FI119825B - Nozzle construction for flat-bed fiber web curtain application device beam and method for controlling the width profile of a nozzle gap in a nozzle structure in the fiber web's CD direction - Google Patents

Description

119825

BACKGROUND OF THE INVENTION The present invention relates to a nozzle structure of a nozzle structure of at least one a nozzle slot 10 in the upper region extending in the CD direction (transverse direction) of the fibrous web which opens to an inclined feed plane on the upper surface of the nozzle structure and which are secured to each other by fastening means located in their lower region.

The invention further relates to a method for adjusting the nozzle gap width profile of a nozzle structure of a plane-fed fibrous web ver-15 applicator beam in a CD direction (transverse direction) of the fibrous web, wherein the nozzle structure has at least two fastening means located in the area and having a nozzle opening which is formed between the nozzle parts, * * * 20, at the inclined feed level of the upper surface of the nozzle structure.

The use of curtain coating for paper / board web coating is increasing because it targets much less than blade / rod coating. the force on the web and thus it causes less paper web break • ♦ v .: the breakage caused by the weaving and thus better runnability. The curtain coating does not achieve the same smoothness as the blade coating, but the coverage achieved is better than that of the blade coating.

♦ · 30 Curtain coaters can be divided into slot-fed or slide-fed coatings. In the flat-feed curtain coater, the overlay 119825 is fed by means of a nozzle assembly to an inclined plane along which the coating flows toward the edge of the plane, whereby the curtain is formed as the coating drips from the edge of the plane.

5 In slit-fed appliqué beams, the coating is pumped through a distribution chamber into a narrow vertical slot, with a lip forming a curtain and dripping onto the web. The coating may be applied in one or more layers. The resulting curtain is controlled by an edge guide, which, as its name suggests, is located at the edge of the feed slot / feed lip.

10

One problem in current coating paste curtain coaters is the limited size of the paste feed channels and, in part, the resulting flow gap control problem. Controlling the transverse profile of the paste to be applied to the web to be coated is also problematic in the prior art curtain wrapper. Normally there are no ways to manage your profile.

When designing the coating beam, the shape of the feed channels is determined which can influence the overall profile. When the properties and / or the feed rate of the coating paste are changed, these have a clear effect on the transverse profile which cannot. . fix. All manufacturing inaccuracies also affect the • · · "Y 20 profile irreparably.

t * * • • • • • • • · · · · ·

In prior art level-fed nozzles, the nozzle slot is formed by machining nozzle parts such that a desired gap is formed between successive nozzle parts.

• * · 25 The nozzle gap of the curtain coating machine is typically 0.3-0.7 mm wide and is allowed to have a relative error of 0.3-1%. This means that the gap »· · must be within 1 to 7 µm of the nominal width, e.g. 0.4 mm ± 2 µm. It is essential for the width of the slot ί, „: that the matching surfaces forming the slot are planar *: **. It is difficult for the traditional engineering industry to make such precise planar pieces easily. If sufficient accuracy cannot be achieved, the nozzle must be dismantled * * · after the gap measurement and the nozzle parts re-sanded. This is a 3 119825 very risky and time consuming way. Thus, in the previous application FI 20075239, the applicant has proposed to form a nozzle slot by inserting a spacer between successive nozzle parts, the thickness of which determines the width of the nozzle slot.

5

After the assembly, the width of the nozzle slot can be measured, e.g., a contactless pole with an electronic meter. If the measurement is not within the tolerances given for the width of the gap, the nozzle assembly may be disassembled and then sanded off the removed spacer at appropriate locations to achieve the width requirements of the gap. Changes in plate thickness can easily be measured, for example, with a micrometer screw. This type of plate-based solution can reduce the working time of the actual and expensive sander and reduce the risk of minor work failure. If the grinding machine makes any mistake while machining the actual nozzle part, the piece already made will be lost in its entirety and at the same time several hundred hours of work and the raw material consumed in the part will be lost.

The object of the present invention is to provide an improved solution orally. , tin gap profiling that does not require disassembly of the assembled nozzle assembly, e.g. to remove and grind the baffle or grind the nozzle part itself and then reassemble the nozzle assembly. To achieve this goal, the nozzle solution of the invention has characterized by the fact that the nozzle structure is embedded with members having at least one nozzle part; ***: the nominal MD length of the lower part (in the direction of the fiber web) is adjustable at the desired CD direction points so that said nozzle portion: V: the upper portion moves toward or away from the adjacent nozzle portion, causing the CD • width profile of the mouth to change as desired.

a · * aaaa • aa "**: The method according to the invention is characterized in that the a · * · .. 30 method affects the lower part of the nozzle part at the desired CD direction Γ" so that the lower part of that nozzle part is MD the nominal length (of the fiber web 4 119825 in the direction of travel) is varied in profile so that the upper part of said nozzle part moves towards or away from the adjacent nozzle part, causing the CD gap width profile of the nozzle slot to change as desired.

5

In this connection, the displacement involves rotating the upper edge of the nozzle member relative to the adjacent nozzle member, whereby the upper member changes its angular position, or the entire upper member moves uniformly relative to the adjacent nozzle member, whereby the angular position of the upper member.

10

The invention will now be described in more detail with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of an embodiment of the nozzle structure 15 described in the applicant's previous application, Figures 2A-2B schematically illustrate prior art nozzle gaps with substantially constant thickness; nozzle-forming through slabs,

Figures 2C-2E illustrate some embodiments of the invention with an adjustable nozzle slot * ········································································································································ Fig. 4 is a schematic cross-sectional view of an alternative arrangement for forming a nozzle gap of a nozzle portion of an applicator bar by a spacer, and Fig. 5 is a front view of the spacer used in the arrangement of Fig. 4.

Fig. 1 is a schematic perspective view of an embodiment of a nozzle assembly with a spacer 10 as described in the applicant's previous application FI 20075239, with a single feed slot 3. The nozzle parts 2a, 2b of the nozzle structure are ground into flat pieces. The nozzle portion 2a has a machined feed chamber 4 and an equalization chamber 10, and a feeding lip 5 is formed at the leading edge of the nozzle, over which the coating material curtain 15 (not shown) extending downwardly over the surface of the fibrous web to be coated. Between the side surface 16 of the lower portion of the nozzle portion 2a and the corresponding surface portion of the nozzle portion 2b, a baffle 8 having a thickness defines the formation between the nozzle portions 2a, 2b in the region of the upper portion of the nozzle portion . nozzle slot 3 width. The spacer plate 8 is preferably a rolled metal strip.

The nozzle parts 2a, 2b and the spacer plate 8 therebetween can be assembled, for example, by means of fastening screws which are inserted through the fastening holes 9 · ·, v ·.

Fig. 2A schematically illustrates a nozzle structure 2a-2e of one of the prior art with a plurality of nozzles 25a 3a-3d made with substantially constant thickness spacers 8a-8d. With this solution, it is possible to • optimize the melt for changing nozzle fractures as the process conditions change, e.g., paste properties ···, by changing the baffle 8a-8d with a thickness profile optimized Figure 2B i '30 illustrates schematically another embodiment of nozzle slits formed by spacers 8a-8d according to the prior art wherein the mouthpiece slot 3b is formed wider than the other nozzle slots by using thicker spacers 8b.

Fig. 2C schematically illustrates one embodiment of the application bar 5 of the present invention, wherein nozzle slots 3a-3d are formed by spacers 8a-8d. The nozzle slits may be of the same width or of different sizes. In the solution of Fig. 2C, an inwardly extending CD directional slot 41a-41d is formed on the underside of each nozzle part 2a-2d provided with a feed chamber 4, which is provided with an adjusting member 10a 40a-40d for adjusting the width of the length L1-L4, and thus the width of the nozzle slot 3a-3d at the top, respectively. In the embodiment of Fig. 2C, the adjusting member is a wedge-shaped member 40a-40d whose insertion or retraction from the adjusting slot 41a-41d causes the width of the adjusting slot 15 to change accordingly and in turn causes the upper edge of the around the nozzle slot 3a-3d to change the width accordingly. Figure 2C is an exaggerated example. . a change in the width of the nozzle slots 3a-3d as a result of the control means 40a-40d. The change in the adjustment slit, and thus the width of the nozzle slit, preferably takes place in the range of about 1 µm to about 100 µm. ·:. · Cut 0.3-0.7 mm In Figure 2, the nozzle gaps and their width changes are strongly exaggerated for the sake of illustration.

Advantageously, the adjustment slot extends as a continuous slit over substantially the entire CD direction of the mouthpiece 2a-2d, but it can also be realized in several directions in the CD direction. The adjusting member is advantageously comprised of a plurality of sequentially adjusting means in the CD direction, such as individually movable wedge-shaped means 40a-40d, which can provide a relatively fine-directional adjustment of the CD slot and thus the nozzle slot profiling. 7119825 workpiece, such as, for example, an adjustable body having several heating elements in the direction of several CDs. The adjustment of the le-5's width can be accomplished, for example, by adjusting the tensioning screws between the nozzle parts or other tensioning members. provided with heating means which vary the lower edge length locally at different points in the CD direction, providing a similar change in the angular position of the nozzle part, such as that obtained with a wedge-shaped adjusting member. Fig. 2D illustrates a heating element disposed on the underside of reference numeral 51 which causes said angular change in heat effect to region 50. The heating elements may also be positioned so as to cause the bottom to warm substantially uniformly over the entire bottom so that the length of the nozzle evenly, substantially without changing the angular position of the upper portion of the nozzle portion as schematically illustrated. , in section 2E, wherein reference numeral 50 describes the heated area of the lower part of the nozzle part • * * :: V 20.

• · · • i · * · • • • »

• »I

The advantage of the solution according to the invention is the relatively simple nozzle bar * * · ··· ·: is the width profiling in the CD direction without having to disassemble the nozzle structure to sand the spacer and / or the nozzle part itself to achieve the desired profiling. The invention can be applied to adjusting the width of both nozzle slits formed by spacers and of nozzle slots machined directly into nozzle parts.

··· • ♦ * · · ♦ «*: * ·: Figure 3 illustrates a nozzle assembly arrangement as described in the applicant's prior application, wherein inlet chamber 12 is provided with inlet spacers 8 longitudinally spaced apart. 119825 through holes 18 through which the coating paste is introduced into the equalization chamber 13 and further into a nozzle slot 3 having an upper leveling chamber 10, and further through an outlet 31 to a drainage paper and cardboard web 12 to pass through the feed lip 5 below the coater. The expansion chamber 13 extends substantially over the entire length of the nozzle portion.In the illustrated embodiment, the feed hole 18 forms an angle between the supply chamber 12 and the equalization chamber 13, opening in the position shown in Figure 3 from the horizontal supply chamber 12 and vertically to the equalization chamber 13. an external bore 19a which engages a vertical portion of the feed hole 18 and which is provided with a longitudinally movable adjusting pin 19, the inner end 23 of which extends to the feed hole 18 is preferably bevelled. An adjusting nut 21 is provided at the outer end 25 of the adjusting pin 19, by means of which the adjusting pin 19 can be displaced 15 in its longitudinal direction to change the effective cross-sectional area of the feeding hole 18. In addition, the adjusting pin is provided with a adjusting plate 20, whereby by removing the adjusting plate, the basic setting of the effective cross-sectional area of the feed hole can be changed to reduce the amount of feed. The adjusting pin 19 is,. sealed in bore 19a by seals 22. • · · *. ** of each of the feed holes 18. The distance 20 in the longitudinal direction of the nozzle part is e.g. 100 - 600 mm, preferably • · ·

»· I

.v, 150 - 300 mm to achieve the desired transverse profiling by changing the effective cross sectional area of the · · ♦ feed holes. The operation of the adjusting pins is • · · »·« advantageously automated, which also enables runner profiling in the transverse direction of the object to be coated. Reference numeral 24 denotes * · · 25 mounting levels for nozzle assembly screws. The assembly screws extend between the successive bores 19a across the water space 17 provided with the necessary sealing means of wool. When the paste is fed at several points to the equalization chambers, a greater pressure is created at these feed points than between these feed points *; * 'i. With this solution, due to the method of feeding the coating material, the cross-sectional profile of the coating material is locally spiked, i.e., to the drainage layer and thus to the coating layer formed on the surface of the 9 119825 coated fibrous web.

Fig. 4 is a schematic cross-sectional view of an alternative arrangement according to another aspect of the present invention 5 for forming a nozzle gap in a nozzle portion of an applicator bar when feeding coating material from a supply chamber 4 and nozzle slot 3 through feed holes 6. Figure 5 is a front view of the baffle 9 used in the arrangement of Figure 4. In the solution of Figures 4 and 5, preferably two spacers 8, 9 are used, one spacer 8 extending in the space between the lower portions of the consecutive nozzle parts and the other spacer 9 extending into the nozzle slot 3. The spacer 9 preferably extends below the alignment chamber 10 is shaped such that the variation in the effective length of the nozzle slot 3 corresponds to the variation in the pressure in the chamber. By doing so, it is possible to compensate for the uneven paste outlet flow from the nozzle slot 3 due to pressure fluctuations. Also, deformation of the upper end of the baffle 9 can also correct for possible misalignments in the nozzle slot 3. In the baffle, the uneven flow profile due to the feed distribution can be # corrected, and it is also possible to reduce the feed distribution, i.e., positioning the feed holes 6 in the CD direction further apart. The use of the spacer 9 allows for a substantial simplification of the manufacture of the application bar, since the length of the feed slot 3 can be kept constant and the effective length of the nozzle slot is determined by an easily manufactured (and replaceable) spacer. Fig. 5 is a schematic front view of the baffle 9.

The nominal length of the nozzle slot 3 corresponds to the distance between the dashed lines 7a, 7b and the design of the upper edge 9a of the spacer 9 causes the effective length of the nozzle slot to be altered so that the effective lengths of the feed holes 6 (dashed in Fig. 5). The effective length corresponds to the distance between - * “* · the upper edge 9a of the vine 9 and the edge of the nozzle slot outlet (marked with a dashed line: * ·“ 30 Sat 7a). The upper end of the spacer plate 9 is in the free space in the nozzle slot 3, whereby it is preferably bent as shown in the left edge of Fig. 5 to ensure that it remains firmly in place.

The use of the spacer 9 causes the nozzle slot to be shaped such that the width of the upper portion of the nozzle slot after the expansion chamber is greater than the width of the lower portion. This will better compensate for local profile errors such as banners. Likewise, the coating agent particles that may be stuck in the gap will not be as clear as they are stuck in the narrower bottom and the streaking due to nozzle clogging at the top will be attenuated. The embodiment of Figs. 4 and 5 may be conceived to be implemented in conjunction with nozzle slot width adjusting means.

• · »· · * · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·« «« · «I« «I I I I I I I I I I. · • • • • • • • • • • • • • • • • tl «· * •« tl «· * •« ». • · * · ·

Claims (14)

1. Nozzle construction for a flat-beam fiber webs application beam, which nozzle construction exhibits at least two in the fiber web to be coated, running direction one after another arranged nozzle portions (2a-2e), between which is arranged a disc in its upper portion, in the upper portion of the fiber web. direction (transverse direction) extending nozzle gap (3a-3d), which opens into an inclined feeding plane of the upper surface of the nozzle structure, and which nozzle parts are attached to each other with fasteners arranged in their lower region, characterized in that nozzles means by which the nominal length of the MD-directed (in the running direction of the fiber web) can be adjusted in the desired positions of the CD-direction in such that the upper part of said nozzle part is displaced to adjacent nozzle part or away from the resultant change in the desired way of the nozzle gap. CD-oriented width profile. Application beam according to claim 1, characterized in that in the at least one nozzle part the lower part is formed at least one from the underside thereof. including stretching CD-directed control slot (41a-41d), in which it is arranged Itmin- (20a-40d) a control means (40a-40d) with which the width of the control gap can be changed • I ·, v, to change the application bar's lower part MD-rated nominal width, * · · • * j. ·. and thus arranged in the upper part the width of the nozzle gap (3a-3d). ··· · · »• · • ··: j”: The application beam according to claim 2, characterized in that the control gap (4a-4d) extends as a uniform gap substantially along the entire 4-4v nozzle's CD-directed length. 444 9 · • 9 »44 * 4. Application beam according to claim 2 or 3, characterized in that 4 said Itmin at least one control means (40a-40d) consists of a wedge-shaped red 4x. 30, whose insertion into the control slot (41a-41d) fires into an expansion of the control slot, whereby the nozzle gap (3a-3d) decreases in a corresponding manner. Application beam according to claim 2 or 3, characterized in that said at least one control means is a control piece provided with a heating element. An application beam according to claim 2 or 3, characterized in that said at least one control means is a spring-like control piece, wherein the regulation of the width of the nozzle gap (3a-3d) is realized by means of regulation of the tension between the nozzle parts (2a-2e). gan. The application beam according to claim 2 or 3, characterized in that said at least one control means is a control piece based on the use of pressure medium. Application bar according to claim 2 or 3, characterized in that,. said at least one regulating means is constituted by the use of an utterance-based control piece. * · · • · · • • • • »» «« * Application beam according to any of the preceding claims, characterized in that said at least one control means is arranged to change the width of the control slot (41a-41d) and thereby the nozzle gap (3a-3d) within the range. about 1 pm - n. 100 pm. 4. f · • · · • I · * · Application beam according to any of the preceding claims, characterized in that the nozzle gap (3a-3d) is formed by interposing between each other nozzle parts (2a-2e), within the region of their lower parts, an intermediate disk. (8), the thickness of which defines the width of the nozzle gap formed above the intermediate disc. 11. A method for controlling the width profile of a nozzle gap (3a-3d) in a nozzle structure of a planar fiber web's ridging coating device application beam, in the CD web direction (transverse direction) of the fiber web, which nozzle construction exhibits at least two web paths in the fiber web, arranged nozzle portions (2a-2e), which nozzle parts are attached to each other with fasteners arranged in their lower region and between which nozzle portions are formed a nozzle gap which opens into the upper surface of the nozzle structure of the nozzle structure, hence, in the process, the lower part of the nozzle part (2a-2e) is affected in the desired positions by the CD direction, such that the nominal length of said nozzle part's MD-direction (fiber web running direction) is changed profusely, so that the upper part of said nozzle part is moved to the adjacent nozzle portion or away from the oncoming one change in the desired manner of the nozzle gap's CD-directed width profile. Method according to claim 11, characterized in that the nominal length of the nozzle part's mechanical part is changed mechanically, thermally, in the method. . using ultrasound or print media. tai paineväliaineen avulla. • · · * · · *: v 20 • · * • · · .v. A method according to claim 11 or 12, characterized in that in *****: j *. the procedure change the width of the nozzle gap (3a-3d) within the control interval about · * · · 1 pm - n. 100 pm. * · · · • · * · 25 14. A method according to any one of claims 11-13, characterized in that the nozzle gap (3a-3d) is formed by placing between each after each · ···! ...; other arranged nozzle portions (2a, 2b ...), within their lower portions region an intermediate disk (8), the thickness of which defines the width of the nozzle gap formed above the intermediate disk, which opens into the upper surface of the nozzle structure forming the inclined feeder plane. • ·· * · • · ·· *