JPH11350372A - Dehydrator for papermaking former - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dehydrator for a papermaking former capable of coping with a production system in which many kinds of products are manufactured by small lots by the same plant by adjusting the quantity of dehydration. SOLUTION: The first dehydrating equipment of this dehydrator is placed on the side of a bottom wire 2 and has plural dehydrating blades. In the forefront of the first dehydrating equipment, a wide leading blade 20 is placed and the rear curvature Ra has on itself three scraper blade 21 at a preferred interval of distance. The blade 21 has a edge-like peakness in the surface supporting a wire on the side of the entrance of the wire and the peakness scrapes water from raw paper stock 6. The scraper blade 21 and a wedge-shaped dehydrating blade 30 are placed in combination with one another on the curvature Rb. The blade 30 is adjustable in terms of both an angle and press, and the quantity of dehydration on to a top wire 3 is optimized by the adjustment operation of the blade 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper machine former dewatering apparatus applied to a paper layer forming apparatus of a paper machine twin-wire former section (including an on-top former twin-wire section).

[0002]

2. Description of the Related Art FIG. 6 shows an example of the general configuration of a generally used twin-wire former, and FIG. 7 is a partially enlarged view schematically showing the vicinity of a first dehydrator 4 in FIG. As shown in FIG. 6, a twin-wire former as a paper layer forming device of a paper machine has a configuration in which two endless wires (wire mesh) of a bottom wire 2 and a top wire 3 each form a loop. ing. The bottom wire 2 is guided by a breast roll 8 and the top wire 3
Are guided by a forming roll 9. A gap (papermaking gap) is formed by the facing surfaces of the wires 2 and 3. This gap is on the downstream side (right side in the figure)
As it becomes, it is gradually narrowed. In the loop of the bottom wire 2, a first dewatering device 4 of an initial dewatering unit is provided. As shown in FIG. 7, the first dewatering device 4 includes a plurality of scraping-type dewatering blades 21 (shaded lines). display)
Are arranged on the curvature R1 or two or more curvatures R1, R2,..., Rn at intervals.

As shown in FIG. 6, a paper raw material liquid 6 (pulp suspension) ejected from a head box 1 is sandwiched in a gap and is downstream at substantially the same speed as wires 2 and 3 (right side in FIG. 6). Direction). Along with that, the water of the paper raw material liquid 6 is dehydrated and removed by the first dehydrating device 4. That is, while traveling along the approximate curves R and R1, R2,..., Rn (see FIG. 7), the dehydration pressure generated by the scraping type dehydration blade 21 substantially causes both sides (the bottom wire 2 side and the top wire 3 side). ), The fiber mat is gradually formed, and the paper web 11 is formed. In the second dewatering device 5 provided in the loop of the top wire 3, dewatering is further performed, and a final paper layer is formed. Next, the third dewatering device 7 (suction box) and suction suction roll 10 provided in the loop of the bottom wire 2 perform suction dehydration by vacuum, and
The web 11 formed above is transferred and transferred to the next press part by a suction pickup roll (not shown). As described above, the present dewatering apparatus includes a plurality of dewatering blades 21 in each of which a gap is formed between the two wires 2 and 3 forming a loop, and is provided to face the gap via the wires 2 and 3. The paper material liquid 6 is sandwiched in the gap, the wires 2 and 3 are operated, and the paper material liquid 6 is dehydrated while moving.

[0004]

In such a twin-wire former, the suction fan (not shown) installed outside the first dehydrating device 4 adjusts the amount of vacuum air to adjust the air flow to the scraping type dehydrating blade 21 side. Although the amount of dehydration can be adjusted, the opposite side of the scraping type dehydrating blade 21
That is, the amount of water dewatered upward through the top wire 3 could not be adjusted. It is desirable to adjust the amount of dewatering upward according to changes in papermaking conditions such as paper type and papermaking speed. However, in actual operation sites, adjustments cannot be made due to the above circumstances, and the optimum papermaking condition range Had to be driven in a deviated state. For this reason,
There is no choice but to accept the decline in quality, and the response to high-mix low-volume production has been a major issue. The present invention has been made in view of such a situation, and an object of the present invention is to provide a paper machine former dewatering apparatus capable of coping with high-mix low-volume production by adjusting the amount of dewatering.

[0005]

SUMMARY OF THE INVENTION A dewatering apparatus for a paper machine former according to the present invention has been made to solve the above-mentioned problem. A wedge-shaped dewatering blade was placed in the same wire loop. Also,
The wedge-shaped dewatering blade may be configured to have an adjusting function of changing the wedge angle from outside.

The scraping type dehydrating blade scrapes off moisture from the paper raw material liquid. It is preferable that the scraping type dehydrating blade has a wire supporting surface having an edge on the wire entry side, and the edge-shaped portion is configured to scrape moisture from the paper raw material liquid. The wedge-shaped dewatering blade has an angle adjustment mechanism that can be operated from the outside,
It is preferable to provide a pressing adjustment mechanism. It is preferable that the angle adjusting mechanism is configured to support the blade body so as to swing in a predetermined range along the moving direction of the wire. Preferably, as shown in an embodiment described later, a wedge angle can be adjusted by injecting a fluid pressure from the outside.
It is preferable that the pressing adjustment mechanism supports the blade body so as to be able to advance and retreat in a predetermined range toward the wire. More preferably, a wedge angle can be adjusted by injecting a fluid pressure from the outside as shown in an embodiment described later. ADVANTAGE OF THE INVENTION According to the dehydration apparatus which concerns on this invention, the dehydration amount can be suitably adjusted by the external adjustment operation, and, thereby, an arbitrary pressure profile can be easily obtained.

The specific arrangement of the scraping-type dewatering blade and the wedge-shape dewatering blade desirably corresponds to the papermaking conditions. For example, they may be alternately arranged every other one or irregularly. The case is conceivable. Further, it is preferable that these dehydrating blades are integrated by forming the dehydrating device into a box structure.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a paper machine former dewatering apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is a partially enlarged view of the vicinity of a first dewatering device 4 in a dewatering device of a paper machine former according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view showing a modified example of an arrangement of dewatering blades. FIG. 3 is a drawing showing the wedge-shaped dewatering blade 30 of FIG.
Is a graph showing the relationship between the wedge angle and the dewatering pressure, and FIG. 5 is a graph showing the accumulated dewatering amount in the dewatering device configuration of FIG. The basic configuration of the paper machine former of the present embodiment is as shown in FIG. 6, and the numbers in the figure are also the same. In FIG. 1, the paper raw material liquid 6 moves from the first dehydrator 4 to the second dehydrator 5.

As shown in FIG. 1, the first dehydrating device 4 is disposed on the bottom wire 2 side, and its first (upstream) side
, A wide leading blade 20 is disposed. On the rear curvature Ra, three scraping-type dehydrating blades 21 are arranged at predetermined intervals, and further on the rear curvature Rb, the scraping-type dehydrating blade 21 is disposed.
And a wedge-shaped dewatering blade 30 are disposed respectively. The first dewatering device 4 has a box structure including these blades 20, 21, 30. The tips of these blades 20, 21, 30 are
It is in contact with the outer surface 2A of the bottom wire 2.

As shown in FIG. 2, the scraping type dehydrating blade 21 has a wire supporting surface 21A on which the wire enters is sharpened in an edge shape. It has become. The arrangement of the scraping type dewatering blade 21 and the wedge shape type dehydrating blade 30 on the curvature Rb (see FIG. 1) is, as shown in FIG. 2, two scraping type dehydrating blades 21 and three wedge shape type dehydrating blades. And three wedge-shaped dewatering blades 3 and three wedge-shaped dewatering blades 3 as shown in FIG.
Using 0, the trailing end may be used as the scraping-type dehydrating blade 21.

The holding structure of the wedge-shaped dewatering blade 30 will be described with reference to FIGS. (A)-(c) have shown the adjustment state of the angle which the dehydration blade and a wire make, respectively. The dewatering blade 30 has a flat portion for supporting the wire, and an inclined surface (a wedge shown in FIG. 2) forming a wedge-shaped space extending toward the upstream side in the wire running direction with respect to the wire surface on the wire entry side of the flat portion. Angle θ), and the wedge angle θ can be changed from outside. The wedge-shaped dewatering blade 30 is shown in FIGS.
As shown in each figure of (c), the first movable member 301 and the second
It is supported by a base 305 projecting above the main body of the first dewatering device 4 via a movable member 302. That is, the second movable member 302 is placed on the base 305.
5, the outer surface 2A of the bottom wire 2 while being guided by the outer surface
(A surface of the paper raw material liquid 6 along the running line) so as to be movable in a direction in which it can be separated from and contacted with the second movable member 302. A cylindrical groove 301B formed in the member 301 is slidably fitted to the shaft member 307. Thereby, the first
The movable member 301 is supported swingably about a shaft member 307.

A T-shaped dovetail groove is formed at the base end of the wedge-shaped dewatering blade 30. By fitting the tip portion 301A of the first movable member 301 into this dovetail groove, the wedge-shaped dehydrating blade 3
0 can be integrally coupled to the first movable member 301. Further, by moving the wedge-shaped dewatering blade 30 with respect to the first movable member 301 in the papermaking width direction (m / c width direction), the wedge-shaped dewatering blade 30 is inserted and removed with respect to the first movable member 301. can do.

A blade main body 306 is integrally connected to a tip of the wedge-shaped dehydrating blade 30.
When the first movable member 301 swings about the shaft member 307, the wedge-shaped dehydrating blade 30 can swing in the traveling direction of the paper raw material liquid 6 together with the blade main body 306. A surface of the blade main body 306 on the bottom wire outer surface 2A side (this is referred to as an operation surface) is inclined at an angle with respect to the bottom wire contact surface portion 306A that contacts the bottom wire 2 and the bottom wire contact surface portion 306A. And an inclined surface portion 306B. That is, a bottom wire contacting surface portion 306A that contacts the bottom wire 2 and supports the bottom wire 2 is provided on the wire exit side (downstream in the wire running direction) of the working surface of the blade body 306. On the upstream side of the contact surface 306A, that is, on the working side of the blade main body 306, on the wire entry side (upstream side in the traveling direction of the wire), it is gradually separated from the bottom wire 2 toward the upstream side in the traveling direction of the wire. Is formed. Therefore, a wedge-shaped space 306C (wedge-shaped space) is formed between the inclined surface portion 306B and the bottom wire 2 (see FIG. 3B).

An extensible tube 303 (movable tube) is interposed between the base 305 and the second movable member 302. This tube 303 is a first movable member 3
A head 310 is attached to the base 01 and can be pressed against the base 305. The fluid pressure (for example, air pressure or hydraulic pressure) inside the tube 303 can be adjusted by a fluid pressure supply / discharge device (not shown). Tube 303
The first movable member 301 can be moved relative to the base 305 while the head 310 is in pressure contact with the base 305 according to the internal pressure state. That is, the tube 3
03 increases, the head 310 moves to the base 305.
The second movable member 302 moves in a direction to separate from the base 305 while being pressed against
The paper feed liquid 6 approaches the travel line. Conversely, when the internal pressure of the tube 303 decreases, the pressure contact of the head 310 with the base 305 is weakened, and the second movable member 302 moves in a direction approaching the base 305, and the second movable member 3
02 moves in a direction away from the travel line of the paper raw material liquid 6. As described above, the second movable member 302 movable with respect to the base 305, the expandable tube 303,
A fluid pressure supply / discharge device (not shown) for adjusting the internal pressure of the tube 303 constitutes a pressing pressure adjusting mechanism 320, whereby the second movable member 302 is moved with respect to the travel line of the paper raw material liquid 6. As the wedge-shaped dewatering blade 30 moves in the same direction, the pressing pressure applied to the paper raw material liquid 6 is adjusted.

Second movable member 302 and first movable member 301
A pair of expandable and contractible tubes (movable tubes) 304a and 304b are interposed therebetween. These tubes 304a and 304b are also arranged before and after the central axis of the second movable member 302, and are attached to the second movable member 302. Each tube 304a, 304b is provided with a head 310a, 310b, respectively. Each of the heads 310a and 310b is capable of protruding from the buried state (solid line in FIG. 3B) (the position indicated by a chain line in FIG. 3B), and has an arm portion 301C formed to sandwich the first movable member 301 back and forth. , 301D.

The fluid pressure (for example, air pressure or hydraulic pressure) inside each of the tubes 304a and 304b can be independently adjusted by a fluid pressure supply / discharge device (not shown). Depending on the internal pressure state of the tubes 304a, 304b, the head 31
0a or 310b presses the first movable member 301 to the second movable member 302 while pressing against the arm portion 301C or 301D.
To be able to swing. That is, when the internal pressure of the tube 304b is increased (at this time,
The internal pressure of the tube 304a is set to a minimum or appropriately small state. (A), the arm portion 301D is pressed, and the first movable member 301 rotates around the shaft member 307 while the wedge-shaped dehydrating blade 3 is rotated.
0 is swung to the downstream side in the flow direction of the paper raw material liquid 6 (the running direction of the wire 2; see the arrow F). Conversely, tube 304
a (in this case, the tube 30
The internal pressure of 4b is set to a minimum or appropriately small state. ), The arm 301C is pressed as shown in FIG.
While the first movable member 301 rotates around the shaft member 307, the wedge-shaped dewatering blade 30 swings upstream in the flow direction of the paper raw material liquid 6 (the traveling direction of the wire 2). When the internal pressures of the tubes 304a and 304b are balanced, the first movable member 301 is in a neutral state in which the first movable member 301 is not inclined forward or backward, and the wedge-shaped dehydrating blade 30 is also in a neutral state, as shown in FIG. Become.
When the wedge-shaped dewatering blade 30 swings in this manner, the angles of the working surfaces 306A and 306B of the wedge-shaped dewatering blade 30 (blade body 306) with respect to the traveling direction of the wire (the direction in which the paper raw material liquid 6 flows), in particular, The angle of inclination (wedge-angle) formed between the inclined surface portion 306B and the bottom wire 2 is adjusted, and thus, the first swingable side with respect to the base 305 side (the second movable member 302 side). A movable member 301, telescopic tubes 304a and 304b, and these tubes 304
a, a fluid pressure supply / discharge device (not shown) for adjusting the internal pressure of 304b constitutes an angle adjusting mechanism 321. Thereby, the angle between the working surface of the wedge-shaped dehydrating blade 30 and the wire 2 is formed. Can be adjusted externally.

The internal pressure of the tube 304b is
04a, the wedge angle γ (see FIG. 1 (a)), the wedge angle β when the internal pressures of the tubes 304a and 304b are balanced (see FIG. 1 (b)), and the wedge angle β of the tube 304a. Comparing the wedge angle α in the state where the inner pressure is higher than that of the tube 304b (see FIG. 3C), the relationship γ <β <α holds, and the angle adjustment mechanism 321
By adjusting the internal pressure between the tubes 304a and 304b, the wedge angle θ can be adjusted over a wide range even during operation of the apparatus.

The bottom wire contact surface 306A constituting the working surface of the blade body 306 is
The blade body 3 is formed in a curved shape convex on the side.
06 is used in reverse with respect to the flow direction of the paper raw material liquid 6 (the traveling direction of the wire 2), that is, when the paper raw material liquid 6 is circulated in the direction opposite to the arrow F, the bottom wire contact surface portion 306A
(In this case, the right side of the bottom wire abutment surface 306A in the figures (a) to (c) is the wire entry side) is separated from the bottom wire 2 and the bottom wire abutment surface 306A. Wedge-shaped space 306 between bottom wire 2
C ′ is formed. Therefore, in this case, the wedge angle θ is formed as angles α ′, β ′, γ ′ between the bottom wire contact surface 306A and the bottom wire 2.

With the above-described structure, even when the apparatus is in operation, the wedge-shaped dehydrating blade 30 (the blade body 3) can be externally controlled by adjusting the fluid pressure of the tubes 304a and 304b in the angle adjusting mechanism 321.
06), the angles of the working surfaces 306A and 306B can be freely adjusted within a predetermined range (for example, the range of FIGS. 7A to 7C), whereby the wedge-shaped dehydrating blade 30 (the blade main body) can be adjusted. 306), the wedge angle θ
For example, it can be adjusted freely within the range of γ to α.

When the wedge angle θ is adjusted in this manner, the dewatering pressure of the paper material liquid 6 is adjusted. That is, as shown in FIG. 4, the dewatering pressure of the conventional dewatering blade (a non-wedge-shaped dewatering blade having no inclined surface) is at a level as shown in a region 43, whereas the wedge-shaped dewatering blade 30 Then, as shown by the straight line 41, the dewatering pressure can be improved. In addition, the dewatering pressure of the wedge-shaped dewatering blade 30 depends on the wedge angle θ.
The dehydration pressure decreases as the wedge angle θ increases. Therefore, the dewatering pressure can be adjusted in a wide range by adjusting the wedge angle θ of the wedge-shaped dewatering blade 30 by the angle adjusting mechanism 121.

Moreover, in the wedge-shaped dehydrating blade 30, the tube 30 in the pressing pressure adjusting mechanism 120 is used.
The pressing pressure acting on the paper raw material liquid 6 can be adjusted by the fluid pressure adjustment of 3. Due to the pressing of the movable tube 303, the dehydration pressure can be increased as compared with the case where the pressing is not performed (the straight line 41) as in the straight line 42. Therefore, the adjustment of the wedge angle θ and the tube 30
By combining with the adjustment of the pressing pressure by 3
The dehydration pressure can be adjusted over a very wide range from 1 to a straight line 42. In this manner, the wedge-shaped dewatering blades 30 are arranged in the running direction of the wires 2 and 3, that is, in the flow direction of the paper raw material liquid 6,
During the operation, the wedge angle θ and the pressing pressure are adjusted while each wedge-shaped dehydrating blade 30 is rotated and moved back and forth through the fluid pressure from the outside, so that an arbitrary pressure profile (flow of the paper raw material liquid 6) is obtained. Dehydration pressure distribution in the direction)
Can be easily obtained.

Since the dewatering pressure profile can be easily adjusted from the outside, it is possible to always perform papermaking under optimum conditions with respect to changes in basis weight, papermaking density, etc., and to constantly improve the quality of the papermaking paper. In particular, it can sufficiently cope with high-mix low-volume production. Further, since the wedge-shaped dewatering blade 30 can be inserted into and removed from the first movable member 301 by moving in the papermaking width direction, it is easy to replace the dewatering blade with another dewatering blade having a different shape. This makes it easy to change the neutral wedge angle θ (initial angle) as shown in FIG. 1B, and has the advantage that the initial angle can be set freely. The wedge-shaped dehydrating blade 30
Even if only the angle adjusting mechanism 321 for externally adjusting the angle between the working surface and the bottom wire 2 is provided,
Since the dewatering pressure can be adjusted to a certain extent over a wide range, the pressing pressure adjusting mechanism 320 for adjusting the pressing pressure of the wedge-shaped dewatering blade 30 against the paper raw material liquid 6 may be omitted.

Downstream of the first dehydrator 4, a second dehydrator 5 is disposed in a loop of the top wire 3 as shown in FIG. The second dewatering device 5 includes (1) a scraping type dewatering blade 21 used in the first dehydrator 4 or (2) a wedge-shaped dewatering blade 24 having a fixed inclination angle (wedge angle θ) (see FIG. 6), (3) With respect to the dewatering blade 21 of the above (1), the top wire 3, the raw material liquid 6,
An opposing dewatering blade having the same shape as the dewatering blade 21 that can adjust the pressing pressure against the bottom wire 2 from the outside during operation to a position facing the bottom wire 2 is used as a dewatering device. The second dewatering device 5 is provided with the first dewatering device 4 for running stability of the bottom wire 2 and the top wire 3 and for making the dehydration histories of the front and back of the paper substantially equal to produce a paper having no front and back. Top wire 3 on the other side
Are arranged in a loop. Further, the curvature of the second dehydrator 5 is inverted from the curvature of the first dehydrator 4.

Next, the operation and effects of the arrangement of the dehydrating equipment incorporating the first dehydrating equipment 4 composed of the scraping type dehydrating blade 21 and the wedge-shaped type dehydrating blade 30 will be described with reference to FIG. Head box 1
The paper raw material liquid 6 ejected from (see FIG. 6) starts to be reliably dehydrated by the collision force of the raw material jet when coming into contact with the traveling top wire 3 and bottom wire 2 wire surface. And, in front of the wide leading blade 20,
On the same scraping type dehydrating blade 21 that is sandwiched between the two wires 2 and 3 and passes over the wide leading blade 20 and is arranged on the curvature Ra and is the same as the conventional one, to the top wire 3 side and the bottom wire 2 side, respectively. Dehydration is performed,
A mat layer is formed on each wire. Then, the curvature Rb
The upper dewatering blade arrangement, that is, the dewatering area constituted by the wedge-shaped dewatering blade 30 and the scraping dewatering blade 21 is entered. At the position of the scraping type dewatering blade 21 in this dewatering region, dewatering is performed on both sides (up and down in the same drawing) by the dewatering pressure generated by the wire tension of the top wire 3 and the bending of the bottom wire 2. White water 51 dehydrated to the top wire 3 side
2 (see FIG. 2) rides on the traveling top wire 3 at substantially the same speed, and the leading dewatering blade 2 of the second dewatering device 5
2 (auto slice blade), and is discharged through a narrow throat 23 to the outside of the system. The amount of dewatering to the dewatering blade 21 side is determined by a suction fan (not shown).
Can be changed to some extent by adjusting the amount of vacuum air.

At the position of the wedge-shaped dewatering blade 30 in the dewatering area, the white water 5
2 (see FIG. 2) enters the wedge angle θ in front of the dewatering blade, thereby generating a wedge pressure. Therefore, dehydration to the lower side (bottom wire 2 side) is suppressed, and only dehydration to the top wire 3 side is performed.

Here, in the structure of the dewatering blade shown in the conventional first dewatering device 4, the dewatering pressure for performing dewatering is as follows.
Depends on the tension of the top wire 3, the bending angles of the wires at the leading and trailing ends of the dewatering blade 21 installed on a certain curvature, and the dewatering resistance of the mat layer formed between the two wires 2, 3. To do so has been revealed in our extensive research.

Next, with reference to the dehydrating apparatus configuration shown in FIG. 1, the cumulative dehydration amount profile to the top wire 3 and the bottom wire 2 will be described with reference to FIG. This figure is divided into upper and lower parts, and the upper graph shows the amount of dehydration toward the top wire 3 and the lower graph shows the amount of dehydration toward the bottom wire 2. The horizontal axis represents the direction in which the paper raw material liquid 6 flows, and the vertical axis represents the amount of dehydration at each position. The horizontal axis in the figure corresponds to the position of each dewatering blade in FIG. 1, and the flowing direction of the paper raw material liquid 6 is from left to right in FIG. In addition, the vertical axis of FIG. 5 indicates that the dehydration amount increases as going upward in the upper graph, and the dehydration amount increases as going downward in the lower graph. The dashed-dotted line in the figure shows the dewatering amount curve when the scraping type dehydrating blade 21 is used for all the dehydrating blades, and the solid lines show the scraping type dehydrating blade 21 and the wedge-shaped dehydrating blade 30. 5 shows a dehydration amount curve in the case of using in combination with. That is, the dehydration amount difference between the alternate long and short dash line and the solid line is the adjustment range (dehydration amount change range) according to the present embodiment.

In such an arrangement of the dewatering blades, the dashed line and the solid line overlap with each other up to the wide-width leading blade 20 (wide-width leading shoe) and the three scraping-type dewatering blades 21 arranged on the curvature Ra.
Both have the same dehydration curve. A wedge-shaped dewatering blade 30 is disposed on the downstream side (the left side in the figure), and dewatering by the dewatering blade 30 is performed only on the top wire 3 side. For this reason, there is a difference between the alternate long and short dash line and the solid line, and the amounts of dehydration are different. This wedge-shaped dewatering blade 30
Since the wedge angle θ can be changed as described above,
The amount of dehydration can be adjusted within the range of the hatching in FIG.

The mat amount and the density of the paper layer (mat layer) formed on the top wire 3 and the bottom wire 2 when entering the top dewatering blade 22 of the second dewatering device 5
Although there was an appropriate value to obtain the best quality, the conventional dewatering equipment configuration did not have an adjustment function, so it was forced to operate in a state deviating from the optimum range depending on the production speed and paper type, resulting in lower quality. Had been brought. In this regard, in the dewatering device of the paper machine former according to the present embodiment, as shown in FIG. 1, the dewatering blade used in the first dewatering device 4 is moved upward by changing the scraping type dewatering blade 21 and the wedge angle. And a wedge-shaped dehydrating blade 30 that can vary the amount of dehydration. That is, on the dewatering blade side combined with the wedge-shaped dewatering blade 30 that can easily change the wedge angle θ from the outside by the fluid force, white water is scraped off by the conventional scraping-type dewatering blade 21 and dewatering is performed. On the other side (anti-dewatering blade side), the amount of dewatering upward is adjusted by the pressing force of the top wire 3 against the scraping type dewatering blade 21 and the wedge pressure generated at the wedge portion of the wedge-shaped dewatering blade 30. Is possible. Here, the amount of mat formed on the top wire 3 is substantially proportional to the amount of dehydration. Further, the wedge-shaped dehydrating blade 30
By externally adjusting the wedge angle θ, the dewatering pressure changes and the dewatering amount changes, so that the amount of mat to be formed can be freely controlled. Therefore, the second
The amount of mat formed on the top wire 3 and the amount of mat formed on the bottom wire 2 entering the dewatering device 5 can be adjusted independently. Therefore, the state of the paper layer (mat layer) can be easily adjusted during operation, and it is possible to cope with an increase in production speed and a change in paper type while maintaining high quality.

In the present embodiment, the scraping type dewatering blades 21 and the wedge shape type dewatering blades 30 are alternately arranged (see FIG. 2). This combination depends on the type of paper to be made and the production speed. It can be changed as needed. In addition, the wedge-shaped dehydrating blade 30 is of a type that can arbitrarily set the wedge angle θ, but may be fixed if the operability and the adjustment ability are somewhat sacrificed. Further, in the present embodiment, the case where three scraping-type dehydrating blades 21 are arranged in front of the wedge-shaped dehydrating blade 30 has been described.
It is not limited to this because it depends on the production speed and paper type.

[0031]

According to the present invention, since the scraping-type dewatering blade and the wedge-shaped dewatering blade are arranged in the same wire loop, at the position of the wedge-shaped dewatering blade, the water is dewatered toward the dewatering blade. The wedge pressure is generated by the white water, so that the amount of dewatering on the dewatering blade side is suppressed, and the amount of dewatering on the side opposite to the dewatering blade increases. In this manner, the amount of dewatering on the opposite side of the dewatering blade can be increased, and the amount of dewatering on the dewatering blade side and the amount of dewatering on the opposite side are made different according to changes in papermaking conditions such as paper type and papermaking speed. be able to. Therefore, it is possible to respond to an increase in production speed and a change in paper type while maintaining high quality.

Further, since the wedge-shaped dewatering blade is configured so that the wedge angle can be changed from the outside, the amount of dewatering on the side opposite to the dewatering blade can be adjusted during operation. That is, by adjusting the wedge angle, the dewatering pressure changes and the dewatering amount changes.
Therefore, it is possible to cope with various types without stopping the paper machine, and it is possible to avoid a decrease in the machine operation rate.

[Brief description of the drawings]

FIG. 1 is an enlarged view partially showing the vicinity of a first dewatering device 4 in a dewatering device of a paper machine former according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view showing a modification of the arrangement of the dewatering blades.

FIG. 3 is a configuration diagram showing the wedge-shaped dewatering blade 30 of FIG. 2 alone;

FIG. 4 is a graph showing a relationship between a wedge angle and a dewatering pressure, wherein a vertical axis indicates a dewatering pressure and a horizontal axis indicates a wedge angle (θ).

5 is a graph showing the cumulative amount of dehydration in the dehydrating equipment configuration of FIG. 1, in which the vertical axis represents the amount of dehydration and the horizontal axis represents the paper raw material liquid 6.
Is the position in the flowing direction.

FIG. 6 is a schematic view showing an example of the entire configuration of a generally used twin wire former.

FIG. 7 is a partially enlarged view schematically showing the vicinity of a first dehydrating apparatus 4 in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Head box 2 Bottom wire 2A Outer surface 3 Top wire 4 1st dehydration equipment 5 2nd dehydration equipment 6 Paper raw material liquid (pulp suspension) 7 3rd dehydration equipment 8 Breast roll 9 Forming roll 10 Suction coach roll 11 Paper roll 20 Wide leading blade 21 Scraping type dehydrating blade 21A Wire supporting surface 22 Leading dehydrating blade (auto slice blade) 23 Throat 24 Wedge-shaped dehydrating blade 30 Wedge-shaped dehydrating blade 301 First movable member 301A Tip of first movable member 301 301B Cylindrical groove 301C, 301D Arm part 302 Second movable member 303, 304a, 304b Tube (movable tube) 305 Base 306 Blade main body 306A Bottom wire contact surface part (working surface) 306B Incline Surface part (working surface) 306C Dendritic space (wedge-shaped space) 307 Member shaft 310, 310a, 310b Head 320 Pressing pressure adjusting mechanism 321 Angle adjusting mechanism 41, 42 Straight line 43 Area 51, 52 White water θ, α, β, γ , Α ', β', γ 'Wedge angle

Claims (2)

[Claims] 1. A paper machine former dewatering device, wherein a scraping type dewatering blade and a wedge-shaped dewatering blade are arranged in the same wire loop. 2. The paper machine former dewatering apparatus according to claim 1, wherein the wedge shape type dewatering blade can change a wedge angle from outside.