CA2045038C - Headbox for papermaking machine with more uniform flow - Google Patents
Headbox for papermaking machine with more uniform flow Download PDFInfo
- Publication number
- CA2045038C CA2045038C CA002045038A CA2045038A CA2045038C CA 2045038 C CA2045038 C CA 2045038C CA 002045038 A CA002045038 A CA 002045038A CA 2045038 A CA2045038 A CA 2045038A CA 2045038 C CA2045038 C CA 2045038C
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- Canada
- Prior art keywords
- headbox
- pulp
- section
- mixer
- pulp suspension
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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
- D21F1/028—Details of the nozzle section
-
- 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
- D21F1/026—Details of the turbulence section
-
- 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
- D21F1/08—Regulating consistency
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- Sewing Machines And Sewing (AREA)
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Abstract
A headbox for a papermaking machine with an outlet slot that distributes pulp suspension over the working width of the papermaking machine. For controlling operating parameters of throughput, pulp density and fiber quality of the suspension over the width of the machine, the headbox having a plurality of individual sections across the width of the machine.
Each section has respective channels therethrough for passing pulp suspension. At least one connection at each section is to a controllable supply of pulp suspension where the operating parameters of that supply are controllable. Only separate operating parameter controlled streams pass through the sections of the headbox. Operating parameter control devices may deliver adjusted streams to a mixer upstream of the headbox channels. The mixer may also have individual sections across the width of the machine. The headbox has a common outlet nozzle downstream of the individual channels and the individual sections, where the pulp suspension stream from channels with controlled suspension parameters and from any channels without controlled suspension parameters are reconstituted to have the desired suspension operating parameters.
Each section has respective channels therethrough for passing pulp suspension. At least one connection at each section is to a controllable supply of pulp suspension where the operating parameters of that supply are controllable. Only separate operating parameter controlled streams pass through the sections of the headbox. Operating parameter control devices may deliver adjusted streams to a mixer upstream of the headbox channels. The mixer may also have individual sections across the width of the machine. The headbox has a common outlet nozzle downstream of the individual channels and the individual sections, where the pulp suspension stream from channels with controlled suspension parameters and from any channels without controlled suspension parameters are reconstituted to have the desired suspension operating parameters.
Description
HEAD$OX FOR PAF$RMAKINC~ MACHINE
WITH MORE UNIFORM FLOW
The present invention relates to a headbox or breaatbox for a papermaking machine, and particular-ly to means for adjusting the pulp density of the pulp xuspen~ion over the working width of the headbOx or the machine width.
One such hsedbox is known from Federal Republic of Germany patent 35 14 554. Such a headbox is fntended to make the pulp ~3uspenr3ion uniform over the entire cross machine width of the pulp outlet from the headbox. At the downstream end of the flow path of the suspension, it should be made uniform in front of the discharge or outlet slot from the headbox. The uniformity sought is such that both the denstity of the pulp. that is the weight of fiber content per unit volume, and the oriunta~tion of the fibers in the pulp ere constant over the width of the pulp outlet from the headbox. Both of these qualities are important prerequisites for the finished paper being produced by the paperma~king machine, in order to have a proper weight per unit area and a proper thicknea;~ profile over the entire cross machine width of the web and so that the paper lies flat and does not tend to curl.
2o~~oaa _Z_ During operation of the pspermaking machine, numerous disturbing factors interfere with the satisfaction of the two uniformity requirements. Thence factors include temperature variations, pressure variations and manufacturing tolerances in the headbox and in the pulp suspension, for example.
The above notad German patent is concerned with s~olvinq tha same problems as are noted above, which are also the problems to be solved by the present invention, That patent recognizes that it is important to both maintain the density of the fibers in the pulp suspension over the width of the pulp outlet and also to control the fiber orientation so that, if it is possible, no transverse !low will occur iri the outlet channel. The oerman patsnt proposes that the density of the pulp suspension be changed locally, that is that the density of the pulp suspension be changed at given places across the machine width, as required. However, the patent does not provide what is believed by the present inventors to be the best solution to this problem.
It is also known to vary the width of the distcharge slot, that is the height of the outlet open~.ng at the disGhar9e slot. One way to do that is by tha use of threaded spindles for swingi»fl or bending one lip, and partfcularly the upper lip that defines the discharge slot. For instance, see Federal Republic ~f Germany patent 29 42 9s6 , corresponding to U.B.
Patent x,326,916, or Federal Republic of Germany publi$hed Application OS 35 35 849. This adjustment of the w$dth of the discharge slot enables local variation of the throughput of the suspension, 11t the same time, however, the direction of suspension flow is also lOCally affected, which affects the orientation of the fibers in the suspension. The local narrowing of the outlet slot causes a different flow direction in the fibers at the narrowed places of the slot than along the remainder of the diaeharge slot. Although the density of the pulp can be made uniform over the width of the pulp outlet by the so-called displacement control, the fibQr orientation, which may have been la good, is undesirably again disturbed. Although the inventors have recognized that the last two above noted Germnn patent applications proceed fundamentally in the correct direction, nonetheless, they do not appear to be able to independently control the two parameters of 15 the density of the pulp and the fiber orientation.
it is an object of the invention to provide a headbox or breastbox which enables independent control of each of the parameters of the den$ity of the ~0 pulp suspension and the fiber orientation in the pulp suspension in a practical and reliable manner.
The concept of the invention involves sectionalizing the headbox into individual sections across the machine width, which is an already known 25 design, and also to feed individually controllable, partial streams or section streams of the pulp suspension to the individual sections of the headbox.
The operating parameters of each individual one of the parbiel streams, particularly their throughput, pulp 30 density and fiber quality, can be individually adjusted without adjusting any of the parameters of the other partial streams or along with adjusting those parameters in the other partial streams differently.
Each of the section streams feeds a respective separate section of the headbox. Each of the section streams is preferably conducted separately through the headbox, and the streams are combined with each other only toward the outlet nozzle from the headbox.
Each section stream is formed by bringing together two separate streams for that section, of which at least one stream in some embodiments, and in other embodiments both streams have their above noted parameters Controlled. Depending upon the mixture ratio and pulp concentration and the flow rate of these control streams, the nature of each of the section streams in each individual section can be very preaidely established.
The headbox of the present invention distributes pulp xuspension over the working width of the papermaking machine and ejects the suspension into the inlet slot or nap of a web forming section, for expmgle.
The headbox includes a pulp suspension guide device through which peas a plurality of holes or channels that define the channels and that extend from the upstream to the downstream sides of the headbax.
The holes or channels are in a Selected array across the width of the headbox. There is a discharge nozzle also extending across the width of the machine with a discharge or outlet slot for distributing the pulp suspension.
Upstream of the headbox in the pulp suspension flow path are located means far adjusting the pulp density of the pulp suspension over the working width of the machine. The individual BeCtions of the haadbox are formed by partitions which divide the headbox into individual separate sections over the cro** machine width. Each individual section has at least one feed line channel or hole for feeding through !t a partial r~tream or section stream of the pulp su*pen*ion.
A mixer is arxanged upstream of or in front of the feed line of the headbox. In one embodiment, the mixer has at least two connections for introducing respective parameter controlled suspension streams, having predetermined operating parameters, such as throughput, pulp density and fiber quality. In other embodiments, fewer than or only one of the connections and its suspension stream i$ controlled. But through merely that control, the final mixed output from the discharge slot is controlled.
Other objects and features of the present invention will become apparent form the following de*cription of preferred embodiments of the invention considered in connection with the accompanying drawinq~~ in which:
gig, is schematically illustrates one pulp sua~psnsion flow mixing apparatus, and shows means for mixing flows that are supplied to individual sections o~ the headbox;
his. 1b illustrates an alternate pulp suspension flow mixting apparatu9;
-s-Fig. 2a is a aide elevationai cross-sectional view through one individual section of 8 B rat embodiment of a headbox, with a plurality of individual pulp flow channels through it;
gig. ~b fs a plan cross-Sectional view of the headbox of Fig. 2s showing individual, headbox sections and showing a plurality of channels through the haadbox arrayed across the width of the machine and in each of the individual headbox sections~f P'ig. 3a illustrates a second headbox embodiment Like that in Fig. 2a and 2b and schematically depicts the mixer which delivers parameter controlled suspension to the headbox;
~'ig. 3b is an end view of the mixer of Fiq. 3a, seen in the direction of arrow A in Fig. 3a, showing individual deliveries of mixed suspension to tht mixer for subseciuent delivery to the headbox;
Fig. 3c is a view in the same direction as l~fg. 3b, showing a partitioned mixer embodiment for individual deliveries of mixed suspension to the headbox;
F'ig. 4a is a side elevational cross-sectionol view through a third embodiment of ~ headbox, where the individual sections are narrowed channels a5 through the headbox and there arQ a plurality of thosQ
channels in each section, which are arrayed vertically acroga the headbox;
Fig. 4b is a plan cross-sectional partial view of the headbox of Fig. 4a showing the partitioned headbox, showing the deliveries of different mixtures of pulp suspension to the headbox and Showing the individual channel sections arrayed across the machine width Fig. ~c is an alternate fourth embodiment Of the headbox and mixer of Fig. 4b, wherein the mixer has individual partitioned sections, each for transmitting to the headbox a respective mixture of pulp suspension;
gig. Sa is a side elevational crosa-seationnl view of a fifth embodiment of a haadbox and mixer, showing two longitudinally spaced areas of partial channel sactions~ in the headbox;
i~ig. Sb is a plan cross-sectional view of the headbox of Fig. 3a, showing the individual sections of the mixer across the width of the headbox;
Fig. 6a is a aide elevational cro~s-sectional view of a sixth embodiment of a headbox and mixer combination, wherein the mixer ist fed with a premixed partial stream which is mixed with a conventional supply of pulp suspen$ion;
Fig. 6b is an enlarged detail of P~iq. Gas ~'iQ. 6c is a rear view of the mixer of Fig.
6a, showing the suspension or material feed to the mixer;
Fig. 7 i~c a side elevational cross-sectionai view of a seventh embodiment of a headbox and mixer combination where the mixed partial sttreams are ~5 fad into a channel between the tube bundles through the haadbox;
his. 8a is a top view of an eighth embodiment of a mixer and headbox combination wherein the piuraiity of parameter controlled partial streams are fed to connections acrossc the top of the headbox past the introduction mixer;
Fig. 8b i$ a top view of the headboa and mixfr combination of Fig, 8a;
Fig. 9a is a side olevdtiona~l cross-goctional view of a ninth embodiment of a combination of headbox and mixer showing direct feeding of the conneadtions across controlled partial stream into one or more of the tube lines of the turbulence inserts of a suction of the headbox=
f'ig. 9b is rear view of the headbox of Fig.
1.0 9a in the direction of arrow C in Fig. 9a;
Fig, 10a is a side elevational cross-sectional view of an alternate, tenth embodiment of a headbox with direct feed of a controlled mixture partial stream into one or more of the tube lines;
Ffg, lOb i$ a plon longitudinal cross section of the headbox and mixer of Fib, l0af Fig, ila is a side elevational cross-seationai, fragmentary, view of an eleventh embodiment of a headbox showing feeding of the parameter controlled mixtuxe into the nozzle space downstream of the individual sections; and Fig. lib is a top view of the headbox of Fig. ila, In the pulp su~xpens~ion control apparatus shown in ~'ig, la, the mixer 20 delivers to the headbox, not shown in xig. la, a mixed stream 22 having the volume ~ and having the concentration CM of fiber material in the pulp suspension.
3~ Th8 mixer 20 is supplied by two separate pulp suspension streams which are brought together in 2fl45038 9 _ tha mixer. The first stream 2~ has the volume Qx and the fiber concentration CH. The second stream 26 has the volume QL and the fiber concentration CL.
The first pulp stream 24 is supplied from a ~tource, not shown, past the volumetric control, adjustable valve 28 that is controlled by flow rate controller 32. The second pulp str:am 26 is supplied from another source, dnd it is mixed with a separate pulp supply at the volumetric control, adjustable valve 1.0 34. The valve 3a is controlled by the flow rate controller 36. That controller, in turn, is supplied by the two liquid or suspension streams from the scparote pulp sources 38 and 42 which are mixed in the mixer at the controller 36. Adjustment of the valves 28 and 34 determines the volume ratios QH/QL. Also, by appropriate control over special pulp sources 38 and 42, it is possible to adjust the concentration CL of pulp suspension in pulp stream 26, therQby to adjust the !low rate and the fiber concentration in conduit 22.
An actual situation controlled by the control apparatus of Fig. la is now described. The arrangement shown in Fig, la just delivers a pulp su~tpansior, flow to a conduit 22 which i;~ connected to 2S ona of the individual sections of a headbox. As will be apparent below, there may be an individual one of the control apparatus shown in Fig. la for each of the individual sections of the headbox across the machine width, and each of those individual control apparatus shown fn P'ig, la can be operated independently.
wring a periodic quality control check of the paper web being produced or of the pulp $uspen$ion -lo-being dispensed by the headbox, it may be found that the weight per unit area profile, at the individual section across the width of the web, of the mixed pulp suspension which is supplied through mixer 20 in Fig.
S la and controlled by the control devices shown in Fig.
la, differs beyond an acceptable level from a desirQd value, either in flow volume QM or pulp ~euspansion aoncentrntion CM. Therefore, the pulp density of the suspension in the headbox must be suitably corrected at this section across the width of the headbox.
According to the invention, the adjustment can be made by varyfng the concentration CM of the individual section stream 22 that is controlled by the control apparatus shown in Fig. 1A. The necessary change in CM, that is dCji, can be determined from a previously prepared weight balance sheet. The resulting corrected concentration C~ is dependent exclusively upon the ratio of the control streamss QH/QL. The fiowthrough of theca two streams may be halted while the ratio adjustment is made. The corrected value of CM is used as a basis far ratio control to establish the dasir~ad value setting. The ratio control eats the new controi/flow ratio Q~/CM, in Fig. 1A this is accomplished by changing QL, e.g.
through valve 34 and through sources 3a and ~2.
~towevar, it ia~ important that the combined volumetric flow Q~ remain constant, so that the individual headbox section may be fed with a correct consttant volume.
Therefore, to correct the volume and Concentration, the control volume stream QH is corrected in accordance with a production continuity equation which had previously been prepared. This control is carried out using the apparatus Shawn in Fig. la. For this purpose the change in the desired value of the Control volume streams must be calculated from new concentration C~
and must then fed to the controllers effective for bringing this about at 28, 3a, and 36. Various types of flow controllers for dQlivery of pulp suspension at the oorrsct concentration may be used, as is known to one Skilled in the art.
Transverse flows of the suspension can take place within the headbox and in the headbox ~tpray nosile. These could result, for ext~mple, due to rage influences in the headbox. Thins can lead to an undeetired affect on the orientation of the fibers in the suspension. In known headboxes, this occurss because of the presence of different volumetric streams over the Gross machine width of the headbox.
Due to the flow control, apparatus of gig, la, the concentration of fibers in the suspension C~ remains constant. The calculated required volumetric stream of QH is fed as a desired value to tho controllers. This adjusts the two streams until the desired volume QM and concentration CM are present in the ~ctream 22.
in accordance with the alternate Control apparatus shown in Fig, 1b, the tame types of oparations~ take place and similar element~t are present, except that both of the streams Qx and QL ar~
controlled by the adjustable valves 32 and 36 which correspond in function to the valve 28. The other element~c in Fig. 1b which correspond to thoste in Fig.
la are similarly numbered. In the apparatus of Fig.
1b, two calculated volumetric streams QH and QL must be _ 1~ _ fAd ast new desired values to the controllers, In Fig.
la, in Contrast, it is possible to operate on a single stream QH to obtain the desirsd value.
The present invention may be applied to various types of headboxes, including single layer headbox, multiple layer headboxes, headboxe;s for slit formats, paper wires, with and without vibration dampers, having one or two tube bundles, etc.
Various headbox and mixer embodiments are shown in pigs. 2-11 and are now briefly described.
Figrs. 2a and 2b illustrate a headbox having individual mixed suspension streams 22 at QM CM
delivered to the headbox. In Fig. 2a, the headbox has an entrance section S2 from the mixer (not shown here), 1b individual section channels 54 in a vArtical stack, which are defined by partitions between them, and a tapering outlet noazle 56 leading to the outlet slot 56 from which the stream 6~, Still at total volumA QM and concentration CM, is sprayed into an inlet nip, onto a wire former, etc., in the usual manner for headboxes.
gig. 2b shows that there are individual streams QM, CM across the width of the machine. Each stream may be supplied by a separate control arrangement ass in hig, la or Fig, 1b. The headbox entrance section is divided into individual aeation~
52a, 82b, e~tc., across the width of the machine. Each of the entrnnce sections is an inlet which feeds a respective plurality of individual channels 54, which, ag can be keen from both of Figs. 2a end 2b, arA
arrayed in rows and columns within the headbox. The channels 54 are in partitioned sections 85a, 55b, 55x, etc. in the headbox. There is a single combined outlet ~0450~8 nozzle 56 through which the various flows from the channels 54 mix and then exit tho headbux. It iS
apparent that control over the individual volumes QM
and concentrations of pulp or fiber CM will control the respective flows through the individual partitioned channels of the partitioned sections 55s, 55b, 55x, for providing a desired uniformity of flow volume and aoncentretion across the width.
Figs. 3n, 3b and 3c show a headbox '70 with to a plura~iity of individual partial sections 54 which are aceparated by individual partitions and supplied by a common mixer 20.
As can be sseen in ~'ig. 3b, the mixer 20 itself might not have individual sections, but its partitioned design would permit some mixing of the suspension passing through the mixer before it reaches the individual sections, like sections: 55, of the headbox, tn Zrig. 3c, in contrast, the mixer 74 also has individual sections 768, 76b, etc., each corresponding to and for delivering mixed suspenstion to respective individual sections 55 of the headbox.
Figs. 4a and 4b show an alternate headbox dessign 80 from th8t shown in Fig9. 2 and 3, wherein there is a unitary and not individually sectioned a5 entrance portion B1 to the hse~dbox, followed by individual separated channels or tubes 82 through the headbox which are arrayed in vertically spaced apart stacl~e end horizontal7.y spaced apart columns. This providea~ individual sections across both the height and the width of the headbox. Each section across the width of the headbox is supplied generally from its own respective adjusted suspension stream ~~, CM. There is 4_ an outlet no:zie 83 from the hGadbox where the various flows through the channels 87 nre recombined.
l~ig. 4c differs from Fiq. 4b only in that the mntry suction $4 of the headbox 86 itself has individual vertical partitions dividing the entry section 84 into individual sections 88a, 88b, etc., corresponding to one or more of the individual channels 82. Some of the chambers 88 may supply more than one of the individual channels 82, as suggested in Fig. 4c.
Figs. 5a and Sb show an alternate headbox 90 Which has an entry chamber area 92 with panels 94 that separate the entry chamber into separate sections 92a~, 92b, etc. Downstream of the sections 92a are narrowed channels 96, which in turn lead into a common 1b transmitting chamber 98 and that leads to the individual section channels 102 which correspond in function and placement to the channels shown in F19.
4a. Following the channels 102 downstream is the outlet nozzle 104. The individual channels 96 are more frequent than the downstream channels 102.
Figs. 6a, 6b and 6c illustrate a headbox 110 and a mixer 112 which cooperate. The headbox includes a plurality of individual arose machine sections i13, as in previous embodiments. each section 2S hays at least one column and more likely n plurality of verbfcally arrayed columns of tubes or channels 114.
~n outlet nossie 116 follows all of the channels 114 downstream. The mixer 112 is at and delivers suspension streams QM C~ to the inlet ends of the passages llQr in the headbox.
Figs. 6a and bb show inlet through the first inlet passage lib of only part of the total flow to the mixer from a control apparatus as in Fig. la or 1b. A separate stream is delivered to the mixer through the pa~asageway 7.20 from a conventional ~tource 122. Therefore the mixer 112 mines the concentration adjusted and volume adjusted stream QM CM and the conventionnl additional stream. Fig. 6c s~howa the mixer 112 as not having partitions dividing it in the cross machine direction. But the mixer 112 could additionally be supplied with partitions like the mixer 74 in F'ig. 3c.
Fig. 7 shows the feeding of the adjusted quantity and concentration mixture ~M, ~ into the mixer 130 through the inlet port 131. ,rust its in the embodiment of rigs. 6a, 6b and 6c, the partial stream QM, CM is only part of the liquid supplied to the hesdbox. A conventional uncontrolled stream of pulp suspension or liquid is delivered to the mixer 130 from the conventional suspension source 132 thrpugh the passages 133.
Then the mixer delivers the mixed su~tpension to the headbox 134 which has ateparated upper and lower tube bundles or channels 135, 136 which in turn deliver a~u~xpension streams to bs mixed in the nozzle 138. The feeding of the mixed partial stream 2S QM, CM its into a channel between the tube bundlest 135, 136, and the tube bundles may, for example, ba defined by oppropriate perforated plates.
Digs. 8a and 8b show another mixer and headbox arrangement. The bandbox 140 has the separate section inlet part 142 which receives only a first liquid stream, e.g., a first controlled adjusted stream or a conventional pulp suspension stream. This is -ls-supplied across the width and height of the headbox by the di~ntributar 143. Downstream of the inlet part 142 is a common entrance section 144 into and across the top of which all of the individually adjusted volume and concentration flows Q~, CM from apparatus as in ~Fi9r, la or lb are introduced through respectiwa ports lab arrayed across the machine width. The section ld4 is followed by the individual channels or tubes, which define the headbox sections 152. That is followed by the noZxie 154, asp in the other embodiments.
Figg. 9a and 9b show an alternate arrangement with a headbox 160 having individual channels or tube bundles 162, 164 above one another.
l~n entry mixer device 166 delivers pulp suspension from a conventional source 168 through passages 169. The controlled volume and concentration flow QM, CM is directly fed into the section channels or tubes 164 without also being fed into the channels or tubes 162, while the conventional flow is !ad into the tubes 162, 2Q but not into the tubes 164. The two flows are therefore separated in their passage through the individual sections of the headbox, but the flows are joined in the nozzle 167 and they exit mixed together through that nozzle outlet 170. From Fig. 9b, it can be seen that the common conventional source 168 feeds liquid not in a common flow but rather in long individual separated tubes 169 across the width of and through the intermediate section 174 and into the top part of the mixer 166 before that liquid is delivered distributed across the headbox to the tubes 162.
Fig. l0a shows an alternate headbox design 180 with a supply of suspension by a conventional supply 182 at its entrance through the tube section 184 and into the common entry area 186. The liquid suspension at controlled volume and concentration gM ~ t is~ fad through the tubes or channels 188 into the no:gle 192. The Conventional liquid leaves the intermediate chamber 186 and passes through the tubes 19~. The separated flow through the tubes 188 and 194 is mixed together in the nozzle 192, like in the embodiment of Figs. 9a and 9b.
Finally, Figs, lla and llb show a headbax 200 having a separated flow, in individual sections in tht form of 202 in the entry section 204 of conventional pulp suspension. The controlled flow QM, cM for the individual sections is delivered through the entrance candufts 206 arrayed across the machine width is the outlet and mixing nozzle 208, which !g downstream from the individual sections 202 through which the conventional suspension travels. The distribution of the individual entrance ports 206 across the width provides the individual sections of the headbox with needed concentration adju~3tment.
In all cases, the flow which has been adjusted across the width of the headbox is reconstituted as a single, corrected concentration and orientation fiber flow in the downstream nozzle before it exits through the discharge outlet.
With respect to some of the above described embodiments, two controlled streams are used. tn others, there is a mixed partial flaw from a conventional source and from the controlled flow QM, CM, which are fed through the headbox entrance section.
The entrance section is developed so that the two ~le-streams mix. In that case, the mixer could bo located directly within the headbox.
Although the present invention has been described in relation to particular embodiments thereof, many other vt~riations and modifications and other uses will become apparent to those skilled in the art: It is preferred, therefore, that the present invention be limited not by the spQCific diselosture heroin, but only by the appended Claims.
WITH MORE UNIFORM FLOW
The present invention relates to a headbox or breaatbox for a papermaking machine, and particular-ly to means for adjusting the pulp density of the pulp xuspen~ion over the working width of the headbOx or the machine width.
One such hsedbox is known from Federal Republic of Germany patent 35 14 554. Such a headbox is fntended to make the pulp ~3uspenr3ion uniform over the entire cross machine width of the pulp outlet from the headbox. At the downstream end of the flow path of the suspension, it should be made uniform in front of the discharge or outlet slot from the headbox. The uniformity sought is such that both the denstity of the pulp. that is the weight of fiber content per unit volume, and the oriunta~tion of the fibers in the pulp ere constant over the width of the pulp outlet from the headbox. Both of these qualities are important prerequisites for the finished paper being produced by the paperma~king machine, in order to have a proper weight per unit area and a proper thicknea;~ profile over the entire cross machine width of the web and so that the paper lies flat and does not tend to curl.
2o~~oaa _Z_ During operation of the pspermaking machine, numerous disturbing factors interfere with the satisfaction of the two uniformity requirements. Thence factors include temperature variations, pressure variations and manufacturing tolerances in the headbox and in the pulp suspension, for example.
The above notad German patent is concerned with s~olvinq tha same problems as are noted above, which are also the problems to be solved by the present invention, That patent recognizes that it is important to both maintain the density of the fibers in the pulp suspension over the width of the pulp outlet and also to control the fiber orientation so that, if it is possible, no transverse !low will occur iri the outlet channel. The oerman patsnt proposes that the density of the pulp suspension be changed locally, that is that the density of the pulp suspension be changed at given places across the machine width, as required. However, the patent does not provide what is believed by the present inventors to be the best solution to this problem.
It is also known to vary the width of the distcharge slot, that is the height of the outlet open~.ng at the disGhar9e slot. One way to do that is by tha use of threaded spindles for swingi»fl or bending one lip, and partfcularly the upper lip that defines the discharge slot. For instance, see Federal Republic ~f Germany patent 29 42 9s6 , corresponding to U.B.
Patent x,326,916, or Federal Republic of Germany publi$hed Application OS 35 35 849. This adjustment of the w$dth of the discharge slot enables local variation of the throughput of the suspension, 11t the same time, however, the direction of suspension flow is also lOCally affected, which affects the orientation of the fibers in the suspension. The local narrowing of the outlet slot causes a different flow direction in the fibers at the narrowed places of the slot than along the remainder of the diaeharge slot. Although the density of the pulp can be made uniform over the width of the pulp outlet by the so-called displacement control, the fibQr orientation, which may have been la good, is undesirably again disturbed. Although the inventors have recognized that the last two above noted Germnn patent applications proceed fundamentally in the correct direction, nonetheless, they do not appear to be able to independently control the two parameters of 15 the density of the pulp and the fiber orientation.
it is an object of the invention to provide a headbox or breastbox which enables independent control of each of the parameters of the den$ity of the ~0 pulp suspension and the fiber orientation in the pulp suspension in a practical and reliable manner.
The concept of the invention involves sectionalizing the headbox into individual sections across the machine width, which is an already known 25 design, and also to feed individually controllable, partial streams or section streams of the pulp suspension to the individual sections of the headbox.
The operating parameters of each individual one of the parbiel streams, particularly their throughput, pulp 30 density and fiber quality, can be individually adjusted without adjusting any of the parameters of the other partial streams or along with adjusting those parameters in the other partial streams differently.
Each of the section streams feeds a respective separate section of the headbox. Each of the section streams is preferably conducted separately through the headbox, and the streams are combined with each other only toward the outlet nozzle from the headbox.
Each section stream is formed by bringing together two separate streams for that section, of which at least one stream in some embodiments, and in other embodiments both streams have their above noted parameters Controlled. Depending upon the mixture ratio and pulp concentration and the flow rate of these control streams, the nature of each of the section streams in each individual section can be very preaidely established.
The headbox of the present invention distributes pulp xuspension over the working width of the papermaking machine and ejects the suspension into the inlet slot or nap of a web forming section, for expmgle.
The headbox includes a pulp suspension guide device through which peas a plurality of holes or channels that define the channels and that extend from the upstream to the downstream sides of the headbax.
The holes or channels are in a Selected array across the width of the headbox. There is a discharge nozzle also extending across the width of the machine with a discharge or outlet slot for distributing the pulp suspension.
Upstream of the headbox in the pulp suspension flow path are located means far adjusting the pulp density of the pulp suspension over the working width of the machine. The individual BeCtions of the haadbox are formed by partitions which divide the headbox into individual separate sections over the cro** machine width. Each individual section has at least one feed line channel or hole for feeding through !t a partial r~tream or section stream of the pulp su*pen*ion.
A mixer is arxanged upstream of or in front of the feed line of the headbox. In one embodiment, the mixer has at least two connections for introducing respective parameter controlled suspension streams, having predetermined operating parameters, such as throughput, pulp density and fiber quality. In other embodiments, fewer than or only one of the connections and its suspension stream i$ controlled. But through merely that control, the final mixed output from the discharge slot is controlled.
Other objects and features of the present invention will become apparent form the following de*cription of preferred embodiments of the invention considered in connection with the accompanying drawinq~~ in which:
gig, is schematically illustrates one pulp sua~psnsion flow mixing apparatus, and shows means for mixing flows that are supplied to individual sections o~ the headbox;
his. 1b illustrates an alternate pulp suspension flow mixting apparatu9;
-s-Fig. 2a is a aide elevationai cross-sectional view through one individual section of 8 B rat embodiment of a headbox, with a plurality of individual pulp flow channels through it;
gig. ~b fs a plan cross-Sectional view of the headbox of Fig. 2s showing individual, headbox sections and showing a plurality of channels through the haadbox arrayed across the width of the machine and in each of the individual headbox sections~f P'ig. 3a illustrates a second headbox embodiment Like that in Fig. 2a and 2b and schematically depicts the mixer which delivers parameter controlled suspension to the headbox;
~'ig. 3b is an end view of the mixer of Fiq. 3a, seen in the direction of arrow A in Fig. 3a, showing individual deliveries of mixed suspension to tht mixer for subseciuent delivery to the headbox;
Fig. 3c is a view in the same direction as l~fg. 3b, showing a partitioned mixer embodiment for individual deliveries of mixed suspension to the headbox;
F'ig. 4a is a side elevational cross-sectionol view through a third embodiment of ~ headbox, where the individual sections are narrowed channels a5 through the headbox and there arQ a plurality of thosQ
channels in each section, which are arrayed vertically acroga the headbox;
Fig. 4b is a plan cross-sectional partial view of the headbox of Fig. 4a showing the partitioned headbox, showing the deliveries of different mixtures of pulp suspension to the headbox and Showing the individual channel sections arrayed across the machine width Fig. ~c is an alternate fourth embodiment Of the headbox and mixer of Fig. 4b, wherein the mixer has individual partitioned sections, each for transmitting to the headbox a respective mixture of pulp suspension;
gig. Sa is a side elevational crosa-seationnl view of a fifth embodiment of a haadbox and mixer, showing two longitudinally spaced areas of partial channel sactions~ in the headbox;
i~ig. Sb is a plan cross-sectional view of the headbox of Fig. 3a, showing the individual sections of the mixer across the width of the headbox;
Fig. 6a is a aide elevational cro~s-sectional view of a sixth embodiment of a headbox and mixer combination, wherein the mixer ist fed with a premixed partial stream which is mixed with a conventional supply of pulp suspen$ion;
Fig. 6b is an enlarged detail of P~iq. Gas ~'iQ. 6c is a rear view of the mixer of Fig.
6a, showing the suspension or material feed to the mixer;
Fig. 7 i~c a side elevational cross-sectionai view of a seventh embodiment of a headbox and mixer combination where the mixed partial sttreams are ~5 fad into a channel between the tube bundles through the haadbox;
his. 8a is a top view of an eighth embodiment of a mixer and headbox combination wherein the piuraiity of parameter controlled partial streams are fed to connections acrossc the top of the headbox past the introduction mixer;
Fig. 8b i$ a top view of the headboa and mixfr combination of Fig, 8a;
Fig. 9a is a side olevdtiona~l cross-goctional view of a ninth embodiment of a combination of headbox and mixer showing direct feeding of the conneadtions across controlled partial stream into one or more of the tube lines of the turbulence inserts of a suction of the headbox=
f'ig. 9b is rear view of the headbox of Fig.
1.0 9a in the direction of arrow C in Fig. 9a;
Fig, 10a is a side elevational cross-sectional view of an alternate, tenth embodiment of a headbox with direct feed of a controlled mixture partial stream into one or more of the tube lines;
Ffg, lOb i$ a plon longitudinal cross section of the headbox and mixer of Fib, l0af Fig, ila is a side elevational cross-seationai, fragmentary, view of an eleventh embodiment of a headbox showing feeding of the parameter controlled mixtuxe into the nozzle space downstream of the individual sections; and Fig. lib is a top view of the headbox of Fig. ila, In the pulp su~xpens~ion control apparatus shown in ~'ig, la, the mixer 20 delivers to the headbox, not shown in xig. la, a mixed stream 22 having the volume ~ and having the concentration CM of fiber material in the pulp suspension.
3~ Th8 mixer 20 is supplied by two separate pulp suspension streams which are brought together in 2fl45038 9 _ tha mixer. The first stream 2~ has the volume Qx and the fiber concentration CH. The second stream 26 has the volume QL and the fiber concentration CL.
The first pulp stream 24 is supplied from a ~tource, not shown, past the volumetric control, adjustable valve 28 that is controlled by flow rate controller 32. The second pulp str:am 26 is supplied from another source, dnd it is mixed with a separate pulp supply at the volumetric control, adjustable valve 1.0 34. The valve 3a is controlled by the flow rate controller 36. That controller, in turn, is supplied by the two liquid or suspension streams from the scparote pulp sources 38 and 42 which are mixed in the mixer at the controller 36. Adjustment of the valves 28 and 34 determines the volume ratios QH/QL. Also, by appropriate control over special pulp sources 38 and 42, it is possible to adjust the concentration CL of pulp suspension in pulp stream 26, therQby to adjust the !low rate and the fiber concentration in conduit 22.
An actual situation controlled by the control apparatus of Fig. la is now described. The arrangement shown in Fig, la just delivers a pulp su~tpansior, flow to a conduit 22 which i;~ connected to 2S ona of the individual sections of a headbox. As will be apparent below, there may be an individual one of the control apparatus shown in Fig. la for each of the individual sections of the headbox across the machine width, and each of those individual control apparatus shown fn P'ig, la can be operated independently.
wring a periodic quality control check of the paper web being produced or of the pulp $uspen$ion -lo-being dispensed by the headbox, it may be found that the weight per unit area profile, at the individual section across the width of the web, of the mixed pulp suspension which is supplied through mixer 20 in Fig.
S la and controlled by the control devices shown in Fig.
la, differs beyond an acceptable level from a desirQd value, either in flow volume QM or pulp ~euspansion aoncentrntion CM. Therefore, the pulp density of the suspension in the headbox must be suitably corrected at this section across the width of the headbox.
According to the invention, the adjustment can be made by varyfng the concentration CM of the individual section stream 22 that is controlled by the control apparatus shown in Fig. 1A. The necessary change in CM, that is dCji, can be determined from a previously prepared weight balance sheet. The resulting corrected concentration C~ is dependent exclusively upon the ratio of the control streamss QH/QL. The fiowthrough of theca two streams may be halted while the ratio adjustment is made. The corrected value of CM is used as a basis far ratio control to establish the dasir~ad value setting. The ratio control eats the new controi/flow ratio Q~/CM, in Fig. 1A this is accomplished by changing QL, e.g.
through valve 34 and through sources 3a and ~2.
~towevar, it ia~ important that the combined volumetric flow Q~ remain constant, so that the individual headbox section may be fed with a correct consttant volume.
Therefore, to correct the volume and Concentration, the control volume stream QH is corrected in accordance with a production continuity equation which had previously been prepared. This control is carried out using the apparatus Shawn in Fig. la. For this purpose the change in the desired value of the Control volume streams must be calculated from new concentration C~
and must then fed to the controllers effective for bringing this about at 28, 3a, and 36. Various types of flow controllers for dQlivery of pulp suspension at the oorrsct concentration may be used, as is known to one Skilled in the art.
Transverse flows of the suspension can take place within the headbox and in the headbox ~tpray nosile. These could result, for ext~mple, due to rage influences in the headbox. Thins can lead to an undeetired affect on the orientation of the fibers in the suspension. In known headboxes, this occurss because of the presence of different volumetric streams over the Gross machine width of the headbox.
Due to the flow control, apparatus of gig, la, the concentration of fibers in the suspension C~ remains constant. The calculated required volumetric stream of QH is fed as a desired value to tho controllers. This adjusts the two streams until the desired volume QM and concentration CM are present in the ~ctream 22.
in accordance with the alternate Control apparatus shown in Fig, 1b, the tame types of oparations~ take place and similar element~t are present, except that both of the streams Qx and QL ar~
controlled by the adjustable valves 32 and 36 which correspond in function to the valve 28. The other element~c in Fig. 1b which correspond to thoste in Fig.
la are similarly numbered. In the apparatus of Fig.
1b, two calculated volumetric streams QH and QL must be _ 1~ _ fAd ast new desired values to the controllers, In Fig.
la, in Contrast, it is possible to operate on a single stream QH to obtain the desirsd value.
The present invention may be applied to various types of headboxes, including single layer headbox, multiple layer headboxes, headboxe;s for slit formats, paper wires, with and without vibration dampers, having one or two tube bundles, etc.
Various headbox and mixer embodiments are shown in pigs. 2-11 and are now briefly described.
Figrs. 2a and 2b illustrate a headbox having individual mixed suspension streams 22 at QM CM
delivered to the headbox. In Fig. 2a, the headbox has an entrance section S2 from the mixer (not shown here), 1b individual section channels 54 in a vArtical stack, which are defined by partitions between them, and a tapering outlet noazle 56 leading to the outlet slot 56 from which the stream 6~, Still at total volumA QM and concentration CM, is sprayed into an inlet nip, onto a wire former, etc., in the usual manner for headboxes.
gig. 2b shows that there are individual streams QM, CM across the width of the machine. Each stream may be supplied by a separate control arrangement ass in hig, la or Fig, 1b. The headbox entrance section is divided into individual aeation~
52a, 82b, e~tc., across the width of the machine. Each of the entrnnce sections is an inlet which feeds a respective plurality of individual channels 54, which, ag can be keen from both of Figs. 2a end 2b, arA
arrayed in rows and columns within the headbox. The channels 54 are in partitioned sections 85a, 55b, 55x, etc. in the headbox. There is a single combined outlet ~0450~8 nozzle 56 through which the various flows from the channels 54 mix and then exit tho headbux. It iS
apparent that control over the individual volumes QM
and concentrations of pulp or fiber CM will control the respective flows through the individual partitioned channels of the partitioned sections 55s, 55b, 55x, for providing a desired uniformity of flow volume and aoncentretion across the width.
Figs. 3n, 3b and 3c show a headbox '70 with to a plura~iity of individual partial sections 54 which are aceparated by individual partitions and supplied by a common mixer 20.
As can be sseen in ~'ig. 3b, the mixer 20 itself might not have individual sections, but its partitioned design would permit some mixing of the suspension passing through the mixer before it reaches the individual sections, like sections: 55, of the headbox, tn Zrig. 3c, in contrast, the mixer 74 also has individual sections 768, 76b, etc., each corresponding to and for delivering mixed suspenstion to respective individual sections 55 of the headbox.
Figs. 4a and 4b show an alternate headbox dessign 80 from th8t shown in Fig9. 2 and 3, wherein there is a unitary and not individually sectioned a5 entrance portion B1 to the hse~dbox, followed by individual separated channels or tubes 82 through the headbox which are arrayed in vertically spaced apart stacl~e end horizontal7.y spaced apart columns. This providea~ individual sections across both the height and the width of the headbox. Each section across the width of the headbox is supplied generally from its own respective adjusted suspension stream ~~, CM. There is 4_ an outlet no:zie 83 from the hGadbox where the various flows through the channels 87 nre recombined.
l~ig. 4c differs from Fiq. 4b only in that the mntry suction $4 of the headbox 86 itself has individual vertical partitions dividing the entry section 84 into individual sections 88a, 88b, etc., corresponding to one or more of the individual channels 82. Some of the chambers 88 may supply more than one of the individual channels 82, as suggested in Fig. 4c.
Figs. 5a and Sb show an alternate headbox 90 Which has an entry chamber area 92 with panels 94 that separate the entry chamber into separate sections 92a~, 92b, etc. Downstream of the sections 92a are narrowed channels 96, which in turn lead into a common 1b transmitting chamber 98 and that leads to the individual section channels 102 which correspond in function and placement to the channels shown in F19.
4a. Following the channels 102 downstream is the outlet nozzle 104. The individual channels 96 are more frequent than the downstream channels 102.
Figs. 6a, 6b and 6c illustrate a headbox 110 and a mixer 112 which cooperate. The headbox includes a plurality of individual arose machine sections i13, as in previous embodiments. each section 2S hays at least one column and more likely n plurality of verbfcally arrayed columns of tubes or channels 114.
~n outlet nossie 116 follows all of the channels 114 downstream. The mixer 112 is at and delivers suspension streams QM C~ to the inlet ends of the passages llQr in the headbox.
Figs. 6a and bb show inlet through the first inlet passage lib of only part of the total flow to the mixer from a control apparatus as in Fig. la or 1b. A separate stream is delivered to the mixer through the pa~asageway 7.20 from a conventional ~tource 122. Therefore the mixer 112 mines the concentration adjusted and volume adjusted stream QM CM and the conventionnl additional stream. Fig. 6c s~howa the mixer 112 as not having partitions dividing it in the cross machine direction. But the mixer 112 could additionally be supplied with partitions like the mixer 74 in F'ig. 3c.
Fig. 7 shows the feeding of the adjusted quantity and concentration mixture ~M, ~ into the mixer 130 through the inlet port 131. ,rust its in the embodiment of rigs. 6a, 6b and 6c, the partial stream QM, CM is only part of the liquid supplied to the hesdbox. A conventional uncontrolled stream of pulp suspension or liquid is delivered to the mixer 130 from the conventional suspension source 132 thrpugh the passages 133.
Then the mixer delivers the mixed su~tpension to the headbox 134 which has ateparated upper and lower tube bundles or channels 135, 136 which in turn deliver a~u~xpension streams to bs mixed in the nozzle 138. The feeding of the mixed partial stream 2S QM, CM its into a channel between the tube bundlest 135, 136, and the tube bundles may, for example, ba defined by oppropriate perforated plates.
Digs. 8a and 8b show another mixer and headbox arrangement. The bandbox 140 has the separate section inlet part 142 which receives only a first liquid stream, e.g., a first controlled adjusted stream or a conventional pulp suspension stream. This is -ls-supplied across the width and height of the headbox by the di~ntributar 143. Downstream of the inlet part 142 is a common entrance section 144 into and across the top of which all of the individually adjusted volume and concentration flows Q~, CM from apparatus as in ~Fi9r, la or lb are introduced through respectiwa ports lab arrayed across the machine width. The section ld4 is followed by the individual channels or tubes, which define the headbox sections 152. That is followed by the noZxie 154, asp in the other embodiments.
Figg. 9a and 9b show an alternate arrangement with a headbox 160 having individual channels or tube bundles 162, 164 above one another.
l~n entry mixer device 166 delivers pulp suspension from a conventional source 168 through passages 169. The controlled volume and concentration flow QM, CM is directly fed into the section channels or tubes 164 without also being fed into the channels or tubes 162, while the conventional flow is !ad into the tubes 162, 2Q but not into the tubes 164. The two flows are therefore separated in their passage through the individual sections of the headbox, but the flows are joined in the nozzle 167 and they exit mixed together through that nozzle outlet 170. From Fig. 9b, it can be seen that the common conventional source 168 feeds liquid not in a common flow but rather in long individual separated tubes 169 across the width of and through the intermediate section 174 and into the top part of the mixer 166 before that liquid is delivered distributed across the headbox to the tubes 162.
Fig. l0a shows an alternate headbox design 180 with a supply of suspension by a conventional supply 182 at its entrance through the tube section 184 and into the common entry area 186. The liquid suspension at controlled volume and concentration gM ~ t is~ fad through the tubes or channels 188 into the no:gle 192. The Conventional liquid leaves the intermediate chamber 186 and passes through the tubes 19~. The separated flow through the tubes 188 and 194 is mixed together in the nozzle 192, like in the embodiment of Figs. 9a and 9b.
Finally, Figs, lla and llb show a headbax 200 having a separated flow, in individual sections in tht form of 202 in the entry section 204 of conventional pulp suspension. The controlled flow QM, cM for the individual sections is delivered through the entrance candufts 206 arrayed across the machine width is the outlet and mixing nozzle 208, which !g downstream from the individual sections 202 through which the conventional suspension travels. The distribution of the individual entrance ports 206 across the width provides the individual sections of the headbox with needed concentration adju~3tment.
In all cases, the flow which has been adjusted across the width of the headbox is reconstituted as a single, corrected concentration and orientation fiber flow in the downstream nozzle before it exits through the discharge outlet.
With respect to some of the above described embodiments, two controlled streams are used. tn others, there is a mixed partial flaw from a conventional source and from the controlled flow QM, CM, which are fed through the headbox entrance section.
The entrance section is developed so that the two ~le-streams mix. In that case, the mixer could bo located directly within the headbox.
Although the present invention has been described in relation to particular embodiments thereof, many other vt~riations and modifications and other uses will become apparent to those skilled in the art: It is preferred, therefore, that the present invention be limited not by the spQCific diselosture heroin, but only by the appended Claims.
Claims (80)
1. A headbox for a papermaking machine for distributing pulp suspension over the working width of the papermaking machine, comprising:
(a) a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
(b) a discharge nozzle including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, the discharge nozzle being shaped such that the direction of flow of the pulp suspension between the downstream side of the pulp suspension guide and the discharge outlet as viewed from a side of the headbox remains essentially unchanged until down to the discharge outlet thereby to prevent mixing of the pulp suspension from the respective channels of the pulp suspension guide;
(c) means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
flow means upstream of the pulp suspension guide having partitions dividing the flow means into a plurality of sections extending in the direction of flow of the pulp suspension and arranged side by side over the width of the papermaking machine, each section having at least two connections for the introduction of respective streams (QH, QL), at least one stream (QH, QL) of each section having a pulp concentration; at least one of the connections of each section including means for providing at least one of the respective streams (QH, QL) of that section with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of that section, in each section of the flow means the streams (QH, QL) are mixed to form a respective sectional mixed stream (QM) with a concentration (CM) which depends on the ratio of the volumetric flows of the streams (QH, QL), and each section of the flow means feeding at least one of the channels of the pulp suspension guide with the respective sectional mixed stream (QM), and means maintaining the sectional mixed stream (QM) of pulp suspension of each section at a volumetric flow that is a constant for the respective section of the flow means during the adjustment of the ratio of the volumetric flows of the streams (QH, QL), for maintaining a desired fiber orientation cross profile in the paper web produced.
(a) a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
(b) a discharge nozzle including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, the discharge nozzle being shaped such that the direction of flow of the pulp suspension between the downstream side of the pulp suspension guide and the discharge outlet as viewed from a side of the headbox remains essentially unchanged until down to the discharge outlet thereby to prevent mixing of the pulp suspension from the respective channels of the pulp suspension guide;
(c) means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
flow means upstream of the pulp suspension guide having partitions dividing the flow means into a plurality of sections extending in the direction of flow of the pulp suspension and arranged side by side over the width of the papermaking machine, each section having at least two connections for the introduction of respective streams (QH, QL), at least one stream (QH, QL) of each section having a pulp concentration; at least one of the connections of each section including means for providing at least one of the respective streams (QH, QL) of that section with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of that section, in each section of the flow means the streams (QH, QL) are mixed to form a respective sectional mixed stream (QM) with a concentration (CM) which depends on the ratio of the volumetric flows of the streams (QH, QL), and each section of the flow means feeding at least one of the channels of the pulp suspension guide with the respective sectional mixed stream (QM), and means maintaining the sectional mixed stream (QM) of pulp suspension of each section at a volumetric flow that is a constant for the respective section of the flow means during the adjustment of the ratio of the volumetric flows of the streams (QH, QL), for maintaining a desired fiber orientation cross profile in the paper web produced.
2. The headbox of claim 1, wherein each of the streams (QH, QL) has a pulp concentration.
3. The headbox of claim 2, wherein the pulp concentration of at least one of the streams (QH, QL) is different than the other.
4. The headbox of claim 1, wherein each section of the flow means comprises a mixer and a pulp guide section downstream of the mixer and upstream of the pulp suspension guide.
5. The headbox of claim 4, further comprising a respective mixer connection for each of the individual flow means sections, for individually setting the operating parameters for each of the sections.
6. The headbox of claim 5, further comprising suspension parameter control means connected to the mixer connection, and including means for adjusting the parameters.
7. The headbox of claim 6, wherein the parameter control means for the respective connection further comprises means for adjusting the concentration of fiber in the pulp suspension passing through the respective connection.
8. The headbox of claim 6, wherein there is a respective suspension parameter control means connected with each of the two connections.
9. The headbox of claim 5, wherein the mixer also is divided by partitions into individual mixer sections over the width of the machine, and each of the individual mixer sections comprises means for delivering suspension to respective ones of the flow means sections.
10. The headbox of claim 5, wherein there are a plurality of the connections between the flow means sections and the mixer at spaced apart locations across the machine width, and the mixer is undivided across the machine width, and the undivided mixer communicates with the channels of the pulp suspension guide through the flow means, such that the distribution of the connections to the mixer across the mixer delivers individually controlled suspension streams to the individual channels of the guide.
11. The headbox of claim 4, wherein the pulp guide section is partitioned into sections across the width of the headbox.
12. The headbox of claim 11, wherein the pulp suspension guide sections are formed by one of a perforated plate, a plurality of tubes, horizontal or vertical plates or flexible blades.
13. The headbox of claim 4, wherein connections between each mixer and the pulp guide section comprise hoses or pipes.
14. The headbox of claim 4, wherein connections between each mixer and the pulp guide section comprises an additional chamber partitioned into sections.
15. The headbox of claim 14, wherein at least one of the mixer and the additional chamber sections have varying widths.
16. The headbox of claim 11, wherein the sections of the pulp guide section have varying widths.
17. The headbox of claim 1, wherein the flow means comprises a plurality of mixers, the mixers arranged upstream of the sections of the flow means, each mixer feeding pulp suspension to one section.
18. The headbox of claim 1, wherein the flow means comprises at least one mixer, said mixer arranged upstream of the sections of the flow means and feeding pulp suspension to a plurality of said sections.
19. The headbox of claim 1, wherein the flow means comprises a plurality of mixers arranged upstream of the sections of the flow means and said plurality of mixers feeding pulp suspension to one section.
20. A headbox for a papermaking machine for distributing pulp suspension over the working width of the papermaking machine, comprising:
(a) a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
(b) a discharge nozzle including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, the headbox being structured and arranged so that the direction of flow of the pulp suspension between the downstream side of the pulp suspension guide and the discharge outlet as viewed from a side of the headbox remains essentially unchanged until down to the discharge outlet thereby to prevent mixing of the pulp suspension from the respective channels of the pulp suspension guide;
(c) means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
a plurality of flow elements arranged upstream of the pulp suspension guide, each flow element provided with at least two connections for the introduction of respective streams (QH, QL) into the flow element to form a mixed stream (QM) with a concentration CM in the flow element which concentration depends on the ratio of the volumetric flows of the streams (QH, QL), at least one (QH, QL) of each flow element stream having a pulp concentration, at least one of the connections of each flow element including means for providing a respective stream (QH, QL) with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of each flow element, each flow element feeding at least one of the channels of the pulp suspension guide with the respective mixed stream (QM), each flow element further comprising an outlet for discharging of the respective mixed stream into the pulp suspension guide;
and means maintaining the mixed stream (QM) of pulp suspension of each flow element at a volumetric flow that is a constant for each flow element during the adjustment of the ratio of the volumetric flows of the streams (QH, QL) for maintaining a desired fiber orientation cross profile in the paper web produced.
(a) a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
(b) a discharge nozzle including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, the headbox being structured and arranged so that the direction of flow of the pulp suspension between the downstream side of the pulp suspension guide and the discharge outlet as viewed from a side of the headbox remains essentially unchanged until down to the discharge outlet thereby to prevent mixing of the pulp suspension from the respective channels of the pulp suspension guide;
(c) means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
a plurality of flow elements arranged upstream of the pulp suspension guide, each flow element provided with at least two connections for the introduction of respective streams (QH, QL) into the flow element to form a mixed stream (QM) with a concentration CM in the flow element which concentration depends on the ratio of the volumetric flows of the streams (QH, QL), at least one (QH, QL) of each flow element stream having a pulp concentration, at least one of the connections of each flow element including means for providing a respective stream (QH, QL) with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of each flow element, each flow element feeding at least one of the channels of the pulp suspension guide with the respective mixed stream (QM), each flow element further comprising an outlet for discharging of the respective mixed stream into the pulp suspension guide;
and means maintaining the mixed stream (QM) of pulp suspension of each flow element at a volumetric flow that is a constant for each flow element during the adjustment of the ratio of the volumetric flows of the streams (QH, QL) for maintaining a desired fiber orientation cross profile in the paper web produced.
21. The headbox of claim 20, wherein each flow element comprises a mixer and a pulp guide section downstream of the mixer and upstream of the pulp suspension guide.
22. The headbox of claim 20, wherein each of the streams (QH, QL) has a pulp concentration.
23. The headbox of claim 22, wherein the pulp concentration of at least one of the streams (QH, QL) is different than the other.
24. The headbox of claim 21, further comprising a respective mixer connection for each of the individual flow elements for individually setting the operating parameters for each of the elements.
25. The headbox of claim 24, further comprising suspension parameter control means connected to the mixer connection, and including means for adjusting the parameters.
26. The headbox of claim 25, wherein the parameter control means for the respective connection further comprises means for adjusting the concentration of fiber in the pulp suspension passing through the respective connection.
27. The headbox of claim 25, wherein there is a respective suspension parameter control means connected with each of the two connections.
28. The headbox of claim 24, wherein the mixer is divided by partitions into individual mixer sections over the width of the machine, and each of the individual mixer sections comprises means for delivering suspension to respective ones of the flow element.
29. The headbox of claim 24, wherein there are a plurality of the connections between the flow elements and the mixer at spaced apart locations across the machine width, and the mixer is undivided across the machine width, and the undivided mixer communicates with the channels of the pulp suspension guide through the flow elements, such that the distribution of the connections to the mixer across the mixer delivers individually controlled suspension streams to the individual channels of the guide.
30. The headbox of claim 21, wherein the pulp guide section is partitioned into sections across the width of the headbox.
31. The headbox of claim 30, wherein the pulp suspension guide sections are formed by one of a perforated plate, a plurality of tubes, horizontal or vertical plates or flexible blades.
32. The headbox of claim 21, wherein connections between each mixer and the pulp guide section comprise hoses or pipes.
33. The headbox of claim 21, wherein connections between each mixer and the pulp guide section comprises an additional chamber partitioned into sections.
34. The headbox of claim 33, wherein at least one of the mixer and the additional chamber sections have varying widths.
35. The headbox of claim 30, wherein the sections of the pulp guide section have varying widths.
36. The headbox of claim 20, wherein each flow element outlet feeds at least one of the channels of the pulp suspension guide with a mixed stream through a respective connection and wherein the connections between the respective outlets of the flow elements and the channels of the pulp suspension guide comprise tubes, pipes or hoses.
37. The headbox of claim 36, wherein each flow means comprises a mixer and a pulp guide section downstream of the mixer and upstream of the pulp suspension guide.
38. The headbox of claim 20, further comprising at least one of the at least two connections comprising a valve means.
39. The headbox of claim 36, further comprising at least one of the at least two connections comprising a valve means.
40. A headbox for a papermaking machine for distributing pulp suspension over the working width of the papermaking machine, comprising:
a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
a discharge nozzle, including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, the headbox being structured and arranged so that the direction of flow of the pulp suspension between the downstream side of the pulp suspension guide and the discharge outlet as viewed from a side of the headbox remains essentially unchanged until down to the discharge outlet thereby to prevent mixing of the pulp suspension from the respective channels of the pulp suspension guide; and means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
flow means arranged upstream of the pulp suspension guide, the flow means having at least two sections, at least one section provided with at least two connections for the introduction of respective streams (QH, QL), at least one stream (QH, QL) having a pulp concentration, at least one of the connections of the at least one section including means for providing at least one of the respective streams (QH, QL) of the at least one section with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of the at least one section, in the at least one section of the flow means the streams (QH, QL) are mixed to form a mixed stream (QM) with a concentration (CM) which depends on the ratio of the volumetric flows of the streams (QH, QL), and each section of the flow means feeding at least one of the channels of the pulp suspension guide, said at least one section feeding at least one of the channels with the mixed stream (QM), the flow means further comprising an outlet for discharging of the mixed stream into the pulp suspension guide, and means maintaining the mixed stream (QM) of pulp suspension at a volumetric flow that is a constant during the adjustment of the ratio of the volumetric flows of the streams (QH, QL) for maintaining a desired fiber orientation cross profile in the paper web produced.
a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
a discharge nozzle, including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, the headbox being structured and arranged so that the direction of flow of the pulp suspension between the downstream side of the pulp suspension guide and the discharge outlet as viewed from a side of the headbox remains essentially unchanged until down to the discharge outlet thereby to prevent mixing of the pulp suspension from the respective channels of the pulp suspension guide; and means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
flow means arranged upstream of the pulp suspension guide, the flow means having at least two sections, at least one section provided with at least two connections for the introduction of respective streams (QH, QL), at least one stream (QH, QL) having a pulp concentration, at least one of the connections of the at least one section including means for providing at least one of the respective streams (QH, QL) of the at least one section with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of the at least one section, in the at least one section of the flow means the streams (QH, QL) are mixed to form a mixed stream (QM) with a concentration (CM) which depends on the ratio of the volumetric flows of the streams (QH, QL), and each section of the flow means feeding at least one of the channels of the pulp suspension guide, said at least one section feeding at least one of the channels with the mixed stream (QM), the flow means further comprising an outlet for discharging of the mixed stream into the pulp suspension guide, and means maintaining the mixed stream (QM) of pulp suspension at a volumetric flow that is a constant during the adjustment of the ratio of the volumetric flows of the streams (QH, QL) for maintaining a desired fiber orientation cross profile in the paper web produced.
41. The headbox recited in claim 40, wherein said flow means comprises a mixer and a pulp guide section downstream of the mixer and upstream of the pulp suspension guide.
42. The headbox of claim 41, wherein the flow means comprises a plurality of mixers, each having at least two connections for the introduction of respective partial pulp suspension streams, said plurality of mixers feeding respective mixed streams into a common pulp guide section downstream of the mixers and upstream of the pulp suspension guide.
43. The headbox of claim 40, wherein the flow means outlet further comprises an outlet from each section, the outlet from said at least one section being for discharging of the mixed stream from said at least one section, said outlet from the at least one section feeding at least one of the channels of the pulp suspension guide with the mixed stream, respective connections being provided between the outlets and channels of the pulp suspension guide and wherein the connections between the respective outlets of the sections of the flow means and the channels of the pulp suspension guide comprises tubes, pipes or hoses.
44. The headbox of claim 40, wherein each of the streams (QH, QL) has a pulp concentration.
45. The headbox of claim 44, wherein the pulp concentration of at least one of the streams (QH, QL) is different than the other.
46. The headbox of claim 40, wherein the flow means has at least two sections each having at least two connections for the introduction of said streams (QH, QL).
47. The headbox recited in claim 42, wherein said common pulp guide section is divided into a plurality of separate compartments.
48. The headbox recited in claim 47, wherein a mixed stream from each mixer feeds into a respective compartment of the pulp guide common section.
49. The headbox of claim 47, wherein a mixed stream from at least one mixer is fed into a plurality of compartments of said pulp guide common section.
50. The headbox of claim 47, wherein a plurality of mixed streams from a plurality of respective mixers are introduced into a single compartment of said pulp guide common section.
51. The headbox of claim 47, wherein each pulp stream in a compartment of the pulp guide common section is introduced into a respective channel of the pulp suspension guide.
52. The headbox of claim 47, wherein a pulp stream of a compartment of said pulp guide common section is introduced into a plurality of channels of said pulp suspension guide.
53. The headbox of claim 47, wherein a plurality of partial streams from plural ones of said compartments of said pulp guide common section are introduced into a single channel of said pulp suspension guide.
54. The headbox of claim 40, wherein the flow means is partitioned into a plurality of sections and wherein each section of the flow means comprises a mixer and a pulp guide section downstream of the mixer and upstream of the pulp suspension guide.
55. The headbox of claim 54, further comprising a respective mixer connection for each of the individual flow means sections, for individually setting the operating parameters for each of the sections.
56. The headbox of claim 55, further comprising suspension parameter control means connected to the mixer connection, and including means for adjusting the parameters.
57. The headbox of claim 56, Wherein the parameter control means for the respective connection further comprises means for adjusting the concentration of fiber in the pulp suspension passing through the respective connection.
58. The headbox of claim 56, wherein there is a respective suspension parameter control means connected with each of the two connections.
59. The headbox of claim 55, wherein the mixer also is divided by partitions into individual mixer sections over the width of the machine, and each of the individual mixer sections comprises means for delivering suspension to respective ones of the flow means sections.
60. The headbox of claim 55, wherein there are a plurality of the connections between the flow means sections and the mixer at spaced apart locations across the machine width, and the mixer is undivided across the machine width, and the undivided mixer communicates with the channels of the pulp suspension guide through the flow means, such that the distribution of the connections to the mixer across the mixer delivers individually controlled suspension streams to the individual channels of the guide.
61. The headbox of claim 60, wherein the pulp suspension guide sections are formed by one of a perforated plate, a plurality of tubes, horizontal or vertical plates or flexible blades.
62. The headbox of claim 54, wherein connections between each mixer and the pulp guide section comprise hoses or pipes.
63. The headbox of claim 54, wherein connections between each mixer and the pulp guide section comprises an additional chamber partitioned into sections.
64. The headbox of claim 63, wherein at least one of the mixer and the additional chamber sections have varying widths.
65. The headbox of claim 60, wherein the sections of the pulp guide section have varying widths.
66. The headbox of claim 40, wherein the flow means is partitioned into a plurality of sections and wherein the flow means comprises a plurality of mixers, the mixers arranged upstream of the sections of the flow means, each mixer feeding pulp suspension to a section.
67. The headbox of claim 40, wherein the flow means is partitioned into a plurality of sections and wherein the flow means comprises at least one mixer, said mixer arranged upstream of the sections of the flow means and feeding pulp suspension to a plurality of said sections.
68. The headbox of claim 40, wherein the flow means is partitioned into a plurality of sections and wherein the flow means comprises a plurality of mixers arranged upstream of the sections of the flow means and said plurality of mixers feeding pulp suspension to one section.
69. A headbox for a papermaking machine for distributing pulp suspension over the working width of the papermaking machine, comprising:
(a) a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
(b) a discharge nozzle including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, (c) means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
flow means upstream of the pulp suspension guide having partitions dividing the flow means into a plurality of sections extending in the direction of flow of the pulp suspension and arranged side by side over the width of the papermaking machine, each section having at least two connections for the introduction of respective streams (QH, QL), at least one stream (QH, QL) of each section having a pulp concentration; at least one of the connections of each section including means for providing at least one of the respective streams (QH, QL) of that section with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of that section, in each section of the flow means the streams (QH, QL) are mixed to form a respective sectional mixed stream (QM) with a concentration (CM) which depends on the ratio of the volumetric flows of the streams (QH, QL), and each section of the flow means feeding at least one of the channels of the pulp suspension guide with the respective sectional mixed stream (QM), and means maintaining the sectional mixed stream (QM) of pulp suspension of each section at a volumetric flow that is a constant for the respective section of the flow means during adjustment of the ratio of the volumetric flows of the streams (QH, QL) for maintaining a desired fiber orientation cross profile in the paper web produced.
(a) a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
(b) a discharge nozzle including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, (c) means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
flow means upstream of the pulp suspension guide having partitions dividing the flow means into a plurality of sections extending in the direction of flow of the pulp suspension and arranged side by side over the width of the papermaking machine, each section having at least two connections for the introduction of respective streams (QH, QL), at least one stream (QH, QL) of each section having a pulp concentration; at least one of the connections of each section including means for providing at least one of the respective streams (QH, QL) of that section with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of that section, in each section of the flow means the streams (QH, QL) are mixed to form a respective sectional mixed stream (QM) with a concentration (CM) which depends on the ratio of the volumetric flows of the streams (QH, QL), and each section of the flow means feeding at least one of the channels of the pulp suspension guide with the respective sectional mixed stream (QM), and means maintaining the sectional mixed stream (QM) of pulp suspension of each section at a volumetric flow that is a constant for the respective section of the flow means during adjustment of the ratio of the volumetric flows of the streams (QH, QL) for maintaining a desired fiber orientation cross profile in the paper web produced.
70. The headbox of claim 69, wherein each of the streams (QH, QL) has a pulp concentration.
71. The headbox of claim 70, wherein the pulp concentration of at least one of the streams (QH, QL) is different than the other.
72. A headbox for a papermaking machine for distributing pulp suspension over the working width of the papermaking machine, comprising:
a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
a discharge nozzle, including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
flow means arranged upstream of the pulp suspension guide, the flow means having at least two sections, at least one section provided with at least two connections for the introduction of respective streams (QH, QL), at least one stream (QH, QL) having a pulp concentration, at least one of the connections of the at least one section including means for providing at least one of the respective streams (QH, QL) of the at least one section with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of the at least one section, in the at least one section of the flow means the streams (QH, QL) are mixed to form a mixed stream (QM), with a concentration (CM) which depends on the ratio of the volumetric flows of the streams (QH, QL), and each section of the flow means feeding at least one of the channels of the pulp suspension guide, said at least one section feeding at least one of the channels with the mixed stream (QM), the flow means further comprising an outlet for discharging of the mixed stream into the channels of the pulp suspension guide, and means maintaining the mixed stream (QM) of pulp suspension at a volumetric flow that is a constant during the adjustment of the ratio of the volumetric flows of the streams (QH, QL) for maintaining a desired fiber orientation cross profile in the paper web produced.
a pulp suspension guide having an upstream side, a downstream side and a plurality of separate channels therethrough for conducting pulp suspension from the upstream side to the downstream side;
a discharge nozzle, including a discharge outlet, the nozzle being located downstream of the downstream side of the pulp suspension guide, means for adjusting the concentration of the pulp suspension over the width of the discharge outlet to produce a desired basis weight cross profile of a paper web produced, said adjusting means comprising:
flow means arranged upstream of the pulp suspension guide, the flow means having at least two sections, at least one section provided with at least two connections for the introduction of respective streams (QH, QL), at least one stream (QH, QL) having a pulp concentration, at least one of the connections of the at least one section including means for providing at least one of the respective streams (QH, QL) of the at least one section with a predetermined throughput to adjust a ratio of the volumetric flows of the streams (QH, QL) of the at least one section, in the at least one section of the flow means the streams (QH, QL) are mixed to form a mixed stream (QM), with a concentration (CM) which depends on the ratio of the volumetric flows of the streams (QH, QL), and each section of the flow means feeding at least one of the channels of the pulp suspension guide, said at least one section feeding at least one of the channels with the mixed stream (QM), the flow means further comprising an outlet for discharging of the mixed stream into the channels of the pulp suspension guide, and means maintaining the mixed stream (QM) of pulp suspension at a volumetric flow that is a constant during the adjustment of the ratio of the volumetric flows of the streams (QH, QL) for maintaining a desired fiber orientation cross profile in the paper web produced.
73. The headbox of claim 72, wherein each of the streams (QH, QL) has a pulp concentration.
74. The headbox of claim 73, wherein the pulp concentration of at least one of the streams (QH, QL) is different than the other.
75. The headbox of claim 72, wherein the flow means has at least two sections each having at least two connections for the introduction of said streams (QH, QL).
76. A method for providing at least one of a selected basis weight cross profile and a selected fiber orientation cross profile over the width of a web of paper being manufactured in a paper making machine, wherein the machine includes a headbox having a plurality of separate suspension supply sections distributed along the width of the machine for supplying suspension for further processing into paper in the machine, and the machine further includes means following the headbox in the path of the suspension for processing the suspension to produce a paper web having a width along the width direction of the machine;
the method comprising:
supplying at least two partial streams to at least some of the sections of the headbox, wherein at least one of the partial streams to each of the headbox sections, that is being supplied by at least two partial streams, includes suspension, such that each section supplies a respective combined stream including suspension for further processing;
selectively controlling the volume per unit of time of at least one of the partial streams to each of the sections, that is being supplied by at least two partial streams, and also selectively controlling the volume per unit time of the combined stream from at least one of the sections that is being supplied by at least two partial streams for either varying the basis weight cross profile of the web without affecting the fiber orientation cross profile of the web, or varying the fiber orientation cross profile of the web without affecting the basis weight cross profile of the web, or varying both of the basis weight cross profile of the web and the fiber orientation cross profile of the web but with the variation of each such cross profile not affecting the other such cross profile; and further wherein the basis weight cross profile of the web is varied without affecting the fiber orientation cross profile of the web by adjusting the partial streams to each section for which the partial streams are adjusted in order to adjust the basis weight cross profile of the web, in a manner such that the total volume per unit of time of the combined stream supplied by each such section remains unchanged.
the method comprising:
supplying at least two partial streams to at least some of the sections of the headbox, wherein at least one of the partial streams to each of the headbox sections, that is being supplied by at least two partial streams, includes suspension, such that each section supplies a respective combined stream including suspension for further processing;
selectively controlling the volume per unit of time of at least one of the partial streams to each of the sections, that is being supplied by at least two partial streams, and also selectively controlling the volume per unit time of the combined stream from at least one of the sections that is being supplied by at least two partial streams for either varying the basis weight cross profile of the web without affecting the fiber orientation cross profile of the web, or varying the fiber orientation cross profile of the web without affecting the basis weight cross profile of the web, or varying both of the basis weight cross profile of the web and the fiber orientation cross profile of the web but with the variation of each such cross profile not affecting the other such cross profile; and further wherein the basis weight cross profile of the web is varied without affecting the fiber orientation cross profile of the web by adjusting the partial streams to each section for which the partial streams are adjusted in order to adjust the basis weight cross profile of the web, in a manner such that the total volume per unit of time of the combined stream supplied by each such section remains unchanged.
77. The method of claim 76, wherein the adjustment of partial streams to one section for adjusting the basis weight cross profile comprises increasing the volume per unit of time of one partial stream to the one section while decreasing the volume per unit of time of another partial stream to the one section.
78. The method of claim 76, wherein the fiber orientation cross profile of the web is varied without affecting the basis weight cross profile of the web by adjusting the volume per unit time of the combined stream to at least one of the sections without affecting the ratio of the volume per unit of time of the partial streams forming the combined stream to the at least one section.
79. The method of claim 78, wherein the volume per unit time of the partial streams to the at least one section are selectively all increased or all decreased to the respective extents for maintaining the ratio of the volumes per unit of time of the partial streams to the at least one section constant and thereby maintaining the basis weight cross profile constant.
80. The method of claim 76, wherein the fiber orientation cross profile of the web is varied without affecting the basis weight cross profile of the web by adjusting the volume per unit of time of the flow from at least one of the sections without affecting the volume per unit of time of the flow from at least some of the other sections and without affecting the density of the suspension in the flow from any of the sections including the at least one section.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4019593.7 | 1990-06-20 | ||
| DE4019593A DE4019593C2 (en) | 1990-06-20 | 1990-06-20 | Headbox for paper machines |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2045038A1 CA2045038A1 (en) | 1991-12-21 |
| CA2045038C true CA2045038C (en) | 2006-02-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002045038A Expired - Lifetime CA2045038C (en) | 1990-06-20 | 1991-06-20 | Headbox for papermaking machine with more uniform flow |
Country Status (6)
| Country | Link |
|---|---|
| EP (3) | EP0462472A1 (en) |
| JP (1) | JP3301623B2 (en) |
| AT (2) | ATE214442T1 (en) |
| CA (1) | CA2045038C (en) |
| DE (3) | DE4019593C2 (en) |
| FI (2) | FI912230A (en) |
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| DE10122047A1 (en) * | 2001-05-07 | 2002-11-14 | Voith Paper Patent Gmbh | Sheet forming device and method |
| DE10208610B4 (en) * | 2002-02-27 | 2014-03-06 | Voith Patent Gmbh | Method for distributing a pulp suspension in the headbox of a paper or board machine and headbox |
| DE10211178A1 (en) * | 2002-03-14 | 2003-09-25 | Voith Paper Patent Gmbh | Laminated outlet for production of sandwich plaster board or corrugated cardboard has bends in channel sidewalls to jet outlet |
| DE10232125A1 (en) * | 2002-07-16 | 2004-02-05 | Voith Paper Patent Gmbh | Sieve section for the production of a multi-layer fibrous web |
| DE10234559A1 (en) * | 2002-07-30 | 2004-02-19 | Voith Paper Patent Gmbh | Papermaking machine for low-volume paper or carton has vortex generator block made of a single integral plastic unit with jets discharging to sieve belt |
| DE10317720A1 (en) * | 2003-04-17 | 2005-02-17 | Voith Paper Patent Gmbh | headbox |
| DE10331039A1 (en) * | 2003-07-09 | 2005-01-27 | Voith Paper Patent Gmbh | headbox |
| DE10331040A1 (en) * | 2003-07-09 | 2005-01-27 | Voith Paper Patent Gmbh | Papermaking assembly fibre suspension headbox has throttle control of dilution mechanism in outer margin |
| DE10333977A1 (en) * | 2003-07-25 | 2005-02-10 | Voith Paper Patent Gmbh | headbox |
| DE10335752A1 (en) * | 2003-08-05 | 2005-03-03 | Voith Paper Patent Gmbh | Headbox for production of paper or carton web has horizontal cell lines with vortex generators discharging through the jet via parallel horizontal arrays of slats |
| DE10351295A1 (en) * | 2003-10-31 | 2005-06-02 | Voith Paper Patent Gmbh | Method for producing a fibrous web and apparatus for carrying out the method |
| DE10355687A1 (en) * | 2003-11-28 | 2005-06-23 | Voith Paper Patent Gmbh | Process for producing a fibrous web |
| DE10358216A1 (en) * | 2003-12-12 | 2005-07-21 | Voith Paper Patent Gmbh | Method and device for controlling at least one process-relevant property during the production of a fibrous web |
| DE202004021817U1 (en) | 2004-10-21 | 2011-06-09 | Voith Patent GmbH, 89522 | Sheet forming system |
| DE102007033395A1 (en) | 2007-07-18 | 2009-02-19 | Voith Patent Gmbh | Schrägsiebformer a machine for producing a fibrous web of at least one pulp suspension |
| DE102008000435A1 (en) | 2008-02-28 | 2009-09-03 | Voith Patent Gmbh | Schrägsiebformer a machine for producing a fibrous web of at least one pulp suspension |
| DE102008043358A1 (en) | 2008-10-31 | 2010-05-06 | Voith Patent Gmbh | Method and device for web transfer |
| EP2199459A1 (en) | 2008-12-16 | 2010-06-23 | Voith Patent GmbH | Sheet composition system for a machine for producing a multiple layer sheet of fibrous material |
| DE102008055184A1 (en) | 2008-12-30 | 2010-07-01 | Voith Patent Gmbh | Method and device for controlling the moisture cross profile in the area of the wire section |
| DE102009000696A1 (en) | 2009-02-06 | 2010-08-12 | Voith Patent Gmbh | Method for producing a multilayer fibrous web and sheet forming apparatus for carrying out the method |
| DE102009003148A1 (en) | 2009-05-15 | 2010-11-18 | Voith Patent Gmbh | Method for compensating variations in operation mode of machine for producing fibrous web e.g. paper web, involves controlling actuators for producing reaction, which counter acts variations caused by agent |
| DE102009027079A1 (en) | 2009-06-22 | 2010-12-23 | Voith Patent Gmbh | Headbox for a machine for producing a fibrous web |
| DE102009046968A1 (en) | 2009-11-23 | 2011-05-26 | Voith Patent Gmbh | headbox |
| DE102010029601A1 (en) | 2010-06-01 | 2011-12-01 | Voith Patent Gmbh | Method for checking the condition of closed valve systems for assessing the condition of maintenance |
| DE102010029602A1 (en) | 2010-06-01 | 2011-12-01 | Voith Patent Gmbh | Positioning drive and positioning drive system |
| DE102011078925A1 (en) | 2011-07-11 | 2013-01-17 | Voith Patent Gmbh | Method for setting uniform property transverse profile of e.g. paper in headbox of fibrous web manufacturing machine, involves integrating basis weight cross profile and fiber orientation cross profile in respective control circuits |
| DE102011082836A1 (en) | 2011-09-16 | 2013-03-21 | Voith Patent Gmbh | Method for controlling and regulating a paper machine |
| DE102011082914A1 (en) | 2011-09-19 | 2013-03-21 | Voith Patent Gmbh | Wire section for a machine for producing a fibrous web |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2942966C2 (en) * | 1979-10-24 | 1984-04-26 | J.M. Voith Gmbh, 7920 Heidenheim | Headbox nozzle |
| DE3244055A1 (en) * | 1981-12-08 | 1983-07-21 | ASEA AB, 72183 Västeraas | Arrangement for controlling the fibre concentration in a fibre suspension |
| DE3514554C3 (en) * | 1984-09-19 | 1998-01-08 | Escher Wyss Gmbh | Headbox device for a paper machine and method for its operation |
| DE3535849A1 (en) * | 1985-10-08 | 1987-04-09 | Voith Gmbh J M | Setting device for the lip of a papermachine hatbox |
| DE3628699A1 (en) * | 1986-08-23 | 1988-03-03 | Voith Gmbh J M | FABRIC DRAIN |
| FR2631353A1 (en) * | 1988-05-13 | 1989-11-17 | Semti | PASTA MIXED FEEDING DEVICE |
-
1990
- 1990-06-20 DE DE4019593A patent/DE4019593C2/en not_active Expired - Lifetime
-
1991
- 1991-05-08 FI FI912230A patent/FI912230A/en unknown
- 1991-06-08 AT AT96120331T patent/ATE214442T1/en not_active IP Right Cessation
- 1991-06-08 EP EP91109409A patent/EP0462472A1/en not_active Ceased
- 1991-06-08 EP EP96120331A patent/EP0785305B1/en not_active Revoked
- 1991-06-08 AT AT97101711T patent/ATE227370T1/en not_active IP Right Cessation
- 1991-06-08 DE DE59109243T patent/DE59109243D1/en not_active Revoked
- 1991-06-08 EP EP97101711A patent/EP0789107B1/en not_active Revoked
- 1991-06-08 DE DE59109230T patent/DE59109230D1/en not_active Revoked
- 1991-06-19 JP JP17460891A patent/JP3301623B2/en not_active Expired - Lifetime
- 1991-06-20 CA CA002045038A patent/CA2045038C/en not_active Expired - Lifetime
-
2002
- 2002-04-24 FI FI20020790A patent/FI20020790A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JP3301623B2 (en) | 2002-07-15 |
| JPH04333688A (en) | 1992-11-20 |
| CA2045038A1 (en) | 1991-12-21 |
| DE4019593C2 (en) | 1994-01-20 |
| EP0785305A1 (en) | 1997-07-23 |
| EP0462472A1 (en) | 1991-12-27 |
| DE4019593A1 (en) | 1992-01-09 |
| DE59109230D1 (en) | 2002-04-18 |
| ATE227370T1 (en) | 2002-11-15 |
| DE59109243D1 (en) | 2002-12-12 |
| EP0789107B1 (en) | 2002-11-06 |
| EP0789107A2 (en) | 1997-08-13 |
| EP0785305B1 (en) | 2002-03-13 |
| EP0789107A3 (en) | 2000-01-19 |
| FI912230A (en) | 1991-12-21 |
| FI20020790A (en) | 2002-04-24 |
| FI912230A0 (en) | 1991-05-08 |
| ATE214442T1 (en) | 2002-03-15 |
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| EEER | Examination request | ||
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