CURTAIN APPLICATION DEVICE

Abstract

 The invention relates to a curtain application device (10) for fiber machines, in particular for paper and board machines comprising an application beam (13), which comprises at least one treatment substance chamber (14) with a nozzle opening (14A), a frame structure (11), support arms (12) attached at one end to the frame structure (11) and at the other end to the application beam (13), edge guides (20). Each of the edge guides (20) is movable in vertical direction such that vertical location (H20) of the edge guide (20) is adjustable independently from vertical location (H) of the application beam (13).

Description

[0001] The invention relates to a curtain application device for fiber machines, in particular for paper and board machines. More especially the invention relates to a curtain application device in accordance with features of the preamble part of claim 1.

[0002] For example surface treated, such as coated or sized fiber web grades are becoming more and more popular and thus the process and equipment have increasing demands imposed thereon. In application the surface of a fiber web is formed with a layer of treatment substance at an application station followed by drying. The process of application can be divided in supplying the treatment substance onto the web surface, which is called the application of the treatment substance, as well as in the adjustment of final amount of treatment substance. One important recently developed application technique is curtain application, which is suitable to surface treatment of paper and board webs. By curtain application good coverage of treatment substance on the web surface is achieved.

[0003] In curtain application two main types of curtain application devices are used, namely curtain application devices with slot-fed and curtain application devices with slide-fed. In the slide fed curtain application devices, treatment substance is fed by means of a nozzle assembly onto an inclined plane and the treatment substance flows down towards an edge of the plane constituting a nozzle lip and the curtain is formed as the treatment substance falls off the nozzle lip onto the web. In the slot-fed curtain application devices treatment substance is pumped through a distribution chamber into a narrow vertical slot and the curtain is formed at its lip and falls onto the web. Treatment substance can be applied in one or more curtain layers.

[0004] Typically two different methods are used to control width of the curtain. One is to feed the curtain wider than width of the fiber web and then the width is allowed freely narrow in cross direction of the web as the curtain falls downwards towards the application surface. This method is called as out-board method. The other, called as in-board method, is to feed the curtain narrower than the width of the fiber web, and the width is required to maintain uniform as the curtain falls downwards towards the application surface. The curtain is maintained at required width by means of edge guides which are located along each edge of the feeding slot / the nozzle lip. The present invention relates to both out-board curtain application and in-board curtain application. The present invention also relates to direct curtain application, in which the treatment substance is applied directly onto the fiber web, and to in-direct curtain application, in which the treatment substance is applied via a roll or corresponding transfer surface onto the fiber web.

[0005] In curtain application edge guides are used to prevent reducing of the width of the curtain in vertical direction towards the application surface as in curtain application it is important that the width of the curtain stays required with the height of the curtain so that full-width treatment substance application is achieved.

[0006] The edge guides typically used in curtain application have a fixed length in direction of the curtain and thus are limited between the nozzle opening and the application surface and therefore extend on the same height level as the height of the curtain. Thus in cases the application process should require adjustment of the height of the curtain it is not possible to adjust the edge guides such that required effect to the process would be achieved. The height position adjustment of the edge guides is needed for example in cases where the running speed of the fiber web varies or in cases where the amount of the treatment substance to be applied by the nozzle varies so that the curtain keeps its stability.

[0007] It is known from prior art to have means in curtain application to adjust the height or the width of the curtain during running of the fiber web and during application of the treatment substance but not simultaneously. In US patent publication 3508947 is disclosed a method for simultaneously applying a plurality of coated layer by forming a stable multilayer free-falling vertical curtain, in which screw fastened edge guides are used. In US patent publication 3968772 a curtain-coating apparatus with laterally adjustable edge guides is disclosed. In US patent publication 5330797 is disclosed a curtain coater with displaceable edge guides.

[0008] An object of the invention is to create a curtain application device in which the disadvantages of the prior art, especially relating to adjustment of the width and the height of the curtain in curtain application, are eliminated or at least minimized.

[0009] In order to achieve the above objects and those that will come apparent later the curtain application device according to the invention is characterized by the features of the characterizing part of claim 1. Advantageous embodiments and features are defined in dependent claims.

[0010] According to the invention the curtain application device for fiber machines, in particular for paper and board machines comprises an application beam, which comprises at least one treatment substance chamber with a nozzle opening, a frame structure, support arms attached at one end to the frame structure and at the other end to the application beam, edge guides each of which is movable in vertical direction such that vertical location of the edge guide is adjustable independently from vertical location of the application beam.

[0011] According to an advantageous feature of the invention each of the edge guides is movably in vertical direction attached to a frame part, which is attached to the frame structure of the application device.

[0012] According to an advantageous feature of the invention height of treatment substance curtain created by the application device is adjusted by moving the application beam and the vertical location of the edge guides is adjusted independently from the vertical location of the application beam during running of the fiber web and during the application of the treatment substance.

[0013] According to an advantageous feature of the invention length of the edge guides is greater than the distance between the nozzle opening and the surface onto which the treatment substance is first applied and that the edge guides extend through corresponding openings in the frame part.

[0014] According to an advantageous feature of the invention the frame parts of the edge guides are in width direction adjustably attached to the frame structure of the application device, such that the location of the edge guide is adjustable during running of the fiber web and during application of the treatment substance.

[0015] According to an advantageous feature of the invention each of the edge guides are connected to an actuator by which the adjustment of the vertical position of the edge guide is achieved. The actuator is advantageously a cylinder attached to the upper end of the edge guide at one end and at the other end to a frame part of the application device, for example to the support beam of the application beam. The actuator may also be attached to the application beam of the application device but in this case it is connected by mechanical transmission or by adjustment means with electrical measurement means to the height (vertical location) control of the application beam such that the change of the vertical location of the application beam is taken in account with the vertical location adjustment of the edge guides.

[0016] According to an advantageous feature of the invention the vertical location adjustable edge guides provide the possibility of placing a deflection (start) plate, which is typically a movable plate under the curtain for at least collecting the treatment substance before and/or after the application of the treatment substance onto the application surface, under the application beam such that in the start of the application the edge guides are quickly lowered down to their working position, near the surface of the fiber web in direct application or the surface of the roll in in-direct application. By this the time possibly causing application defects at the edge areas (typically a heavy edge due to the reduction of the width of the curtain) is minimized.

[0017] According to an advantageous feature of the invention the edge guides are located and stay in vertical position in respect of the direction of the movement of the fiber web, by which the adherence of the edges of the curtain to the edge guides is ensured as the edge guides are not turned in the direction of the movement of the fiber web as is needed in prior art arrangements.

[0018] According to an advantageous feature of the invention each of the frame parts supporting the edge guides are connected to an actuator by which the adjustment of the width position of the edge guide is achieved.

[0019] According to an advantageous feature of the invention the edge guides are attached in-flow connection with the treatment substance chamber of the application device such that advantageous additional feed of the treatment substance can be provided to follow the edge guides.

[0020] According to an advantageous feature of the invention the curtain application device is typically located in a finishing section of a fiber web production line, advantageously in a sizing section or in a coating section but the curtain application device can also be located in another section of a fiber web production line, for example in a wire section or in a press section or in a drying section or in a calendering section of a fiber web production line. For example the curtain application device can be used for application of a sizing or coating agent in dry end of a fiber web production line or for fiber web sizing in the wire section or the press section.

[0021] The invention can be utilized both in cases where the treatment substance is directly applied onto the surface of the fiber web and in cases where the treatment substance is first applied onto a surface of a roll via which the treatment substance is guided onto the surface of the fiber web. Especially in cases where the treatment substance is first applied onto the surface of the roll a small distance between the closest end of the edge guide and the surface of the roll is needed. According to an advantageous feature of the invention the distance between the closest end of the edge guide and the surface of the application surface or the roll is over 0 mm and less than 10 mm, advantageously less than 3 mm, so that the curtain is guided substantially its whole height by the edge guides.

[0022] The invention is advantageously utilized in connection with a nip formed between two rolls, in which in connection with both rolls the application device can be arranged and by both the treatment substance is applied indirectly via the corresponding roll and the nip onto the fiber web or in connection with one indirect application is used and by the other application device the treatment substance is applied directly onto the fiber web. The nip may be formed between a hard roll and a soft roll or between two hard rolls or between two soft rolls. The hard roll is a roll provided with hard surface, typically with ceramic or metallic surface (a roll with a ceramic or carbide coating having surface hardness 800 - 1600 HV0.3) and the soft roll is a roll provided with soft surface, typically formed by a polymer cover (a roll with a polymeric roll cover (rubber or polyurethane) having surface hardness 10 - 70 P&J, roll with a polymeric roll cover (rubber, polyurethane or composite) having surface hardness 80 - 100 shoreD.

[0023] According to an advantageous feature of the invention the edge guides are in vertical direction in respect of the main place of the surface onto which the treatment substance is to be applied substantially vertically positioned as by this feature the best process adjustment in respect of height of the curtain is achieved.

[0024] Advantageously the vertical position of the edge guides may be inclined towards the curtain, the inclination angle being 0-15°, advantageously 1-7°.

[0025] According to an advantageous aspect of the invention the edge guides are attached to the application beam movably in vertical direction. The length of the edge guides is greater than the distance between the nozzle opening and the application surface and the edge guides extend through corresponding openings in the frame part such that height of the curtain can be adjusted by moving the application beam and the vertical location of the edge guides can be adjusted independently from the vertical location of the application beam during running of the fiber web and during the application of the treatment substance. According to an advantageous feature of the invention a vertically extending groove is on the edge guide located at the side of the curtain such that treatment substance flow increased and additional treatment substance can be guided along the groove and thus secure that the edges of the curtain will follow along the corresponding edge guides. The groove of the edge guide extends from the free end of the edge guide i.e. the closest end of the edge guide in respect the surface onto which the treatment substance is applied to the treatment substance chamber of the application device.

[0026] According to an advantageous aspect of the invention the edge guides are attached to corresponding frame parts of the application device, which frame parts are fixedly attached or in width direction adjustably attached to the application device. Advantageously the location of each edge guide in width direction is independently from the other edge guide adjustable. The edge guides are attached to the frame parts such that the position of the edge guide is adjustable in vertical direction such that the edge guide can be lifted or lowered during running of the fiber web and during running of the application of the treatment substance. Advantageously the edge guides are connected via the in width direction adjustable frame parts to the control structures of the width of the curtain.

[0027] By the invention many advantages are achieved. The invention provides for from the curtain height adjustment independent adjustment of the vertical location of the edge guides. The invention provides for adjustment of both width and height of the curtain in curtain application simultaneously during running of the fiber web and during application of the treatment substance. The invention is very advantageous in cases where the treatment substance to be applied is size and the size is first applied onto a surface of a roll and via the surface of the roll onto the surface of the fiber web as in these cases it is very important that the width of the curtain remains full width along its substantially whole height. Also by the invention is achieved easily adjustable location in vertical direction in respect of the surface of the fiber web or the roll independent from the vertical position of the application beam.

[0028] In this description and claims by term width of the curtain is meant the dimension of the curtain in width direction of the application surface i.e. in perpendicular direction to the main running direction of the fiber web. The application surface is in direct curtain application the surface of the fiber web and in indirect application the surface of the roll or corresponding transfer surface, via which the treatment substance is guided onto the fiber web. By term height of the curtain is meant the distance between the nozzle opening and the application surface (= free falling curtain by the gravity). The upper and lower are used in respect of the flow direction of the curtain; upper being in direction of the beginning of the curtain and lower in direction of the end of the curtain. The vertical direction is to be considered to be the perpendicular direction in view of the main plane direction of the fiber web and the main flow direction of the curtain.

[0029] In the following the invention will be explained more closely by reference to the accompanying drawing in which

In figure 1 is schematically as a side view presented one advantageous example of an edge guide of a curtain application device in accordance with the invention,

in figure 2 is schematically as a side view presented another advantageous example of an edge guide of a curtain application device in accordance with the invention,

in figure 3 is schematically as a front view presented an advantageous example of an edge guide of a curtain application device in accordance with the invention,

in figures 4A-4B is schematically as a cut view presented an advantageous example of an edge guide and

in figure 4C is schematically as a two dimensional side view presented another advantageous example of an edge guide of a curtain application device in accordance with the invention.

[0030] During the course of the following description of figures 1 - 4C like numbers and signs will be used to identify like elements, parts and part components unless otherwise mentioned. In the figures some references sign have not been repeated for clarity reasons. In the following the examples are described mainly by reference to an edge guide of a curtain application device of a fiber web in view of simplifying the disclosure but it should be noted that instead of this example any type of an edge guide of curtain application device can have similar features and properties in accordance with the invention.

[0031] In examples of figures 1, 2 and 4C only one end of the application device 10 is shown, it is to be understood that the application device 10 extends in the cross direction in respect of the main running direction R of the application surface 30 substantially over the width of the application surface 30 as shown in figure 3 and that the other end of the application device 10 is corresponding. The application surface 30 is in direct curtain application the surface of the fiber web and in indirect application the surface of the roll or corresponding transfer surface, via which the treatment substance is guided onto the fiber web.

[0032] In the example of figure 1 is shown an example of an edge guide 20 of a curtain application device 10, in which the application beam 13 is a slide beam 13, which is used for applying the treatment substance onto the surface of the application surface 30. The slide beam 13 comprises treatment substance chambers 14 from which the treatment substance is guided through the nozzle openings 14A to slide on top of the beam and over the front edge surface 13A to form a treatment substance curtain C that flows down onto the surface of the application surface 30. The slide beam 13 is attached to the frame structure 11 of the application device 10 by support arm 12. The vertical location H of the slide beam 13 in respect of the surface of the application surface 30 is adjustable and thus height of the curtain C is adjustable. Width control means of the application beam 13 are denoted by reference numeral 15. At the edge of the curtain C is located an edge guide 20, which is located against the front edge surface 13A of the application beam 13. The edge guide 20 attached at its upper end to a frame part 21 such that it is movable in vertical direction i.e. the vertical location of the edge guide 20 is independently form the application beam 13 adjustable. An actuator (not shown) can be used to adjust the vertical location of the edge guide 20. The frame part 11 is attached to width control structure 22 of the edge guide 20 for width W adjustment of the edge guide 20. The width control structure 22 can be connected to the width control means of the application beam 13. At the lower end of the edge guide 20 can be located an additional curtain guide 23 for further ensuring the stability of the edge of the curtain C at its lower part.

[0033] In the example of figure 2 is shown an example of an edge guide 20 of a curtain application device 10, in which the application beam 13 is a slot beam 13, which is used for applying the treatment substance onto the surface of the application surface 30. The slot beam 13 comprises a treatment substance chamber 14 from which the treatment substance is guided through the nozzle opening 14A to form a treatment substance curtain C that flows down onto the surface of the application surface 30. The slot beam 13 is attached to the frame structure 11 of the application device 10 by support arm 12. The vertical location H of the slot beam 13 in respect of the surface of the application surface 30 is adjustable and thus height of the curtain C is adjustable. At the edge of the curtain C is located an edge guide 20, which is located at a small distance, advantageously 0,1-0,2 mm the front edge surface 13A of the application beam 13. The edge guide 20 attached at its upper end to a frame part 21 such that it is movable in vertical direction i.e. the vertical location of the edge guide 20 is independently form the application beam 14 adjustable. An actuator (not shown) can be used to adjust the vertical location of the edge guide 20. The frame part 11 is attached to width control structure 22 of the edge guide 20 for width W adjustment of the edge guide 20. At the lower end of the edge guide 20 can be located an additional curtain guide 23 for further ensuring the stability of the edge of the curtain C at its lower part. A chute 16 is provided to collect any treatment substance flown from the nozzle opening 14A at the edge areas on the other side of the edge guide 20 in respect of the curtain C.

[0034] In the example of figure 3 is shown an example of an edge guide 20 of a curtain application device 10, to form a treatment substance curtain C that flows down onto the surface of the application surface. The edge guides 20 are attached to a frame part 21 such that it is movable in vertical direction i.e. the vertical location of the edge guide 20 is independently form the application beam 14 (figs. 1 and 2) adjustable. The edge guides 20 are in vertical direction in respect of the main place of the surface of the application surface 30 substantially vertically positioned. The edge guides 20 may be inclined towards the curtain C, the inclination angle A being 0-15°, advantageously 1-7°.

[0035] As shown in the examples of figures 4A-4B a vertically extending groove 25 can be on the edge guide 20 located at the side of the curtain C such that treatment substance flow increased and additional treatment substance via flow channel 24 of the edge guide 20 for the additional treatment substance shown in figure 4C can be guided along the groove 25 and thus secure that the edges of the curtain C will follow along the corresponding edge guide 20. The groove 25 of the edge guide 20 extends from the free end of the edge guide 20 i.e. the closest end of the edge guide 20 in respect the surface onto which the treatment substance is applied to the supply of the treatment substance of the application device 10.

[0036] As shown in the examples of the figures the edge guides 20 are attached to the application beam 13 movably in vertical direction. The length of the edge guides 20 is greater than the distance between the nozzle opening 14A and the surface of the application surface 30 and the edge guides 20 extend through corresponding openings in the frame part 21 such that height H of the curtain C can be adjusted by moving the application beam 13 and the vertical location H20 of the edge guides 20 can be adjusted independently from the vertical location H of the application beam 13 during running of the application surface 30 and during the application of the treatment substance. The edge guides 20 are attached in-flow connection with the treatment substance chamber 14 of the application device 10 such that advantageous additional feed of the treatment substance can be provided to follow the edge guides 20. The edge guides 20 are in vertical direction in respect of the main place of the surface of the application surface 30 substantially vertically positioned. The edge guides may also be inclined towards the curtain C, the inclination angle A being 0-15°, advantageously 1-7°. The edge guides 20 are attached to corresponding frame parts 21 of the application device 10, which frame parts 21 are fixedly attached (not shown) or in width direction adjustably attached to the application device (figures).

[0037] In the previous advantageous examples of the invention are described. Many modifications and alterations are possible in view of the invention.

Reference signs used in the drawing

[0038] 

10 application device

11 frame structure

12 support arm

13 application beam

13A front edge surface of the application beam

14 treatment substance chamber

14A nozzle opening

15 width control means of the application beam

16 chute

20 edge guide

21 frame part

22 width control structure of the edge guide

23 additional curtain guide

24 fluid channel

25 groove

30 application surface

A angle

C curtain

H vertical location adjustment of the application beam

H20 vertical location adjustment of the edge guide

W width adjustment of the edge guide

R running direction

Claims

1. Curtain application device (10) for fiber machines, in particular for paper and board machines comprising application beam (13), which comprises at least one treatment substance chamber (14) with a nozzle opening (14A), a frame structure (11), support arms (12) attached at one end to the frame structure (11) and at the other end to the application beam (13), edge guides (20), characterized in, that each of the edge guides (20) is movable in vertical direction such that vertical location (H20) of the edge guide (20) is adjustable independently from vertical location (H) of the application beam (13).

2. Curtain application device according to claim 1, characterized in, that height (H) of treatment substance curtain (C) created by the application device (10) is adjusted by moving the application beam (13) and the vertical location (H20) of the edge guides (20) is adjusted independently from the vertical location (H) of the application beam (13) during running of the fiber web and during the application of the treatment substance.

3. Curtain application device according to claim 1 or 2, characterized in, that each of the edge guides (20) is movably in vertical direction attached to a frame part (21), which is attached to the frame structure of the application device (10).

4. Curtain application device according to any of claims 1 - 3, characterized in, that length of the edge guides (20) is greater than the distance between the nozzle opening (14A) and the surface onto which the treatment substance is first applied and that the edge guides (20) extend through corresponding openings in the frame part (21).

5. Curtain application device according to any of claims 1 - 4, characterized in, that each of the edge guides (20) is connected to an actuator by which the adjustment of the vertical position of the edge guide (20) is provided.

6. Curtain application device according to any of claims 1 - 5, characterized in, that the edge guides (20) are attached in-flow connection with the treatment substance chamber (14) of the application device (10).

7. Curtain application device according to any of claims 1 - 6, characterized in, that the edge guides are in vertical direction in respect of the main plane of the surface (30) onto which the treatment substance is to be applied substantially vertically positioned.

8. Curtain application device according to any of claims 1 - 7, characterized in, that vertical position of the edge guides (20) is inclined towards the curtain (C) and that inclination angle (A) being 0-15°, advantageously 1-7°.

9. Curtain application device according to any of claims 1 - 8, characterized in, that a vertically extending groove is on the edge guide (20) located at the side of the curtain (C).

10. Curtain application device according to any of claims 1 - 9, characterized in, that the frame parts (21) of the edge guides (20) are in width direction adjustably attached to the frame structure (11) of the application device (10).

Drawing