JPH0740560Y2 - Dryer canvas for papermaking - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a dryer canvas for papermaking, which can make the moisture content of a wet paper web uniform.

(Prior Art) When drying paper in a multi-cylinder dryer of a paper machine, ventilation conditions are poorer in the central part of the paper than in the side edges, and the drying is delayed. Suggestions have been made.
For example, in Japanese Patent Laid-Open No. 62-41394, as a means suitable for a multi-structure papermaking dryer canvas having a core warp thread, a ridge in the weft direction is formed on at least one side edge portion by a warp warp ridge. Is disclosed. In other words, the ridge of the dryer canvas is used as the paper contact surface side, and the wet cylinder is pressed against the heating cylinder for drying, so that the entire central portion of the slow-drying wet paper is in strong contact with the heating cylinder. The fast drying side edge is partially heated by contacting the heating cylinder only with the linear or strip-shaped portion contacting the ridge of the dryer canvas.
The drying speed is made uniform over the entire width. Further, instead of forming the ridges, it has also been performed for a long time to balance the drying speed by closing the weave of the side edge portion with a resin processing and reducing the air permeability of this side edge portion. .

(Problems to be solved by the invention) However, in the conventional dryer canvas, the float of the weft yarn with respect to the core warp yarn is increased along the linear or strip-shaped portion of the side edge portion, and the warp yarn is floated on the weft yarn. Since the ridge was formed and the length of the ridge was formed to fill the width of the side edge, only the part in contact with the top of the ridge is heated strongly and is excessively dried, but other than the ridge Since the portion (1) is heated slowly, it is apt to be insufficiently dried, resulting in uneven drying. In addition, in a dryer canvas where the side edges are made air-permeable by resin processing, the desired effect is obtained when a canvas with low air permeability is used to avoid the occurrence of fluttering, as in high-speed papermaking such as newspaper. I couldn't get it.

This invention proposes a method for drying between the central part and the side edge by interspersing protrusions or depressions shorter than this, instead of the ridge that extends over the width of the side edge, on the side edge. It is intended to provide a dryer canvas which makes the speed uniform and enables uniform drying over the entire width.

(Means for Solving the Problems) In a dryer dryer for papermaking having a multiple structure in which one or more weft yarns are arranged above and below the core warp yarn, the number of layers of the weft yarn floating on the core warp yarn at least at one side edge portion is determined. The protrusions or indentations, which are partially different from the central portion other than the side edge portions and have different heights of the warp threads floating on the weft thread, are intermittently provided in both the width direction and the length direction of the side edge portions. Form. The preferable width of the side edge portion is 1 to 20% of the entire width of the dryer canvas, and can be appropriately set depending on the drying condition of the wet paper web.

(Operation) When the wet paper is pressed against the heating cylinder using the canvas of the present invention and dried, the central portion of the wet paper is pressed against the surface of the heating cylinder by the central portion of the dryer canvas as in the conventional case. The entire surface of the part is heated. On the other hand, since the side edge portion of the dryer canvas is provided with a protrusion or a recess, the portion in contact with the protrusion is in contact with the heating cylinder with a slightly stronger pressure than its surroundings, while drying is promoted, The drying is delayed in the surrounding area, and the average drying speed of the entire side edge portion is the same as that of the central portion. In addition, the portion in contact with the recess is delayed in drying by contacting the heating cylinder with a weaker pressure than the surrounding area, but since the surrounding area is heated by contacting the heating cylinder with the same pressure as the central part, the side edge The average drying speed of the whole part is similar to that of the central part.

(Example) In FIG. 1, 1 is a dryer canvas, 1A is a central portion thereof, 1B is a side edge portion thereof, and the side edge portion 1B has a rectangular flat portion 2 of the same structure as the central portion 1A and this. The lower rectangular recesses 3 are alternately arranged in the length direction and the width direction to form a checkered pattern. Then, the central part
As shown in FIG. 2, 1A is composed of a core warp thread 11, a warp thread 12 and a weft thread 13, two weft threads 13 are arranged above the core warp thread 11, and one weft thread 13 is below the core warp thread 11. The warp yarns 12 arranged are alternately up and down six by six with respect to the three-layer weft yarns 13 to form a 1/3 twill structure with the uppermost weft yarns 13. Then, in the side edge portion 1B, as shown in FIG. 3, between the flat portions 2 and 2 having the same structure as the central portion 1A,
An indentation 3 is formed by sinking all three layers of weft thread 13 under the core warp thread 11.

The embodiment of FIG. 4 is an example in which the projecting portion 5 is formed on the side edge portion 1B, and the side edge portion 1B is divided into four strip-shaped areas 6a, 6b, 6c, 6d. The strips 6a, 6c are formed only by the flat portion 2 having the same structure as the central portion 1A, and the second and fourth strips are formed by the alternating arrangement of the flat portions 2 and the protrusions 5 protruding from the flat portions 2. There is. Thus, the central portion 1A and the first and third strip-shaped sections 6a, 6c are woven into the tissue of FIG. 2, and the second and fourth strip-shaped sections 6b, 6d are as shown in FIG. Then, all three layers of weft yarn 13 between the flat portions 2 and 2 are floated on the core warp yarn 11 to form the protrusion 5.

(Effects of the Invention) In the present invention, in a dryer dryer for papermaking having a multi-layered structure having a core warp thread, the number of layers of the weft thread floating on the core warp thread is partially different at least at one side edge portion thereof, so that the center It is formed by intermittently forming protrusions or dents that have different heights compared to the parts in both the width direction and the length direction, so the central part with poor ventilation conditions is heated relatively strongly and ventilation conditions are good. The side edges are heated relatively weakly, so that the dryness is evened out over the entire width. And since the above-mentioned protrusions or depressions are formed by the woven fabric structure at the time of weaving, there is no need to perform special processing after weaving, and they do not disappear due to use, and the performance may deteriorate during use. Absent. In addition, it is not necessary to change the warp yarn density and the weft yarn density between the central portion and the side edge portions, and therefore, premature breakage and poor running due to imbalance of tension and rigidity do not occur. Moreover, since the protrusions or depressions are provided intermittently, the portions that strongly contact and weakly contact the heating cylinder are subdivided as compared with the case where the ridge is formed to fill the width of the side edge portion, and thus the above strongly contact. Heat is smoothly transferred between the portions and the weakly contacting portions, the moisture content of the wet paper is easily averaged, and unevenness in drying of the wet paper is eliminated.

[Brief description of drawings]

1 is a plan view of a side edge portion of an embodiment of the present invention, FIG. 2 is a vertical sectional view of a central portion of FIG. 1, FIG. 3 is a sectional view of a side edge portion of FIG. 1, and FIG. FIG. 5 is a plan view of another embodiment, and FIG. 5 is a fourth view.
It is a longitudinal cross-sectional view of the side edge portion of the figure. 1: Dryer canvas, 1A: central part, 1B: side edge part, 2: flat part, 3: hollow, 5: protrusion, 11: core warp thread, 12: warp thread, 13:
Weft

Claims (1)

[Scope of utility model registration request] 1. In a dryer dryer for papermaking having a multiple structure in which one or more weft yarns are arranged above and below the core warp yarn, the number of layers of the weft yarn floating on the core warp yarn at least at one side edge portion is defined as the side edge portion. Other than the central portion other than the central portion, the protrusions or depressions having different heights of the warp threads floating on the weft thread are formed intermittently in both the width direction and the length direction of the side edge portion. A unique dryer canvas for papermaking.