DE102010030352A1 - Headbox for a machine for producing a fibrous web - Google Patents

Abstract

The invention relates to a headbox (1) for a machine for producing a fibrous web (3), in particular a paper, cardboard or packaging paper web, from at least one fibrous suspension (2), with a transverse distribution pipe feeding the at least one fibrous suspension (2) and a transverse distribution pipe (4.1) comprehensive feed device (4), with a downstream and a plurality of flow channels (6) arranged in rows (Z; Z1 to Z5) and in columns (S) having perforated distribution pipe plate (5), with a downstream therefrom intermediate channel (7) extending over the width (B) of the headbox (1), with a downstream turbulence generating means (8) with a plurality of flow channels (9) arranged in rows (Z) and in columns (S; S1 to S4) , and with a headbox nozzle (11) directly adjoining the turbulence generating means (8) and having a nozzle gap (12). The headbox (1) according to the invention ilust (ps) is provided, which essentially consists of a first pressure loss (p1) between the feed device (4, 4.1) and the intermediate channel (7) and a second pressure loss (p2) in the turbulence generating means (8 ), wherein the first pressure loss (p1) assumes a value in the range from 15 to 85%, preferably from 25 to 85%, in particular from 40 to 85%, that that between the perforated distributor plate (5) and the turbulence generating means (8) arranged intermediate channel (7) has a free intermediate channel length (7.L) of ≥ 50 mm, preferably ≥ 120 mm, in particular ≥ 200 mm, and that the cross-sectional ratio (Q) between inlet (4.Z) and intermediate channel (7) a value in the range from 0.1 to 2, preferably from 0.15 to 1.5, in particular from 0.2 to 1, assumes.

Description

The invention relates to a headbox for a machine for producing a fibrous web, in particular a paper, board or packaging paper web, from at least one pulp suspension, comprising a supplying the at least one pulp suspension and a transverse distributor tube feeding device, with a downstream and a plurality of in an in-line, across the width of the headbox extending intermediate channel, with a downstream turbulence generating means having a plurality of arranged in rows and in columns flow channels, and with the turbulence generating means immediately adjacent and a nozzle gap having headbox.

Such a headbox is for example from the document DE 198 43 729 A1 known.

In this headbox having a machine-width intermediate headbox, the pulp suspension coming from a constant part known to the person skilled in the art is passed through the transverse distributor tube, then deflected before or in the distributor tube perforated plate in the machine direction (MD), separated and fed to the machine-width intermediate channel. In the subsequent turbulence generating means, the flow, ie at least the pulp suspension is uniformed, any added dilution water, in particular white water, is mixed in and the entire suspension is fluidized. For the "crossflow-free" filling of the downstream headbox nozzle, a very good throughput constancy must be achieved by the turbulence generating means in the cross machine direction (CD). In the headbox, the suspension is finally accelerated to machine speed.

A disadvantage of such a headbox is that its transverse distribution tube is provided with a return system for excess pulp suspension (cf. 4a ). This feedback system usually has a return line and a flow control, comprising a control unit including at least one sensor (pressure sensor), at least one actuator (spool) and various lines on. Such a return system causes incalculable costs in both purchase, operation and maintenance, and it is also sluggish in function and prone to repairs.

Furthermore, from the document DE 102 08 610 A1 already known a headbox whose pressure loss in the turbulence generating means is greater than 0.3 bar, preferably greater than 0.2 bar, and the transverse distribution tube has a tapered in the flow direction of the pulp suspension cross-section and connected only in the region of its largest cross-section to a supply line for the pulp suspension is. The pulp suspension fed to the transverse distribution tube is discharged exclusively via the headbox nozzle.

Although the disadvantageous recycling system for excess pulp suspension can be avoided with such a headbox, the technical implementation of such a headbox is more than difficult. In particular, this in turn can have a high energy consumption and an unstable fiber orientation (transverse) profile.

It is therefore an object of the invention to improve a headbox of the type mentioned in such a way that the aforementioned disadvantages of the prior art as far as possible, preferably completely eliminated. In this case, the pressure loss for preferably uniform distribution of the pulp suspension should be as low as possible and optimally distributed. Also, the energy consumption of the headbox should be significantly reduced, the stability of the fiber orientation (transverse) profile improved and the consumption of chemicals, especially retention agents are reduced.

This object is achieved in a headbox of the type mentioned in the present invention that a system pressure loss is provided, which is composed essentially of a first pressure loss between the feeder and the intermediate channel and a second pressure loss in the turbulence generating means, wherein the first pressure loss is a value in Range of 15 to 85%, preferably from 25 to 85%, in particular from 40 to 85%, assumes that disposed between the distribution well plate and the turbulence generating means intermediate channel a free intermediate channel length of ≥ 50 mm, preferably of ≥ 120 mm, in particular of ≥ 200 mm, and that the cross-sectional ratio between inlet and intermediate channel is a value in the range of 0.1 to 2, preferably from 0.15 to 1.5, in particular from 0.2 to 1, assumes.

The object of the invention is completely solved in this way.

The inventive design of the headbox of the type mentioned provides a most extensive, preferably complete avoidance of the aforementioned disadvantages of the prior art and a much improved Fulfillment of the particular technological requirements.

The headbox according to the invention achieves a flow in the cross-machine direction as constant as possible inflow of pulp suspension in the headbox. This is made possible above all by the fact that its operation takes place without recirculation, there is a special pressure loss distribution between its headbox areas and there is a minimum distance, ie a minimum length of the intermediate channel, between the two grids, ie the distribution well plate and the turbulence generating means.

And the aspect ratio between inlet and intermediate channel favors a very good transverse distribution of at least one pulp suspension in the width direction of the head box according to the invention. The cross-section of the inlet is by definition the largest cross-sectional area of the feeder, that is, the initial cross-sectional area of the feeder, especially the transverse divider tube, whereas the cross-section of the intermediate channel is by definition the free cross-sectional area of the machine-width intermediate chamber, ie the downstream total area of the distribution well plate.

Also, in the headbox of the head box according to the invention at least one, well-known to those skilled separator, in particular a blade be arranged. If a plurality of separating elements, in particular lamellae, are arranged in the headbox of the headbox according to the invention, then they can have different lengths and possibly also different properties, such as surface contours and the like.

The second pressure loss in the turbulence-generating means of the head box according to the invention preferably assumes a value in the range from 0.1 to 1.5 bar, preferably from 0.2 to 1.0 bar, in particular from 0.3 to 0.5. This region for the second pressure loss is particularly advantageous with regard to a good and procedurally necessary fluidization of the pulp suspension.

And the Verteilrohrlochplatte the head box according to the invention is preferably provided with hydraulic elements for pressure recovery, such as diffusers, stage diffusers or short diffusers. This flow guidance allows a trouble-free and clog-free inflow from the transverse distribution tube into the distribution well plate at a speed of 4-16 m / s. The necessary flow energy must be converted back into pressure energy through the diffusers in the distribution well plate.

Furthermore, the at least one pulp suspension fed to the feed device of the head box according to the invention is preferably fed exclusively to the downstream flow channels of the distribution tube hole plate. Thus, a headbox without a recirculation of the pulp suspension can be realized and the amount of pulp suspension at the edge varies to a significant extent less. Moreover, the cross section of the transverse distribution tube tapering in the flow direction of the pulp suspension and the connection of the supply line for the pulp suspension in the area of the largest cross section of the distributor ensure that the pulp suspension is fed to the distribution well plate under approximately equal pressures.

In a further preferred practical embodiment, a plurality of means spaced apart from one another in the width direction of the headbox is provided for preferably controllable metering of a fluid in partial fluid streams into the at least one pulp suspension, the individual means each having a plurality of metering channel opening and opening centerline, includes Zudosierkanälen opening at different heights and connected to a common supply channel.

This embodiment allows the realization of a technically simple and reliable Zudosiersystems, which is also still inexpensive and technically relatively easy to perform. Thus, in particular, the stated arrangement of Zudosierkanäle over the height and the dimensioning of the respective Zudosierkanals affect extremely positive to the required good to very good mixing quality of pulp suspension and fluid, the desired low effective width and the necessary low mapping offset.

And the impact point of the opening center line of the individual Zudosierkanalöffnung on the turbulence generating means is preferably approximately centrally, preferably centrally between the two column planes of two adjacent flow channels. With this embodiment, the throughput constancy of fluid in the width direction of the headbox according to the invention in the turbulence generating means can be made independent of the amount of pulp suspension which can be differently metered in the width direction of the headbox.

Further, the Zudosierkanalöffnung the means for preferably controllable dosing of the fluid in fluid streams at least one pulp suspension to the turbulence generating means of the headbox according to the invention preferably a vertical distance in the range of 2 to 50 mm, preferably from 3 to 40 mm, in particular from 5 to 20 mm, on. This distance ranges ensure the necessary mixing quality of the fluid with the pulp suspension, even with different operating parameters, so that the best conditions for the production of a fibrous web with good to very good quality characteristics are given.

The respective means for preferably regulatable / controllable metering of the fluid in partial fluid streams into the at least one fibrous suspension preferably comprises an injector, as also described in the German patent application DE 10 2008 054 898.7 of 18.12.2008 (Applicant's File: HPA14265 DE - "MJ II-DoS-TE Geometry"). The relevant disclosure content is hereby made the subject of the present description.

Moreover, the fluid preferably consists of water, in particular white water or clear water, or of at least one pulp suspension whose concentration differs from the average concentration of the at least one fibrous suspension flowing in the headbox. These types of fluids have already proven themselves in similar applications.

The transverse distribution tube of the headbox according to the invention preferably has at least one removable component in the region of its preferably smallest end-side cross-section, the removable component preferably having a rectangular cross-section. This removable component greatly improves the ease of maintenance and cleaning of the headbox. Due to the preferably rectangular cross section, the hydraulic height of the component is maintained. As a result, the reduction of the cross section is only uniaxial.

Also, the component is preferably designed as a flap part and connected by means of at least one hinge connection and associated attachment to the transverse distribution tube. The articulation is upstream, downstream or side mounted. Such a hinge connection belongs to the well-known state of the art and has already proven itself in many diverse applications. However, the component may of course also be connected to the distributor by means of a plurality of screw connections or by means of a plurality of slide connections.

The component is designed according to a further aspect of the invention as a cleaning access for the distributor and / or as a sampling point for pulp suspension. These embodiments are characterized in particular by a practical benefit; So they are beneficial in many ways

Of course, the headbox according to the invention can also be designed as a multi-layer headbox with at least one separating element. As a result, a multilayer fibrous web having different layer qualities, in particular higher-quality outer layers, can be produced.

The at least one separating element of the multi-layer headbox can have a minimum rigidity both in the longitudinal direction and in the transverse direction, which assumes at least a value of ≥ 40 N / mm in certain regions. As a result, a flutter and / or a curvature of the at least one arranged in the headbox nozzle separating element is effectively avoided, at least during operation of the multi-layer casserole and favors the production of a fibrous web with improved properties.

The headbox according to the invention is outstandingly suitable for use in a machine for producing a fibrous web, in particular paper, cardboard or packaging paper web. The fibrous web produced in the machine with at least one headbox according to the invention has consistently excellent properties, since, among other things, the control of both its fiber orientation transverse profile and its basis weight cross-section is possible.

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

1 a vertical and schematic longitudinal sectional view of a first preferred embodiment of a headbox according to the invention for a machine for producing a fibrous web of at least one pulp suspension;

2 a vertical longitudinal sectional view of a preferred embodiment of a distribution well plate of a head box according to the invention;

3 a vertical and schematic longitudinal sectional view of a second preferred embodiment of a headbox according to the invention for a machine for producing a fibrous web of at least one pulp suspension;

4 a schematic side view of the means for preferably adjustable / controllable metered addition of a fluid in the 3 illustrated head box according to the invention;

5 a horizontal, partial and schematic longitudinal section of the in the 3 illustrated head box according to the invention;

6 a schematic front view of a preferred embodiment of a transverse distribution pipe of a head box according to the invention;

7 a schematic side view of a preferred embodiment of a transverse distribution of a headbox according to the invention; and

8th an exemplary pressure curve in a feeder, in particular in a transverse distribution pipe of a head box according to the invention for a machine for producing a fibrous web of at least one pulp suspension.

The 1 shows a vertical and schematic longitudinal sectional view of a first preferred embodiment of a head box according to the invention 1 for a machine for producing a fibrous web 3 from a pulp suspension 2 (Arrow). The illustrated headbox invention 1 can of course also be designed as a multi-layer casserole, the at least two different pulp suspensions for the production of the fibrous web 3 used. The fibrous web 3 may be in particular a paper, cardboard or packaging paper web.

The headbox according to the invention 1 has a one pulp suspension 2 (Arrow) feeding feeder 4 in a refinement of a transverse distribution tube known to the person skilled in the art 4.1 on.

The feeder 4 closes downstream of a distribution well plate 5 on, a plurality of arranged in rows Z and in columns S flow channels 6 having.

Again downstream of the distribution well plate 5 closes on the width B (arrow) of the head box according to the invention 1 extending intermediate channel 7 at.

The intermediate channel 7 Downstream is a turbulence generating means 8th with a plurality of flow channels arranged in rows Z and in columns S. 9 , During operation of the head box according to the invention 1 becomes the pulp suspension 2 (Arrow) in the turbulence generating means 8th divided into pulp suspension sub-streams and after exiting the turbulence generating means 8th in a machine-wide chamber 10 in an embodiment of a nozzle gap 12 having headbox nozzle 11 reunited to form a machine-wide fibrous web 3 to enable. The flow channels 9 are formed in a known manner preferably as thin-walled turbulence tubes and / or turbulence tube inserts with at least partially constant, at least partially diverging, at least partially converging and / or discontinuous cross-sectional areas. Also, in the headbox 11 at least one, the expert well-known and not explicitly shown separating element, in particular a blade be arranged. Should several separating elements, in particular slats in the headbox nozzle 11 may be arranged, they may have different lengths and possibly also different properties, such as surface contours and the like.

The headbox 11 can on the outlet side at least one side with a dashed line indicated aperture 13 be provided.

In the headbox according to the invention 1 is now a system pressure loss p _{s is} provided, which essentially consists of a first pressure loss p ₁ between the feeder 4 and the intermediate channel 7 and a second pressure loss p ₂ in the turbulence generating means 8th composed. The first pressure loss p ₁ assumes a value in the range of 15 to 85%, preferably 25 to 85%, in particular 40 to 85%, whereas the second pressure loss p ₂ in the turbulence generating means 8th a value in the range of 0.1 to 1.5 bar, preferably from 0.2 to 1.0 bar, in particular from 0.3 to 0.5 bar, assumes (see also 3 ).

Furthermore, it has between the Verteilrohrlochplatte 5 and the turbulence generating means 8th arranged intermediate channel 7 a free intermediate channel length 7.L of ≥ 50 mm, preferably ≥ 120 mm, in particular ≥ 200 mm. In the area of the free intermediate channel length 7.L is the intermediate channel 7 machine-wide trained (see also 3 ).

The cross-sectional ratio Q between inlet 4.Z and intermediate channel 7 Moreover, it assumes a value in the range from 0.1 to 2, preferably from 0.15 to 1.5, in particular from 0.2 to 1 (cf. 3 ).

And the aspect ratio Q between inlet 4.Z and intermediate channel 7 favors a very good transverse distribution of at least one pulp suspension 2 in the width direction Y (arrow) of the head box according to the invention 1 , The cross section Q4 of the inlet 4.Z is the largest by definition Cross sectional area 4.Qmax the feeder 4 , ie the initial cross-sectional area 4.Qmax the feeder 4 , in particular the transverse distribution tube 4.1 whereas the cross section 7.Q of the intermediate channel 7 by definition, the free cross-sectional area 7.Qfrei the machine-width intermediate chamber 7 that is, the downstream total area 5.F the distribution pipe hole plate 5 is.

The feeding device 4 fed pulp suspension 2 (Arrow) is exclusively the downstream downstream flow channels 6 the distribution pipe hole plate 5 fed.

The 2 shows a vertical longitudinal sectional view of a preferred embodiment of a distribution well plate 5 a headbox according to the invention 1 for a machine for producing a fibrous web from a pulp suspension with different channel cross sections 6.Q , Such a distribution well plate 5 For example, in the in the 1 Headbox according to the invention shown 1 be used.

The distribution hole plate 5 has, for example, five lines Z1 to Z5 on flow channels 6 and several columns S on flow channels 6 on. All flow channels 6 have a consistently round channel cross-section 6.Q but in different forms and configurations. Also, all flow channels 6 on the inlet side with a respective intake chamfer known to the person skilled in the art 14 Mistake.

The flow channels 6 The two upper rows Z4, Z5 initially have a constant channel cross-section 6.Q on, which is ultimately a steady expansion 15 , in particular a cone 15.1 with a cone angle α of ≤ 30 °.

The flow channel 6 the middle row Z3 initially again has a constant channel cross-section 6.Q up, which in the end two jump-like extensions 16 , in particular increments 16.1 . 16.2 experiences.

The flow channels 6 The two lower rows Z1, Z2 initially again have a constant channel cross-section 6.Q up, which ultimately only a jump-like expansion 17 , in particular a step change 17.1 experiences.

Every single flow channel 6 the distribution pipe hole plate 5 Thus, at least initially has a round channel cross-section 6.Q with a channel diameter 6.D. and finally forms at least one diffuser 18 due to at least one extension 15 . 16 . 17 out. The mean channel diameter 6.DM of the single flow channel 6 the distribution pipe hole plate 5 and the length 5.L the distribution pipe hole plate 5 are in a ratio of 1: 2 to 1:10, preferably from 1: 3 to 1: 8, in particular from 1: 4 to 1: 5.

The distribution hole plate 5 is thus in the manner explained with hydraulic elements for pressure recovery, such as diffusers 18 , Stage diffusers or short diffusers, provided.

The 3 now shows a vertical and schematic longitudinal sectional view of a second preferred embodiment of a head box according to the invention 1 for a machine for producing a fibrous web 3 from a pulp suspension 2 (Arrow). The illustrated headbox invention 1 can of course also be designed as a multi-layer casserole, the at least two different pulp suspensions for the production of the fibrous web 3 used. The fibrous web 3 may be in particular a paper, cardboard or packaging paper web.

Since the illustrated headbox invention 1 in essential areas in the 1 Headbox according to the invention shown 1 will be referred to its description and presentation.

In extension to that in the 1 Headbox according to the invention shown 1 are in the illustrated headbox according to the invention 1 now in the intermediate channel 7 several in the width direction Y (arrow) of the head box according to the invention 1 spaced apart means 19 for the preferably controllable metered addition of a fluid 20 (Arrow) in partial fluid streams 20.T (Arrows) in the pulp suspension 2 (Arrow) provided. This includes the individual agent 19 in each case a plurality of a respective Zudosierkanalöffnung 21.O and aperture centerline 21.M exhibiting, opening at different heights and with a common supply channel 22 connected metering channels 21 (see. 4 ).

The metering channel opening 21.O of the single agent 19 for preferably controllable metered addition points to the turbulence generating means 8th a vertical distance A in the range of 2 to 50 mm, preferably from 3 to 40 mm, in particular from 5 to 20 mm.

The means 19 for preferably controllable metered addition preferably have a pitch width TB of N x 25 mm or N x 33.3 mm, where N is preferably a natural number.

The respective means 19 for preferably controllable metered addition is as an injector 19.1 educated. And the fluid 20 (Peil) consists of water, in particular white water or clear water, or from at least one pulp suspension whose concentration is determined by the average concentration of at least one in the Headbox according to the invention differs streaming pulp suspension.

The 4 shows a schematic side view of the agent 19 for preferably controllable metered addition of a fluid 20 (Arrow) of the in the 3 Headbox according to the invention shown 1 for a machine for producing a fibrous web from a pulp suspension.

The metering channels opening at different heights 21 of the agent 19 for preferably controllable metered addition D are arranged at equal intervals and the common supply channel 22 of the agent 19 for preferably controllable metered addition has a circular cross-sectional area 22.Q with a diameter 22.D from 6 to 20 mm, preferably from 10 to 15 mm. The one with the common supply channel 22 connected metering channel 21 of the agent 19 For preferably controllable metered addition, moreover, has a circular cross-sectional area 21.Q with a diameter 21.D from 2 to 10 mm, preferably from 4 to 6 mm.

That as an injector 19.1 trained funds 19 for preferably controllable metered addition has a length 19.L in the range of 60 to 350 mm, preferably 100 to 250 mm, and in dependence on the height of the intermediate chamber of the head box according to the invention 1 a height 19.H in the range of 50 to 300 mm, preferably 75 to 250 mm. The means 19 for preferably controllable metered addition preferably have a pitch width TB of N x 25 mm or N x 33.3 mm, where N is preferably a natural number.

The injector 19.1 is also in the German patent application DE 10 2008 054 898.7 of Dec. 18, 2008 (Applicant's File: HPA14265 DE - "MJ II-DoS-TE Geometry"). The relevant disclosure content is hereby made the subject of the present description.

The 5 shows a horizontal, partial and schematic longitudinal section of the in the 3 Headbox according to the invention shown 1 for a machine for producing a fibrous web 3 from a pulp suspension 2 (Arrow).

The headbox according to the invention 1 has the pulp suspension 2 (Arrow) feeding feeder 4 in a refinement of a transverse distribution tube known to the person skilled in the art 4.1 on. The feeder 4 closes downstream of the distribution well plate 5 on, a plurality of arranged in rows Z and in columns S flow channels 6 having. Again downstream of the distribution well plate 5 closes over the width B (double arrow) of the head box invention 1 extending intermediate channel 7 at. The intermediate channel 7 Downstream downstream is the turbulence generating means 8th with a plurality of flow channels arranged in rows Z and in columns S. 9 , And the turbulence generating agent 8th closes immediately the die gap 12 having headbox nozzle 11 at.

In the intermediate channel 7 are several in the width direction Y (double arrow) of the head box according to the invention 1 spaced apart means 19 for preferably controllable metered addition of the fluid 20 (Arrow) in partial fluid streams 20.T (Arrows) in the pulp suspension 2 (Arrow) provided. This includes the individual agent 19 in each case a plurality of a respective Zudosierkanalöffnung 21.O and aperture centerline 21.M having metering channels 21 (see. 4 ).

The metering channel opening 21.O of the single agent 19 for preferably controllable metering points to the turbulence generating means 8th a vertical distance A in the range of 2 to 50 mm, preferably from 3 to 40 mm, in particular from 5 to 20 mm.

And the impact point C of the aperture centerline 21.M the individual Zudosierkanalöffnung 21 on the turbulence generating means 8th is approximately centrally, preferably centrally between the two column planes S1 to S4 of two adjacent flow channels 9 ,

The means 19 for preferably controllable metered addition preferably have a pitch width TB of N x 25 mm or N x 33.3 mm, where N is preferably a natural number.

Also is in the 5 it can be seen that the transverse distribution tube 4.1 one in the flow direction R (arrow) of the pulp suspension 2 tapered cross-section Q4 and that it in the region of its largest cross-section of a non-illustrated, the skilled person, however, known supply line for the pulp suspension 2 connected.

The 6 shows a schematic front view of a preferred embodiment of a transverse distribution tube 4.1 , So a feeder 4 a headbox according to the invention 1 ,

The transverse distribution pipe 4.1 has in the region of its preferably smallest end-side cross section Q4 at least one removable component 23 on, which preferably has a rectangular cross-section 23.QR has. The component 23 is as a folding part 23.1 formed, which by means of at least one hinge connection 24 (Dot-dash line) and associated attachment with the transverse distribution tube 4.1 connected is. The articulation 24 is in the execution according to the 6 mounted upstream; However, it can also be mounted downstream or laterally in a further embodiment. Alternatively or additionally, the component 23 , in construction not shown, also be connected by means of a plurality of screw or by means of a plurality of slide connections to the manifold.

The 7 shows a schematic side view of a preferred embodiment of a transverse distribution tube 4.1 a headbox according to the invention 1 ,

The transverse distribution pipe 4.1 has a flow direction R (arrow) of the pulp suspension 2 tapered cross-section Q4 up and it's in the area of its largest cross section Q4 to a merely indicated supply 25 (Arrow) for the pulp suspension 2 connected. Furthermore, the largest cross-sectional area 4.Qmax the feeder 4 , ie the initial cross-sectional area 4.Qmax the feeder 4 , in particular the transverse distribution tube 4.1 shown.

The cross distribution pipe 4.1 fed pulp suspension 2 (Arrow) is exclusively the downstream downstream flow channels 6 the distribution pipe hole plate 5 fed.

Further, the transverse distribution pipe 4.1 with a closed and opened component 23 or folding part 23.1 , which by means of the hinge connection 24 and associated attachment with the transverse distribution tube 4.1 is connected shown. The component 23 or folding part 23.1 is preferably designed as a cleaning access and / or as a sampling point.

The 8th shows an exemplary pressure loss curve in a feed device, in particular in a transverse distribution of a headbox according to the invention for a machine for producing a fibrous web of at least one pulp suspension due to an effective pipe friction. On the abscissa the distance from the recirculation side in [mm], on the left ordinate the velocity in the lateral distribution pipe in [m / s] and on the right ordinate the pressure loss dp in [mbar] is plotted.

• 1. DE 10 2008 054 893.6 vom 18.12.2008: HPA14251 DE – „MJ II-3-Spalten”;
• 2. DE 10 2008 054 894.4 vom 18.12.2008: HPA14252 DE – „MJ II-EdgeModule”;
• 3. DE 10 2008 054 896.0 vom 18.12.2008: HPA14253 DE – „MJ II-Druckverlustverteilung”;
• 4. DE 10 2008 054 897.9 vom 18.12.2008: HPA14263 DE -„MJ II-Schichtenlose Hilfsstoffzugabe”;
• 5. DE 10 2008 054 898.7 vom 18.12.2008: HPA14265 DE – „MJ II-DoS-TE-Geometrie”;
• 6. DE 10 2008 054 899.5 vom 18.12.2008: HPA14310 DE – „MJ II-Verteilrohrlochplattendicke”;
• 7. DE 10 2009 027 013.2 vom 18.06.2009: HPA14466 DE – „MJ II-W-STA”; und
• 8. DE 10 2009 027 721.8 vom 15.07.2009: HPA14569 DE – „MJ II-W-STA (Dosierrohr)”.

With regard to the constructional and functional design of the means 19 . 19.1 Reference is made to the following eight German patent applications of the applicant, the disclosure contents of which are hereby made the subject of the present description:

• 1. DE 10 2008 054 893.6 of 18.12.2008: HPA14251 EN - "MJ II-3 columns";
• Second DE 10 2008 054 894.4 dated 18.12.2008: HPA14252 EN - "MJ II EdgeModule";
• Third DE 10 2008 054 896.0 dated 18.12.2008: HPA14253 EN - "MJ II pressure loss distribution";
• 4th DE 10 2008 054 897.9 dated 18.12.2008: HPA14263 EN - "MJ II-Slat-free adjuvant addition";
• 5th DE 10 2008 054 898.7 dated 18.12.2008: HPA14265 EN - "MJ II-DoS-TE-Geometry";
• 6th DE 10 2008 054 899.5 dated 18.12.2008: HPA14310 EN - "MJ II distribution well plate thickness";
• 7th DE 10 2009 027 013.2 dated 18.06.2009: HPA14466 EN - "MJ II-W-STA"; and
• 8th. DE 10 2009 027 721.8 dated 15.07.2009: HPA14569 EN - "MJ II-W-STA (dosing tube)".

The in the 1 to 7 Headbox according to the invention, at least partially illustrated 1 is particularly suitable for use in a machine for producing a fibrous web 3 , in particular paper or board web, of at least one pulp suspension 2 ,

In summary, it should be noted that a headbox of the type mentioned above is improved by the invention so that the aforementioned disadvantages of the prior art as far as possible, preferably completely eliminated. In this case, the pressure loss for preferably uniform distribution of the pulp suspension is distributed as low as possible and optimal. Also, the energy consumption of the headbox is significantly reduced, improves the stability of the fiber orientation (transverse) profile and reduces the consumption of chemicals, in particular retention agents.

LIST OF REFERENCE NUMBERS

1

headbox

2

Pulp suspension (arrow)

3

Fibrous web

4

feeder

4.1

transverse distribution

Q4

cross-section

4.Q _max

Largest cross-sectional area

4.Z

Intake

5

distribution pipe

5.F

total area

5.L

length

6

flow channel

6.D.

Channel diameter

6.Q

Channel cross section

7

intermediate channel

7.L

Free intermediate channel length

7.Q

cross-section

7.Q _free

Free cross-sectional area

8th

Turbulence generator

9

flow channel

10

Machine width chamber

11

headbox

12

die gap

13

cover

14

inlet chamfer

15

Constant expansion

15.1

cone

16

Leap-like extension

16.1

increment

16.2

increment

17

Leap-like extension

17.1

increment

18

diffuser

19

medium

19.1

injector

19.H

height

19.L

length

20

Fluid (arrow)

20.T

Fluid partial flow (arrow)

21

Zudosierkanal

21.D

diameter

21.M

Opening centerline

21.O

Zudosierkanalöffnung

21.Q

Circular cross-sectional area

22

supply channel

22.D

diameter

22.Q

Circular cross-sectional area

23

Removable component

23.1

folding part

23.QR

Right-angled cross-section

24

articulation

A

Vertical distance

B

Width (arrow; double arrow)

C

of impact

D

distance

dp

pressure drop

N

Natural number

p ₁

First pressure loss

p ₂

Second pressure loss

p _s

System pressure loss

Q

Aspect ratio

R

Flow direction (arrow)

S

column

S1 to S4

column levels

TB

pitch width

Y

Width direction (arrow)

Z

row

Z1 to Z5

row

α

cone angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19843729 A1 [0002]
• DE 10208610 A1 [0005]
• DE 102008054898 [0021, 0066, 0081]
• DE 102008054893 [0081]
• DE 102008054894 [0081]
• DE 102008054896 [0081]
• DE 102008054897 [0081]
• DE 102008054899 [0081]
• DE 102009027013 [0081]
• DE 102009027721 [0081]

Claims (14)

Headbox ( 1 ) for a machine for producing a fibrous web ( 3 ), in particular a paper, board or packaging paper web, from at least one pulp suspension ( 2 ), with at least one pulp suspension ( 2 ) and a transverse distribution tube ( 4.1 ) comprehensive delivery device ( 4 ), with a downstream and a plurality of flow channels arranged in rows (Z; Z1 to Z5) and in columns (S) (US Pat. 6 ) distribution well plate ( 5 ), with a downstream thereto, across the width (B) of the headbox ( 1 ) extending intermediate channel ( 7 ), with a downstream turbulence generating means ( 8th ) having a multiplicity of flow channels arranged in rows (Z) and in columns (S; S1 to S4) ( 9 ), and with a turbulence generating means ( 8th ) immediately adjacent and a nozzle gap ( 12 ) headbox ( 11 ), characterized in that a system pressure loss (p _s ) is provided which essentially consists of a first pressure loss (p ₁ ) between the supply device (p ₁ ) 4 . 4.1 ) and the intermediate channel ( 7 ) and a second pressure loss (p ₂ ) in the turbulence generating means ( 8th ), wherein the first pressure loss (p ₁ ) assumes a value in the range from 15 to 85%, preferably from 25 to 85%, in particular from 40 to 85%, that between the distribution well plate ( 5 ) and the turbulence generating means ( 8th ) arranged intermediate channel ( 7 ) a free intermediate channel length ( 7.L ) of ≥ 50 mm, preferably of ≥ 120 mm, in particular of ≥ 200 mm, and in that the cross-sectional ratio (Q) between inlet ( 4.Z ) and intermediate channel ( 7 ) assumes a value in the range from 0.1 to 2, preferably from 0.15 to 1.5, in particular from 0.2 to 1. Headbox ( 1 ) according to claim 1, characterized in that the second pressure loss (p ₂ ) in the turbulence generating means (p ₂ ) 8th ) assumes a value in the range from 0.1 to 1.5 bar, preferably from 0.2 to 1.0 bar, in particular from 0.3 to 0.5 bar. Headbox ( 1 ) according to claim 1 or 2, characterized in that the distribution well plate ( 5 ) with hydraulic elements for pressure recovery, such as diffusers ( 18 ), Stage diffusers or short diffusers. Headbox ( 1 ) according to one of the preceding claims, characterized in that the at least one of the feeding device ( 4 . 4.1 ) supplied pulp suspension ( 2 ) excluding the downstream flow channels ( 6 ) of the distribution well plate ( 5 ) is supplied. Headbox ( 1 ) according to one of the preceding claims, characterized in that in the intermediate channel ( 7 ) several in the width direction (Y) of the headbox ( 1 ) spaced apart means ( 19 . 19.1 ) for the preferably controllable metered addition of a fluid ( 20 ) in partial fluid streams ( 20.T ) into the at least one pulp suspension ( 2 ), whereby the single item ( 19 . 19.1 ) in each case a plurality of a respective Zudosierkanalöffnung ( 21.O ) and aperture centerline ( 21.M ), opening at different heights and having a common supply channel ( 22 ) associated Zudosierkanäle ( 21 ), Headbox ( 1 ) according to claim 5, characterized in that the impact point (C) of the opening center line ( 21.M ) of the individual metering channel opening ( 21.O ) on the turbulence generating means ( 8th ) approximately centrally, preferably in the middle between the two column planes (S1 to S4) of two adjacent flow channels ( 9 ) lies. Headbox ( 1 ) according to claim 5 or 6, characterized in that the Zudosierkanalöffnung ( 21.O ) of the agent ( 19 . 19.1 ) for the preferably controllable metered addition of the fluid ( 20 ) in partial fluid streams ( 20.T ) at least one pulp suspension ( 2 ) to the turbulence generating means ( 8th ) has a vertical distance (A) in the range of 2 to 50 mm, preferably from 3 to 40 mm, in particular from 5 to 20 mm. Headbox ( 1 ) according to claim 5, 6 or 7, characterized in that the respective means ( 19 ) for the preferably controllable metered addition of the fluid ( 20 ) in partial fluid streams ( 20.T ) into the at least one pulp suspension ( 2 ) an injector ( 19.1 ). Headbox ( 1 ) according to any one of claims 5 to 8, characterized in that the fluid ( 20 ) of water, in particular white water or clear water, or of at least one pulp suspension ( 2 ) whose concentration is different from the average concentration of at least one in the headbox ( 1 ) flowing pulp suspension ( 2 ) differs. Headbox ( 1 ) according to one of the preceding claims, characterized in that the transverse distribution tube ( 4.1 ) in the flow direction (R) of the pulp suspension ( 2 ) tapered cross-section ( Q4 ) and that the transverse distribution pipe ( 4.1 ) in the region of its largest cross-section ( Q4 ) to a supply line ( 25 ) for the pulp suspension ( 2 ) connected. Headbox ( 1 ) according to claim 10, characterized in that the transverse distribution pipe ( 4.1 ) in the region of its preferably smallest end-side cross section ( Q4 ) at least one removable component ( 23 . 23.1 ), wherein the removable Component ( 23 ., 23.1 ) preferably has a rectangular cross-section ( Q4 ) owns. Headbox ( 1 ) according to claim 10 or 11, characterized in that the component ( 23 ) as a folding part ( 23.1 ) and by means of at least one articulated connection ( 24 ) and associated attachment with the transverse distribution tube ( 4.1 ) connected is. Headbox ( 1 ) according to claim 10, 11 or 12, characterized in that the component ( 23 . 23.1 ) is designed as a cleaning access and / or as a sampling point. Machine for producing a fibrous web ( 3 ), in particular a paper, board or packaging paper web, from at least one pulp suspension ( 2 ), characterized in that it comprises at least one headbox ( 1 ) according to one of the preceding claims.

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