WO2011086231A1

WO2011086231A1 - Device for a web forming section of a fiber web machine

Info

Publication number: WO2011086231A1
Application number: PCT/FI2011/050003
Authority: WO
Inventors: Tuomo Juvakka; Tero PÄRSSINEN
Original assignee: Metso Paper, Inc.
Priority date: 2010-01-15
Filing date: 2011-01-05
Publication date: 2011-07-21
Also published as: EP2524083A1; FI20105026A; EP2524083A4; FI20105026A0; CN102713056A

Abstract

The invention relates to a device (10) for a web forming section of a fiber web machine, the device being a deckle liner (12) adaptable to a fabric (14) of a web forming section (11) for supporting the stock layer, and the deckle liner (12) including water supply means (18) arranged on the fabric (14) side (15), i.e., on the bottom surface (15) of the deckle liner (12), for supplying water between the deckle liner (12) and the fabric (14). At least part of the water supply means (18) is adapted to be followed by a substantially planar sliding surface (38) in the travel direction (60) of the fabric (14).

Description

DEVICE FOR A WEB FORMING SECTION OF A FIBER WEB MACHINE

The invention relates to a device for a web forming section of a fiber web machine, the device being a deckle liner adaptable to a fabric of a web forming section for supporting the stock layer, and the deckle liner including water supply means arranged on the fabric side, i.e., on the bottom surface of the deckle liner, for supplying water between the deckle liner and the fabric.

Deckle boards are used in a web forming section of a web forming machine for supporting the stock layer supplied to the web forming section and for preventing its spreading outside the fabric. In prior art deckle boards, a water jet is used to define the spreading of stock. Prior art is represented by the European patent publication FIEP 1740766 registered in Finland wherein one such deckle liner operating by means of a water jet is proposed. In this deckle liner, water is sprayed between the fabric and the deckle liner as well as between the deckle liner and the stock layer. This device is fixedly supported to the constructions of the web forming section. Lamellas are installed on the bottom surface of the deckle liner to improve the sealing of the gap between the fabric and the deckle liner. A problem with the above technique is that when supplying water both to the side of the deckle liner and below it, the water consumption becomes substantial. The lamellas on the bottom surface of the deckle liner are exposed to contacts with the fabric and become easily worn while simultaneously wearing the fabric. Furthermore, a fixed fastening to the web forming section complicates the use of an adjustable headbox of a web forming section in connection with such a deckle liner.

The object of the invention is to provide a device for a web forming section of a fiber web machine which device eliminates at least part of the above mentioned problems. This object can be achieved according to the invention by- adapting at least part of the water supply means arranged on the bottom surface of the deckle liner to be followed by a substantially planar sliding surface in the travel direction of the fabric. The bottom surface of the deckle liner, i.e., the fabric side of the deckle liner, includes at least one water supply area. According to an embodiment, the water supply area may include at least one recess for distributing water uniformly between the bottom surface of the deckle liner and the fabric, as well as water supply means for supplying water or a similar medium to the recess . The water supply area is followed by at least one sliding plane area in the travel direction of the fabric, on the bottom surface of the deckle liner. The sliding plane area is mainly planar sliding surface and it is adapted to create at the deckle liner, together with water coming from the water supply area, buoyancy which is as high as the weight of the deckle liner. In the water supply area, the water supplied spreads, due to pressure and the fabric movement, to the sliding plane area at the deckle liner bottom and is conveyed along with the moving fabric below the planar sliding plane area to form a water film on which the deckle liner "slides". The surface of the at least one recess on the bottom surface of the deckle liner may form a "ski tip", which facilitates maintaining the deckle liner on the water film. The pressure of the water supplied compensates for the pressure generated by the mass of the deckle liner. Water supplied in the water supply area serves as sealing water keeping the fiber stock away from below the deckle liner while the deckle liner simultaneously supports the stock layer by its flank.

Fastening of the device according to the invention is implemented in such a way that it facilitates the positioning of the device so that the gap between the deckle liner and the fabric becomes sealed with water and prevents lateral spreading of the stock layer on the fabric. The fastening of the deckle liner and its "sliding" on the water film prevent the contact between the fabric and the deckle liner, which remarkably reduces the wear of the fabric and the deckle liner.

According to an embodiment, one end of the device is connected to the end plate of a headbox of a web forming machine by means of double pivoting. In double pivoting, one pivot is connected to the headbox end plate, the other one is connected to the deckle liner, and the pivots are linked with a linking element. With double pivoting, it is possible to use an angle-adjustable headbox in which the tilt angle can be adjusted. When moving an angle-adjustable headbox, the deckle liner moves only in the travel direction of the fabric or against it such that its position relative to the fabric remains the same at all times and it is not necessary to remove it while performing position adjustments for the headbox.

Sealing of the deckle liner is performed only in the gap between the deckle liner and the fabric, which reduces the water consumption compared to devices according to prior art. Due to the fabric movement speed and the deckle liner, the sealing water barely penetrates the fabric but continues as a wake current on the fabric even after passing by the deckle liner. This is partly influenced by the amount of water which remains relatively small.

A device according to the invention for a web forming section of fiber web machine is advantageously suitable for use in paper and board machines but also in other similar applications , such as in pulp and tissue machines .

The invention is described below in detail by making reference to the enclosed drawings which illustrate some of the embodiments of the invention, in which Figure 1 is an axonometric view of an embodiment of a deckle liner seen from the direction of its set- ting against the fabric,

Figure 2 I s an axonometric, lateral view of the deckle liner of Figure 1 ,

Figure 3 is a top view of one embodiment for fastening a deckle liner in a web forming section,

Figure 4 is a lateral view of the device of Figure 3, Figure 5 is a cross-sectional, lateral view of the deckle liner of Figure 2.

Figure 1 is an axonometric view of a device according to the invention for a web forming section of a fiber web machine. The device 10 is a deckle liner 12 adaptable to a fabric of a web forming section, one purpose of the device being to support the stock layer 36 (Figure 3). The deckle liner 12 includes water supply means 18 arranged on the fabric side 15, i.e., on the bottom surface 15 of the deckle liner 12, for supplying water between the deckle liner 12 and the fabric. At least part of the water supply means 18 is adapted to be followed by a substantially planar sliding surface 38 in the travel direction 60 of the fabric 14 (Figures 3, 4 and 5) . The fabric side 15 of the deckle liner 12 is practically the bottom surface 15 of the deckle liner 12. Figure 1 also depicts a groove 27, according to an embodiment, made on the bottom surface 15 of the deckle liner 12, which groove is not mandatory in the implementation of all embodiments.

The deckle liner is made, for example, of plastic or a similar material suitable for the application, such as a composite material or even steel. For example, the deckle liner 12 is machined or cast to form a rectangular beam which includes water supply means 18. These water supply means 18 include at least one water supply area 22 comprising, according to one embodiment, at least one recess 20 for distributing water uniformly between the deckle liner 12 and the fabric. In addi- tion, connection means 21 (Figure 2) are adapted to the deckle liner 12 for supplying water to the recess 20. The recess 20 may have one or more water supply points 39 with which water is discharged to the recess 20.

The recesses 20 are so designed that water supplied to these by means of the water supply points 39 included in the connection means 21 is uniformly distributed to the bottom 15 of the deckle liner 12 to form a uniform and relatively thin water film. In this connection, the term uniform refers to that water is distributed to the main part of the width of the bottom surface 15 of the deckle liner 12. In this case, the water supply means 18 include a recess 20 and water supply points 39 adapted thereto from which sealing water is supplied to the recess 20. The water of the water supply points 39 comes along the connection means 21 through the deckle liner 12 as shown in Figures 1 and 5.

The connection means include, for example, sleeves 34 connected to the upper surface 23 of the deckle liner and bores 33 (Figure 5) located inside the deckle liner 12, which extend to the water supply points 39 in the recesses 20. The water supply points may be oriented according to the travel direction of the fabric but also perpendicularly to the fabric, inclined rela- tive to the travel direction of the fabric, or even opposite to the travel direction of the fabric. The number of the water supply points can vary from one to several depending, for example, on the amount of water supplied and the volume of the recess .

According to an embodiment, the recesses can have a width ranging from 50 to 95% of the width of the deckle liner, a depth in the range of 0.1 cm to 4.0 cm, and a length in the range of 1.0 to 9.0 in the longitudinal extension of the deckle liner. Advantageously, the recess 20 is so designed that the depth of the recess 20 reduces in the travel direction 60 of the fabric 14 and has advantageously a key-like shape.

According to another embodiment, the water supply points can also be connected as a water supply incision.

According to still another embodiment, the water supply means 18 can include water supply points 39 without a recess adapted to that surface of the deckle liner 12 which sets against the fabric 14. Like the recess, the water supply points can be in an arrangement along the width direction of the deckle liner 12 or even inclined relative to the longitudinal direction of the deckle liner 12. A mixed design including both recesses and points is of course also possible.

As shown in Figure 1, the surfaces of the recesses 20 can be oriented in an angle relative to the plane of the bottom surface 15 of the deckle liner 12, this angle functioning as a kind of a "ski tip" for the water flowing below the bottom surface 15 of the deckle liner 12, i.e., water coming from a previous recess 20 in the travel direction of the fabric 14 creates a pressure against the following recess 20, which pressure serves as a lifting force for the deckle liner 12. The surfaces of the deckle liner 12 are mainly smooth and non-porous .

The deckle liner can have a length in the range of 0.5 to 7 meters, for example. The deckle liner can extend almost from the headbox almost to the dry limit. The height and thickness of the deckle liner are determined according to the application.

For achieving sufficient sealing, water supply areas are adapted to the deckle liner at predetermined intervals. The total number of the water supply areas can be determined according to the total length of the deckle liner. According to an embodiment, water supply areas can be at intervals of 10 to 50 cm on the bottom surface of the deckle liner. The mutual distance between the water supply areas can vary according to the weight, length and width of the deckle liner as well as the amount of water supplied, and the distance can be separately defined according to the application.

In addition to the water supply area 22, the deckle liner 12 includes at least one sliding plane area 24 which is mainly planar sliding surface 38. The sliding plane area 24 is adapted to form at the deckle liner 12 , together with water coming from the water supply area 22, buoyancy which is as high as the weight of the deckle liner 12. The movement of the fabric creates a water film between the deckle liner and the fabric. Then the water film lifts the deckle liner 12 to a "slide", i.e., the deckle liner 12 is on the water film without contacting the fabric 14. The portion of the surface area of the sliding plane area 24 from the total area of the bottom surface 15 of the deckle liner 12 ranges from 50 to 95%. The planar sliding plane area 24 does not wear either the fabric 14 or the deckle liner 12. Moreover, with the planar sliding plane area 24, the thickness of the water film remains very thin, whereby the amount of water required remains small. In addition, a small amount of water does not affect the edge area of the formed stock layer, which may have influence on the quality of the final product produced from the edge area.

A device according to the invention is advantageously connected with vertical pins at its ends, which vertical pins enable the vertical movement of the deckle liner but prevent the deckle liner from moving in the transverse direction relative to the travel direction of the fabric.

Figure 3 shows one possibility of fastening the deckle liner 12 to the headbox 28. This fastening according to the embodiment is based on double pivoting which is surprising for one part, enabling the use of the deckle liner 12 also in adjustable headboxes. On the other hand, an arrangement 30 is adapted to that side 23 of the deckle liner 12 according to this embodiment which is opposite to the side 15 setting against the fabric 14, for fastening the deckle liner 12 to the web forming section 11, which arrangement 30 is adapted to eliminate the transverse movement of the deckle liner 12 and to allow the vertical movement of the deckle liner 12. For example, the arrangement 30 can consist of pins which allow the vertical movement of the deckle liner 12 with the movement of the fabric 14 but keep the deckle liner 12 in place in the transverse direction. Thus the arrangement 30 enables for the deckle liner 12 to "float" on the water film during the operation. When an angle-adjustable headbox is used in the web forming section, fastening of the deckle liner to the headbox in a functional way creates problems . When changing the tilt angle of the headbox via the pivot point 50, the position of the slice opening moves in the vertical direction as well as in the machine direction. Therefore, the deckle liner 12 includes double pivoting 26 which allows the machine directional movement of the deckle liner 12 for adapting the deckle liner 12 to an adjustable headbox 28 of a fiber web machine. According to an embodiment, double pivoting 26 can be implemented with one pivot point 42 connected to the headbox 28, one pivot point 44 connected to the deckle liner 12 and a linking element 40 that links the pivot points 42 and 44. The deckle liner 12 is double-pivoted to the end plate 46 of the headbox 28. For the pivot point 44, the end plate 46 of the headbox 28 can be provided, for example, with a fastening beam 48 having a width equal to that of the deckle liner 12.

Figure 4 shows a lateral view of a floating double pivot assembly 26. When changing the position of an adjustable headbox 28, the position of the pivot 42 changes. The change may take place in the vertical direction but also in the travel direction of the fabric 14 or against it. As the pivot 42 moves, the linking element 40 also moves the pivot 44 which is fastened to the deckle liner 12. Due to the double pivoting 26, the pivot 44 moves only in the travel direction of the fabric 14 or against it, i.e., only in the longitudinal direction of the deckle liner. The deckle liner 12 is always kept in the correct position relative to the fabric regardless of the movement. This allows making adjustments for an adjustable headbox 28 without removing the deckle liner 12 from the headbox.

According to an embodiment of the device according to the invention, sealing of the gap between the deckle liner 12 and the fabric 14 can be improved with an arrangement in which at least one water supply area 22 is adapted to be followed by a groove 27 in the longitudinal direction of the deckle liner 12, as shown in Figure 1. The groove 27 is filled with water coming from the water supply area 22 and seals the gap further. The width of the groove is narrow relative to the width of the bottom surface 15 of the deckle liner 12 such that the main part of the bottom surface 15 is still planar sliding surface 38. According to an embodiment, the groove is located on the bottom surface of the deckle liner, on the stock layer side of the bottom surface, such that the bottom surface of the deckle liner located in the edge side part of the fabric is planar sliding surface.

According to still another embodiment, the water supply means 18 can include discrete water supply points 39 without a recess adapted to that surface of the deckle liner 12 which sets against the fabric 14. Like the recess, the water supply points can be in an arrangement along the width direction of the deckle liner 12 or even inclined relative to the longitudinal direction of the deckle liner 12.

Claims

1. A device (10) for a web forming section of a fiber web machine, the device being a deckle liner (12) adaptable to a fabric (14) of a web forming section (11) for supporting the stock layer (36), and the deckle liner (12) including water supply means (18) arranged on the fabric (14) side (15), i.e., on the bottom surface (15) of the deckle liner (12), for supplying water between the deckle liner (12) and the fabric (14), characterized in that at least part of the water supply means (18) is adapted to be followed by a substantially planar sliding surface (38) in the travel direction (60) of the fabric (14) .

2. A device according to claim 1, characterized in that the water supply means (18) include at least one water supply area (22) comprising at least one recess (20) for distributing water uniformly between the deckle liner (12) and the fabric (14) , and connection means (21) adapted to the deckle liner for supplying water to said recess (20) .

3. A device according to claim 2 , characterized in that said water supply area (22) includes one or more water supply points (39 ) .

4. A device according to any of claims 1 - 3 , characterized in that the deckle liner (12) includes at least one sliding plane area (24) adapted to the fabric (14) side (15) of which area the main part is planar sliding surface (38) and which is adapted to create at the deckle liner (12), together with water coming from the water supply area (22), buoyancy which is as high as the weight of the deckle liner (12).

5. A device according to any of claims 1 - 4, character- ized in that the portion of the area of the sliding surface (38) relative to that side (15) of the deckle liner (12) which sets against the fabric (14) is between 50 and 95%.

6. A device according to any of claims 1 - 5, character- ized in that an arrangement (30) is adapted to the side (23) of the deckle liner (12) opposite to the side (15) that sets against the fabric (14) for fastening the deckle liner (12) to the web forming section (11) , which arrangement (30) is adapted to eliminate the transverse movement of the deckle liner (12) and to allow the vertical movement of the deckle liner (12) .

7. A device according to any of claims 1 - 6, characterized in that the deckle liner (12) includes double pivoting (26) that allows the machine directional movement of the deckle liner (12), for adapting the deckle liner (12) to an adjustable headbox (28) of a fiber web machine.

8. A device according to claim 7 , characterized in that said double pivoting (26) includes one pivot point (42) con- nected to the headbox (28), one pivot point (44) connected to the deckle liner (12), and a linking element (40) that links the pivot points (42, 44).

9. A device according to any of claims 2 - 8 , character- ized in that the water supply area (22) is adapted to be followed by a groove (27) .