CA2258232C - Equipment for combining a dilution flow with the stock flow passed out of the inlet header in a paper/board machine - Google Patents
Equipment for combining a dilution flow with the stock flow passed out of the inlet header in a paper/board machine Download PDFInfo
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- CA2258232C CA2258232C CA002258232A CA2258232A CA2258232C CA 2258232 C CA2258232 C CA 2258232C CA 002258232 A CA002258232 A CA 002258232A CA 2258232 A CA2258232 A CA 2258232A CA 2258232 C CA2258232 C CA 2258232C
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- flow
- dilution
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- stock
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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
- D21F1/022—Means for injecting material into flow within the headbox
-
- 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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- Paper (AREA)
Abstract
The invention concerns an equipment for combining a dilution flow (L1) with the stock flow (L2) passed out of the inlet header (J1) in a paper/board machine.
The equipment comprises dilution flow ducts (D1, D2...), through which the dilution flow (L1) is passed to the desired location across the width of the headbox of the paper/board machine so as to regulate the basis weight of the paper/board web to the desired level. The dilution flow duct (D1, D2...) is constructed in such a way in its final end (D1a, D2a...) that it becomes narrower towards its end. Branch ducts (E1.1, E1.2...; E2.1, E2.2...) are placed in the area of said narrowing, out of which branch ducts the dilution flow is passed into the system of pipes (11, G), in which the dilution flow is combined with the stock flow (L2) passed out of the inlet header (J1).
The equipment comprises dilution flow ducts (D1, D2...), through which the dilution flow (L1) is passed to the desired location across the width of the headbox of the paper/board machine so as to regulate the basis weight of the paper/board web to the desired level. The dilution flow duct (D1, D2...) is constructed in such a way in its final end (D1a, D2a...) that it becomes narrower towards its end. Branch ducts (E1.1, E1.2...; E2.1, E2.2...) are placed in the area of said narrowing, out of which branch ducts the dilution flow is passed into the system of pipes (11, G), in which the dilution flow is combined with the stock flow (L2) passed out of the inlet header (J1).
Description
Equipment for combining a dilution flow with the stock flow passed out of the inlet header in a paperboard machine The invention concerns an equipment for combining a dilution flow with the stock flow passed out of the inlet header in a paperboard machine.
From the applicant's earlier patent applications FI 901593, FI 933027 and FI
942780, a what is called dilution headbox is known, which is understood as a headbox construction in which the basis weight of the web can be regulated across the web width by through valves passing a dilution flow to different locations of width of the headboX and by regulating the quantity of said flow. The dilution flow is mixed with the stock flow passed out of the inlet header of the headbox.
The dilution flow can consist of pure or fibrous liquid. Thus, the dilution water can be, for example, wire water taken as retention from the web.
In the present patent application, an equipment is described for combining a dilution flow with the stock flow derived from the inlet header of a paperboard machine, in which solution of equipment the dilution liquid, preferably dilution water, is passed into connection with the stock flow passed from the inlet header preferably in connection with the tube manifold placed after the inlet header. In the headbox construction in accordance with the invention, the basis weight of the web can be regulated across the wire width by through regulation valves V1,V2... passing the desired dilution flow to different locations across the width of the headbox.
In the solution in accordance with the invention the dilution flow is passed into each row of pipes in the tube manifold and in each row of pipes into all the pipes placed one above the other in the row of pipes. In this way the mixing of the dilution flow with the stock flow passed out of the inlet header can be made as efficient as possible. In accordance with the invention, the dilution flow duct consists of a resilient pipe passed from the valve, which pipe is preferably connected with the tube manifold and out of which pipe the flow is distributed through a duct portion with inclined walls uniformly into each pipe in the rows of pipes in the tube manifold. When a narrowing duct end is employed, the flow can be distributed evenly into all the pipes in the row of pipes in the tube manifold, also into the first pipe in the direction of flow Ll of the dilution liquid. A poorly distributed dilution flow increases the instability/residual scattering of the basis weight of the paperboard.
In accordance with the invention, the narrowing duct portion for the dilution flow has been formed into a middle plate component so that one wall of the narrowing duct portion consists of a plate which is placed as the first plate in the flow direction Lz of the stock flow and which contains the flow ducts for the stock flow.
Further, in the construction, at the outlet side of the plate that contains the duct portion narrowing in the flow direction, a separate throttle plate is employed, which comprises throttle openings, in which connection the combined flow L1 + L2 is mixed efficiently after the point of introduction of the dilution flow at said throttle point. In the present patent application, when a throttle plate is spoken of, said plate can also refer to a plate construction that comprises a resistance to flow in general for the combined flow L1 + L2. Thus, the throttle can also be substituted for by a flow widening. The effect of said widening on the conduct of the combined flow + L2 is similar to the effect of a throttle construction.
The duct in accordance with the invention, which becomes narrower at its end, has been made most advantageously by machining, preferably milling, the duct into a metal plate. The set of flow pipes which produces turbulence in the flow and which comprises a step-like widening or narrowing, preferably the tube manifold placed right after the stock inlet header or the turbulence generator placed after an inter-mediate chamber, has been formed into one blank plate by drilling said flow pipes into said plate. Similarly, in a construction in accordance with the invention, the ends of the dilution liquid duct have been formed into said single plate by machining a narrowing duct end into the construction, out of which narrowing duct end the branch ducts are branched to the flow pipes intended for the stock flow.
In accordance with one aspect of the present invention, there is provided in an arrangement for combining a flow of dilution liquid with a flow of stock from an inlet header of a headbox of a paperboard machine, the arrangement including conduit means for passing the stock flow from the inlet header and dilution flow ducts through which the dilution liquid is passed, the conduit means comprising a plurality of conduits extending across a width of the headbox, the improvement comprising at least one of the dilution flow ducts being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by the walls at the upstream end being greater than a cross-sectional area defined by the walls at the downstream end, each of the dilution flow ducts being in flow communication with at least two of the conduits at one of a plurality of discrete locations across the width of the headbox such that the basis weight of a paperboard web formed upon discharge from the headbox is regulatable, and at least two branch ducts in flow communication with the narrowing duct portion of each of the at least one dilution flow duct, each of the branch ducts leading to a respective one of the at least two conduits.
In an embodiment of the invention, the ducts in the set of flow pipes, which comprises a stepwise widening/widenings producing turbulence in the flow, preferably in the tube manifold or in the turbulence generator, are composed of module-like units, in which connection the pipes in the tube manifold have been made into each module by turning and, moreover, into each module, the end of the dilution flow duct has been made by milling the end onto the front face of the module. When the modules are formed in the way mentioned above by drilling and milling and when the modules are assembled side by side, a unit of construction is obtained which can be constructed easily.
The throttle placed in th.e tube manifold directly after the point of introduction of the dilution fluid has been made by turning a conical hole into the metal plate construction.
The arrangement of supply of dilution liquid in accordance with the invention and its modular nature are suitable in particular for the supply of the dilution liquid into connection with the tube manifold. The invention is, however, not supposed to be confined to the point of supply of dilution liquid mentioned above alone, but the dilution liquid can be introduced into a similar construction also at the rear side of the intermediate chamber in connection with the turbulence generator.
3a In accordance with another aspect of the present invention, there is provided claim a method for combining a flow of dilution liquid with a flow of stock from an inlet header of a headbox of a paperboard machine at a location between the inlet header and a slice chamber of the headbox, comprising the steps of passing the stock flow from the inlet header through conduit means comprising a plurality of conduits extending across a width of the headbox, passing dilution liquid through a plurality of dilution flow ducts each in flow communication with at least two of the conduits situated at a discrete position along the width of the headbox, each of the dilution flow ducts being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectic>nal area defined by the walls at the upstream end being greater than a cross-sectional area defined by the walls at the downstream end, and passing the dilution liquid from each of the dilution flow ducts through at least two branch ducts in flow communication with the narrowing duct portion of the dilution flow duct and into a respective one of the at least two conduits.
In accordance with a further aspect of the present invention, there is provided a method for regulating the basis weight of a web upon its discharge from a headbox of a paperboard machine, comprising the steps of passing a stock flow from an inlet header of the headbox through conduit means comprising a plurality of conduits extending across a width of the headbox, introducing dilution liquid into the stock flow in at least one of the conduits by passing the dilution liquid through at least one of a plurality of dilution flow ducts each leading to at least two of the conduits situated at a discrete position along the width of the headbox, the at least one dilution flow duct being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by the walls at the upstream end being greater than a cross-sectional area defined by the walls at the downstream end, and passing the dilution liquid from the at least one dilution flow duct through at least two branch ducts in flow communication with the narrowing duct portion of the at least one dilution flow duct and into one of the conduits, regulating the flow of the dilution liquid through the dilution flow ducts 1;o thereby regulate the basis weight of the web, and discharging the stock flow including the dilution liquid from the headbox to form the web.
3b The invention will be described in the following with reference to some preferred embodiments of the invention illustrated in the figures in the accompanying drawings, the invention being, however, not supposed to be confined to said embodiments alone.
Figure 1A is a sectional view of the headbox of a paperboard machine, and what is shown is th.e arrangement of supply of dilution liquid in connection with the tube manifold placed after the inlet header.
Figure 1B is an illustration in part of the construction of Fig. 1A from above.
Figure 1C shows the set of valves V1,V2... for the regulation of the dilution liquid viewed in the direction of the arrow K1 in Fig. 1A.
Figure 2 is a sectional view taken along the line I-I in Fig. 1B. What is shown is the supply of dilution liquid into connection with the tube manifold on a larger scale.
Figure 3 is an axonometric view of modular construction components M1 and M2.
Figure 4A is an illustration in part of the module M1 shown in Fig. 3 viewed in the area of the tube manifold in the direction of the arrow K2 in Fig. 3.
Figure 4B is a sectional view taken along the line II-II in Fig. 4A.
Figure 4C is a sectional view taken along the line III-III in Fig. 4A.
Figure 4D shows a throttle plate placed at the outlet side of the tube manifold (in the flow direction of the stock). The illustration is substantially similar to the sectional view shown in Fig. 4B.
Figure 5 shows an embodiment of the invention which is in the other respects similar to the sectional view of Fig. 4C, except that in this embodiment the branch ducts E1.1~E1.2~E1.3 have been milled into the construction so that the flow is directed against the stock flow L1. In this way the mixing of the flows can be made efficient.
Figure 6A shows a second embodiment of the arrangement of supply of dilution liquid.
Figure 6B is a sectional view taken along the line IV-IV in Fig. 6A.
Figure 7A shows an embodiment of the invention in which one structural wall of the conically narrowing duct D1 is formed by a side wall of an adjacent module.
Figure 7B is a sectional view taken along the line V-V in Fig. 7A.
Figure 8A shows an embodiment of the invention in which the supply of the dilution liquid into the stock flow takes place in the turbulence generator after an intermedi-5 ate chamber, Figure 8B shows the construction of Fig. 8A viewed from above.
Figure 9 shows an embodiment of the construction in accordance with the invention in which the stock ducts and the dilution liquid ducts have been made into one single plate by machining. The plate extends across the entire width of the headbox.
As is shown in Fig. 1A, the headbox 10 of the paperboard machine comprises an inlet header J, after the inlet header J a system of pipes, i.e. a set of pipes 11 of the tube manifold, which produces turbulence in the stock flow, and after the set of pipes an intermediate chamber 12, which is opened into the stilling chamber 13.
After the intermediate chamber 12, there is a second set of pipes which produces turbulence in the stock flow, i. e. the turbulence generator G . The pipes G
1,1, G 1 .2 in the turbulence generator G are further opened into the slice cone 16, which comprises lamellae 17a1,17a2,17a3 in the way shown in the figure. The stock is passed further out of the slice cone 16 through an outflow gap onto the forming wire H. As is shown in the figure, the outflow opening after the slice cone 16 comprises a top slice bar n and a mechanism 18 for its regulation. The position of the top slice bar n can be regulated by means of the adjustment spindles 19 and adjustment motors 20 included in the regulation mechanism 18. The flow Ll of the dilution liquid is regulated by means of the valves V 1, V2. . . The equipment comprises a . number of distribution ducts D~,D2... for dilution flow across the width of the headbox, in which connection the desired dilution flows can be introduced into different locations of width across the headbox, and said flows can be regulated at each location of width by regulating the valve V 1, V2. . . of the dilution flow. As is shown in Fig. 1A, the dilution liquid, preferably dilution water, is passed into different locations of width across the headbox of the paper machine so that the dilution water is passed into the pipes llal,i,llal.2,11a1..~;Ila2.l,11a2.2,11a2,3;
lla3.l,lla3.~,11a3.3 ... in each vertical row in the tube manifold 11.
Fig. 1B illustrates the construction as shown in Fig. 1A viewed from above.
Fig. 1 C illustrates the system of valves V 1, V2, V3 . . . used in the regulation of the dilution liquid. The dilution liquid is passed from the dilution liquid inlet header J2 into the dilution liquid supply ducts D 1,D2. . . through the valves V ~ , V2.
. . By means of the valves, the flow of the dilution liquid L1 is regulated in each duct D1,D2...
independently from the other ducts.
Fig. 2 is a sectional view taken along the line I-I in Fig. 1B. As is shown in the figure, from the inlet header J 1 a stock flow L 1 is passed into each pipe 11 a 1.1, llal.2,l1a1.3;11a2.l,l1a2.2,11a2_3; lla3.i,l1a3,2,11a3.3 ... in the tube manifold 11.
The dilution liquid is passed as a dilution flow I2 into each pipe llat.l,llal.2, 11a1.3 in a vertical row in the tube manifold. The flow is passed through the distribution duct D1 or equivalent of the distribution pipe into the vertical row in the tube manifold 11 and further into each pipe 11 a 1.1,11 a 1,2,11 a 1.3 in each vertical row. Similarly, in the other different locations of width and vertical sections in the tube manifold, the dilution flow is passed out of the distribution ducts D2,D3... into the pipes lla2.i,l1a2.2,11a2,3;11a3.l,l1a3.2,11a3,3 ... in the vertical rows at corresponding locations in the tube manifold 11.
As is shown in Fig. 2, the distribution duct D1,D2 for dilution flow becomes narrower at its end so that the narrowing of the duct D 1 takes place towards the lowest pipe llal_3 in the tube manifold 11. As is illustrated in Fig. 2 by means of dashed lines, the duct portion Dla of the duct Di, which has been formed between the rows of pipes in the system of pipes, has additionally been formed so that its wall portion S 1 is placed as inclined in relation to the vertical plane. The branch ducts are opened from the wall S2 of the duct portion Dla into the pipes llal.i, 11a1.2... in the vertical rows in the set of pipes 11.
By means of said narrowing arrangement of ducts, the pressure can be kept invari-able in all the outlets E1.~,E1,2,E1.3 of fhe duct D1. As is shown in the figure, the cross-sectional shape of the distribution ducts E1.1,E1.2,Et.3 branched from the dilution flow duct D~ is rectangular.
Similarly, the cross-sectional shape of the end Dla of the duct D1 is rectangular, and said narrowing duct shape is produced by milling the end wall S1, which is placed inclined in relation to the vertical plane, in the end area of the duct D 1.
The duct D 1 portion Dla is connected with a resilient flexible duct portion Dlb, which comprises a regulation valve V 1 at its end. The dilution liquid is passed into the duct D 1 out of the dilution liquid inlet header J2.
The outlets of the branch ducts E1.1,E1.2~E1.3 into the pipes llal.l,llal.2,l1a1.3 in the tube manifold 11 are placed at the forward side of the throttle 21a1,~,21a1.2, 21a1,3 in relation to the flow direction L1. The throttle 21a1.1,21a1.2,21a1,3 is a conical contraction of the duct, which terminates in a straight duct portion 22a1.1, 22a1.2,22a~.3 (FIG. 4D). The most usual embodiment is a construction in which there is one single plate into which the pipes llal,l,llal,2,l1a1,3...;
lla2.l,11a2.2, l 1a2.3... formed into said plate of the tube manifold 11 have been made by drilling, the branch ducts E1.1,E1.2~E1.3 having been made into the front face T' of said plate by machining.
The pipes llal.l,llal.2,l1a1.3...; 11a2.1,11a2,2, 11a2,3... in the tube manifold 11 consist of two portions of sets of pipes, i.e. of pipes that have been machined, preferably drilled, into a separate plate and of separate pipe components connected with said pipes.
Fig. 3 illustrates the modular structural components M1 and M2 in the mixing part of the tube manifold 11. ' The structural components or modules M ~ , M2. . .
are preferably metallic plates T, into which the pipes llal.l,llal_2,1ia1.3 in the initial part of the tube manifold 11 have been made by drilling into the plate T. As each module M t ,M2 has been made as a separate structural component, the ducts D
1, D2. . . can be made into it, onto the front faces T' of the modules M 1, M2. .
. , easily by milling. Similarly, the duct D1,D2 shape narrowing towards the end in the end portions Dla,D2a... of the ducts can be accomplished by making the end wall S1 of the duct D1,D2..., whose cross-sectional shape is otherwise rectangular, inclined in the area of the end portion Dla,D2a... Similarly, the branch ducts E1_1,E1.2~E1.3~~~e E2.1 ~E2.2~E2.3~ ~ ~ ~ E3.1 ~E3.2~E3.3 ~ ~ ~ can be made easily by milling into the front wall T' of the plate T of each module M 1,M2. . .
In the embodiment shown in the figure, the ducts E1.1,E1.2~E1.3 are placed perpen-dicularly to the central axes X1_1,X1.2~X1.3 of the pipes llal.l,llal_2,11a1,3 in the tube manifold. In such a case the flows Ll and L2 meet each other at a right angle.
Fig. 4A shows the module M1 viewed in the direction of the arrow K2 in Fig. 3.
Fig. 4B is a sectional view taken along the line II-II in Fig. 4A.
Fig. 4C is a sectional view taken along the line III-III in Fig. 4A.
The illustrations in Figs. 4B and 4C do not show the throttle plate 20, but the fitting of said plate in connection with the construction is illustrated in Fig. 4D.
Fig. 4D shows the throttle plate 20 in connection with the front part, i.e.
the plate T, in the tube manifold 11. At the outlet side of the throttle plate 20, the separate pipes in the final part of the tube manifold 11 are placed, as is shown in Fig. 2.
Fig. 5 shows a second embodiment of the invention, which is in the other respects similar to the sectional view in Fig. 4C, except that in said embodiment the branch ducts E1.1,E1.Z~E1.3 have been milled into the construction so that the flow direction of the flow L1 out of the duct D1 can be directed so that it is oblique against the flow L2 coming from the inlet header J1. In such a case the mixing of the dilution flow L~ and the stock flow L2 can be made efficient.
The embodiment of Fig. 5 is mainly similar to the sectional view in Fig. 4C.
Fig. 6A shows an embodiment of the invention in which the duct portions Dla, D2a... of the ducts D1,D2... have been formed into a construction plate 50, which is placed alongside the throttle plate 20 and so that the narrowing duct portion Dla, D2a... is fitted to be opened so from the front face T" of the plate 50 that the cleaning of the duct system Dla,D2a... can be carried out by detaching a separate plate 60, which contains the initial part of the system of flow ducts (llal.l,l 1a1.2...;
11 a2.1,11 a2.2 . . . ; G 1.1 ~ G 1.2 ~ ~ ~ ~ G2.1 ~ G2.2 ~ ~ ~ ) intended for the flow L2 coming from the inlet header J1. Thus, when the plate 60 is detached, the narrowing ducts Dla~D2a~ ~ ~ and the connected branch ducts El.1,E1.2~ ~ ~ are opened for cleaning, and the extension portion Dlb,D2b... connected with the narrowing duct Dla,D2a...
does not interfere with the washing of the system of ducts, but said washing can be carried out by detaching the plate 60.
Fig. 6B is a sectional view taken along the line IV-IV in Fig. 6A.
Fig. 7A illustrates a plate-like module M1,M2 in accordance with the invention. The illustration in Fig. 7A is taken mainly in the direction of the arrow K2 in Fig. 3. The embodiment of Fig. 7A differs from that of Fig. 3 mainly in the respect that one side wall of the adjacent modular structural components, i.e. of the modules M1,M2, is defined by the duct D1,D2... What is shown is an embodiment in which one wall S4 of the conical portion DIa,D2a... of the duct D1,D2... is formed by one side wall F1 of the module M2 adjacent to said module M1. The initial part of the tube manifold 11 has been formed out of plate-like modules Ml,M2,M3... by intercon-necting said modules M1,M2,M3... in the direction of width of the headbox of the paperboard machine.
Fig. 7B is a sectional view taken along the line V-V in Fig. 7A.
Fig. 8A shows an embodiment of the invention in which the mixing of the dilution liquid and the stock flow takes place after the intermediate chamber 12 in the turbulence generator G at the forward end of its pipes G1.1,G1.2'G1.3~ ~ ~ ~
G2.1'G2.2' G2.3... in a way similar to the solution described above.
Fig. 8B shows the construction of Fig. 8A viewed from above in the area of the 5 forward end of the turbulence generator G.
Fig. 9 is an illustration in part of an embodiment of the invention which comprises narrowing ducts D 1,D2. . . for dilution liquid in connection with a tube manifold 11 composed of a single plate-like structural component T. The pipes in the tube 10 manifold 11 can have been made into a metallic plate construction conventionally by machining, preferably drilling. The ducts D1,D2... that supply dilution liquid have been made into the front face of the plate construction T, as was the case in the embodiments described above, by milling or by means of some other method of machining. The plate T extends across the entire width of the headbox. The con-struction can also be used in connection with the turbulence generator, after the intermediate chamber, or it can be used in a headbox construction which comprises, after the inlet header J1, just one system of pipes that produces turbulence and, after that, the slice cone.
From the applicant's earlier patent applications FI 901593, FI 933027 and FI
942780, a what is called dilution headbox is known, which is understood as a headbox construction in which the basis weight of the web can be regulated across the web width by through valves passing a dilution flow to different locations of width of the headboX and by regulating the quantity of said flow. The dilution flow is mixed with the stock flow passed out of the inlet header of the headbox.
The dilution flow can consist of pure or fibrous liquid. Thus, the dilution water can be, for example, wire water taken as retention from the web.
In the present patent application, an equipment is described for combining a dilution flow with the stock flow derived from the inlet header of a paperboard machine, in which solution of equipment the dilution liquid, preferably dilution water, is passed into connection with the stock flow passed from the inlet header preferably in connection with the tube manifold placed after the inlet header. In the headbox construction in accordance with the invention, the basis weight of the web can be regulated across the wire width by through regulation valves V1,V2... passing the desired dilution flow to different locations across the width of the headbox.
In the solution in accordance with the invention the dilution flow is passed into each row of pipes in the tube manifold and in each row of pipes into all the pipes placed one above the other in the row of pipes. In this way the mixing of the dilution flow with the stock flow passed out of the inlet header can be made as efficient as possible. In accordance with the invention, the dilution flow duct consists of a resilient pipe passed from the valve, which pipe is preferably connected with the tube manifold and out of which pipe the flow is distributed through a duct portion with inclined walls uniformly into each pipe in the rows of pipes in the tube manifold. When a narrowing duct end is employed, the flow can be distributed evenly into all the pipes in the row of pipes in the tube manifold, also into the first pipe in the direction of flow Ll of the dilution liquid. A poorly distributed dilution flow increases the instability/residual scattering of the basis weight of the paperboard.
In accordance with the invention, the narrowing duct portion for the dilution flow has been formed into a middle plate component so that one wall of the narrowing duct portion consists of a plate which is placed as the first plate in the flow direction Lz of the stock flow and which contains the flow ducts for the stock flow.
Further, in the construction, at the outlet side of the plate that contains the duct portion narrowing in the flow direction, a separate throttle plate is employed, which comprises throttle openings, in which connection the combined flow L1 + L2 is mixed efficiently after the point of introduction of the dilution flow at said throttle point. In the present patent application, when a throttle plate is spoken of, said plate can also refer to a plate construction that comprises a resistance to flow in general for the combined flow L1 + L2. Thus, the throttle can also be substituted for by a flow widening. The effect of said widening on the conduct of the combined flow + L2 is similar to the effect of a throttle construction.
The duct in accordance with the invention, which becomes narrower at its end, has been made most advantageously by machining, preferably milling, the duct into a metal plate. The set of flow pipes which produces turbulence in the flow and which comprises a step-like widening or narrowing, preferably the tube manifold placed right after the stock inlet header or the turbulence generator placed after an inter-mediate chamber, has been formed into one blank plate by drilling said flow pipes into said plate. Similarly, in a construction in accordance with the invention, the ends of the dilution liquid duct have been formed into said single plate by machining a narrowing duct end into the construction, out of which narrowing duct end the branch ducts are branched to the flow pipes intended for the stock flow.
In accordance with one aspect of the present invention, there is provided in an arrangement for combining a flow of dilution liquid with a flow of stock from an inlet header of a headbox of a paperboard machine, the arrangement including conduit means for passing the stock flow from the inlet header and dilution flow ducts through which the dilution liquid is passed, the conduit means comprising a plurality of conduits extending across a width of the headbox, the improvement comprising at least one of the dilution flow ducts being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by the walls at the upstream end being greater than a cross-sectional area defined by the walls at the downstream end, each of the dilution flow ducts being in flow communication with at least two of the conduits at one of a plurality of discrete locations across the width of the headbox such that the basis weight of a paperboard web formed upon discharge from the headbox is regulatable, and at least two branch ducts in flow communication with the narrowing duct portion of each of the at least one dilution flow duct, each of the branch ducts leading to a respective one of the at least two conduits.
In an embodiment of the invention, the ducts in the set of flow pipes, which comprises a stepwise widening/widenings producing turbulence in the flow, preferably in the tube manifold or in the turbulence generator, are composed of module-like units, in which connection the pipes in the tube manifold have been made into each module by turning and, moreover, into each module, the end of the dilution flow duct has been made by milling the end onto the front face of the module. When the modules are formed in the way mentioned above by drilling and milling and when the modules are assembled side by side, a unit of construction is obtained which can be constructed easily.
The throttle placed in th.e tube manifold directly after the point of introduction of the dilution fluid has been made by turning a conical hole into the metal plate construction.
The arrangement of supply of dilution liquid in accordance with the invention and its modular nature are suitable in particular for the supply of the dilution liquid into connection with the tube manifold. The invention is, however, not supposed to be confined to the point of supply of dilution liquid mentioned above alone, but the dilution liquid can be introduced into a similar construction also at the rear side of the intermediate chamber in connection with the turbulence generator.
3a In accordance with another aspect of the present invention, there is provided claim a method for combining a flow of dilution liquid with a flow of stock from an inlet header of a headbox of a paperboard machine at a location between the inlet header and a slice chamber of the headbox, comprising the steps of passing the stock flow from the inlet header through conduit means comprising a plurality of conduits extending across a width of the headbox, passing dilution liquid through a plurality of dilution flow ducts each in flow communication with at least two of the conduits situated at a discrete position along the width of the headbox, each of the dilution flow ducts being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectic>nal area defined by the walls at the upstream end being greater than a cross-sectional area defined by the walls at the downstream end, and passing the dilution liquid from each of the dilution flow ducts through at least two branch ducts in flow communication with the narrowing duct portion of the dilution flow duct and into a respective one of the at least two conduits.
In accordance with a further aspect of the present invention, there is provided a method for regulating the basis weight of a web upon its discharge from a headbox of a paperboard machine, comprising the steps of passing a stock flow from an inlet header of the headbox through conduit means comprising a plurality of conduits extending across a width of the headbox, introducing dilution liquid into the stock flow in at least one of the conduits by passing the dilution liquid through at least one of a plurality of dilution flow ducts each leading to at least two of the conduits situated at a discrete position along the width of the headbox, the at least one dilution flow duct being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by the walls at the upstream end being greater than a cross-sectional area defined by the walls at the downstream end, and passing the dilution liquid from the at least one dilution flow duct through at least two branch ducts in flow communication with the narrowing duct portion of the at least one dilution flow duct and into one of the conduits, regulating the flow of the dilution liquid through the dilution flow ducts 1;o thereby regulate the basis weight of the web, and discharging the stock flow including the dilution liquid from the headbox to form the web.
3b The invention will be described in the following with reference to some preferred embodiments of the invention illustrated in the figures in the accompanying drawings, the invention being, however, not supposed to be confined to said embodiments alone.
Figure 1A is a sectional view of the headbox of a paperboard machine, and what is shown is th.e arrangement of supply of dilution liquid in connection with the tube manifold placed after the inlet header.
Figure 1B is an illustration in part of the construction of Fig. 1A from above.
Figure 1C shows the set of valves V1,V2... for the regulation of the dilution liquid viewed in the direction of the arrow K1 in Fig. 1A.
Figure 2 is a sectional view taken along the line I-I in Fig. 1B. What is shown is the supply of dilution liquid into connection with the tube manifold on a larger scale.
Figure 3 is an axonometric view of modular construction components M1 and M2.
Figure 4A is an illustration in part of the module M1 shown in Fig. 3 viewed in the area of the tube manifold in the direction of the arrow K2 in Fig. 3.
Figure 4B is a sectional view taken along the line II-II in Fig. 4A.
Figure 4C is a sectional view taken along the line III-III in Fig. 4A.
Figure 4D shows a throttle plate placed at the outlet side of the tube manifold (in the flow direction of the stock). The illustration is substantially similar to the sectional view shown in Fig. 4B.
Figure 5 shows an embodiment of the invention which is in the other respects similar to the sectional view of Fig. 4C, except that in this embodiment the branch ducts E1.1~E1.2~E1.3 have been milled into the construction so that the flow is directed against the stock flow L1. In this way the mixing of the flows can be made efficient.
Figure 6A shows a second embodiment of the arrangement of supply of dilution liquid.
Figure 6B is a sectional view taken along the line IV-IV in Fig. 6A.
Figure 7A shows an embodiment of the invention in which one structural wall of the conically narrowing duct D1 is formed by a side wall of an adjacent module.
Figure 7B is a sectional view taken along the line V-V in Fig. 7A.
Figure 8A shows an embodiment of the invention in which the supply of the dilution liquid into the stock flow takes place in the turbulence generator after an intermedi-5 ate chamber, Figure 8B shows the construction of Fig. 8A viewed from above.
Figure 9 shows an embodiment of the construction in accordance with the invention in which the stock ducts and the dilution liquid ducts have been made into one single plate by machining. The plate extends across the entire width of the headbox.
As is shown in Fig. 1A, the headbox 10 of the paperboard machine comprises an inlet header J, after the inlet header J a system of pipes, i.e. a set of pipes 11 of the tube manifold, which produces turbulence in the stock flow, and after the set of pipes an intermediate chamber 12, which is opened into the stilling chamber 13.
After the intermediate chamber 12, there is a second set of pipes which produces turbulence in the stock flow, i. e. the turbulence generator G . The pipes G
1,1, G 1 .2 in the turbulence generator G are further opened into the slice cone 16, which comprises lamellae 17a1,17a2,17a3 in the way shown in the figure. The stock is passed further out of the slice cone 16 through an outflow gap onto the forming wire H. As is shown in the figure, the outflow opening after the slice cone 16 comprises a top slice bar n and a mechanism 18 for its regulation. The position of the top slice bar n can be regulated by means of the adjustment spindles 19 and adjustment motors 20 included in the regulation mechanism 18. The flow Ll of the dilution liquid is regulated by means of the valves V 1, V2. . . The equipment comprises a . number of distribution ducts D~,D2... for dilution flow across the width of the headbox, in which connection the desired dilution flows can be introduced into different locations of width across the headbox, and said flows can be regulated at each location of width by regulating the valve V 1, V2. . . of the dilution flow. As is shown in Fig. 1A, the dilution liquid, preferably dilution water, is passed into different locations of width across the headbox of the paper machine so that the dilution water is passed into the pipes llal,i,llal.2,11a1..~;Ila2.l,11a2.2,11a2,3;
lla3.l,lla3.~,11a3.3 ... in each vertical row in the tube manifold 11.
Fig. 1B illustrates the construction as shown in Fig. 1A viewed from above.
Fig. 1 C illustrates the system of valves V 1, V2, V3 . . . used in the regulation of the dilution liquid. The dilution liquid is passed from the dilution liquid inlet header J2 into the dilution liquid supply ducts D 1,D2. . . through the valves V ~ , V2.
. . By means of the valves, the flow of the dilution liquid L1 is regulated in each duct D1,D2...
independently from the other ducts.
Fig. 2 is a sectional view taken along the line I-I in Fig. 1B. As is shown in the figure, from the inlet header J 1 a stock flow L 1 is passed into each pipe 11 a 1.1, llal.2,l1a1.3;11a2.l,l1a2.2,11a2_3; lla3.i,l1a3,2,11a3.3 ... in the tube manifold 11.
The dilution liquid is passed as a dilution flow I2 into each pipe llat.l,llal.2, 11a1.3 in a vertical row in the tube manifold. The flow is passed through the distribution duct D1 or equivalent of the distribution pipe into the vertical row in the tube manifold 11 and further into each pipe 11 a 1.1,11 a 1,2,11 a 1.3 in each vertical row. Similarly, in the other different locations of width and vertical sections in the tube manifold, the dilution flow is passed out of the distribution ducts D2,D3... into the pipes lla2.i,l1a2.2,11a2,3;11a3.l,l1a3.2,11a3,3 ... in the vertical rows at corresponding locations in the tube manifold 11.
As is shown in Fig. 2, the distribution duct D1,D2 for dilution flow becomes narrower at its end so that the narrowing of the duct D 1 takes place towards the lowest pipe llal_3 in the tube manifold 11. As is illustrated in Fig. 2 by means of dashed lines, the duct portion Dla of the duct Di, which has been formed between the rows of pipes in the system of pipes, has additionally been formed so that its wall portion S 1 is placed as inclined in relation to the vertical plane. The branch ducts are opened from the wall S2 of the duct portion Dla into the pipes llal.i, 11a1.2... in the vertical rows in the set of pipes 11.
By means of said narrowing arrangement of ducts, the pressure can be kept invari-able in all the outlets E1.~,E1,2,E1.3 of fhe duct D1. As is shown in the figure, the cross-sectional shape of the distribution ducts E1.1,E1.2,Et.3 branched from the dilution flow duct D~ is rectangular.
Similarly, the cross-sectional shape of the end Dla of the duct D1 is rectangular, and said narrowing duct shape is produced by milling the end wall S1, which is placed inclined in relation to the vertical plane, in the end area of the duct D 1.
The duct D 1 portion Dla is connected with a resilient flexible duct portion Dlb, which comprises a regulation valve V 1 at its end. The dilution liquid is passed into the duct D 1 out of the dilution liquid inlet header J2.
The outlets of the branch ducts E1.1,E1.2~E1.3 into the pipes llal.l,llal.2,l1a1.3 in the tube manifold 11 are placed at the forward side of the throttle 21a1,~,21a1.2, 21a1,3 in relation to the flow direction L1. The throttle 21a1.1,21a1.2,21a1,3 is a conical contraction of the duct, which terminates in a straight duct portion 22a1.1, 22a1.2,22a~.3 (FIG. 4D). The most usual embodiment is a construction in which there is one single plate into which the pipes llal,l,llal,2,l1a1,3...;
lla2.l,11a2.2, l 1a2.3... formed into said plate of the tube manifold 11 have been made by drilling, the branch ducts E1.1,E1.2~E1.3 having been made into the front face T' of said plate by machining.
The pipes llal.l,llal.2,l1a1.3...; 11a2.1,11a2,2, 11a2,3... in the tube manifold 11 consist of two portions of sets of pipes, i.e. of pipes that have been machined, preferably drilled, into a separate plate and of separate pipe components connected with said pipes.
Fig. 3 illustrates the modular structural components M1 and M2 in the mixing part of the tube manifold 11. ' The structural components or modules M ~ , M2. . .
are preferably metallic plates T, into which the pipes llal.l,llal_2,1ia1.3 in the initial part of the tube manifold 11 have been made by drilling into the plate T. As each module M t ,M2 has been made as a separate structural component, the ducts D
1, D2. . . can be made into it, onto the front faces T' of the modules M 1, M2. .
. , easily by milling. Similarly, the duct D1,D2 shape narrowing towards the end in the end portions Dla,D2a... of the ducts can be accomplished by making the end wall S1 of the duct D1,D2..., whose cross-sectional shape is otherwise rectangular, inclined in the area of the end portion Dla,D2a... Similarly, the branch ducts E1_1,E1.2~E1.3~~~e E2.1 ~E2.2~E2.3~ ~ ~ ~ E3.1 ~E3.2~E3.3 ~ ~ ~ can be made easily by milling into the front wall T' of the plate T of each module M 1,M2. . .
In the embodiment shown in the figure, the ducts E1.1,E1.2~E1.3 are placed perpen-dicularly to the central axes X1_1,X1.2~X1.3 of the pipes llal.l,llal_2,11a1,3 in the tube manifold. In such a case the flows Ll and L2 meet each other at a right angle.
Fig. 4A shows the module M1 viewed in the direction of the arrow K2 in Fig. 3.
Fig. 4B is a sectional view taken along the line II-II in Fig. 4A.
Fig. 4C is a sectional view taken along the line III-III in Fig. 4A.
The illustrations in Figs. 4B and 4C do not show the throttle plate 20, but the fitting of said plate in connection with the construction is illustrated in Fig. 4D.
Fig. 4D shows the throttle plate 20 in connection with the front part, i.e.
the plate T, in the tube manifold 11. At the outlet side of the throttle plate 20, the separate pipes in the final part of the tube manifold 11 are placed, as is shown in Fig. 2.
Fig. 5 shows a second embodiment of the invention, which is in the other respects similar to the sectional view in Fig. 4C, except that in said embodiment the branch ducts E1.1,E1.Z~E1.3 have been milled into the construction so that the flow direction of the flow L1 out of the duct D1 can be directed so that it is oblique against the flow L2 coming from the inlet header J1. In such a case the mixing of the dilution flow L~ and the stock flow L2 can be made efficient.
The embodiment of Fig. 5 is mainly similar to the sectional view in Fig. 4C.
Fig. 6A shows an embodiment of the invention in which the duct portions Dla, D2a... of the ducts D1,D2... have been formed into a construction plate 50, which is placed alongside the throttle plate 20 and so that the narrowing duct portion Dla, D2a... is fitted to be opened so from the front face T" of the plate 50 that the cleaning of the duct system Dla,D2a... can be carried out by detaching a separate plate 60, which contains the initial part of the system of flow ducts (llal.l,l 1a1.2...;
11 a2.1,11 a2.2 . . . ; G 1.1 ~ G 1.2 ~ ~ ~ ~ G2.1 ~ G2.2 ~ ~ ~ ) intended for the flow L2 coming from the inlet header J1. Thus, when the plate 60 is detached, the narrowing ducts Dla~D2a~ ~ ~ and the connected branch ducts El.1,E1.2~ ~ ~ are opened for cleaning, and the extension portion Dlb,D2b... connected with the narrowing duct Dla,D2a...
does not interfere with the washing of the system of ducts, but said washing can be carried out by detaching the plate 60.
Fig. 6B is a sectional view taken along the line IV-IV in Fig. 6A.
Fig. 7A illustrates a plate-like module M1,M2 in accordance with the invention. The illustration in Fig. 7A is taken mainly in the direction of the arrow K2 in Fig. 3. The embodiment of Fig. 7A differs from that of Fig. 3 mainly in the respect that one side wall of the adjacent modular structural components, i.e. of the modules M1,M2, is defined by the duct D1,D2... What is shown is an embodiment in which one wall S4 of the conical portion DIa,D2a... of the duct D1,D2... is formed by one side wall F1 of the module M2 adjacent to said module M1. The initial part of the tube manifold 11 has been formed out of plate-like modules Ml,M2,M3... by intercon-necting said modules M1,M2,M3... in the direction of width of the headbox of the paperboard machine.
Fig. 7B is a sectional view taken along the line V-V in Fig. 7A.
Fig. 8A shows an embodiment of the invention in which the mixing of the dilution liquid and the stock flow takes place after the intermediate chamber 12 in the turbulence generator G at the forward end of its pipes G1.1,G1.2'G1.3~ ~ ~ ~
G2.1'G2.2' G2.3... in a way similar to the solution described above.
Fig. 8B shows the construction of Fig. 8A viewed from above in the area of the 5 forward end of the turbulence generator G.
Fig. 9 is an illustration in part of an embodiment of the invention which comprises narrowing ducts D 1,D2. . . for dilution liquid in connection with a tube manifold 11 composed of a single plate-like structural component T. The pipes in the tube 10 manifold 11 can have been made into a metallic plate construction conventionally by machining, preferably drilling. The ducts D1,D2... that supply dilution liquid have been made into the front face of the plate construction T, as was the case in the embodiments described above, by milling or by means of some other method of machining. The plate T extends across the entire width of the headbox. The con-struction can also be used in connection with the turbulence generator, after the intermediate chamber, or it can be used in a headbox construction which comprises, after the inlet header J1, just one system of pipes that produces turbulence and, after that, the slice cone.
Claims (23)
1. In an arrangement for combining a flow of dilution liquid with a flow of stock from an inlet header of a headbox of a paper/board machine, the arrangement including conduit means for passing the stock flow from the inlet header and dilution flow ducts through which the dilution liquid is passed, said conduit means comprising a plurality of conduits extending across a width of the headbox, the improvement comprising:
at least one of said dilution flow ducts being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by said walls at said upstream end being greater than a cross-sectional area defined by said walls at said downstream end, each of said dilution flow ducts being in flow communication with at least two of said conduits at one of a plurality of discrete locations across the width of the headbox such that the basis weight of a paper/board web formed upon discharge from the headbox is regulatable, and at least two branch ducts in flow communication with said narrowing duct portion of each of said at least one dilution flow duct, each of said branch ducts leading to a respective one of said at least two conduits.
at least one of said dilution flow ducts being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by said walls at said upstream end being greater than a cross-sectional area defined by said walls at said downstream end, each of said dilution flow ducts being in flow communication with at least two of said conduits at one of a plurality of discrete locations across the width of the headbox such that the basis weight of a paper/board web formed upon discharge from the headbox is regulatable, and at least two branch ducts in flow communication with said narrowing duct portion of each of said at least one dilution flow duct, each of said branch ducts leading to a respective one of said at least two conduits.
2. The arrangement of claim 1, wherein said narrowing duct portion of said at least one dilution flow duct is conical, all of said branch ducts in flow communication with each of said at least one dilution flow duct leading to one of said conduits in a respective vertical column of said conduits at a specific one of the locations across the width of the headbox.
3. The arrangement of claim 1 or 2, wherein said conduit means comprise a tube manifold comprising aligned vertical columns and horizontal rows of conduits, each of said at least one dilution flow duct being associated with a respective one of said vertical columns of said conduits, said branch ducts in flow communication with each of said at least one dilution flow duct being associated with a respective one of said conduits in said respective vertical column.
4. The arrangement of claim 3, wherein each of said conduits includes at least one step for producing turbulence, said at least one step being arranged after said branch duct in the flow direction of stock through said conduits, said at least one step constituting means for providing a change in the cross-sectional flow area of stock through said conduits.
5. The arrangement of any one of claims 1 to 4, wherein a first one of said walls defining said narrowing duct portion of said at least one dilution flow duct is inclined in relation to a vertical plane, an opening being defined in a second one of said walls adjacent to said first wall for each of said branch ducts in flow communication with said at least one dilution flow duct.
6. The arrangement of any one of claims 1 to 5, further comprising a plate having a front face, at least said narrowing duct portion of said at least one dilution flow duct being formed in said front face of said plate, said conduits being machined into said plate.
7. The arrangement of claim 6, wherein said branch ducts are machined into said front face of said plate.
8. The arrangement of any one of claims 1 to 7, further comprising a throttle plate having a plurality of throttle holes each including a conical narrowing section, said throttle plate being arranged in relation to said conduits such that one of said throttle holes in said throttle plate is aligned with each of said conduits.
9. The arrangement of claim 8, wherein said throttle plate is arranged in relation to said branch ducts such that a forward edge of said throttle holes adjoins a rear edge of said branch ducts.
10. The arrangement of claim 8, wherein said throttle holes in said throttle plate further comprising a straight flow duct section arranged after said conical narrowing section in the flow direction, said throttle plate being arranged adjacent said front face of said plate.
11. The arrangement of any one of claims 1 to 10, wherein each of said at least one dilution flow duct further comprises a flexible hose in flow communication with said narrowing duct portion.
12. The arrangement of any one of claims 1 to 11, wherein said conduit means comprise a plurality of interconnected modules extending in the direction of width of the headbox, each of said modules comprising at least one of said conduits and a peripheral wall constituting one of said walls of an adjacent module.
13. The arrangement of any one of claims 1 to 12, wherein said conduit means comprise a tube manifold arranged to receiving the stock flow directly from the inlet header.
14. The arrangement of any one of claims 1 to 13, wherein said conduit means comprise a turbulence generator arranged to receiving the stock flow indirectly from the inlet header, the stock flow passing through an intermediate chamber between the inlet header and said turbulence generator.
15. The arrangement of any one of claims 1 to 14, wherein said branch ducts are arranged to direct the dilution liquid from an outlet of said branch ducts at an oblique angle in relation to a central axes of said conduits and against the stock flow in said conduits.
16. The arrangement of any one of claims 1 to 15, wherein said narrowing duct portion of said at least one dilution flow duct is formed so that one of said walls of said narrowing duct portion is inclined in relation to the vertical plane.
17. The arrangement of any one of claims 1 to 16, further comprising first, second and third plates, said narrowing duct portion of said at least one dilution flow duct being formed between a wall of said first plate and a recess in a first face of said second plate and said branch ducts being formed in said first face of said second plate, said conduits being formed in said second plate, said second plate being separable from said first plate to enable access to said at least one dilution flow duct and said branch ducts, said third plate constituting a throttle plate having a plurality of throttle holes and being arranged in relation to a second face of said second plate opposed to said first face such that one of said throttle holes in said throttle plate is aligned with each of said conduits.
18. A method for combining a flow of dilution liquid with a flow of stock from an inlet header of a headbox of a paperboard machine at a location between the inlet header and a slice chamber of the headbox, comprising the steps of:
passing the stock flow from the inlet header through conduit means comprising a plurality of conduits extending across a width of the headbox, passing dilution liquid through a plurality of dilution flow ducts each in flow communication with at least two of said conduits situated at a discrete position along the width of the headbox, each of said dilution flow ducts being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by said walls at said upstream end being greater than a cross-sectional area defined by said walls at said downstream end, and passing the dilution liquid from each of said dilution flow ducts through at least two branch ducts in flow communication with said narrowing duct portion of said dilution flow duct and into a respective one of said at least two conduits.
passing the stock flow from the inlet header through conduit means comprising a plurality of conduits extending across a width of the headbox, passing dilution liquid through a plurality of dilution flow ducts each in flow communication with at least two of said conduits situated at a discrete position along the width of the headbox, each of said dilution flow ducts being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by said walls at said upstream end being greater than a cross-sectional area defined by said walls at said downstream end, and passing the dilution liquid from each of said dilution flow ducts through at least two branch ducts in flow communication with said narrowing duct portion of said dilution flow duct and into a respective one of said at least two conduits.
19. The method of claim 18, further comprising the step of:
passing the stock flow from the inlet header directly into said conduit means arranged directly adjacent the inlet header.
passing the stock flow from the inlet header directly into said conduit means arranged directly adjacent the inlet header.
20. The method of claim 18 or 19, further comprising the steps of:
passing the stock flow from the inlet header directly into a tube manifold, passing the stock flow from the tube manifold into and through an equalizing chamber, and passing the stock flow from the equalizing chamber into said conduit means.
passing the stock flow from the inlet header directly into a tube manifold, passing the stock flow from the tube manifold into and through an equalizing chamber, and passing the stock flow from the equalizing chamber into said conduit means.
21. A method for regulating the basis weight of a web upon its discharge from a headbox of a paper/board machine, comprising the steps of:
passing a stock flow from an inlet header of the headbox through conduit means comprising a plurality of conduits extending across a width of the headbox, introducing dilution liquid into the stock flow in at least one of said conduits by passing the dilution liquid through at least one of a plurality of dilution flow ducts each leading to at least two of said conduits situated at a discrete position along the width of the headbox, said at least one dilution flow duct being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by said walls at said upstream end being greater than a cross-sectional area defined by said walls at said downstream end, and passing the dilution liquid from said at least one dilution flow duct through at least two branch ducts in flow communication with said narrowing duct portion of said at least one dilution flow duct and into one of said conduits, regulating the flow of the dilution liquid through said dilution flow ducts to thereby regulate the basis weight of the web, and discharging the stock flow including the dilution liquid from the headbox to form the web.
passing a stock flow from an inlet header of the headbox through conduit means comprising a plurality of conduits extending across a width of the headbox, introducing dilution liquid into the stock flow in at least one of said conduits by passing the dilution liquid through at least one of a plurality of dilution flow ducts each leading to at least two of said conduits situated at a discrete position along the width of the headbox, said at least one dilution flow duct being defined by walls and including a narrowing duct portion having an upstream end and a downstream end, a cross-sectional area defined by said walls at said upstream end being greater than a cross-sectional area defined by said walls at said downstream end, and passing the dilution liquid from said at least one dilution flow duct through at least two branch ducts in flow communication with said narrowing duct portion of said at least one dilution flow duct and into one of said conduits, regulating the flow of the dilution liquid through said dilution flow ducts to thereby regulate the basis weight of the web, and discharging the stock flow including the dilution liquid from the headbox to form the web.
22. The method of claim 21, further comprising the step of:
passing the stock flow from the inlet header directly into said conduit means arranged directly adjacent the inlet header.
passing the stock flow from the inlet header directly into said conduit means arranged directly adjacent the inlet header.
23. The method of claim 21, further comprising the steps of:
passing the stock flow from the inlet header directly into a tube manifold, passing the stock flow from the tube manifold into and through an equalizing chamber, and passing the stock flow from the equalizing chamber into said conduit means.
passing the stock flow from the inlet header directly into a tube manifold, passing the stock flow from the tube manifold into and through an equalizing chamber, and passing the stock flow from the equalizing chamber into said conduit means.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI962567A FI98938C (en) | 1996-06-20 | 1996-06-20 | Apparatus for combining the dilution flow with the pulp flow from the paper / board divider |
| FI962567 | 1996-06-20 | ||
| PCT/FI1997/000386 WO1997048851A1 (en) | 1996-06-20 | 1997-06-18 | Equipment for combining a dilution flow with the stock flow passed out of the inlet header in a paper/board machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2258232A1 CA2258232A1 (en) | 1997-12-24 |
| CA2258232C true CA2258232C (en) | 2007-01-02 |
Family
ID=37603670
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002258232A Expired - Fee Related CA2258232C (en) | 1996-06-20 | 1997-06-18 | Equipment for combining a dilution flow with the stock flow passed out of the inlet header in a paper/board machine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2258232C (en) |
-
1997
- 1997-06-18 CA CA002258232A patent/CA2258232C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2258232A1 (en) | 1997-12-24 |
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