FI105573B - Paper machine, in particular paper dryer roll and paper machine dryer group - Google Patents

Description

105573

Paper machine, in particular paper dryer roll and paper machine dryer group

Vals för pappersmaskin, i synnerhet torkanordning 'för papper och torkgrupp för pappersmaskin 5

The invention relates to a roll of a papermaking machine, in particular to a paper drying apparatus, the roll comprising an axis on which the roll is adapted to rotate and a surface structure connected to the shaft by supports or the like, preferably more than 20%.

The invention also relates to a papermaking machine dryer assembly comprising two contact drying cylinders and at least one rotary roller, wherein the drying assembly utilizes a single wire thread wherein the paper web to be dried supported on the dryer and with a pivoting cylinder on the outer curve side, wherein at least one of the pivoting rollers of the drying group is an open roll having a surface structure of more than 10%, preferably more than 20%.

It is known in the prior art to use 25 double wire inlets and / or single wire in paper machine multi-cylinder dryers. In two wire wire dry. the ink cylinder groups have two wires that press one of the webs against the upper half and the other against the heated cylinder surfaces. Between the drying cylinder rows, generally horizontal rows, the web has free and unsupported draws in the twin wire feed, which is subject to fluttering, which can cause web breaks, especially in those stages of drying where the web is still relatively damp and consequently weak. Therefore, in the last few years, there has been an increasing use of said single-wire export, with each dryer-cylinder group having only one dryer wire, supporting the web 35 through the entire group such that the dryer wire presses the web against the the rolls remain on the outer side of the curve. Thus, in a single wire delivery, the drying cylinders are 2,105,573 outside the wire loop and the turning cylinders or rollers are inside it. In the so-called normal single-wire export groups, the drying cylinders are in the top row and the turning cylinders or rollers are in the bottom row and so-called. in rotated single-wire export groups, drying cylinders in Alari-5 and rotary cylinders or rollers in the top row.

In the prior art drying apparatuses, the dryer wire and paper web come from the previous dryer element, e.g., from a contact dryer dryer cylinder to a reversible suction cylinder or the like, in a common straight run, whereby a closing wedge is formed between the dryer wire and the surface of the latter suction cylinder. The movable dryer fabric and the suction cylinder surface tend to induce overpressure in said wedge space. This in turn causes a difference in pressure on the paper web supported by the dryer fabric, which tends to release the paper web from the dryer fabric, causing runnability problems, wrinkles and even web breaks. On the other hand, in order to improve the efficiency of the drying parts, there is a need to use more compact drying parts in which the contact drying cylinders and said suction cylinders are as close as possible. All these factors, together with increasing line speeds, increase the pressure problems of said inlet nip.

As is known in the art, the transfer of a paper web in a single-wire delivery from a pivoting cylinder to a contact drying cylinder generally takes place such that the web is supported on the wire by means of a blow box or a similar vacuum field. The applicant markets blower boxes under the trademark UNO-RUN-BLOW-BOX "and their operation is referred to in U.S. Patent 4,516,330 and U.S. Patent 65,460, respectively. These solutions provide a paper web to a drying cylinder 30 at a rotating suction cylinder of <1600 machine speeds.

Prior art solutions have also sought to overcome the problem of inlet nip pressure peak by means of a roller, roller 3 105573 sector suction and various types of suction boxes, and combinations of rollers and suction boxes which, however, have not been able to eliminate the pressure nozzle.

5 It is known in the prior art that a vacuum is sufficient to hold the web on the surface of the pivoting cylinder or roll to overcome the centrifugal force. This required pressure can be calculated using the equation 10 Pv x U2 P = ...........

r 15 p = pressure N / m2

Pv = web weight in kg / m2 U = peripheral speed m / s r = cylinder radius / m 20 Depending on machine speed and web weight, the pressure requirement is 100-200 Pa. Thus, the problem has been the control of overpressure on the inlet nip. Harmful overpressure can also be reduced by roll grooving and drilling. However, these measures have not substantially resolved the problems of inlet nip pressure.

25

In the related art, reference may be made to U.S. Patent 3,259,961, wherein the cell structure of the disclosed solution exerts an overpressure on the inlet nip because it has walls perpendicular to the rotational movement.

30

Reference may also be made, for example, to U.S. Pat.

It is an object of the present invention to further develop the above-described and similar techniques so that the problems caused by the export of said narrow wedge-shaped web to its inlet nip region are largely resolved.

The main object of the invention is to improve the propulsion in single wire delivery by solving the generation of harmful overpressure in the inlet nip.

It is also an object of the invention to provide a more compact drying machine for a paper machine.

To achieve the above and later objects, the paper drying apparatus roll according to the invention is essentially characterized in that the surface structure of the roll is slit open, so that as the roll rotates an air-absorbing effect is produced on the roll, thereby creating an air flow through the roll.

15

The drying group according to the invention, in turn, is essentially characterized in that the open roll is slit open so that the air flow passing through the wire passes through the slot open surface structure inside the roll and further discharges with the wire as the air flow through the open surface structure.

The roll of the invention has a slit open structure which prevents overpressure in the inlet nip. Both the surface structure of the roll and the inner structure of the roll are designed to be substantially open so that the flow of air with the wire is caused inside the roll and rotates there more slowly than the roll from the starting nip with the wire. The roll structure generates a strong air inflow as it rotates, thereby acting as a flow-through fan.

. . 30

The flow inside the roll is mainly due to the centrifugal force outflow in the opening nip. The pocket space, which conveniently opens to the air between the open, slot-like surface structure, develops an outward blowing effect, with consequently 35 air flowing inside the roll from the area of the closing nip. Air flows inside the roller at a clearly slower speed than the roller rotation speed, because the centrifugal force is prevented by the internal transparency of the roller, whereby the air inside the roller does not rotate the roller speed.

According to a preferred embodiment of the invention, the open structure 5 is achieved with a sheet-like surface structure and an interior open shape with a surface structure transparency of more than 10%, preferably more than 20%.

According to the invention, the roll is preferably used in the single-wire export area of a paper machine. Preferably, the roll according to the invention is substantially smaller in diameter 10 compared to many known rotary roller and cylinder applications, whereby it can be positioned close to contact drying cylinders and further allows sealing of the drying group to provide a very compact drying section. The roll according to the invention is also suitable for use as a paper guide roll 15, where the problem is the formation of an air layer between the roll surface and the paper.

According to the invention, in order to prevent overpressure of the pocket space area, a blow box or the like may be provided in connection with the roll, which prevents air from entering the pocket space. This can be accomplished by a blower-acting box or by a barrier seal, e.g. a passive box, the shape of which divides the free surface of the roll into two parts, i.e. outflow and inward flow.

In the following, the method according to the invention will be described in more detail with reference to the figures in the accompanying drawings, in which details the invention is not intended to be narrowly limited.

Fig. 1 schematically shows an embodiment of a roll 30 according to the invention in which the roll is provided with a suction.

Fig. 2 schematically shows another embodiment of a roll according to the invention.

Figure 3A shows an embodiment of a roller application according to the invention.

6 105573

Fig. 3B shows another embodiment of a roller application according to the invention in which a blow box is provided in connection with the roll in the pocket space.

Fig. 3C shows another embodiment of a roller application according to the invention, in which a passive box is arranged in connection with the roll in the pocket space.

Fig. 4A schematically shows the measurement results in connection with the arrangement according to the invention, showing a vacuum on a wire surface without a blow box.

Figure 4B schematically shows the measurement results in connection with the arrangement of the invention showing the vacuum at the inlet 15 of the wire under the blowing box.

Figures 5A-5B show an embodiment of a roll according to the invention.

Figures 6A-6C further show further possibilities for a roll according to the invention.

Fig. 7 schematically shows an arrangement for use with a roll according to the invention.

Fig. 8 schematically shows an embodiment of a roll according to the invention in one of its application.

According to Figure 1, the roller 10 according to the invention comprises an axis 11 and shaft pins 12. In the embodiment of the invention according to Figure 1, the roller 30 10 is provided with suction and the suction openings formed in the shaft 11 of the roller 10 are designated is denoted by reference numeral 20 and the suction space inside the shaft 11 by reference numeral 19. At the end 19A, the suction space 19 of the shaft 11 of the roll 10 is connected to a vacuum source. In accordance with the invention, the roll surface structure 35 is formed by forming a roll casing portion 13 in the form of disc spaced spaced spaced centered circular ring discs 18 connected to one another by means of a fastening bar 15.16, 17 through the ends of the arms 15, 16, 17; 16A, 17A. Thus, the roll structure 10 is very open because there is a space between each ring plate 18 as well as an open area 27 between the periphery 5 of the support members 14 and the inner periphery of the tire plates 18. The support pieces 14 connecting the ring plates 18 to each other the volume of the region 27 is 20-80%, preferably 40-70%, of the volume of the roll 10.

The support members 14 are disposed at each end of the shaft 11 and at appropriate intervals along the length of the roll so that the support bars 15A, 16A, 17A connected to the leg portions 15,16,17 of the support members 14 extend through all of the tire pieces 18. 10, which, mainly due to the strength factors 15 and 15, is provided with a shaft 11.

The embodiment of Fig. 2 corresponds to that of Fig. 1 and like parts refer to like numerals. However, in this exemplary embodiment of the invention, the roll 10 is not provided with a suction, whereby the shaft 11 is uniform and Figure 2 also shows the end pins 12 of each end of the shaft 11.

The diameter D of the roll 10 is 500-1500 mm, preferably 600-1000 mm, and the proportion of the open interior DS is 20-80%, preferably 40-70% of the roll 10. Of the 25 quays, D.Tel 10 has a surface texture transparency of more than 10%, preferably more than 20%.

Fig. 3A shows a roll according to the invention in a use application according to the invention as a rotating roll of a drying group applying single wire threading. The paper web W to be dried comes from the drying cylinder 30, whose rotation direction is indicated by the arrow S, supported by the wire 35 on the pivoting roll 10 being on its outer curve and the wire 35 being against the pivoting roll 10. The space 35 between the rollers 30,31 and the roller roller 10 and the wire 36 is referred to as a pocket space from the roll roll 10 and the web 35 to be dried.

The roll 10 according to the invention causes the airflow I 10 carried with the wire 35 to be strongly absorbed inside the roll 10 and discharged from the other side of the roll 10 as an air flow I2, leaving the pocket space T with the wire 35.

Fig. 3B shows an exemplary embodiment of the invention corresponding to Fig. 3A, in which a blow box 37 is inserted in pocket space T, whose blows are designated by reference P. This arrangement provides that substantially all of the pocket space T is underpressure.

Fig. 3C shows an embodiment of the invention corresponding to Fig. 3A, in which a passive box 39 is provided for dividing the air flows of the pocket space T and for depressurizing the pocket space T, which divides the free surface of the roll 10 into two parts.

15

As shown in Figures 3A-3C, the roll 10 according to the invention enables a very compact drying group. The ratio of the diameter D of the roll 10 to the diameter DC of the contact drying cylinder 31 is 1: 1 to 1: 4, preferably 1: 2 to 1: 3, whereby the roll 10 can be brought close to the drying cylinders 20 30.31.

Figure 4A is a schematic representation of experimental results when testing the arrangement of the invention in the installation of Figure 3A. The axis Y has a vacuum and the axis X represents the distance from the closing nip. Curves 25 45 and 46 illustrate vacuum on the wire surface. The solid curve 45 shows the test result at 1500 m / min and the dashed line 46 test result at 1800 m / min. As can be seen from the curves 45.46, the vacuum increases as the speed increases. In addition, the vacuum is higher near the closing nipple, indicating that the flow is directed from the roll nip 30 into.

Figure 4B is a schematic representation of test results when testing the arrangement of the invention in the installation of Figure 3B. The axis Y has a vacuum and the axis X represents the distance from the closing nip. Curves 35 41,42,43,44 illustrate the vacuum at the inlet surface of the wire under the blow box. The solid curve 41.43 shows the test result at 9105573 at 1500 m / min and the dashed 42.44 test result at 1800 m / min. Curves 41 and 42 illustrate a situation in which the blower box blowing was not turned on and curves 43 and 44 illustrate a situation in which the blower box blowing is on. Figure 4 shows that the vacuum? 5 pocket mode increases with speed, which is the opposite of standard roll and suction roll solutions.

Figures 5A-5B illustrate an embodiment of the invention in which the roll 10A of open structure is formed by longitudinal rods 10 or mesh 51 interconnected by spacer rings 52 and end rings 53 to provide an open space between the shaft 52 and the surface structure of support roll 54 .

Figures 6A-6C are schematic end views of various rollers according to the invention. The roller 10A of Fig. 6A is formed of discrete discs 57. The roller 10B of Fig. 6B is formed of lightened discs 57 of apertures 58. These disc structures 57 can be used as annular plates 18 of the rolls of Figures 1 and 2. a bent sheet tape 59 which may have a bending surface 59E as shown in Figure 7. In the embodiments shown in Figures 5A-6C, the roll 10A-10E has a diameter of 500 to 1500 mm, preferably 600 to 1000 mm and a transparency of more than 10%, preferably more than 20%.

Fig. 8 shows an arrangement corresponding to the embodiment of Fig. 3B in the single wire delivery of the drying section and in the screened area the vacuum area created by the roll 10 and the blow box 37 is marked in connection with the roll 10 and pocket space T. As can be seen from the figure, the same vacuum under the blow box 37 and inside the roll 10 is due to the open structure.

*

The invention has been described above with reference only to some preferred embodiments thereof, the details of which, however, are not intended to be narrowly limited. Many modifications and variations are possible within the scope of the inventive idea defined in the following claims.

Claims (13)

1 I A roll of a papermaking machine, in particular a paper drying apparatus, the roll (10,10A-10E) comprising an axis (11,52) on which the roll (10) is arranged to rotate and a surface structure (13) connected to the shaft. support members (14) or the like, in which the surface structure (13) of the roll (10) has a transparency of more than 10%, preferably more than 20%, characterized in that the surface structure of the roll (10) is slit open 10) an inlet air-absorbing action, whereby a flow of air is generated through the roller (10). Roll according to Claim 1, characterized in that the velocity of the air flow through the roll (10) is different from that of the roll (10). 15 Roll according to claim 1 or 2, characterized in that the inner structure of the roll (10) is formed as an open intermediate space (27) such that the length (DS) of the open portion (27) of the roll (10) is parallel to the roll (10). The ratio of roll (10) to diameter 20 (D) is 1:10 to 1: 1.5, preferably 1: 4 to 1: 2. Roll according to one of Claims 1 to 3, characterized in that the surface structure (13) of the roll (10) is formed by spaced spaced annular plates (18) which are arranged on the support rods (15A, 16A) arranged in connection with the support pieces (14). 17A) connected via a shaft (11) of the roll (10). Roll according to Claims 1 to 3, characterized in that the roll (10A) is formed so that the roll surface structure 30 (13) is formed by substantially longitudinally extending rods (51) which are connected to each other by support rings (52). which are connected to the shaft (52) of the roll (10) by end flanges (53). Roll according to one of the preceding claims, characterized in that the annular body (18) is formed by a disc (57) comprising a lightened portion (58). li 105573 Roll according to one of the preceding claims, characterized in that the surface structure (13) of the roll (10) is formed by a bent sheet band (59). Roll according to one of the preceding claims, characterized in that the roll has a diameter of 500 to 1500 mm, preferably 600 to 1000 mm. Roll according to one of the preceding claims, characterized in that the interior space (19) of the shaft (11) of the roll (10) is arranged as a suction space such that one end (19A) of the shaft (11) of the roll (10) (11) the jacket (20) is provided with suction openings (21). A papermaking machine drying group comprising two contact drying cylinders (30,31) and at least one rotary roller (10), wherein a single wire thread is applied in the drying group, wherein the drying web (W) supported by the drying wire (35) is adapted to travel on its knees 30) on the swivel roll (10) and further on the drying cylinder (31) such that with the contact drying cylinders (30,31) the paper web (W) is between the cylinder surface and the drying wire (35) and on the outer side of the swivel cylinder (10) 10) at least one is an open roll (10) having a surface structure (13) having a transparency of more than 10%, preferably more than 20%, characterized in that the open roll (10) is slit open so that the air flow with the wire (35) (I2) passes through the slit open surface structure (13) of the roll (10) inside the roll (10) and is further discharged with the wire (35) as an air flow (I2) into the open roll (10) n through the surface structure (13). 30 10 105573 Paper machine drying group according to Claim 10, characterized in that a blow box (37) is provided in the pocket space (T) between the drying cylinders (30,31), the turning roller (10) and the wire (35). T) is substantially depressurized in its entirety. 12 105573 Paper machine drying group according to Claim 10 or 11, characterized in that a passive box (39) is arranged on its pockets (T), dividing the free surface of the roll (10) into the inflow area and the outflow area. 5 Paper machine drying group according to one of Claims 10 to 12, characterized in that the ratio of the diameter (DC) of the drying cylinder (30,31) to the diameter of the roll (10) is 1: 1 to 4: 1, preferably 2: 1 to 3: 1. 10 • · 13 105573