FI120796B - Adjusting the suction box distance from the back roll - Google Patents

Description

Adjusting the suction box spacing from the back roller Regiering av en suglädas avständ frän en motvals TECHNICAL FIELD 5

The invention relates to a method according to the preamble of claim 1.

The invention further relates to the waste test according to the preamble of claim 4.

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As used herein, a web making machine refers to a paper, board, tissue, or pulp drying machine.

BACKGROUND ART

In web making machines, suction boxes are used at many points to remove water from the web and / or transfer the web from one web to another.

*: ··· EP 912798 discloses a *: **: 20 suction box for use in a paper or board machine. The suction box has movable moldings which, at least when the suction box is used, form a curved surface. The strips are placed in U-shaped clips • *;, · · with load members to load the strips against the wire.

EP 0967323 discloses a wire machine section of a papermaking machine in which a support member, i.e. a first foil strip having a sliding surface, is provided at the beginning of the two-wire-25 section when the outer wire and the inner wire are removed from the surface of the former roll. The following foil surface forms an angle of 1-5 degrees with the outer wire, whereby a vacuum zone is formed between the foil surface, the wire and the outer wire due to the movement of the wire.

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Figure 3 of the publication shows a suction shoe having a hollow inner portion connected to a sub-30 pressure source. The suction shoe is supported by a pivot point at its rear edge for a fixed support • Φ ·: * · *; the front and the leading edge are supported by a pressure hose on said fixed support. The angle of the suction shoe 2 to the outer wire can thus be adjusted by means of the aforementioned pressure hose. In this embodiment, the sliding surface has openings and the sliding surface is connected to a vacuum source. The problem presented in this publication is the instantaneous separation of the wire belts from the former roll after the former roll in the kitformer, which causes problems with the forming of the web. A solution to the problem is presented in the publication, wherein the wire is loaded with a device having a sliding surface touching the outer wire belt and, following the wire running direction, * a subsequent release surface which creates a vacuum. In the embodiment of Fig. 3, this vacuum can be enhanced by forming a sliding surface as a suction shoe and connecting it to a sub-10 pressure source.

The lid of the prior art suction boxes has a curvature of the same or slightly larger radius than the outer surface of the roll shell facing the suction box. In this way, a constant gap is achieved between the outer surface of the suction box cover and the outer surface of the counter roll cover.

Higher negative pressure and hence better dewatering and dry matter content of the paper after the former are obtained by reducing the distance between the suction box lid outer surface and the ·: ·· * outer surface of the roll shell. In the distance, however, there is a limit of *: **: 20, whereby the suction box no longer receives sufficient air with the web and tissues. In this case, the suction box starts to steal air at its edges, which degrades the paper quality and the paper machine's runnability.

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C '* SUMMARY OF THE INVENTION

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The solution according to the invention allows the outer surface of the suction box lid to be adjusted at a distance from the outer surface of the suction box cover so that a smooth or wedge-shaped surface is formed between the outer surface of the suction box lid and the outer surface of the roll shell. · * ·!: Slot extending towards the inlet or outlet edge of the suction box.

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The main features of the method according to the invention are set forth in the characterizing part of claim 1.

The main features of the stiffener according to the invention are set forth in the characterizing part of claim 4.

Other features of the invention are set forth in the dependent claims.

In the solution of the invention, a pivot point is rotated around the outlet edge of the suction box, around which the suction box can be pivoted, whereby the distance of the outer surface of the suction box cover from the outer surface of the The distance between the suction box leaving edge is always constant from the outer surface of the counter roll sheath. With this arrangement, the air gap is adjusted as small as possible at the leaving edge of the suction box lid 15, which results in a higher vacuum in the suction box and a better dry solids content of the paper. The required amount of air is led to the suction box by the larger air gap at the inlet edge of the suction box.

*: **: 20 At start-up, the air gap is kept constant over the entire suction box, so that the web • · ...

· / ·! transfer to the outside of the suction box lid is easy. Thereafter, the suction cup • *;, · · is rotated around a pivot point on the suction edge of the suction box lid, thereby opening a gap in the inlet edge of the suction box lid.

With a wedge-shaped air gap, the vacuum box achieves a higher vacuum * ·: ** and thus a higher dry matter content of the paper after the former compared to the flat-bottomed suction box. Also, paper quality and paper machine runnability are ·· * • *, · easier to control.

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: ** ·; 30 BRIEF DESCRIPTION OF THE FIGURES

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Fig. 1 is a schematic cross-sectional view of the machine of the suction box and associated counter roll.

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Fig. 2 is a schematic machine sectional view of the suction box shown in Fig. 15 and the associated return roll.

Figure 3 is an enlarged view of point B of Figure 2.

Fig. 4 is an enlarged view of the position A of Fig. 2 at start-up.

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Fig. 5 is an enlarged view of point A of Fig. 2 in a driving situation.

Fig. 6 is an enlarged view of the leaving edge of the suction box lid.

Fig. 7 is a schematic machine sectional view of the suction box shown in Fig. 1 and the associated counter roll at the bearing housings of the counter roll.

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·: ·· * 20 DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 1 is a schematic cross-sectional view of the machine from the suction box 100 and the counter roll 10. The counter roll 10 comprises a sheath 11, at the ends of which the shaft pins 12a, 12b are attached. The shaft pins 12a, 12b, in turn, are rotatably supported 25 on bearings in the bearing housings 13a, 13b and the bearing housings 13a, 13b are supported on the machine frame structures, the box 100 being supported at its ends by screws. ·· * with hinges 20a, 20b to bearing housings 13a, 13b of the counter roll 10. The screw mechanisms 20a, · · · 2 *. · 20b adjust the distance of the suction box 100 from the outer surface of the diaper 11 of the reel 10 to a value of.

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Fig. 2 is a schematic machine sectional view of the suction box 100 shown in Fig. 1 and associated counter roll 10. The suction box 100 preferably has a curved rib 111 formed by a rib 110 having an inlet edge 110a and a leaving edge 110b. Between the moldings 111, there are slots 112 through which the vacuum P acting on the suction cup 100 can be applied through the lid 110 of the suction box 100. The web W is guided in the support of the wire 21 into the space between the web 31 extending on the outer surface of the sheath 11 of the counter roll 10 and the outer surface 110 of the suction box 100. A knuckle 120 is provided adjacent the leaving edge 110b of the lid 110 of the suction box 100. The back roll 10 is preferably a suction roll and the web W is moved from the fabric 21 10 to the surface of the fabric 31 under vacuum and further forward in the webmaking process.

Figure 3 is an enlarged view of position B of Figure 2. The figure shows the leaving edge 110b of the lid 110 of the suction box 100, along which a pivot point 15 120 is imaged. The box 100 is thus pivotable about the pivot point 120 at the leaving edge 110b of the lid 110.

Fig. 4 is an enlarged view of A in Fig. 2 at start-up and ·: · *: Fig. 5 is an enlarged view of A in Fig. 2 in a running situation. In the start-up *: **: 20, the lid 110 of the suction box 100 is equidistant from the outer surface of the cover 11 of the counter roll 10. At start-up, the distance of the outer surface of the cover 110 of the suction box 100 from the outer surface of the sheath 11 of the counter roll 10 is SI and the running distance stated is: S2 measured at the inlet edge 110a of the suction box 100. Said driving situation distance S2 is greater than the starting situation distance S1 and is achieved by rotating suction box 100 about the suction point 120 of suction box lid 110 at leaving edge 110b.

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By tracking the pivot point 120 at the leaving edge 110b of the suction box 100 lid 110b, the suction box 100 can be pivoted in a driving situation so that a wedge-shaped formation is formed between the suction box 100 30 lid 110 and the outer surface 11 of the diaphragm 10, ··· I * · ': A gap narrowing towards the leaving edge 110b of the suction box 100.

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Fig. 6 is an enlarged view of the leaving edge 110b of the lid 110 of the suction box 100. In this embodiment, the last list 111 of the leaving edge 110b of the lid 110 of the suction box 100 is to be loaded, e.g., by a pressure hose lila, whereby the air leaks of the leaving edge 110b of the suction box 100 can be completely prevented. The figure also shows the holes 14 in the shell 11 of the counter roll 10 through which the negative pressure in the counter roll affects the web. If necessary, overpressure can also be applied to the backing roll, whereupon the web W can be reliably followed by the wire 21 and further guided to the pulper below.

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Figure 7 is a schematic machine sectional view of the suction box 100 shown in Figure 1 and associated counter roll 10 at one bearing housing 12a of counter roll 10. The suction box 100 is supported on the bearing washers 13a of the counter roll 10 by a screw mechanism 20a on both the operating and maintenance sides. The screw mechanism 15a can be used to adjust the distance of the suction box 100 from the counter roll 10 and the front and / or trailing edge of the suction box 100 to the counter roll 10. The screw mechanism 20a can be any screw mechanism 20a known to those skilled in the art. The screw mechanism 20a can also be replaced by a solution based, for example, on a hydraulic: •: ·: cylinder-piston solution.

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In the embodiment shown in the figures, the lid 110 and / or the lid 110 of the suction box 100 • * ·. · | The moldings 111 on 110 form a curved pathway against which the wire 21 will be.

At least two moldings 111 are required on the lid 110 of the suction box 100, but there are preferably more moldings 111 ·· · ... ·. The strips 111 may be fixed or adjustable radially. For example, in the situation where the rails 111 are adjustable radially * · * · ϊ * · the shape of the path they create may vary between driving situations and between driving and stopping.

The above are only some preferred embodiments of the invention and are apparent to the person skilled in the art: * ♦ It will be apparent to one of ordinary skill in the art that numerous modifications may be made. claims.

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Claims (6)

A method of regulating the distance from the outer surface of the manifold by a counter roll (11) to a suction cup (100) in a web forming machine, the suction cup (100) comprising a cap (110) having an inlet edge (110a) and an outlet edge. (110b), which are disposed against the outer surface of the male end of the counter roll (1), at a distance from this in such a manner that between the outer surface of the counter roll (1) and the outer surface of the suction lid (100) lid ( 110), a passage is formed, characterized in that in connection with the outlet edge (110b) of the cover (110) of the suction cup (110), a hinge point (120) is arranged around which the suction cup (100) can be turned so that the passage between the outer surface of the cover (110) of the suction cup (100) and the outer surface of the cover (11) of the counter roll (10) can be formed into a wedge-shaped passage which tapered against the outlet edge (110b) of the cover (110) of the suction cup (100). ICE 2. A method according to claim 1, characterized in that the shape of the outer surface of the cover (110) of the suction cup (100) is arranged so that said passage becomes smooth. arcuate. • · • · · · · ·. . Method according to Claim 1 or 2, characterized in that a loadable strip in * · is provided at the outlet (M) of the (110b) of the cover (110) of the suction cup (100). (11a), whereby air leakage at the outlet edge (110b) is completely prevented. • · · · ♦ An arrangement for controlling the distance from the outer surface of the manifold (11) by a counter roll (10) to a suction cup (100) in a web forming machine, the suction cup (100) comprising a cover (110) with an inlet edge (110a). and an outlet edge (110b), which may · position itself toward the outer surface of the male end of the counter roll (1), at a distance from the · ···. in such a manner that a passage is formed between the outer surface of the casing of the counter roll (1) and the outer surface of the cover (110) of the suction cup (100). that, in connection with the outlet edge (110b) of the cover (110) of the suction cup (110), a guide point (120) is arranged around which the suction cup (100) is reversible so that the passage between the outer surface of the suction cup (100) ) cover (110) and the outer surface of the casing (11) of the counter roll (10) can be formed into a wedge-shaped passage, which tapers to the outlet edge (11 Ob) of the cover (110) of the suction cup (100). 5. Arrangement according to claim 4, characterized in that the shape of the outer surface of the cover (110) of the suction cup (100) is such that said passage is evenly shaped. Arrangement according to claim 5 or 6, characterized in that a strip (purple) arranged at the outlet edge (110b) of the cover (110) of the suction cup (100) is loadable, whereby air leakage at the outlet edge (110b) is completely prevented. . a · a · a · a · a · a · a · a · a · a · a · a · a · a · a · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·