CA1243197A - Method and apparatus for guiding a paper web from the press section to the drying section - Google Patents
Method and apparatus for guiding a paper web from the press section to the drying sectionInfo
- Publication number
- CA1243197A CA1243197A CA000446945A CA446945A CA1243197A CA 1243197 A CA1243197 A CA 1243197A CA 000446945 A CA000446945 A CA 000446945A CA 446945 A CA446945 A CA 446945A CA 1243197 A CA1243197 A CA 1243197A
- Authority
- CA
- Canada
- Prior art keywords
- web
- drying
- drying wire
- wire
- guide roll
- 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.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F2/00—Transferring webs from wet ends to press sections
Abstract
Abstract of the Disclosure A method for guiding the paper web from the press section of a paper machine to the drying section is described.
In the method, the web is guided, supported on the drying wire, at least through the first group of drying cylinders or through the initial end of this group. A fetching roll or a suction roll is located close to the smooth-faced centre roll of a closed press section. The drying wire of the first cylinder group of the drying section is passed over the fetching roll or equivalent. The web is passed from the roll of the press section as an open draw onto the drying wire running over the fetching roll. Within the run between the fetching roll and the first drying cylinder, on the opposite side of the drying wire to that supporting the web, several air jets are blown at a speed that is higher than the speed of the drying wire, the initial direction of the jets being substantially the same as the direction of running of the drying wire at that position. By means of this blowing of air, air is ejected out of the space between the drying wire and the walls of members that produce the jets of air. As a result, the web is held closely in contact with the drying wire and the web stretching necessary to detach the same from the press section section roll is significantly decreassed.
In the method, the web is guided, supported on the drying wire, at least through the first group of drying cylinders or through the initial end of this group. A fetching roll or a suction roll is located close to the smooth-faced centre roll of a closed press section. The drying wire of the first cylinder group of the drying section is passed over the fetching roll or equivalent. The web is passed from the roll of the press section as an open draw onto the drying wire running over the fetching roll. Within the run between the fetching roll and the first drying cylinder, on the opposite side of the drying wire to that supporting the web, several air jets are blown at a speed that is higher than the speed of the drying wire, the initial direction of the jets being substantially the same as the direction of running of the drying wire at that position. By means of this blowing of air, air is ejected out of the space between the drying wire and the walls of members that produce the jets of air. As a result, the web is held closely in contact with the drying wire and the web stretching necessary to detach the same from the press section section roll is significantly decreassed.
Description
, ~2~3~9~ .
ETHOD AND APPARATUS FOR GUIDIN~ A PAPE~ ~IEB FROM
THE PR~SS SECTIO~ TO THE DRYING SECTION
_ The present invention is concerned with a method for guidin~ a paper web from the press section of a paper-5 making machine to the drying section, in which method the webis guided while supported on the drying wire at least through the first group of drying cylinders or through the initial end of this group.
The invention is additionally concerned with an appa-10 ratus for applying the method in accordance with the invention.
After the press section, the web prepared in a papermachine is very weak, and a major proportion of the breaks of the web occur OIl the run of the web between the press section and the first drying cylinder. Other problematic poin's in 15 this respect are, for example, the spaces between drying-groups, i.e., in general, all such runs of the web where the web runs unsupported.
The last roll in the press section is usually a rock roll, from which it is difficult to detach the web, 20 because the web tends to follow the very smooth face of the rock roll.
An example of a press section in which the method and apparatus in accordance with the invention can be applied is the applicant's SYM-PRESS (TM) press sec~ion, which, as 25 is known, comprises a closed roll combination consisting of ~our press rolls, wherein the first nip formed between a hollow-faced roll and a suction roll is prcvided with two felts. The second, single-felt nip is formed between the suction roll and the centre roll of the press section. The 30 centre roll of the press section is a smooth-faced rock roll, in connection with which the last, i.e. third, nip of the press is formed, which nip is provided with a felt of its own.
The web is detached from the smooth face of the rock roll by elongation of the web.
~4 ~ ~3~
In currently practised methods, the web is elongated or stretched extensively, by up to 2 to 3 per cent, in connection with its detaching from the rock roll. Such an extensive elongation is necessary in order to control the fluttering of the web occurring between the press section and the drying section. A paper machine should, however, be run with minimum differences in speeds in order that the web should not lose its strength. A high degree of elongation has to be paid for later and causes difficulties, e.gO, in connection with coating of the paper.
In respect of the prior-art technology related to the present invention, reference is made to the publication by Scapa-Porrit Ltd., "Felts and fabrics. Sheet flutter in the dryer part", wherein a method is suggested in which the detaching of the web from the rock roll takes place by means of a suction roll and in which the web is passed while supported all the way from the press onto the first drying cylinder. It would be preferable to have no need for the detrimental elongation at all. In practice, this prior-art method has, however, proved more problematic than expected.
Suction alone is not sufficient to detach the web from the rock roll, the web does not remain in contact with the drying wire without additional support, and the closing nip forme~
by the first drying cylinder with the wire causes wrinkles in particular at the sides of the web. If a felt is used instead of a drying wire, problems encountered have been rewetting of the paper web as well as contamination of the suction rolls and reconditioning of the felt.
Recently, attempts have been made to reduce the number of suction rolls in paper-making machines, and even their entire elimination has been aimed at, for they are of high cost, require an abundance of energy and maintenance, and they are components that readily break down. The threading of the end of the web is also difficult when the web is detached by means of a suction roll, for, during `"` ~2~3~
threading, the suction roll sucks air from the area that is not covered by the web, and no suction effect is generated on the tail end of the web.
In the present invention, attempts are made to 5 provide such a support of the web in which no detrimen-tal fluttering occurs and in which the elongation of the web can be decreased significantly.
In accordance with one aspect of the present invention, there is provided a method for guiding a 10 fibrous web from a press section to a drying section, comprising the steps of passing the web from the press section in an open draw onto a drying wire passing about a guide roll; and urging the we~ and drying wire against each other as the drying wire passes from the guide roll to the drying section by ejecting gas out of blowing means on a side of the drying wire opposite a side supporting the web in a direction substantially parallel to a running direction of the drying wire and web and at a speed greater than a running speed of the drying wire in order to generate negative pressure in a space between the blowing means and the drying wire.
The present invention also includes novel apparatus for carrying out the method aspect of the invention. Accordingly, in another aspect of the invention, there is provided apparatus for guiding a fibrous web from a press section to a drying section, comprising a guide roll adapted to guide the web passing from the press section onto a drying wire from the drying seation passing about the guide roll; and means for urging the web and drying wire against one another as the web is passed to the drying section, the urging means disposed between the guide roll and the drying section in a running direction of the web and wire; the guide roll constituting means for passing the web in an open draw from the press section onto the drying wire;
and the urging means comprising means for generating a negative pressure in a space adjacent a side of the drying wire opposite a side contacting the web, to urge the web and drying wire wire against each other; and the B
negative pressure generating means comprising at least one blowing box having gas discharge means extending substantially over an entire width of the web, the blowing box directing a gas stream through the gas discharge means in a direction sustantially parallel to the running direction of the web and supporting drying wire, and at a speed greater than a running speed of the drying wire, to create negative pressure between the blowing box and the drying wire to thereby urge the web and drying wire against one another.
Below, the invention will be described in detail, and by way of illustration, with refeence to the Figures of the accompanying drawings, wherein:
Figure 1 schematically shows the running of the web through a SYM-PRESS (TM) press section and the supporting of the run in accordance with one embodiment of the invention after the press section as well as the guiding of the web to the initial end of the drying section; and Figure 2 schematically shows the area of a paper machine between the press section and the drying section, wherein the method in accordance with one embodiment the invention is employed for supporting the web, on a scale larger than that of Figure 1.
With reference to Figure 1, an example of a press section will be described initially, after which press section the method and arrangement in accordance with the invention can be applied advantageously. It is, however, emphasized that the invention is not restricted only to the use in connection with a press section and drying section of the kind illustrated in Figure 1.
In Figure 1, the paper web W arries in the press section on the fabric 14. The fabric 14 may be, e.g., a pick-up fabric, which transfers the web from the forming wire on a pick-up roll (not shown) onto the fabric 14. The fabric 14 runs through the first nip N
in the press section. The first nip Nl is formed between a lower roll 10 having a hollow face 10' and a B
L3~9~
4a suction roll 13 provided with a suc~ion zone 13 ~. The first nip Nl is a two-felt nip, and its lower fabric is felt 12, which runs as guided by guide rolls 11. In the nip N1, the other felt is the fabric 14, which also acts as a press fabric in the second nip N2. The web W
departs from the felt 14 after the second nip N2, at which time it has adhered to the smooth face 15' of the centre roll 15 of the press section. The centre roll 15 is usually a rock roll, whose diameter is advantageously larger than the diameters of the other press rolls. The centre roll 15 and the press roll 16 form the third nip N3. Through the third nip N3, a press felt 18 of its own runs, which is guided by guide rolls 17 ` 5 ~2~3~97 The web Wl, which has adhered to the smooth face 15' of the rock roll 15, is detached and then is supported by means of the method and arrangement in accordance with the invention, which method and arrangement mainly comprise a fetching roll 22, 5 a drying wire 23 running over tne fetching roll 22, and blow Doxes 25a, 25b, 25c. Figure 1 shows tne initial end of tne drying section, i.e. the cylinders 20 of the upper row and the cylinder 20' of the lower row, the we~ W Deing supported by the drying wire 23 on tne runs between tne said cylinders.
As was mentioned above, the web W remains by means of adhesion forces in contact on the smooth face 15' of the rock roll 15. The web W is detached from the rock roll 15 by extending the web. The fetching roll 22 is located so close to the rock roll 15 that fluttering of 15 the web W on its free run Wl can hardly take place. As a result, an elongation of only about 1 to 1.5 per cent is sufficient to detach the web W from the face 15' of the roll 15. From the fetching roll 22, the web W is passed, support~d on the wire 23, onto the first drying cylinder
ETHOD AND APPARATUS FOR GUIDIN~ A PAPE~ ~IEB FROM
THE PR~SS SECTIO~ TO THE DRYING SECTION
_ The present invention is concerned with a method for guidin~ a paper web from the press section of a paper-5 making machine to the drying section, in which method the webis guided while supported on the drying wire at least through the first group of drying cylinders or through the initial end of this group.
The invention is additionally concerned with an appa-10 ratus for applying the method in accordance with the invention.
After the press section, the web prepared in a papermachine is very weak, and a major proportion of the breaks of the web occur OIl the run of the web between the press section and the first drying cylinder. Other problematic poin's in 15 this respect are, for example, the spaces between drying-groups, i.e., in general, all such runs of the web where the web runs unsupported.
The last roll in the press section is usually a rock roll, from which it is difficult to detach the web, 20 because the web tends to follow the very smooth face of the rock roll.
An example of a press section in which the method and apparatus in accordance with the invention can be applied is the applicant's SYM-PRESS (TM) press sec~ion, which, as 25 is known, comprises a closed roll combination consisting of ~our press rolls, wherein the first nip formed between a hollow-faced roll and a suction roll is prcvided with two felts. The second, single-felt nip is formed between the suction roll and the centre roll of the press section. The 30 centre roll of the press section is a smooth-faced rock roll, in connection with which the last, i.e. third, nip of the press is formed, which nip is provided with a felt of its own.
The web is detached from the smooth face of the rock roll by elongation of the web.
~4 ~ ~3~
In currently practised methods, the web is elongated or stretched extensively, by up to 2 to 3 per cent, in connection with its detaching from the rock roll. Such an extensive elongation is necessary in order to control the fluttering of the web occurring between the press section and the drying section. A paper machine should, however, be run with minimum differences in speeds in order that the web should not lose its strength. A high degree of elongation has to be paid for later and causes difficulties, e.gO, in connection with coating of the paper.
In respect of the prior-art technology related to the present invention, reference is made to the publication by Scapa-Porrit Ltd., "Felts and fabrics. Sheet flutter in the dryer part", wherein a method is suggested in which the detaching of the web from the rock roll takes place by means of a suction roll and in which the web is passed while supported all the way from the press onto the first drying cylinder. It would be preferable to have no need for the detrimental elongation at all. In practice, this prior-art method has, however, proved more problematic than expected.
Suction alone is not sufficient to detach the web from the rock roll, the web does not remain in contact with the drying wire without additional support, and the closing nip forme~
by the first drying cylinder with the wire causes wrinkles in particular at the sides of the web. If a felt is used instead of a drying wire, problems encountered have been rewetting of the paper web as well as contamination of the suction rolls and reconditioning of the felt.
Recently, attempts have been made to reduce the number of suction rolls in paper-making machines, and even their entire elimination has been aimed at, for they are of high cost, require an abundance of energy and maintenance, and they are components that readily break down. The threading of the end of the web is also difficult when the web is detached by means of a suction roll, for, during `"` ~2~3~
threading, the suction roll sucks air from the area that is not covered by the web, and no suction effect is generated on the tail end of the web.
In the present invention, attempts are made to 5 provide such a support of the web in which no detrimen-tal fluttering occurs and in which the elongation of the web can be decreased significantly.
In accordance with one aspect of the present invention, there is provided a method for guiding a 10 fibrous web from a press section to a drying section, comprising the steps of passing the web from the press section in an open draw onto a drying wire passing about a guide roll; and urging the we~ and drying wire against each other as the drying wire passes from the guide roll to the drying section by ejecting gas out of blowing means on a side of the drying wire opposite a side supporting the web in a direction substantially parallel to a running direction of the drying wire and web and at a speed greater than a running speed of the drying wire in order to generate negative pressure in a space between the blowing means and the drying wire.
The present invention also includes novel apparatus for carrying out the method aspect of the invention. Accordingly, in another aspect of the invention, there is provided apparatus for guiding a fibrous web from a press section to a drying section, comprising a guide roll adapted to guide the web passing from the press section onto a drying wire from the drying seation passing about the guide roll; and means for urging the web and drying wire against one another as the web is passed to the drying section, the urging means disposed between the guide roll and the drying section in a running direction of the web and wire; the guide roll constituting means for passing the web in an open draw from the press section onto the drying wire;
and the urging means comprising means for generating a negative pressure in a space adjacent a side of the drying wire opposite a side contacting the web, to urge the web and drying wire wire against each other; and the B
negative pressure generating means comprising at least one blowing box having gas discharge means extending substantially over an entire width of the web, the blowing box directing a gas stream through the gas discharge means in a direction sustantially parallel to the running direction of the web and supporting drying wire, and at a speed greater than a running speed of the drying wire, to create negative pressure between the blowing box and the drying wire to thereby urge the web and drying wire against one another.
Below, the invention will be described in detail, and by way of illustration, with refeence to the Figures of the accompanying drawings, wherein:
Figure 1 schematically shows the running of the web through a SYM-PRESS (TM) press section and the supporting of the run in accordance with one embodiment of the invention after the press section as well as the guiding of the web to the initial end of the drying section; and Figure 2 schematically shows the area of a paper machine between the press section and the drying section, wherein the method in accordance with one embodiment the invention is employed for supporting the web, on a scale larger than that of Figure 1.
With reference to Figure 1, an example of a press section will be described initially, after which press section the method and arrangement in accordance with the invention can be applied advantageously. It is, however, emphasized that the invention is not restricted only to the use in connection with a press section and drying section of the kind illustrated in Figure 1.
In Figure 1, the paper web W arries in the press section on the fabric 14. The fabric 14 may be, e.g., a pick-up fabric, which transfers the web from the forming wire on a pick-up roll (not shown) onto the fabric 14. The fabric 14 runs through the first nip N
in the press section. The first nip Nl is formed between a lower roll 10 having a hollow face 10' and a B
L3~9~
4a suction roll 13 provided with a suc~ion zone 13 ~. The first nip Nl is a two-felt nip, and its lower fabric is felt 12, which runs as guided by guide rolls 11. In the nip N1, the other felt is the fabric 14, which also acts as a press fabric in the second nip N2. The web W
departs from the felt 14 after the second nip N2, at which time it has adhered to the smooth face 15' of the centre roll 15 of the press section. The centre roll 15 is usually a rock roll, whose diameter is advantageously larger than the diameters of the other press rolls. The centre roll 15 and the press roll 16 form the third nip N3. Through the third nip N3, a press felt 18 of its own runs, which is guided by guide rolls 17 ` 5 ~2~3~97 The web Wl, which has adhered to the smooth face 15' of the rock roll 15, is detached and then is supported by means of the method and arrangement in accordance with the invention, which method and arrangement mainly comprise a fetching roll 22, 5 a drying wire 23 running over tne fetching roll 22, and blow Doxes 25a, 25b, 25c. Figure 1 shows tne initial end of tne drying section, i.e. the cylinders 20 of the upper row and the cylinder 20' of the lower row, the we~ W Deing supported by the drying wire 23 on tne runs between tne said cylinders.
As was mentioned above, the web W remains by means of adhesion forces in contact on the smooth face 15' of the rock roll 15. The web W is detached from the rock roll 15 by extending the web. The fetching roll 22 is located so close to the rock roll 15 that fluttering of 15 the web W on its free run Wl can hardly take place. As a result, an elongation of only about 1 to 1.5 per cent is sufficient to detach the web W from the face 15' of the roll 15. From the fetching roll 22, the web W is passed, support~d on the wire 23, onto the first drying cylinder
2~ 20 or onto a corresponding lead-in cylinder.
Be~ween the fetching roll 22 and the first drying cylinder 20, the web W is supported by means of the ~ethod in accordance with the present invention, which method will be described in more det~il in the 25 fol.~owing. Out of the blow boxes 25a,25b,25c located at the side of the wire 23, air jets S1 are blown sub-stantially in the direction of running of the wire 23, the speed of the said air jets being substantially higher than the speed of the wire 23. As is well known, 30 a moving wire 23 carries air along with it. If the area from which the wire 23 takes air with it can be sealed, a negative pressure is produced in that area.
In the method in accordance with the present invention, the sealing is performed by means of blowing of air.
35 Since the speed of the jets S1 is higher than the speed of the wire 23, an ejection effect is produced, which intensifies the negative pressure caused by the pumping on the wire 23. The sealing of the area of negative pressure in the other direction takes place ~ Z~319~
by means of air jets S2. The direction of these jets is the same as the direction of a tangent imagined at the fetching roll 22.
As a result of the negative pressure produced between the blow boxes 25a, 25b, 25c and the wire 23(~), air tends to *low through the wire 23. Since the web W
is substantially impervious to air, the web W2 is drawn tightly into contact with the wire 23, and no detrimen-tal fluttering occurs. Under these circumstances, the blow boxes stabilize the running of the wire 23 and of the web W2 between the roll 22 and the cylinder 20.
In Figure 2, there are illustrated three blow boxes 25a, 25b, 25c one after the other. Depending on the geometry between the press section and the drying section, there may be one or several blow boxes. The blow boxes each have a planar bottom face 28, which is located at a distance ~ from the opposite drying wire 23. The distance ~ is preferably within the range of about 10 to 25 mm. At both ends of the planar bottom wall 28 of the blow boxes 2sa, 25b, 25c, there are located nozzle slots 29, by means of which the blow jets Sl and S2 described above are generated. The downstream nozzle slot 29' of the last nozzle box 25c is located substantially at the position at which the drying wire 23 and the web W achieve contact with the first drying cylinder 20.
The fetching roll 22 may also be arranged as a suction roll, and the suction zone 22 ~ of the roll 22 is shown in broken lines in Figure 2. The suction zone 22 ~ is, however, by no means indispensible, but, if required, by its means it is possible to ensure that the web W remains on the wire 23 as it changes its direction within the sector ~ of the fetching roll 22. As a fetching roll, it is also possible to use a grooved roll, in whose grooves a slight negative pressure is formed within the area coxresponding to the suction zone 22 ~ of a suction roll.
B
~2~3~7 6a Generation of detrimental positive pressures in the chutes Kl, K2 and K3 shown in Figure 2 can be prevented by means of the method and arrangement suggested in the applicant's Canadian Patent No.
1,184,377, and for this purpose the air jets S3 of the blow boxes B
9~
26a and 26b are directed opposite to the direction of movement of the wire 23 or web W and of the roll 22, whereby the ejection effect of the jets S3 prevents generation of detrimental positive pressures.
The detaching of the web W from the smooth face 15' of the rock roll 15 may also be performed by means of a suction roll. The method and arrangement in accordance with our invention are also suitable for supporting the web in such case.
In summary of this disclosure, the present invention provides an improved method and apparatus for effecting transfer of a paper web from the press section to the ~rying section of a paper making machine.
Modifications are possible within the scope of this 15 invention.
Be~ween the fetching roll 22 and the first drying cylinder 20, the web W is supported by means of the ~ethod in accordance with the present invention, which method will be described in more det~il in the 25 fol.~owing. Out of the blow boxes 25a,25b,25c located at the side of the wire 23, air jets S1 are blown sub-stantially in the direction of running of the wire 23, the speed of the said air jets being substantially higher than the speed of the wire 23. As is well known, 30 a moving wire 23 carries air along with it. If the area from which the wire 23 takes air with it can be sealed, a negative pressure is produced in that area.
In the method in accordance with the present invention, the sealing is performed by means of blowing of air.
35 Since the speed of the jets S1 is higher than the speed of the wire 23, an ejection effect is produced, which intensifies the negative pressure caused by the pumping on the wire 23. The sealing of the area of negative pressure in the other direction takes place ~ Z~319~
by means of air jets S2. The direction of these jets is the same as the direction of a tangent imagined at the fetching roll 22.
As a result of the negative pressure produced between the blow boxes 25a, 25b, 25c and the wire 23(~), air tends to *low through the wire 23. Since the web W
is substantially impervious to air, the web W2 is drawn tightly into contact with the wire 23, and no detrimen-tal fluttering occurs. Under these circumstances, the blow boxes stabilize the running of the wire 23 and of the web W2 between the roll 22 and the cylinder 20.
In Figure 2, there are illustrated three blow boxes 25a, 25b, 25c one after the other. Depending on the geometry between the press section and the drying section, there may be one or several blow boxes. The blow boxes each have a planar bottom face 28, which is located at a distance ~ from the opposite drying wire 23. The distance ~ is preferably within the range of about 10 to 25 mm. At both ends of the planar bottom wall 28 of the blow boxes 2sa, 25b, 25c, there are located nozzle slots 29, by means of which the blow jets Sl and S2 described above are generated. The downstream nozzle slot 29' of the last nozzle box 25c is located substantially at the position at which the drying wire 23 and the web W achieve contact with the first drying cylinder 20.
The fetching roll 22 may also be arranged as a suction roll, and the suction zone 22 ~ of the roll 22 is shown in broken lines in Figure 2. The suction zone 22 ~ is, however, by no means indispensible, but, if required, by its means it is possible to ensure that the web W remains on the wire 23 as it changes its direction within the sector ~ of the fetching roll 22. As a fetching roll, it is also possible to use a grooved roll, in whose grooves a slight negative pressure is formed within the area coxresponding to the suction zone 22 ~ of a suction roll.
B
~2~3~7 6a Generation of detrimental positive pressures in the chutes Kl, K2 and K3 shown in Figure 2 can be prevented by means of the method and arrangement suggested in the applicant's Canadian Patent No.
1,184,377, and for this purpose the air jets S3 of the blow boxes B
9~
26a and 26b are directed opposite to the direction of movement of the wire 23 or web W and of the roll 22, whereby the ejection effect of the jets S3 prevents generation of detrimental positive pressures.
The detaching of the web W from the smooth face 15' of the rock roll 15 may also be performed by means of a suction roll. The method and arrangement in accordance with our invention are also suitable for supporting the web in such case.
In summary of this disclosure, the present invention provides an improved method and apparatus for effecting transfer of a paper web from the press section to the ~rying section of a paper making machine.
Modifications are possible within the scope of this 15 invention.
Claims (18)
1. A method for guiding a fibrous web from a press section to a drying section, comprising the steps of passing the web from the press section in an open draw onto a drying wire passing about a guide roll;
and urging the web and drying wire against each other as the drying wire passes from the guide roll to the drying section by ejecting gas out of blowing means on a side of the drying wire opposite a side supporting the web in a direction substantially parallel to a running direction of the drying wire and web and at a speed greater than a running speed of the drying wire in order to generate negative pressure in a space between the blowing means and the drying wire.
and urging the web and drying wire against each other as the drying wire passes from the guide roll to the drying section by ejecting gas out of blowing means on a side of the drying wire opposite a side supporting the web in a direction substantially parallel to a running direction of the drying wire and web and at a speed greater than a running speed of the drying wire in order to generate negative pressure in a space between the blowing means and the drying wire.
2. The method of claim 1, which additionally comprises suctioning the web onto the drying wire passing about the guide roll.
3. The method of claim 1, additionally comprising blowing gas in a direction substantially parallel to a tangent of the guide roll, to enhance generation of negative pressure in the space on the side of the drying wire opposite the side supporting the web.
4. The method of claim 3, comprising the additional step of blowing air out of a chute formed between the guide roll and the drying wire.
5. The method of claim 4, comprising the additional steps of blowing air out of a second chute formed between the guide roll and the drying wire, and out of a third chute formed between the web and the drying wire passing around the guide roll.
6. The method of claim 2, comprising stretching the web from about 1 to 1.5% in the running direction thereof as the web is passed in the open draw from the press section onto the drying wire passing about the guide roll.
7. Apparatus for guiding a fibrous web from a press section to a drying section, comprising a guide roll adapted to guide the web passing from the press section onto a drying wire from the drying section passing about said guide roll; and means for urging the web and drying wire against one another as the web is passed to the drying section, said urging means disposed between said guide roll and the drying section in a running direction of the web and wire;
said guide roll constituting means for passing the web in an open draw from the press section onto the drying wire: and said urging means comprising means for generating a negative pressure in a space adjacent a side of the drying wire opposite a side contacting the web, to urge the web and drying wire wire against each other; and said negative pressure generating means comprising at least one blowing box having gas discharge means extending substantially over an entire width of the web, said blowing box directing a gas stream through said gas discharge means in a direction sustantially parallel to the running direction of the web and supporting drying wire, and at a speed greater than a running speed of the drying wire, to create negative pressure between the blowing box and the drying wire to thereby urge the web and drying wire against one another.
said guide roll constituting means for passing the web in an open draw from the press section onto the drying wire: and said urging means comprising means for generating a negative pressure in a space adjacent a side of the drying wire opposite a side contacting the web, to urge the web and drying wire wire against each other; and said negative pressure generating means comprising at least one blowing box having gas discharge means extending substantially over an entire width of the web, said blowing box directing a gas stream through said gas discharge means in a direction sustantially parallel to the running direction of the web and supporting drying wire, and at a speed greater than a running speed of the drying wire, to create negative pressure between the blowing box and the drying wire to thereby urge the web and drying wire against one another.
8. The apparatus of claim 7, in which said guide roll is a suction roll having a suction zone over which the drying wire passes.
9. The apparatus of claim 7, wherein said gas discharge means are constituted by at least one nozzle slot or apertures.
10. The apparatus of claim 9, in which said negative pressure generating means comprises a plurality of blowing boxes, each box provided with a respective nozzle slot and a side facing the drying wire and extending substantially parallel to the running direction of the drying wire between said guide roll and the drying section.
11. The apparatus of claim 10, in which said negative pressure generating means comprises three blowing boxes successively disposed in the running direction of the drying wire and web, with the sides facing the drying wire being disposed in substantially the same plane.
12. The apparatus of claim 10, in which each of said blowing boxes comprises an additional nozzle slot, said additional nozzle slots extending over substan-tially the entire width of the web and constituting means for enhancing negative pressure generation between said blowing boxes and the drying wire.
13. The apparatus of claim 12, in which one of said blowing boxes is disposed in a vicinity of said guide roll and constitutes means for ejecting air out of a chute formed between said guide roll and the drying wire.
14. The apparatus of claim 12, in which one of said blowing boxes is disposed adjacent a drying cylinder in the drying section.
15. The apparatus of claim 11, in which the sides of said blowing boxes facing the drying wire are disposed at a distance of about 10 to 25 mm from the drying wire.
16. The apparatus of claim 7, in which said guide roll constitutes means for extending the web from about 1 to about 1.5% in the running direction thereof, as the web passes in the open draw from the press section onto the drying wire.
17. The apparatus of claim 13, additionally comprising means for ejecting air from a second chute formed between said guide roll and the drying wire, and from a third chute formed between the web and drying wire passing around said guide roll.
18. The apparatus of claim 17, in which said means for ejecting air out of the second and third chutes, comprises a blowing box disposed in the second chute and directing a gas stream in a direction substantially opposite to the running direction of the drying wire;
and a blowing box disposed in the third chute and directing a gas stream in a direction substantially opposite to the running direction of the web.
and a blowing box disposed in the third chute and directing a gas stream in a direction substantially opposite to the running direction of the web.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI830422 | 1983-02-07 | ||
| FI830422A FI67107C (en) | 1983-02-07 | 1983-02-07 | FOER FARANDE OCH ANORDNING FOER LEDANDE AV PAPPERSBANAN FRAON PRESSPARTIET TILL TORKPARTIET |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1243197A true CA1243197A (en) | 1988-10-18 |
Family
ID=8516726
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000446945A Expired CA1243197A (en) | 1983-02-07 | 1984-02-07 | Method and apparatus for guiding a paper web from the press section to the drying section |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH0635717B2 (en) |
| CA (1) | CA1243197A (en) |
| DE (1) | DE3400939A1 (en) |
| FI (1) | FI67107C (en) |
| SE (1) | SE461045B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5551171A (en) * | 1993-08-23 | 1996-09-03 | Sulzer-Escher Wyss Gmbh | Winding device for a fiber web |
| US5792318A (en) * | 1996-11-18 | 1998-08-11 | Mancini; Ralph | Method to stabilize sheet between press section and dryer section of a paper-making machine |
| US6260287B1 (en) | 1997-08-08 | 2001-07-17 | Peter Walker | Wet web stability method and apparatus |
| WO2016094087A1 (en) * | 2014-12-11 | 2016-06-16 | Georgia-Pacific Consumer Products Lp | Active web spreading and stabilization shower |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI67901C (en) * | 1983-10-03 | 1987-07-20 | Valmet Oy | FOERFARANDE OCH ANORDNING I TORKPARTIET I EN PAPPERSMASKIN VID STYRNING AV BANANS SPETS. |
| FI69332C (en) * | 1984-03-02 | 1986-01-10 | Valmet Oy | ANORDNING I TORKNINGSPARTIET AV EN PAPPERSMASKIN |
| FI69144C (en) * | 1984-05-04 | 1985-12-10 | Valmet Oy | ANORDINATION IN THE PAPER MACHINE WITH A STANNING OF BANANS SPETSDRAGNINGSBAND |
| US4970805A (en) * | 1987-02-13 | 1990-11-20 | Beloit Corporation | Transfer apparatus for transferring a tail of a web |
| US4875976A (en) * | 1988-09-27 | 1989-10-24 | Beloit Corporation | Transfer apparatus from press section to drying section |
| FI113973B (en) * | 1999-12-02 | 2004-07-15 | Metso Paper Inc | Method and apparatus for supporting a web |
| DE10212368A1 (en) * | 2002-03-20 | 2003-10-02 | Voith Paper Patent Gmbh | Paper industry drum assembly transfers carton or paper web from a smooth rotating drum to a lead suction drum |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1245278B (en) * | 1962-11-14 | 1967-07-20 | Escher Wyss Gmbh | Device for transferring a paper web in paper machines |
| JPS4735762U (en) * | 1971-05-08 | 1972-12-20 | ||
| US3874997A (en) * | 1973-03-21 | 1975-04-01 | Valmet Oy | Multiple cylinder drier in a paper machine |
| FI752585A (en) * | 1975-09-16 | 1977-03-17 | Valmet Oy | |
| FI65460C (en) * | 1980-12-12 | 1984-05-10 | Valmet Oy | FOER FARANDE OCH ANORDNING VID PRESS- ELLER TORKPARTIET I EN PAPERSMASKIN |
| DE3236576C2 (en) * | 1982-10-02 | 1988-03-24 | J.M. Voith Gmbh, 7920 Heidenheim | Air guide box for the dryer section of a paper machine |
-
1983
- 1983-02-07 FI FI830422A patent/FI67107C/en not_active IP Right Cessation
-
1984
- 1984-01-13 DE DE19843400939 patent/DE3400939A1/en active Granted
- 1984-02-03 SE SE8400556A patent/SE461045B/en not_active IP Right Cessation
- 1984-02-07 CA CA000446945A patent/CA1243197A/en not_active Expired
- 1984-02-07 JP JP59019558A patent/JPH0635717B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5551171A (en) * | 1993-08-23 | 1996-09-03 | Sulzer-Escher Wyss Gmbh | Winding device for a fiber web |
| US5792318A (en) * | 1996-11-18 | 1998-08-11 | Mancini; Ralph | Method to stabilize sheet between press section and dryer section of a paper-making machine |
| US6260287B1 (en) | 1997-08-08 | 2001-07-17 | Peter Walker | Wet web stability method and apparatus |
| WO2016094087A1 (en) * | 2014-12-11 | 2016-06-16 | Georgia-Pacific Consumer Products Lp | Active web spreading and stabilization shower |
| US9670616B2 (en) | 2014-12-11 | 2017-06-06 | Georgia-Pacific Consumer Products Lp | Active web spreading and stabilization shower |
Also Published As
| Publication number | Publication date |
|---|---|
| SE8400556L (en) | 1984-08-08 |
| FI830422A0 (en) | 1983-02-07 |
| SE8400556D0 (en) | 1984-02-03 |
| SE461045B (en) | 1989-12-18 |
| FI67107B (en) | 1984-09-28 |
| FI67107C (en) | 1985-01-10 |
| DE3400939A1 (en) | 1984-08-09 |
| FI830422A (en) | 1984-08-08 |
| JPH0635717B2 (en) | 1994-05-11 |
| DE3400939C2 (en) | 1991-08-14 |
| JPS59150195A (en) | 1984-08-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |