JP2005324193A - Apparatus for applying at least one kind of liquid or paste like coating medium on one surface or both surfaces in moving surfaces - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for applying at least one kind of a liquid or paste like coating medium on one surface or both surfaces in moving surfaces. <P>SOLUTION: This apparatus has a curtain applicator 13 for applying at least one coating medium 11 and at least one collecting device 14 for collecting at least one kind of the coating medium in the start- and stop-phases of the coating work of the curtain applicator 13. The curtain applicator 13 discharges at least one kind of the coating medium 11 as a curtain moving substantially under gravity in the coating work on the moving surface. As the surface, the surface of a paper web, a board web or other fiber web is used in case of direct coating and a transfer element, and preferably an applicator roll for discharging at least one kind of the coating medium 11 on the surface of the fiber web is provided in case of indirect coating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is an apparatus for applying at least one type of liquid or pasty application medium to one or both sides of a moving surface, and has a curtain applicator for applying at least one type of application medium, Having at least one collection device for collecting at least one application medium during the start and stop phases of the coating operation of the curtain applicator, wherein the curtain applicator is substantially under gravity during the coating operation Release at least one application medium on a moving surface as a moving curtain, the surface being a paper web, cardboard web or other fiber web surface in the case of direct application, in the case of indirect application Transfer device, preferably relating to an apparatus that is the face of an applicator roll that releases at least one application medium onto the face of a fibrous web .

  In order for the fibrous web to be coated to be provided with the application medium over the maximum length, it appears obvious that the collecting device is moved under the curtain as quickly as possible at the start of the coating operation. However, if the collection device is too fast to move under the thin curtain at the start of the coating operation, the thin curtain will continue to travel in the direction of movement of the collection device by the air around the collection device, so that the application medium Reach the outer edge and dripping onto the fiber web. As a result of the dripping coating material, poor application occurs. If the coating material does not drip and dries at the outer edge of the collection device, the dry color will peel off and fall onto the fiber web, resulting in poor application as well. As a result of the deflection of the curtain from the vertical, the curtain swings back and forth, and as a result, application defects likewise occur in the form of regions having different thickness coatings. In this way, areas with excessively thin coating thickness and areas with very thick coating thickness can be produced. Very thick coating thickness regions can cause fiber web breakage and present drying problems. This requires either superior machinist skills or complex dryer control techniques, because dryers for drying such areas must operate at higher drying power than a period of time. In the opposite case, at the beginning of the coating operation, if the thin curtain is too late to move away from the collection device, the thin curtain is attracted to the collection device by adhesive force. The attraction of the curtain to the collecting device likewise means that the application medium reaches the outer edge of the collecting device. The application medium flows to the outer edge of the collection device and drips onto the fibrous web. Furthermore, in this case as well, the curtain swings, causing the above-mentioned problems. The rocking can further contaminate the extraction device located in the vicinity of the curtain applicator in order to extract the air layer conveyed along the high-speed moving fiber web.

  The object of the present invention is to improve an apparatus of the type mentioned at the outset in that, at the start of the coating operation, application defects are reduced and the fibrous web is applied over its maximum length.

  The present invention achieves the object described by an apparatus of the type mentioned at the outset, and according to the invention, at the start of the coating operation, the curtain applicator and said at least one The collection devices can be moved relative to each other.

  Assuming the relative speed between the curtain applicator and the collection device in this speed range, application failure is significantly reduced. Specifically, the application medium is prevented from reaching the outer edge of the collection device and dripping onto the fibrous web. Furthermore, the swing of the thin curtain is also negligible or not even recognized. Thus, increasing requirements regarding the risk of drying and undesirable breakage of the fibrous web are also eliminated. Furthermore, this speed range ensures that the fiber web to be coated is provided with the application medium over its maximum length.

  Particularly good results are achieved when the curtain applicator and the collection device are moved relative to each other at a relative speed of 100 mm / sec to 150 mm / sec.

  The speed range according to the invention is only important at the start of the coating operation, but can also be used in the case of interruption of the coating operation. However, in the event of an interruption of the coating operation, the curtain applicator and collection device can also move towards each other at a higher speed. In particular in the case of fiber web breakage, it is advantageous to move the curtain applicator and the collection device towards each other at maximum speed in order to collect the curtain as quickly as possible.

  It may be advantageous for the speed of the fibrous web to be at least 500 m / min. However, a web speed of 2500 m / min is also possible. At such web speeds, the relative speed between the curtain applicator according to the invention and the collection device is fast enough to provide the application medium on the fibrous web to be coated over the maximum length.

  In a development of the invention, the relative speed between the curtain applicator according to the invention and the collecting device can also be realized with a drop speed of at least 50 m / min. Even at the current maximum drop speed of 200 m / min, a relative speed between the curtain applicator according to the invention and the collecting device can be realized.

  The relative speed of the curtain applicator and the at least one collection device may be constant or variable. Thus, for example, in the case of a variable relative speed, the relative speed is slower at the beginning and at the end of the relative movement between the curtain applicator and the collecting device its maximum speed between the two end points of movement. It may be. As a result, undesirable swinging can be further reduced.

  In a preferred embodiment, the at least one collection device comprises a trough with an edge facing the curtain during the coating operation, and the edge can have a slope of at least 10 ° relative to the horizontal. A gradient of at least 10 ° avoids the situation where air enters the application medium and forms bubbles in the application medium when the application medium hits the edge, resulting in poor application. The exact slope of the gradient depends on the application medium and the formulation used, respectively. During the standby state, and thus the state in which the fibrous web is not coated, the curtain is tilted at least 10 ° and falls continuously on the edge, preferably several millimeters higher. Since the curtain falls on the outer edge of the collection device during the standby state, very little relative movement between the curtain applicator and the collection device is required to start the coating operation from the standby state and interrupt the coating operation. is there.

  Conveniently, the edge gradient can be combined with a trough base having a gradient of less than 10 °. In order to ensure that the collecting device does not collide with the fibrous web passing under the collecting device, but the collected application medium is satisfactorily removed, the trough base generally has a slope of 1 ° to 5 °.

  The edge of the edge may be knife-shaped. This allows the collection medium to move into the curtain in the case of an interruption of the coating operation and to leave the edge of the collection device when leaving the curtain under the coating operation. Make sure it doesn't flow out of the outside.

  For this reason, it is advantageous if a surface falling towards the inside of the trough is provided between the knife-shaped edge and the inner surface of the edge.

  In the text which follows, exemplary embodiments of the device according to the invention are explained in more detail by means of the attached drawings.

  FIG. 1 shows an apparatus 10 for applying an application medium 11 that forms a curtain on one or both sides of a fibrous web 12. The apparatus 10 has a curtain applicator 13 for applying the application medium 11 and a trough-shaped collection device 14 for collecting the application medium 11. The curtain applicator 13 and the collection device 14 can be moved relative to each other along the direction of travel arrow 15 if desired. In this case, the curtain applicator 13 may remain stationary and the collection device 14 may be movable, or the collection device 14 may remain stationary and the curtain applicator 13 may move. In yet another example, it is also possible to move the curtain applicator 13 and the collection device 14 simultaneously. According to the present invention, the curtain applicator 13 and the collection device 14 move relative to each other at a speed of 20 mm / second to 200 mm / second. Given the relative speed between the curtain applicator 13 and the collection device 14 in this speed range, an optimum application is achieved and at the same time the fibrous web 12 is applied over its maximum length.

  The trough-shaped collecting device 14 comprises an edge 16 having a slope with an inclination angle β of at least 10 °. A gradient of at least 10 ° avoids a situation where air enters the application medium 11 when the application medium 11 hits the edge 16 and can result in application failure. During the waiting state of the collecting device 14, i.e. while the fibrous web 12 is not coated, as shown, the application medium 11 continuously falls on an edge 16 that is inclined at least 10 [deg.]. Since the application medium 11 falls on the outer edge 16 during the standby state, the curtain applicator 13 and / or the collecting device 14 starts the coating operation from the standby state (starting phase) or interrupts the coating operation ( In the stop phase), it must be covered for a short distance.

  The edge 16 is preferably only a few millimeters higher. In order to ensure that the collecting device 14 does not collide with the fibrous web 12, but the collected application medium is satisfactorily removed, the slope of the edge 16 is usually a trough base having a slope of an inclination angle α of 1 ° to 5 ° Combine with 17.

  The edge 16 has a knife-shaped edge 20 (see FIG. 2). The knife-shaped edge 20 has a surface 21 that falls towards the inside of the trough at an angle δ. When the surface 21 hits the edge 20, the application medium 11 is guided inside the trough and the collection device 14 is moved from under the curtain formed by the application medium 11 falling in the event of a coating operation interruption. Alternatively, it is ensured that the application medium 11 does not flow outside the edge 16 if it is moved from under the curtain at the start of the coating operation.

1 shows a cross-sectional view of a device according to the invention. Fig. 2 shows a detailed view of the knife-shaped edge of the device of Fig. 1;

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Apparatus 11 Application | coating medium 12 Fiber web 13 Curtain applicator 14 Collecting device 15 Direction of movement 16 Edge 17 Trough base 20 Edge 21 Surface α Inclination angle β Inclination angle δ Angle

Claims (10)

A curtain applicator (10) for applying at least one type of liquid or paste-like application medium (11) to one or both sides of the moving surface, wherein the at least one type of application medium (11) is applied. At least one collecting device (14) for collecting the at least one application medium (11) during the start and stop phases of the coating operation of the curtain applicator (13) The curtain applicator (13) emits the at least one application medium (11) onto the moving surface as a curtain that moves substantially under gravity during the coating operation, the surface being The surface of a paper web, cardboard web or other fiber web (12) in the case of direct application, transfer element, preferably in the case of indirect application , In the at least one device is the surface of the applicator roll to release onto the surface of the application medium (11) the fibrous web (12) (10),
The curtain applicator (13) and the at least one collection device (14) are moved relative to each other during the start and stop phases of the coating operation at a speed of 20 mm / sec to 200 mm / sec. A device (10) characterized in that   The device (10) according to claim 1, characterized in that the speed of the fibrous web (12) is at least 300 m / min.   Device (10) according to claim 1 or 2, characterized in that the curtain has a drop speed of at least 50 m / min.   The apparatus (10) according to any one of the preceding claims, characterized in that the relative speed of the curtain applicator (13) and the at least one collecting device (14) is constant or variable.   The at least one collecting device (14) has a trough with an facing edge (16), the edge (16) having a slope or inclination angle β of at least 10 ° relative to an imaginary horizontal line; Device (10) according to any one of the preceding claims.   Device (6) according to claim 5, characterized in that the gradient of the edge (16) is combined with a trough base (17) having a gradient of less than 10 °, preferably an inclination angle α of 1 ° to 5 °. 10).   Device (10) according to claim 5 or 6, characterized in that the edge (16) faces the curtain (11) during the coating operation.   Device (10) according to any one of claims 5 to 7, characterized in that one edge (20) of the edge (16) is knife-shaped.   9. A surface (21) falling towards the inside of the trough at an angle [delta] is provided between the knife-shaped edge (20) and the inner surface of the edge (16). Device (10).   When the collection device (14) is in the standby position, or when the curtain applicator (13) is in the start or stop phase, the application medium (11) discharged as a curtain will be in the collection device (14). Device (10) according to any one of claims 5 to 9, characterized in that it falls on the edge (16).

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