US3607625A - Headbox - Google Patents

Headbox Download PDF

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Publication number
US3607625A
US3607625A US698633A US3607625DA US3607625A US 3607625 A US3607625 A US 3607625A US 698633 A US698633 A US 698633A US 3607625D A US3607625D A US 3607625DA US 3607625 A US3607625 A US 3607625A
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US
United States
Prior art keywords
slice
headbox
stock
downstream
elements
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US698633A
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English (en)
Inventor
Lester M Hill
Joseph D Parker
Richard E Hergert
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Beloit Corp
Original Assignee
Beloit Corp
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Filing date
Publication date
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Publication of US3607625A publication Critical patent/US3607625A/en
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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

Definitions

  • This invention relates generally to a headbox for a papermaking machine, and more particularly to a headbox construction in which the slice chamber'includes a plurality of passages formed by elements in the direction of stock flow to uniformly direct stock towards the slice opening at the downstream of said slice chamber.
  • the dispersing activity that occurs on the Fourdrinier table is an important supplement to the turbulence generated in the headbox and as a rule, the drainage on a Fourdrinier table is deliberately retarded to allow sufficient treatment of the undrained suspension to obtain uniform fonnation.
  • the fiber suspension is drained comparatively much more rapidly with considerably less activity generated in the undrained suspension. It follows that the formation of the sheet formed on a suction box or flat box Fourdrinier is much more sensitive to the characteristics of the headbox discharge 'that that of a conventionally formed sheet.
  • a basic limitation in headbox design has been that the means for generating turbulence in fiber suspensions in order to disperse them have been comparatively large-scale devices only. With such devices, it is possible to develop small scale turbulence by increasing the intensity of turbulence generated. Thus the turbulence energy is transferred naturally from large to small scales and the higher the intensity, the greater the rate of energy transfer and hence, the smaller the scales of turbulence sustained. However, a detrimental efiect also ensued from this high-intensity large-scale turbulence namely the large waves and free surface disturbance developed on the Fourdrinier table. Thus a general rule of headbox performance has been that the degree of dispersion and level of turbulence in the headbox discharge were closely correlated; the higher the turbulence, the better the disperslon.
  • headbox design under this limiting condition then, one could choose at the extremes, either a design that produces a highly turbulent, well-dispersed discharge, or one that produces a low-turbulent, poorly dispersed discharge. Since either a very high level of turbulence or a very low level (and consequent poor dispersion) produces defects in sheet formation on the Fourdrinier machine, the art of headbox design has consisted of making a suitable compromise between these two extremes. That is, a primary objective of headbox design up to this time has been to generate a level of turbulence which was high enough for dispersion, but low enough to avoid free surface defects during the formation period.
  • the unique and novel combination of elements of the present invention provide for delivery of the stock slurry to a forming surface of a papermaking machine having a high degree of fiber dispersion with a low level of turbulence in the discharge jet. Under these conditions, a fine scale dispersion of the fibers is produced which will not deteriorate as the turbulence decays away; at least it will not deteriorate to the extent that occurs in the turbulent dispersions which are produced by conventional headbox designs. It has been found that it is the absence of large-scale turbulence which precludes the gross reflocculation of the fibers since flocculation is predominately a consequence of small scale turbulence decay and the persistence of the large scales. Sustaining the dispersion in the flow on the Fourdrinier wire then, leads directly to improved formation.
  • the method by which the above is accomplished is to pass the fiber suspension through a system of parallel channels of uniform small size but large in percentage open area. Both of these conditions, uniform small channel size and large exit percentage open area, are necessary.
  • uniform small channel size and large exit percentage open area are necessary.
  • the largest scales of turbulence developed in the channel flow have the same order of size as the depth of the individual channels and by maintaining the individual channel depth small, the resulting scale of turbulence will be small. It is necessary to have a large exit percentage open area to prevent the development of large scales of turbulence in the zone of discharge. That is, large solid areas between the channel's exits, would result in largescale turbulence in the wake of these areas.
  • the flow channel must change from a large entrance to a small exit size. This change should occur over a substantial distance to allow time for the large-scale coarse flow disturbances generated in the wake of the entrance structure to be degraded to the small-scale turbulence desired.
  • the walls defining the channels immediately following the entrance structure should be stiff enough to resist distortion and fluctuation by these coarse flow disturbances and consequent dynamic pressure variations. For this reason, it is important for the entrance to have a reasonably large open area to avoid unreasonably large downstream pressure fluctuations.
  • the more the coarse turbulence in the flow channel is degraded toward a fine scale the less stiff the channel walls need be to resist distortion.
  • the structure for conditioning the flow should consist of gradually converging channels defined by walls which simultaneously slowly converge and gradually decreases in stiffness.
  • the simultaneous convergence of the channel size and the walls defining the channels are complementary effects. Because of the diminishing channel depth, the pressure fluctuations are reduced to smaller scale and hence lower intensities which allows thinner walls to be used to define the channel. Because of the diminishing wall thickness, the area between channels approaches the small dimension that it must have at the exit end. This concept of simultaneous convergence is deemed to be an important concept of design of this invention.
  • the slice opening S should be in the order one eighth inch or smaller and the size of the solid areas between the channels at their exits should be much smaller than the size of the channels themselves.
  • the exit open area should therefore be preferably in the order of at least 80 95 percent.
  • open areas in the order of'50 percent and larger are conceivable.
  • the vertical dimension of each of the channels 29, 30 and 31, etc. at the upstream end in the order of I inch andthe overall open area of the perforated plate should preferably be greater than percent.
  • the openings in the distributor should be as small as possible for maintaining the flow pattern small but large enough to avoid plugging. These criteria will vary with the particular application and stock characteristics.
  • papermaking stock is introduced into the tapered inlet 12 through entrance opening 120.
  • a portion of the stock enters orifices 13a, 13b, 130, etc. while the remaining portion exits the tapered inlet 12 through opening 12b for recirculation.
  • the stock From the orifices 13a, 13b, 13c, etc. the stock enters the diffusers 14a, 14b, 140, etc. by means of which the stock is uniformly distributed across the full width of the preslice chamber 11b.
  • the distribution of stock across the width of the preslice chamber is of a coarse nature having a scale of turbulence or variations in the order of a few inches.
  • the coarsely distributed stock is then forced through the perforations in plate 15 by means of which the scale of turbulence is somewhat reduced but remains far above the desired level for formation of a web.
  • the stock then enters the channels 29, 30, 31, etc. under conditions of relatively coarse and intense turbulence.
  • the upstream ends of the trailing members are supported by the plate 15 and they are strong enough to accommodate the relatively large scale and intensity of the turbulence in the stock.
  • the intensity and degree of turbulence is likewise decreased.
  • the channels are narrow and bounded by flexible walls. At this end the scale of turbulence has been diminished to acceptable papermaking standards.
  • This diminishing turbulence is accomplished by reducing the channel size while still allowing coarse particles to pass by reason of the flexibility of the trailing members defining the channels.
  • the turbulence of the stock, therefore, in the channels is continually degraded from a coarse intense condition to a fine-scale low level.
  • the walls of the channels are graduated in thickness and stiffness accordingly.
  • the ultimate scale of turbulence in the flow from the channels is governed by the size of the channels near the downstream end, and the intensity is determined by the velocity of flow through the channels which in turn is determined by the number of channels. In this manner the scale and intensity of the discharge flow can be independently controlled.
  • FIGS. 2 through 12 show additional details and other forms of the present invention.
  • a headbox 40 of a somewhat simplified design comprises a tapered inlet header 41 having an inlet opening 42 and an overflow opening 43.
  • the front wall of the header 40 comprises a perforated plate 44 having a multiplicity of perforations 45, 46, etc. therein. These perforations are preferably in the form of orifices and provide for open communication between the inlet header and a slice chamber generally designated by the numeral 47.
  • the slice chamber 47 comprises top 48 and bottom 49 walls converging in the longitudinal or machine direction and terminating at a slice portion S2. Appropriate transversely spaced sidewalls are provided at the front and rear end of the slice chamber. Extending longitudinally within the slice chamber 47 are a plurality of trailing elements 50, 51, 52, etc.
  • each of these trailing elements is attached to the perforated plate 44 at the upstream end of the slice chamber 47.
  • the trailing elements extend for approximately the full length of the slice chamber and are not attached to any other part of the chamber other than at the perforated plate 44.
  • the trailing elements are thus permitted to float freely within the slice chamber with the exception of their restriction at the point of attachment to the perforated plate 44. With papermaking stock flowing through the slice chamber the trailing elements willform a multiplicity of longitudinally extending flexible channels through which the papermaking stock will flow thereby gradually reducing large-scale turbulence in the papermaking stock while maintaining a high degree of fiber dispersion.
  • the thus-conditioned papermaking stock exits through the slice opening S2 and is deposited on the Fourdrinier wire 53 or on any other appropriate webforming surface.
  • the Fourdrinier wire 53 is supported immediately beneath the slice by a roll 54, commonly referred to as a breast roll.
  • the trailing members may have different forms each of which can be readily adapted to suit a particular operating condition.
  • the flexible members 50, 51, and 52, etc. extend transversely of the slice chamber in the form of a fullwidth sheet, as described in connection with FIG. I, where the transverse dimension of the preslice flow chamber is relatively narrow.
  • FIG. 4 shows the flexible trailing elements extending transversely of the slice chamber with the flexible elements having approximately the same transverse dimension as the slice chamber.
  • the transverse dimension of the individual trailing elements 60, 61, 62, etc. is reduced to a fraction of the transverse dimension of the preslice flow chamber which may be a more practical approach for headboxes having a relatively large transverse dimension.
  • FIG. 3 shows a further embodiment of the present invention and it will be noted that the trailing elements herein consist of a plurality of flexible rods or wires 63, 64, 65, etc. having a generally circular cross-sectional area. This embodiment is particularly useful where stock characteristics require the use of channels of extremely small cross-sectional area.
  • the longitudinal cross-sectional area of the trailing elements 50, 51, 52, etc. is preferably made so as to have its cross-sectional area decrease longitudinally in the direction of flow.
  • the decrease in cross-sectional area is commensurate with the decrease in cross-sectional area of the slice chamber 11a of FIG. I and 47 of FIG. 2. In this manner the complementary effects of simultaneous convergence of the channel size and the flexible elements are obtained.
  • the transverse cross-sectional area remains substantially rectangular as shown in FIG. 7.
  • FIG. 8 shows the cross-sectional area of the trailing elements 50, 51, 52, etc. of FIG. 3 and while this cross-sectional The whole was passed into an oven at 150 C., and kept there for 1-2 minutes. Thereafter, onto the previous layer a second layer (foamed) was spread. which consisted of:
  • PVC paste making resin having a K-value of 72 dioctyl phthalate 100 parts (by weight) 80 parts (by weight)
  • the initial thickness of this layer was 200 microns.
  • the poromeric material thus obtained showed the following air transpiration rates:
  • the release paper was then removed and the system was subjected to a slight tension and subsequently was coupled to a jersey fabric made of polyamide fibers, the second layer being adjacent to the fabric after preliminary having spread on the fabric some plastisol of the first layer which serves as a binder.
  • the poromeric material thus obtained shows the following air transpiration rates:

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  • Paper (AREA)
US698633A 1968-01-17 1968-01-17 Headbox Expired - Lifetime US3607625A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US69863368A 1968-01-17 1968-01-17

Publications (1)

Publication Number Publication Date
US3607625A true US3607625A (en) 1971-09-21

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US698633A Expired - Lifetime US3607625A (en) 1968-01-17 1968-01-17 Headbox

Country Status (10)

Country Link
US (1) US3607625A (de)
BE (1) BE713221A (de)
CH (1) CH493693A (de)
DE (1) DE1761229C3 (de)
ES (1) ES353560A1 (de)
FI (1) FI51229C (de)
FR (1) FR1560071A (de)
GB (1) GB1228248A (de)
NL (1) NL153625B (de)
SE (1) SE354881B (de)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3769153A (en) * 1971-03-19 1973-10-30 Beloit Corp Papermaking machine headbox with multiple stiff, vibrational rods or plates extending downstream in the slice chamber
US3769155A (en) * 1970-02-18 1973-10-30 Voith Gmbh J M Stock inlet system for a paper making machine including converging settling ducts
US3839143A (en) * 1972-06-08 1974-10-01 Beloit Corp Multi-ply two wire former wherein multiple headboxes are used and inflatable air bellows provide adjustments therebetween
US3853695A (en) * 1972-10-12 1974-12-10 S Back Entraining a liquid into a fiber slurry to accelerate it prior to discharge from a flow path onto a forming wire
US3853697A (en) * 1973-03-08 1974-12-10 Beloit Corp Papermaking machine headbox with an upwardly inclined slice chamber portion, an arcuate portion, and a downwardly inclined portion and containing flexible trailing members
US3856619A (en) * 1973-03-07 1974-12-24 Beloit Corp Papermaking machine headbox with slice chamber containing flexible trailing elements having extended edges
US3888729A (en) * 1972-11-06 1975-06-10 Joseph D Parker Papermaking machine headbox slice chamber containing pivotable thin rigid plates with flexible elements attached thereto
DE2501365A1 (de) * 1974-01-17 1975-07-24 Beloit Corp Vorrichtung zur herstellung von mehrschichtigen bahnen
US3902961A (en) * 1972-02-24 1975-09-02 Beloit Corp Adjustable slice lip for a headbox
US3923593A (en) * 1971-12-03 1975-12-02 Beloit Corp Multiple ply web former with divided slice chamber
US3939037A (en) * 1973-03-27 1976-02-17 Beloit Corporation Headbox with flexible trailing elements
US4812208A (en) * 1985-07-30 1989-03-14 Seishi Gijutsu Kenkyu Kumiai Headbox for paper machine with parallel twisted plates
US5082531A (en) * 1990-10-26 1992-01-21 Hasegawa Machinery Limited Head box in a paper machine
US5468348A (en) * 1990-07-10 1995-11-21 Beloit Technologies, Inc. Multi-ply web former and method
US5569360A (en) * 1993-10-29 1996-10-29 Valmet Corporation Multi-layer headbox
US5639352A (en) * 1993-09-03 1997-06-17 J.M. Voith Gmbh Headbox lamellae and method for reducing turbulence thereabout
US6017421A (en) * 1997-07-04 2000-01-25 Voith Sulzer Papiermaschinen Gmbh Headbox with baffle
US20060157215A1 (en) * 2004-12-08 2006-07-20 Vaahto Oy Arrangement in a headbox

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA936722A (en) * 1970-08-31 1973-11-13 A. Betley Raymond Headbox slice chamber
CH608255A5 (de) * 1976-05-11 1978-12-29 Escher Wyss Gmbh
SE421328B (sv) * 1978-04-25 1981-12-14 Karlstad Mekaniska Ab Forfarande och anordning for bildande av en flerskiktsmeldstrale
DE3134783A1 (de) * 1981-09-02 1983-03-17 Naučno-proizvodstvennoe ob"edinenie bumagodelatel'nogo mašinostroenija, Leningrad Papiermaschinen-stoffauflauf
US4534399A (en) * 1984-06-27 1985-08-13 Crown Zellerbach Corporation Paper stock diffuser system
DE3502885A1 (de) * 1985-01-29 1986-07-31 Mitsubishi Jukogyo K.K., Tokio/Tokyo Papiermaschinen-stoffauflauf
DE3723922C2 (de) * 1987-07-18 1993-10-14 Trefz Wolfgang Dipl Ing Fh Turbulenzerzeuger für den Stoffauflauf einer Papiermaschine
DE19806698A1 (de) * 1998-02-18 1999-08-19 Voith Sulzer Papiertech Patent Vorrichtung zur Verminderung von Ablösewirbeln an Strömungsendkanten
CN103726383A (zh) * 2013-04-22 2014-04-16 太仓派欧技术咨询服务有限公司 一种玻璃纤维浆料流动导向的层状导流架

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB236864A (en) * 1925-03-31 1925-07-16 Walther Voith Improvements in and relating to fourdrinier or other paper-making and like machines
US2394509A (en) * 1943-05-03 1946-02-05 Leo J Boettinger Head box slice for papermaking machines
US2832268A (en) * 1954-07-29 1958-04-29 Outario Paper Company Ltd Method of improving flow of stock from the stock inlet of a paper machine
US3135650A (en) * 1960-01-08 1964-06-02 Time Inc Flow system for paper formers
GB1026276A (en) * 1962-04-12 1966-04-14 Karlstad Mekaniska Ab Improvements relating to papermaking
US3272233A (en) * 1963-03-08 1966-09-13 Diamond Int Corp Taper flow inlet

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB236864A (en) * 1925-03-31 1925-07-16 Walther Voith Improvements in and relating to fourdrinier or other paper-making and like machines
US2394509A (en) * 1943-05-03 1946-02-05 Leo J Boettinger Head box slice for papermaking machines
US2832268A (en) * 1954-07-29 1958-04-29 Outario Paper Company Ltd Method of improving flow of stock from the stock inlet of a paper machine
US3135650A (en) * 1960-01-08 1964-06-02 Time Inc Flow system for paper formers
GB1026276A (en) * 1962-04-12 1966-04-14 Karlstad Mekaniska Ab Improvements relating to papermaking
US3272233A (en) * 1963-03-08 1966-09-13 Diamond Int Corp Taper flow inlet

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3769155A (en) * 1970-02-18 1973-10-30 Voith Gmbh J M Stock inlet system for a paper making machine including converging settling ducts
US3769153A (en) * 1971-03-19 1973-10-30 Beloit Corp Papermaking machine headbox with multiple stiff, vibrational rods or plates extending downstream in the slice chamber
US3923593A (en) * 1971-12-03 1975-12-02 Beloit Corp Multiple ply web former with divided slice chamber
US3902961A (en) * 1972-02-24 1975-09-02 Beloit Corp Adjustable slice lip for a headbox
US3839143A (en) * 1972-06-08 1974-10-01 Beloit Corp Multi-ply two wire former wherein multiple headboxes are used and inflatable air bellows provide adjustments therebetween
US3853695A (en) * 1972-10-12 1974-12-10 S Back Entraining a liquid into a fiber slurry to accelerate it prior to discharge from a flow path onto a forming wire
US3888729A (en) * 1972-11-06 1975-06-10 Joseph D Parker Papermaking machine headbox slice chamber containing pivotable thin rigid plates with flexible elements attached thereto
US3856619A (en) * 1973-03-07 1974-12-24 Beloit Corp Papermaking machine headbox with slice chamber containing flexible trailing elements having extended edges
US3853697A (en) * 1973-03-08 1974-12-10 Beloit Corp Papermaking machine headbox with an upwardly inclined slice chamber portion, an arcuate portion, and a downwardly inclined portion and containing flexible trailing members
US3939037A (en) * 1973-03-27 1976-02-17 Beloit Corporation Headbox with flexible trailing elements
DE2501365A1 (de) * 1974-01-17 1975-07-24 Beloit Corp Vorrichtung zur herstellung von mehrschichtigen bahnen
US4812208A (en) * 1985-07-30 1989-03-14 Seishi Gijutsu Kenkyu Kumiai Headbox for paper machine with parallel twisted plates
US5468348A (en) * 1990-07-10 1995-11-21 Beloit Technologies, Inc. Multi-ply web former and method
US5082531A (en) * 1990-10-26 1992-01-21 Hasegawa Machinery Limited Head box in a paper machine
US5639352A (en) * 1993-09-03 1997-06-17 J.M. Voith Gmbh Headbox lamellae and method for reducing turbulence thereabout
US5569360A (en) * 1993-10-29 1996-10-29 Valmet Corporation Multi-layer headbox
US6017421A (en) * 1997-07-04 2000-01-25 Voith Sulzer Papiermaschinen Gmbh Headbox with baffle
US20060157215A1 (en) * 2004-12-08 2006-07-20 Vaahto Oy Arrangement in a headbox
US7504003B2 (en) 2004-12-08 2009-03-17 Vaahto Oy Arrangement in a headbox

Also Published As

Publication number Publication date
DE1761229A1 (de) 1972-04-13
SE354881B (de) 1973-03-26
CH493693A (de) 1970-07-15
DE1761229B2 (de) 1973-11-08
DE1761229C3 (de) 1979-12-20
FR1560071A (de) 1969-03-14
NL153625B (nl) 1977-06-15
GB1228248A (de) 1971-04-15
BE713221A (de) 1968-08-16
FI51229C (fi) 1980-07-09
NL6806412A (de) 1969-07-21
FI51229B (de) 1976-08-02
ES353560A1 (es) 1969-10-01

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