JPH0320519B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to research and testing of paper manufactured by a twin wire type paper machine in paper making and to process control of the paper making process. , a method for forming wet paper for handmade paper for testing on a twin wire type paper machine to obtain handmade paper having characteristic values similar to those of paper obtained by a twin wire type paper machine, and implementing the method This invention relates to a wet paper forming device for test handsheet paper for twin wire paper machines.

[Conventional technology]

Fourdrinier (wire) paper machines used for paper making are mainly of the four-wire type and the twin-wire type. Generally, the four-wire type is used for making high-quality paper, while the twin-wire type is used for making medium-quality papers such as newspaper. It is often applied to produce paper at high speed and in large quantities. In addition, when making paper, before operating the actual paper machine, test handsheet paper is created using a handsheet forming device, its characteristics are investigated, and the optimum conditions are found before actual production. Most of the time, paper machines are operated.

Conventional methods and devices for preparing handsheets for testing have been widely used in accordance with JIS P 8209 "Method for Preparing Handsheets for Pulp Testing" as shown in FIG. That is, the device consists of a cylindrical container 8 and a grid plate 9 on which a wire mesh is placed at the bottom of the container.
It consists of a funnel 10, a drain pipe 11, a water receiver 112, etc., and a certain amount of paper stock solution (diluted suspension) is put into a cylindrical container 8, stirred with a perforated plate stirrer, drained, and placed on a wire mesh as wet paper. This was then sequentially coached, pressed, and dried to obtain handmade paper.

[Problem to be solved by the invention]

In the conventional method and apparatus for making such handsheet paper for testing, the dehydration direction is only one downward direction. However, the characteristics of the paper obtained using a twin-wire paper machine, in which paper stock liquid is sandwiched between two wires and dehydrated in both directions to form a paper layer, are similar to those of the paper obtained. There was a problem that there were differences in characteristics. In other words, the paper produced by a twin-wire paper machine has smaller differences in fine fibers and filler distribution between the two sides than the paper produced by a four-wire paper machine, but it also has weaker interlaminar strength. Therefore, when paper is produced using a twin-wire type paper machine, there is a problem in that conventional hand-made paper forming methods and devices are often not applicable.

Therefore, research into manufacturing new paper products using twin-wire paper machines, which have been developed in recent years mainly for the purpose of high-speed, mass production, and changes and settings of paper-making process conditions must be carried out using actual production machines. This made it difficult to research, develop, test, and manufacture paper using twin-wire paper machines. Therefore, there has been a strong desire to develop a method and apparatus that can produce handmade paper in a laboratory or testing laboratory that is similar in quality to paper produced by a twin-wire paper machine and has properties that closely correspond to those produced by twin-wire paper machines.

Therefore, the present invention aims to improve the various properties of paper obtained by a twin-wire paper machine, especially its characteristics such as interlaminar strength, fine fibers, and difference in filler distribution between the front and back sides, which can be obtained by an actual twin-wire paper machine. An object of the present invention is to provide a method and apparatus for forming a wet paper for testing handmade paper for a twin wire type paper machine, which allows handmade paper that approximates and corresponds well to the above to be obtained at a laboratory level.

[Means to solve the problem]

The inventors of the present invention have focused on the possibility of achieving the above object by using a method and device similar to the papermaking principle and means of a twin-wire paper machine, and have conducted various studies. A box-shaped upper dewatering tray with a paper screen attached to the lower end is placed in the upper opening of a cylindrical stock tank having an opening, and a box-shaped upper dewatering tray with a paper screen attached to the upper end is placed in the lower opening of the paper stock tank. At least one of the lower trays for dewatering is attached, and at least one of the trays is movable up and down along the inner wall of the paper stock tank, and a suction device is connected to each of the dewatering trays via a hose. A certain amount of paper stock liquid is injected into the stock tank and stirred so that the liquid level is at a predetermined position above the paper screen at the upper end of the lower dehydration tray, and then the paper stock liquid is placed above the paper screen on the upper dehydration tray. If the upper and lower paper screens are brought close to each other while the paper stock solution is suctioned and dehydrated from above and below alternately or simultaneously while the paper stock is buried in the paper, and a wet paper is formed between the upper and lower paper screens, the obtained wet paper can be We found that the handmade paper obtained by sequentially coating, pressing, and drying in the same manner as the above method approximates and corresponds well to the various properties of paper obtained using a twin-wire paper machine, thereby solving the above problem. This solved the problem.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method and apparatus for forming wet paper for test handsheet paper for a twin wire paper machine according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a front view showing, in cross section, the main parts of a wet paper web forming apparatus for test handsheet paper of a twin wire type paper machine according to the present invention.

In the drawing, 1 indicates an upper opening 1a and a lower opening 1b.
If this paper stock tank 1 is made of a transparent material such as acrylic resin at least in part from top to bottom, the state of the stock liquid inside can be seen through. It is preferable. 2 is a box-shaped upper dewatering tray that is attached to the upper opening 1a of the paper stock tank 1 and has a paper screen 2a attached to the lower end; 3 is attached to the lower opening 1b of the paper stock tank 1 and has the upper end. This is a box-shaped lower dewatering tray to which a paper screen 3a is attached. This paper net 2a and the upper dehydration tray 2,
It is preferable that the paper screen 3a and the lower dewatering tray 3 are each detachable so that they can be easily replaced with bronze wire, plastic wire, etc. in accordance with the actual wire of the paper machine. Reference numeral 4 denotes a moving mechanism for vertically moving the upper dewatering tray 2 or the lower dewatering tray 3 (upper dewatering tray 2 in the illustrated embodiment) along the inner wall of the stock tank 1, and has the following configuration. ing. That is, the piston rod 4aa of the cylinder 4a is connected to the coupling 4.
It is connected to the upper dehydration tray 2 via ab, and the cylinder 4a is connected to the air controller 4.
The cylinder 4a is connected to an air compressor 4c via a hose 4b provided with an air valve 4bb and an air valve 4bb, and the cylinder 4a is supported by a cylinder support frame 4d. A stopper 4da provided in the rail frame 4e engages with a stopper hole 4ea in the rail frame 4e, so that the installation position can be adjusted. The stock tank 1 is fixed to the rail frame 4e via the paper stock tank support frame 4f, and the shaft 4eb is rotatably supported by the main frame 4g.
e is designed to be able to rotate integrally with the stock tank 1. Reference numeral 5 indicates an O-ring that seals between the inner wall of the stock tank 1 and the outer wall of the dewatering tray (in the illustrated embodiment, the upper dewatering tray 2) that can be moved up and down, and 6 and 6' indicate on-off valves 6a and 6a'. Each dewatering tray 2,
3 is connected to a white water tank, 7 is an on-off valve 7a, 7
This is a suction device connected to the white water tanks 6, 6' via a pipe 7b provided with a'.

[Effect]

In order to form wet paper for test handsheet paper using the wet paper web forming device for test handsheet paper for a twin-wire paper machine according to the present invention having the above-described structure, first, either cylinder 4
By disengaging the stopper 4da provided at the end of the cylinder support frame 4d supporting the cylinder a from the stopper hole 4ea of the rail frame 4e and separating the cylinder 4a from the paper stock tank 1, the upper The dewatering tray 2 is moved in a direction away from the stock tank 1 to open the upper opening 1a of the stock tank 1. After that, a certain amount of paper stock liquid is poured into the paper stock tank 1 so that the liquid level is located at a predetermined position above the paper screen 3a at the upper end of the lower dewatering tray 3, and a suitable stirring tool, such as JIS P Stir using a perforated plate stirrer as specified in 8209. Next, the upper dewatering tray 2 is attached to the upper opening 1a of the paper stock tank 1, and at this time, the space between the inner wall of the paper stock tank 1 and the outer wall of the upper dewatering tray 2 is sealed with an O-ring 5. Ru. and air compressor 4c
The cylinder 4a is actuated to lower the upper dewatering tray 2 and immerse the paper screen 2a at the lower end in the stock liquid. Thereafter, the lowering speed of the piston rod 4aa of the cylinder 4a is lowered in advance using the air controller 4ba in accordance with the amount of white water sucked out from the stock liquid in each dewatering tray 2, 3 by the suction device 7, and the upper and lower paper screens 2a, In step 3a, the paper stock is held in place to form a wet paper web. The white water sucked out from the stock solution in each dewatering tray 2, 3 by the suction device 7 is stored in white water tanks 6, 6'. This suction dewatering method may be performed by alternately suction dehydrating from both the upper and lower sides, or by suction dehydrating from both the upper and lower sides simultaneously, but the position of the paper screen 3a at the upper end of the lower dehydrating tray 3 is kept constant. If you first dehydrate the paper stock liquid from the upper dehydration tray 2 side and then suction dehydrate it from the lower dehydration tray 3 side with the upper dehydration tray 2
Because the air existing in the inner upper part eliminates the effect that dehydration is delayed in the upper part compared to the lower part, the suction dehydration becomes smoother, improving the reproducibility of wet paper formation, and improving various aspects after making the wet paper into handmade paper. This is desirable because the variation in the characteristic values is reduced, and as a result, the correspondence between the measured values of the various characteristic values and the various characteristic values of paper produced by an actual twin-wire paper machine is improved.

The embodiment shown in FIG. 1 is an example in which only the upper dehydrating tray 2 is moved up and down, but in the present invention, the lower dehydrating tray 3 is also moved by a cylinder or the like in the same way as the upper dehydrating tray 2. Of course, a mechanism for moving it up and down may also be used.

As mentioned above, in the present invention, the paper stock liquid is sucked and dehydrated from both the upper and lower sides to form wet paper, and therefore the wet paper forming principle and means are similar to those of an actual twin-wire paper machine. The resulting wet paper is then sequentially coated,
The handmade paper obtained by pressing and drying has the characteristics of paper obtained using an actual twin-wire paper machine, especially its characteristics of low interlayer strength and small differences in fine fiber and filler distribution between the front and back sides. This makes it possible to obtain handmade paper with

In addition, in the suction dewatering of paper stock liquid, when the paper stock liquid level falls, the dewatering tray 2 and/or 3 is made to follow the descending speed of the liquid level using a moving means 4 such as a cylinder equipped with an air controller. Since the paper screens 2a and 3a are narrowed one after another, the paper screen and the liquid surface of the paper stock do not separate from each other, and suction dewatering is carried out smoothly and continuously. As a result, wet paper with less variation in quality is formed, making it possible to obtain handmade paper suitable as a test sample.

Then, the suction and dewatering of the paper stock liquid is performed using the shaft 4 of the rail frame 4e to which the paper stock tank 1 is fixed.
By rotating the eb as the center of rotation to remove the directionality of the paper screens 2a and 3a due to gravity, wet paper with less variation in quality is formed, and handmade paper is obtained which is very suitable as a test sample. It will be done.

〔Effect of the invention〕

As described in detail above, according to the method and apparatus for forming wet paper for test handsheet paper of a twin-wire type paper machine according to the present invention, the characteristics of paper obtained by an actual twin-wire type paper machine, especially its characteristics. It has become possible to obtain handmade paper with the characteristics of low interlaminar strength and small differences in fine fiber and filler distribution between the front and back surfaces, and as a result, the measured values of these characteristics are comparable to those of paper obtained with an actual twin-wire paper machine. The results now approximate and correspond well to the measured values of the properties, and the paper stock solution can be used to form handmade paper in the laboratory in the research and development of paper using a twin-wire paper machine, or in setting the paper-making conditions for that paper machine. By measuring the various properties of the paper, it becomes possible to predict in advance the various properties of paper that will be obtained using an actual twin-wire paper machine. Therefore, we will make research, paper making, process control, etc. quick and easy.
Furthermore, the occurrence of defective products can be reduced, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a front view in cross section showing the main parts of a wet paper web forming apparatus for test handsheet paper for a twin wire paper machine according to the present invention, and FIG. 2 is a front view showing a conventional wet web forming apparatus for test handsheet paper. FIG. 2 is an explanatory diagram showing the structure. DESCRIPTION OF SYMBOLS 1... Paper stock tank, 1a... Upper opening, 1b... Lower opening, 2... Upper dewatering tray, 2a... Paper screen, 3...
Lower dewatering tray, 3a... Paper net, 4... Moving mechanism,
4a...Cylinder, 4aa...Piston rod, 4
ab...Cup ring, 4b...Hose, 4ba...Air controller, 4bb...Air valve, 4c
...Air compression device, 4d...Cylinder support frame, 4da...Stopper, 4e...Rail frame,
4ea...stopper hole, 4eb...shaft, 4f...stock tank support frame, 4g...main frame, 5...O ring, 6, 6'...white water tank, 6a, 6a'...open/close valve,
6b, 6b'...Hose, 7...Suction device, 7a, 7
a'...Opening/closing valve, 7b...Pipe, 8...Cylindrical container, 9
...Grate plate, 10... Funnel, 11... Drain pipe, 12... Water receiver.

Claims (1)

[Scope of Claims] 1. A box-shaped upper dewatering tray with a paper screen attached to the lower end is inserted into the upper opening of a cylindrical paper stock tank having openings at the upper and lower parts, and is also inserted into the lower part of the paper stock tank. A box-shaped lower dewatering tray with a paper screen attached to the upper end is attached to the opening so that at least one of the trays can move up and down along the inner wall of the stock tank, and a hose is connected to each of the dewatering trays. A suction device is installed in series, and first, a certain amount of paper stock liquid is injected into the paper stock tank and stirred so that the liquid level is located at a predetermined position above the paper screen at the upper end of the lower dewatering tray, and then With the paper screen in the upper dewatering tray buried in the paper stock liquid, the paper stock liquid is sucked and dehydrated from above and below alternately or simultaneously, and the upper and lower paper screens are brought close to each other to form wet paper between the upper and lower paper screens. A method for forming wet paper for testing handmade paper for a twin-wire paper machine, characterized by the following. 2 When dewatering the stock liquid by suction from above and below, while keeping the position of the paper screen on the lower dewatering tray constant and lowering the upper dewatering tray, the paper stock liquid is first dehydrated from the upper dewatering tray side, and then 2. The method of forming a wet paper for handmade paper for testing in a twin-wire paper machine according to claim 1, wherein the wet paper is formed by dewatering from the lower dewatering tray side. 3. A cylindrical stock tank 1 having an upper opening 1a and a lower opening 1b, and an upper opening 1a of the stock tank 1.
A box-shaped upper dewatering tray 2 is installed inside the paper stock tank 1 and has a paper screen 2a attached to its lower end, and a paper screen 3a is installed in the lower opening 1b of the stock tank 1 and has a paper screen 3a attached to its upper end.
A box-shaped lower dehydration tray 3 with attached
A moving mechanism 4 that moves at least one of the upper dewatering tray 2 and the lower dewatering tray 3 up and down along the inner wall of the paper stock tank 1, and hoses 6b and 6b' with on-off valves 6a and 6a'. Each dehydration tray 2,
3, and a suction device 7 connected to the white water tanks 6, 6'. Forming device. 4. The wet paper web forming apparatus for test handsheet paper for a twin wire type paper machine according to claim 3, wherein the paper stock tank 1 is made of a transparent material at least in part from the upper part to the lower part. 5. The wet paper web forming apparatus for testing handmade paper for a twin wire type paper machine according to claim 3 or 4, wherein the paper screens 2a, 3a are detachably attached to each of the dewatering trays 2, 3. 6 The moving mechanism 4 includes a cylinder 4a in which a piston rod 4aa is connected to the upper dewatering tray 2 via a coupling 4ab, and a stopper 4da supporting the cylinder 4a and provided at the end thereof is a paper stock tank support frame. Claim 3 comprising a cylinder support frame 4d whose installation position can be adjusted by engaging with a stopper hole 4ea of a rail frame 4e to which the stock tank 1 is fixed via a cylinder support frame 4f.
5. A wet paper web forming apparatus for testing handmade paper for a twin wire paper machine according to any one of 5 to 5. 7. The wet paper web forming apparatus for testing handmade paper for a twin wire type paper machine according to claim 6, wherein the shaft 4eb of the rail frame 4e is rotatably supported by the main frame 4g.