JPS5942120B2 - Two wire paper making device in paper machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method in which water is simultaneously dehydrated from the paper web (paper web) through two wires (paper making nets) during the web (paper web) forming process in an essential part of the process. One of the two wires is a web conveying wire and the other is a web covering wire, and within the loop formed by the web conveying wire there are two suction (suction) rolls, of which the direction of travel of the paper web is The first suction roll is a web-forming roll, the second suction roll is a couch roll, and the web-forming opening is provided with a fan-shaped body for dewatering constituted by at least one suction chamber. During web forming, the fan is covered by a web conveying wire and a web sheathing wire, and dewatering is performed first on the fan by pressing the web conveying wire and the web sheathing wire together, and before the web forming rolls. , the web conveying wire and the web sheathing wire form a throat into which the fiber slurry is fed by the headbox of the paper machine, and the web conveying wire and the web sheathing wire form at least a web The present invention relates to a two-wire paper machine in a paper machine in which the web conveying wire runs together diagonally upward from the beginning of the sector of the forming roll to the point where it reaches the couch roll adjoining it.

Recently, a number of so-called two-wire paper machines have been developed in which different ways of draining the paper web being formed are carried out simultaneously in two directions.

As can be seen, this operating principle accelerates draining.

Additionally, the resulting paper web has a more homogeneous composition than that produced with conventional endless Fourdrinier.

In a conventional two-wire paper machine for symmetrical draining, the path between the web conveying wire and the web sheathing wire is vertical, and the raw material is fed from above between the web forming wire and the web sheathing wire. Ta.

The currently used two-sheet wire paper machines perform the feed direction of the feed suspension between the web-forming wire and the web-covering wire, and the formation and condensation of the web between the web-forming wire and the web-covering wire. It differs from conventional types by the way in which the two wires have their connecting run located within the passageway section of the two wires.

Such a two-wire paper machine combination is designed such that the web conveying wire and the web sheathing wire must run along the oil path immediately following the headbox and at the beginning where most of the drainage occurs. It has been found that it is preferable in most cases to facilitate drainage by centrifugal force.

One design solution of this kind is British Patent No. 993837
This is illustrated by the configuration described in that patent, in which the wire passes around two rolls so that their path is S-shaped.

A disadvantage of this type of construction and its different variations is that the wire overlapping the tenth wire as the inner wire runs over the second wire as the outer wire.

This means that the wires move toward each other and that movement can damage the formed fibrous web running between the wires by disturbing the fiber orientation of the web or reducing the strength of the web.

Previously known designs in which both wires pass through a common path and the paper web thus produced is bent in only one direction are those described in U.S. Pat. No. 3,438,854 and U.S. Pat. No. 3,565,757. Including those listed in .

These known designs have the disadvantage that the wire passages are created by a number of types of devices that rub the wire (curved shoe suction or equivalent) and have a strong frictional effect on the wire.

The considerable void space required by such an arrangement in the longitudinal direction of the paper machine can also be considered an objectionable feature.

Furthermore, unlike the above-mentioned design, this patent application also has the following features: j
A web-forming twin-wire device combining the jaws can be exemplified as described in U.S. Pat.

The object of this invention is to further increase the drainage capacity and the possibility of controlling the direction of drainage and to improve the course and guidance of the wire, as disclosed in US Pat. No. 3,997.
The configuration described in the '390 specification is an improvement.

A key feature of the invention is that during the travel of the web conveying wire and the web covering wire between the web forming roll and the couch roll, the path of the two wires is such that the wires do not engage and rub against stationary members. Determined by guidance by one or several rotating wet paper web guiding rolls located within the loop of the web sheathing wire, said wet web guiding rolls guiding these wires in said path between the web conveying wire and the web sheathing wire. The pressure applied to the web causes the cilanib to square towards the side of the conveying wire, so that the bend in the wire running towards the wet paper guide roll web conveying wire and the connecting run of the web conveying wire and the web-covered wire causes the web to All on the side of the web sheathing wire about the plane passing through the centerline of the forming roll and couch roll.

In web-forming molds similar to those described in US Pat. No. 3,997,390, the majority of the drainage occurs on the web-forming rolls.

If the drainage is to be increased at this stage, the increase in drainage is first carried out towards the web transport wire and into the web or web forming rolls at a given paper machine speed, wire mesh and wire tension. obtain.

To increase drainage in this way, the suction fan of the web-forming roll covered by both wires must also increase to a corresponding extent.

A canopy corner or sector is formed by guiding both wires by at least one guide roll so that the course of the wire has a slight bend towards the web-carrying wire between the web-forming roll and the couch roll. It can be made relatively large.

This arrangement provides further advantages.

That is, when using plastic wires that tend to stretch easily, the wires can be held tightly together without undue tension during bonding runs.

It is important to hold both wires together in terms of structure and strength of the fibrous web that is being formed between the wires.

This arrangement reduces wire slippage on the web forming roll and couch roll.

The centrifugal force at the web forming roll before the wet paper guide roll is in the opposite direction.The direction of the wire course is such that the centrifugal force at the wet paper guide roll throws out the water extruded from the web between the two W/Vs. It is also possible to make changes.

In some cases, for example when the paper machine runs at low speed,
Or when using easily draining quality raw materials, it is possible to use normal wire guiding rolls in this regard.

However, in most cases, this wet web guiding roll cannot resemble other wire guiding rolls.

This situation is due to the position of this roll, since the sand inch structure made by the two wires and the fibrous web between them is subject to a compression process at this roll.

If the pressing force of both wires is increased considerably at the line of contact with this roll, the pressure generated in the fiber web between the two wires will in some cases completely damage the web, ie if the roll surface is water-impermeable.

Therefore, according to the invention, the roll has a perforated surface so that even when the water volume is very high, the roll surface can receive all the water extruded from the web in the cavities of the surface. It is a good idea to use it here.

The voids on the surface of the roll are made, for example, according to U.S. Pat. It may also be a round hole or miso.

The roll may be a roll-type roll having a wire gauze covered with a wire fabric instead.

The holes in the shell may be through holes, or the holes may be drilled through only approximately half the thickness of the shell.

If the holes pass through the shell, one or more compartments can be placed in the shell of the roll, connected to a suction device so that the holes are emptied by vacuum force.

The roll design (blind hole, through hole, or suction chamber inside the barrel) to be used depends on the speed of the paper machine, the thickness of the fibrous web formed, the freeness of the paper stock, etc. .

Any part or gap between the wire and the roll surface caused by the rotation of the roll that directs air into the gap at or near the point where the web sheathing wire comes into contact with the wet paper guide roll. A so-called blowout phenomenon may occur.

In order to prevent this blowing phenomenon if it is detrimental, it is more preferable in this respect to have a compartment in which the roll is connected to a blowing device.

Providing drainage symmetry may be possible with wet paper guide rolls, in which case other configurations such as overpressure in one compartment on the inside of the roll may be considered. can.

This overpressure makes it possible to carry out a controlled blow at the contact line which increases the drainage in addition to the centrifugal force in the same direction.

As mentioned above, the major portion of dewatering occurs at the web forming rolls.

The importance of this invention is that this fan-shaped body covered with a wire on a web forming roll is transferred to this wet paper guiding roll.JJ
Al in what can be said.

This roll allows better control of the wire tension, which is an important factor affecting the drainage from the web, and also in other similar two-wire paper machines.

Drainage from the web is further continued on the couch roll, primarily by the vacuum in the suction chamber of the couch roll, but to a small extent.

Enlarging the suction sector on the incoming side covered by both wires is possible with a couch roll or, if necessary, with a wet paper guide roll.

It is possible to enlarge the canopy of the suction sector on the run-out side by moving the uppermost wire guide roll, which is close to the couch roll and inside the web sheathing wire, forward in the wire running direction.

If the web-forming roll and couch roll have approximately the same diameter, and if the wet paper guide roll is placed approximately midway between these rolls, both wire courses can be arranged according to the present invention. When changing depending on the roll,
The sectors covered by both wires are increased to the same extent on both rolls.

If it is desired to increase the suction fan cover at the web-forming roll by more than at the couch roll,
The wet paper guide roll must be located in close proximity to the web forming roll.

On the other hand, if it is important in the first place to increase the suction fan of the couch roll, the wet web guiding roll must be placed as close as possible to the couch roll.

The change in the direction of the wire course obtained by the wet web guiding roll can best be expressed as the angle between the direction of the wire and a common tangent drawn outward to the web forming roll and couch roll. .

The most desirable angle depends on the speed of the paper machine, the fiber material used, the basis weight of the paper being produced, etc.

If the purpose of the application of this invention is only to hold the web covering wire and the web carrying wire together closely and at a constant distance between the web forming roll and couch roll, then this angle is approximately 2° to 5°. That's enough.

If it is intended to increase the drainage rate by the centrifugal force generated by the wet paper guide roll, this angle must be considerably larger.

However, it should be noted that the faster the paper is made, the smaller the angle is sufficient than at lower speeds.

In an experimental paper machine constructed by the applicant of the present application in order to test the operation of the two-wire paper machine according to the present invention, a web forming roll (diameter φ=1635 rran) and a couch roll (diameter φ=1300 myn) were used. A wet web guide roll with a diameter φ=800 tran is preferably placed at a point where the tangent line drawn outwards approximately passes through the geometrical axis of the forming guide roll.

This means that the distance between the centers of the suction rolls is 3500 m.
m, which means that the deviation in the common course of the wire caused by the wet paper web guiding roll is about 500 m.

This means that the angle between the tangent and the direction of the wire as it exits the web-forming roll is approximately 12°.

When both wires pass through the web-forming rolls - r, h, the sectors increase by the same amount.

An increase of 13% is achieved when the suction fan corresponds to a 90° corner without a wet paper guide roll.

Place the wet paper guide roll at the same distance from both suction rolls.

So the increase in suction fan sheathing on the couch roll is more similar than on the web-forming roll.

The angle between the incoming and outgoing directions of both wires in the wet paper guide roll is approximately 25 degrees due to the experimental paper machine configuration.

As is known, the drainage rate on couch rolls can be increased by means of pressure rolls.

According to the invention, the topmost guide roll inside the loop of web sheathing wire can act as a suppression roll.

In the production of certain grades of paper, it is undesirable to overpress the web on the couch roll.

In this case, the web sheathing wire is placed in such a way that the web sheathing wire contacts the couch roll only in the suction chamber of the couch roll to such an extent that the formed web separates from the web sheathing wire and remains on the web conveying wire. It is preferable to manage.

The invention will be explained in more detail below with reference to the accompanying drawings.

The two-wire paper machine illustrated in the drawings has two wire loops, a web carrying wire 1 and a web sheathing wire 2.

The web conveying wire can be interpreted as an endless wire on which the paper web 3 rests after the forming process, in which the paper web is separated from the endless wire in a conventional manner in order to introduce the paper web further into the suppression zone of the paper machine. I'll take it up.

Two suction rolls 4 inside the web conveying wire loop
, 5, each suction roll 4, 5 having at least one conventional suction chamber connected to the suction device of the paper machine.

One of these suction rolls at the beginning of the direction of travel of the paper web is the web-forming roll 4.

The web transport wire 1 overlying the web-forming roll 4 and the web sheathing wire 2 adapted to be connected thereto form a throat 12 into which the fiber suspension is fed from the headbox 11 .

There are two different feeding methods.

A method of supplying the fiber suspension to the throat by directing the web covering wire and the web conveying wire to the point where they run together (FIG. 1) or one of the wires.
method (second method) by feeding the fiber suspension preferably to the web sheathing wire earlier than to the other wire.
Figure).

For this latter material delivery method the web sheathing wire 2
A formation plate 110 is provided at the point where the raw material jet is primarily directed.

This method of feeding the stock suspension onto the wire in a two-wire paper machine is similar to that normally used by paper machine operators when feeding the stock onto the horizontal wire of an endless Fourdrinier paper machine. The possibility of adjustments such as adjustment of the speed ratio of the wire and the material jet can be exploited.

Another possibility with asymmetric feed is to direct the jet of fiber suspension towards the web conveying wire at a point facing the forming plate 110 just before the throat 12 ends.

In order to prevent flooding or filling of the throat 12 and to prevent undesired lateral flow in the feedstock suspension fed into the throat, it is preferred that the peripheral speed of the web forming roll 4 is higher than the feedstock jet velocity. .

The throat 120 angle or dimension and the orientation of the throat 12 can be adjusted by changing the position of the wire guide rolls 8a, 7b.

These wire guide rolls 8a, 7b make it possible, in particular to the wire guide roll 7b, to adjust the tension between the web conveying wire 1 and the web sheathing wire 2, so that the tension between the web conveying wire 1 and the web sheathing wire 2 can be adjusted. The pressure generated in the paper web 3 can also be adjusted.

The draining process effectively begins within the throat 12 itself and continues thereafter onto the web forming roll 4.

The water squeezed out of the fiber stock escapes partly outwards due to centrifugal force and partly into the web-forming roll 4 through holes in the roll jacket due to vacuum force.

If dewatering caused by centrifugal forces tends to cause high-speed imbalance or double-sidedness of the paperboard, the web sheathing wire should be selected to have a sufficiently fine mesh;
However, it is first of all possible to provide sufficient suction by having one or more suction chambers corresponding to the internal sector β of the web-forming roll 4 and adjusting the vacuum in the suction chamber according to the draining conditions. can.

After exiting the web forming roll 4, the course of the wire between the web forming roll 4 and couch roll 5 is guided by one or more forming guide rolls 100a.

100b and thus enlarge the fan-shaped body covered by the web conveying wire 1 and the web sheathing wire 2.

A suction chamber is provided and in a lower position i.e. the web forming roll 4.
A wet web guiding roll is shown in FIG. 1 which is placed in close proximity to the web forming roll 4a, thus increasing the sheathing angle at the web forming roll 4a even more than the sheathing angle at the couch roll 5.

If the wet paper web guiding roll 100a is provided with chambers for suction and blowing as in one embodiment of the present invention, it is even more difficult to adjust and define the drainage direction than in the prior art. It becomes possible.

In FIG. 2, a wet paper guide roll 100 without a suction chamber is shown.
b, the wet paper guide roll may have a chamfered surface or may be covered with a woven wire gauze.

The wet web guide roll in FIG. 2 is in an upper position, ie close to the couch roll 5, thereby increasing the covering angle of the couch roll 5.

There are two wet web guide rolls, one of which is located near the web forming roll and the other near the couch roll, so that the sheathing angle is increased simultaneously on both suction rolls.

The web sheathing wire 2 is guided by a wire guide roll 7b adjacent to the web forming roll 4, which can adjust the angle and length of the throat 12 as required. It can be moved freely.

On the couch roll 5, the web sheathing wire 2 overlaps the wire guide roll 7a and the web sheathing wire 2 and the paper web 3 are guided onto the couch roll 5 by the wire guide roll 7a as shown in FIG. 1 in order to increase discharge. It can be pressed against one suction sector.

The position of the wire guide roll 7a on the couch roll 5 can be adjusted, so that in one position the wire guide roll 7a can also act as a pressure roll on the couch roll 5, as shown in FIG.

It is quite important to be able to change the position of the wet paper guide roll for different applications of this invention.

For this purpose, the wire section can be provided with guide bars on both sides, which guide bars are preferably parallel to the common imaginary tangent of the web-forming roll and couch roll.

The support of the wet web guiding roll can be moved along these guide rods to the desired position.

The invention is not limited to the embodiment shown in the drawings, but it can be applied in several variants as described in the description.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the invention, and FIG. 2 is a front view of a slightly different embodiment. In the figure, 1... web conveyance wire, 2... web covering wire, 3... paper web, 4... web forming roll, 5... couch roll, 7a, 7b... wire guide roll, 110... Ground forming plate, 11... Head box, 12... Throat, 100a, 100b
... Wet paper guide rolls, α, β... Suction fan-shaped bodies. :7

Claims (1)

[Scope of Claims] 1. During the web forming process, dewatering from the paper web 3 through the two wires 1, 2 takes place simultaneously in an essential part of the process, one of the two wires a conveying wire 1, the other a web sheathing wire 2, and in the loop formed by the web conveying wire 1 there are two suction rolls, of which the first in the running direction of the paper web is
the suction roll is a web-forming roll 4, the second suction roll is a couch roll 5, the web-forming roll 4 is provided with a fan-shaped body β for dewatering configured in at least one suction chamber; During web formation, the sector β is covered with a web conveying wire 1 and a web covering wire 2, and dewatering is first carried out on the sector β by pressing the web transport wire 1 and the web covering wire 2 together, and the web Before the forming roll 4, the web conveying wire 1 and the web sheathing wire 2 form a throat 12 into which the fiber suspension is fed by the head box 11 of the paper machine, and the web conveying wire 1 and the web sheathing wire 2 are two wires in a paper machine that run together diagonally upward from at least the beginning of the sector β of the web forming roll 4 to the point where the web conveying wire 1 reaches the couch roll 5 in contact with it. In a paper machine, a web conveying wire 1
During the travel of the web-covering wire 2 and web-forming roll 4 together between the web-forming roll 4 and couch roll 5, the path of the two wires 1.2 is such that the wires are not rubbed due to their engagement with stationary members. , by one or several wet paper web guiding rolls 100a, 100b located in the loop of the web sheathing wire 2 and rotating, said wet paper web guiding roll 100a. 100b angulates towards the side of the web transport wire 1 due to the pressure applied to the web transport wire 1 and the web sheathing wire during said journey, so that the wet web guiding rolls 100a, 100b) and the web transport wire 1 A paper machine characterized in that the kneading running portion of the web-forming roll 4 and the web-covering wire 2 is entirely on the side of the loop of the web-covering wire 2 with respect to a plane passing through the center line of the web-forming roll 4 and the couch roll 5. Two-sheet wire paper machine. 2. The wet paper web guiding rolls 100a, 100b are rolls with an open surface, in which the surface structure allows the water to flow towards the axis of the roll. Paper making equipment. 3. A two-sheet wire paper machine as claimed in claim 2, in which the surface of the spaced-surface roll has a plurality of ridges essentially perpendicular to the axis of the roll. 4. A two-sheet wire paper machine according to claim 2, wherein the roll with the spaced surface has a perforated surface. 5. A two-sheet wire paper machine according to claim 2, in which the roll with an open surface is covered with a wire mesh. 6. The two-sheet wire paper machine according to claim 4, wherein the holes in the roll having an open surface are through holes. 7. Rolls with open surfaces are provided with at least one inner chamber, which chamber is connected to an air system, either suction or compression, in order to allow air to flow through the roll holes above said chamber during operation. 2 as set forth in connected claim 6
Sheet wire paper machine. 8. A roll with an open surface is provided with at least one internal chamber, which chamber allows air to flow through the holes in the opposite direction to the other chambers. Two-sheet wire paper machine. 9 directing the jet of suspension between the web conveying wire 1 and the web sheathing wire 2 such that the jet of fiber suspension from the headbox 11 meets the web conveying wire 1 and the web sheathing wire 2 earlier than the other; Throat 12 between 2
A two-wire paper machine according to claim 1, which feeds asymmetrically into the paper. 10. The two-sheet wire paper machine according to claim 1, wherein the web covering wire 2 has a finer mesh than the web conveying wire 1. 11. The two-sheet wire paper machine according to claim 1, wherein the wire guide rolls 7a, 7b for pressing the web sheathing wire 2 against the couch roll 5 are separated from the couch roll. 12. Two-sheet wire paper machine according to any one of claims 1 to 11, in which the web-covering wire 2 is separated from the web by a couch roll 5 at the trailing edge of the first suction chamber. . 13. A two-wire paper machine according to any one of claims 1 to 11, in which at least two suction chambers on the couch roll 5 are covered by a web covering wire 2. 14 Wire guide roll of web sheathing wire 2 closest to couch roll 5? A two-sheet wire paper machine according to claim 1, wherein a and 7b simultaneously act as pressure rolls on one suction chamber. 15. A two-wire paper machine according to claim 9, wherein the first wire encountered after suspension is provided with a formation plate 110 in the point where the material jet is primarily directed. 16. The position of the wet paper web guiding rolls 100a, 100b can be freely adjusted in a direction parallel to the central connection line between the web forming roll 4 and the couch roll 5, and also perpendicular to that direction;
Claim 1, which is provided with such an adjustment reservoir device
The two-sheet wire paper machine described in .