US3382143A - Paper forming assembly and method - Google Patents

Paper forming assembly and method Download PDF

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Publication number
US3382143A
US3382143A US467664A US46766465A US3382143A US 3382143 A US3382143 A US 3382143A US 467664 A US467664 A US 467664A US 46766465 A US46766465 A US 46766465A US 3382143 A US3382143 A US 3382143A
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stock
wire
indicated
cross
velocity
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US467664A
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Edgar J Justus
David R Gustafson
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Beloit Corp
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Beloit Corp
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Priority to US467664A priority Critical patent/US3382143A/en
Priority to DE19661511229 priority patent/DE1511229A1/de
Priority to BE683061D priority patent/BE683061A/xx
Priority to LU51407A priority patent/LU51407A1/xx
Priority to NL6608977A priority patent/NL6608977A/xx
Priority to ES0328517A priority patent/ES328517A2/es
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    • 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
    • D21F9/00—Complete machines for making continuous webs of paper
    • D21F9/003—Complete machines for making continuous webs of paper of the twin-wire type
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J1/00—Fibreboard

Definitions

  • the present invention relates to a plural wire web forming device wherein a web forming zone is defined between converging forming wires by the use of curved, stationary, permeable guide means acting against one wire to urge such wire through an elongated substantially curved path and into convergence with the opposite wire under tension.
  • the present invention relates to improvements in paper making machinery or the like, and more particularly, in improvements in devices and methods for forming the initial web of fibrous material from a dilute liquid suspension in paper machines or the like.
  • the instant invention is particularly adapted for use in the forming arrangement of paper making machinery and it will be described primarily in connection therewith, it will be appreciated that the invention has other uses in related devices.
  • the instant invention is concerned with a new and unique forming arrangement which "has been devised by us for such purposes as accommodating higher paper making machinery speeds as well as improved quality in the paper so made. It will be appreciated that the very substantial capital investment in paper making machinery makes it necessary for continuous research and development in improvements in not only paper making quality but operating speeds for such machinery.
  • the instant invention provides a novel arrangement and method for effecting improved paper making quality at high speeds.
  • FIGURES 1A, 1B and 1C are elevational views shown in the sequence ABC of a paper machine forming section embodying the instant invention and it will be appreciated that these three views may be referred to as a single embodiment of a forming unit;
  • FIGURE 2 is a fragmentary enlarged detail view of an upper foil suction box taken generally along the line 11-- II of FIGURE 1B, with parts broken away or not shown for purposes of simplification;
  • FIGURE 3 is a side elevational view taken generally along the side indicated at III-III of FIGURE 2 showing in side elevation generally the specific aspects of the foil suction box employed in the practice of the instant invention;
  • FIGURE 4 is an elevational view, with parts broken away and parts shown in section of an inlet or headbox for use in the practice of the invention
  • FIGURE 5 is an essentially diagrammatic fragmentary cross-machine section, with parts broken away and parts shown in section, taken generally along the line of the roof of the inlet of FIGURE 4, such line being indicated at V-V;
  • FIGURE 6 is an essentially schematic view shownin elevation to correspond to the elevational view of the inlet indicated in FIGURE 4, but again with certain parts broken away, and the view of FIGURE 6 is intended to represent generally the variations in cross sectional area of the controlled thin portions of the stock inlet;
  • FIGURE 7 is a fragmentary detail enlarged view of certain essential elements in the central portion of the narrow stock inlet of FIGURE 4, taken approximately from the same view as that shown in FIGURE 4, but showing these essential elements in enlarged elevation and section;
  • FIGURE 8 is an essentially diagrammatic top plan view of a cross-flow header for stock for the inlet of the embodiment of the instant invention.
  • FIGURE 9 is an essentially diagrammatic elevational view showing the overall inlet assembly of the instant invention taken generally from the rear side of the inlet.
  • FIGURE 10 is an essentially diagrammatic view comparable to that of FIGURE 9 but showing still another embodiment of the instant invention.
  • the reference numeral 10 indicates generally a high speed stock inlet which consists essentially in means for generating and feeding a thin generally horizontal high speed stock jet of substantially homogeneous suspended entangled co-moving stock fibers on to a bottom wire reach here indicated at 20, of a forming wire that is trained around an initial turning and drive roll 21, a breast roll 22, and a couch roll shown at 23 in FIGURE 1C, each of which rolls 21, 22 and 23 being mounted on appropriate bearings which in turn are mounted on conventional framing indicated generally at 24 in the views of FIGURES 1A, B and C, but without showing specific details of the bearing mountings for the various rolls mentioned, since such aspects of mounting forming wire 20 and supporting rolls are old and well known in the art.
  • the forming wire passes from the breast roll 22 to the couch roll 23 over a plurality of suction boxes SB-l through SB-S which are of well known structure and which function to exert a subatmospheric pressure to the underside of the forming wire 20 while the stock and/or web is moving on the forming wire 20 for purposes of dewatering the same in a function that is old and well known to the skilled workers in the art.
  • the framing support for such suction boxes SB1 through 5 is indicated in part at 24a and 24b in FIGURES 1B and 1C, for purposes of showing the general arrangement, although specific details thereof are also fully understood by the skilled workers in the art.
  • the framing support for the initial suction box SB-1 shown in FIGURE 1B carries a cross-machine frame 24c which mounts a foil 25 that engages the underside of the forming wire 20 for relative movement therebetween, the foil 25 being maintained stationary, but for purposes of supporting the underside of the forming wire 20 and at the same time assisting in the removal of droplets of water tending to collect on the underside of the forming wire 20 in the region of the immediate off-running side of the upper foil box, indicated at 30 and shown in greater detail in FIGURES 2 and 3.
  • the structure of the foil 25 is well known to those skilled in the art and is provided with a rounded forward edge 25a for initial engagement with the underside of the wire 20 followed by a generally flat or planar surface which gradually separates from the underside of the wire 20 through a relatively small angle of about 5 for purposes of generating a pumping effect to assist in water removal.
  • This particular function of the foil 25 is old and well known at the present time in paper making machinery. It will be noted,
  • the foil 25 is mounted on shims or other suitable devices to afford vertical adjustment therefor indicated diagrammatically by the two-headed arrow at A in the support pedestal 240 of FIGURE 1B.
  • the relative vertical adjustment of the foil 25 is also carried out by structures understood by the skilled workers in the art, and is therefore indicated diagrammatically by the twoheaded arrow A, although it will be appreciated that such relative vertical adjustment of the foil 25 has certain functions in the practice of the instant invention which will be described in greater detail hereinafter.
  • FIGURE 1B there is shown fragmentarily a wire tensioning roll 26 with adjustable means indicated also by a double headed arrow designated A for purposes of adjusting the overall tension on the forming wire 20, as it is used in the practice of the instant invention.
  • the relative position of the wire reach 20a between the top of the breast roll 22 and the top of the foil 25 is controlled not only by the adjustable positioning of the foil 25 but also the adjustable tensioning on the wire 20 by the tension roll 26, both of which adjustable devices are understood by the skilled workers in the art and need not be described in further detail herein.
  • the breast roll 22 itself may be mounted adjustably (as indicated schematically by the double headed horizontal and vertical arrows AA at the bearing B) for additional facility in adjusting the overall position of the wire reach 20a which moves generally in the longitudinal direction or in the direction of stock and web movement.
  • the device for generating the previously described thin stream of the high speed stock jet is indicated essentially diagrammatically at 10 with an internal passage of crossmachine width being shown diagrammatically at 10:: for purposes of indicating the location of the stock stream jet being generated.
  • the overall stock inlet 10 is mounted on suitable bottom framing indicated at 11 plus upright framing indicated at 12 and 13 for carrying the horizontal slice jet generating and defining means indicated at 14a and 14b, feeding stock from a suitable source indicated at 15 into which stock is fed at a controlled rate by a suitable stock flow device such as a fan pump indicated diagrammatically at F in FIG- URE 1A at a rate sufficient to generate the desired speed and other properties in the stock jet flowing in predetermined manner out of the stock jet opening indicated at 14 in FIGURE 13.
  • a suitable stock flow device such as a fan pump indicated diagrammatically at F in FIG- URE 1A
  • the stock jet generating device 10 herein indicated in essentially diagrammatic form is known to prior workers in the art and well understood thereby and need not be described in further detail, except to mention various patent disclosures hereinafter which describe suitable means for stock jet generation useful in the practice of the instant invention. It Will be noted, however, that the overall stock jet generating device 10 here shown is indicated diagrammatically as generating a substantially horizontal stock jet stream at the slice outlet 14 of FIGURE 1B at substantially the top of the breast roll 22.
  • each of these various disclosures and a number of other prior art disclosures have shown various turbulence generating devices which, in the present diagrammatic showing would be located in the section indicated at 14a or upstream thereof and would be used essentially for initially effecting a complete distribution of discrete individual fibers in the dilute stock being generated for high speed feed through the continuous channel 10a here shown diagrammatically extending through the sections 14a and 14b of FIGURE 1A.
  • the essence of the stock jet or stock stream generating channel or device 10 involves the creation of an initial turbulence of one type or another upstream in the region of the channel 10:!
  • the thin stream is of only approximately from inch to 1 /2 inch in height, depending on basis weight and grade of paper, in the region of the slice 14' as it is fed from the channel 10/) at an extremely high velocity (in the neighborhood of 2500 to 3000 or more feet per minute) at the requisite high pressures and in the generally horizontal or longitudinal direction aligned with the direction of an imaginary reference (abscissa) line, which is indicated at the line 200 in FIGURE 3 hereof.
  • the line 200 is an imaginary straight line drawn in a tangent plane generally from the top of the breast roll 22 at substantially the slice exit 14- and extending to the top of the foil 25. Since the wire 20 is not without some elasticity and flexibility, no matter how much tension is placed on the wire by the roll 26 or otherwise, it will be appreciated that the wire 20 will have a tendency to be forced downwardly slightly below this imaginary line 200 by the force of the stock on the top thereof, but one of the important objects of the instant invention involves maintenance of the forming wire 20 at a relatively high tension by the use of the tensioning roll 26 or other conventional devices so that the bottom reach 20a of the forming wire between the breast roll 22 and the foil 25 is here shown being maintained substantially planar, i.e., the line 20a appears to be substantially a straight line as indicated in FIGURE 1B and thus to align substantially with the imaginary straight line 200 of FIG- URE 3 by virtue of the maintenance of the high tension therein.
  • the device 10 provides the stock feed conduit 10a and associated operating elements (all understood by the skilled workers in the art) for generating and feeding a thin high speed stock jet (at approximately 14) of substantially homogeneous suspended entangled co-moving stock fibers in dilute aqueous system, which stock jet is fed on to the Wire reach 20a at approximately the top of the breast roll 22 and the stock jet is substantially commensurate in transverse dimension and longitudinal speed to that of the wire reach 20a at the immediate vicinity (14) at which the stock jet is fed on to the wire reach 20a and the stock jet is aligned and fed on to the wire reach 20a in substantially the same generally horizontal direction of the movement of the initial Wire reach 20a.
  • the high speed stock jet at 14 flows on to the top of the forming wire 20 at substantially the top of the breast roll 22 or at least plus or minus about 10 or from the vertical center line 22CL for the breast roll 22 supporting from beneath the forming wire 20.
  • an upper forming wire which is indicated generally by the reference numeral 40.
  • the upper forming wire 40 travels beneath and is supported on the top side by the foil box 30 in the approximate region of the jet outlet 10b (as indicated in FIGURE 1B), and it also travels around appropriate guide and tensioning rolls indicated at 41, 42, 43, 44, 45 and 46.
  • the horizontal framing 24 is also provided with upright frame elements 24d, 24a and 24 with the last-mentioned upright 24 supporting the guide roll 46 for rotation and separation of the forming wire 40 from the formed web W which is carried away on the lower forming wire 20, as shown in FIGURE 1C.
  • the upright support 24f is also the principal support for a couch press defined by the plain bottom couch roll 23 supporting from beneath the forming wire with the web W thereon and an upper couch press roll 47 within the loop of the upper wire 40 which is carried at opposite ends on fixed 47a and movable 47b pivots, with the movable pivots 4719 being in turn attached to a suitable power cylinder 47c that is in turn connected to a lower extension of the framing at 241i for purposes of controlling the load at the couch nip N, which is the nip defined between the forming wires 20 and 40 and plain press rolls 23 and 47 for purposes of removing excess water at the location of the nip N by mechanical means, prior to subsequent treatment of the web W as it is fed into the rest of the machine on the forming wire 20.
  • the advantages of a couch press 23-47 are apparent to the skilled worker in the art; but the successful use of the same heretofore has been limited, if possible at all, for the reason that it is necessary to have a reasonably strong web formation prior to the application of any pressing action for dewatering thereof and Webs of this strength were heretofore ordinarily not possible at such an early stage in the forming operation (or so closely spaced from the stock jet slice 10b) as here indicated.
  • the initial forming arrangement including particularly the top foil suction box 30 is so constructed as to afford a maximum rate of dewatering and a maximum rate of strong web formation making possible the use of the couch press 2347 here shown.
  • the upright frames 24d and 2% are provided with appropriate cross frames 2412 and 24g, all of conventional structure which the skilled worker in the art will understand are positioned (as in the case of all of the framing here indicated) at opposite sides of the forming wires 20 and 40 so as to mount opposite ends of the functioning devices herein described.
  • a bearing pedestal 242a is indicated as being mounted on the upright 24:: for the purpose of mounting the wire guide roll 45.
  • a bearing pedestal 24dd is shown as an extension of the upright 24d for mounting the guide roll 42; and a bearing pedestal 24xx is shown mounted on the side of the upright 24d for mounting the guide roll 41.
  • the specific lower portion of the foil suction box is actually mounted in a housing 31 which is pivotally mounted at its forward end on the previously described pedestal 2 4xx and is adjustable in a generally vertical direction by the use of a jackscrew indicated at 18-3; whereas the rear end of the housing 3'1 is mounted on a depending frame 241th carrying a jac'kscrew JS-4 which is adapted for limited vertical adjust-ment or movement as indicated by the double headed arrow A.
  • the jackscrews JS3 and JS'4 thus provide conventional controlled means of adjustment for effecting overall vertical movement as well as relative tilting of the housing 31 and the lower functional portion of the foil suction box 30 which actually contacts the inside of the loop of the forming wire 40.
  • a side suction takeoff 33 is provided at the rear end of the housing 31 (although indicated essentially diagrammatically) with an appropriate overflow dam indicated at 35 within the housing 31, so that water drawn up through the foil suction box 30 will fall over the dam 35 and be withdrawn from the side of the machine through the suction takeoff 33 in substantially the manner of operation employed for water and air removal through suction box takeofis which are, of course, employed in connection with the suction boxes SB-l through "5 hereinbefore described.
  • the dam 35 will, of course, tend to control to some extent the water level continuously accumulating in the lower portion of the upper suction box housing 3 1, whereas the top side of the housing 3 1 is closed and maintained at subatmospheric pressure by virtue of the suction takoff 33.
  • the forming wire travels downwardly around the guide roll 41 and then around a curvate solid surface or shoe indicated generally at which aligns the same for its travel in guided fashion along the bottom of the longitudinally spaced crossmachine foils in the foil box 30 indicated at 51 through 60.
  • the individual longitudinally spaced cross-machine foils 51 through are shown in an elevational view in FIGURE 3 (through the side wall 30a of the bottom foil box 30 and fragment'arily in a top elevation in FIGURE 2); and, in contrast to the previously described foil 25, the structures of the foils or blades 51, 52, etc. are different, and these foils 5'1, 52, etc. have individual structures such as those shown substantially in Van Ryzin US. Patent No.
  • FIGURE 2 a deckle or sealing piece 3% is shown in FIGURE 2 as being attached to the side wall 30a and is shown in FIGURE 3 as extending along the bottom of the side Wall 30a and having a general-curvate bottom surface which is more pronounced at the forward or left hand end 3012b thereof.
  • top plan view only the portion indicated at 30b being visible at the forward end and the top plan portion 30b" being visible at the rear or right hand end of the sealing piece 3% in FIGURE 2, with the remainder thereof being shown covered at least in part by the various slanted foils d through 60.
  • the foils 5 through 60 extend downwardly from the top exposed thin edge portions 51x through 60x shown in FIGURE 2 down to thin edge bottom portions 51b through 60']; each of which engages and is secured to the top of the side sealing strip 30b indicated in FIGURES 2 and 3.
  • each of the individual foils 51 through 60 extending downwardly beneath the sealing edge 30b (which is shown on one side only in FIGURE 2, but which will be under stood to be present at opposite sides of the foil box 30 in a complete view) extends downwardly to engage the top side of the traveling wire 40 along a smoothly machined (i.e. mirror finished) guiding surface or edge 51a through 60a indicated for the bottom of each of the foils 51 through 60.
  • the top edge 52x is shown and this foil 52 then extends from the top edge 52 downwardly and to the left to a surface 521; along the edge thereof which engages the sealing strip 3% and to a surface which is indicated farther to the left in FIGURE 2 at 52a which engages the inside of the loop at the top wire 40 and controls the position thereof.
  • the extreme bottoms of the foils 51 through 60, at the polished i.e. preferably to a mirror finish, per Walker Ser. No. 150,917, filed Nov.
  • the foil box 30 is framed by conventional removal seals, i.e., a sealing rear piece 31a, with an appropriate flange 31b to afford means for securing it to the foil box 30 (as indicated in F IGURES 2 and 3); whereas FIGURE 1B shows a front rounded crossmachine sealing piece 50 with seal shim 31c that is secured to the forward or left end of the foil box 30 (FIG- URES 2 and 3); and a machine-side sealing piece 31c (counterpart of a drive side piece not shown) is seen partially in FIGURES 1B and 2 (although these are essentially omitted from other views for purposes of simplicity) to complete the peripheral seal for the foil box 30.
  • a sealing rear piece 31a with an appropriate flange 31b to afford means for securing it to the foil box 30 (as indicated in F IGURES 2 and 3)
  • FIGURE 1B shows a front rounded crossmachine sealing piece 50 with seal shim 31c that is secured to the forward or left end of the foil box 30 (
  • the forward shim sealing piece 31c has a lower smooth bearing surface 310 (abruptly terminating at its off-running edge line 30bb) that forms a continuation for the initial guide surface for the wire, previously indicated at 50 in FIGURE 1B, and this overall surface 50, 31c is preferably generally cylindrical in contour (and abruptly terminating at 301112) for smooth movement of the wire thereover and feeding of the wire 40 in smooth uninterrupted manner directly on to and over the spaced smooth bottom guide surfaces of the stationary foil edges 51a through 60a which also terminate abruptly at the off-running sides thereof (as contrasted to gradual divergence as described for the foil in order to separate abruptly from the traveling wire 40 so as to preclude localized pumping effect pressure variations drastic enough to damage web formation on the wire 40.
  • the significant feature of the overall bottom contour arrangement of the foil box 30 involves specifically a reference to an elongated curve that is based generally upon a theoretical abscissa lying along the imaginary line 2% hereinbefore described in which the increment thereof will be indicated by the reference letter D shown with a two-headed arrow in FIGURE 3; and an ordinate indicated generally by the center line CL in FIGURE 3 in which the increments thereof will be indicated by the reference letter H also indicated by a two-headed arrow in FIGURE 3.
  • the intersection of the abscissa 200 and the ordinate CL is the theoretical 0, 0 for the curve:
  • H is the distance (in inches) vertically up from the line 200
  • D is the distance (in inches) to the right indicated at D through D of FIGURE 3, or in the positive direction from the line CL, as shown in FIGURE 3
  • C and k are constants.
  • top wire is there shown in a position where it is fully supported from above by the smooth surfaces and 31c which feed the same to a point P (FIGURE 3) on the ordinate CL; and prior to the point P to the backing surfaces 50 and 310 make the wire 40 impervious or Water impermeable.
  • the leading foil edge 51a i.e., the next point P (and, of course, at the slightly higher point P the height H of the wire 40 above the abscissa 200 (shown in exact longitudinal alignment with the wire 20 on the breast roll 22 in the specific arrangement of FIGURE 3) is substantially the height of the stock jet stream issuing at 14' (assuming the wire run 20a is maintained in substantially the undeflected alignment and spacing shown in the standing arrangement of FIGURE 3), and flowing at approximately 3000 feet per minute for the present embodiment.
  • the wire 40 becomes functionally waterperrneable and initially receives water flowing into the foil box 30.
  • the solid supports 50 and 310 are positioned very closely to the top of the structure 14b for the stock jet inlet 14 (and the wire 40 runs there'between in very close running relation) such that substantially the full stock jet pressure will be exerted against both the top and bottom wires 40 and 20 substantially immediately after and/ or at the region P to P with negligible backward flow and/or loss of pressure by backward stock flow or upward flow back between the inlet structure 1412 and the solidly supported wire 40.
  • point P will be considered as lying in the ordinate CL and the distance from. P to P will be considered to be approximately one inch (actually inch). Roughly speaking, the curve including the loci P to P must be considered to be a generally elongated noncircular curvature in its transition from the generally cylindrical (or circular in section defined by the cylindrical solid guiding surfaces 50, 31c) to the elongated curved configuration defined by the longitudinal contour of the loci of the foil bottoms 51a, etc.
  • the essence of the curve of the loci of P to P will not necessarily be curvilinear even though for practical purposes it is inherently curved for aligning the wire 40 with the subsequent elongated generally curved contour of the wire alignment found to be substantially essential to the practice of the invention; and the stock jet stream 14 will be considered as having substantially the same structure in width, height, speed, etc. as that passing through the center line CL (even though it may not exit from its supporting structure 14b at precisely this point, and, is shown in FIGURE 1B, is obviously upstream therefrom).
  • the abscissa 200 will be considered as lying in a generally horizontal plane (substantially perpendicular to the aforesaid center line CL) and defining a straight line in substantial longitudinal alignment with the wire run 20a which may be deflected somewhat away from such horizontal plane.
  • the line 200 is horizontal.
  • the critical area in the operation of the forming area is the converging sheet forming zone immediately after the stock leaves the inlet 14b and is deposited on the bottom wire 20.
  • This zone is the converging nip where the top wire 40 approaches the bottom wire 24) and where the water is drained from the stock slurry both upward and downward, leaving the fiber deposited between the two wires 20 and 40 to form the sheet or ultimate web W.
  • the function of the top wire 40 in conjunction with the bottom wire 20, besides providing a spetum through which water can be drained from the sheet upward as well as downwardly, is to eliminate the free surface and thus provide stability and control over the slurry as it is being drained to form the sheet.
  • the tests made on experimental forming units have shown that the convergence of the forming nip is critical.
  • the nip is made by maintaining tension in the bottom wire 20 (or bottom portion 200) and having the top wire drag (also under tension) against the contoured bottom cover of the top forming box as indicated at the longitudinally spaced surfaces 51a, 52a, 53a, etc. (i.e., the longitudinal contour of the loci of such spaced wire-contacting surfaces of edges 51a, 52a, etc. with the driven wire 40 driven through the general longitudinal contour of a multiplicity of short successive short reaches bridging the short spaces between such edges 51a, 52a, etc. so as to travel substantially along the elongated curve defined by such loci).
  • the given formula for the curve is referenced primarily to the longitudinal contour of the active face or cover of the foil box 30 (and so are the ordinate CL and the abscissa 200 for purposes of defining such curve) although the foil box 30 itself is mounted for limited vertical and pivotal movement in the manner hereinbefore described.
  • the D axis is the theoretically straight line previously indicated at 200, i.e., extending from the top of the breast roll (bottom wire support roll just ahead of the open portion of the forming box) to the top of bottom wire support following the forming box and the H axis is the line perpendicular to the D axis, i.e. previously referred to as CL extending downward from the initial opening to the vacuum compartment in the suction box 30.
  • the machined surface of the forming cover now being used on a foil box 30 may be considered to be (the longitudinal contour of loci of the blade edges 51a, 52a, etc.) plotted on the graph previously indicated (in FIGURE 3).
  • the object in this critical region of stock formation is to keep substantially the same internal pressure (which is within the stock on both the top and bottom semiwebs).
  • the stock pressure as well as foil box alignment are compensated for by the type of dipping which the bottom wire 20a may tend to undergo in this region (below the theoretical line 200) which can and will be for this essential purpose.
  • the relative position of the top wire 40 is fairly well fixed by the bottoms of the closely spaced foils 51, 52, etc. which determine the longitudinal contour of loci that will define the elongated curve previously set forth.
  • the longitudinal (linear) speeds of the two wires 20 and 40 are substantially equated by known wire drive control means (e.g. inter-connected drive motors M and M for any suitable driving rolls such as the couch rolls 23 and 46, as schematically indicated in FIGURE 1C).
  • the object is to bring the wires together generally in conformance with the contour of the curve, and after the elongated curve the wires should be moved together, gradually, to effect water removal at increased pressure but without the necessity of extreme caution in effecting the increased pressure.
  • the network strength of the web is strong enough after the region of the elongated curve to resist damage at increasingly higher pressures and because there is no real network to damage or destroy before the region of the elongated curve (because of the substantial dilution of the stock).
  • the fiber network is commencing to build up on the top and bottom wires 40 and 20 over the distance from about D to substantially D to D and simultaneously the comparatively lower stock consistency (i.e. comparatively greater Water to fiber ratio) intermediate these sensitive fiber networks on the top 40 and bottom wires 20 are responsive to pressure change between the wires and it is important to maintain temporarily a substantially constant pressure on such network or overall system on each wire until there is a substantial equalization among the consistencies of such (with the more dilute stock being drained therethrough.
  • the minimization of drastic pressure variations along the wire 40 is effected by the abruptly terminating off-running sides of each of the wire guiding foil edges 51a, 52a, etc. plus the overall slanted configuration of the foils 51, 52, etc.
  • the stock consistency for newsprint (e.g. as much as 0.5% up to even 1.0%) is much greater than that of the so-called tissue (e.g. which is in the lower range of about 0.1% to about 0.5%, by weight).
  • tissue e.g. which is in the lower range of about 0.1% to about 0.5%, by weight.
  • the consistency is so low that the rate of build up of a web or septum on the wire is even less than (and certainly not more than) that which occurs in a machine having both top and bottom active wiressubject to vacuum, etc.
  • the elongated curved contour of the bottom wire on a tissue machine (of the type disclosed in the application of E. J. Justus, filed Jan. 18, 1965 may have many, if not all, of the advantages of the elongated curved top configuration of a top wire on the instant preferably high consistency, e.g. newsprint machine), which because of its lower consistency, not only tends preferably to conform to the desired elongated curve along the top wire but also drives the bottom wire into a conforming noncircular-type curve.
  • FIGURE 4 there is shown the essential concept of the preferred inlet in the combination of the invention from a side elevational view with parts shown in section, showing primarily certain fundamental features of the instant inlet designated generally by the reference numeral it). These include generally closely spaced, laterally or cross-machine extending top 11' and bottom 12' walls which converge from a relatively thin (i.e.
  • inlet 13' from which the walls 11' and 12 extend longitudinally from right to left in the direction of stock flow in the device 10" a substantial distance convergingly, in fact, so as to converge approximately at an angle of convergence of about 3, but which may range from a minimum practical angle of convergence of about 1 to a maximum practical angle of convergence of about 10, which angle of convergence is indicated in the schematic showing of FIGURE 6 as the angle B or as the total of the two halves indicated at B and B in FIGURE 6.
  • the top and bottom walls 11' and 12' extend the full width of the paper machine which may range from minimum commercial machine sizes in the neighborhood of 100 to 150 inches to as much as the maximum known commercial machine sizes which are now in the neighbrohood of about 340 or 350 inches.
  • transverse refers to the cross-machine direction whereas longitudinal refers to the so-called machine direction.
  • the stock flows through the inlet portion defined between the generally converging walls 11' and 12' in a generally longitudinal direction toward the slice 14', from which it flows (usually through a slight drop) onto a lower traveling forming surface 20 which is the usually very fine woven screen that is referred to in the paper machine trade as the forming wire.
  • the stock may thus be fed from the slice 14' onto the top of one forming wire 20* and between two converging forming Wires 20, 40, in the type of forming device to be used.
  • the stock (volume) velocity at the slice 14' being essentially the velocity of fibers as well as water at the slice, is essentially the velocity of the forming wires 20, 40 and thus, as previously indicated in a paper machine operating at 2,400 feet per minute the linear velocity of stock at the slice 14 will be approximately 40 feet per second.
  • the slice 14' has a definite but very thin dimension as well as its very substantial transverse dimension.
  • This thin dimension is generally perpendicular to the horizontal or to the lower forming wire 20 itself, with respect to the alignment of the dimension, which is indicated schematically in FIGURE 6 as the dimension A
  • the dimension A is in effect the cross-sectional area (or at least representative of the cross-sectional area) of the slice 14' from which the stock flows between the forming wires at a linear velocity of, for example, 40 feet per second. It will be appreciated that if we are to assume negligible frictional losses, then we may assume that the stock linear velocity at any point in this inlet between the walls 11' and 12' will be approximately inversely proportional to the ratio between the cross-setcional area at the location in question and the cross-sectional area of the slice itself.
  • the surface 12a of the floor or bottom wall 12 is a relatively smooth straight surface that slopes downwardly slightly toward the forming wire 20 and the angle of slope is indicated at B schematically in FIGURE 6 with reference to the wire line WL, and it will be noted that this angle of slope B (i.e., shown to be expressed in terms of total drop in the floor 12a, etc. of FIGURE 4 per substantially 5 to 10 feet from A of FIGURE 6 to 14 of FIGURE 4 is preferably in the neighborhood of about /2 to 5 or even 10 inches) depending upon the type of inlet desired.
  • the purpose of the inlet is to feed the stock through the slice 14' in generally substantially parallel alignment with respect to the bottom forming wire 20 so the floor 12a should have only a very slight downward slope in the neighborhood of about 1 to 3 from the horizontal, and preferably about 2 as here shown in order to permit stock flow out of the inlet during shutdown and avoid the collection of pools of stock on the surface of the floor 12a during such shutdown of the device.
  • the bump-like turbulence generators indicated in FIG- URE 4 generally at 15 and 16 in the intermediate section R of the channel are mounted only on the roof of the channel.
  • the forward section of the channel R is defined between two relatively narrow wall sections of the roof 11B and the floor 12B which provide a channel spacing indicated schematically in FIGURES 6 as A that is substantially equal for the full dimension of this exit 14, or terminal section R of the channel, although a nominal taper (compared to that upstream) or reduction in the spacing A between such smooth walls is not precluded and may even be helpful in the final guidance of the stock jet at 14.
  • the roof portion 11B is secured rather rigidly by suitable means such as welds or bolts (not shown) to the roof section 11C of the second section R of the channel, by framing generally indicated at F and F such framing F and F extending the full width of the machine and being connected by bolts or welds (not shown) in such a manner as to afford a generally rigid connection between the intermediate roof section 11C and the exit roof section 11B, leaving the exit roof section 11B to extend in a generally cantilever type mounting longitudinally to the slice 14.
  • suitable means such as welds or bolts (not shown) to the roof section 11C of the second section R of the channel
  • framing generally indicated at F and F such framing F and F extending the full width of the machine and being connected by bolts or welds (not shown) in such a manner as to afford a generally rigid connection between the intermediate roof section 11C and the exit roof section 11B, leaving the exit roof section 11B to extend in a generally cantilever type mounting longitudinally to
  • the slice extremity of the roof portion 11B is provided with a plurality of ears, only one of which is shown at 17, each having pivotal connections 18' to rods 19 that are adjustably connected to a flange portion 20 on the framing F via twin lock nuts 21' and 22' which afford limited adjustment of the rod 19 longitudinally or axially so as to aflord limited local adjustment of the relative spacing between the slice extremity of the roof wall portion 11B and the channel floor portion opposite thereto designated 12B.
  • the essential convergence of the walls 11' and 12 thus takes place at the first channel section R and the second channel section R which are already indicated as converging approximately along an angle of convergence B of about 3 to 5, and preferably about 3.
  • the final roof portion 118 securely anchored to the intermediate roof portion 11C is carried by a cross-machine pivot, indicated generally at 30' in FIGURE 4.
  • the pivot 30 is carried in mating blocks 30a and 30b carried on the forward end of a generally rigid cross-machine frame element F which also carries the forward end of the roof portion 11D of the first channel section R
  • the connected crossmachine framing sections F and F also have an car 31 carrying a pivot 32 at opposite sides of the machine (only one of which being shown in FIGURE 4) which pivots 32 are connected through motors shown schematically at 33 to tie rods 34 which are in turn mounted on the fixed framing F by pivots 35'.
  • the motor 33' is of conventional structure and is used to coact with the tie rods 34 to lift the forward roof wall portions 11C and 11B simultaneously in and out of operating position and to leave open a corresponding fiat smooth merging sequence of wall surfaces 12c and 12b which form the continuation of the floor 12a for the bottom of the channel R from the inlet 13' down to the slice 14- at the gradual slope of approximately 2 hereinbefore mentioned. It will thus be seen that the swinging of the roof portions 11C and 11B out of operating position will leave exposed an open smooth flat floor area 12c'12b' which will not collect pools of stock and which can be readily worked on to the extent required and will be readily exposed as a clean smooth surface for this purpose.
  • turbulence generators are indicated generally at 40' and 41 in the form of transversely extending rod banks, which will be described in greater detail hereinafter, but which will be understood to be defined by a multiplicity of relatively small abutments extending between the walls 11' and 12 to afford support thereto and also to afford controlled reduction in the cross-sectional area in the immediate location thereof and further, it being generally rods, terminating abruptly at the down stream end thereof for desired vortex turbulence generation in the stock flowing past such rodsv
  • the upstream sides of the rods are smooth and rounded so as not to collect fibers or strings thereon.
  • the particular details of the framing F do not require additional description, since the general nature of crossmachine framing and mounting of pivots such as the pivots 35 will be fully understood by those skilled in the art.
  • the cross-machine or transversely flowing stock 50' at the level L is indicated as the stock which enters the inlet 10' initially from one side of the machine and then flows downwardly through.
  • a perforated body indicated generally at 51' which actually constitutes a multiplicity of transversely spaced tubes only one of which 52' is shown in FIGURE 4.
  • These tubes are shown as being provided with a suitable noncorrosive cylindrical liner 53' which is preferably synthetic rubber or some other noncorrosive material that is mounted in cylindrical stainless steel spacers or backers 54 which are mounted in alignment with perforations in a top cross-beam 55' and a bottom cross-beam 56 to complete the extension of the tubular conduits 52, each of which have a substantial length-to-diametcr ratio of at least 7:1 and preferably in the neighborhood of 10 to 15:1 or more, depending upon the space available for teh mounting of these tubes 52, Again, it will be appreciated that the essential concept of fiber distribution within the individual tubes 52 by virtue of high velocity stock flow vertically downwardly therethrough is accomplished preferably by the use of the length-to-diameter ratios specified.
  • the alignment of stock in the jet streams within the tubes 52' is the first step in converting the stock from the transverse flow in the inlet 50' to flow in a longitudinal direction, even though the stock flows directly out of the tubes 52 and against the channel floor at 12d to impinge thereon and develop lateral stock flow components as well as additional longitudinal stock flow components in the direction of the channel inlet 13'.
  • the impingement of stock against the floor 12d which functions as a bafiie results in a general change in direction of stock flow of at least about (in this case substantially 90) which effects by virtue of such impingement and turning of the stock streams the required reconversion of lateral flow components in the stock so that the stock is spread laterally in such a manner that it will tend to enter the channel inlet 13' at approximately the same or at least a substantially uniform transverse pressure profile and overall stock linear velocity.
  • FIGURE 9 it will be seen that the stock flows from a fan pump FP', indicated only as an arrow for schematic purposes, upwardly through a vertical channel 60' and into a cross-machine channel 61'.
  • the general profile shown in FIGURE 8 is really a top plan of FIGURE 9 of the channel 61' showing an enlarged inlet end 61a and a relatively narrow opposite end 61b.
  • the channel 61' thus extends in a cross-machine direction but it diminishes in cross-sectional area in the cross-machine direction.
  • the overall cross-machine channel 61 need not be built for stock recirculation therethrough and can simply be mounted on a structural arm 62 extending outwardly from the narrow end 61b and mounted on a conventional supporting pillar 63, while the inlet end 6111' is also mounted on a corresponding supporting pillar 64 in corresponding manner so that the cross-machine channel 61' will be maintained generally horizontal.
  • a source of gas such as air A under pressure is shown diagrammatically being fed through a control valve CV into the top of the crossmachine channel 61 so as to maintain a predetermined superatmospheric pressure on top of the level (L' of FIGURE 4) of the stock in the cross-machine channel 61'.
  • the combination of the taper or diminution in crosssectional area in the channel 51' and the superatmospheric air pressure maintained on the top thereof will have the efiect of presenting stock to the top of each of the small perforations or mouths for the tubes (only two of which are indicated at 52', 52' and dotted lines in FIGURE 9) so that a generally uniform cross-machine pressure is exerted against the stock at the mouth or tops of each of the tubes 52 and the stock jet or stream generated therein will thus be substantially uniform in velocity, volume, turbulence and other characteristics.
  • These tubes 52, 52' will then feed the stock into the channel R which is shown only from the rear in FIGURE 9' and then schematically in order to avoid confusing the view.
  • FIGURE 10 In an alternative embodiment also shown schematically, in FIGURE 10 is will be seen that a fan pump FP1 feeds stock into the inlet side 71a of a generally cylindrical tapered header 71 extending in cross-machine direction toward a relatively narrow exit end 71b, from which a certain amount of stock is recirculated through the conduit indicated at 75' back into the inlet of the fan pump FP1' and makeup stock MS is also fed into the inlet of the fan pump FP-l to maintain the desired amount of total stock entering the tapered cross-machine header 71'.
  • the tapered cross-machine header 71 will thus provide by means of pressure control from the fan pump FP-l and the effect of the gradually diminishing cross-sectional area of the body of the header 71' itself a generally transversely uniform inlet pressure into the mouths 152a, 152a of the multiplicity of transversely spaced tubes, only two of which are indicated schematically at 152', 152' in FIGURE 10, so that the stock will flow in jets downwardly into the channel inlet indicated in FIGURE 10 as R400 corresponding to the channel R of FIG- URE 9.
  • the crosssectional area indicated by the number 12 represents a number of units which correspond in cross-sectional area to a linear velocity of 40 feet per second.
  • the open area A in the region of the stock jets or tubes (hereinbefore described at 52') is comparatively limited and a high velocity high pressure stock jet is desired in this area.
  • the linear velocity in the tubes 52' expressed in terms of the overall open area A will preferably range from about the slice speed to twice the slice speed, or expressed in the numerical terminology, the area ratios A 'zA will range from 1:1 to 2:1 and are preferably about 12:7.
  • the impingement of these jets is preferably carried out against the floor 12d of the overall channel section R for the reason that this simplifies the structure and the stock then immediately impinges upon the first set of turbulence generators 40
  • the individual turbulence generators 40' and 41' in the two banks are actually formed by through bolts 40a and 41a extending through the fioor 12 and in threaded engagement in the roof 11' seating in appropriate roof recesses annular locking devices 40b and 41b in the roof 11 (which are shown in full view for purposes of simplifying the drawing) which provide the necessary annular recess to receive the top of the rod cover 40c and 410 which in each case is preferably a noncorrosive material such as a solid elastomer (i.e.
  • FIGURE 5 is concerned primarily with the concepts of turbulence generation. It will be seen from FIGURE 5 that, looking upwardly toward the roof as the view VV of FIGURE 4 indicates, one Will note the discharges of the transversely spaced tubes indicated at 52f, 52g and 52h in the bottom perforate plate hereinbefore described by the reference numeral 56.
  • the tubes 52 are indicated as having diameters D which are spaced on centers M such that the overall open area is A which is described hereinbefore as being preferably an open area A equalling in total to from 50% to about of the slice cross-sectional area A
  • the tubes 52' should have relativelly small diameters in the neighborhood of about 1 inch and should be approximately 12 inches in length so as to effect the desired stock jet generation and this will result in their centers being approximately 2 inches apart in the spacing M herein indicated for the diameters D in FIGURE 5.
  • the spacing arrangement can be changed and the open area can be changed the-rein such that the diameters D may range from /2 to 1 /2 inches and the spacing between the centers thereof may range from slightly more than D to as much as two or three times D
  • the stock impinges against the floor 12d as indicated in FIGURE 4, and then makes the right angle turn.
  • the stock flows into a chamber area having a substantially greater cross-sectional area A which numerically speaking affords a cross-sectional area ratio A 'zA ranging from about 7:20 to 60, and is preferably about 7:40, which affords a deceleration of stock velocity that averages such that the stock velocity is reduced from the jet velocity to about to Ms of the jet velocity in the initial impingement, deceleration and turning chamber indicated schematically at R in FIGURE 6.
  • the stock then proceeds into the inlet indicated diagrammatically at A in such a manner as to have imposed on the stock a primary velocity increase in the direction of the slice A by virtue of the converging walls.
  • the walls 11' and 12 preferably converge along a general angle of convergence of about 3 to 5, but under certain conditions this range may be expanded to from 1 to It must be appreciated that a pair of closely spaced walls 11' and 12' in the total absence of any turbulence generating devices 40, 41, 15', 16, etc. may extend for a very substantial longitudinal dimension (much greater than the approximately 4 or 5 feet here shown) so as to impart to the stock a generally uniform cross-machine velocity profile as well as imparting the desired turbulence within the stock itself.
  • cross-machine velocity profile we refer to the longitudinal speed of stock at various cross-machine locations in a given region such as along a plane taken through the line A in FIG- URE 6.
  • At least the first two sequences S and S be defined by abutments which terminate abruptly at the downstream side so as to effect vortex turbulene generation and so as to e-fiiect relatively drastic turbulence generation, compared to that generated later on.
  • this is done using a multiplicity of rod banks, in which banks each rod 40 403, 4012', etc. will be generally cylindrical in form and in the case of the first sequence S will have approximately a diameter D of about 1 /2 inches.
  • the center spacing therebetween is preferably about twice the diameter hence M is preferably 2 times D in order to provide an open area of approximately 50% and thus obtain the desired turbulence.
  • the open area may range from perhaps about 25% to 75%, but 50% has been found to be preferable and the particular center-to-center spacing M is also found to be significant in that the individual rods or abutments in the first bank 40' will leave trailing wakes and this is desirable.
  • the rods in the initial bank 40 are of substantial size and are smoothly curved at their upstream ends so that they will not collect fibers, strings, or other matter and they will remain clean. This is very important from the point of view of continuous operation of the device.
  • the function involves that of having turbulence in a condition of partial but incomplete decay as the stock impinges upon the relatively smaller smooth round upstream surfaces of the rod bank 41, as indicated in connection with the individual rods 41f, 41g, 4111', 411', etc.
  • the individual rods 41 are about 1 inch in diameter which is approximately a preferred size so that the relationship between the diameters D 'zD will be about 120.9 to 0.5 and preferably about 3:2.
  • the upstream rods are of comparatively large size so that it will be possible to make sure that there will be no collection of fibers or the like thereon.
  • the net result will be a velocity increase in the neighborhood of about as the stock moves from the location A at the oncoming side of the rod bank to the middle of the rod bank 40 at the location A and then as the stock completes the sequence S of the initial sequence herein described, the tock exits from the initial rod bank 40' and reaches a substantially greater cross-sectional area A4 indicated in FIGURE 6. It will be appreciated that the overall cross channel crosssectional areas indicated by the units A ':A :A will in effect constitute decreases in the neighborhood of ratios of approximately 40:35 to 39:33 to 38, etc.
  • each sequence is in effect a cycle through which the stock is put sequentially from a minimum to a maximum and then to a minimum or conversely from a maximum then to a minimum and back to a maximum cross-sectional area.
  • each sequence goes through the cycle from maximum to minimum to maximum cross-sectional area, and it will be appreciated that the second maximum cross-sectional area is slightly smaller than the first, in other words A, is a maximum that is slightly smaller than A because of the general convergence of the walls and the general reduction in cross-sectional area of the channel which is undergone during the overall longitudinal movement of the stock through the channel.
  • each sequence S S S S will have a general longitudinal dimension which is indicated schematically in FIGURE 5 in that it will involve the flow of stock approaching whatever the turbulence generating device might be plus the flow of stock past the turbulence generating device and then the flow of stock into what amounts to the subsequent maximum cross-sectional area, which for the sequence S involves the sequence shown schematically in FIGURE 6 as A A A
  • the exact longitudinal dimension is not absolutely critical, but it may be considered to be a dimension from approximately midway between one set of turbulence generators to midway between the next set of turbulence generators, as in the case of the later sequences S2,, S3: S4-
  • the two rod banks 40 and 41 thus preferably have the same open areas and this is preferably approximately a 50% open area so that there is an effective doubling of the velocity at least in the secondary or superimposed stock velocity at each of the sequences 8, and S and the overall turbulence generation is such that the second rod bank 41 receives turbulence from the upstream rod bank 40 so as to keep the upstream faces of the rods 41' clean and permit the use of relatively smaller diameter D rods in this bank.
  • the instant inlet provides still another type of turbulence generation in the latter sequences S and S (i.e. at least the last two sequences) before the exit X.
  • the exit chamber X is preferably defined by a pair of smooth closely spaced walls that are generally equidistant and effect whatever turbulence generation they are capable of effecting purely by virtue of the fact that the stock stream flowing thereby is moving at a very rapid rate and the walls are necessarily standing still.
  • This exit region X preferably has a longitudinal dimension that is at least as great as that of the last sequence S and preferably at least as great as twice or more the longitudinal dimension of the last sequence S
  • the exit section X' has a longitudinal dimension that is substantially three times that of the last sequence S This results in turbulence decay. It is desired to obtain a certain amount of turbulence decay in the final exit chamber.
  • the amount of turbulence decay will depend upon the velocity of stock in the channel R. If the velocity is very slow, the turbulence generating devices will have to be more closely spaced and the exit chamber X will not be very long, because the benefit of turbulence generation and defiocking will not want to be lost completely. On the other hand, if the stock speed is relatively high even the closely spaced walls of the exit chamber X will impart a certain amount of turbulence and they will permit a great deal of equalizing or generation of uniformity in the fiber distribution if they are at least equal to two or three times the longitudinal dimension 8., of the last sequence.
  • these turbulence generating devices are sheargenerators. In other words, they do not rely solely on the vortex turbulence generation concept that necessarily results from the abrupt downstream ends of rods. Instead, they impart a general shearing effect to the stock stream.
  • the ratio of A to A is about 4:3 and the velocity increase is thus the inverse of this cross-sectional area ratio by the end of the second sequence S
  • the cross-sectional areas go through the ranges A and A A in maximum minimum maximum such that A is in a cross-sectional area ratio to A within the range of about A :A ranging from 4:1 to 4:3, but preferably about 2:1.
  • the overall channel R could have the general characteristics of the exit channel X if it had a great enough longitudinal dimension.
  • the difficulty is that paper machines do not provide for this much space. Accordingly, it is necessary to add to the device for converting the cross-machine stock flow into longitudinally directed stock flow a certain number of turbulance generators which will greatly diminish the overall exit stage dimension X.
  • These various turbulence generators 40, 41', 15 and 16 will not completely eliminate the exit stage X but they will reduce the dimension thereof materially and make the size of the machine workable for practical purposes.
  • At least the first two sequences S and S are preferably of the vortex generating type, as in the case of the rods 40 and 41; whereas it has also been found that preferably the last two sequences here designated S and S are preferably of the shear or approximately shear generating devices in the sense that a lower scale of turbulence will be fed into the exit chamber X' and a better fiber distribution is ultimately obtained at the slice 14'.
  • a shear generator which need not be described in complete detail, since this and the other applications hereinbefore referred to are actually incorporated herein by reference.
  • the purpose of a shear generator is to cause abrupt convergence followed by abrupt divergence (which would be from the area A to the area A during the abrupt convergence and from the area A to the area A for the abrupt divergence in such a manner as to superimpose an abrupt velocity change upon the stock (although this velocity change is actually at a rate that is from A to perhaps )1 or the rate of velocity change that is imposed by the upstream rod banks 40' and 41).
  • the purpose of shear generators is to minimize vortex type of turbulence generation by separation of the stock from the walls during the downstream or divergent flow of each sequence S and S
  • the angle of convergence 15a between the surface of the roof 11c and the turbulence generator 15' is approximately an angle of 15 in the device here shown. This is a relatively abrupt angle of convergence and a more gradual angle could be used ranging perhaps down to as low as about 3 to 5 and up to as much as about 20 for the more drastic conditions.
  • the angle of divergence at the off-running side is of somewhat greater importance from the point of view of avoiding separation of the stock from the wall.
  • the angle of divergence 15b is also here indicated as being about 15, although it may range from this approximate maximum down to as low as about 3 to 5 depending upon the speed of stock.
  • the roof 110' is provided with a pair of cross-machine slots into which the anchoring portions 150 and 16c of the turbulence generators 15 and 16' may be slipped and retained for ordinary operation. These devices are thus moved in and out of position by sliding the same in the transverse or cross-machine direction which is a convenient arrangement.
  • the turbulence generators 15 and 16 extend the full width of the channel section R and althouh they are shown in FIGURE 7 in full view it will be appreciated that the longitudinal section at any location across the machine will be the same.
  • the actual cross-sec tional dimension in the minimum area A is slightly smaller than in the minimum area A and in each case these dimensions are in a ratio to the dimension A of approximately 1:4 to 3:4, so the velocities at the locations A and A are actually greater than the slice longitudinal stock velocity and this is desired for purposes of imparting a final shearing force to the stock approaching the slice 14'.
  • the floor 12c in the second section R is at approximately an angle of about 2 to the horizontal or to the wire line indicated by the line marked W in FIGURE 7.
  • the roof 110 which is a continuation of the roof 11a of the first section R in the operating arrangement is approximately at an angle of about 5 or 5% to the wire line W, so that the angle of convergence in the preferred embodiment here shown is slightly over 3.
  • the centerline plane for the channel R is a line indicated generally at P--P', which is really a centerline plane PP that is used essentially for reference purposes. It will be seen that the convergence and divergence in the stock stream created by the shear generators 15' and 16 is not symmetrical with respect thereto and this seems to impart an improvement in the overall fiber distribution.
  • the peak for the first of these sequences S is the peak indicated at the apex of the triangmlar configuration at 150.” for the shear turbulence generator 15'.
  • L the distance L (FIGURE 5) that is approximately within the range of 2 to 5 times the dimension M which is the center-to-center spacing in the upstream vortex turbulence generating rod bank 41', so that the convergence will be maximized at the region of incomplete turbulence decay from the upstream turbulence generating device, which in this case is the rod bank 41'.
  • the peak 16d for the downstream shear generator in that it also results in maximum stock convergence at a region of only partial decay from the upstream turbulence generator 15.
  • the rapid flow of stock past the shear turbulence generators 15' and 16, respectively preferably does not result in separation from the channel walls or the channel roof lie in this instance. It is known that in the case of relatively high speeds pure water will separate from a divergent wall if the angle of divergence from the centerline or center plane of the channel is greater than about 7.
  • angles of divergence as high as 12', 13 or even 14 are permitted.
  • simple arithmetic will reveal that the angle of divergence 152' and 16e' is approximately 13 /2 in each case. This is about the maximum tolerated for practical purposes. It may result in a slight amount of separation but it does not result in a significant amount of separation or a harmful amount of separation, particularly in view of the fact that the exit channel X is at least twice and preferably three times the longitudinal dimension 8., of the last sequence of shear turbulence generation.
  • these turbulence generators 15 and 16' are designed to obtain the maximum desired turbulence under the circumstances without causing any undesirable results at the ultimate slice 14' and this is done by using a rather drastic angle of divergence, preferably, in conjunction with a reasonably long exit channel X' which has the description already given. It will be appreciated that the angle of divergence may be reduced from the indicated 13 or 14 down to as low as 3, 5 or 6 in certain instances and in the case of certain types of stock this is not a difficult problem since the generators 15' and 16' may be readily constructed so as to reduce this angle of divergence.
  • shear turbulence generator 15' and 16' readily accommodates this type of change since the variable involves nothing more than adding to or subtracting from the material employed in the off-running side of the turbulence generator relative to the center plane PP' of the channel.
  • the channel itself may have its angle of convergence increased or decreased somewhat under certain circumstances, and this will involve a rather major change in the overall structure.
  • the shear generators 15 and 16' may be altered to obtain whatever angle of divergence 152 and 162 may be desired or may be found to be desirable.
  • the slice jet 14' is so positioned as to be substantially aimed at the previously re-

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US467664A 1965-06-28 1965-06-28 Paper forming assembly and method Expired - Lifetime US3382143A (en)

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Application Number Priority Date Filing Date Title
US467664A US3382143A (en) 1965-06-28 1965-06-28 Paper forming assembly and method
DE19661511229 DE1511229A1 (de) 1965-06-28 1966-06-21 Verfahren und Vorrichtung zum Entwaessern einer waessrigen Papierstoffsuspension bei Papiermaschinen
BE683061D BE683061A (enrdf_load_stackoverflow) 1965-06-28 1966-06-24
LU51407A LU51407A1 (enrdf_load_stackoverflow) 1965-06-28 1966-06-24
NL6608977A NL6608977A (enrdf_load_stackoverflow) 1965-06-28 1966-06-28
ES0328517A ES328517A2 (es) 1965-06-28 1966-06-28 Procedimiento y aparato de desaguado de pulpa o material acuoso de produccion de papel.

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US467664A US3382143A (en) 1965-06-28 1965-06-28 Paper forming assembly and method

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US3382143A true US3382143A (en) 1968-05-07

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US467664A Expired - Lifetime US3382143A (en) 1965-06-28 1965-06-28 Paper forming assembly and method

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US (1) US3382143A (enrdf_load_stackoverflow)
BE (1) BE683061A (enrdf_load_stackoverflow)
DE (1) DE1511229A1 (enrdf_load_stackoverflow)
ES (1) ES328517A2 (enrdf_load_stackoverflow)
LU (1) LU51407A1 (enrdf_load_stackoverflow)
NL (1) NL6608977A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3855057A (en) * 1967-11-02 1974-12-17 Beloit Corp Paper formation utilizing a large diameter suction roll
EP0002841A1 (en) * 1977-10-11 1979-07-11 THE PROCTER & GAMBLE COMPANY Microturbulence generator for papermachine headbox and method of using the same
US4324820A (en) * 1980-07-18 1982-04-13 St. Regis Paper Company Method and apparatus for coating a paper web
US4414061A (en) * 1975-02-20 1983-11-08 Australian Paper Manufacturers Limited Twin wire paper forming apparatus
CN107338667A (zh) * 2016-04-28 2017-11-10 维美德技术有限公司 纤维幅材机的支撑框架结构及纤维幅材机

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3855057A (en) * 1967-11-02 1974-12-17 Beloit Corp Paper formation utilizing a large diameter suction roll
US4414061A (en) * 1975-02-20 1983-11-08 Australian Paper Manufacturers Limited Twin wire paper forming apparatus
EP0002841A1 (en) * 1977-10-11 1979-07-11 THE PROCTER & GAMBLE COMPANY Microturbulence generator for papermachine headbox and method of using the same
US4324820A (en) * 1980-07-18 1982-04-13 St. Regis Paper Company Method and apparatus for coating a paper web
CN107338667A (zh) * 2016-04-28 2017-11-10 维美德技术有限公司 纤维幅材机的支撑框架结构及纤维幅材机
EP3239396A3 (en) * 2016-04-28 2018-01-17 Valmet Technologies, Inc. A support frame structure for a fiber web machine and a fiber web machine
CN107338667B (zh) * 2016-04-28 2019-10-18 维美德技术有限公司 纤维幅材机的支撑框架结构及纤维幅材机

Also Published As

Publication number Publication date
DE1511229A1 (de) 1969-10-16
NL6608977A (enrdf_load_stackoverflow) 1966-12-29
BE683061A (enrdf_load_stackoverflow) 1966-12-01
LU51407A1 (enrdf_load_stackoverflow) 1966-08-24
ES328517A2 (es) 1967-04-01

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