FI115644B - Apparatus for forming a web in a paper machine or the like - Google Patents

Description

115644

Apparatus for forming a web in a papermaking machine or the like 5

The invention relates to apparatus for forming a web in a papermaking machine or the like.

Reference is made to FI 93032, DE 29711629 and DE 10 2947569 in the prior art.

FI 93032 discloses a papermaking strip molder in which a headbox lip jet is directed to a pile between two wires, wherein the first dewatering element is a forming shoe with a curved guide cover. Jul-15 DE 29711629 and DE 2947569 disclose a rotary dewatering element for use on a wire section of a papermaking machine.

Kiteformer structures are known in the art in which the pulp is led from the headbox to the formation between the wire wires and forward between the forming wires.

\ · 20 Kida's state-of-the-art device solution utilizes rotary suction rolls, i.e. former rollers or fixed dewatering lists for water removal and wire guidance.

• »I | * * '· *' The disadvantages of prior art solutions can be considered to be the large diameter dimensions required by the roll solutions 25, whereby the length and height of the machine become * 1 »; · Also high, resulting in high production costs for the machine. In addition, '! 'The headbox lip structures have to be made with the roller diameters so that the free lip jet distance from the headbox between the wires is not too large. There is friction between the wire and the fixed dewatering elements,, ·; 30 which still leads to wire wear. In addition, former rolls are expensive and always require a spare roll.

2 115644 In this application, a molding box which uses roller bearings rotating against the wire is used immediately at the closing point of the kid K instead of the former roller.

By using a forming box according to the invention which comprises rolls arranged to rotate, a good dewatering pressure is achieved on the web. By using rollers, the friction between the wire and the associated dewatering elements is reduced. This results in higher wire tensions, which further leads to an increase in te-10 dewatering efficiency. Wire wear is very low. By using a curved web path in connection with the forming box, due to the centrifugal force, a uniform dewatering of the web through both forming wires is achieved.

By using the low forming box according to the invention, a further 15 boxes are made low in height, thereby reducing the overall height and length of the former relative to conventional ones. This saves on construction costs and material costs for the entire machine. By using the forming box according to the invention, the escape paths for water from the pulp web are small and thus the forming result is good.

20 f ', · By using the forming box according to the invention instead of the conventional dewatering rolls, the structure of the headbox is also influenced so that the headbox'. The cone can be made duller. This will shorten the machine length. Thus, by 1 ... ·, the structural cost 25 is reduced by forming a shorter wire forming part compared to prior art formers.

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The apparatus of the invention for forming a web in a paper machine or the like is characterized by what is claimed.

3, 115644

The invention will now be described with reference to some preferred embodiments of the invention shown in the figures of the accompanying drawings, but which are not intended to be limited thereto.

Figure 1A shows a first preferred embodiment of the invention, i.e. the so-called. vertical gap formers.

Figure IB is a side elevational view of the forming box according to the invention associated with the apparatus of Figure IA.

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Figure 1C is shown in Figure IB formeerauslaatikko of Figure IB as seen from the direction of the arrow K. IB and 1C do not show the wire runs or the mass path run between them.

Figure 2 shows another embodiment of the apparatus according to the invention, i.e. the so-called. vaakakitaformeri.

Figure 3 shows a molding box according to the embodiment of Figure 2: ': a cross-sectional view of the end bearing of the rods.

Fig. 1A shows an apparatus 100 according to the invention for forming a web in a paper machine or the like. FIG. vertical format, • · ·. '! wherein from the headbox 10 a pulp suspension W is introduced into the gap K between the first forming wire 11 ... and the second forming wire 12. The first wire 11 is formed as a wire loop with the wire guiding rollers 13ai, 13a2, 13a3, 13a4 and 13as inside. The second wire loop 12 comprises wire guide rollers 12ai, 12a2, 12a3 and 12a4 within the wire loop. The apparatus 100 according to the invention, which: is a dieformer, comprises, in accordance with the invention, a first dewatering element in the junction area of the wires 11 and 12 (when viewed in the LO direction according to the invention). The forming box 15 comprises circular rolls or rods 16a, 16a2, 16a3, 16a4, 16as and loa. Within the body 200 of the forming box 15 is a suction space Di which is formed to a vacuum of 1 kPa - 40 kPa.

The rollers 16ai ... 16a6 are thus fitted to the suction box body 200 such that the wire loop run at the rollers becomes curved. The center of the wrapping radius is located inside the wire loop of the forming wire 11. Most preferably, there is only one Arc radius, preferably in the range of 500 mm to 2000 mm. More radii of curvature may also be used. Preferably, then, the curvature at the forming box 1510 is formed such that, in the direction of travel of the wire loop, L1 first has a curvature portion R1 that is greater than the subsequent curvature portion R2 of the forming box. The length Δ1 of the forming box 15 is 100 mm to 1000 mm, preferably 100 mm to 400 mm. The radius of curvature R1 is preferably in the range of 1000 mm to 2000 mm and the radius of curvature R2 is preferably in the range of 500 mm to 1500 mm.

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At the forming box 15, water exits the pulp web W from the inside of the forming wires 11 and 12 to the suction box 15 and the wire tension and centrifugal force. . man also in the opposite direction outwards. Thus, the drainage of water from the pulp web W is bidirectional and thus of equal quality to the pulp web W. The forming box 15 can also be divided lengthwise into compartments, ». · · ·. each with individually adjustable vacuum.

• · • 4 * «· • · · •» ». · **. After the forming box 15, Li is located in the direction of travel of the web and the wires.

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inside the wire loop of the forming wire 12, a suction box 17 comprising moldings 18a1a, 18a2, 18a3 and 18a4 between which water is led from the pulp web to the suction box

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17 to the internal vacuum port D2. The figure shows the load * * * loading elements with reference numerals 19ai, 19a2 ... 19a4, which influence the forming lines, ···, ran 11 from the inside of the wire loop in the area of the suction box 17 so that the load Between 18a2, 18a3, 18a4 »and»! 30 races. The load elements 19ai, 19a2 ... can be, for example, compressed air cylinders that can be compressed by compressed air *%.

5, 115644

According to the figure the second forming wire 12 of a wire loop within the suction box after the suction roll 12a2 of 17 (when viewed from the direction of the arrow L? Direction). The suction roll 12ai comprises internal suction boxes 20ai, 20a2 having suction spaces D3 and D4 on the inside.

5 D3 is affected by a different vacuum than D4. The vacuum created in the space D4 is used to hold the pulp track in the wire 12 and to transfer the web run W to the wire 12 only and forward to the transfer suction roll 21 of the press section P, 10 all right. Thus, suction roll 12a2 and suction roll 21 are transfer suction rolls. They thus comprise an inner suction box and a hole in its roll mantle through which the suction is directed through the wire 12 to the web run W.

Figure IB shows formeerauslaatikko end 15 and is shown in Figure 1C 15 15 formeerauslaatikko Figure IB arrow K direction. The forming box 15 extends across the width of the wire 11, 12. The transverse edges J1J2 of the forming box are supported by support members parallel to the direction of the wire movement, preferably moldings 16di, 16d2 ...

16dö. The moldings 16di, 16d2 ... are located under the rollers, rods 16ai, 16a2 ... and support '·' * them and prevent them from bending.

Figure 2 shows a second embodiment of the invention in which the apparatus 100 is formed. · [Occurs in the so-called. vaakakitaformerista. Also in this embodiment, the first wire loop 11 comprises wire guide rolls 13ai, 13a2, 13aa and 13a4. The wire guide rollers 13a ... 13a4 of the wire loop 11 are located inside the looped wire loop. Inside the wire loop in question, there is a box 15, which is similar to the one shown in the previous embodiment, adjacent to the K '7' '. The molding box 15 comprises rollers, rods 16a1, 16a2, 16a3 and '16a4, which are rotatably mounted and abut against the wire 11. Here too «'; the embodiment has rollers 15, 16a2, 16a3 and 16a4 of the forming box 15; 30 so arranged with respect to the direction Li of the web and wires' *, that after the ridge Ki there is first a portion of the web having a radius of curvature R1 6 115644, whose curvature R1 is greater than the curvature R2 of the subsequent web. In this embodiment, a suction box 17 is located inside the wire loop 11 after the forming box 15, the loading members 19ai, 19a2 and 19a3 of which are located within the wire loop formed by the second wire 12 5 and exerting force against the wire 12 from the areas 18a, 18a2 and 18a3. The loading member 19a4 is located before the first strip 18aj as viewed in the direction Li. The second wire loop 12 comprises, on the inside, the wire guide rolls 14ai, 14a2, 14a3, 14a4 and 14as, and on the outside the wire guide rolls 14a4 and 14as in the area. The web W is guided between the wires 11 and 12 in connection with a release simulator 170 located downstream of the wire guide roll 14a2 (relative to the direction of travel Li). The vacuum exerted on the suction box 170 is used to suck the vacuum between the moldings 180ai, 180a2, 180a3 of the suction box 170 into the web W and to hold it in the wire run of the web 12 and to the suction roll 21 of the web W.

By using a forming box 15 in accordance with the invention, which comprises rolls 16a, 16a2 arranged to rotate, a good dewatering pressure is achieved on the web. By using the rolls 16ai, 16a2 ... the friction is lower for the wire and its associated water. : 20 between the stripping elements. This results in higher wire tension, which • leads to further dewatering efficiency. The wear of the wires is »t 1 very low. Using a curved path along the forming box 15. '*; due to centrifugal force, a uniform dewatering of the pulp web through both the forming wire 11 and the forming wire 12 is achieved.

25 * '· <· Using the molding box 15 according to the invention, the puck of the kitter is formed immediately

In addition, in the case of I * '·; * K, the height of the box is low and thus the size of j', · former is smaller than usual. This saves on construction investment costs and material costs for the entire machine. Exit: 30 routes for water from the mass path are short and thus result in a formation of '1 · 1; good.

115644 By using the forming box 15 according to the invention instead of the conventional dewatering rolls, the headbox structure is also affected so that the cone of the headbox can be made blunt. This will shorten the machine length.

Thus, by forming a shorter wire forming member, the structural costs are reduced compared to prior art formers.

Figure 3 is a cross-sectional view of an embodiment of the forming box 15 according to the invention and Figure 2 with its four rollers 16ai, 16a2, 16a3 and 16a4. The rolls or rods 16ai, 16a2, 16a3 and 16a4 that face the wire 11 run are cradled 160ai, 160a2, 160a3, and 160a4 hydrodynamically. The hydrodynamic agent is preferably water. The cradle 160ai comprises pockets 160bi, 16002, 16003 in each hydrodynamic zone of the cradle, which are further connected via intermediate tank space 160d to line 160ci, which further leads via pump 50 to pressure medium tank T. The pressure medium is preferably water.

The space Di is provided with a vacuum by means of a vacuum pump (not shown) and applied at intervals of rolls 160ai, 160a2 ... to the run of the wire 11 and further through the wire 11.: "The mass path W. The space Di may be formed into sections Di ', Di", Di " ', each *, ·' 20 have a different vacuum relative to one another. The vacuum may also be the same at states Dj ', D | ", Di"'. The cradles 160ai, 160a2 ... may extend over the entire length of the bar 16ai, 16a2 ... as in the embodiment of Fig. 2, or may be located only on the bar.

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** "· 16ai, 16a2 at both ends.

* # * »1 i l 25 Paper machine or the like refers to paper, board, and tissue paper machines and paper-drying machines.

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Claims (8)

Apparatus for forming a web in a paper machine or the like, the device (100) comprising a first wire loop formed by a forming wire 5 (11) and a second wire loop formed by a forming wire (12), wherein the mass suspension (W) is led into an inlet carriage (10) into a gap (K) between them and in which device the wire loop (11) comprises wire guide rollers (13ai, 13a2 · ..) and the second forming wire (12) comprises wire guide rollers ( 12at, 12a2 · .. 14ai, 14a2 · ..) that the device comprises as a dewatering element a forming slide (15), underpressure being formed in an inner space (Di) of a body thereof and the forming slide comprising rollers , rods or the like (16ai, 16a2 ...), which are stored to rotate and which come against the forming wire (11), the wire (11) and through this pulp web (W) being ford between the forming wire (11, 12) , is subjected to negative pressure between the rollers (16ai, 16a2 ...), characterized in that the forming load (15) is is the first dewatering element and the forming slide (15) comprises rollers (16ai, 16a2 ...) arranged in the body (200) so that the web race (Li) is curved at the rollers, the forming slide (15) comprising one by means of the rollers (16a). ], 16a2 ...) curvature (Ri) formed on the web (W) at the present mills (16ai, iY: 16a2 ...) and that the radius of curvature lies on the side of the forming wire (11) ♦>: T: 20 the wire loop against which the rollers (16ai, 16a2 ...) press. γ Device according to Claim 1, characterized in that the rollers (16ai, 16a2 ...) are stored in the body (200) of the forming vane (15) hydrodynamically and: the rollers (16ai, 16a2 · ..) lies in mullwaggs (160ai, 160a2 ...). 25 3. Device according to the preceding claim, characterized in that the roller cradle (160) is formed by zone pockets (160bi, 160b2 ...) which have been lubricated: e.g. water. 4. Apparatus according to any of the preceding claims, characterized in that the rollers (16ai, 16a2 ...) extend over the entire width of the web and the rollers are supported in the area between the ends of the rollers with supporting strips (16bi, 16b2.). .), which support strips are supported on the lateral sides (J1, J2) of the suction blanket (15). 5. Device according to any of the preceding claims, characterized in that a vacuum, which is within the range of 1 kPa - 40 kPa, is provided in the inner suction space (Di '; Di', Di '') in the body (200). . Apparatus according to any of the preceding claims, characterized in that, with respect to the running direction (Li) of the web, the forming ladder (15) first has a curvature (Rj) which is within the range 1000 mm - 2000 mm, and then a curvature ( R 2), which is smaller than the bend (R 1) and is in the range of 500 mm - 1500 mm. Apparatus according to any of the preceding claims, characterized in that, after the forming ladder (15) seen in the running direction (Li) of the web (W), a suction cup (17, 170) comprising strips (18ai, 18a2) is provided. , between which the pulp web (W) is subjected to suppression by the forming wire (11) or the forming wire (12). 8. Apparatus according to any of the preceding claims, characterized in that in the area between the strips (18ai, 18a2) is affected on the opposite side of the race; ': (11, W, 12) in relation to the suction vane (17) with load elements (19ai, 19a2): <t: for example compressed air loaded elements for example compressed air cylinders. *> r * 1