US 3746613 A
Description (OCR text may contain errors)
July 17, 1973' VAUHKONEN 3,746,613
' TWIN WIRE, PAPER MAKING MACHINL wmmhm Tm;
, WIRES TRAVEL. 'IN AN Am; Filed Feb. 11', 1971 2 Shouts-Sheet 1 FIG] INVENTOR: E. Vauhmonen July 17, 1973 E. VAUH NEN 3,746,613
I TWIN WIRE PAPER MAKING CHI WHERBIN THE WIRES TRAVEL IN AN C Filed Feb. 11, 1971 v 2 Sheets-Sheet 2 was INVENTOR: E- VQU/7KOI7QD ATTOR-NEJS United States Patent 3,746,613 TWIN WIRE PAPER MAKING MACHINE WHEREIN THE WIRES TRAVEL IN AN ARC Esko Vauhkonen, Syrjalankatu 9 A 195, Jyvaskyla, Finland Filed Feb. 11, 1971, Ser. No. 114,639 Int. Cl. D21f 1/00 U.S. Cl. 162--301 6 Claims ABSTRACT OF THE DISCLOSURE A paper making machine has a forming section provided with two endless wires forming a narrowing zone for the formation of paper web from pulp slurry fed into the zone. Parts of wires facing each other are urged against the paper Web located between them by the use of table rolls. The invention is particularly characterized by the arrangement of the table rolls within one of the endless wire loops such that a line connecting their axes forms an imaginary arc of a cylindrical surface. Other table rolls which are located within the second closed wire loop and between the first mentioned table rolls in such manner that their periphery penetrates by a given distance into the space beyond the outer tangential plane of the first-mentioned table rolls to produce a serpentinelike path of travel for the paper web in addition to moving in an arc.
This invention relates to a wire section of a paper making machine. The wire section is of the type provided with two endless wires which form a narrowing webforming zone into which the pulp slurry is conducted. After this zone parts of wires pointing toward each other are pressed against the paper web located between them.
In prior art, paper webs were usually formed on socalled Fourdrinier machines. In these machines, the slurry flows through the slice of the headbox onto a moving, endless wire. Thus water escapes only in one direction through the wire. This has the drawback that the completed paper will be asymmetric in its structure. When the machine operates at high speed, the adjacent air interferes harmfully with the free surface of the pulp web which is being formed. As a result, the so-called paper formation of the product is impaired, and this is an obstacle to attempts to increase the speeds of machines. In attempts to eliminate these drawbacks, machines have been provided in which the paper web is formed between two forming surfaces. These types of equipment are of two principal kinds. According to one type the paper web is formed between two wires or between a wire and a felt. The other principal type comprises a wire and a cylinder. All the wire sections with two wires known in prior art have many drawbacks. It has been difficult in them to make long enough that distance over which the wires are pressed against each other. In addition, dewatering of the paper web has taken place only by pressure exerted by the wires. It has not been possible to adjust the tension of the wires to cause sufiicient pressure of the wires against each other.
An object of the present invention is to provide a wire section of the described type which does not have the drawbacks of prior art constructions.
Other objects of the present invention will become apparent in the course of the following specification.
In the accomplishment of the objectives of the present invention it was found desirable to arrange the table rolls inside one closed wire loop which guide the wires and the paper Web between them to form an arc and place the table rolls outside the wire loop and inside a second closed wire loop between each of the abovementioned table rolls so that their periphery projects a given distance inside the common external tangent plane of the two table rolls. The surface on which the axes of the table rolls inside the one closed wire loop is located is at least approximately a part of an imaginary cylindrical surface. The cylindrical surface may be located at least substantially in its entirety on one side of the vertical plane which extends through the slurry feeding point, but it may also be at least substantially located above or below the horizontal plane passing through the pulp feed aperture. Furthermore, requisite save-alls and water deflector plates are located inside both closed wire loops. Since in a wire section in accordance with the present invention the table rolls within one wire loop have been placed so as to form an arc, the wire runs can be made shorter than those in prior machines and the wires can be made to urge against each other over the entire stretch along which dewatering takes place. The pressure between the wires can be substantially altered by increasing the tension of the wires, because each table roll located inside one of the two wire loops protrudes into the space beyond the external tangential plane upon two table rolls enclosed within the other loop. As a result of the curved path which the wires follow, there is also created in this region a centrifugal force effect, which adds to the dewatering capacity. Since two adjacent table rolls on different sides of the wire path always rotate in the same direction, dewatering through the wire run will alternate all the time, whereby a paper web of uniform quality is produced.
The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings showng by way of example only, preferred embodiments of the inventive idea.
In the drawings:
FIG. 1 is a diagrammatic elevational view of a wire section of the present invention.
FIG. 2 is similar to FIG. 1 but illustrates a different embodiment.
FIG. 3 is similar to FIGS. 1 and 2 but illustrates yet another embodiment.
Similar parts are indicated by the same numerals throughout the drawings.
The drawings show wire sections provided with two wires 1 and 2 which form endless loops and which over a part of their path have been arranged to be urged against each other. One of the wires, 1, forms the inner loop 3 and the other wire, 2 forms the outer loop 4. The course of the wires is guided by guiding rolls within the loops, which have been indicated by numerals 5a in the inner loop 3 and by numerals 5b in the outer loop. The Wires are further guided by breast rolls 6a and 6b, by forward rolls 7a and 7b, by tension rolls 8a and 8b, and in the part of the loops where the wires 1 and 2 are urged against each other, by table rolls 9a and 9b. The breast rolls 6a and 6b are separated by a certain distance so that between the wires 1 and 2 which these rolls guide onto the table rolls 9a and 9b there is formed a narrowing paper Webforming zone 10, into which pulp slurry is fed from the headbox H in the direction of the arrow A. In the forming zone 10 there are forming tables 11a and 11b, which support the wires and through which part of the water in the pulp slurry is already drained.
From the paper web-forming zone 10, the wires 1 and 2 are delivered for guidance by the table rolls 9a and 9b. In all the embodiments, every second table roll 9b is located within the outer loop 4 and every second table roll 9a is located within the inner loop 3. The axes of the table rolls 9a within the inner loop 3 have been placed so as to form an arc indicated by broken line X.
In accordance with the embodiment shown in FIG. 1 the table rolls 9a within the inner loop have been placed to form an arc in such manner that the part of an imaginary cylindrical surface which they constitute lies in its entirety on the left side of the vertical plane passing through the slurry feeding point.
In the embodiment shown in FIG. 2, the table rolls 9a constitute a part of a cylindrical surface lying below the horizontal plane passing through the slurry feeding aperture.
On the other hand, according to the embodiment of FIG. 3, the table rolls 9a are located above this horizontal plane. The table rolls 9b within the outer loop 4 are so placed that each one of them is located between two table rolls 9a found within the inner loop 3, so that the periphery of the table roll 9b within the outer loop penetrates a given distance into the space beyond the common external tangential plane of the two table rolls 9a within the inner loop 3, most appropriately so that this penetration increases in the direction from the end at which slurry is introduced towards the end at which the paper web emerges. At the ultimate end of the wire part, there are suction boxes 12. Within the inner and outer wire loops there are requisite save-alls 13a and 13b and water deflector plates 14a, 14b. All requisite save-alls and water deflectors have not been shown for the reason that the present invention does not concern them.
However, small save-alls 15 under the table rolls within the wire loop have been shown in FIG. 2.
When the table rolls have been placed in the described manner, water is drained alternately to either side of the wire section. Consequently, uniform structure of the paper web is achieved. Since the table rolls have been placed so as to form an arc, centrifugal force also assists the dewatering action in the wire section.
The invention is by no means limited to the described embodiments, but modifications within the scope of the claims are possible. For example, the table roll within the outer loop need not necessarily penetrate into the space beyond the common external tangent plane of two adjacent table rolls in the inner loop; it may instead tangentially touch said tangent plane.
1. In a paper making machine, a wire section comprising two closed wire loops, a paper web forming zone enclosed by said wire loops and having a narrowing section with an aperture adapted to receive pulp slurry, means having an aperture supplying pulp slurry into the narrowing section of said forming zone, table rolls guiding the wires and the paper web and comprising table rolls arranged to form an arc and located within one closed wire loop and other table rolls arranged to form an arc and located outside said one closed wire loop and inside the other closed wire loop, the arcs being located close to each other with the second-mentioned table rolls being located be tween the first-mentioned table rolls and so that the peripheries of the second-mentioned rolls extend through and beyond a tangential plane passing through the peripheries of two adjacent first-mentioned table rolls.
2. A wire section in accordance with claim 1, wherein the axes of the first-mentioned table rolls are located substantially upon a common imaginary cylindrical surface.
3. A wire section in accordance with claim 2, wherein said imaginary cylindrical surface extends substantially in its entirety upon one side of a vertical plane passing through said pulp slurry supplying aperture.
4. A wire section in accordance with claim 2, wherein said imaginary cylindrical surface extends substantially in its entirety below a horizontal plane passing through said pulp slurry supplying aperture.
5. A wire section in accordance with claim 2, wherein said imaginary cylindrical surface extends substantially in its entirety above a horizontal plane passing through said pulp slurry supplying aperture.
6. A wire section in accordance with claim 1, further having an outlet for the paper web spaced from said means, the extension of the peripheries of the second-mentioned rolls beyond said tangential plane increasing in the direction toward said outlet.
References Cited UNITED STATES PATENTS 3,262,841 7/1966 Embry 162-203 X 3,578,561 5/1971 McCarrick et al 162352 1,241,905 10/1917 Behr 1'62318 3,597,315 8/1971 Notbohn et a1 162-303 3,565,757 2/1971 Jordansson 162-203 X S. LEON BASHORE, Primary Examiner R. H. TUSHIN, Assistant Examiner U.S. Cl. X.R. 162203, 303