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. Furthermore, instead of sucking the air, there is also a possibility to generate an underpressure (negative pressure) in the gap by blowing air next to the gap such that an underpressure is generated in the gap.

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.

Therefore, in order to reliably ensure that a negative pressure can be generated and maintained in the gap, the runnability component is provided with seals which seal the area of the gap against the environment. Since these seals are in abutment against moving surfaces of the fabric or against moving surfaces of the rolls or cylinders, for sealing the gap against the environment, a periodical replacement of the seals is required. Additionally, the necessity to replace the fabric also arises periodically.

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.

For the reasons mentioned above, it is necessary to detach the seals from the fabric or the moving surface of the roll/cylinder. Fig. 1 shows a technology known by the applicant, in which a runnability component has a main portion 101 and an extension portion 103 extending into a gap formed between the running surfaces of a cylinder 121 and a roll 123. Incidentally, in Fig. 1, as well as in the other figures, merely relevant sections of the cylinders and rolls near a runnability component are shown, to avoid unnecessary illustrations .

The extension portion is provided with a seal 105 being in abutment with the running surface of the roll 123, and with seals 107 being in abutment against a fabric supporting a web on the other side, which is guided along the surface of the cylinder 121. The seals 107 are held by a round shaped seal holder 108 made from an extruded profile and being partly surrounded by extension portion 103. Thus, appropriate positioning of the seals is facilitated. A cover plate 109 serves to separate the gap against the environment in cross machine direction.

Thus, by sucking the air from the gap, since the gap is sealed against the environment by the seals 105, 107 and separated against the environment in cross machine direction by the cover plates 109, a negative pressure in the gap is caused. Due to this negative pressure, the detachment of the web from the surface of the cylinder is ensured.

For maintenance purpose, that is, to either replace the seals 105, 107 or the fabric, a seal support 111 supporting the seals 107 and having a circular cross section, can be rotated about its center axis extending in the cross machine direction. By rotating the seal support 111, the seals 107 are detached from the fabric and it is possible to replace the seals 107 or the fabric. However, due to limited working space between the cylinder 121 and the seal support 111, replacing the seals as well as the fabric is quite cumbersome.

Furthermore, replacing the seal 105 is also challenging, because the seal 105 must be replaced in its operating position, that is, while it is in abutment against the surface of the roll 123.

Therefore, after the replacement of the seals and/or the fabric has been carried out, functional troubles may arise with these components. Furthermore, some adjustments to pressure levels and positions of sealings may be needed to ensure the runnability and sealing function.

Thus, there is need for 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, in which components abutting against moving surfaces of the paper or board machine can easily and reliably be replaced, and where a good sight to the above mentioned components and the working area is enabled.

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 one 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. A main axis of the main portion extends in a cross machine direction. Furthermore, the runnability component has an extension portion designed to be arranged to extend into the gap for sucking the fluid from the gap. In the extension portion there is a seal arranged to seal the gap between moving surfaces of the one cylinder or roll, a fabric there between and the second cylinder or roll and an edge of the extension portion.

According to the invention, the runnability component has moving means which are arranged to accomplish that the runnability component or the extension portion or a combination thereof are movable in machine length and/or height directions to attach or detach the seal to/from the moving surfaces of the fabric, cylinders or rolls, respectively .

Since the whole runnability component or merely the extension portion or merely the seals attached to the extension portion are movable in machine length and/or height directions, when detaching the seals from the moving surfaces, the whole space between the respective cylinder or roll and a neighboring cylinder or roll may be used for moving the runnability component. Thereby, a large space sufficient for a reliable replacement operation occurs and the problems arising from a limited operation space for replacing the fabric or the seal can be avoided. Due to the moving it is even possible to safely change the seals while the machine is running. This advantageously reduces the down time of the machine when there is no need to stop the drying section. Furthermore, the seals can be fitted against two moving surfaces simultaneously by merely controlling the movement of the runnability component. Advantageously, the moving means can have an axis of rotation being parallel to the main axis of the main portion, that is, in cross machine direction. Thus, the runnability component, the extension part or the seals attached to the extension part or a combination thereof can be moved along an arc shaped moving path. Preferably, the radius of the arc more or less corresponds to the radius of the roll below.

Furthermore, advantageously, the moving means can have at least one arm which is arranged at end portions of the main portion. Thereby, the main portion is supported via a joint or a hinge coupling one of the arm's ends and the main portion .

In the arrangement described above, the extreme positions of the runnability component are maintained due to the runnability component's own weight. One the one side, in a replacement position with the seals being detached, this reduces an accidental movement during the replacement of the fabric and/or the seals, on the other side, in an operating position with the seals in abutment with the fabric and/or the surfaces of the cylinders or rolls, this ensures a uniform alignment along the whole cross machine direction. The moving means are connected between the sides so that the runnability component is moved with the moving device in the one side of the component.

Advantageously, the one arm can be connected to a base portion via a second joint or a hinge provided at the other of the arm's ends.

Furthermore, advantageously, the main portion can be supported by two arms, each of the arms having a j oint or a hinge at each of its respective ends . Furthermore, advantageously, the moving means can have a base portion supporting the main portion. The base portion can be connected to a machine frame.

Furthermore, advantageously, the base portion can be movable in directions being orthogonal to the main axis of the main portion, that is, orthogonal to the cross machine direction. Preferably the main direction of the movement is out of the gap and from the fabric, but the runnability component's distance to the turning roll may increase less.

Furthermore, advantageously, the base portions can include sliding surfaces which enable a movement of the base portion in directions lying orthogonally to the main axis of the main portion, that is, orthogonally to the cross machine direction. For causing the movement for instance pneumatic means, hydraulic means, rod and pinion or other suitable means can be used.

Furthermore, the extension portion can be made of a flexible material. Thereby, it can be prevented that a possible interference of the extension portion and the cylinders or rolls during the movement causes a malfunction or a damage of the fabric, or surfaces of the cylinders and/or rolls.

Furthermore, advantageously, the end surfaces of the extension portion and of the main portion in the direction of the main axis of the main portion are closed by end covers . These end covers can be completely opened or can be provided with openable doors for enabling an access, e.g. for maintenance . Furthermore, advantageously, the runnability component can be a suction box or a blow box.

According to the invention, furthermore, a runnability component as described above can be arranged in a paper or board machine including a dryer section consisting of a row of cylinders and a row of rolls, in which a web is guided in a meandering path past the cylinders and the rolls on the surface of a moving fabric. In such a machine, the runnability component is arranged in a space between two adjacent cylinders and the respective roll and fabric in between .

Furthermore, the runnability component can be disposed in a free space which is formed between two adjacent cylinders and a roll arranged below in between the two cylinders with the meandering fabric.

Advantageously, in the above described paper or board machine, the space formed between the end faces of the cylinders, the roll and the runnability component can be covered by an end plate.

Furthermore, advantageously, the end plate can be movable in a machine height direction and/or a machine width direction. Thus, it is possible to access the space between the two adjacent cylinders and the respective roll in between .

Furthermore, advantageously, the end plate can be covered with the moving means to enable the movement of the runnability element. Furthermore, advantageously, the cylinders can be dryer cylinders and/or the rolls can be reversing rolls and/or grooved rolls and/or vacuum rolls and/or perforated rolls.

Furthermore, advantageously, in a state in which the seal is attached to the moving surfaces of the first cylinder of the two cylinders and the roll or the fabric, respectively, a distance between the runnability component and the second of the two cylinders corresponds to the distance between the first cylinder and the roll plus a moving distance of the runnability element. These dimension properties ensure a sufficient space for the replacement of the seals and/or the fabric in a maintenance position of the runnability element, the extension portion or the seals attached to the extension portion, respectively.

In the following it is assumed that the fabric supporting the web W is at least guided in a meandering path about a first cylinder in a first row, a first roll in a second row and a second cylinder in the first row, for explaining certain dimensions of the runnability component in relation to a paper or board machine in which the runnability component is installed. The gap is formed between the first cylinder and the first roll.

However, it is noted that instead of the first and second cylinders rolls can be provided, instead of the roll another cylinder can be provided. Furthermore, there can be merely rolls or merely cylinders be provided.

Advantageously, the minimum moving distance can correspond to the distance between the first cylinder and the roll.

Furthermore, advantageously, a distance between the runnability component and the second cylinder can correspond to the moving distance of the runnability component and to the distance between the cylinder and the roll, that is, the minimum distance of the gap.

Furthermore, advantageously, the extension portion is designed such that a flow velocity in a foremost suction opening is about 30m/s to 45m/s. This enables an even negative pressure distribution in the cross machine direction .

As a material for the seals advantageously Teflon can be used. Furthermore, the material for portions and components located close to moving surfaces of the fabric, the cylinders or rolls advantageously can be also made of Teflon. The material used for the extension portion advantageously can be at least partly of transparent material .

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 are described on the basis of the attached figures, in which:

Fig. 1 shows a schematic cross sectional view of a runnability component installed in a paper or board machine known by the applicant;

Fig. 2 shows a schematic cross sectional view of a runnability component according to a first embodiment of the invention; Fig. 3 shows a schematic cross sectional view of a runnability component according to a second embodiment of the invention; and

Fig. 4 shows a schematic cross sectional view of a detail of a runnability component according to a third embodiment of the invention.

Fig. 2 shows a schematic cross sectional view of a runnability component according to a first embodiment of the invention. The runnability component comprises a main portion 1 having a circular cross section. An extension portion 3 is attached to the main portion 1 and extends into a gap formed between a cylinder 121 and a roll 123. A web W is guided about the cylinder 121 to be transferred to the roll 123 in the gap. The web W is supported by a fabric which is also guided about the cylinder 121 and the roll 123. Thereafter, the web as well as the fabric is transferred from the roll to a second cylinder 125. Thus, when being guided about any of the cylinders, the web is arranged between the surface of the cylinder and the fabric .

To ensure the web run from the cylinder 121 to the roll 123, in the gap a negative pressure is generated.

Therefore, the air in the gap is sucked via the extension portion 3 and holes 2 provided between the extension portion 3 and the main portion 1, into the main portion 1, from where it is transferred to the environment.

For sealing the gap, in which the negative pressure is generated, double seals 5 and 7 are provided at an end of the extension portion 3. The seal 5 is in abutment against the surface of the roll 123 and the seal 7 is in abutment against the fabric supporting the web and guided about the cylinder 121. Thus, the negative pressure in the space of the gap between the fabric supporting the web W and the roll 123 is reliably ensured.

The main portion 1 of the runnability component is supported on a support 17 via two arms 20. The arms 20 are connected with the support 17 via a pivot point 19. Thus, a rotation of the arms 20 and the whole runnability component about the pivot points 19 is possible.

Furthermore, the support is connected to a machine frame via a vertical mover 13 and a horizontal mover 11. By actuating the horizontal mover 11 and the vertical mover 13, a move of the main portion 1 and the attached extension portion 3 in the shape of an arc is achieved about the pivot points 19. Thereby, the seals 5 and 7 are moved away from the surface of the roll 123 and the fabric guided about the cylinder 121, respectively.

Thus, it is possible to replace the fabric, the seal 5 or 7, respectively. In Fig. 2 the runnability component is shown in an operating position, that is, the extension portion 3 extends into the gap and the seals 5 and 7 are in abutment against the surface of the roll 123 and of the fabric supporting the web , respectively.

Additionally, the embodiment shown in Fig. 2 can be modified by the components shown in dotted lines as an alternative modification of the first embodiment. According to the modified embodiment, a guide plate 23 for guiding the movement of the main portion 1 is provided. The guide plate is connected to a machine frame via a second vertical mover 15. In the guide plate 23, guide holes 25 are provided. These guide holes serve for guiding journals 21, which are provided at the ends of the runnability component .

Thus, by moving the second vertical mover 15 or the vertical mover 13 and the horizontal mover 11, the movement of the main portion 1 and the attached extension portion 3 can be reliably aligned for the operating position, in which the seals 5 and 7 are in abutment against the fabric and the surface of the roll 123, respectively. In the operation position the runnability component is locked. For maintenance purpose, the runnability component can then be moved from the operation position by using long holes shown in dotted lines, hinges 19, etc., to move the extension portion 3 and the seals 5 and 7.

In the operating position of the runnability component, the distance between the main portion 1 and an adjacent cylinder 125 corresponds to the distance of the gap, that is, the distance between the first cylinder 121 and the roll 123, plus the movement distance. The movement distance of the runnability component is at least the distance of the gap. Thus, the distance between the main portion and the cylinder 125 is at least twice the distance of the gap between the first cylinder 121 and the roll 123.

Fig. 3 shows a schematic cross sectional view of a runnability component according to a second embodiment of the invention. In the description of the second embodiment, components corresponding to those of the first embodiment are marked with the same reference signs and their description will be omitted.

The runnability component according to the second embodiment has a main portion 51 with a polygonal cross section. An extension portion 53 of the main portion 51 extends into a gap formed between a cylinder 121 and a roll 123. The extension portion 53 is provided with a suction portion 59 and an end piece 61 extending from there into the gap. A seal 55 being in abutment against the surface of the roll 123 and a seal 57 being in abutment against a fabric guided about the surface of the cylinder 121 and supporting a web W are provided at a connection from the extension portion 53 to the suction/blowing portion 59. The seals 55, 57 seal the gap between the fabric and the roll 123 against the environment.

The main portion 51 is supported on a support plate 17 via one pivotally supported arm 20 and one gliding arm 63. The arm 20 has a pivot point 19 connected with the support plate 17 and on its other end a retainer supporting a journal 21. The journal 21 is attached to the main portion 51.

In the area of the gliding arm 63, the support plate 17 is provided with a gliding plate 65. The gliding plate 65 is mounted in an oblique manner such that the end closer to the gap is arranged lower than its end located more distant from the gap. The gliding arm 63 is capable to glide over the gliding plate 65 by means of two rolls 67 and 68 which are located above and below of the gliding plate 65.

The support plate 17 is connected with a machine frame via a vertical mover 13 and a horizontal mover 11. In addition to the vertical and the horizontal movement by the vertical mover 13 and the horizontal mover 11, a lever 22 is provided. By moving the lever 22 in the direction shown by an arrow A in Fig. 3, the main portion 51 can be pivoted about the journal 21 into the position shown by dotted lines in Fig. 3, that is into a maintenance position. When the lever 22 is actuated, the runnability component is moved. While the arm 20 is rotated about the pivot point 19, the gliding arm 63 glides along the gliding plate 65 by means of the two rolls 67 and 68.

In Fig. 3 the maintenance position achieved by the main portion and the journals 21, 27, respectively, is shown by dotted lines. In this position, the seals are sufficiently moved away from the surface of the roll 123 and the fabric. Thus, a sufficient working space for replacing the seals 55, 57 or the fabric is enabled. Furthermore, by moving the runnability component along an arc, as is the case in this embodiment, both extreme positions, that is, the operating position as well as the maintenance position can be maintained because of the own weight of the runnability component. Therefore, an accidental movement of the runnability component while replacing the seals 55, 57 or the fabric can be avoided.

Fig. 4 shows a schematic cross sectional view of a runnability component according a third embodiment to the invention. Especially, from Fig. 4 the extension portion and the gap between a cylinder 121 and a roll 123 can be taken .

The main portion 71 of the runnability component according to the embodiment has a polygonal cross section. The extension portion 73 has a rectangular cross section which is opened towards the gap. Thus, the extension portion 73 has the shape of a channel arranged in the cross machine direction. In the channel of the extension portion 73, a seal holder 81 is inserted. The seal holder has a

rectangular cross section fitting to that of the extension portion 73 and is opened towards the gap. At its ends, the seal holder 81 is provided with a seal 75 being in abutment with the surface of the roll 123, and a seal 77, being in abutment with the fabric guided about the cylinder 121. In the short side of the seal holder 81, being opposed to the open side, holes 82 are provided to enable an air flow to the main portion 71. Correspondingly, a hole 74 is provided in the bottom of the channel forming the extension portion 73. In Fig. 4 the air flow is shown by dotted arrows.

In the main portion 71 a journal 83 is provided, which has an arm connected with a joint 85. Furthermore, the joint 85 is provided at the end of a mover 87 being connected to the seal holder 81 in the area of the hole 82. The air flow passes through the chamber 89, because the mover 87 is merely provided on the end portion of the runnability component .

For moving the seals away from the surface of the roll 123 and the fabric guided about the cylinder 121, respectively, the arm 86 is rotated about the journal 83. Thereby, the joint 85 is moved in a direction of the axis of the extension portion 73 and the seal holder 81. Thus, by rotating the arm 86, the seals 75 and 77 can be

sufficiently moved away in order to replace them or to replace the fabric.

Furthermore, all runnability components described above are provided with end covers 9, 79 for sealing the gap in cross machine direction at the respective ends of the cylinder 121 and the roll 123. These end covers 9, 79 can be made at least partly of transparent materials to enable an in situ inspection while the paper or board machine is in operation .

It is noted that components of the above described embodiments can be combined and exchanged with those of other embodiments. For example it is possible to employ the extension portion 73 of Fig. 4 with the runnability component of Fig. 2 instead of its extension portion 3.

Furthermore, in the first embodiment of Fig. 2, it is possible to omit the arms such that merely a combined linear movement takes place. Alternatively, a mere rotational movement can be carried out by omitting the vertical and horizontal movers.

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