JP2002309495A - Twin-wire former - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a twin-wire former capable of stably preserving paper quality by changing wire wrapping angle according to the paper making speed without subjecting to a large design change. SOLUTION: This twin-wire former installing wire 3 and 4 forming a space for paper making, spraying paper stuff liquid 2 from a head box 1 to the converging part of the wires 3 and 4, clamping the paper stuff liquid 2 by the wires 3 and 4 and dehydrating while transporting, installs a suction roll 16 bridged with the wire 3 and aspirating/dehydrating the paper stuff liquid 2, a breast roll 17 bridged with the wire 4 set face to the suction roll 16, dehydrating machines 5, 6, and 7 dehydrating the paper stuff liquid 2 in the paper making space, a suction couch roll 8 suction dehydrating the paper stuff liquid 2 in the paper making space, a moving means 21 for the suction roll and a wire wrapping angle changing means 20 changing a wire wrap angle θ of the suction roll 16 by moving the suction roll 16 by the suction roll moving means 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a twin-wire former for dewatering a paper raw material liquid while sandwiching and transferring a paper raw material liquid in a papermaking gap formed between two wires.

[0002]

2. Description of the Related Art As a paper layer forming apparatus of a paper machine, there is a twin wire former. This twin-wire former includes two mesh-shaped wires each formed in a loop shape, and while the paper raw material liquid runs while being sandwiched between the two wires, the paper is dewatered by various dewatering devices. As the water is removed from the raw material liquid, a fiber mat is gradually formed, which grows to form a paper web.

For example, FIG. 6 is a schematic configuration diagram showing an example of this twin-wire former. The twin-wire former will be described with reference to FIG. As shown in FIG. 6, the paper raw material liquid 2 from the inside of the head box 1 is supplied to a vacuum suction roll (forming roll) 16 and a breast roll 1.
7, a gap formed by converging two mesh-shaped wires of a first wire (# 1 wire) 3 and a second wire (# 2 wire) 4 (papermaking gap, hereinafter simply referred to as gap). Jet) toward the jet.

In the twin wire former, since the paper raw material liquid 2 lands in the papermaking gap in this way, the landing adjustment of the raw material jet (paper raw material liquid) 2 is easy and generally follows a change in the papermaking speed. It is said that the nature is high. The first wire 3 is guided by a vacuum suction roll 16 and a wire roll 18, and the second wire 4 is guided by a breast roll 17 and a guide roll (not shown). A gap is formed. The paper raw material liquid 2 forms a paper layer while traveling in the gap.

That is, the upper and lower wires 3 and 4 respectively move the paper raw material liquid 2 in the gap in a required direction (upward in FIG. 6).
The paper raw material liquid 2 moves in the gap at substantially the same speed as the wires 3 and 4 and is dewatered by the vacuum suction roll 16 and the dewatering devices 5, 6, and 7 to form a paper layer. Go. The vacuum suction roll 16 has a vacuum suction portion 16a formed so as to correspond to the section where the first wire slides, and the paper raw material liquid 2 is vacuum suctioned and dehydrated in this section. Note that a fan-shaped angle θ in which a dewatering zone in which the first wire slides on the vacuum suction roll 16 and dewaters the paper raw material liquid 2 is formed as an arc is referred to as a wire wrap angle. A first dewatering device 5, a second dewatering device 6, and a third dewatering device 7 are sequentially provided downstream of the vacuum suction roll 16, and a suction coach roll 8 and the like are provided downstream thereof. ing.

Although each of the dehydrating devices 5, 6, and 7 is simplified in FIG. 6, each of the dehydrating devices is provided with a plurality of dehydrating blades provided at intervals. The first dehydrating device 5 is provided in a loop of the curvature R of the first wire 3,
A plurality of dewatering blades are provided at intervals from each other, and the first wire 3 slides on the top surface (sliding contact surface) of these dewatering blades to travel in a loop shape with a curvature R, and the paper raw material liquid 2 is moved. The second wire 4 also runs in a loop shape having a substantially curvature R with the pinch therebetween. While the paper raw material liquid 2 travels along the curved gap approximate to the curvature R, the dewatering pressure generated by the bending of the first wire 3 and the second wire 4 along the curvature on each dewatering blade. As a result, dehydration is performed on both the wires 3 and 4, and the fiber mat gradually grows in the gap.

[0007] Similarly, the second dewatering device 6 is connected to the second wire 4.
The third dehydrating device 7 is provided in the loop of the curvature R of the first wire 3, and is provided in the loop of the curvature R of the first wire 3.
Dehydration is performed by a dehydration pressure generated by bending the wires 3 and 4 along the curvature.
In the suction coach roll 8, dewatering is performed by vacuum, and further, the formed web is transferred onto the second wire 4 via a transfer box (not shown).
It is transferred to the next press part by a suction pickup roll (not shown).

[0008]

By the way, in order to decompose the condensed paper fibers (agglomerated flocs) in the process of forming the paper web (dispersing the paper fibers evenly), it is necessary in the process of forming the paper web. It is more effective to apply a predetermined pressure to the paper material liquid in a pulsed form than to apply a predetermined pressure to the paper raw material liquid. In the conventional twin wire former described above, the vacuum suction roll is
Since dehydration (constant-pressure dehydration) is performed at a substantially constant negative pressure, the ability to decompose flocculated flocs in the paper raw material liquid is low. For this reason,
The actual situation is that flocculated flocs are decomposed by a group of fixed dewatering blades (dewatering equipment) disposed downstream of the vacuum suction roll, and the degree of fiber dispersion is maintained at an acceptable level.

The operating speed (papermaking speed) V of the papermaking machine is appropriately changed according to the specifications of the paper to be manufactured, etc., but in the vacuum suction roll 16 of the conventional twin wire former as shown in FIG. Is constant (because the length L of the dewatering zone is constant), the papermaking speed V increases and the transport speed of the raw paper liquid 2 transported between the wires 3 and 4 increases. The period during which the paper liquid 2 is dehydrated while passing through the dewatering zone is shortened. Further, since the range of adjusting the dewatering ability of the vacuum suction roll 16 by adjusting the degree of vacuum is extremely narrow, the amount M of dewatering (dehydration ability) M by the vacuum suction roll 16 increases, for example, as shown in FIG. Will decrease in accordance with

When the paper making speed V changes and the amount M of dewatering by the vacuum suction roll 16 changes, the raw material concentration of the paper raw material liquid 1 at the outlet of the vacuum suction roll 16 (the inlet of the dewatering device 5) changes. This affects the dewatering devices 5, 6, and 7 on the downstream side, and thus affects the degree of dispersion (fiber dispersion) D of the paper fibers at the outlet of the twin-wire former. Such a papermaking speed V and a fiber dispersion degree D are as shown in FIG. 7B, for example.

That is, the degree of fiber dispersion increases with an increase in the papermaking speed V (ie, a decrease in the raw material concentration of the paper raw material liquid 1 at the outlet of the vacuum suction roll 16 due to a decrease in the amount of dewatering).
After the rising tendency is saturated, the degree of dispersion of the fiber becomes unstable, that is, the degree of dispersion of the fiber is good in some cases but low in some cases. Therefore, when the papermaking speed V is lower than the predetermined speed V1, the fiber dispersion degree D cannot be maintained at the predetermined level D0, and when the papermaking speed V is higher than the predetermined speed V2, the fiber dispersion degree becomes unstable, and in any case, Paper quality cannot be maintained.

Japanese Patent Application Laid-Open No. 9-228286 discloses a technique in which even if the papermaking speed V is changed, the paper quality can be maintained by keeping the dewatering amount (dewatering capacity) M by the vacuum suction roll 16 within a certain range. Is disclosed. Hereinafter, the principle of this conventional technique will be described with reference to FIG. In addition,
The same components as those of the twin wire former already described with reference to FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted.

In the twin wire former, a breast roll (lead-in roll) 17 is provided with a moving mechanism (not shown). Therefore, in this twin-wire former, for example, when the papermaking speed V decreases,
By moving the breast roll 17 from the position indicated by the double-dashed line in FIG. 8 to the position indicated by the solid line in FIG. 8, the amount M of dewatering by the vacuum suction roll 16 is maintained within a predetermined range, and the paper quality is improved. Can hold.

[0014] That is, when the machine speed V is lowered, while still i.e. dewatering zone length L of the wire wrap angle theta is theta ₁ is L ₁ for a period of time in the paper raw material liquid 2 passes through the dewatering zone (= dehydration period) T is enlarged and the paper raw material liquid 2 is excessively dehydrated. For this reason, the wire wrap angle θ is reduced from θ ₁ to θ ₂ by separating the breast roll 17 from the suction roll 16 by an amount corresponding to the reduced paper making speed V, that is, the dewatering zone length L is changed from L ₁ to L _2. Dehydration period T
Can be maintained within a predetermined period, and the paper quality can be maintained by maintaining the dewatering amount M within a predetermined range.

The optimal position of the landing point of the paper raw material liquid 2 between the wires 3 and 4 is, for example, that the second wire 4 is the first wire 3
Is a nip point Ps between the second wire 4 contacting the vacuum suction roll 16 through the vacuum suction roll 16 and the vacuum suction roll 16. As shown in FIG. 9, when the breast roll 17 is moved to change the wire wrap angle θ from θ ₁ to θ ₂ , the position of the nip point Ps also changes from Ps ₁ to Ps ₂ .

As shown by a two-dot chain line in FIGS. 8 and 9,
In wire-wrap angle theta _1, when the head box 1 has been set in position and the injection direction to inject the paper raw material liquid 2 to the nip point Ps _1, was changed to the wire wrap angle theta _2, the When the paper stock liquid 2 is injected with the setting,
Blocked by the peripheral surface of the vacuum suction roll 16 (= position Ps _1), to the nip point Ps ₂ corresponding to the wire wrap angle theta ₂ can not be injected paper raw material liquid 2.

For this reason, the conventional apparatus is further provided with a moving mechanism (not shown) for moving the head box 1, and this moving mechanism allows the head box 1 to be moved as shown in FIGS.
In the above, the moving head box 1 is moved in parallel from the state shown by the two-dot chain line to the state shown by the solid line, and further, the nip is changed by changing the injection angle, for example, by adjusting the angle of the injection port of the head box 1. and to be able to inject the paper raw material liquid 2 to the point Ps _2.

The diameter of the pipe for supplying the paper raw material connected to the head box 1 is naturally determined according to the machine width (width of the paper machine) and the like. Is done. Conventionally, a mechanism for adjusting the injection angle is provided in the head box 1, but unlike such an adjustment mechanism, the head box 1 to which the large-diameter pipe is connected is moved (head box position). In particular, a large-scale device is required to make the device movable), and a large design change is required particularly from around the head box, from the conventional configuration, which is extremely difficult in practice.

The present invention has been devised in view of the above-described problems, and the paper quality is stably maintained by changing the wire wrap angle in accordance with the papermaking speed without making a significant design change. An object of the present invention is to provide a twin-wire former that can be used.

[0020]

According to a first aspect of the present invention, there is provided a twin wire former according to the present invention comprising a first wire and a second wire that converge with each other to form a papermaking gap. A twin-wire former for injecting a liquid into a converging portion of the two wires in a jet form and dewatering while sandwiching and transferring the paper raw material liquid to the papermaking gap by the two wires, A suction roll disposed at an upstream end, around which the first wire is wound, and for sucking and dewatering the paper raw material liquid; and a suction roll disposed at an upstream end of the papermaking gap so as to face the suction roll. (2) a breast roll over which the wire is wound, a dewatering device disposed downstream of the suction roll and the breast roll, and a dewatering device for dewatering the paper raw material liquid in the papermaking gap; and a dewatering device disposed downstream of the dewatering device. And A suction couch roll for sucking and dewatering the paper raw material liquid in the papermaking gap by contacting one of the two wires, and a suction roll moving means, and the suction roll moving means And a wire wrap angle changing means for changing a wire wrap angle of the suction roll by moving the suction roll.

According to a second aspect of the present invention, there is provided the twin wire former according to the first aspect, wherein the suction roll moving means swings the suction roll about the axis of the suction coach roll. It is characterized by: A twin wire former according to a third aspect of the present invention is the twin wire former according to the second aspect, wherein the suction roll and the dewatering device are integrally moved.

A twin wire former according to a fourth aspect of the present invention is the twin wire former according to any one of the first to third aspects, wherein the wire wrap angle changing means moves the breast roll. It is characterized by having transportation means. A twin wire former according to a fifth aspect of the present invention is the twin wire former according to any one of the first to fourth aspects, wherein the raw material concentration of the paper raw material liquid at the outlet of the suction roll is detected or estimated. A material concentration detecting means is provided, and the wire wrap angle changing means changes the wire wrap angle based on the detection information of the material concentration means so that the material concentration becomes a predetermined concentration.

According to a sixth aspect of the present invention, in the twin wire former according to the fifth aspect, the raw material concentration detecting means detects a flow rate of the white water sucked and dewatered from the paper raw material liquid by the suction roll. The apparatus is characterized by comprising white water flow rate detecting means for detecting, and estimating the raw material concentration based on detection information of the white water flow rate detecting means.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described. FIGS. 1 to 4 show a twin-wire former as a first embodiment of the present invention, and FIG. 1 is a schematic side view showing the entire configuration thereof. Fig. 3 is a diagram for explaining the operation and effect, and is a schematic side view showing the entire structure. Fig. 3 is a diagram for explaining the operation and effect. FIG. 4 is a schematic diagram showing a correlation with the degree of fiber dispersion D of the paper, and FIG. 4 is a diagram for explaining the operation and effect, and is a schematic side view showing the configuration of a main part thereof.

As shown in FIG. 1, the twin wire former according to the first embodiment of the present invention has a wire wrap angle changing mechanism (wire wrap angle changing means) 20 having a suction roll moving mechanism (suction roll moving means) 21. This is characterized in that the suction roll moving mechanism 21 can move the vacuum suction roll (suction roll) 16 to adjust the wire wrap angle θ, and the other parts are configured in the same manner as the above-described prior art. Have been.

That is, the first wire (# 1 wire) 3 and the second wire (# 2 wire) 4 are connected between the vacuum suction roll (forming roll) 16 and the breast roll 17.
The paper raw material liquid 2 is jetted from the inside of the head box 1 toward a gap (papermaking gap, hereinafter also simply referred to as a gap) formed by converging a plurality of mesh-shaped wires. I have.

The first wire 3 is guided by a vacuum suction roll 16 and a wire roll 18 and the like, and the second wire 4 is guided by a breast roll 17 and a guide roll (not shown). And the paper raw material liquid 2 is transferred to the wires 3 and 4
It moves in the gap at a substantially constant speed. The gap is gradually narrowed toward the downstream in the running direction, and the paper raw material liquid 2 forms a paper layer while running in the gap.

The vacuum suction roll 16 is provided with a suction portion 16a to which a vacuum or a negative pressure close to the vacuum is supplied corresponding to a section where the first wire slides, and the paper raw material liquid 2 is supplied in this section. It is designed to be sucked and dehydrated. On the downstream side of the vacuum suction roll 16, fixed dewatering blade groups such as a first dewatering device 5, a second dewatering device 6, and a third dewatering device 7 are provided in this order. A coach roll 8 and the like are provided.

Each of the dehydrating units 5, 6, and 7 is simplified in FIG. 1, but is constituted by a plurality of dehydrating blades provided at intervals. The first dehydrating device 5 is provided in a loop of the curvature R of the first wire 3,
A plurality of dewatering blades are provided at intervals from each other, and the first wire 3 slides on the top surface (sliding contact surface) of these dewatering blades to travel in a loop shape with a curvature R, and the paper raw material liquid 2 is moved. The second wire 4 also runs in a loop shape having a substantially curvature R with the pinch therebetween. While the paper raw material liquid 2 travels along the curved gap approximate to the curvature R, the dewatering pressure generated by the bending of the first wire 3 and the second wire 4 along the curvature on each dewatering blade. As a result, dehydration is performed on both the wires 3 and 4, and the fiber mat gradually grows in the gap.

Similarly, the second dehydrating device 6 includes the second wire 4
The third dehydrating device 7 is provided in the loop of the curvature R of the first wire 3, and is provided in the loop of the curvature R of the first wire 3.
Dehydration is performed by a dehydration pressure generated by bending the wires 3 and 4 along the curvature.
In the suction coach roll 8, dehydration is performed by a vacuum or a negative pressure close to the vacuum, and further, a paper web is formed via a transfer box (not shown).

Here, the wire wrap angle changing mechanism 20 which is a feature of the present invention will be described. As described above, the wire wrap angle changing mechanism 20 includes the suction roll moving mechanism 21 for moving the suction roll 16 as shown in FIG. As shown in FIG. 1, the suction roll moving mechanism 21 includes a pair of arms that support the suction roll 16 and the dewatering devices 5, 6, 7 at both ends in the width direction (the direction perpendicular to the paper surface in FIG. 1). 22 and 22 are provided. The suction roll 16 is rotatably attached to the end 22B side of each arm 22 via support members 16A, 16A that support the roll body at both ends in the width direction. In addition, each of the dehydrating devices 5, 6, and 7 includes a connecting member 5A, 6A,
Both ends in the width direction are fixed to the arm 22 via 7A.

Each arm 22 has one end 22A mounted on a connecting member 23 and rotatably mounted on the shaft 8A of the suction coach roll 8, and swings about the axis CL of the suction coach roll 8. It can move. The other end 22B of each arm 22 is pivotally supported by one end (drive end) 24A of an extendable telescopic mechanism 24, and the other end 24B of the telescopic mechanism 24 is pivoted by the device frame 30. It is supported as much as possible.

The telescopic mechanism 24 here is constituted by a screw jack, and the ram 24b screwed to the screw rod 24a is advanced and retracted on the screw rod 24a by rotating the screw rod 24a by a drive mechanism (not shown). You can do it. The expansion mechanism 24 is not limited to a screw jack, but may be, for example, a hydraulic jack, a hydraulic cylinder, or the like.

The wire wrap angle θ can be changed by expanding and contracting the screw jack 24. That is, for example, when the jack 24 is retracted from the state shown in FIG. 1, the jack 24 swings around the end 24B in response thereto, and the arm 22 moves the end 22B to the tip 24A of the jack 24. 1, swings counterclockwise in FIG. 1 around the axis CL of the suction coach roll 8.

Then, the suction roll 16 (here, further,
The dehydrating devices 5, 6, and 7) are integrated with the arm 22 as shown in FIG.
2, the wire wrap angle changing mechanism 20 is omitted).
From the state indicated by the dotted line (the state corresponding to FIG. 1) to the solid line
Move to the state. At this time,
The tension holding mechanism (not shown)
The tension of 3, 4 is maintained. I
Therefore, the traveling paths of the wires 3 and 4 are two points in FIG.
The state shown by the difference line changes to the state shown by the solid line, and the suction low
The nip point of the second wire 4 with respect to the
Yarap angle θ is θ ₁From θ_TwoChanged to
It is.

The twin wire former according to the first embodiment of the present invention is configured so that the wire wrap angle θ can be changed in this way. Therefore, for example, the operator operates the wire wrap angle changing mechanism 20 in accordance with the papermaking speed. The paper quality can be maintained at a high level by appropriately changing the wire wrap angle θ by operating. That is, as described above as a problem of the prior art, when the amount M of dewatering by the vacuum suction roll 16 changes, the paper raw material liquid 1 at the outlet portion of the vacuum suction roll 16 (between the vacuum suction roll 16 and the dewatering device 5). The raw material concentration deviates from the predetermined range, and the degree of dispersion (fiber dispersion) D of the paper fibers at the outlet of the twin wire former cannot maintain the predetermined degree of dispersion or becomes unstable.

In the twin wire former, when the papermaking speed is reduced, the expansion / contraction mechanism 24 of the wire wrap angle changing mechanism 20 (suction roll moving mechanism 21) is retracted to separate the suction roll 16 from the breast roll 17. The wire wrap angle θ, that is, the dewatering zone length L
To shrink. Thereby, even if the papermaking speed decreases, the period during which the paper raw material liquid 2 passes through the dewatering zone can be maintained within a predetermined period, and as shown in FIG. Range) W, the degree of dispersion D of the paper fibers at the exit of the twin-wire former can be stably maintained at a predetermined degree of dispersion D0 or more.

Similarly, when increasing the papermaking speed,
By extending the expansion / contraction mechanism 24 to bring the suction roll 16 close to the breast roll 17 to increase the length L of the dewatering zone, the dewatering amount M by the vacuum suction roll 16 is maintained within a predetermined range W, and the twin-wire former is maintained. The degree of dispersion D of the paper fibers at the outlet can be stably maintained at a predetermined degree of dispersion D0 or more.

The optimum point of the landing point of the paper raw material liquid is the nip point Ps between the second wire 4 and the suction roll 16 as described above for the prior art. In the related art, as described above with reference to FIG. 9, for example, when the wire wrap angle θ is reduced from θ ₁ to θ ₂ , the paper raw material liquid 2 lands at the nip point Ps ₂ corresponding to the wire wrap angle θ _2. In order to prevent this, the jet angle of the paper material liquid 2 of the head box 1 must be changed and the head box 1 must be moved so that the paper material liquid 2 is not blocked by the peripheral surface of the suction roll 16. .

On the other hand, in the present twin-wire former, the suction roll 16 swings about the axis CL of the suction coach roll 8, so that the suction roll 16 is moved from the breast roll 17 as shown in FIG. When the wire wrap angle θ is reduced from θ ₁ to θ ₂ by being separated from each other, the suction roll 16 moves from a position indicated by a two-dot chain line to a position indicated by a solid line in the drawing.

In this case, the suction roll 16 is used to
Will move to the side away from the injection route of
In this twin wire former, compared to the conventional technology,
The peripheral surface of the suction roll 16 is ejected from the head box 1.
Nip point Ps _TwoI shielded you from
Without having to move the headbox 1
Also change the spray angle of the paper stock liquid 2
Nip point Ps after changing lap angle_TwoEasy to land on
You. An arrangement for supplying a paper raw material liquid connected to the head box 1
Tubes are generally large in diameter, so the headbox 1
It is practically very difficult to move. Against this
In general, the head box 1 is generally
To swing the box 1 itself,
And a predetermined angle (for example, about ± 5 degrees) of the paper raw material liquid 2
The injection angle can be adjusted.

Therefore, in the present twin-wire former, it is possible to land the paper raw material liquid 2 at the optimum point by the head box 1 only by utilizing the conventional mechanism for adjusting the ejection angle of the head box 1. There is an advantage that the paper quality can be stably maintained irrespective of the papermaking speed without providing a large-scale device for moving the head box 1 like the conventional device shown in FIG.

When the wire wrap angle θ is changed, the suction roll moving mechanism 21 rotates the suction roll 16 and the dewatering device 5 around the axis CL of the suction coach roll 8.
Since the members 6 and 7 are swung together, the positional relationship among the suction roll 16, the dewatering devices 5, 6, 7 and the suction coach roll 8 can be maintained, and the dewatering performance / fiber dispersion performance of these devices can be maintained constant. There are advantages.

Next, a second embodiment will be described.
FIG. 5 is a schematic side view showing the overall configuration of a twin-wire former as a second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals in FIG. 5, and the description thereof will be omitted. The twin wire former according to the second embodiment of the present invention differs from the first embodiment in the configuration of the wire wrap angle changing mechanism (wire wrap angle changing means). For other configurations,
Since it is the same as the first embodiment, only the wire wrap angle changing mechanism (wire wrap angle changing means) will be described below.

The wire wrap angle changing mechanism according to the present embodiment is different from the wire wrap angle changing mechanism 20 of the first embodiment shown in FIG. 1 in that a breast roll moving means for moving the breast roll 17 is added as a component thereof. ing. That is, the wire wrap angle changing mechanism 20 of the present embodiment
A is, as shown in FIG. 5, a suction roll moving mechanism 21;
A breast roll moving mechanism (breast roll moving means) 25 for moving the breast roll 17 is provided.

The breast roll moving mechanism 25 is constructed in substantially the same manner as the suction roll moving mechanism 21, and the breast roll 1
7 is provided with a pair of arms 26 and 26 supporting both ends in the width direction (the direction perpendicular to the paper surface in FIG. 5), and a screw jack (expansion / contraction mechanism) 24. The breast roll 17 has one end 26B of each arm 26 via support members 17A, 17A supporting the roll body at both ends in the width direction.
Each is rotatably mounted on the side.

The other end 26A of each arm 26 is swingably connected to a connecting member 27 by a pin 27A.
It is connected to the device frame 31 via the connection member 27. One end 26B of each arm 26 is swingably attached to a drive end 24A of the extension mechanism 24. Therefore, by extending and retracting the screw jack 24 and swinging the arm 26 about the pin 27A, the swing end 2
The breast roll attached to 6B can be moved. For example, when the jack 24 of the breast roll moving mechanism 25 is retracted from the state shown in FIG. 5, the jack 24 accordingly tilts downward around the base end 24B in the figure, and the arm 26 swings. End 2
6B is swung about the pin 27A while being tilted with respect to the tip 24A of the jack 24, whereby the breast roll 16 moves from the position shown by the solid line to the position shown by the two-dot chain line in FIG. θ is reduced from θ ₁ to θ ₂ .

The twin-wire former according to the second embodiment of the present invention is configured as described above, in which the suction roll 16 is moved by the suction roll moving mechanism 21, and the breast roll 1 is moved by the breast roll moving mechanism 25.
7, the wire wrap angle θ can be adjusted. As in the first embodiment, for example, the operator operates the moving mechanisms 21 and 25 according to the papermaking speed to adjust the wire wrap angle θ. Even if the papermaking speed changes, the amount M of dewatering by the vacuum suction roll 16 can be maintained within a predetermined range, and the degree of dispersion D of the paper fibers at the outlet of the twin wire former can be stably maintained at a predetermined degree of dispersion D0 or more. Can be maintained.

Since the breast roll 17 can be further moved as compared with the first embodiment, the breast roll 17 and the suction roll 16 with respect to the head box 1 can be moved.
Adjustment range of each relative positional relationship, and thus the suction roll 1
The adjustment range of the nip point of the second wire 4 with respect to 6 is widened. Therefore, even when the wire wrap angle θ is changed, it is possible to maintain the nip point on the injection route of the paper material liquid 2 without changing the injection angle of the head box 1 (the paper material liquid is It is possible to land at the nip point). Alternatively, by changing the ejection angle of the head box 1, the position range of the nip point where the paper stock liquid can land can be expanded, the adjustment range of the wire wrap angle θ can be expanded, and the paper quality can be maintained (operable). There is an advantage that the paper making speed range can be expanded.

The twin-wire former of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in each of the above-described embodiments, the change of the wire wrap angle θ is performed by the operator appropriately operating the expansion / contraction mechanism 24 of the suction roll moving mechanism 21 and the breast roll moving mechanism 25 according to the papermaking speed. However, a control means may be provided, and the operation of the telescopic mechanism 24 may be automatically controlled by the control means. If the papermaking speed changes as described above, the concentration of the paper raw material liquid 2 at the outlet of the suction roll 16 changes, which may adversely affect the paper quality. Therefore, a raw material concentration detecting means for detecting the raw material concentration of the paper raw material liquid 2 at the outlet of the suction roll 16 is provided, and based on the detected information, the control means controls the operation of the expansion and contraction mechanism 24 so that the raw material concentration becomes a predetermined concentration. By doing so, it is possible to maintain the paper quality regardless of the papermaking speed.

That is, if the raw material concentration of the paper raw material liquid 2 at the outlet of the suction roll 16 is higher than a predetermined concentration, it is determined that the suction roll 16 is excessively dehydrated, and the suction roll moving mechanism 21 and the breast roll moving mechanism are used. By operating the mechanism 25, the wire wrap angle θ (dewatering zone length L) of the suction roll 18 is reduced. On the other hand, if the raw material concentration is lower than a predetermined concentration, the suction roll 16 is sufficiently dewatered. That is, the suction roll moving mechanism 21 and the breast roll moving mechanism 25 are operated to increase the wire wrap angle θ.

Such a raw material concentration detecting means includes, for example,
It is provided with a flow rate sensor and a density sensor provided in a discharge path of the white water sucked / dewatered by the suction roll 16, and a calculation means functionally provided in the control means. The flow rate of the white water and the paper component (raw material) concentration detected by a sensor that detects the concentration based on the transmittance of the white water) and the paper component (raw material) concentration are supplied to the head box 1 that has been input in advance (at the entrance of the suction roll 16).
From the supply amount of the paper raw material and the raw material concentration, the raw material concentration at the outlet of the suction roll 16 can be estimated by the calculating means.

Alternatively, if the raw material concentration of the white water sucked / dehydrated by the suction roll 16 is substantially constant or can be predicted, the raw material concentration detecting means can be constituted by the flow rate sensor and the calculating means.

[0054]

As described above in detail, according to the twin wire former of the present invention, the wire wrap angle can be changed by the wire wrap angle changing means, so that the wire wrap angle can be changed according to the papermaking speed. By changing this, the amount of dewatering by the suction roll and thus the raw material concentration of the paper raw material liquid at the outlet of the suction roll can be maintained within a predetermined range, and the paper quality at the outlet of the twin-wire former can be stably maintained.

Further, since the wire wrap angle is changed by moving the suction roll, the suction roll and the nip point of the suction roll and the second wire can be moved in substantially the same direction. For this reason, even if the wire wrap angle is changed,
By simply changing the ejection angle of the head box using an adjustment mechanism provided conventionally, it becomes possible to eject the paper material to the nip point without being interrupted by the peripheral surface of the suction roll. There is no need to move the box.

Therefore, the paper quality can be maintained stably by changing the wire wrap angle in accordance with the papermaking speed without making a drastic design change such as providing a moving mechanism in the head box. There is an advantage of becoming. According to the twin wire former of the present invention, the suction roll moving means changes the wire wrap angle by swinging the suction roll about the axis of the suction coach roll, thereby changing the wire wrap angle. However, there is an advantage that the positional relationship between the suction roll and the suction coach roll can be kept constant, and the dewatering performance and the fiber dispersion performance can be maintained.

According to the twin wire former of the present invention, since the suction roll and the dewatering device are moved integrally, the positional relationship between the suction roll and the dewatering device can be changed even if the wire wrap angle is changed. There is an advantage that it can hold, and can hold dehydration performance and fiber dispersion performance. According to the twin wire former of the present invention, the breast roll can be moved by the breast roll moving means, so that the adjustment range of the positional relationship between the head box, the suction roll and the breast roll can be expanded. Therefore, it is possible to increase the wire wrap angle at which the paper material liquid can be jetted to the nip point between the suction roll and the second wire, and to stably maintain the paper quality over a wider range of papermaking speeds. According to the twin-wire former of the present invention, there is an advantage that the wire wrap angle is adjusted so that the raw material concentration becomes a predetermined concentration based on the raw material concentration of the paper raw material liquid at the outlet portion of the suction roll. Therefore, when the papermaking speed is changed, the wire wrap angle is automatically controlled so that the raw material concentration becomes a predetermined concentration. There is an advantage that the paper quality can be stably maintained.

According to the twin wire former of the present invention, the raw material concentration of the paper raw material liquid on the downstream side of the suction roll is estimated based on the flow rate of the white water sucked and dewatered from the paper raw material liquid by the suction roll. Therefore, there is an advantage that such a raw material concentration can be detected by such a simple configuration.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an entire configuration of a twin-wire former as a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation and effect of the twin-wire former as the first embodiment of the present invention, and is a schematic side view showing the entire configuration.

FIG. 3 is a diagram for explaining the operation and effect of the twin-wire former as the first embodiment of the present invention, and is a schematic diagram showing a correlation between the dewatering amount M and the degree of fiber dispersion D of paper. .

FIG. 4 is a diagram for explaining the operation and effect of the twin-wire former as the first embodiment of the present invention, and is a schematic side view showing a main part configuration.

FIG. 5 is a schematic side view showing an entire configuration of a twin-wire former as a second embodiment of the present invention.

FIG. 6 is a schematic side view showing an example of the configuration of a conventional general twin wire former.

7A and 7B are diagrams for explaining the problem of the conventional twin wire former, in which FIG. 7A is a schematic diagram showing a correlation between a papermaking speed V and a dewatering amount M by a vacuum suction roll, and FIG. FIG. 4 is a schematic diagram illustrating a correlation between a speed V and a fiber dispersion degree D of paper.

FIG. 8 is a schematic side view showing an example of the configuration of a conventional twin-wire former.

FIG. 9 is a schematic main part side view for explaining a problem of the conventional twin wire former.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Head box 2 Paper raw material liquid 3 1st wire (# 1 wire) 4 2nd wire (# 2 wire) 5 1st dehydration equipment 5A, 6A, 7A Connection member 6 2nd dehydration equipment 7 Brother 3 dehydration equipment 8 Suction coach Roll 8A Shaft 16 Vacuum suction roll (forming roll) 16A Support member 16a Suction unit 17 Breast roll 17A Support member 18 Wire roll 20, 20A Wire wrap angle changing mechanism (wire wrap angle changing means) 21 Suction roll moving mechanism (suction roll) 22 and 26 arms 22A, 22B, 26A and 26B Ends of arms 23 Connecting members 24 Jacks (expansion and contraction mechanism) 24A and 24B Ends of jacks 24a Screw rods 24b Ram 25 Breast roll movement mechanism (breast roll movement means) 27 connection member 27A pin 30, 31, 32 Axis L of the location frame CL suction couch roll, L _1, L ₂ dewatering zone length Ps, Ps _1, Ps ₂ nip point θ, θ _1, θ ₂ wire wrap angle

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masanobu Matsumoto 5007 Itozakicho, Mihara-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Paper and Printing Machinery Division F-term (reference) 4L055 CE45 CE46 CE52 CE57 CE61 CE90 DA09 DA12 DA15 DA16 DA17 FA09

Claims (6)

[Claims] A first wire and a second wire which are converged with each other to form a papermaking gap, and a paper material liquid is jetted from a head box to a converging portion of the two wires in a jet form, so that the two wires are formed. A twin-wire former that interposes and transports the paper material liquid in the papermaking gap to dehydrate the paper material liquid, wherein the first wire is disposed at the upstream end of the papermaking gap, A suction roll for sucking water and dewatering; a breast roll disposed at an upstream end of the papermaking gap so as to face the suction roll and around which the second wire is wound; and a downstream side of the suction roll and the breast roll. A dewatering device for dewatering the paper raw material liquid in the papermaking gap; and a dewatering device disposed downstream of the dewatering device and in contact with one of the two wires to form the papermaking liquid. The paper field in the gap Suction suction roll for sucking and dehydrating the liquid; and wire wrap angle changing means for changing the wire wrap angle of the suction roll by having the suction roll moving means and moving the suction roll by the suction roll moving means. A twin-wire former characterized by being configured. 2. The twin-wire former according to claim 1, wherein the suction roll moving means swings the suction roll about an axis of the suction coach roll. 3. The twin-wire former according to claim 2, wherein the suction roll and the dewatering device are moved integrally. 4. The twin wire former according to claim 1, wherein said wire wrap angle changing means includes a breast roll moving means for moving said breast roll. 5. A raw material concentration detecting means for detecting or estimating a raw material concentration of the paper raw material liquid at an outlet portion of the suction roll, wherein the wire wrap angle changing means performs the processing based on detection information of the raw material concentration means. The twin-wire former according to any one of claims 1 to 4, wherein the wire wrap angle is changed so that the raw material concentration becomes a predetermined concentration. 6. The raw material concentration detecting means comprises white water flow detecting means for detecting a flow rate of white water sucked and dewatered from the paper raw material liquid by the suction roll, and the detection information of the white water flow detecting means is provided. 6. The twin wire former according to claim 5, wherein said raw material concentration is estimated based on said raw material concentration.