Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
  • D21F1/02—Head boxes of Fourdrinier machines
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
  • D21F1/02—Head boxes of Fourdrinier machines
  • D21F1/022—Means for injecting material into flow within the headbox

Definitions

• Headbox for a machine for producing a fibrous web
• the invention relates to a headbox for a machine for producing a fibrous web, in particular paper or board web, from at least one pulp suspension, comprising a feeding device feeding the at least one pulp suspension, having a downstream and a plurality of channels arranged in rows and in columns Distribution well plate, with a lying downstream, across the width of the headbox extending intermediate channel with a plurality of spaced in the width direction of the headbox means for preferably controllable / metered metering of a fluid in fluid partial streams in the at least one pulp suspension, he id he inter kan al Two compensation areas with a measured in the flow direction total compensation length, in which a compensation flow across the flow direction and across the width of the intermediate channel away is possible, and w at least one sectional area having a section length measured in the flow direction, in which the means for preferably controllable metering of a fluid in fluid sub-streams are arranged in the at least one pulp suspension to also section the flow across the width of the intermediate channel and comprises wherein the single means
• Such a headbox is known for example from the document DE 44 16 909 A1.
• This document DE 44 16 909 A1 discloses a headbox for a paper machine with a feed device for the pulp suspension, a downstream adjoining provided with a plurality of channels guide means, a downstream thereto, extending over the width of the headbox mixing chamber with a plurality of across the Headbox distributed, extending substantially in the direction of flow partitions and distributed across the headbox feeders for a zuzumischendes fluid with Zumischö réelleen downstream of another, a Learnzah l of channels having guide means and a subsequent, an outlet gap for the stock suspension forming nozzle chamber.
• the supply means for the admixed fluid extend into the mixing chamber and the sectional area formed by the partitions in the mixing chamber begins in the region of the openings to where it extends substantially in the flow direction to the second guide means.
• the headbox shown in this document forms a system which can meet the particular technological requirements for a good mixing quality of pulp suspension and fluid, a sufficient volume flow stability, a low effective width and a low mapping offset more or less well or only partially.
• the mixing quality of pulp suspension and fluid is usually positively influenced by a good pre-distribution of the media in the height direction, by a large turbulence intensity in the media and by a long mixing distance for the media.
• transverse flows are induced in the intermediate channel.
• These transverse flows occur primarily in the first open part of the intermediate channel, ie before the means for preferably controllable metering of a fluid in partial fluid streams into the at least one pulp suspension. If this first open part of the flow is too high, a large cross-flow velocity and / or a congestion effect is generated between the means for preferably controllable metering of a fluid in partial fluid streams into the at least one pulp suspension.
• transverse flows in the headbox nozzle are generated in turn, which ultimately lead to errors in the fiber orientation in the fibrous web to be produced.
• the total compensation length formed from the at least two compensation areas and measured in the flow direction has a value in the range of 30 to 1, 500 mm, preferably from 100 to 500 mm, in particular from 150 up to 300 mm.
• the inventive design of the headbox of the type mentioned provides a most extensive, preferably complete avoidance of the disadvantages of the prior art and a much improved fulfillment of particular technological requirements.
• the headbox according to the invention has a technically simple and reliable Zudosiersystem, which is also still inexpensive and technically easy to perform.
• the indicated and measured in the flow direction total compensation length has a very positive effect on the required good to very good mixing quality of pulp suspension and fluid, the desired low effective width and the necessary low mapping offset.
• the expert well known separation element in particular a blade be arranged. If several separating elements, in particular slats in the headbox of the head box according to the invention may be arranged, they may have different lengths and possibly also different properties, such as surface contours and the like.
• the trained as a metering means for preferably controllable metered addition of the fluid in partial fluid streams in the at least one pulp suspension preferably has a counter to the flow direction of the at least one pulp suspension directed leading edge at an angle of 60 to 90 °, preferably from 75 to 85 °, in particular of about 80 °, to the flow direction of the at least one pulp suspension.
• the compensating part length formed between the distribution tube perforated plate and the means for preferably controllable metering of the fluid in partial fluid streams into the at least one fibrous suspension is preferably a mathematically averaged value.
• the compensation part length formed between the means for preferably controllable metering of the fluid in the fluid part in the at least one pulp suspension of the distribution well plate and the turbulence generating means preferably has a value in the range of 5 to 150 mm, preferably from 10 to 50 mm, in particular of 15 mm. In this way, in particular the desired directional and calm flow can be realized before the metering.
• the length e of the metering blade provided in the direction of flow of the at least one pulp suspension is preferably in a ratio to preferably metered / controllable metering of the fluid in partial fluid streams into the at least one pulp suspension and the length of the intermediate channel from 1: 1, 25 to 1: 5, preferably from 1: 1, 5 to 1: 3.
• These value ranges have an effect, in particular, on the desired low effective width due to a directed and steady flow upstream of the metering point and low transverse flows at the metering point.
• the trained especially as dosing means for preferably adjustable / controllable metering of the fluid in partial fluid streams in the at least one pulp suspension is preferably angeord net on the lower wall and / or on the upper wall of the intermediate channel.
• This embodiment is particularly useful in high-line turbulence generating means to limit the Fluidzuström füren in the individual fluid supply line.
• the two walls of the intermediate channel may be at least partially parallel to each other, convergent, divergent, stepped or spherically curved and arranged.
• the arrangement of the means for preferably controllable metered addition in at least one row is also possible. If the means for preferably regulatable / controllable metering are arranged in several rows, then they can also be arranged offset from one another.
• the medium which is in particular designed as a metering blade, for preferably metered addition of at least one metal, such as, for example, a stainless steel, titanium or bronze, or a plastic, such as a thermosetting plastic, may be made of a thermoplastic , consist of a (hard) rubber, a GRP, CFK or similar.
• a plastic version in particular the materials polyamide (PA), polyphenylsulfone (PPSU), Teflon (PTFE), polyoxymethylene (POM) are advantageous.
• the distribution well plate is preferably of a length that is> 0.5 divisional area, and preferablyj d each Te un g S f
• This inventive design of the headbox of the type mentioned allows the construction and operation of a compact headbox with a comparison with the known headboxes of the prior art significantly reduced pressure drop in the distribution well plate so that it has a process technology sufficient operating stability even over an extended operating range having.
• the Inflow rate of the pulp suspension in the intermediate channel of the headbox by at least one diffuser desirably reduced.
• the division area must be small in order to control the deflection effects as well as the hydraulic function of a diffuser in a small-diameter flow area.
• the length of the distribution well plate is still a sufficient "guide length", so that an undesirable transverse component to the machine direction in the effluent from the distribution well plate pulp suspension can be completely avoided.
• the division surface of the distribution well plate in a preferred embodiment assumes a value in a range of ⁇ 4,000 mm 2 , preferably of ⁇ 2,500 mm 2 , in particular from 200 to 1, 000 mm 2 , at. These value ranges contribute significantly to a compact construction of the headbox.
• the single channel of the distribution well plate preferably has a round channel cross-section with a channel diameter and the average channel diameter of the single channel of the distribution well plate and the length of the distribution well plate are ideally in a ratio of 1: 2 to 1:10, preferably 1: 3 to 1: 8, in particular from 1: 4 to 1: 5. These value ranges allow improved stability of the headbox in an optionally larger operating window.
• the diffuser formed in the single channel of the distribution well plate preferably has at least one abrupt extension, in particular a step jump, and / or at least regionally a continuous extension, in particular a cone with a cone angle of ⁇ 30 °. Also, the diffuser formed in the single channel of the distribution well plate preferably has at least two extensions described above. These designs contribute significantly to the desired or necessary smaller Inflow velocity of the pulp suspension in the intermediate channel of the headbox and an advantageous pressure recovery at.
• the at least one pulp suspension fed to the feed device is preferably fed exclusively to the downstream adjoining channels of the distribution well plate.
• the feeder and the channels of the distribution well plate are preferably dimensioned such that the flow rate of the at least one pulp suspension in the feeder and the average flow rate of the at least one pulp suspension in the channels of the distribution well plate are in a ratio of 1: 2 to 1: 4 ,
• the fluid preferably consists of water, in particular clear water, or of a pulp suspension, in particular white water, the concentration of which differs from the average concentration of the at least one pulp suspension in the headbox.
• the headbox according to the invention is outstandingly suitable for use in a machine for producing a fibrous web, in particular paper or board 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
• Figure 1 is a vertical longitudinal sectional view of an embodiment of a headbox according to the invention for a machine for producing a fibrous web of at least one pulp suspension;
• FIG. 2 is a partial view of that shown in FIG.
• Headbox for a machine for producing a fibrous web from at least one pulp suspension
• FIG. 3 shows a detailed detail of the headbox 1 shown schematically in FIG. 1;
• Figure 4 is a vertical longitudinal sectional view of a Verteillochlochplatte the head box according to the invention for a machine for producing a fibrous web from at least one pulp suspension with different channel cross-sections.
• 1 shows a vertical longitudinal section of an exemplary embodiment of a headbox 1 for a machine for producing a fibrous web 3 from a pulp suspension 2.
• the illustrated headbox 1 can of course also be configured as a multilayer headbox, which uses at least two different pulp suspensions for producing the fibrous web 3 ,
• the fibrous web 3 may in particular be a paper, board or tissue web.
• the headbox 1 has a feed device 4 which feeds a pulp suspension 2, for example in the embodiment of a transverse distributor tube 5 or a rotary distributor (not illustrated) with a multiplicity of tubes.
• the feed device 4 is followed downstream by a distribution well plate 6, which has a plurality of channels 7 arranged in rows Z and in columns S (see FIG.
• the at least one of the feed device 4, 5 fed pulp suspension 2 may be supplied to the downstream only adjacent channels 7 of the distribution well plate 6.
• the individual means 9 for preferably controllable metering comprises in each case a plurality of metering channels 18 having a respective metering channel opening 18.1 and opening at different heights, connected to a common supply channel 19 (see FIG.
• the intermediate channel 8 comprises two compensation regions C.1, C.2 with an overall compensation length CL measured in the flow direction R (arrow), in which a compensation flow transversely to the flow direction R (arrow) and across the width B (arrow) of the intermediate channel 8 is possible, and a sectional area D with a measured in the direction of flow R (arrow) section length DL, in which the means 9 for preferably controllable / metered addition of a fluid 10 (arrow) in partial fluid streams 10.T (arrow) in the at least one Fibrous suspension 2 are arranged to also section the flow across the width B (arrow) of the intermediate channel 8 across.
• a turbulence generating means 1 1 Downstream of the intermediate channel 8 is a turbulence generating means 1 1 having a plurality of flow channels 12 arranged in rows Z and in columns S.
• the pulp suspension 2 in the turbulence generating means 11 is moved into Divided pulp suspension sub-streams and after exiting the turbulence generating means in a machine-wide chamber 13 in a design of a nozzle gap 15 having headbox 14 merged again to allow the formation of a machine-wide fibrous web 3.
• the flow channels 6 are preferably formed in a known manner 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.
• the expert well known and not explicitly illustrated separating element in particular a La mel le angeord net is n. If several separating elements, in particular lamellae, are arranged in the headbox nozzle 14, they can, for example, be subject to constant delays and, for example, even in an extremely variable manner, such as surface contours and the like , exhibit.
• the headbox 14 may optionally be provided on the outlet side with at least one aperture 16 indicated by dashed lines.
• the total compensation length CL formed from the at least two compensation areas C.1, C.2 and measured in the flow direction R (arrow) has a value in the range from 30 to 1, 500 mm, preferably from 100 to 500 mm, in particular from 150 to 300 mm.
• the means 9 designed as a metering blade 9.1 for preferably controllable metered addition of the fluid 10 (arrow) into partial fluid streams 10T (arrows) into the at least one pulp suspension 2 (see Figure 3) has an opposite to the flow direction R (arrow ) of the at least one pulp suspension 2 directed leading edge 23 which at an angle ⁇ of 60 to 90 °, preferably from 75 to 85 °, in particular from about 80 °, to the Flow direction R (arrow) of at least one pulp suspension 2 extends.
• the compensating part length C.2 which is formed between the means 9 for preferably controllable metering of the fluid 10 (arrow) into partial fluid streams 10 T (arrows) into the at least one pulp suspension 2 (see FIG. 3) and the turbulence generating means 11 .L a value in the range of 5 to 150 mm, preferably from 10 to 50 mm, in particular of 15 mm.
• the arranged in the rows Z and in the columns S channels 7 of the distribution well plate 6 have at least partially at least one known in the art diffuser. And the distribution hole plate 6 has a length
• FIG. 2 shows a partial view of the headbox 1 shown in FIG. 1 for a machine for producing a fibrous web from at least one pulp suspension according to the view arrow A.
• the distributor well plate 6 has three rows Z1 to Z3 on channels 7 and several columns on channels 7 However, only four columns S1 to S4 are shown on channels 7.
• F of the distribution tube 6 and the total number of channels 7 of the distribution well plate 6 arranged in the rows Z1 to Z3 and in the columns S, takes a value in a range of ⁇ 4,000 mm 2 , preferably of ⁇ 2,500 mm 2 , in particular from 200 to 1, 000 mm 2 , at.
• the distribution well plate 6 itself has an open area 6.0 of> 30%, preferably of> 40%, in particular of> 50%, wherein the open area 6.0 of the distribution well plate 6, the quotient of the downstream total area 7.F in the rows Z1 to Z3 and arranged in the columns S1 to S4 channels 7 of the Verteilrohrlochplatte 6, indicated only for a flow channel 7, and the downstream total area 6.F is the Verte il rlochplate 6.
• the total flow area 6 of the distribution pipe hole 6 is usually the same as the upstream total entry area of the headbox intermediate chamber.
• the individual channel 7 of the distribution well plate 6 at least initially has a round channel cross section 7.Q with a channel diameter 7.D.
• the illustrated channels 7 of the distribution well plate 6 have an abrupt extension 17, in particular a step jump 17.1 of the respective initial round channel cross section 7.Q on an ultimately rectangular, in particular square channel cross section 7.Q on.
• the mean channel diameter 7. DM of the channel 7 of the distribution well plate 6 and the length 6.L (arrow) of the distribution well plate 6 (see Figure 1) lie in one Ratio of 1: 2 to 1:10, preferably from 1: 3 to 1: 8, in particular from 1: 4 to 1: 5.
• FIG. 3 now shows a fragmentary detailed representation of the headbox 1 shown schematically in FIG.
• the means 9 designed as a metering blade 9.1 for preferably controllable metering of a fluid 10 (arrow) into partial fluid streams 10.T (arrows) into the pulp suspension 2 each comprise a plurality of metering channel length and metering channel opening 18.1 having different heights and opening
• all of the metering ports 1 8.1 of the metering channels 1 8 of the metering device 9.1 designed as means 9 for preferably controllable / metered metering of the fluid 10 (arrow) in partial fluid streams 10.T (arrows) in the open Pulp suspension 2 at different heights.
• the means 9 formed as a metering blade 9.1 for preferably controllable metered addition of a fluid 10 (arrow) into partial fluid streams 10.
• T (arrows) into the pulp suspension 2 is described in the German patent application DE 10 2008 054 898.7 of 18.12.2008 (Applicant's file reference : HPA14265 DE and Applicant's Working Title: "MJ M-DoS-TE Geometry”), the disclosure of which is hereby incorporated herein by reference.
• the means 9 for preferably controllable metered addition have a preferably the same or approximately equal pitch T (arrow) in the width direction of the headbox 1 in the range of 10 to 100 mm, preferably 25, 33, 50 or 66 mm.
• the means 9 designed as a metering blade 9.1 for preferably controllable metered addition of the fluid 10 (arrow) into partial fluid streams 10T (arrows) is arranged in the at least one pulp suspension 2 on the lower wall 8.1 of the intermediate channel 8.
• the means 9 for preferably controllable / metered metering could also be arranged on the upper wall 8.2 of the intermediate channel 8.
• the two walls 8.1, 8.2 of the intermediate channel 8 are arranged parallel to each other in the present case; However, they could also only partially executed parallel to each other, parallel, convergent, divergent or spherical curved and arranged.
• the means 9 for preferably controllable metered addition are arranged in a row; However, they can also be arranged in at least two rows, wherein they can also be arranged offset from each other.
• FIG. 4 shows a vertical longitudinal section of a distribution well plate 6 of the head box 1 according to the invention for a machine for producing a fibrous web from at least one pulp suspension with different channel cross sections 7.Q.
• the distribution well plate 6 has five rows Z1 to Z5 on channels 7 and a plurality of columns S on channels 7. All channels 7 have a consistently round Channel cross-section 7.Q on, but in different shapes and configurations.
• all channels 7 are provided on the inlet side with a respective intake chamfer 20 known to those skilled in the art.
• the channels 7 of the two upper lines Z4, Z5 have initially a constant channel cross section 7.Q, which ultimately experiences a continuous extension 21, in particular a cone 21 .1 with a cone angle ⁇ of ⁇ 30 °.
• the channels 7 of the middle row Z3 initially again have a constant channel cross-section 7.Q, the last one I two jump-like extensions 1 7, in particular increments 17.1, 17.2 learns.
• the channels 7 of the two lower lines Z1, Z2 initially again have a constant Kanalquersch n itt 7.Q, the lastl I learn only a spru ngartige extension 17, in particular a step jump 17.1.
• Each individual channel 7 of the distribution well plate 6 thus has at least initially a round channel cross section 7.Q with a channel diameter 7.D and then ultimately forms at least one diffuser 22 due to at least one extension 17, 21.
• the mean channel diameter 7. DM of the channel 7 of the distribution well plate 6 and the length 6.L of the distribution well plate 6 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 features of the headbox 1 embodiments described in FIGS. 1 to 4 can also be combined, at least partially, with one another in a manner that is obvious to the person skilled in the art.
• the respective headbox 1 of Figures 1 to 4 is particularly suitable for use in a known to the skilled machine for the production a fibrous web 3, in particular paper or board web, of at least one pulp suspension 2.
• the fluid 1 0 (arrow) flowing through the respective headbox 1 of FIGS. 1 to 4 consists at least of water, in particular white water or clear water, or of at least one fibrous suspension whose concentration is different from the average concentration of the at least one in the headbox 1 flowing pulp suspension 2 is different.
• a headbox of the type mentioned is improved by the invention so that a trouble-free operation of the headbox even at a low pressure drop in the at least one pulp suspension is possible.
• a process-technologically adequate operational stability over an extended operating range is achieved with a still compact construction of the headbox.

Landscapes

• Paper (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=43719484

Family Applications (1)

Country Status (4)

Families Citing this family (8)

Family Cites Families (4)

• 2010
  • 2010-02-03 DE DE201010001541 patent/DE102010001541A1/de not_active Withdrawn
  • 2010-12-15 EP EP10794963A patent/EP2531645A1/de not_active Withdrawn
  • 2010-12-15 WO PCT/EP2010/069688 patent/WO2011095252A1/de active Application Filing
  • 2010-12-15 CN CN2010800660406A patent/CN102822416A/zh active Pending

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events