JPH0620498U - Air knife for paper machine - Google Patents

Abstract

(57) [Summary] [Object] With regard to an air knife of a papermaking coating machine, it is an object of the present invention to provide an air knife that has a particularly simple structure and does not cause uneven coating. [Arrangement] An air knife of a papermaking coating machine for adjusting a coating amount applied to a paper surface with an applicator roll to a predetermined coating amount with an air knife equipped with an air outlet, wherein the inside of the air outlet of the air knife is: A rectifying plate having a large number of through holes opened toward the outlet was arranged.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a papermaking coating machine for coating a paper surface with a paint or the like at the time of papermaking, and particularly to an air knife for adjusting the coating amount of the coating material applied to the paper surface by using air.

[0002]

[Prior art]

 As is well known, paint is applied at the time of paper making to improve the smoothness of the paper surface and the printing characteristics. A rod coater, a blade coater, an air knife coater, etc. are generally used as the coating device. Among the coaters, the air knife coater coats the paint supplied to the color van on the paper surface with an applicator roll, and the air is blown out by an air knife installed on the downstream side of the applicator roll to achieve a predetermined coating amount. To adjust.

[0003]

[Problems to be solved by the device]

 By the way, the air knife is a hollow body as shown in FIG. 6, and the lips 2 and 2 are attached to the tip ends of the upper and lower knives 1 and 1 arranged facing each other to form an air outlet 3 in the width direction, The structure is such that air supplied from the air pipes connected to both side plates to the hollow portion 4 is discharged from the outlet, and a plurality of air gaps are provided between the upper and lower knives 1 and 1 to reinforce the knives. Reinforcing ribs 5 are provided. In the air knife of the above structure, when air is supplied from the air pipes arranged on both side plates, a turbulent flow is generated near the air confluence point at the center of the knife or near the ribs provided for the purpose of reinforcing the knife. Discharge as it is. The air knife sprays the paint applied to the surface of the paper from the outlet in a direction perpendicular to the paper and with a uniform pressure in the width direction to scrape off the excess paint applied and smooth it. When the air is jetted in a turbulent state as described above, the air is not jetted with a uniform pressure in the width direction, so that unevenness, that is, coating unevenness occurs on the coating surface. The present invention has been made in order to eliminate the above-mentioned conventional problems, and an object thereof is to provide an air knife which has a simple structure and does not cause uneven coating.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention is an air knife for a papermaking coating machine, which adjusts a coating amount applied to a paper surface with an applicator roll to a predetermined coating amount with an air knife equipped with an air outlet. Inside the air outlet, a straightening plate having a large number of through holes that open toward the outlet is provided. In the air knife of the above construction, the straightening vane is arranged inside the air blowing port, so that the air passes through the through hole of the straightening vane, becomes a laminar flow of the same pressure, and is jetted from the blowing port onto the coating surface to paint. And scrape it evenly to smooth it. Therefore, there is no uneven coating on the coated surface.

[0005]

【Example】

 The present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a schematic side view of a paper coating machine equipped with an air knife according to an embodiment of the present invention, in which reference numeral 10 is a coating machine. The coating machine 10 comprises a transfer roll 11, an applicator roll 12, a color pan 13, a metering roll 14, a breast roll 15, a catch pan 16 and an air knife 17, and the running base paper P is filled with the color pan 13. Is applied with an applicator roll 12, and the paint is evenly leveled and smoothed by an air knife 17 arranged on the side of the breast roll 15. The extra paint that is blown is collected in a catch pan 16. .

As shown in FIGS. 2 and 3, the air knives 17 for scraping off the excess paint are arranged in a pair on the left and right in this embodiment so as not to stop the line during maintenance and maintenance of the air outlet. A rotating mechanism (not shown) is used to rotate and select either the left or right air niff 17. Since the structure and operation of the air knife 17 are the same on the left and right, only one air knife 17 will be described. That is, as shown in FIG. 3, the air knife 17 is a hollow body having an isosceles triangular shape in cross section, which is composed of a back plate 18, knife holding members 19, 19, both side plates 20, 20, and lips 21, 21. An air outlet 22 is formed in the widthwise direction at the tip end side of 21, and pipes 23 for air supply are attached to both side plates. As shown in FIG. 4, the hollow portion 24 of the air knife 17 is provided with a reinforcing rib 25 with a predetermined span in the width direction to hold and reinforce the upper and lower lips 21, 21, and between the outlet 22 and the rib 25. A rectifying plate 26 is arranged in the width direction of the outlet 22.

The rectifying plate 26 is made of high-density polyethylene having a thickness of about 15 mm and has a large number of through holes 27. The through hole 27 is a step diffuser type including two holes 27a and 27b having different diameters. As shown in FIG. 5, the diameter of the hole 27a on the rib 25 side is larger than the diameter of the hole 27b on the outlet 22 side. Has become.

The operation of the air knife 17 of the present embodiment having the above structure will be described. The base paper P coated with the coating material by the applicator roll 12 arranged at the lower stage of the transfer roll 11 runs through the metering roll 14 and the breast roll 15, and is moved by the air knife 17 arranged at a position facing the brest roll 15. The excess paint is removed and the surface is smoothed.

That is, the air knife 17 is constantly supplied with air from the pipes 23, 23 attached to the side plates 20, 20, and this air passes from the hollow portion 24 through the through hole 27 of the current plate 26, It becomes a laminar flow of the same pressure and blows out from the outlet 22 in the direction orthogonal to the coated surface of the processed base paper P as shown by the arrow in Fig. 2, and the paint applied to the base paper P is kept constant with a constant wind pressure. The paint is sprayed evenly to the thickness of the other and the excess paint is blown off. The paint that has been blown off is collected by the catch pan 16 provided on the lower surface of the air knife 17.

Since the air knife of the present embodiment has the above-mentioned configuration, even if turbulent flow occurs in the air supplied to the hollow portion of the air knife, the air knife passes through the through hole of the straightening vane and is directed in the width direction of the outlet. A laminar flow of constant pressure is blown out from the whole, air is blown out, and there is no coating unevenness on the coating surface.

Although the current plate 26 is made of high-density polyethylene in the above embodiment, it is not limited to this and may be made of other synthetic resin such as epoxy resin or phenol resin. The through hole 27 to be provided may not be a step diffuser type but may be a through hole in which the diameter of the hole is gradually reduced.

Further, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications and design changes can be made without departing from the spirit of the invention.

[0013]

[Effect of device]

 Since the present invention has the above-mentioned configuration, it has the following effects. Since a rectifying plate with a large number of holes formed in the air outlet is installed, the air supplied to the inside of the air knife passes through the holes in the rectifier plate, so that it is uniform in the width direction of the outlet. It becomes a laminar flow of pressure and is jetted toward the coated surface, and can be evenly spread over the entire width direction of the coated surface. Therefore, uneven coating does not occur on the coated surface. The structure is simple and the number of parts is small, so it can be applied to existing air knives and is extremely practical.

[Brief description of drawings]

FIG. 1 is a schematic side view of a coating machine equipped with an air knife according to a first embodiment of the present invention.

FIG. 2 is a plan view showing an air knife of the present invention.

FIG. 3 is a sectional view of the air knife of the present invention.

FIG. 4 is a partially cutaway perspective view showing the inside of the air knife.

FIG. 5 is a partially cutaway perspective view showing a current plate.

FIG. 6 is a view showing a conventional air knife.

[Explanation of symbols]

 10 Coating Machine 11 Transfer Roll 12 Applicator Roll 13 Color Pan 14 Metalling Roll 15 Breast Roll 16 Catch Pan 17 Air Knife 18 Back Plate 19 Knife Holding Member 20 Side Plate 21 Lip 22 Air Blowout 23 Pipe 24 Hollow Part 25 Rib 26 Rectifier 27 Through hole

Claims (2)

[Scope of utility model registration request] 1. An air knife for a papermaking coating machine, wherein the coating material applied to the paper surface by an applicator roll is adjusted to a predetermined coating amount by an air knife equipped with an air outlet, the inside of the air outlet of the air knife. An air knife for a paper coating machine, characterized in that a flow straightening plate having a large number of through-holes opening toward the outlet is disposed on the air knife. 2. The air knife for a paper coating machine according to claim 1, wherein the through hole provided in the straightening vane is a through hole having two different diameters and having a step.