JPS6052697A - Twin wire former of papermaking machine - 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] In a conventional paper machine wire section called a four-dryer, a single wire runs horizontally and is dehydrated downward by foils arranged on the underside of the wire to form a paper layer. However, the resulting paper had the disadvantage that the fine fibers near the wire surface were washed away and decreased.

With twin wires, water is dehydrated on both sides, so the distribution of fine fibers in the thickness direction of the paper can be made more symmetrical. When dewatering is performed using a fixed dewatering member similar to a foil (usually called a shoe), a pulse pressure with high dehydration pressure is applied to the raw material liquid as it passes before and after the shoe, so the sharp movement of the water causes dehydration. However, there was a drawback that the yield of fine microfibers was lower than that of the Fourdrinier method.

The present invention was proposed in order to eliminate the above-mentioned conventional drawbacks, and it is possible to obtain a paper with better texture than paper made with Fourdrinier and less difference between the front and back sides, and also to reduce the yield of fine fibers in the twin wire section. In order to obtain a twin-wire former for a paper machine that improves the performance and allows easy operation adjustment, the twin-wire former is of a type in which a twin-wire dewatering section is connected after a four-linear dewatering section. Place the vacuum foil box appropriately, bring the wire running from above close to the horizontally running Ford Linear wire, sandwich the raw material liquid between the two wires, and place the LJ roll installed inside the Ford Linear loop. The set of wires is run downward at the "circumference", and this roll section dewaters the upper wire side, and then the set of wires is rolled back in a horizontal direction to the wire side of the Fourdrinier. A suction box was placed below the set of wires that had been dehydrated and returned to a horizontal position, and the wires of 1111 were allowed to hang out on the circumference of the couch roll, and the paper layer was pulled toward the Fourdrinier wire side using vacuum pressure with the couch roll. , ” aims to provide a twin-wire former for a paper machine, which is characterized in that the two-part wires are separated.

Embodiments of the present invention will be described below with reference to the drawings. The drawings show one embodiment of the present invention. In the figure, head box 1
In front of the spout, there is a Fordrinier dehydration section ■, followed by a twin wire dehydration section ■. Forming boards 3 and foils 4 are lined up in the loop of the lower wire 2 running horizontally in the Fordrineer dewatering section I, and dewatering is carried out using vacuum pressure and foils in the last and middle parts of the Fourdorinier dewatering section I. Place the vacuum foil box 5 appropriately, approach the second upper wires 4 and 6 from the negative direction, sandwich the raw material with the wire nip, and make a set of wire runs on the circumference of the roll 7 placed within the loop of the lower wire 2. (twin wire run) is bent downward to drain water to the upper wire side, and the water is received at the socket 8.

Next, a roll 9 is provided to return the twin wire run to a horizontal direction, and a roll dewaters the lower wire 2 side. A suction box 1o is provided below this horizontal twin wire run to dewater the water using vacuum pressure, and then a couch roll is provided. 11 is provided and the two wires are let down on this roll, and the upper wire 6 is released while the paper layer is drawn toward the wire 2 by the vacuum pressure of the couch roll 11.

The surface of the roll 7.9 used for dewatering may be smooth, but it may also be an open roll with grooves cut into the surface and a coarse wire wound around the surface. Also roll 1
The position of the wire 2 can be adjusted vertically by an adjustment mechanism (not shown), thereby making it possible to adjust the nip point of the upper wire 6 on the roll 7.

Next, the operation will be explained. The raw material liquid ejected from the head box 1 is dehydrated in the same manner as in the conventional Fourdrinier dehydration section. Here, since the amount of water removed and the phenomenon of the raw material liquid jumping up on the wire differ depending on the well-known foil angle, adjustments such as paper formation can be made according to the paper type by combining and arranging multiple foils with different angles. . In the Fordrinier, the two surfaces of the raw material liquid are free surfaces, so
The dewatering pressure applied to the raw material liquid as it passes before and after the foil is gentle, and the yield of fine fibers in the Fourdrinier dewatering section is higher than that of the shoe type twin wire rammer.

In addition, the vacuum foil box 5 adjusts the appropriate concentration of the raw material liquid to enter the twin wire dehydration section (2) by adjusting the foil angle and vacuum pressure. Note that there may be a plurality of vacuum foil boxes. Here, the twin wire run is first bent downward, and water is dewatered toward the upper wire 6 side, so that a large amount of water can be dehydrated to the upper part. In this case, since the initial dewatering section of the twin wire is dehydrated with rolls, the dewatering pressure does not fluctuate.

The moisture content of the paper layer entering the couch roll 11 by the suction box 10 is adjusted by changing the vacuum pressure, and
Form a dry line. In addition, suction box 1
There may be more than one 0.

Further, since the upper wire 6 is released on the couch roll 11, the release point is stabilized. At this time, the paper layer is pulled toward the lower wire 2 by vacuum pressure, so the paper layer does not follow the upper wire 6.

Since the present invention is structured as explained in detail below, the ttb ratio can be adjusted in the four-dried dewatering section, and the twin wire dewatering section increases the dewatering toward the upper wire side, thereby reducing the difference between the front and back sides of the paper. can be reduced.

In addition, the initial dewatering section in the twin wire dewatering section, which contains a large amount of water (I), can be used as a roll to improve the yield of fine fibers. Furthermore, all bends in the wire run are rolled.
Wire life can be extended and driving power can be reduced.

In addition, since a vacuum foil box was installed, the concentration of the raw material liquid entering the twin wire could be adjusted, making operation easier even when the freeness and paper type changed.Furthermore, the suction box 10 was installed in front of the couch roll, so the concentration of the raw material liquid entering the twin wire could be adjusted. It can increase the moisture content of the layer, operate at high speed and high basis weight,
Even when the dehydration load increases, the suction box
Second, it can be adjusted to create a dry line, making it easy to operate. In addition, while the couch roll draws the paper layer to the lower wire, the upper wire is separated from the roll circumference, which stabilizes the paper separation.

On the other hand, the foil box and suction box were brought to the bottom of the horizontal wire run.
It is easy to treat dehydrated water.

Furthermore, it is easy to replace the foil by changing its angle or by re-polishing the wire contact surface.

[Brief explanation of drawings]

The drawing is a system diagram of a twin wire dewatering section showing an embodiment of the present invention. Explanation of main parts of the diagram r - Ford linear dewatering section n - Twin wire dewatering section 1 - Head box 2 - Lower wire 3 - Forming board 4 - Foil 5 - Vacuum foil box 6 - Upper wire 7 - Roll (horizontal section (rear end roll) 8-Dehydration socket 10-Suction box 1l-=-Couch roll

Claims (1)

[Claims] In a twin-wire dewatering section in which a twin-wire dewatering section is connected after a Fordrineer dewatering section, foils and vacuum foil boxes are appropriately arranged within the loop of the lower wire running horizontally in the Fordrineer dewatering section, and the lower wire An upper wire is provided so as to approach the rear end roll of the horizontal part from above and sandwich the raw material liquid, and the same wire is overlapped on the circumference of the rear end roll, and the wire is directed downward. a dewatering tray "1" is provided on the upper wire side of the rear end roll part, and a horizontal part is provided following the downward running part of the set of stacked wires,
A suction box is provided within the loop of the lower wire in the horizontal section, and a couch roll is provided within the loop of the lower wire at the end of the horizontal section, and after passing through the couch roll, the one silk wire is separated into upper and lower parts and run. The twin wire former of the paper machine is characterized by