JPH11140786A - Apparatus for removing water content of press part in papermaking machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve water content-removing performance in removing water content of wet paper in a press part of a papermaking machine. SOLUTION: In a water content-removing apparatus 1 of a press part of a papermaking machine, a device for heating, wet paper 1 interposed in a nipping part 11 for press nip is provided and a vacuum chamber 52 hermetically sealing the neighborhood of the wet paper 1 heated by the device is formed around the nipping part 11 for press nip and a vacuum device 50 for reducing the pressure in the vacuum chamber 52 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for removing water from a press part of a paper machine.

[0002]

2. Description of the Related Art A press part of a conventional paper machine is provided with a nip portion composed of a press roll and a press roll, or a nip portion composed of a press roll and a press shoe. It applies water pressure by applying press nip pressure.

[0003]

However, the prior art has the following problems. The water squeezing performance of the conventional water squeezing device is not sufficient, and further improvement of the water squeezing performance is desired.

[0004] In a conventional linear water press, in which the press nip pressure at the sandwiching portion is increased, a high linear pressure type press greatly increases the paper density, and the equipment requires pressure-resistant, high-strength, and high power, resulting in high cost.

[0005] It is an object of the present invention to improve the performance of removing moisture from wet paper in a press part of a paper machine.

[0006]

According to the present invention, there is provided a press machine for applying water to a wet paper web by applying a press nip pressure.
In the water removal device of the press part of the paper machine provided with the nip pinch, a heating device for heating the wet paper sandwiched between the press nip pinch is provided, and the heating is performed around the press nip pinch. A vacuum decompression chamber in which the periphery of the wet paper heated by the apparatus is sealed is formed, and a vacuum decompression device for depressurizing the vacuum decompression chamber is provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the heating device further heats a press roll constituting a press nip holding portion,
A heating device is provided in which a wet paper is brought into contact with the heating surface of the press roll to heat it, and a high contact pressure applying device for increasing the contact pressure of the wet paper to the heating surface of the press roll is provided. It is.

[0008]

According to the first aspect of the present invention, there is provided the following operation. By heating the wet paper with a warming device, the viscosity of the water contained in the wet paper is reduced, the fluidity of the water when the press nip pressure is applied is increased, and the press squeezing at the sandwiching portion is performed. Performance can be improved.

[0009] By evacuation of the environment of the heated wet paper with a vacuum decompression device, the evaporation of moisture contained in the wet paper is promoted, and the moisture content of the wet paper can be reduced.

According to the second aspect of the present invention, the following operations are provided. By the high contact pressure imparting device, by increasing the contact pressure between the wet paper and the press roll surface, the heat transfer coefficient from the heated roll surface to the wet paper can be promoted, and the above-described press water squeezing performance is improved. It can contribute to improvement.

Therefore, according to the first and second aspects of the present invention, as described above, the water content at the press outlet of the wet paper web can be reduced as compared with the conventional water squeezing device, and the water removal performance can be further improved. Also, while reducing the press nip pressure of the sandwiching part compared to the conventional water squeezing device, the same or more water squeezing amount can be obtained by the high nip pressure in the conventional water squeezing device, so that the paper density can be reduced. The rise can be reduced, and the cost can be reduced because the equipment does not require high pressure, high strength and high power.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing an apparatus for removing water from a press part according to the present invention. The water removing device 10
A pair of press rolls 11 forming a press-nip sandwich 11 for applying water to the wet paper 1 by applying a press-nip pressure
A, 11B, and a felt feeding device 20 and an inner fabric feeding device 30 for feeding the wet paper web 1 to the sandwiching portion 11.

The felt feeding device 20 includes an entrance touch roll 12A around which the felt 21 is wound, an exit touch roll 12B, and felt rolls 22A to 22E.
The inner fabric feeding device 30 is provided with an entrance touch roll 1 around which the inner fabric 31 is wound.
2A, exit touch roll 12B, felt roll 22
A, 22B, and fabric rolls 32A to 32C. Thereby, the wet paper web 1 is put on the felt 21 which is backed up by the inner fabric 31 on the exit side of the paper roll 13A, and passes through the felt roll 22A from the entrance touch roll 12A to around the press roll 11A. The paper is wound around, separated from the felt 21 at the exit touch roll 12B, further separated from the press roll 11A, passed from the paper roll 13B to the canvas 15 around the canvas roll 14, and sent out toward the dry part.

The water removing device 10 is provided with a press roll 1
A release agent shower 16 and a doctor 17 are provided at positions where the wet paper web 1 is not wound around 1A.

However, the water removing apparatus 10 is provided with the following (A) to (C) in order to improve the water removing performance. (A) Heating device By heating the wet paper web 1 sandwiched between the sandwiching portions 11, the viscosity of water contained in the wet paper web 1 is reduced, and when the press nip pressure by the sandwiching portions 11 acts. It increases the fluidity of water and improves the press squeezing performance. The following methods (a) to (d) can be adopted as a method for heating the wet paper 1.

(A) The wet paper web 1 before reaching the sandwiching portion 11 is heated with high-temperature air or high-temperature steam. Specifically, the upper surface of the wet paper web 1 is covered by the heating box 41 of the heating device 40 provided on the entrance side of the sandwiching portion 11, and the lower surface of the wet paper web 1 is covered by the suction box 42. The high-temperature air or high-temperature steam blown from 41 is passed through the wet paper web 1 and sucked into the suction box 42 to heat the wet paper web 1.

(B) The wet paper web 1 before reaching the sandwiching portion 11 is heated by infrared rays. Specifically, an infrared heating device is provided at the position of the heating device 40.

(C) The wet paper web 1 before reaching the sandwiching portion 11 is dielectrically heated. Specifically, a dielectric heating device is provided at the position of the heating device 40.

(D) The press roll 11A is heated,
The wet paper web 1 is brought into contact with the heating surface of the press roll 11A to heat it. As the method of heating the press roll 11A of (d), the following methods can be adopted.

The inside of the press roll 11A is made to have a hollow structure, and high-temperature steam is put in the inside and the drain is discharged, so that the sensible heat and latent heat of the steam are used, or high-temperature air obtained by gas combustion is used. Then, the inside of the roll is heated to increase the surface temperature of the press roll 11A.

The inside of the press roll 11A has a hollow structure, and oil heated outside the roll is circulated inside the press roll 11, thereby heating the inside of the roll and increasing the surface temperature of the press roll 11A.

The surface of the press roll 11A is dielectrically heated by a dielectric heating device 43 provided along the outer periphery of the press roll 11A to increase the roll surface temperature.

When the surface of the press roll 11A is heated in the above (d), the paper of the wet paper 1 is
Therefore, the wet paper web peeling technique which can easily peel the wet paper web 1 from the surface of the press roll 11A at the exit of the press nip of the sandwiching portion 11 is used together.

(B) Vacuum depressurizing device The area around the wet paper 1 heated by the heating device of the vacuum decompressor (A) is decompressed in vacuum to promote the evaporation of the moisture contained in the wet paper 1, and That reduce the water content of The following methods (a) and (b) can be used as a method for decompressing the surroundings of the wet paper 1.

(A) Around the sandwiching portion 11, a vacuum decompression chamber 52 is formed in which the periphery of the wet paper web 1 heated by the heating device 40 is sealed by a vacuum decompression box 51 of a vacuum decompression device 50. The vacuum decompression chamber 52 is evacuated by an external vacuum pump to reduce the pressure.

The vacuum pressure reducing system of the vacuum pressure reducing device 50 includes water evaporated from the wet paper 1, water squeezing from the pinch portion 11,
Since moisture accompanying peripheral equipment flows in, it is necessary to remove moisture to a level that does not adversely affect the vacuum device (vacuum pump).

(B) Sealing area around the wet paper The installation range of the vacuum decompression box 51 is such that the wet paper 1 is heated and the wet paper 1 travels while accompanying the felt 21 to seal the surroundings. Where it can be planned.

From the press nip outlet of the pinch portion 11,
Outlet touch roll 12 for separating wet paper web 1 from felt 21
The range up to B is sealed by the outlet vacuum decompression box 51B and reduced in pressure.

By removing the felt moisture up to the press nip entrance of the sandwiching portion 11, the water squeezing at the press nip point of the sandwiching portion 11 can be improved. The area from the roll 12A to the press nip inlet is also sealed by the inlet vacuum decompression box 51A, and the pressure is reduced.
Therefore, in this range, the following two functions are covered.

(1) Promotion of moisture evaporation of wet paper by vacuum decompression (2) Improvement of water squeezing at press nip point by removal of felt moisture In FIG. 1, 52A and 52B are vacuum suction ports connected to a vacuum pump. , 53A and 53B are seal portions, and 54 is a ball. The inlet vacuum decompression box 51A and the outlet vacuum decompression box 51B may be continuous below the press roll 11B to form a single vacuum decompression box 51.

(C) High Contact Pressure Apparatus The contact pressure of the wet paper web 1 on the surface of the press roll 11A heated by the heating device of (A) is increased, and the heat from the heated surface of the press roll 11A to the wet paper web 1 is increased. What facilitates communication. Wet paper 1
The following (a) to (c) can be adopted as a method for increasing the contact pressure between the press roll 11A and the press roll 11A.

(A) Improvement of Contact Pressure Due to Felt Tension In the moisture removing device 10, since the wet paper web 1 and the felt 21 travel together, the felt 21 contacts the roll surface of the press roll 11A as long as possible. At this time, the felt 21 travels along the surface of the press roll 11A.
It acts as a contact pressure on the roll surface by the felt 21. The felt 21 is stretched within the range of the tensile strength by using any one of the felt rolls 22A to 22E as a stretch roll, so that the wet paper web 1 is pressed against the surface of the heating roll 11A to increase the contact pressure therebetween.

(B) Improvement of Contact Pressure by Inner Fabric Tension By using the inner fabric 31 together, the contact pressure between the wet paper web 1 and the surface of the press roll 11A is increased. In order to further increase the contact pressure between the wet paper web 1 and the surface of the press roll 11A, the inner fabric 31 is also run in a range where the wet web web 1 and the felt 21 run together. Regarding the inner fabric 31, apart from the felt 21,
Either of the fabric rolls 32A to 32C is used as a stretch roll and independent tension is applied within the range of the tensile strength. Since the contact pressure between the wet paper 1 and the roll surface due to the tension of the inner fabric 31 is independent of the contact pressure due to the felt 21, the contact pressure between the wet paper 1 and the roll surface is a value obtained by adding both.

(C) Contact Pressure Due to Press Nip Pressure The press roll 11A and the press roll 11B of the sandwiching portion 11
At the press nip point where the wet paper web 1 is pressed, the linear pressure most effectively brings the wet paper web 1 into contact with the surface of the press roll 11A.

The moisture removing device 10 is configured to spray hot paper or hot steam onto the wet paper web 1 at a position where the canvas 15 sends out the wet paper web 1 to contribute to drying of the wet paper web 1 in the dryer part. A heating box 61 and a suction box 62 for bringing the wet paper web 1 into close contact with the canvas 15 are provided. The heating box 61 and the suction box 62 are opposed to each other.

According to the present embodiment, the following operations are provided. By heating the wet paper web 1 by heating the press roll 11A or the heating device 40, the viscosity of the water contained in the wet paper web is reduced, and the fluidity of the water when the press nip pressure acts is reduced. It is possible to improve the water squeezing performance in the sandwiching portion 11 by increasing the height.

Vacuum decompression of the heated environment of the wet paper web 1 by the vacuum decompression device 50 promotes evaporation of water contained in the wet paper web 1 and lowers the moisture content of the wet paper web 1. Can

By increasing the contact pressure between the wet paper web 1 and the press roll surface by the high contact pressure applying device, the heat transfer rate from the heated roll surface to the wet paper web 1 can be promoted. It can contribute to the improvement of press water squeezing performance.

Accordingly, from the above, the water content at the press outlet of the wet paper web 1 can be reduced as compared with the conventional water squeezing device, and the water removal performance can be further improved. Further, while reducing the press nip pressure of the sandwiching portion 11 as compared with the conventional water squeezing device, the water squeezing amount equal to or higher than the high nip pressure in the conventional water squeezing device can be obtained. The cost can be reduced by eliminating the need for pressure-resistant, high-strength, high-power equipment.

According to the present invention, the surface properties of the paper at the press outlet can be improved.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific structure of the present invention is not limited to the embodiments, and the design may be changed without departing from the scope of the present invention. The present invention is also included in the present invention. For example, the press nip clip portion of the present invention may be formed by a combination of a press roll and a press shoe.

[0042]

As described above, according to the present invention, it is possible to improve water squeezing performance and to further remove moisture by evaporation when removing moisture from wet paper in a press part of a paper machine.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a water removal device for a press part according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wet paper 10 Water removal device 11 Nipping part 11A, 11B Press roll 40 Heating device 50 Vacuum decompression device 52 Vacuum decompression room

Claims (2)

[Claims] 1. A water removing device for a press part of a paper machine having a press nip pinch for applying water to a wet paper by applying a press nip pressure, wherein the wet paper sandwiched by the press nip pinch is removed. A heating device for heating is provided, and a vacuum decompression chamber is formed around the press-nip pinch, in which the periphery of the wet paper heated by the heating device is sealed, and the vacuum decompression chamber is depressurized. A water removing device for a press part of a paper machine, comprising a device. 2. The heating device according to claim 1, wherein the heating device heats a press roll forming a press-nip holding portion, and brings a wet paper into contact with a heating surface of the press roll to heat the press roll. The water removing device for a press part of a paper machine according to claim 1, further comprising a high contact pressure applying device for increasing a contact pressure of the wet paper to a heating surface of the press roll.