WO2011076251A2

WO2011076251A2 - Runnability component

Info

Publication number: WO2011076251A2
Application number: PCT/EP2009/067684
Authority: WO
Inventors: Seppo YÖMAA; Hannu Kokkala; Nenad Milosavljevic; Kalle Muhonen; Kalle Helenius
Original assignee: Metso Paper, Inc.
Priority date: 2009-12-21
Filing date: 2009-12-21
Publication date: 2011-06-30
Also published as: WO2011076251A3

Abstract

A runnability component for a paper or board machine for ensuring a web run over a fabric supported run in a gap from cylinder (1) or roll (3) to a second cylinder (5) or roll of the paper or board machine comprises a main portion (7) for transferring a fluid sucked from the gap and discharging the same or for transferring a fluid from an outside of the runnability component for blowing next to the gap, wherein, in a runnability component, a main axis of the main portion (7) extends in a cross machine direction. Furthermore, the runnability component has an extension portion (9). The extension portion (9) has a seal (11, 13) arranged to seal the gap between moving surfaces of the one cylinder (1) or roll (3) or the fabric there between, and the second cylinder (5) or roll and an edge of the extension portion (9). Furthermore, the main portion (7) supports the extension portion (9) and the interior of the main portion is connected to the interior of the extension portion via at least one fluid passage in a wall of the main portion.

Description

RUNNABILITY COMPONENT

Description

The invention pertains to a runnability component for a paper or board machine for ensuring a web run over a fabric supported run in a gap from one cylinder or roll to a second cylinder or roll of the paper or board machine, and to a paper or board machine comprising such a runnability component .

In paper or board machines and especially in a dryer section of such a machine, a web is alternatingly guided about cylinders and/or rolls which are provided in a plural number of rows, e.g. two rows. Between each cylinder or roll and the subsequent cylinder or roll, a gap exists in which the web is transferred from the one cylinder or roll to the subsequent cylinder or roll. This process is also known as "web run over a fabric supported run". In order to avoid a web break, the web is generally supported by a fabric guided about some or all of the cylinders or rolls in meandering path. Thus, the web is moving about the same speed than the fabric supporting the web within one drying group. A drying group comprises cylinders and rolls, which are arranged within one loop of the same drying wire.

Between the different drying groups an appropriate draw can be used to compensate an elongation or shrinking of the web .

To ensure the web run from one roll or cylinder to the subsequent roll or cylinder, runnability components are known. Such runnability components are used for sucking the air existing in the gap for facilitating the detachment of the fabric and the web from the one cylinder or roll.

Furthermore, due to this suction, a disadvantageous bending of the fabric and the web in the gap between the surfaces of the cylinders or rolls can be avoided.

In common arrangements, with machine speeds over 1600m/min and/or an underpressure of more than 2kPa, the distance between a cylinder and the subsequent roll or vice versa should be lower than 20mm. If the machine speed is lower than 1200m/min and/or an underpressure is lower than IkPa, the distances can be between 30mm and 50mm.

With these parameters bending of the fabric or wire is kept minimal and a contact between the fabric or wire and the seal can be avoided. Furthermore, if the web detaches too soon, that is, over 100mm earlier from the cylinder, some drying capacity is lost because of long conventional run from the cylinder to the roll. Thus, it is difficult to ensure a sufficient negative pressure to eliminate forces such as underpressure forces of the opening gap or adhesion forces between the web and the cylinder for ensuring that the web is transferred to the supporting fabric.

The term "next to the gap" used above as well as in the description and the claims means one or more locations close to the gap where the air blown outwards against or to the direction of movement of the nearby moving surface is capable to generate an underpressure.

Document EP 0 427 217 A2 discloses a drying section for drying a web moved with high transport velocity. The drying section comprises a first row of cylinders and a second row of rolls. Each roll is located below and between two of the cylinders. Furthermore, a fabric is alternatingly guided in a meandering path about the cylinders and rolls,

respectively. In a space between two neighboring cylinders and the roll provided below and between the two cylinders, a runnability component is arranged. The section of the runnability component has a polygon shape in order to cover the space between the fabric coming from the first cylinder, the roll and the fabric leading to the second cylinder .

Because of the polygonal cross section shape of the runnability components according to the prior art, the installation space between the cylinders and the roll has to be quite large. Therefore, the fabric supporting the web travels a large distance through the gap, that is, from the point where it is detached from the cylinder to the point where it is contacting the roll as well as from the point where it is detached from the roll to the point where it is contacting the next cylinder. Therefore, measures must be taken to prevent bending of the fabric supporting the web as well as to ensure that the web is adhesively maintained at the cylinder but is transferred to the fabric. Because of the large travelling distance of the web, a large effort with respect to material, suction force/blowing force etc. is necessary to conduct these measures.

There is need for a runnability component requiring a reduced installation space.

According to the invention, a runnability component for a paper or board machine for ensuring a web run over a fabric supported run in a gap from cylinder or roll to a second cylinder or roll of the paper or board machine comprises a main portion for transferring a fluid sucked from the gap and discharging the same to an outside of the runnability component or for transferring a fluid from an outside of the runnability component for blowing next to the gap, wherein, in a runnability component, a main axis of the main portion extends in a cross machine direction. Furthermore, the runnability component has an extension portion which is arranged to extend in the gap for sucking the fluid from the gap or blowing the fluid next to the gap, respectively. Alternatively or additionally, the extension portion can support a seal holder portion having one or more seal holders. The extension portion has a seal arranged to seal the gap between moving surfaces of the one cylinder or roll or the fabric there between, and the second cylinder or roll and an edge of the extension portion. Furthermore, the main portion supports the extension portion. Alternatively, if a one piece solution is provided, the main portion can include the extension portion. The interior of the main portion is connected to the interior of the extension portion via at least one fluid passage in a wall of the main portion.

Preferably, the main portion's cross section has a round shape such as a circular shape or an elliptic shape.

Because of the round shape of the main portion's cross section, the main portion has sufficient rigidity properties preventing a bending of the main portion which extends in the cross machine direction. Furthermore, the main portion can be a self-supporting structure and no measures for supporting the runnability component in the cross machine direction are required. Furthermore, vibrations occurring due to the suction or blowing of the fluid can be satisfyingly encountered.

Preferably, at least the extension portion or the main portion or the seal holder portion can be made of an extruded profile. Alternatively or additionally, at least two extruded profiles can be combined, where one of the extruded profiles forms the extension portion and/or the seal holder portion, and the second profile forms the main portion and/or the extension portion. It is even possible to use one combined extruded profile forming all three portions in one piece.

Providing extruded profiles advantageously facilitates an adjusting process of the extension portion and the seal holder portion which is necessary to ensure a suitable distance between seals and the corresponding moving surfaces of the cylinders, rolls and web, respectively. By combining such extruded profiles, the adjusting process can be made between the main portion and the extension portion, or it can be even possible to omit such an adjusting process .

Advantageously, the main portion can be made of a pipe or of an extruded profile or of a bent structure or of a combination thereof. The runnability component can be made of the same material throughout to avoid bending, although the basic structure can be a combination of different materials. Especially aluminum or an aluminum alloy can be a suitable material.

Thereby, an economic production and installation of the runnability component is ensured. Especially, bending of the main portion can be avoided with this rigid, light weight structure. Therefore, the distance of the seals to the fabric and moving surfaces of the cylinders or rolls, respectively, can be maintained.

Especially, if the main portion and the extension portion are below 29 inches, i.e. 737 mm, they can be extruded in one piece, which also facilitates the faster manufacturing of the runnability component. Advantageously, the end surfaces of the extension portion and of the main portion in the cross machine direction are closed by end covers.

Thus, it is not necessary to cover the full installation space by the runnability component, but merely the cross section of the main portion and the extension portion needs to be covered. Thus, the length of a side sealing against the respective moving surfaces of the cylinder, roll or web, respectively, can be minimized.

Advantageously, the end covers for the main portion and the extension portion can be provided separate from each other. Furthermore, advantageously, the shape of the respective end covers substantially can correspond to that of the cross section of the main portion and to that of the cross section of the extension portion inclusive that of the cross section of the gap between the cylinders or rolls and/or the fabric.

The advantages achieved by this arrangement correspond to those described above, that is, there is no necessity to cover the whole installation space between the respective cylinders and rolls.

Furthermore, advantageously, the end covers can be opened in order to access the interior of the runnability element.

Due to this arrangement, maintenance and cleaning

operations are facilitated.

Furthermore, advantageously, the end covers of the extension portion can be provided with fast locks. This arrangement enables a fast opening of the end covers of the extension portion which can be necessary in case of a malfunction, replacement of the seals or of the fabric or any necessity to enter the gap.

Furthermore, advantageously, the extension portion and/or the end covers of the extension portion can be made at least partly of a transparent material.

This enables an in-situ inspection of the runnability component, the seals and the fabric, while the paper of board machine is in operation.

Furthermore, advantageously, at least one of the seals is provided with the extension portion. In this case, advantageously, if the runnability component is movable in horizontal and/or vertical directions, the seal can be removed together with the runnability component. Thereby, replacing the seal or the fabric is facilitated.

Advantageously, the seal can be made of Teflon.

Furthermore, advantageously, the cross section of the main portion has a circular shape having a diameter between 150mm to 420mm or preferably from 250mm to 350mm or at best from 280mm to 320mm. Preferably the wall thickness of the main portion and/or the extension portion is between 3mm and 8mm, most preferably it is 4mm of aluminum or aluminum alloy.

Advantageously, the extension portion can enable a flow speed of 30m/s to 45m/s in the foremost section openings. However, with wider machines even higher flow speeds can be achieved. Thereby, the negative pressure distribution is more even in the cross machine direction. Advantageously, the runnability component can be a suction box or a blow box.

Furthermore, advantageously, the cross sectional shape of the main portion can be circular or elliptic.

A runnability component as described above is

advantageously incorporated in a dryer section of a paper or board machine. In the dryer section a row of cylinders and the row of rolls is provided, wherein a web supported by a fabric is guided in a meandering path past the cylinders and the rolls.

Furthermore, advantageously, the rolls can be reversing rolls and/or grooved rolls and/or vacuum rolls and/or perforated rolls.

Because of the smooth surface of a perforated roll, the use of such a perforated roll improves the sealing properties. Thus, an accurate setting and maintaining of a negative pressure e.g. in the gap or in other pressure zones is possible. Furthermore, the possibility of pressure fluctuations in the gap is minimized, leading to a reduced energy consumption for maintaining the set negative pressure .

Furthermore, in the paper or board machine, the distance between the first cylinder or roll and the subsequent second cylinder or roll can correspond to the distance between the extension portion and the moving surfaces of the cylinders or rolls.

Furthermore, advantageously, a paper or board machine can have openable cover parts arranged to cover the installation space between the end faces of the extension portion and of the main portion. Thereby, it is possible to generate a negative pressure in the whole installation space between the fabric and the second cylinder or roll. Therefore, it is possible to suck a fluid through the second cylinder or roll into the main portion if the second cylinder or roll is e.g. a perforated roll.

The use of a perforated roll together with the openable cover parts enables the setting of different negative pressure zones. That is, in the gap a large negative pressure can be generated in order to ensure that the web is detached from the first cylinder and is kept at the fabric supporting the web for its transfer to the roll, while a low negative pressure zone can be generated at the circumference of the perforated roll. Thus, since it is ensured that the web is kept at the roll while being guided there around, the web is easily transferred to the next cylinder .

According to the invention, the distance between a cylinder and the subsequent roll or vice versa between a roll and the subsequent cylinder can be between 5 and 50 mm, preferably between 10 and 30 mm.

Presently preferred embodiments of the invention will be described in connection with the attached drawings, in which :

Fig. 1 is a schematic cross sectional view of a runnability component according to a first embodiment of the invention, which is installed in a dryer section of a paper or board machine ; Fig. 2 is a schematic cross sectional view of a runnability component according to a second embodiment of the

invention, which is installed in a dryer section of a paper or board machine;

Fig. 3 is a schematic cross sectional view of a runnability component according to a third embodiment of the invention, which is installed in a dryer section of a paper or board machine ;

Fig. 4 is a schematic cross sectional view of a runnability component according to a fourth embodiment of the

invention, which is installed in a dryer section of a paper or board machine.

Fig. 1 is a schematic cross sectional view of a runnability component according to a first embodiment of the invention. The runnability component is installed in a dryer section of a paper or board machine. In the dryer section cylinders are arranged in a row and rolls are arranged such that each roll is located below and between two adjacent cylinders. A fabric supporting a web to be dried is alternatingly guided about a cylinder, the subsequent roll, the next cylinder etc. in a meandering path.

In Fig. 1, reference signs 1 and 5 are assigned to a first and a second cylinder of the above mentioned row of cylinders, while reference sign 3 is assigned to a roll in the above mentioned row of rolls.

A gap is formed between the cylinder 1 and the subsequent roll 3, and a second gap, not shown in the figures, is formed between the roll 3 and the subsequent cylinder 5. In the gap a run over of the web W supported by the fabric from the cylinder 1 to the roll 3 takes place. For ensuring the run over, a runnability component is installed in the space between the cylinders 1, 5 and the roll 3.

The runnability component comprises a main portion 7, the cross section of which has a circular shape extending in a cross machine direction. An extension portion 9 is attached to the main portion 7 with bolts 25. The extension portion 9 extends into the gap. The main portion 7 is self- supported and also supports the extension portion 9.

In a wall segment of the main portion 7, at which the extension portion 9 is attached, holes 23 indicated by dotted lines are provided. Via these holes 23 an air in the gap can be sucked via the extension portion 9 and the holes 23 to the main portion 7 from where it is transferred to the outside.

In order to maintain a sufficient negative pressure generated by the suction of the air, at the end parts of the extension portion 9, which reach into the gap, a seal 11 and a double seal 13 are arranged. Double seal 13 is provided with a seal holder 15 being a seal holder portion according to the invention. Seal holder 15 can be made by an extruded profile. The seal 11 extends in cross machine direction and seals the gap against the moving surface of the roll 3. The double seal 13 is arranged against the fabric supporting the web , which is being guided about the cylinder 1. Thus, the space between the fabric supporting the web W and the roll 3 is completely sealed in the cross machine direction. For maintaining the negative pressure, end covers 17 corresponding to the shape of the gap between the fabric supporting the web W and the surface of the roll 3 and the seals 11 and 13 are provided at the end surfaces of the extension portion in cross machine direction. The end covers 17 are made of a transparent material which allows an in-situ inspection of the components in the gap such as the seals 11, 13 and of the fabric supporting the web .

According to the embodiment, seal holder 15 has a round shape and is partly surrounded by the extension portion 9. In order to maintain the structural components in right measures, a high degree of accuracy is needed. Thus, when using extruded profiles e.g. for the seal holder 15 and/or the extension portion 9, adjusting of the seals is simplified.

For maintenance, the end covers 17 can be opened to enable access to the gap. For this purpose, fast locks 21 and a hinge 19 are provided.

In the embodiment, the diameter of the circular main portion 7 is between 280 and 320mm and, the main portion 7 is a pipe provided in one piece.

In the following description of the further embodiments of the invention, merely those components will be described which are different to the first embodiment.

In the second embodiment, as shown in Fig. 2, the main portion is made of two profiles 6 and 8, each having the shape of a half circle in the cross machine direction. The two profiles each have a flange at both of their ends which flanges are used to connect the two bent profiles 6 and 8 by a nut and bolt combination 27.

Furthermore, the extension portion 9 is attached to the profile 6 of the main portion 7 by means of a shape joint with sliding means such as rails. At the end of the extension portion 9 extending into the gap, one seal 12 extending to both moving surfaces is provided. The one end of the seal 12 is in abutment with the surface of the roll 3 while the other end of the seal 12 is in abutment with the fabric supporting the web W, which is guided about the roll 1.

It is noted that the term "in abutment" with regard to the seals and the moving surfaces throughout the whole application is to be understood as a situation where the seal is almost in contact with the respective moving surface next to the seal. The distance between the seal and the surface is between Omm and 3mm, preferably between 1mm and 2mm. This distance is set and measured when the machine is not running.

Fig. 3 shows a third embodiment of the invention. In this embodiment, the main portion 7 consists of one profile which is bent into a circular shape in its width direction. Each of the ends of the profile in the width direction is provided with a flange. The flanges are connected by a nut and bolt connection 29.

At the end of the extension portion 9, extending into the gap, double sealing 14 is arranged similarly to the arrangement in the second embodiment. In both embodiments mentioned above, the sealings can as well be separated for each surface to avoid a thermal elongation of the sealings.

Furthermore, in the third embodiment, a perforated roll 43 is provided instead of the roll 3 of the previous

embodiments. Between the main portion 7, the extension portion 9 and the roll 43, additional end plates 31 and 37 are provided for covering the end surface between the perforated roll 43, the extension portion 9 and the main portion 7.

Furthermore, non-illustrated holes are provided in the section of the main portion 7 which faces the profiled roll 43. Because of the perforated roll 43, in addition to the air sucked from the gap via a extension portion 9 and the holes 23 into the main portion 7, air is sucked from the perforated roll 43 via the space between the surface of the perforated roll 43, the main portion 7 and the extension portion 9 into the main portion 7. For maintaining the negative pressure in the space between the surface of the perforated roll 43 facing the extension portion 7 and the extension portion 7, a seal 39 is provided which seals this space against the area between the perforated roll 43 and the second cylinder 5.

Thus, because of the end plates 31 and 37, the seal 39 and the perforated roll 43, in addition to the negative pressure zone in the gap, a second negative pressure zone acting in the circumference of the perforated roll 43 is generated. Thus, due to the first negative pressure zone corresponding to the gap, it is ensured that the web W supported by the fabric is kept at the fabric and is reliably transferred from the cylinder 1 to the perforated roll 43 in the gap, and, furthermore, due to the second negative pressure zone, corresponding to the circumference of the perforated roll 43, it is ensured that the web W is maintained at the perforated roll 43. Especially, the absolute value of the negative pressure in the first negative pressure zone (gap) is higher than that of the second negative pressure zone (circumference of the perforated roll 43) . For a simplified access of the space between the

runnability component and the roll 3, the end plates 31 and 37 are attached to the machine frame with hinges 33 and 35, respectively. Thus, the end covers 31 and 37 can be opened for the sake of access, cleaning or maintenance.

Furthermore, the end covers 31 and 37 can be made at least partly of a transparent material which enables in-situ inspection while the paper or board machine is in operation .

It is noted that the embodiments shown in Figs. 1 to 3 do not limit the scope of the invention and neither show a limitation with regard to the combination of components used, but, in contrast, it is possible to reasonably combine components from one of the embodiments with those of one or more of the other embodiments in accordance with the intended use.

An example for such a possible combination of components known from the first to third embodiments is shown in Fig. 4. Here, the main portion 7 corresponds to the main portion 7 of Fig. 2. Furthermore, the extension portion 9 is attached as is the case in Fig. 2 via a shape joint with sliding means 28. However, in Fig. 4, the seal 11 and the double seal 13 provided in the seal holder 15 of Fig. 1 are provided instead of the seal 12.

Furthermore, for example it is also possible to use the perforated roll 43 together with cover plates 31, 37 and the seal 39 in the embodiments of Figs. 1, 2 and 4.

Additionally or alternatively, cover plates can fill the whole pocket space between the cylinders and the turning roll though the size of the runnability component is as presented in the figures. The materials used for the components of the runnability component can be a metal such as aluminum or suitable plastic materials. Especially, the profiles of the main portion and of the extension portion can be formed by extrusion molding. Furthermore, it is possible to form the main portion and the extension portion in one piece.

With a tight and compact fitting of the cylinders and rolls or with wider machines, i.e. machines having a width wider than 6m, the shape of the runnability component can be triangular or even match the pocket space between the cylinders and the turning roll. In such a case there exists also an extension portion and sealing arrangements according to the invention, which allows a precise fitting of these key components to a very limited space.

Alternatively, when forming the main portion and the extension portion in more than one piece, apart from attaching the extension portion to the main portion by nuts and bolts, joining methods such as welding or plastics welding can be employed.

The diameter of the circular cross section of the extension portion can be between 150 and 420mm, preferably between 250mm and 350mm, and most preferably between 280 to 320mm. Thus, the less space than with commonly known runnability components is required for the installation of the runnability component according to the invention.

Therefore, the distance between the cylinders and the rolls, that is, the size of the gap, is reduced, for which reason sagging of the fabric supporting the web as well as excessive energy consumption for maintaining the negative pressure in the gap at the desired level is avoided. Furthermore, due to the fixed shapes of the main portion and the extension portion, working time for the installation as well as problems with misalignments and resulting errors are prevented.

Thus, while the invention has been described by way of example on the basis of presently preferred embodiments, the scope of the invention is defined by the attached claims .

Claims

1. Runnability component for a paper or board machine, for ensuring a web run over a fabric supported run in a gap from one cylinder or roll to a second cylinder or roll of the paper or board machine , comprising

a main portion for transferring a fluid sucked from the gap and discharging the same, or for transferring a fluid from an outside of the runnability component for blowing next to the gap, wherein, in the runnability component, a main axis of the main portion extends in a cross machine direction, and

an extension portion being configured to be arranged to extend into the gap and/or for supporting a seal holder portion,

characterized in that

the main portion supports the extension portion or includes the extension portion, and the interior of the main portion is connected to the interior of the extension portion via at least one fluid passage in a wall of the main portion.

2. Runnability component according to claim 1, wherein at least the extension portion or the main portion or the seal holder portion is made of an extruded profile.

3. Runnability component according to claim 2, wherein at least two extruded profiles are combined, one of the extruded profiles forming the extension portion and/or the seal holder portion, and the second profile forming the main portion and/or the extension portion. . Runnability component according to any of the preceding claims, wherein the main portion is made of a pipe or of an extruded profile or a bent structure or of a combination thereof.

5. Runnability component according to any of the preceding claims, wherein the end surfaces of the extension portion and of the main portion in the cross machine direction are closed by end covers .

6. Runnability component according to claim 5, wherein separate end covers are provided for the main portion and for the extension portion, and the shape of the respective end covers substantially corresponds to that of the cross section of the main portion and to that of the cross section of the extension portion inclusive that of the cross section of the gap between the cylinders or rolls and/or the fabric.

7. Runnability component according to claim 5 or 6, wherein the end covers are openable for accessing an interior of the Runnability component.

8. Runnability component according to claim 7, wherein the end covers of the extension portion are provided with fast locks for fast opening.

9. Runnability component according to any of the preceding claims, wherein at least one seal is provided with the extension portion, which seal is configured to seal a gap formed between an edge of the extension portion and moving surfaces of the respective cylinders and/or rolls .

10. Runnability component according to any of the preceding claims, wherein the at least one seal provided with the extension portion as well as surfaces of the end covers designed to be close to or in contact with the moving surfaces of the cylinders and/or rolls are made of Teflon .

11. Runnability component according to any of the preceding claims, wherein the main portion has a circular shape having a diameter in a range from 150mm to 420mm or preferred from 250mm to 350mm or most preferred from 280mm to 320mm.

12. Runnability component according to claim 11, wherein the wall thickness of the main portion and/or the extension portion is 4mm, and the material of one or both of the portions is aluminum or an aluminum alloy.

13. Runnability component according to any of the preceding claims, wherein the extension portion is configured to enable a flow speed of 30 to 45 m/s .

14. Paper or board machine including a dryer section comprising a row of cylinders and a row of rolls, wherein a web supported by a fabric is guided in a meandering path past the cylinders and the rolls, comprising a runnability component according to any of claims 1 to 15, which is arranged between one of the cylinders and the respective subsequent roll.

15. Paper or board machine according to claim 14, wherein the cylinders are dryer cylinders and/or the rolls are reversing rolls and/or grooved rolls and/or vacuum rolls and/or perforated rolls.

16. Paper or board machine according to claims 14 or 15, wherein the distance between the first cylinder or roll and the subsequent second cylinder or roll corresponds to the distance between the extension portion and the moving surfaces of the cylinders or rolls.

17. Paper or board machine according to any of claims 14 to 16, wherein openable cover parts are arranged to cover the space between the end faces of the extension portion and of the main portion and the second cylinder or roll, to additionally enable sucking of the fluid through the second cylinder or roll into the main portion, and fluid passages are provided in a wall portion of the main portion, which faces the roll.