JPS62268642A - Double facer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a double facer for manufacturing double-sided corrugated board. (Prior Art) FIG. 6 shows a schematic diagram of a conventional double facer. In the figure, a single-sided corrugated pole 1 made by a single facer (not shown) in the previous step is entered into a double facer 5 after a starch paste 13 is applied to the top of the corrugated corrugated paper by a glue machine 14.

On the other hand, the liner 2 is preheated by the preheater 4 and enters the double facer 5 while merging with the single-sided corrugated board 1 at the entrance. Single-sided cardboard 1 and liner 2 in double facer 5
In the heating part 6, the material is held between the lower surface of an endless belt 8 driven by a roll 12 and a heating box 9, and is simultaneously transferred while being pressurized by a plurality of weight rolls 10 arranged in parallel within the belt 8. . When the single-sided corrugated board 1 and the liner 2 pass through this heating part 6, they are heated by the heating box 9, which has high-temperature steam inside, and the starch paste gelatinizes, forming the corrugated top of the wavy core of the single-sided corrugated board 1. The liner 2 is adhered to form a double-sided corrugated board 3. This double-sided corrugated pole 3 is held between the belt 8 and another belt 11 in the subsequent cooling part 7,
It is sent to the next process while being pressurized by weight rolls 10.

In the conventional double facer with the above configuration,
It had the following drawbacks.

(The amount of heat required to gelatinize the 11H paste depends on heat transfer from the heating box 9 through the liner 2, but because the thermal conductivity of the liner 2 is low, the temperature of the liner 2 itself must be set above the gelatinization temperature. According to thermal calculations, about 70% of the supplied steam power is used to simply heat up the paper, which is not used for direct bonding, which is extremely uneconomical.

(2) The time required to raise the temperature of the liner is unavoidably necessary, and there is a limit to how fast the device can be increased by that amount.

(3) In addition, in the conventional heating method as described above, heat transfer from the heating box to the liner is thought to be uniform over the entire surface, but due to heat radiation from the edges, it spreads across the width of the sheet, and the central portion High (low temperature distribution occurs at the edges, resulting in uneven lamination, wrinkles, warping, etc. of the sheet).

(Problems to be Solved by the Invention) As described above, the heating part of the conventional double facer relies on conduction heating via the liner as the heating means required for gelatinization, so the heating efficiency is low. This makes it impossible to increase the speed, and furthermore, even though there is heat dissipation at the sheet edges, the heating is uniform over the entire surface of the sheet, resulting in a temperature distribution where the center is high and the ends are low when viewed in the width direction. This also causes uneven lamination, wrinkles, warping, etc. of the sheet.

The present invention has been developed to solve these problems.
It is an object of the present invention to provide a double facer that can efficiently heat a structural part by dielectric heating and can evenly heat the entire surface of a sheet.

(Means for Solving the Problems) Therefore, the present invention provides a double facer in which a double-sided corrugated pole is formed by overlapping and laminating a single-sided corrugated pole and a liner that are glued to the top of the corrugated part in advance. and on at least one side of the liner, dielectric heating devices are installed in a plurality of zones in the width direction of the corrugated board, and each dielectric heating device operates independently, and this is a solution to the above problem. It is something.

(Function) According to dielectric heating, it is possible to concentrate heating directly on the structural parts, thereby increasing thermal efficiency and leading to faster operation. At the same time, since the amount of dielectric heating can be adjusted in the width direction of the sheet, it is possible to heat the sheet at a uniform temperature over the entire width of the sheet.

As a result, uneven bonding, wrinkles, warping, etc. will not occur on the sheet.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows an outline of a double facer which is an embodiment to which the present invention is applied. In the illustrated example, the dielectric heating device is arranged as a grid electrode on one side of the sheet. That is,
The same dielectric heating device is used in the heating part 6 and the 6th part.
Instead of using the conventional heating box 9 and weight roll 10 shown in the figure, a grid electrode 15 with a plurality of electrodes arranged side by side is installed on the liner 2 side, and an insulating belt 16 is used instead of the conventional belt 8. It is installed.

An example of the arrangement of the grid electrodes 15 is shown in FIG.

FIG. 2 shows an example in which grid electrodes are arranged in three zones in the sheet width direction. Here, (+) pole and (-
) Several units of electrodes with a predetermined cross-sectional shape and length having alternating poles were installed at predetermined intervals in the flow direction of the corrugated sheet, and were supported by an insulator (not shown).
By applying a high frequency voltage between the ) pole and the grounded (-) pole, an electric field 17 as shown by the arrow in FIG. 3 is generated.

Due to dielectric heating caused by this electric field, inside the corrugated sheet
E2εtan δ・f (ε: relative dielectric constant, tan δ:
Heat is generated in proportion to the dielectric series (f: frequency, E: electric field strength), but the value of εtan δ is 20 to 30 times higher than the water in the glue and the electric field generated. This concentrates on the adhesive portion 18, allowing extremely efficient heating and drying.

It is also possible to arrange the grid electrodes 15 so as to sandwich the cardboard sheet between them, and this arrangement allows the application to a thick double-sided cardboard sheet 19 as shown in FIG. is (+) pole on one side,
The (-) pole is arranged in parallel with the other surface so that the electric field 17 flows from the (+) pole to the (-) pole as shown in FIG. In addition, to prevent different temperature distributions that occurred in the width direction, which was a problem in the past, several zones were created in the width direction of the sheet, and a dielectric heating device was installed independently in each zone, and at the same time, each of the above-mentioned This problem can be solved by adjusting the heat input to each bonding structure by controlling the output of the dielectric heating device for each zone.

In addition, in response to variations in sheet width, for example, as shown in FIG. 5, the electrode group 21 at the center can be rotated about the center of each electrode as the center of rotation 22, and at the same time, the electrode groups 20 at both ends of the sheet can be rotated. By having a structure in which the sheet 23 can slide in the paper width direction, it is possible to cope with changes in sheet width.

(Effects of the Invention) As described above in detail, according to the present invention, heat can be directly concentrated on the structure by installing a dielectric heating device, so that it is sufficient to supply only the amount of heat necessary for gelatinization. This allows for significant energy savings. Furthermore, the improved heating efficiency allows the machine to be made faster or more compact.

Furthermore, by making it possible to control the temperature in each zone, the temperature distribution in the width direction, which was a problem in the past, can be made uniform, thereby suppressing the occurrence of wrinkles, uneven lamination, warping, etc. in the corrugated cardboard sheet. and you can get good quality products. By making it possible to control the temperature in each zone over the sheet width, it has become possible to easily respond to changes in the sheet width.

[Brief explanation of drawings]

FIG. 1 is a schematic side sectional view of a double facer showing an embodiment of the present invention, FIG. 2 is a partial perspective view showing an example of grid electrode arrangement applied to the present invention, and FIG. FIG. 4 is a diagram showing an example of electrode arrangement and the direction of the electric field when applied to the production of double-sided corrugated cardboard sheets of the present invention, and FIG. The figure shows an example of electrode arrangement according to paper width variations, and FIG. 6 is a schematic side sectional view of a conventional double facer. Explanation of main parts of the figure 1 - Single-sided corrugated board 2... Liner 3 - Double-sided corrugated pole (sheet) 5... Double facer 6 - Heating part 14 - Glue machine 15 - Grid electrode 16 - Insulating belt 17 - -Electrode field 20.21.23--Electrode group

Claims (1)

[Claims] In a double facer that forms a double-sided corrugated board by overlapping and laminating a single-sided corrugated board and a liner that have been glued to the top of the corrugated board in advance, a plurality of zones are divided in the width direction of the corrugated board on at least one surface of the single-sided corrugated board and the liner. A double facer characterized by installing dielectric heating devices and each dielectric heating device operating independently.