WO2007108156A1

WO2007108156A1 - Noncontact coater and papermaking machine equipped with the same

Info

Publication number: WO2007108156A1
Application number: PCT/JP2006/321521
Authority: WO
Inventors: Shigenari Horie; Masahiro Sugihara; Hiroshi Miura; Toshiaki Miyakura
Original assignee: Metso Paper, Inc.
Priority date: 2006-03-16
Filing date: 2006-10-27
Publication date: 2007-09-27
Also published as: AT505857B1; JP2007245021A; AT505857A5; DE112006003799T5; JP5015477B2; AT505857A2

Abstract

A noncontact coater and a papermaking machine in each of which the vapor of a wetting liquid is used to form a wetting liquid film on a surface of a web immediately before coating to prevent air inclusion between a coating fluid film and the web surface. The noncontact coater ejects a coating fluid (5) in a curtain form from a slit nozzle (3) and applies this coating fluid (5) to a running web (1) in a non-contact manner. In order that the coater might inhibit the wetting liquid vapor from condensing and prevent the coated surface from having streaks, it has a constitution including: a hood (11) for surrounding a space around the web (1), the hood (11) being not in contact with the web (1) and being disposed upstream in the web running direction from the point (5a) where the coating fluid is delivered to the web (1); a vapor nozzle (12) which is disposed inside the hood (11) and supplies the vapor of a wetting liquid to the web surface; and a heating means which heats the inside of the hood (11).

Description

Specification

Non-contact coating apparatus and paper machine equipped with the same

Technical field

The present invention relates to a non-contact coating apparatus applied to a coater of a papermaking machine, a process facility of an ironmaking machine, and a papermaking machine provided with this apparatus.

Background art

[0002] Non-contact coating apparatuses that apply a coating liquid in which a slit nozzle force in a non-contact state with a web is also applied to the surface of a web such as paper, a resin film, and a steel plate have been developed. In such a non-contact coating apparatus, the coating liquid is generally called a curtain flow coater or a curtain coater because the coating liquid is discharged in a curtain shape vertically below the slit nozzle force.

[0003] In such a non-contact coating apparatus, it is required to form a coating liquid film uniformly on the web and free from entrainment such as air bubbles. For this purpose, it is effective to increase the web collision speed of the coating liquid film, so the distance from the slit nozzle to the web (vertical distance) is set large, and the coating liquid discharged from the slit nozzle and flows down by gravity. Correspondingly, the film web impact speed was increased by the action of gravitational acceleration.

[0004] That is, the web collision speed V of the coating liquid film is equal to the liquid flow velocity V and the slits at the nozzle discharge port.

0 When the distance H from the nozzle to the web is used, v = ^ (v + 2gH), and the distance H is large.

0

As the web collision speed V of the coating liquid film increases, air does not easily enter between the coating liquid film and the web surface, and the coating quality after drying can be improved.

[0005] When the gap H between the slit nozzle and the web is increased and the discharge flow rate Q from the slit nozzle is small, the liquid film curtain is broken from the nozzle discharge port until it reaches the web surface. For this reason, it is difficult to form a relatively thin coating liquid film on the web surface.

[0006] Therefore, the discharge flow rate from the slit nozzle (even if the air is small, even if the distance H from the slit nozzle to the web is set short so that the liquid film curtain does not drip into the rain, it is uniform on the web. In addition, a technique capable of forming a coating liquid film without involving air bubbles or the like has been proposed (for example, Patent Document 1). [0007] In this technique, a wettable liquid film is formed by forming a thin liquid film of the coating liquid on the web surface upstream of the position where the coating liquid discharged from the slit nozzle contacts the web surface. The apparatus is arranged so that a wettable thin liquid film is formed on the web surface before the coating liquid comes into contact with the web surface by the wettable liquid film forming apparatus. As a result, an interfacial tension can be applied between the two liquid free surfaces at the position where the wettable thin liquid film and the coating liquid are in contact with each other, and this interfacial tension causes the coating liquid to pass through the wettable thin liquid film. Thus, it is possible to prevent air from entering between the coating liquid film and the web surface when the collision velocity V of the coating liquid to the web is low. As a selection criterion for this wettability liquid, it is assumed that the interfacial tension between the wettable thin liquid film and the coating liquid is larger than the interfacial tension acting between the surface of the web and the coating liquid.

[0008] Note that the wettability liquid film forming apparatus specifically includes an apparatus that generates vapor of the wettability liquid and a vapor ejection nozzle that ejects the generated wettability liquid vapor toward the web surface. No, it is. By keeping the surface temperature of the web where the steam is jetted below the condensation temperature of the wettable liquid vapor, the wettable liquid vapor ejected from the vapor jet nozzle condenses on the web surface and is A thin liquid film is formed. The liquid film thickness of the wettable thin liquid film is controlled by the amount of vapor ejection, the distance from the condensation start position to the coating liquid contact position, and the like. If the wettable thin liquid film affects the environment, such as organic solvents, a suction box (hood) for collecting steam that has not condensed on the web surface should be surrounded by the steam jet nozzle. Install and collect the vapor in the suction box.

[0009] Further, in recent years, the application of coating liquid onto the web surface by the coating apparatus has been slowing down, so that air (entrained flow) that is caused to rotate along with the web running at high speed is at the coating position. As a result, the entrained flow disturbs the curtain of the coating liquid, causing a problem of adversely affecting the coating. Therefore, there is a need for a technology that suppresses the entrained flow and prevents the curtain from being disturbed, but naturally it is necessary to prevent the occurrence of a new technical problem by suppressing the curtain disturbance. A technique for solving such a problem has been proposed (for example, Patent Document 2).

[0010] This technology is provided on the upstream side of the coating position of the coating liquid on the traveling web. An air blocking plate is placed so that the tip comes into contact with the coating position, and an air suction arch I header is installed upstream of the air blocking plate, and the tip of the air suction arch I nozzle of the air suction header is moved to the air. It is located close to the rear end of the shielding plate. According to this technology, the air that is driven by the running of the web is blocked by the air blocking plate, and is further sucked and removed by the air suction nozzle, so that the outflow in the paper width direction is prevented. Since the paper dust scraped off at the tip of the air is also sucked at the same time by the air suction nozzle, the paper dust does not accumulate at the tip of the air blocking plate.

Patent Document 1: JP-A-6-218313

Patent Document 2: Japanese Patent Laid-Open No. 11 253861

Disclosure of the invention

Problems to be solved by the invention

[0011] By the way, as a more specific example of the technique of Patent Document 1, a configuration as shown in FIG. 6 is conceivable. As shown in FIG. 6, in this configuration, a slit nozzle (applicator nozzle) 3 is provided above the roll 2 at a portion where the web 1 travels while being guided by a guide roll (here, a press roll) 2. The coating liquid is discharged from 3 to the web 1 vertically below.

[0012] The wettability liquid film forming apparatus 40 covers the outer periphery of the part where the web 1 comes into contact with the roll 2 on the web running direction improving flow side than the landing point of the coating liquid on the web 1 The steam hood (corresponding to the suction box) 41 installed in this way, the steam nozzle 42 provided in the steam hood 41 for injecting the vapor of the wettability liquid, and the steam nozzle 42 in the steam hood 41 than the steam nozzle 42 An ejector 43 is provided on the upstream side in the traveling direction and collects the steam in the steam hood 41 outside the steam hood 41 by the ejector effect.

[0013] It should be noted that the downstream end of the steam hood 41 in the web running direction does not interfere even if the coating liquid curtain 5 swings under some influence, that is, the coating formed The liquid curtain 5 is arranged at a position spaced from the curtain 5 so as not to adversely affect the liquid curtain 5. Further, the steam hood 41 is not in contact with the web 1, and a constant gap is formed with respect to the web 1 at the downstream end of the steam hood 41 adjacent to the curtain 5.

[0014] However, when using the technique of Patent Document 1 in this way, there are the following problems. The

In other words, even if the wettable liquid vapor in the hood 41 is sucked by the ejector 43 and collected outside the hood 41, the liquid formed by condensing the wettable liquid vapor remains in the hood 41. S Dripping onto the web 1 causes the wettability liquid to adhere to the web, and the coating liquid supplied thereafter is also applied in the form of streaks or dots. There is a problem that unevenness occurs.

[0015] In addition, when the liquid formed by condensing the wettable liquid vapor in this way in the hood 41 drops onto the web 1, when the web 1 is paper, the dropped liquid breaks the web 1. (Paper break) is triggered.

In addition, since a certain gap is formed between the steam hood 41 and the tube 1 at the downstream end of the steam hood 41, the wettable liquid vapor in the hood 41 flows from the entrained flow of the web 1 through this gap. At the same time, it flows out to the curtain 5 side of the coating liquid, and then rises to the lip part of the applicator nozzle and condenses there. In this case, the wettable liquid condensed in the curtain of the coating liquid As a result of partial mixing, streaks occur on the coated surface as described above.

[0016] With regard to such a problem, in the technique of Patent Document 2, since the tip of the air blocking plate is disposed so as to contact the coating position on the web surface, if this air blocking plate is used, The web accompanying flow itself can be regulated, and the wettable liquid vapor force in the hood 41 does not flow toward the applicator nozzle. However, in this case, since the tip of the air shut-off plate is in direct contact with the web, there is a concern that the air shut-off plate and its peripheral devices may be damaged when the web breaks. The From this point, I would like to assume a configuration in which the rigid member is not in contact with the web.

[0017] The present invention has been devised in view of such problems, and a wettability liquid film is formed on a web surface immediately before coating using a wettability liquid vapor to form a coating liquid film and a web surface. In order to prevent air intrusion between the two, the rigid member is configured to be non-contact with the wettable liquid film forming device web while preventing unevenness on the coated surface. An object is to provide a non-contact coating apparatus and a paper machine equipped with the same.

Means for solving the problem

[0018] In order to achieve the above object, the non-contact coating apparatus of the present invention comprises a slit nozzle force coating. In a non-contact coating apparatus that discharges the liquid in a curtain shape and applies the coating liquid in a non-contact manner to the traveling web !, the web running direction upstream from the landing position of the coating liquid on the web A hood that is disposed on the side and covers the space around the web in a non-contact manner with the web; a steam nozzle that is provided in the hood and that supplies a vapor of a wettable liquid to the web surface; And a heating means for heating.

[0019] Further, as the heating means, for example, an apparatus using electric heat or steam such as an electric heater or a steam jacket mounted on the steam nozzle can be considered.

The steam nozzle preferably injects the steam toward the web surface. Further, an end wall portion of the hood near the coating liquid deposition point is an end wall portion that suppresses the leakage of the vapor from the hood to the vicinity of the coating liquid deposition point, and the coating from the hood. It is preferable to provide a reflux structure for refluxing the vapor that has leaked to the vicinity of the liquid deposition point into the hood!

[0020] The reflux structure is disposed above an edge of the hood near the application liquid deposition point, and is used to suck the vapor leaked from the hood to the vicinity of the coating liquid deposition point. The suction chamber, the communication hole formed so as to communicate between the inside of the hood and the steam suction chamber, and the steam in the hood are sucked and collected on the side where the coating liquid deposition point force is separated. It is preferable that it consists of collection means.

[0021] Further, the hood is provided with an upper wall portion extending in a substantially horizontal direction so as to extend up to the upstream of the application liquid deposition point on the web, and an inner surface of the upper wall portion, It is preferable that the front end force in the vicinity of the coating liquid deposition point is formed by an inclined surface that descends slightly toward the rear.

Furthermore, a steam box that covers at least the steam nozzle and holds the steam sprayed from the steam nozzle on the surface of the web is provided in the hood, and the steam box has a vicinity of the coating liquid deposition point. It is preferable that a plate portion that is disposed substantially horizontally so as to gradually approach the web toward the front end portion of the hood and that extends to immediately before the front end portion of the hood is provided.

[0022] In this case, the hood is close to the coating liquid landing point of the hood from within the steam box, and the steam leaked to the end is separated from the coating liquid landing point in the hood. It is preferable that a vapor recovery means for sucking and recovering in the direction to be provided is provided. In addition, it is preferable that an ejector for sucking an accompanying flow of air generated as the web travels be disposed upstream of the steam nozzle in the hood in the web travel direction! /, .

[0023] In this case, the steam box provided inside the hood, covering at least the steam nozzle and holding the steam sprayed from the steam nozzle on the surface of the web, and the steam box in the hood A partition wall that is provided outside and is divided into a steam recovery space that communicates with the inside of the steam box; and a partition wall that bisects the accompanying flow inflow space into which the accompanying flow flows upstream of the ejector in the web traveling direction; and the steam recovery space A steam recovery means for sucking and recovering the steam inside, and the partition is formed with a minute opening for guiding the entrained flow flowing into the entrained flow inflow space to the steam recovery space. Is preferred.

[0024] Further, it is preferable that a liquid recovery means for recovering the condensed liquid in the hood is provided in the lower portion of the hood! /.

Furthermore, it is preferable that a recovery pan for recovering excess coating liquid discharged to the outside in the width direction of the web is provided below the web in the vicinity of the coating liquid landing point of the hood.

[0025] Further, it is preferable that a doctor that is in sliding contact with the web surface is provided immediately upstream of the hood in the web running direction! /.

Further, the web is configured so that a lateral force of the guide roll is also directed upward and travels along the guide roll, and is separated from the guide roll force at a vertical upper end portion of the guide roll, and the slit nozzle includes the guide nozzle. The hood is disposed so as to land on the web in the vicinity of the vertical upper end of the roll, and the hood covers the upper side force of the guide port and the vicinity of the vertical upper end. It is preferable to be arranged in

[0026] Further, a papermaking machine of the present invention is characterized by including the non-contact coating apparatus according to any one of claims 1 to 13.

The invention's effect [0027] According to the non-contact coating apparatus of the present invention, the vapor of the wettable liquid is supplied to the web surface by the vapor nozzle provided in the hood covering the space around the web. Interfacial tension can be applied between the free surfaces of the two liquids at the position where the formed wettable thin film and the coating liquid come into contact with each other. It is possible to prevent air from entering between the coating liquid film and the web surface even when the impact speed of the coating liquid on the web is low. Therefore, the gap between the slit nozzle and the web is reduced to reduce the discharge flow rate from the slit nozzle so that the liquid film curtain of the coating liquid does not become dripping. It is possible to form a coating liquid film that is thinly wound and relatively thin.

[0028] Since the inside of the hood is heated by the heating means, it is difficult for the vapor to condense in the hood, and the condensed liquid drops on the web, and so-called uneven stripes occur on the coated surface. Such problems can be avoided, and when the web is paper, it can be avoided by inducing web breaks with condensed liquid.

In addition, by jetting steam toward the web surface, wetting liquid can be supplied to the web surface, and the effect of blocking the entrained air flow generated by the web running on the web surface can be obtained. Disturbance in the curtain of the working liquid can be suppressed, which is advantageous for evenly applying the coating liquid. In addition, the leakage of steam from the hood to the coating liquid curtain side due to this accompanying flow can be suppressed. It is also possible to suppress the occurrence of streaks caused by the leaked vapor condensing around the slit nozzle above the coating liquid curtain and dripping on the web.

[0029] In addition, by providing an end wall portion at the end portion of the hood close to the coating liquid deposition point, it is possible to suppress the leakage of steam from the hood to the vicinity of the coating liquid deposition point. By providing this, the steam that has leaked from the hood to the vicinity of the coating liquid deposition point can be recirculated into the hood, thereby condensing the leaked steam around the slit nozzle and dropping it onto the web. It is also possible to suppress the occurrence of streaks caused by lowering.

[0030] In this case, the reflux structure is disposed on the steam suction chamber above the edge of the hood, the communication hole between the steam suction chamber and the hood, and the side where the steam in the hood is separated from the coating liquid deposition point force. Collect by suction If configured with the steam recovery means, the steam that has leaked to the vicinity of the coating liquid deposition point with a simple configuration can be returned to the hood.

In addition, the inclined surface where the inner surface of the upper wall part extending in the substantially horizontal direction extending just upstream of the coating liquid deposition point of the hood slightly descends as it goes to the rear of the front end force near the coating liquid deposition point. As a result, even if a droplet with condensed vapor adheres to the inner surface of the upper wall, which is strong, it will flow out in the direction away from the coating liquid deposition point force along the inclination of the inner surface of the upper wall. Therefore, it is possible to suppress dripping of the powerful droplet onto the web, and it is possible to suppress the generation of streak unevenness.

[0031] A steam box is provided inside the hood, and a substantially horizontal plate portion that gradually approaches the web toward the front end portion in the vicinity of the coating liquid deposition point extends to just before the hood front end portion. By doing so, the wettability liquid can be reliably supplied to the web surface in the steam box. In addition, if the end wall and the reflux structure are provided at the end of the hood, even if steam leaks from the steam box, it is possible to prevent the leaked steam from traveling around the slit nozzle and to suppress the occurrence of the unevenness of the stripe. be able to.

[0032] In the case where the above steam box is provided, the steam bottling force can also be increased by providing a steam recovery means for sucking and collecting the steam in the hood in the direction of separating the coating liquid deposition point force. Even if the steam leaks, it can be prevented that the steam travels around the S slit nozzle.

If an ejector is provided upstream of the steam nozzle in the hood in the web running direction, the ejector can suck the entrained flow of air that occurs as the web travels. It is advantageous to apply the coating liquid uniformly, and it is possible to suppress the leakage of steam from the inside of the hood to the coating liquid curtain due to this entrained flow. Condensation around the slit nozzle above the working liquid curtain can also suppress the occurrence of streak unevenness caused by dripping on the web.

[0033] The ejector is provided inside the hood, a steam box is provided, a partition is provided outside the steam box in the hood, a steam recovery space communicating with the inside of the steam box, and an upstream of the ejector in the web traveling direction. In the entrainment flow inflow space where the side entrainment flow A small opening is formed in the partition wall so that the entrained flow flowing into the entrained flow inflow space is guided to the steam collecting space, and the steam in the vapor recovery space is sucked and collected by the steam collecting means. Thus, while suppressing the influence of the entrained flow to the steam recovery space, the steam in the steam recovery space is smoothly recovered, and the air in the entrained flow inflow space is discharged to the steam recovery space using the steam recovery means. Will be able to.

[0034] In addition, if condensed liquid accumulates in the hood, it may adversely affect the running of the web or increase the burden on the heater to increase the temperature of the hood wall surface. Such a problem can be solved by providing a liquid recovery means for recovering the liquid.

Furthermore, the width of the coating liquid curtain is increased by providing a collection pan that collects the excess coating liquid discharged to the outside in the width direction of the web below the web in the vicinity of the coating liquid deposition point of the hood. When it is larger than the width, the coating liquid is prevented from splashing outside the web in the width direction.

[0035] Further, if a doctor slidingly contacting the surface of the web is provided immediately upstream of the hood in the web running direction, it is possible to suppress the accompanying flow of the web that does not adversely affect the coating.

Web force When the guide roll is configured to run from the side of the guide roll upward along the guide roll and leave the guide roll force at the vertical upper end of the guide roll, the slit nozzle is placed near the vertical upper end of the guide roll. It is arranged so that the coating liquid is landed on the web, and the hood is covered from the side of the guide roll to the upper side and the vicinity of the vertical upper end, thereby supplying the wettable thin liquid to the web surface and Subsequent coating can be performed efficiently.

Brief Description of Drawings

[0036] FIG. 1 is a cross-sectional view showing a non-contact coating apparatus according to one embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a steam nozzle and an ejector portion of a non-contact coating apparatus that works according to an embodiment of the present invention.

[FIG. 3] FIGS. 3 (a) and 3 (a) are diagrams showing the heating means of the non-contact coating apparatus according to one embodiment of the present invention, and FIG. 3 (a) shows the case surface of the ejector. Fig. 3 (b) is a cross-sectional view of the ejector case [B-B cross-sectional view of Fig. 3 (a)]. [FIG. 4] FIG. 4 is an enlarged cross-sectional view showing a vapor reflux structure portion of a non-contact coating apparatus that is effective in one embodiment of the present invention.

FIG. 5 is a perspective view showing a collection pan of a non-contact coating apparatus that works on one embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view showing a non-contact coating apparatus created in the process of devising the present invention.

Explanation of symbols

1 Web (web-like paper)

2 Breast roll (guide roll)

3 Slit nozzle (applicator nozzle)

5 Coating liquid (Coating liquid curtain)

5a Landing point

11 Food

11a Hood body

l ib Hood tip plate (upper wall)

11c Hood entrance plate

12 Steam nozzle

12a Steam nozzle 12 injection port

13 Ejecta

13a Ejector 13 suction port

14 Edge plate (end wall)

15 Reflux structure

15a Angle material

15b Steam suction chamber

15c communication hole

16 Steam box

16a Plate part

17 Bulkhead 17a opening

18 Steam recovery space

19 Entrained inflow space

20 Doctor

21 Collection pan

24 heater (heating means)

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 5 show a non-contact coating apparatus according to an embodiment of the present invention. FIG. 1 is a sectional view thereof, FIG. 2 is an enlarged view of a steam nozzle and an ejector portion thereof, and FIG. FIG. 3 (a) is a view showing the heating means, FIG. 4 is an enlarged view of the steam reflux structure portion, and FIG. 5 is a perspective view showing the recovery pan.

The non-contact coating apparatus covered in the present embodiment is provided as a coater of a papermaking machine. A web (web-like paper) 1 is installed in a portion that runs along a breast roll (guide roll) 2. ing. That is, the web 1 comes into contact with the circumferential surface of the breast roll 2 from below the breast roll 2, travels along the circumferential surface of the breast roll 2 from the side of the breast roll 2, and moves vertically. Drive away from breast roll 2 at the top edge.

[0039] The slit nozzle (applicator nozzle) 3 is arranged above the vicinity of the vertical upper end of the breast roll 2 where the web 1 is separated from the breast roll 2, and the jet direction is set so as to discharge the coating liquid downward. Is set. Here, the curtain-shaped coating liquid 5 discharged from the slit nozzle 3 is configured to land on the web 1 with the position slightly downstream of the part where the web 1 is separated from the breast roll 2 as the landing point 5a. Is done.

[0040] A hood 11 that covers the space around the web 1 that is in contact with the breast roll 2 and that is in contact with the breast roll 2 is located upstream of the landing position 5a of the coating liquid on the web 1 in the web traveling direction. Arranged in contact. The hood 11 has a substantially U-shaped cross section, a hood main body 11a, a hood tip plate (upper wall) l ib coupled to the downstream side of the hood main body 11a in the web running direction, and the hood main body 11a on the upstream side of the web running direction. Combined hood entrance plate 11c and these hoods And a side plate (not shown) coupled to both ends of each of the plates l ib and 11c.

[0041] The front end plate l ib of the hood is slightly inclined from the horizontal so that the front end force of the hood 11 near the coating liquid deposition point 5a is slightly lowered toward the rear (right side in FIG. 1). Arranged. Therefore, the inner surface (downward surface) of the hood tip plate l ib is also formed by an inclined surface that slightly falls downward. The web 1 travels away from the breast roll 2 slightly upward from the horizontal, and the inclination of the hood tip plate l ib is slightly smaller than the inclination of the web 1 in the traveling direction. Therefore, the hood tip plate 1 lb is positioned so that the base is closest to the web 1 at the tip portion.

Further, an edge plate (end wall portion) 14 is provided at the tip of the hood tip plate l ib so as to approach the surface of the web 1. The edge plate 14 brings the tip of the hood 11 close to the surface of the web 1, and the tip of the hood entrance plate 11 c also approaches the surface of the web 1. This is a force for partitioning the inside and outside of the hood 11. A minimum tally (a few millimeters) is provided to ensure that the hood 11 is kept in a non-contact state with respect to the web 1 on which it travels. . Further, even when the web 1 is cut, the gap can be used for processing such as paper passing.

In such a hood 11, an ejector 13 is provided on the upstream side in the web traveling direction for sucking the accompanying air flow generated when the web 1 travels. Further, a steam nozzle 12 for supplying the wet liquid vapor to the surface of the web 1 is provided downstream of the ejector 13 in the web running direction. Further, a steam box 16 is provided around the steam nozzle 12 in the hood 11 to cover the steam nozzle 12 and hold the steam sprayed from the steam nozzle 12 on the surface of the web 1.

As shown in FIGS. 1 and 2, the suction port 13a of the ejector 13 is disposed at a position close to the surface of the web 1 and efficiently sucks the entrained air flow along the surface of the web 1 (see arrow 13b). Oriented toward the upstream side of the web running direction as possible.

Further, the steam nozzle 12 is arranged with the injection port 12a facing the surface of the web 1, and the steam is directly sprayed onto the surface of the web 1 (see arrow 12b).

[0045] The steam box 16 is connected to the case of the ejector 13 on the upstream side in the web running direction. In the downstream of the web running direction, it is arranged approximately horizontally so as to gradually approach the web 1 toward the front end of the steam box 16 near the coating liquid deposition point 5a and extends to just before the front end of the hood 11. The plate portion 16a is provided.

As shown in FIGS. 3 (a) and 3 (a), the surface of the case of the steam box 16 and the ejector 13 is provided with an electrothermal plate heater or hot wire heater as a heating means. The inside of the hood 11 is kept at a high temperature (at least 100 ° C or higher). In the example shown in FIGS. 3 (a) and 3 (a), a groove is dug in the surface of the case 13c of the ejector 13, and the heater 24 is embedded in the groove. In addition, as a heating means, a steam jacket that allows high-temperature steam to flow inside may be applied to the case of the steam box 16 or the case of the steam nozzle 12 or the ejector 13.

[0046] Due to the case of the steam box 16 and the ejector 13, the inside of the hood 11 is divided into the inside and outside of the steam box 16. The partition 17 that bisects this space is provided outside the steam box 16. Is arranged. Due to this partition wall 17, the steam recovery space 18 that communicates with the inside of the steam box 16 through a minute opening (a clearance of about several millimeters) at the front end of the steam box 16 and the web travel more than the ejector 13. It is divided into an accompanying flow inflow space 19 including a portion into which an accompanying flow flows in on the upstream side.

[0047] However, a minute opening (for example, a gap of about 1 mm) 17a for guiding the entrained flow flowing into the entrained flow inflow space 19 to the steam recovery space 18 is formed at the end of the partition wall 17 on the steam box 16 side. ing.

Then, as shown by an arrow in FIG. 1, a steam recovery means (not shown) that sucks and recovers the gas containing the steam in the steam recovery space 18 to the side away from the coating liquid curtain 5 (right side in FIG. 1). And a liquid recovery means (not shown) for recovering the liquid containing the wettability liquid condensed and liquefied in the hood 11 by its own weight.

Further, as shown in FIGS. 1 and 2, an L-shaped angle member 15a is coupled to the upper surface of the tip of the hood tip plate l ib in a sectional view, and the angle member 15a and the hood tip plate l A vapor suction chamber 15b opened toward the coating liquid curtain 5 is formed by the tip of ib. In addition, a communication hole 15c for communicating the vapor suction chamber 15b and the inside of the hood 11 is formed in the distal end portion of the hood distal plate Lib constituting the lower surface of the vapor suction chamber 15b. [0049] Then, the steam that has leaked from the inside of the hood 11 to the vicinity of the coating liquid deposition point 5a by the steam suction chamber 15b, the communication hole 15c, and the steam recovery means described above is put into the hood 11. A reflux structure 15 for reflux is formed. That is, the tip force of the hood 11 vapor that has leaked to the vicinity of the coating liquid deposition point 5a tries to rise along the coating liquid curtain 5 so as to be directed toward the slit nozzle 3 (the arrow in FIG. 4). 22a), however, a steam suction chamber 15b is provided at the top of the tip of the hood 11, and a communication hole 15c that connects the steam suction chamber 15b and the inside of the hood 11 is provided. The suction force to the side away from the coating liquid curtain 5 (see arrows 22d and 22e in Fig. 1) causes a gas flow as shown by arrows 22b and 22c in Fig. To reflux.

In addition, as shown in FIGS. 1, 4, and 5, the excess coating liquid discharged to the outside in the width direction of the web 1 is placed below the vicinity of the coating liquid landing point 5a of the web 1. A collection pan 21 for collection is provided. This collection pan 21 is arranged so that the tip is inserted between the web 1 and the breast roll 2 below the coating liquid landing point 5a, and the web width force is larger than the width of the coating liquid curtain 5. In this case, the coating liquid 5 at the curtain end 5b that falls without being supplied to the web 1 is collected. The lower surface of the recovery pan 21 has an inclined surface that descends to the side where the recovery point force is also separated (left side in Figs. 1 and 4), and excess coating liquid is recovered along this inclination (Fig. 4 arrow 21a).

Furthermore, in the present embodiment, a doctor 20 that is in sliding contact with the surface of the web 1 that is in contact with the breast roll 2 is provided downstream of the hood 11 in the web traveling direction.

Since the non-contact coating apparatus according to one embodiment of the present invention is configured as described above, the doctor 20 first comes into sliding contact with the web 1 surface against the web 1 traveling along the breast roll 2. As a result, paper dust on the surface of the web 1 is scraped off, and the downstream flow of the entrained flow that occurs as the web 1 travels is suppressed.

[0052] After that, the web 1 enters the hood 11, and first, in the entrained flow inflow space 19, the entrained flow that cannot be completely blocked by the doctor 20 is converted into a suction force by the minute openings 17a and the steam recovery means. Use it to guide it to the steam recovery space 18 (see arrows 23a, 23b, 23c in Fig. 1) for recovery. However, if the entrained flow inflow space 19 and the steam recovery space 18 are connected, a strong air flow from the entrained flow inflow space 19 may interfere with the suction and recovery of the steam by the steam recovery means. However, since the opening between the entrained flow inflow space 19 and the steam recovery space 18 is minute, there is no such problem.

[0053] Further, the web 1 is then suctioned and removed by the suction effect of the ejector 13.

In this way, the entrained flow is greatly reduced, and the vapor of the wettable liquid is jetted from the vapor nozzle 12 onto the surface of the web 1. At this time, since the steam is directly sprayed onto the surface of the web 1, a wettable thin liquid film can be reliably formed on the surface of the web 1. Further, by spraying the steam toward the surface of the web 1, an effect of blocking the entrained air flow generated by the web 1 traveling on the surface of the web 1 can be obtained.

As a result, an interfacial tension can be applied between the free surfaces of the wettable thin liquid film and the coating liquid at the position where the web 1 and the coating liquid are in contact with each other. Due to this interfacial tension, the coating liquid is attracted toward the surface of the web 1 through the wettable thin liquid film, and the coating liquid film and the web 1 even when the collision speed of the coating liquid to the web 1 is small. It is possible to prevent air from entering the surface.

Therefore, the gap between the slit nozzle 3 and the web 1 is reduced to suppress the discharge flow rate from the slit nozzle 3 so that the liquid film curtain 5 of the coating liquid does not become dripping, while being uniformly on the web 1. It is possible to form a coating liquid film having a relatively thin wrapping force of air bubbles and the like.

[0055] Since the inside of the hood 1 is heated by the heating means, it is difficult for the vapor to condense in the hood 1, and the condensed liquid drops on the web 1 to generate so-called uneven stripes on the coated surface. If the paper web 1 breaks due to the condensed liquid, it is possible to avoid the problem V.

In addition, the web 1 that has advanced to the coating liquid deposition point 5a can significantly reduce the entrained flow upstream, so that the coating liquid curtain 5 is prevented from being disturbed by the accompanying flow at the coating liquid application stage. be able to. This is advantageous for uniformly applying the coating liquid, and also prevents the leakage of steam from the hood 11 to the coating liquid curtain 5 side due to the accompanying flow, and the leaked steam is applied to the coating liquid curtain 5. Condensation occurs around the slit nozzle 3 above and drops on the web 1 to suppress the generation of uneven stripes. [0056] Further, by providing an edge plate (end wall portion) 14 at the end of the hood 11 near the coating liquid deposition point 5a, steam leakage from the hood 11 to the vicinity of the coating liquid deposition point is prevented. Furthermore, the recirculation structure 15 allows the vapor that has leaked from the hood 11 to the vicinity of the coating liquid deposition point 5a to be recirculated into the hood 11, thereby causing the leaked steam to be slit. It is also possible to suppress the occurrence of streaks caused by condensation around the nozzle 3 and dropping onto the web 1.

[0057] Further, the reflux structure 15 has a vapor suction chamber 15b above the edge of the hood, a communication hole 15c between the vapor suction chamber 15b and the hood 11, and vapor in the hood 11 applied to the coating liquid. Since the steam collecting means for sucking and collecting at the point force separating side, the steam leaked to the vicinity of the coating liquid deposition point 5 a can be recirculated into the hood 11 with a simple configuration.

In addition, the inner surface (downward surface) of the hood tip plate 1 lb that extends to the upstream of the coating liquid deposit point 5a of the hood 11 is formed by an inclined surface that slightly descends toward the rear. l Even if droplets with condensed vapor adhere to the inner surface of the ib, the liquid flows out backward, that is, in a direction away from the coating liquid deposition point 5a, along the inclination of the inner surface. Can prevent dripping on the top and suppress the occurrence of unevenness

[0058] In addition, the steam box 16 provided in the hood 11 is provided with a plate portion 16a extending to a position immediately before the front end of the hood 11, so that the surface of the web 1 in the steam box 16 has wettability liquid. And power can be supplied efficiently.

In addition, if condensed liquid accumulates in the hood 11, it will adversely affect the running of the web 1 or increase the burden on the heater to raise the temperature inside the hood 11. Such a problem can be solved by providing a liquid recovery means for recovering the condensed liquid.

[0059] Furthermore, a coating liquid curtain is provided below the web 1 in the vicinity of the coating liquid deposition point 5a by including a collection pan 21 that collects excess coating liquid discharged to the outside in the width direction of the web 1. When the width of 5 is larger than the web width, the coating liquid is prevented from splashing outside the web 1 in the width direction.

[0060] While the embodiments of the present invention have been described above, the present invention is limited to the above-described embodiments. However, various modifications can be made without departing from the spirit of the present invention, or only a part of the configuration can be used.

[0061] For example, in the above-described embodiment, the non-contact coating apparatus is provided at a location where the web travels while being guided by the breast roll. However, the installation location is not limited to this, and the hood shape is not limited thereto. Depending on the configuration.

In the above embodiment, the non-contact coating apparatus applied to the coater of the papermaking machine has been described. However, the object of coating is not limited to this, and the present invention is also applicable to coating of webs such as resin films and steel plates. And may be applied to process equipment of a steelmaking machine.

Industrial applicability

[0062] The present invention can be applied to a coater of a papermaking machine because a coating liquid film can be formed uniformly on a web and a relatively thin rolling force of air bubbles or the like can be formed. Although it is suitable for non-contact coating equipment, the object of coating is not limited to this, and it can also be applied to the coating of steel sheets and other webs by applying it to the process equipment of steelmaking machinery. It can also be applied to coating.

Claims

The scope of the claims

[1] A non-contact coating device that dispenses the coating liquid (5) from the slit nozzle (3) in the form of a curtain and applies the coating liquid (5) to the running web (1) without contact! Hurry,

The web (1) is disposed on the upstream side in the running direction of the web (1) from the landing point (5a) of the coating liquid (5), and is in non-contact with the web (1). ) Hood that covers the surrounding space (

11) and

A steam nozzle (provided in the hood (11)) for supplying steam to the surface of the hub (1)

12) and

And heating means (24) for heating the inside of the hood (11).

A non-contact coating apparatus characterized by that.

[2] The steam nozzle (12) injects the steam toward the surface of the web (1).

The non-contact coating apparatus according to claim 1, wherein:

[3] At the end of the hood (11) near the coating liquid deposition point (5a), the vapor leaks from the hood (11) to the vicinity of the coating liquid deposition point (5a). An end wall (14) to be suppressed, and a reflux structure for recirculating the vapor leaked from the inside of the hood (11) to the vicinity of the coating liquid deposition point (5a) into the hood (11) ( 15) is provided

The non-contact coating apparatus according to claim 1 or 2, wherein

[4] The reflux structure (15) is disposed above an edge of the hood (11) close to the coating liquid landing point (5a), and from within the hood (11) to the coating liquid landing point. (5a) The steam suction chamber (15b) for sucking the steam leaked to the vicinity, and the communication formed to communicate between the inside of the hood (11) and the steam suction chamber (15b) It is composed of a hole (15c) and a steam collecting means for sucking and collecting the steam in the hood (11) to the side separated from the coating liquid deposition point (5a).

The non-contact coating apparatus according to claim 3, wherein:

[5] The hood (11) has an upper wall portion (1 la) extending in a substantially horizontal direction so as to extend up to the upstream of the coating liquid deposition point (5a) to the web (1). Provided,

The inner surface of the upper wall portion (1 la) is formed by an inclined surface that slightly falls as it goes rearward from the front end portion in the vicinity of the coating liquid deposition point (5a). The non-contact coating apparatus according to claim 1, wherein the force is any one of claims 1 to 4.

[6] A steam box (16) that covers at least the steam nozzle (12) inside the hood (11) and holds the steam sprayed from the steam nozzle (12) on the surface of the web (1). Is provided,

The steam box (16) is disposed substantially horizontally so as to gradually approach the web (1) toward the front end near the coating liquid deposition point (5a), and the front end of the hood (11). Plate part (16a) extended to just before

The non-contact coating apparatus according to claim 1, wherein the force is any one of claims 1 to 5.

[7] In the hood (11), the steam leaking from the inside of the steam box (16) to the end of the hood (11) near the application liquid deposition point (5a) is supplied to the hood (11). Vapor recovery means is provided for suctioning and recovering the coating liquid landing point (5a) force in the direction of separation

The non-contact coating apparatus according to claim 6, wherein:

[8] On the upstream side of the web (1) in the running direction from the steam nozzle (12) in the hood (11), the accompanying flow of air generated by the running of the web (1) is absorbed. I ejector (13) is installed

The non-contact coating apparatus according to any one of claims 1 to 7, wherein

[9] A steam box (16) provided inside the hood (11), covers at least the steam nozzle (12), and holds the steam sprayed from the steam nozzle (12) on the surface of the web (1). When,

A steam recovery space (18) provided outside the steam box (16) in the hood (11) and communicating with the inside of the steam box (16), and the web (1) than the ejector (13). A partition wall (17) that bisects the entrained flow inflow space (19) into which the entrained flow flows upstream in the traveling direction;

Steam recovery means for sucking and recovering the steam in the steam recovery space (18); A small opening (17a) is formed to guide the

The non-contact coating apparatus according to claim 8, wherein:

[10] A liquid recovery means for recovering the condensed liquid in the hood (11) is provided at the lower part of the hood (11).

The non-contact coating apparatus according to any one of claims 1 to 9, wherein the apparatus is a non-contact coating apparatus.

[11] Under the web (1) in the vicinity of the coating liquid deposition point of the hood (11), a collection for recovering excess coating liquid discharged to the outside in the width direction of the hub (1). Pan (21) is provided

The non-contact coating apparatus according to any one of claims 1 to 0, wherein:

[12] A doctor (20) that is slidably contacted with the surface of the web (1) is provided immediately upstream of the hood (11) in the traveling direction of the web (1)!

The non-contact coating apparatus according to claim 1, wherein the non-contact coating apparatus is characterized by.

[13] The web (1) travels along the guide roll (2) from the side to the upper side of the guide roll (2), and the guide roll (2) ) Configured to separate forces,

The slit nozzle (3) is arranged to land the coating liquid (5) on the web (1) in the vicinity of the vertical upper end of the guide roll (2),

The hood (11) is disposed so as to cover from the side of the guide roll (2) to the upper side and the vicinity of the vertical upper end.

The non-contact coating apparatus according to any one of claims 1 to 12, wherein the non-contact coating apparatus is characterized in that

[14] The non-contact coating apparatus according to any one of claims 1 to 13 is provided.

A paper machine characterized by that.