WO2013000843A1

WO2013000843A1 - Dewatering device for a machine for producing a fibrous web from at least one fibrous stock suspension

Info

Publication number: WO2013000843A1
Application number: PCT/EP2012/062178
Authority: WO
Inventors: Bernd Güldenberg; Joachim Grabscheid; Helmut Faix; Walter Schneider; Uwe Maier; Thomas Klein; Thomas RÜHL
Original assignee: Voith Patent Gmbh
Priority date: 2011-06-28
Filing date: 2012-06-25
Publication date: 2013-01-03
Also published as: DE102011078238A1

Abstract

The invention relates to a dewatering device (1) for a machine (100) for producing a fibrous web (2), in particular a paper, cardboard or packaging-paper web, from at least one fibrous stock suspension, having a main body (3) which is box-shaped and can preferably be loaded by a vacuum source (4), and having a plurality of dewatering foils (5) which are arranged on one side, preferably on the top side or on the underside, extend transversely with respect to the machine direction (L), are spaced apart and form a preferably flat dewatering surface (5.F). The dewatering device (1) according to the invention is characterized in that it is assigned at least one additional mass (M) which is coupled to the main body (3) in a sprung and/or swinging and/or floating manner.

Description

Dewatering device for a machine for producing a

Fiber web of at least one pulp suspension

The invention relates to a dewatering apparatus for a machine for producing a fibrous web, in particular a paper, board or packaging paper web, from at least one pulp suspension, with a box-shaped and preferably acted upon by a vacuum source body and with a plurality of one-sided, preferably upper or lower side ordered, extending transversely to the machine direction and spaced drainage strips, which form a preferably flat drainage surface.

Such a dewatering device is known for example from the document DE 10 2007 000 258 A1. The disclosed dewatering apparatus may be part of a twin-wire former of a machine for making a fibrous web from at least one pulp suspension, the twin-wire former having two circumferential and endless screens. The drainage strips of this dewatering device are fixedly arranged on a common support structure and the common support structure, in turn, is arranged interchangeably below the base body.

Components and assemblies of a machine for producing a fibrous web from at least one pulp suspension are stored in a variety of ways in a machine frame and thus mechanically coupled, whereby an interaction between them takes place. Thus, for example, a dewatering device is loaded with external forces by a sieve guided over it and by the water stripped off at dewatering strips of the dewatering device. This external excitation then causes a vibration of the dewatering device. It is known in the art that a complex interaction between machine speed, screen design and screen age, water level on the dewatering device, screen to drainage dewatering area, dewatering area geometry, dewatering device dewatering angle, dewatering strip width the dewatering device, open drainage surface of the dewatering device, and the like. Special stresses experienced the dewatering device in the starting process of the machine without pulp suspension, so only with water. Here, a lot of the headbox is discharged in the first dewatering elements, since no filter mat is present or built up by the fibers.

It is generally critical if, due to certain operating conditions, the oscillatory system becomes unstable and self-excited resonance vibrations occur. With an oscillation in the region of the natural frequency of the dewatering device, the oscillation amplitude increases beyond the admissible extent, which means that sufficient function of the dewatering device is no longer guaranteed and thus quality is impaired in the fibrous web to be produced. To ensure safe operation, it is therefore imperative to avoid these resonant vibrations.

The design of the dewatering device is therefore usually today so that the first natural frequency of the dewatering device is as high as possible within the scope of design options. The design of the cross section The basic body of the dewatering device is essential for the achievable rigidity and the resulting natural frequencies of the system.

The machine speeds and widths are already high today. If you want to avoid such resonances, the main body of the dewatering device must be very large dimensions. However, this is often hardly possible because the space is insufficient.

With increasing machine speeds and widths, this problem is increasingly exacerbated. Thus, the natural frequency of the main body of the dewatering device decreases with increasing width, unless the cross section is increased.

An increase in the permissible space could be realized only with considerable additional costs, since the dimensions of the machine would have to be increased. An increase in the rigidity of the body by selecting other materials with a higher modulus of elasticity, which would also increase the natural frequency result, is not economical due to the associated additional costs.

It always strives to increase machine speeds and widths, thereby improving the productivity of the machine. However, this finds its limit by the aforementioned vibration problems. From various documents vibration damping systems for machines for the production of fibrous webs are already known.

Thus, document EP 2 072 678 A1 discloses a method and a device for active suppression of vibrations and / or variations in a paper machine. The disclosed component of the paper machine is a headbox, in particular a headbox front wall or a headbox upper lip and the at least one pathogen is a felt, a drive and / or a Schiebschüttelung. The actuator acting on the component is an active vibration absorber (adaptronics), by means of which reactions are generated in the component which counteract the disturbances or variations underlying the disturbances caused by at least one exciter.

Furthermore, EP 2 161 372 A2 discloses a dryer section for a machine for producing and / or treating a fibrous web with a passive system for vibration damping. In this dryer section, the fibrous web is guided together with a drying wire around at least one drying cylinder and a suction deflecting roller adjacent thereto. The suction deflecting roller is associated with a contacting and non-rotating stabilizer to stabilize the web run in the area between the drying cylinder and the suction deflecting roller. For the purpose of passive vibration damping, the stabilizer is assigned at least one additional mass, which is resiliently coupled with it and / or pendulum and / or floating. It is therefore an object of the invention to influence the vibration behavior of a dewatering device of the type mentioned in that the sensitivity to externally excited vibrations is significantly reduced and that safe operation even under the influence of stimulating frequencies in the first natural frequency of the conventionally designed dewatering device is possible.

This object is achieved in a dewatering device of the type mentioned in the present invention that the dewatering device is associated with at least one additional mass that is resiliently and / or pendulum and / or floating coupled to the body. The object of the invention is completely solved in this way.

Due to the provision of at least one additional mass and by a possible vote of the basic body including drainage strips and the additional mass comprehensive multi-mass vibration system, the sensitivity to externally excited vibrations are significantly reduced, without requiring a modification of the remaining wire section would be required. In addition, safe operation is possible even under the influence of stimulating frequencies in the range of the first natural frequency of the conventionally designed dewatering device. By appropriate tuning of the multi-mass vibration system, safe operation is also possible under the influence of stimulating frequencies in the range of the first natural frequency of a system otherwise designed in a conventional manner. After the dewatering device with associated additional mass can be easily integrated into the existing installation spaces, high efficiency is guaranteed. In particular, any existing natural frequency of the main body, including the drainage strips, can be specifically influenced, thereby eliminating the previously existing limitations with regard to the machine width at machine speed, without requiring additional space in the resonance area. Moreover, the resulting overall system with the same susceptibility to vibration in the same speed range and the same machine width compared to conventionally designed systems in cross-section can be made significantly smaller, which saves a lot of space.

The additional mass is preferably coupled via a spring system or a spring damper system with the base body. Advantageously, the additional mass is coupled exclusively via said system with the main body. Thus, the suspension can at least partially form the system itself or be provided in addition to such a spring-damper system. Under a spring-damper system is a system to understand that causes both a resilient and a damping effect when swinging the additional mass. The components of the basic body together with drainage strips and the multi-mass oscillation system comprising in particular a spring system or a spring damper system with this additional mass are preferably tuned so that the vibration susceptibility of this multi-mass oscillation system is reduced to a minimum.

The center of gravity of the additional mass or the common center of gravity of the additional masses is preferably in or near the center of gravity of the main body, including drainage strips. It is advantageous here if the additional mass or the additional masses are on the whole of the order of magnitude of from 2 to 30%, preferably from 3 to 30%, in particular from 6 to 10%, of the total mass of the main body together with the drainage strips.

The additional mass is preferably suspended from the main body via the spring system or the spring damper system and / or via an additional suspension, wherein the additional mass is preferably coupled exclusively to the main body via a resilient suspension. Thus, the suspension can at least partially form itself the spring system or the spring-damper system and be provided in addition to a spring system or a spring-damper system. In the latter two cases, the suspension need not be resilient or springy and dampening itself. Basically, however, here is a resilient or a resilient and damping embodiment of the suspension conceivable, which may for example only have a damping effect. Furthermore, the additional mass is preferably designed in the form of a sphere, a rod, a cuboid, a cylinder and / or a polygon, since these Body shapes can be produced inexpensively. Preferably, the additional mass of metal or other material, in particular plastic.

The additional mass preferably extends over the entire width or over part of the width of the base body. In certain cases, however, it may also extend only over part of the width of the main body. It may also be advantageous if the additional mass extends at least substantially parallel to the main body. Furthermore, the additional mass is preferably arranged inside or outside the main body. If several additional masses are provided, then for example all additional masses within or all additional masses can be arranged outside the main body. It is also conceivable, however, to arrange part of the additional masses within and part of the additional masses outside the main body.

Also, bearing units are arranged on both sides of the base body, which preferably each comprise at least one self-damping spring unit or a separate spring and an additional damping unit. The additional damping unit in turn may comprise a gas or oil pressure damper.

Furthermore, the base body preferably comprises a closed body, which acts as a torsion profile transversely to the machine direction. In this case, the overall system can in particular be tuned such that preferably the first bending moment frequency in the direction of the first main axis of inertia and the first bending frequency in the direction of the second axis of inertia are influenced.

Since the above-mentioned vibration problems increase with increasing machine and web running speed and thus wire speed, the multi-mass vibration system according to the invention is preferably used in machine tools. or web travel speeds> 1 .200 m / min, preferably> 1 .400 m / min, in particular> 1, 500 m / min used.

The dewatering device according to the invention can also be used in a machine for producing a fibrous web, in particular paper, board or packaging paper web, from at least one pulp suspension. This results in the already mentioned advantages.

The dewatering device according to the invention may be the first dewatering device after a sieve table element, ie the second on a pre-dewatering section after a headbox.

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

Figure 1 is a schematic longitudinal sectional view of a first preferred embodiment of a dewatering device according to the invention for a machine for producing a fibrous web of at least one pulp suspension;

Figure 2 is a schematic longitudinal sectional view of a second preferred embodiment of a dewatering device according to the invention;

FIGS. 3 to 7 are various schematic illustrations of further preferred embodiments of a device according to the invention

Dehydrator;

Figure 8 is a schematic view of a preferred embodiment of an end-side storage unit of a main body of a dewatering device according to the invention; and

Figures 9 and 10 are two schematic representations of a wire section of a

Machine for producing a fibrous web from at least a pulp suspension each having a preferred embodiment of an inventive

Dehydrator. 1 shows a schematic longitudinal sectional view of a dewatering device 1 for a machine 100 not shown in detail for producing a fibrous web 2 (dashed line) of at least one pulp suspension. The dewatering device 1 is part of a wire section of the machine 100 not shown in detail for producing the fibrous web 2. The fibrous web 2 may in particular be a paper, cardboard or packaging paper web.

The dewatering apparatus 1 comprises a box-shaped main body 3, which can optionally be acted upon by a merely indicated and preferably controllable / regulable vacuum source 4. On one side, preferably on the upper or lower side, of the main body 3 are arranged a plurality of drainage strips 5 extending transversely to the machine direction L (arrow) and spaced apart, which form a preferably flat drainage surface 5.F having several drainage slots 6. The individual drainage strip 5 usually consists of a support body 7 and a wear body 8 facing away from the base body 3. Alternatively or additionally, the drainage area may also be perforated in a manner not shown.

The dewatering device 1 is now according to the invention associated with an additional mass M, which is resiliently and / or oscillating and / or floating coupled to the base body 3. The additional mass M may extend over the entire width B (arrow) or over part of the width B (arrow) of the main body 3. The arranged within the body 3 additional mass M is in the illustrated embodiment via two spring-damper systems 9, each comprising at least one spring 10 and at least one damper 1 1, coupled to the base body 3. Of course, the coupling can also be implemented via a spring system. The components of the base body 3 together with drainage strips 5 and the multi-mass vibration system comprising a spring damper system 9 coupled thereto with at least one additional mass M are tuned so that the vibration susceptibility of this multi-mass vibration system is reduced to a minimum in the critical frequency range.

Furthermore, the additional mass M is in the order of 2 to 30%, preferably from 3 to 30%, in particular from 6 to 10%, of the total mass of the base body 3 together with drainage strips 5.

The additional mass M is executed in the illustrated embodiment in the form of a sphere. However, it can also be embodied in the form of a rod, a cuboid, a cylinder and / or a polygon. Ideally, the additional mass M consists of metal or another material, in particular plastic.

Furthermore, the base body 3 comprises a closed and dashed body 12, which acts as a Torsionsprofil transverse to the machine direction L (arrow). The machine or web running speed is also> 1 .200 m / min, preferably> 1 .400 m / min, in particular> 1,500 m / min.

FIG. 2 shows a schematic longitudinal section of a second dewatering device 1. Since the basic structure of the illustrated dewatering apparatus 1 corresponds to the basic structure of the dewatering apparatus 1 shown in FIG. 1, reference is made to the description of the figures. The dewatering device 1 is now according to the invention again associated with an additional mass M, which is resiliently and / or oscillating and / or floating coupled to the base body 3. The additional mass M can extend over the entire width B (arrow) or over part of the width B (arrow) of the main body 3.

The arranged outside of the base body 3 additional mass M is in the illustrated embodiment via a spring-damper system 9, comprising a spring 10 and a damper 1 1, coupled to the base body 3. The additional mass M is coupled exclusively to the main body 3 via the spring damper system 9. Of course, the coupling can also be implemented via a spring system. Extending to the dewatering device 1 shown in FIG. 1, the center of gravity M.sub.S of the additional mass M lies in or near the center of gravity 3.S.sub.S of the main body 3 together with the drainage strips 5.

FIGS. 3 to 7 show various schematic representations of further drainage devices 1, the respective basic structure of which corresponds to the individual basic structure of the drainage devices 1 illustrated in FIGS. 1 and 2. Thus, reference is made to their description of figures. The respectively possibly arranged on or in the base body 3, which is a torsion profile transverse to the machine direction, is shown explicitly.

The dewatering device 1 of Figure 3 is now in turn associated with an additional mass M, which is resiliently and / or oscillating and / or floating coupled to the base body 3. The additional mass M arranged outside the main body 3 is coupled to the main body 3 via a spring damper system 9, comprising a spring 10 and a damper 11, and can extend over the entire width B (double arrow) or over part of the width B (FIG. Double arrow) of the main body 3 erstre-.

By contrast, the dewatering apparatus 1 of FIG. 4 is now assigned two additional masses M, which are resiliently coupled to the main body 3 and / or swinging and / or floating.

The respective additional mass M arranged outside the main body 3 is coupled to the main body 3 via a spring-damper system 9, comprising a spring 10 and a damper 11. The two additional masses M preferably have the same properties as weight and the like and they are ideally arranged symmetrically to the center of the main body 3.

And the dewatering device 1 of Figure 5 is now in turn associated with an additional mass M, which is resiliently and / or oscillating and / or floating coupled to the base body 3.

The arranged outside of the base body 3 additional mass M is coupled via two spring-damper systems 9, each comprising at least one spring 10 and at least one damper 1 1, with the base body 3. Of course, the coupling can also be implemented via a spring system.

The additional mass M arranged outside the main body 3 can extend over the entire width B (double arrow) or over part of the width B (double arrow) of the main body 3. FIG. 6 shows a modification of the dehydrating device 1 shown in FIG. Thus, the additional mass M and the spring-damper system 9 suspended by an additional suspension 13 on the base body 3, wherein the additional mass M is preferably coupled exclusively to the main body 3 via the resilient and damping suspension 13. Finally, FIG. 7 shows a modification of the dehydrating device 1 shown in FIG.

The dewatering device 1 of Figure 7 is now in turn associated with an additional mass M, which is resiliently and / or oscillating and / or floating coupled to the base body 3.

The arranged within the body 3 additional mass M is coupled via a spring-damper system 9, comprising a spring 10 and a damper 1 1, with the base body 3 and can over the entire width B (double arrow) or over a portion of the width B (double arrow) of the main body 3 extend.

FIG. 8 shows a schematic view of an end-side bearing unit 14 of a main body 3 of a dewatering device 1.

The individual storage unit 14, which is arranged on the main body 3, each comprises at least one additional damping unit 15 which is provided between a bearing profile 16 and the stiffening 17 of the machine 100 (not shown) for producing a fibrous web 2 (dashed line) of at least one pulp suspension is.

FIGS. 9 and 10 show two schematic representations of a wire section 200 of a machine 100, which is only partially shown, for producing a fibrous web 2 from at least one pulp suspension. 9 shows a Einsiebpartie in an embodiment of a wire former, as disclosed for example in the publication DE 100 09 190 A1. The relevant content of this document is hereby made the subject of the present description.

And FIG. 10 shows a two-wire section in the form of a gap former, as disclosed, for example, in the publication DE 43 28 024 A1. The relevant content of this document is hereby made the subject of the present description.

The dewatering device 1 according to the invention shown schematically and at least partially in FIGS. 1 to 8 is particularly suitable for use in a machine 100 shown at least in sections in FIGS. 9 and 10 for producing a fibrous web 2 from at least one pulp suspension.

In this case, the dewatering device 1 according to the invention may be the first dewatering device after a sieve table element, that is, the second on a pre-dewatering section after a headbox (see Figure 9).

In summary, it should be noted that the vibration behavior of a dewatering device of the type mentioned above is influenced by the invention that the sensitivity to externally excited vibrations is significantly reduced and that safe operation is possible even under the influence of stimulating frequencies in the first natural frequency of the conventionally designed dewatering device. LIST OF REFERENCE NUMBERS

1 drainage device

2 fibrous web

3 basic body

3.S Center of gravity of the body including drainage strips

4 vacuum source

5 drainage bar

5.F drainage area

6 drainage slot

7 supporting body

8 wear body

9 spring damper system

10 spring

1 1 damper

12 bodies

13 suspension

14 storage unit

15 damping unit

16 bearing profile

17 strangulation

100 machine for producing the fibrous web

200 wire section

B width (arrow; double arrow)

L machine direction (arrow)

M additional mass

M.S focus of the additional mass

Claims

Dewatering device for a machine for producing a fibrous web from at least one pulp suspension. Claims

1 . Dewatering device (1) for a machine (100) for producing a fibrous web (2), in particular a paper, board or packaging paper web, from at least one pulp suspension, with a box-shaped and preferably by a vacuum source (4) acted upon basic body (3) and with a plurality of drainage strips (5), which are arranged on one side, preferably on the top or bottom, and extend transversely to the machine direction (L) and form a preferably flat drainage surface (5.F),

characterized,

in that the dewatering device (1) is assigned at least one additional mass (M) which is resiliently and / or oscillatingly and / or floatingly coupled to the main body (3).

2. Dewatering device (1) according to claim 1,

characterized,

the additional mass (M) is coupled to the main body (3) via a spring system or a spring damper system (9).

3. drainage device (1) according to claim 2,

characterized,

the additional mass (M) is coupled exclusively to the main body (3) via the spring system or the spring damper system (9).

Dewatering device (1) according to one of the preceding claims, characterized

in that the components of the multi-mass vibration system comprising the main body (3) together with the drainage strips (5) and the at least one additional mass (M), in particular coupled via a spring system or a spring damper system (9), are adjusted such that the vibration susceptibility of this excess mass Vibration system in the critical frequency range is reduced to a minimum.

Dewatering device (1) according to one of the preceding claims, characterized

that the center of gravity (M.S) of the additional mass (M) or the common center of gravity of the additional masses is in or near the center of gravity (3.S) of the main body (3) together with drainage strips (5).

Dewatering device (1) according to one of the preceding claims, characterized

that the additional mass (M) or the additional masses total in the order of 2 to 30%, preferably from 3 to 30%, in particular from 6 to 10%, of the total mass of the base body (3) including drainage strips (5).

Dewatering device (1) according to one of the preceding claims, characterized

that the additional mass (M) via the spring system or the spring-damper system (9) and / or an additional suspension (13) on the base body (3) is suspended, wherein the additional mass (M) preferably exclusively via a resilient or a resilient and damping suspension (13) is coupled to the main body (3).

8. Dewatering device (1) according to one of the preceding claims, characterized in that

the additional mass (M) is designed in the form of a sphere, a rod, a cuboid, a cylinder and / or a polygon.

9. Drainage device (1) according to one of the preceding claims, characterized in that

that the additional mass (M) extends over the entire width (B) or over part of the width (B) of the main body (3).

10. Dewatering device (1) according to one of the preceding claims, characterized in that

that the additional mass (M) is arranged inside or outside of the main body (3).

1 1. Dewatering device (1) according to one of the preceding claims, characterized

in that bearing units (14) are arranged on both sides of the base body (3), each comprising at least one self-damping spring unit or a separate spring and an additional damping unit (15).

12. Dewatering device (1) according to one of the preceding claims, characterized in that

in that the base body (3) comprises a closed body (12) which acts as a torsion profile transversely to the machine direction (L).

13. Dewatering device (1) according to one of the preceding claims, characterized in that

the machine or web running speed is> 1 .200 m / min, preferably> 1 .400 m / min, in particular> 1, 500 m / min.

14. Machine (100) for producing a fibrous web (2), in particular paper, cardboard or packaging paper web, from at least one pulp suspension with at least one dewatering device (1) according to one of the preceding claims.