19
DE69133030T2 (de) 2002-11-21
FI96789B (fi) 1996-05-15
FI905798A (fi) 1992-05-24
DE69129788D1 (de) 1998-08-20
DE69133030D1 (de) 2002-07-11
CA2055927A1 (en) 1992-05-24
FI96789C (fi) 1996-08-26
EP0487483A1 (de) 1992-05-27
EP0770727B1 (de) 2002-06-05
ATE168423T1 (de) 1998-08-15
EP0487483B1 (de) 1998-07-15
ATE218648T1 (de) 2002-06-15

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