ES2237428T3 - METHOD AND MACHINE FOR THE MANUFACTURE OF PAPER OR PRINT CARTON. - Google Patents

Abstract

For manufacturing printing paper or paperboard with a grammage of 30-200 g/m<2> in a paper or paperboard machine, comprising a wet section, a press section and a drying section, and in which a formed web (W) is pressed in a roll press with a double-felted roll-press nip and, thereafter, in a shoe press with an extended single or double-felted shoe-press nip, it is suggested, in accordance with the invention that the web is pressed in a deflection-compensating roll press, having said double-felted roll-press nip and open press rolls; that the machine is operated at a web speed of at least 1,200 m/min.; that the web in the roll-press nip is subjected to a linear load ranging from 100 to 300 kN-m and a specific pressure ranging from 5 to 15 MPa; and that the web in the shoe-press nip is subjected to a linear load ranging from 500 to 1,500 kN/m and a specific high pressure ranging from 4 to 13 MPa, to obtain a dewatered web with a dry-solids content of at least 35 per cent after the roll-press nip and at least 45 per cent after the shoe-press nip.

Description

Method and machine for papermaking or printing cardboard

The present invention relates to a method for the manufacture of paper or cardboard with a grammage of 30-200 g / m2 in a papermaking machine or cardboard, comprising a wet section, a press section and a drying section

The invention also relates to a machine for the manufacture of paper or cardboard at high speed, whose paper or cardboard has a weight of 30-200 g / m2, the machine comprising a wet section, a press section and a drying section, whose press section includes a press of rollers an interstice of the double felt roller press, and a shoe press, which has a shoe press gap single felt or double felt.

US-4,561,939 A describes a papermaking machine with a section of press, consisting of a double felt roller press and a double felt shoe press. The roller press is of a conventional type that has grooved rollers with surfaces rigid envelopes. Such a configuration excludes the high belt speeds. After the press gap in the roller press, a suction shoe is arranged in the bottom felt loop of the press, whose shoe aspiration is intended to act so that the tape accompanies the bottom felt of the press. However, at high speeds, a suction shoe cannot ensure such tape behavior. The suction shoe is an element important in the press section according to this report descriptive of the patent, which does not suggest or describe, therefore, other suction devices to ensure behavior correct belt at high speeds. This descriptive report also use a suction shoe after the second double felt press gap, which contributes, so therefore, to an additional limitation of this known machine for the papermaking with respect to the speed of the tape. Bliss Patent specification is limited to a shoe press double felt for the second interstitium of the press and, therefore therefore, it does not describe a transfer belt to replace one of the press felts to allow a safe run of the tape and therefore higher speeds. Nor does he recognize the possibility of operating with a transfer belt to very high speeds and to obtain a good solid content also dried for mechanical pulp, which is used for manufacture of newsprint, LWC base paper and SC paper. The known papermaking machine also lacks boxes of blowing that generate partial voids to ensure firm fixation from the belt to the felt of the press to allow high speeds, which lead to strong air flow, which can easily separate the tape from the felt of the press.

US 5 639 351 A describes a method for the manufacture of printing paper with a weight of 40 to 80 g / m2 in a papermaking machine comprising a section wet, a press section and a drying section. In this method, a tape formed in the wet section is pressed into a roller press with a gap of roller press double felt, the roller press comprising a roller suction and a compensation press roller that forms the interstice of the roller press in the middle, comprising the surface clearing press roller swivel articulated envelope, a stationary beam and a shoe member that is disposed between the beam and the surface envelope, in which the suction roller and the roller deflection compensation are arranged in such a way that the Shoe member does not act against the suction roller. The tape, after being pressed in the roller press, is transferred to a shoe press with a press gap of individual felt shoes extended and pressed into said shoe press. The machine is driven at a speed of tape of at least 1,200 m / min. In the interstice of the press of rollers, the tape is subjected to a linear load that extends from 10 to 120 kN / m, preferably from 30 to 80 kN / m, and at a specific pressure that varies from 0.2 to 2 MPa, and in the gap of the shoe press, the tape is subjected to a linear load that varies from 10 to about 30 times the limit load in the interstice of the roller press and at a specific pressure that varies from 5 to about 50 times the specific pressure in the gap of the roller press, to obtain a dehydrated tape with a solids content dry about 25 to 33 percent after the interstitium of the roller press and about 48 to 54 percent after the gap of the shoe press.

US 5 639 351 A also describes a paper making machine to make printing paper at high speed, whose printing paper has a weight of 40 to 80 g / m2, the machine comprising a wet section, a section Press and a drying section. The press section includes a roller press having a roller press gap of double felt, and a shoe press that has an interstitium of Extended individual felt shoe press. The press of rollers comprises a suction roller and a press roller of deflection compensation that forms the interstitium of the roller press in the middle, comprising the roller press of deflection compensation an articulated enveloping surface of rotating form, a stationary beam and a shoe member that is disposed between the beam and the enveloping surface, in which the suction roller and the compensation press roller of the deflection are arranged so that the shoe member does not acts against the suction roller. The machine is ready to be driven at a belt speed of at least 1,200 m / min, with a linear load in the interstitium of the press of rollers extending from 10 to 120 kN / m, preferably from 30 to 80 kN / m, and at a specific pressure that varies from 0.2 to 2 MPa, and that oscillates in the interstitium of the press of shoes from 10 to about 30 times the linear load in the gap of the roller press and at a specific pressure in the gap of the roller press ranging from 0.2 to 2 MPa and that varies in the interstice of the shoe press from 5 up to 50 times the specific pressure in the interstitium of the press of rollers, to obtain a dehydrated tape with a content of dry solids of approximately 25 to 33 percent after gap of the roller press and approximately between 48 and 54 percent after the gap of the shoe press.

The object of the present invention is provide an improved method and an improved machine of paper or cardboard manufacturing that allows the manufacture of paper or printing cardboard at very high speeds and which also allows high efficiency and a large increase in productivity.

According to the invention, the object is achieved by the method of claim 1 and by the machine of the claim 11.

The invention is further described below. With reference to the drawings.

Figure 1 schematically shows arts of a machine, according to a first embodiment of the invention, for the manufacture of a tape of a fiber material of cellulose.

Figure 1a shows parts of a section of press, modified in relation to a section in the machine according to figure 1.

Figure 2 schematically shows parts of a machine, according to a second embodiment of the invention.

Figure 3 schematically shows parts of a machine, according to a third embodiment of the invention.

Figure 3a shows parts of a machine, whose press section is modified in relation to a section in the machine according to figure 3.

Figure 4 schematically shows parts of a machine, according to a fourth embodiment of the invention.

Figure 5 shows in detail the special press of rollers that are part of the embodiments shown according to figures 1 to 4.

Figures 1 to 4 show schematically machine parts for paper or cardboard manufacturing printing paper or cardboard on a continuous tape W. Each of the machines comprises a wet section 1, a press section 2 and a drying section 3.

The wet section 1, of which is shown only its downstream part comprises a forming wire 4, which extends in a loop around guide rollers 5. In the embodiment according to figure 1, a roller of suction 46 is arranged in the loop of the forming wire 4 immediately upstream of an admission point. A roller of Suction of this type is not always used on wire parts of more recent design, as illustrated in figures 2 to 4.

The drying section 3 comprises a plurality of drying cylinders 7 and rollers 8, which can be rollers grooves or blind drill rollers, as shown or, of a alternative way, smooth rollers or suction rollers conventional with or without an internal suction box with sealing devices (in the latter case with internal vacuum) or with the so-called "Vac" rollers, which have grooves, drills in the grooves and a partial vacuum in the roller.

Press section 2 comprises a press of 9 and double felt rollers, downstream of the roller press 9, a shoe press 10, which can be a shoe press of individual felt according to figures 1 and 3 or a press of double felt shoes according to figures 2 and 4. The press roller 9 comprises an open upper press roller 11 and an open bottom press roller 12, whose press rollers 11, 12 cooperate with each other to create a press gap of rollers between them. In addition, the roller press 9 comprises a endless press felt 13 endless, upper felt, which extends in a loop through the gap of roller press around a plurality of guide rollers 14, and a felt of bottom press 15 endless, bottom felt, which extends into a loop through the interstice of the roller press around a plurality of guide rollers 16.

The upper felt 13 of the roller press acts as an admission felt and has, in its loop, a roller of intake intake 18, arranged in close proximity to the forming wire 4 to transfer the tape W from the wire of formation 4 towards the upper felt 13.

In the embodiments according to the Figures 1 and 2, the bottom felt 15 acts as the felt of transfer, which carries the W tape from the interstitium of the roller press towards shoe press 10 while in the embodiments according to figures 3 and 4, the upper felt 13 acts as the transfer felt. At press felt loop 13 or 15, respectively, which acts as transfer felt, blow boxes are arranged that generate partial vacuum or suction boxes 17 downstream of the press gap within the area where the felt of the Press 13 or 15, respectively, wears the tape W. In the forms of embodiment according to figures 1 and 2, a roller of suction 6 is additionally arranged in the felt loop lower 15 at a point downstream from the interstitium of the press of rollers, where the felt of the press 13, 15 diverges one of the another, ensuring the suction roller 6 that the tape W accompanies to the bottom felt 15.

A steam box 19 is arranged in the proximity of the outer side of the upper felt 13 downstream of the intake suction roller 18 for conditioning favorable of the W tape with steam before pressing it in the first press gap.

The shoe press 10 comprises a roller of shoe press 20 and an opposite roller 21, whose rollers 20, 21 cooperate with each other to create an extended press gap of shoes. The shoe press 10 further comprises a first Endless press lining 22 in the form of a press felt, that extends in a loop through the extended interstitium of the shoe press around shoe press roller 20, around a plurality of guide rollers 23 and around a intake suction roller 24, which is arranged in the close proximity to the bottom felt 15 that carries the tape or to the upper felt 13, respectively, of the roller press 9 to remove and transfer the tape W from the bottom felt 15 carrying the tape or from the upper felt 13, respectively, from the roller press 9 to the press felt 22 of the shoe press 10, allowing the press felt 22 of the Shoe press 10 also acts as an admission felt. The blow boxes that generate partial vacuum or suction boxes 25 are arranged in the press felt loop 22 of the press of shoes 10, downstream of the intake suction roller 24, to retain the tape W on the outer side of the press felt 22 of the shoe press 10 in front of the extended interstitium of the shoe press. In the embodiment according to the Figure 4, the loop of the press felt 22 houses a roller of aspiration 30 downstream of the extended interstitium of the press and of a next blow box that generates a partial vacuum or box suction 31.

The shoe press 10 further comprises a second endless press fitting 26, which extends in a loop through the extended gap of the shoe press around of the press roller 21 and about a plurality of rollers Guide 27. In the embodiments according to the figures 2 and 4, the second press fitting 26 is a press felt 26a, while in the embodiments according to the Figures 1 and 3, is a waterproof transfer belt or substantially impermeable 26b having a smooth surface of contact with the tape. The first press garrison, that is, the press felt 22, in whose loop the roller is located shoe press 20, is arranged in an upper position (such as the shoe press roller 20) in the embodiments of according to figures 1 and 2, while arranged in a lower position (such as shoe press roller 20) in the embodiments according to figures 3 and 4. In the form according to figure 2, a suction roller 28 and a next blow box that generates partial vacuum or box of suction 29 are located downstream of the interstitium extended from the press into the loop of the press felt 26a, which houses the opposite roller 21.

In the embodiments shown, the opposite roller 21 of the shoe press 10 is shown as a grooved roller or blind roller. In one way Alternatively, the opposite roller is a smooth roller.

In the embodiments according to the Figures 1 and 2, the tape W is transferred from the bottom felt 15 of the roller press 9 to the upper felt 22 of the shoe press 10 while in the embodiments of according to figures 3 and 4, the tape W is transferred from the upper felt 13 of the roller press 9 to the felt bottom 22 of the roller press 10. The bottom fitting 26 of the shoe press 10, in the embodiments according to with figures 1 and 2, and the lower lining 22 of the press shoes 10, in the embodiment according to figure 4, are willing to wear the tape W after the gap extended from the shoe press to the drying section 3; while, in the embodiment according to figure 3, the upper lining 26 of the shoe press 10 in the form of the transfer belt 26b is arranged to carry the tape W after the extended gap of the shoe press.

The drying section 3 comprises a lining 32 endless permeable drying in the form of a mesh dryer or felt dryer, which extends in a loop around a plurality of guide rollers 33, the drying cylinders 7 and the rollers 8. In the embodiments according to the figures 1, 2 and 4, the mesh dryer or the felt dryer 32 extends also around an intake suction roller 34, which it is arranged in close proximity to the lower lining 22 alternatively 26a or 26b of the shoe press 10, of so that the pressed tape W is transferred from the lining bottom 22 in an alternative way to the mesh dryer or felt dryer 32. The blowing boxes that generate partial vacuum or suction boxes 35 are arranged in suitable places in the mesh dryer loop or felt dryer 32. The shape of embodiment according to figure 3 employs a fitting of admission 36 endlessly separated, which can be a wire or a felt and that extends in a loop around a plurality of rollers guide 37 and an intake suction roller 38, arranged in close proximity of the second press fitting 26 of the shoe press 10, that is, the transfer belt 26b, to transfer the pressed tape W from the transfer belt 26b to the intake fitting 36. A blow box that generates partial vacuum or suction box 39 is disposed waters below the intake suction roller 38 in the loop of the intake wire or intake felt 36. In the form of embodiment according to figure 3, the first water roller 8 above in the drying section is arranged in the vicinity close to the intake wire or intake felt 36, so that the pressed tape W is transferred from the intake wire or intake felt 36 to the mesh dryer or felt dryer 32

A steam box 40 is arranged in a space free, where the lower side of the tape W is exposed, located between the bottom felt 15 of the roller press 9 and the lining bottom 22 or 26, respectively, of the shoe press 10, in the close proximity to the upper felt 13 of the press rollers 9 according to figure 3, for example, or according to the upper lining 26 or 22, respectively, of the press of shoes according to figure 1.

The designation number 41 denotes a team suitable for conditioning press felts 13, 15, 22, 26a.

As evidently deduced from the drawings, the press section has a closed tape that extends from the wet section to the drying section and provides good operating capacity for all grades of printing paper as well as allows operating speeds very high The press section has two press interstitium optimized for good working capacity and good dry solids content. The suction roller and the boxes of blown after the interstitium of the rollers provides a Good working capacity. The second interstitium of the press is a shoe press gap, where you can use a very high interstitium load and you can get a Very high dry solids content. Using a steam box in front of the first interstitium of the press and especially after from the second press gap, you can get a improved dry solids content and the profile can be controlled of dry solids content.

In all points of admission are present suction rollers to ensure that the belt is transferred from one garnish to the other, as well as blow boxes that generate partial vacuum or suction boxes to ensure that the tape is retained attached to the garnish. These measures they also contribute to a good working capacity and allow operation at very high speeds without cause breakage of the tape. The partial vacuum in the roller aspiration 6 is in the range of approximately 10-30 kPa, in the suction roller 24 is in the range of approximately 15 and 40 kPa and in the suction roller 28 is between approximately 10 and 30 kPa, if this is used. Partial vacuum in the suction roller 34 is the interval of approximately 15 and 40 kPa. The blowing boxes 17, 25, 29 that generate a partial vacuum provide a partial vacuum of approximately 300 to 1000 Pa.

A transfer belt of the type shown in Figures 3 and 4 for transferring the tape from the press Roller to shoe press is particularly suitable for the manufacture of cardboard, since there are open interstices, wedge shaped after press gap of rollers and in front of the gap of the shoe press.

Figure 1a shows parts of a section of the press similar to that of the machine according to figure 1, but with a modified configuration of the shoe press 10 with with respect to the extension of the lower press lining 26, that is, the transfer belt 26b, in relation to the felt upper 22 in front of the extended gap of the press of shoes. The guide roller 27a located closest to the shoe press gap is high and ready next to the upper felt 22 so that, in the direction away from the raised guide roller 27a, transfer belt 26b is extends in contact with the upper felt 22, enclosing the tape W between them to form a sandwich construction. A roller of additional guide 23a is arranged in the felt loop upper 22 in a position of said raised guide roller 27a to create a gap that does not compress the tape. The press of shoes on the machine according to figure 2 can be modified in the same way as shown in figure 1a. The use of a sandwich construction of this type, which follows after the box of steam 30, means that the distance between the tape W and the box Steam 40 becomes very accurate. In addition, the number of boxes of blowing that generates partial vacuum or suction boxes 25 se can reduce to one in the embodiment shown in the figure 1a.

Figure 3a shows part of a machine similar to that shown in accordance with Figure 3, but with a modified configuration of the roller press 9 and the shoe press 10 with respect to the extension of the lower press lining 15, 22 and the upper press fittings 13, 26 relative to each other behind and in front of the press gap. In the loop of the upper felt 13 of the roller press 9, a suction roller 47 is disposed downstream of the gap of the roller press to guide the upper felt 13 in contact with the lower felt 15 in such a way that the upper felts and lower 13, 15 and the tape W enclosed between them form a sandwich construction after the interstice of the roller press. In such an embodiment, with a suction roller 47 in the loop of the upper felt 13 carrying the tape, it is possible to reduce the number of blow boxes generating partial vacuum or suction boxes 17, for example, to only one according to the embodiment shown. In the loop of the transfer belt 26b of the shoe press 10, the upstream guide roller 27a located closest to the interstice of the shoe press is lowered and arranged near the bottom felt 22, so that in the direction Outside the lower guide roller 27a, the transfer belt 26b extends in contact with the lower felt 22, enclosing the tape W between them to form a sandwich construction. An additional guide roller 23a may be disposed in the lower felt loop 22 to support the sandwich construction, if so desired. Accordingly, in such an embodiment of the shoe press 10, where the belt W is enclosed in a sandwich construction, no blowing boxes that generate partial vacuum or suction boxes are required in this embodiment. One or more such suction boxes 25 are arranged along all or part of the area where the belt extends with its upper side exposed, that is, in a closed section in front of said construction in the shoe press, the number of boxes 25 being adapted to the length of the closed section. The machine according to figure 4 can be modified in the same way as the machine according to figure 3 to obtain a sandwich construction after the gap of the roller press as well as in front of the gap of the shoe press in accordance with the figure
3rd.

A section of tape of the type shown in the Figure 3a to transport the belt from the interstitium of the roller press until the gap of the shoe press is particularly suitable for making printing paper at high speeds, since the open gaps have been removed in wedge shape after the interstice of the roller press and in front of the gap of the shoe press.

In the embodiment shown on the machine according to the invention, the press rollers of the press of rollers are of the type of deflection compensation, as illustrated in detail in figure 5. Each press roller has a swivel wrap surface 42 and a static inner beam configured in the form of I 43, which extends axially between the extreme walls and supporting an elongated shoe member 44 that comprises a plurality of hydrostatic sliding shoes or hydrodynamics, arranged in a row and located hydraulically between the I-shaped beam and the surface envelope 42 by means of power cylinders 45, being maintained a thin film of oil between each shoe of sliding and the inside of the envelope. Thanks to one construction of this type, the vibrations in the Press rollers in a very effective way. Therefore both shoe members 44 act against the inner sides of the enveloping surfaces within the interstice of the press of rollers and can be controlled section by section in relation to yes to compensate for deflections on the surfaces of the Envelope of press rollers. The press rollers are provided with blind holes or grooved. In one way preferred, the enveloping surface of each press roller has an outer layer of steel, showing grooves with a width of approximately 0.5 mm and a depth of approximately 5 mm, for example, the distance cc being between two parallel slots adjacent approximately 2.25 mm, for example. Therefore the slotted press roller has an added volume of very grooves large, namely 1.1 dm 3 / m2 of enveloping surface with the specified values of the slots. It has been found that a Slot volume so large is favorable to avoid currents of water and crushing. The narrow grooves (0.5 mm) prevents the groove marks on the tape. Since the grooved layer It is made of steel, the volume of the grooves is maintained constant during pressing even with very high linear loads in the interstice of the roller press. The properties described of the press rollers therefore contribute to very high belt speeds can be achieved and at can obtain high levels of dry solids contents already after the first press gap without crushing the headband. N general, the aggregate volume of slots or gaps is in the range of 0.7 and 1.9 dm 3 / m2 surface envelope

Therefore, the press rollers of deflection compensation effectively eliminates vibrations created with high linear loads, with pressures higher specific high and at high belt speeds.

The linear load in the interstitium of the press of Rollers are in the range of 100 - 300 kN / m, preferably between 120 and 250 kN / m, and in the gap of the shoe press between 500 and 1,500 kN / m, in a preferred manner between 700 and 1,200 kN / m The specific pressure in the interstitium of the press of Rollers are in the range of 5 and 15 MPa, in a preferred way between 8 and 11 MPa, and in the gap of the shoe press between 4 and 13 MPa, preferably 4 to 8 MPa.

The dry solids content of the tape after of the wet section is, in general, in the range of 15-22 percent, depending on the type of printing paper, the Dry solids content for thin paper normally between 18 and 22, for newsprint and LWC base paper, 16 to 18 percent, and for SC paper, 15 to 17 percent.

In general, the speed of the tape is currently, in general, in the range of 1,200 to 1,700 m / min, depending on the type of printing paper, among other factors, being the speed for the fine paper in the modern machines of papermaking and in the press sections typically of a way approximately 1,200 to 1,500 m / min., for newsprint approximately 1,300 to 1,700 m / min., for LWC base paper approximately 1,400 to 1,600 m / min. and for approximately SC paper 1,400 at 1,600 m / min.

To obtain good operating capacity a very high speeds, that is, greater than 1,700 m / min., the press of shoes 10 is provided in a preferred manner with a strap transfer, which is more favorable in the lower position, is say, according to figure 1.

The higher the dry solids content After the roller press, the better the ability to operation between the roller press and the press shoes.

When the shoe press uses a belt transfer and a press felt, the water will be expelled by pressed out of the tape in one direction, that is, towards the press felt, which means that the tape becomes asymmetric, having dissimilar sides (smooth and uneven, respectively). Therefore, it is considered appropriate that the more water can be removed from the tape in the gap Double felt roller press, so much less water should be eliminated in the interstice of the shoe press, which gives place to an improved symmetry of the density in the z direction.

He then realizes the drawings and the results of a number of experiments in the manufacture of different grades of printing paper, whose properties are the following.

Thin paper: chemical pulp, filler content approximately 12 to 18 percent, the filling being usually calcium carbonate, weight 40 to 200 g / m2.

Press paper: mechanical pulp, without filling, weight approximately 40 to 48 g / m2.

SC paper: 70 to 80 percent mechanical pulp and chemical paste 30 to 20 percent, kaolin filling approximately 30 percent, weight approximately 42 to 56 g / m2.

LWC base paper: 55 to 60 mechanical pulp per percent, chemical paste 45 to 40 percent, filling approximately 5 at 15 percent, weight 33 to 45 g / m2.

Experiment one

Section of the press: According to figure 1 Kind of printing paper: Base paper LWC Weight: 40 g / m2 Belt Speed: 1,500 m / min Design of the first press: Grooved rollers Design of the second press:  \ begin {minipage} [t] {93mm} Length of the 200 mm shoe, shoe press roller with surface slotted envelope, transfer belt as a fitting bottom \ end {minipage}

Linear load in the first press: 200 kN / m Linear load in the second press: 1,100 kN / m Specific pressure in 1st press: 9.0 MPa Specific pressure in 2nd press: 7.3 MPa

Results

Dry solids content after the 1st press: 39 percent Content of Dry solids after the 2nd press: 49 for hundred

Experiment 2

Section of the press: According to figure 1 Kind of printing paper: Paper SC Weight: 56 g / m2 Belt Speed: 1,500 m / min Design of the first press: Grooved rollers Design of the second press:  \ begin {minipage} [t] {93mm} Length of the 200 mm shoe, shoe press roller with surface slotted envelope, transfer belt as a fitting bottom \ end {minipage}

Linear load in the first press: 200 kN / m Linear load in the second press: 1,100 kN / m Specific pressure in 1st press: 9.0 MPa Specific pressure in 2nd press: 7.3 MPa

Results

Dry solids content after the 1st press: 42 percent Content of Dry solids after the 2nd press: 57 for hundred

Experiment 3

Press section : According to figure 1 Kind of paper of impression: Paper fine Weight: 80 g / m2 Belt Speed: 1,500 m / min Design of the first press: Grooved rollers Design of the second press:  \ begin {minipage} [t] {93mm} Length of the 200 mm shoe, shoe press roller with surface slotted envelope, transfer belt as a fitting bottom \ end {minipage}

Linear load in the first press: 200 kN / m Linear load in the second press: 1,100 kN / m Specific pressure in 1st press: 9.0 MPa Specific pressure in 2nd press: 7.3 MPa

Results

Dry solids content after the 1st press: 38 percent Content of Dry solids after the 2nd press: 48 for hundred

Experiment 4

Section of the press:  \ begin {minipage} [t] {93mm} According to the Figure 2, but the tape extends to the first interstitium of according to figure 1 \ end {minipage} Kind of printing paper: Paper fine Weight: 101 g / m2 Belt Speed: 1,200 m / min Design of the first press: Grooved rollers Design of the second press:  \ begin {minipage} [t] {93mm} Length of the 250 mm shoe, shoe press roller with surface slotted envelope, transfer belt as a fitting bottom \ end {minipage}

Linear load in the first press: 200 kN / m Linear load in the second press: 1,000 kN / m Specific pressure in 1st press: 9.0 MPa Specific pressure in 2nd press: 6.2 MPa

Results

Dry solids content after the 1st press: 38.9 percent Content of dry solids after the 2nd press: 46.1 per hundred

Experiment 5

Section of the press: According to figure 1 Kind of printing paper: Paper SC Weight: 52 g / m2 Belt Speed: 1,400 m / min Design of the first press: Grooved rollers Design of the second press:  \ begin {minipage} [t] {93mm} Length of the 220 mm shoe, shoe press roller with surface slotted envelope, transfer belt as a fitting bottom \ end {minipage}

Linear load in the first press: 250 kN / m Linear load in the second press: 1,200 kN / m Specific pressure in 1st press: 10.0 MPa Specific pressure in 2nd press: 7.5 MPa

Results

Dry solids content after the 1st press: 42.9 percent Content of dry solids after the 2nd press: 49.6 per hundred

Experiment 6

Section of the press: According to figure 1 Kind of printing paper: Paper SC Weight: 52.3 g / m2 Belt Speed: 1,200 m / min Design of the first press: Grooved rollers Design of the second press:  \ begin {minipage} [t] {93mm} Length of the 200 mm shoe, shoe press roller with surface slotted envelope, transfer belt as a fitting bottom \ end {minipage}

Linear load in the first press: 250 kN / m Linear load in the second press: 1,200 kN / m Specific pressure in 1st press: 10.0 MPa Specific pressure in 2nd press: 7.5 MPa

Results

Dry solids content after the 1st press: 46.1 percent Content of dry solids after the 2nd press: 51.4 per hundred

Experiment 7

Section of the press:  \ begin {minipage} [t] {93mm} According to the Figure 2, but the tape extends to the first interstitium of according to figure 1 \ end {minipage} Kind of printing paper: Paper fine Weight: 80 g / m2 Belt Speed: 1,200 m / min Design of the first press: Grooved rollers Design of the second press:  \ begin {minipage} [t] {93mm} Length of the 250 mm shoe, shoe press roller with surface slotted envelope, transfer belt as a fitting bottom \ end {minipage}

Linear load in the first press: 250 kN / m Linear load in the second press: 700 kN / m Specific pressure in 1st press: 10.0 MPa Specific pressure in 2nd press: 4.2 MPa

Results

Dry solids content after the 1st press: 42 percent Content of Dry solids after the 2nd press: 45 for hundred

Experiment 8

Section of the press: According to figure 1 Kind of printing paper: Paper press Weight: 48 g / m2 Belt Speed: 1,500 m / min Design of the first press: Grooved rollers Design of the second press:  \ begin {minipage} [t] {93mm} Length of the 220 mm shoe, shoe press roller with surface slotted envelope, transfer belt as a fitting bottom \ end {minipage}

Linear load in the first press: 250 kN / m Linear load in the second press: 1,100 kN / m Specific pressure in 1st press: 10.0 MPa Specific pressure in 2nd press: 6.2 MPa

Results

Dry solids content after the 1st press: 38 percent Content of Dry solids after the 2nd press: 48 for hundred

Experiment 9

Section of the press: According to figure 1 Kind of printing paper: Paper SC Weight: 52 g / m2 Belt Speed: 1,600 m / min Design of the first press: Grooved rollers Design of the second press:  \ begin {minipage} [t] {93mm} Length of the 220 mm shoe, shoe press roller with surface slotted envelope, transfer belt as a fitting bottom \ end {minipage}

Linear load in the first press: 200 kN / m Linear load in the second press: 700 kN / m Specific pressure in 1st press: 9.0 MPa Specific pressure in 2nd press: 6.2 MPa

Results

Dry solids content after the 1st press: 41 percent Content of Dry solids after the 2nd press: 55 for hundred

The experiments presented above show that you can get good levels of content from dry solids at high belt speeds. The results are surprising, since it had been previously considered that a short roller gap, 40 to 60 mm, which results in a short residence time, 1.2 to 2.5 ms, does not provide a Good dry solids content at high machine speeds. In all experiments, with different grades of paper or grammage, the tape was pressed in the first press interstitium of Rollers without being crushed. This is very surprising.

A press section with a first press in shape of a double felt roller press and a second press in the form of a shoe press constitute a cheaper configuration than a press section with two shoe presses.

The first press roller provides very good levels of dry solids contents with linear loads in the gap of the roller press from 120 to 250 kN / m, which in some cases is much better than the one provided by a press of shoes with a linear load of 1,000 kN / m. The reason for this is that high speed linear roller press creates pressures specific upper much higher than a shoe press with an extended gap with a high load. This results in a good water removal and a good dry solids content, especially in the interstice of the double roller press felt.

Press rollers open compensation deflection in the upper and lower positions prevent a very effective way the vibrations that constitute a problem with ordinary solid press rollers when linear loading And the speed of the tape are high. The two press rollers open deflection compensation described have their shoe members acting against each other and therefore the stresses on the wrapping surfaces of the rollers of press will be low with high linear loads in the interstitium of the roller press Press rollers open compensation deflection does not require cant formation and therefore therefore, the CD profile can be controlled in the interstitium of the roller press to make it very straight. In addition, the profile of the humidity of the felt of the press will be good and the Felt service life.

Claims (23)

1. A method for making paper or printing cardboard with a weight of 30 to 200 g / m2 in one paper or cardboard manufacturing machine comprising a section wet (1), a press section (2) and a drying section (3), in whose method

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a tape (W) formed in the wet section (1) is pressed into a press of rollers (9) with a felt roller press gap double, said roller press (9) comprising two rollers of open deflection compensation press (11, 12) that form the gap of the roller press in the middle, comprising each one of said two press rollers (11, 12) a surface envelope (42) with blind or grooved holes, articulated rotating, a stationary beam (43) and a shoe member (4) disposed between said beam (43) and said envelope surface (42), said shoe member (44) comprising a plurality of shoes of sliding loaded hydraulically, in which said two shoe rollers (44) act against each other,

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the tape (W), after being pressed in said press of rollers (9), is transferred to a shoe press (10) with a Extended gap of individual felt shoe press or double felt and is pressed in said shoe press (10),

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the machine is driven at a belt speed of at least 1,200 m / min.,

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the belt (W) in said interstice of the roller press is subjected at a linear load that varies from 100 to 300 kN / m, in a way preferred from 120 to 250 kN / m, and at a specific pressure that ranges from 5 to 15 MPa, in a preferred manner from 8 to 11 MPa,

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the belt (W) in said gap of the shoe press is subjected to a linear load that varies from 500 to 1,500 kN / m, in a way preferred from 700 to 1,200 kN / m, and at a specific pressure that ranges from 4 to 13 MPa, in a preferred way from 4 to 8 MPa,

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for obtain a dehydrated tape (W) with a dry solids content at least 35 percent, in a preferred manner at least 38 per hundred, after the interstice of the roller press and at least 45 percent after the press gap of shoes.

2. A method according to claim 1, characterized in that the belt (W), after the gap of the roller press, is transferred to the shoe press (10) by one of the press felts (15 or 13) of the interstitium of the double felt roller press and is brought to adhere to one of said press felts (15 or 13) that acts as a transfer felt with the help of a suction roller (6, 47) and / or one or several blow boxes that generate a partial volume or suction boxes (17). 3. A method according to claim 1, characterized in that the gap of the shoe press is double felt and because the tape (W), after the gap of the shoe press, is transferred to the drying section (3) by one of the felts of the press (26 or 22) of the interstitium of the double felt shoe press and is brought to adhere to one of said press felts (26 or 22) that acts as a transfer felt with the help of a suction roller (28, 30) and / or one or several blow boxes that generate a partial volume or suction boxes (29, 31). 4. A method according to claim 1, characterized in that the gap of the shoe press is of individual felt and that the tape (W), after the gap of the shoe press, is transferred to the drying section (3) by an additional lining of the press that passes through the gap of the shoe press and which is provided in the form of an impermeable transfer belt (26b) having a smooth contact surface with the tape to which the tape adheres ( W) after the interstice of the shoe press. A method according to any one of claims 1 to 4, characterized in that the tape (W), which has been transferred from the roller press (9) to the shoe press (10), adheres to a felt Press (22) of the shoe press (10), whose press felt of the shoe press (10) carries the tape (W) into the interstice of the shoe press, with the assistance of blow boxes they generate partial vacuum or suction boxes (25), which are arranged in the loop of the last press felt (22) mentioned. A method according to any one of claims 1 to 5, characterized in that the belt (W) is transferred from the roller press (9) to the shoe press (10) with the aid of an intake suction roller ( 24), which is arranged in the loop of a press felt (22) of the shoe press (10), whose press felt (22) of the shoe press (10) carries the tape (W) inside the shoe press gap. A method according to claim 2, characterized in that the belt (W) is transported to the shoe press (10) to the gap of the shoe press enclosed between two press fittings (22, 26) of the shoe press (10) in a sandwich construction, in which at least one of the shoe lining showers is a press felt (22). A method according to claim 1 or 2, characterized in that the press felts (13, 15) of the interstitium of the double felt roller press comprise an upper felt of the press (13) and a lower felt of the press ( 15) and because the belt (W) is transported from the interstice of the roller press enclosed between the upper and lower felt of the press (13, 15) in a sandwich construction. A method according to claim 1, 4, 5 or 6, characterized in that the press felts of the interstitium of the double felt roller press comprise an upper felt of the press (13) and a lower felt of the press (15 ), because the shoe press (10) comprises two press fittings (22, 26) at least one of which is a felt of the press (22), because the belt (W) is transported from the interstitium of the roller press enclosed between the upper and lower press felt (13, 15) of the roller press (9) in a first sandwich construction, one of the upper and lower felt of the press being subsequently separated (15 or 13) outside the belt (W) which is transferred from the other of the upper and lower press felt of the roller press (9) to one of the press fittings (22 or 26) of the shoe press (10) with a closed section, and because then the belt (W) is transported to the gap of the shoe press enclosed between the press fittings (22, 26) of the shoe press (10) in a second sandwich construction. 10. A method according to any one of claims 1 to 9, characterized in that each of the press rollers (11, 12) of the roller press (9) has a water receiving capacity of 0.7 to 1, 8 dm3 / m2 of enveloping surface. 11. Paper or cardboard making machine for manufacture of high speed printing paper or cardboard, whose Printing paper or cardboard has a weight of 30 to 200 g / m2, the machine comprising a wet section (1), a section of press (2) and a drive section (3), whose section of Press (2) includes a roller press (9) that has a interstitium of the double felt roller press, and a press of shoes (10), which is located downstream of the press of rollers (9) and having an extended gap of the press of single felt or double felt shoes,

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at that the roller press (9) comprises two press rollers open offset deviation (11, 12) that form the interstice of the roller press in the middle, comprising each one of said two press rollers (11, 12) a surface envelope (42) of blind holes or grooves, articulated in shape rotating, a stationary beam (43) and a shoe member (44) disposed between said beam (43) and said envelope surface (42), said shoe member (44) comprising a plurality of shoes of sliding loaded hydraulically, in which said two press rollers (11, 12) are arranged in such a way that their shoe members (44) act against each other,

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and in which the machine is arranged to be driven at a speed of the belt of at least 1,200 m / min., with a linear load in the interstitium of the roller press ranging from 100 to 300 kN / m, in a preferred manner from 120 to 250 kN / m, and in the Shoe press gap varies from too much to 1,500 kN / m, in a preferred manner from 700 to 1,200 kN / m, and with a specific pressure in the gap of the roller press that ranges from 5 to 15 MPa, in a preferred manner from 8 to 11 MPa, and in the interstice of the shoe press varies from 4 to 13 MPa, in a preferred manner from 4 to 8 MPa, to obtain a dehydrated tape (W) with a dry solids content of at minus 35 percent, in a preferred way at least 38 percent, after the interstice of the roller press and at least 45 per one hundred after the gap of the shoe press.

12. A machine according to claim 11, characterized in that a suction roller (6, 47) and / or one or several blow boxes generating partial vacuum or suction boxes (17) are arranged after the interstice of the roller press in the loop of one of the press felts (15 or 13) of the interstitium of the double felt roller press, one of said press felts (15 or 13) acting as a transfer belt for the transfer of the belt (W) from the roller press (9) to the shoe press (10). 13. A machine according to claim 11, characterized in that the gap of the shoe press is double-felt and that a suction roller (28, 30) and / or one or more blow boxes that generate partial vacuum or suction boxes (29, 31) are arranged after the gap of the shoe press in the loop of one of the press felts (26 or 22) of the gap of the double felt shoe press, one of said press felts acting (26 or 22) as a transfer felt for transferring the belt (W) from the shoe press (10) to the drying section (3). 14. A machine according to claim 11, characterized in that the press nip shoe is individually felt and because other Press Fitting is passed through the press nip shoe, the other lining of the press being provided with shoes in the form of a waterproof transfer belt (26b) having a smooth surface to which the tape adheres after the gap of the shoe press. 15. A machine according to claim 14, characterized in that the waterproof transfer belt (26b) is arranged as a lower press fitting in the shoe press (10). 16. A machine according to any one of claims 11 to 15, characterized in that the blowing boxes (25) that generate partial vacuum are arranged in the loop of the press felt (22) of the shoe press (10), which bears the belt (W) in the shoe press (10) inside the gap of the shoe press, said blow boxes (2) being arranged in front of the gap of the shoe press. 17. A machine according to any one of claims 11 to 16, characterized in that an intake suction roller (24) is arranged in the shoe press (10) in the loop of a press felt (22) of the press shoes (10) that carry the tape (W) inside the shoe press, whose intake suction roller (24) is arranged to cooperate with one of the press felts (15 or 13) of the press gap of double-felt rollers, one of said felt of the press (15 or 13) of the felt of the double-felt roller press acting as a transfer belt for transferring the belt (W) from the roller press (9 ) to said press felt (22) of the shoe press (10). 18. A machine according to claim 12, characterized in that the shoe press (10) comprises two press fittings (22, 26), at least one of which is a felt of the press (22), the two fittings being arranged of the press (22, 26) to enclose the belt (W) between them in front of the gap of the shoe press to form a sandwich construction until the gap of the shoe press. 19. A machine according to claim 11 or 12, characterized in that the felt of the press (13, 15) of the interstitium of the double-felt roller press comprises an upper felt of the press (13) and a lower felt of the press (15) which are arranged to enclose the tape (W) between them from the interstice of the roller press to form a sandwich construction to a suction roller (6, 47) which is disposed within the loop of the upper felts and bottom of the press (15 or 13), which is arranged to transfer the tape (W) to the shoe press (10). 20. A machine according to claim 11, 14, 15, 16 or 17, characterized in that the felt of the interstitium press of the double felt roller dam comprises an upper felt of the press (13) and a lower felt of the press (15), because the shoe press (10) comprises two press fittings (22, 26), at least one of which is a press felt (22), because the upper and lower press felts (13, 15) of the roller press (9) are arranged to enclose the belt (W) between them from the interstice of the roller press to form a first sandwich construction to a suction roller (47) that is disposed within the loop of one of the upper and lower felt of the press (13 or 15), which is arranged to transfer the tape (W) to one of the fittings (22 or 26) of the shoe press (10), and because the fittings Press (22, 26) of the shoe press (10) are arranged to ignite Roll the tape (W) between them in front of the shoe press gap to form a second sandwich construction until the shoe press gap. 21. A machine according to any one of claims 11 to 20, characterized in that each of the open press rollers (11, 12) of the roller press (9) has a steel wrapping surface (42) with blind perforated holes or slots for receiving water that together have a volume per square meter of enveloping surface of 0.7 to 1.8 dm 3. 22. A machine according to claim 21, characterized in that the volume of grooves or holes is approximately 1.1 dm3 / m2 of envelope surface. 23. A machine according to claim 22, characterized in that at least one of the press rollers (11, 12) is grooved, the grooves having a width of approximately 0.5 mm and a depth of approximately 5 mm, the distance cc being between two adjacent grooves approximately 2.25 mm.