EP2017384B1 - Inclined screen former of a machine for producing a sheet of fibrous material from at least one fibrous suspension - Google Patents

Description

The invention relates to a Schrägsiebformer a machine for producing a fibrous web, according to the preamble of claim 1.

Such Schrägsiebformer is from the US-A-4081321 known.

Another Schrägsiebformer is for example from the German patent application DE 10 2004 047 518 A1 and is manufactured and sold by the applicant under the name "HydroFormer". It is used primarily for the production of long fiber papers and wet nonwovens, this type of sheet formation fibers and fiber mixtures of various materials are used with a length of 1 to 40 mm.

The dewatering width of this Schrägsiebformers, also called Formationsbreite in professional circles, is generally determined by the clear box width of the headbox. This clear box width essentially determines the width of the fibrous web to be produced and is a constructive basic feature of the headbox, which can not be changed easily. Thus, the dewatering width and the width of the fibrous web to be produced of the Schrägsiebformers shown already set more or less unchangeable in its design in broad strokes.

It is therefore an object of the invention to develop a skew former of the type mentioned in such a way that the width of the fibrous web to be produced can be changed in particular during its operation and in particular in the larger width ranges. This possibility of change should also be subject to simple handling and be characterized by only minor additional costs in acquisition and operation.

This object is achieved according to the invention in a Schrägsiebformer of the type mentioned by the characterizing features of claim 1.

The object of the invention is hereby completely solved.

By providing these slidable intermediate strips the possibility is created to change the suction slots formed between the drainage strips of the suction box geometrically, so to reduce in size or increase in size. Thus, therefore, the drainage width of the Schrägsiebformers is changed over the Saugzonen width.

In experiments carried out it has been shown that the width of the fibrous web to be produced is significantly determined by the dewatering width of the Schrägsiebformers. If the dewatering width is now reduced or increased independently of the clear box width of the headbox, the width of the fibrous web to be produced also changes correspondingly due to generated transverse flows in the at least one pulp suspension applied to the wire as a result of the light suction of the suction box. The at least one pulp suspension applied to the sieve therefore experiences a reduction or enlargement with regard to its applied width, which is ultimately fixed on account of the dehydration and the at least one pulp suspension. And this fixed width of at least one applied to the screen pulp suspension ultimately represents the width of the fibrous web to be produced.

By the illustrated change in the drainage width of the Schrägsiebformers can thus be changed in a simple manner, so with ease of use, the width of the fibrous web to be produced, especially during operation of the Schrägsiebformers and in particular in the larger width ranges. Moreover, this possibility of change is characterized by only minor additional costs in acquisition and operation of the Schrägsiebformers.

Thus, the change in the width of the fibrous web to be produced can also be performed effectively and reliably, in a preferred embodiment, several, preferably all suction slots of the suction box in the two edge zones of the screen, each provided with a sliding intermediate strip.

In this case, arranged on one side of the suction box intermediate strips can be individually, in groups or together displaced. These possibilities presented allow a locally individual, fast, precise and effective change of the drainage width of the Schrägsiebformers and thus the width of the fibrous web to be produced. With a common displacement of the one-side arranged intermediate strips, the format of the fibrous web to be produced can be changed directly and quickly. On the other hand, in the case of an individual displacement of the intermediate strips arranged on one side, the basis weight in the corresponding edge region of the fibrous web to be produced can be influenced.

The individual intermediate strip is displaceable by means of a valve plate acted upon by at least one actuator. This allows a fast and precise shift with excellent repeatability.

Furthermore, at least one cover plate is arranged in the respective peripheral region of the suction box, which supports the slide plate in a planar manner. This cover plate gives the system a sufficient degree of stability and ensures a continuous reliability in terms of possible shifts.

The cover plate also carries the actuator on the underside, so that it is on the one hand safely mounted and on the other hand sufficiently protected against potentially harmful environmental influences. Taking into account practical aspects, the actuator comprises a spindle drive which acts on the slide plate via at least one spindle drive. Thus, even with longer suction boxes a precise and effective change of the drainage width of the Schrägsiebformers can be achieved. In principle, the actuator can be an electrical, an electromechanical, a magnetic, a pneumatic and / or a hydraulic drive.

So that the dewatering width of the Schrägsiebformers can be changed in current dimensions taking into account current and future requirements, the intermediate strip preferably has a displacement in the range of 1 to 500 mm, preferably from 25 to 200 mm, in particular from 50 to 150 mm. In addition, the intermediate strip and its two adjacent drainage strips ideally have an overlap in the range of 100 to 400 mm, preferably from 125 to 300 mm, in particular from 50 to 150 mm, so that a sufficiently stable and sealing guidance of the individual intermediate strips can be ensured ,

Further, the suction zone width of the suction box is preferably in the range of 1,000 to 11,000 mm, preferably in the range of 1,800 to 10,000 mm, especially 3,000 to 8,000. These areas can easily meet current and future requirements.

Thus, the sieve can be performed as gently and wear-resistant on the suction box, it is in the direction of the wire directly upstream of the sieve plate facing arranged with a preferably curved guide surface.

In consideration of practical aspects, the head box may be configured as a multi-layer headbox, preferably with a sectioned consistency control for at least one layer of the multi-layer headbox is provided. Alternatively or additionally, at least two headboxes may be arranged on the inclined wire former, wherein preferably a sectioned fabric density control is provided for at least one layer of a headbox.

Further features and advantages of the invention will become apparent from the dependent claims and the following description of preferred embodiments with reference to the drawings.

Figur 1

eine schematische Seitenansicht einer vorteilhaften Ausführungsform eines erfindungsgemäßen Schrägsiebformers einer Maschine zur Herstellung einer Faserstoffbahn;

Figur 2

eine Draufsicht auf den Saugkasten eines erfindungsgemäßen Schrägsiebformers der Figur 1;

Figur 3

eine Längsschnittdarstellung des Saugkastens des erfindungsgemäßen Schrägsiebformers der Figur 2; und

Figur 4

eine randseitige und oberseitige Schnittdarstellung des Saugkastens des erfindungsgemäßen Schrägsiebformers der Figur 2 gemäß der Schnittlinie X-X.

Show it

FIG. 1

a schematic side view of an advantageous embodiment of a Schrägsiebformers invention a machine for producing a fibrous web;

FIG. 2

a plan view of the suction box of a Schrägsiebformers invention FIG. 1 ;

FIG. 3

a longitudinal sectional view of the suction box of the Schrägsiebformers invention FIG. 2 ; and

FIG. 4

an edge-side and top-side sectional view of the suction box of the Schrägsiebformers invention FIG. 2 according to the section line XX.

The FIG. 1 shows a schematic side view of a Schrägsiebformers 1 of a machine for producing a fibrous web 2, in particular a long fiber paper or wet nonwoven web, from at least one pulp suspension. 3

The Schrägsiebformer 1 has a screen 4, which runs over a peripheral region 6 of a breast roll 5 and then in the wire direction S (arrow) at least in sections at an angle α obliquely to the horizontal H, wherein the angle α has a value in the range of 0 ° to 45 ° can assume. In the present embodiment, the angle α is about 20 °. In this oblique section 7 of the strainer 4 brings a headbox 8, the pulp suspension 3 on the top of the sieve 4 and on the underside, a dewatering element 9 is arranged for dewatering the applied to the sieve 4 pulp suspension 3.

The headbox 8 is arranged such that it applies in the region of the dewatering element 9, the preferably complete pulp suspension 3 on the screen 4, the front wall 8.1 of the headbox 8 thus ends in the end region of the dewatering element 9 and thus forms an outlet gap A. Alternatively, the drainage element 9 could also go beyond the application area of the headbox 8.

The Indian FIG. 1 illustrated headbox 8 is a conventional headbox of known design and proven operation. It may be formed in a further embodiment as a multi-layer casserole, preferably a sectioned consistency control (dilution water technology) is provided for at least one layer of this multi-layer casserole. Or at least two headboxes may be arranged in the area of the inclined wire former, wherein preferably a sectioned fabric density control ("diluting water technology") is provided for at least one headbox. Such a sectioned consistency control is, for example, in the German patent DE 40 19 593 C2 shown and described.

The illustrated drainage element 9 is designed as a suction box 10 known to those skilled in the art, which is open to the wire 4, to exert a suction effect on the wire 4 and the at least one pulp suspension 3 applied on the upper side of the wire 4. Furthermore, the suction box 10 a plurality of the sieve 4 touching and spaced apart drainage strips 11, which extend transversely to the wire direction S (arrow) and define a plurality of suction slots 12.

The suction box 10 also has, for example, five suction zones Z ₁ to Z ₅ in the direction of the wire run S (arrow). The number of suction zones of the suction box 10 as a rule moves between four and eight suction zones, preferably between five and six suction zones. The suction zones Z ₁ to Z _{5 of} the suction box 10 shown can be acted upon by at least two different subpressures U ₁ , U ₂ generated by two separate vacuum sources 13. ₁ , 13. ₂ for the zones Z ₁ , Z ₂ , Z ₃ and Z ₄ , Z ₅ become. The vacuum sources 13.1, 13.2 may be designed, for example, as preferably controllable / controllable vacuum pumps. Of course, only a negative pressure source may be present, which preferably engages in the lower region of the suction box. The drawn in the suction box 10 from the pulp suspension 3 white water 14 is by means of a white water drain 15 off and the known white water circuit fed. Also, instead of a single suction box 10 more consecutively arranged suction boxes may be present.

At the end of the oblique stretch section 7, the wire 4 together with the underlying fibrous web 2 is guided over a guide roller 16 before the fibrous web 2 is removed in a known manner from the wire 4 and fed to other machine sections. The screen 4 is then returned to the breast roll 5 via a plurality of guide rollers 17. During this recirculation, the screen 4 is usually cleaned by means of a known cleaning device.

Furthermore, in an embodiment not shown at least one of the screen 4 leading element, such as the breast roll 5, be connected to at least one acting on him shaker to the oscillating movement transverse to the wire direction S (arrow). Such a shaking plant is basically the known prior art, is for example from the German patent application DE 197 04 730 A1 or from the German Utility Model G 93 17 640 U1 and is manufactured and distributed by the applicant under the name "DuoShake".

The suction slots 12 of the suction box 10 are now in the two edge zones R _R , R _{L of} the sieve 4 - seen in the wire direction S (arrow) - each provided with a sliding intermediate strip 18, which sealingly fitted between the two adjacent drainage strips 11, wherein the intermediate strips 18 of a suction slot 12 together determine a suction zone width B _Z , which is smaller than the width B _{4 of} the sieve 4 (see. FIG. 2 ). The respective intermediate strip 18 thus has, at least in regions, along its height, the opposite contour of the drainage strip 11 which is in each case adjacent to one another.

The intermediate strips 18 arranged on one side of the suction box 10 in its peripheral region 10R, 10L are individually displaceable, groupwise or jointly displaceable. Here, the single intermediate strip 18 by means of a acted upon by at least one actuator 20 slide plate 19 is displaceable (see. FIG. 2 ).

Furthermore, the suction box 10 in the wire direction S (arrow) directly upstream of a sieve 4 leading plate coating 21 with a preferably curved guide surface F21 upstream. The length L21 of the guide surface F21 in the wire running direction S (arrow) is in a range of 150 to 400 mm, preferably 200 to 350 mm. The plate covering 21 is externally fixedly mounted on the respective cover plate 22 of the suction box 10, for example by means of several screw 23 (see. FIG. 3 ).

The FIG. 2 shows a plan view of the suction box 10 of a Schrägsiebformers invention 1. For the sake of clarity, the top view is provided with a section.

The suction slots 12 of the suction box 10 are, as already stated, in the two edge zones R _R , R _{L of} the screen 4 - seen in the wire direction S (arrow) - each provided with a sliding intermediate strip 18, which fitted sealingly between the two adjacent drainage strips 11 are, wherein the intermediate strips 18 of a suction slot 12 together a suction zone width B _Z which is smaller than the width B _{4 of} the wire 4. The suction zone width B _{Z of} the suction box 10 is in the range of 1,000 to 11,000 mm, preferably in the range of 1,800 to 10,000 mm, in particular from 3,000 to 8,000. There are, again for clarity, only the in the beginning and end of the suction box 10 - seen in the wire direction (S) - mounted intermediate strips 18 shown.

The arranged on one side of the suction box 10 intermediate strips 18 are jointly displaceable in the present embodiment, but they can also be individually or in groups displaced. The common displacement takes place indirectly, by means of a valve plate acted upon by an actuator 20. The individual actuator 20 comprises in the present embodiment a spindle drive 20.1, which acts on the two slide mechanisms 20.21, 20.22 the slide plate 19. The individual components 20.1, 20.21, 20.22 are connected to each other via drive shafts 20.31, 20.32.

Further, in the respective edge region 10 _R, 10 _{L of} the suction box 10, a contoured cover plate 22 is arranged, which supports the associated slide plate 19 flat. The respective cover plate 22 is provided with corresponding recesses 24 to allow the loading of the mounted slide plate 19 by the spindle gear 20.21, 20.22.

The suction box 10 is in the wire direction S (arrow) also directly upstream of a sieve 4 leading plate coating 21 with a preferably curved guide surface F ₂₁ upstream. The length L _{21 of} the guide surface F ₂₁ in the wire direction S (arrow) is in a range of 150 to 400 mm, preferably from 200 to 350 mm.

The FIG. 3 shows a longitudinal sectional view of the suction box 10 of the Schrägsiebformers 1 of the invention FIG. 2 , For the sake of clarity, the longitudinal section is also provided with a cut.

It can be clearly seen that the suction slots 12 of the suction box 10 are provided in the edge zone R _{L of} the screen 4, each with a displaceable intermediate strip 18, which are sealingly fitted between the two adjacent drainage strips 11.

In the edge region 10 _{L of} the suction box 10, the cover plate 22 is arranged, which supports the associated slide plate 20 flat. The plate covering 21 of the suction box 10 with a preferably curved guide surface F _{21 is also} attached to the respective cover plate 22, for example by means of a plurality of screw connections 23. The length L _{21 of} the guide surface F ₂₁ in the direction of wire run S (arrow) lies in a range of 150 to 400 mm, preferably from 200 to 350 mm.

The FIG. 4 shows a marginal and top sectional view of the suction box 10 of the Schrägsiebformers 1 of the invention FIG. 2 according to the section line XX.

The suction box 10 is provided in its edge region 10 _R with a contoured cover plate 22 which supports the associated slide plate 19 by support surface. Below the cover plate 22 of the slide plate 19 acting actuator 20 is arranged by means of a plurality of brackets 25. The cover plate 22 is provided with corresponding recesses 24 to allow the loading of the slide plate 19 by the spindle gear 20.21, 20.22.

The two intermediate strips 18 of a suction slot 12 together determine the suction zone width B _Z , which is smaller than the width B _{4 of} the sieve 4. The suction zone width B _{Z of} the suction box 10 is in the range of 1,000 to 11,000 mm, preferably in the range of 1,800 to 10,000 mm, in particular from 3,000 to 8,000.

For this purpose, the respective intermediate strip 18 has a displacement path V in the range from 1 to 500 mm, preferably from 25 to 200 mm, in particular from 50 to 150 mm, so that it and its two adjacent drainage strips 11 have a coverage Ü in the range from 100 to 400 mm, preferably from 125 to 300 mm, in particular from 50 to 150 mm. The two characteristics displacement path V and coverage Ü are merely indicated because they are sufficiently known to the skilled person.

In summary, it should be noted that the invention provides a Schrägsiebformer of the aforementioned type, which allows a change in the width of the fibrous web to be produced, in particular during its operation and in particular in the larger width ranges. This possibility of change is also subject to simple handling and is characterized by only minor additional costs in acquisition and operation.

Claims (11)

1. Inclined-wire former (1) of a machine for producing a fibrous web (2), in particular a long-fibred paper or wet nonwoven web, from at least one fibrous suspension (3), having a wire (4) which runs over a circumferential region (6) of a breast roll (5) and subsequently runs in the wire running direction (S), at least over some distance, inclined at an angle (α) with respect to the horizontal (H), in this inclined section (7) of the wire (4), at least one flowbox (8) applying the at least one fibrous suspension (3) to the top side of the wire (4), on the underside of the wire (4) there being arranged at least one dewatering element (9) for dewatering the at least one fibrous suspension (3) applied to the wire (4), and the dewatering element (9), formed as a suction box (10), being open towards the wire (4) in order to exert a suction action on the wire (4) and the at least one fibrous suspension (3) applied to the top side of the wire (4), and having a plurality of dewatering foils (11) which touch the wire (4), are spaced apart from one another, extend transversely with respect to the wire running direction (S) and delimit a plurality of suction slots (12),
   at least one suction slot (12) of the suction box (10) in the two edge zones (R_R, R_L) of the wire (4) each being provided with a displaceable intermediate foil (18), which in each case is fitted in a sealing manner between the two adjacent dewatering foils (11), the intermediate foils (18) of a suction slot (12) together determining a suction zone width (B_Z) which is smaller than the width (B₄) of the wire (4),
   it being possible for the intermediate foil (18) to be displaced by means of a sliding plate (19),
   characterized
   in that the sliding plate (19) is acted on by at least one actuating drive,
   in that, in the respective edge region (10_R, 10_L) of the suction box (10), there is arranged at least one covering plate (22), which mounts the sliding plate (19) flatly, and
   in that the covering plate (22) carries the actuating drive (20) on the underside.
2. Inclined-wire former (1) according to Claim 1,
   characterized in that
   a plurality, preferably all, of the suction slots (12) of the suction box (10) in the two edge zones (R_R, R_L) of the wire (4) are each provided with a displaceable intermediate foil (18).
3. Inclined-wire former (1) according to Claim 1 or 2,
   characterized in that
   the intermediate foils (18) arranged on one side of the suction box (10) can be displaced individually, in groups or together.
4. Inclined-wire former (1) according to one of the preceding claims,
   characterized in that
   the actuating drive (20) comprises a spindle drive (20.1), which acts on the sliding plate (19) via at least one spindle mechanism (20.21, 20.22).
5. Inclined-wire former (1) according to one of the preceding claims,
   characterized in that
   the intermediate foil (18) has a displacement travel (V) in the range from 1 to 500 mm, preferably from 25 to 200 mm, in particular from 50 to 150 mm.
6. Inclined-wire former (1) according to one of the preceding claims,
   characterized in that
   the intermediate foil (18) and its two adjacent dewatering foils (11) have an overlap (Ü) in the range from 100 to 400 mm, preferably from 125 to 300 mm.
7. Inclined-wire former (1) according to one of Claims 1 to 5,
   characterized in that
   the intermediate foil (18) and its two adjacent dewatering foils (11) have an overlap (Ü) in the range from 50 to 150 mm.
8. Inclined-wire former (1) according to one of the preceding claims,
   characterized in that
   the suction zone width (B_Z) of the suction box (10) lies in the range from 1000 to 11,000 mm, preferably in the range from 1800 to 10,000 mm, in particular from 3000 to 8000 mm.
9. Inclined-wire former (1) according to one of the preceding claims,
   characterized in that
   arranged immediately upstream of the suction box (10) in the wire running direction (S) is a plate covering (21) guiding the wire (4) and having a preferably curved guide surface (F₂₁).
10. Inclined-wire former (1) according to one of the preceding claims,
    characterized in that
    the flowbox (8) is constructed as a multilayer flowbox, a sectioned consistency control system preferably being provided for at least one layer of the multilayer flowbox.
11. Inclined-wire former (1) according to one of the preceding claims,
    characterized in that
    at least two flowboxes are provided, a sectioned consistency control system preferably being provided for at least one layer of a flowbox (8).

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