US3769153A - Papermaking machine headbox with multiple stiff, vibrational rods or plates extending downstream in the slice chamber - Google Patents

Papermaking machine headbox with multiple stiff, vibrational rods or plates extending downstream in the slice chamber Download PDF

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Publication number
US3769153A
US3769153A US00126176A US3769153DA US3769153A US 3769153 A US3769153 A US 3769153A US 00126176 A US00126176 A US 00126176A US 3769153D A US3769153D A US 3769153DA US 3769153 A US3769153 A US 3769153A
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United States
Prior art keywords
stock
members
slice
forming surface
headbox
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Expired - Lifetime
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US00126176A
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English (en)
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L Hill
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Beloit Corp
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Beloit Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L39/00—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/02—Head boxes of Fourdrinier machines
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/02—Head boxes of Fourdrinier machines
    • D21F1/028—Details of the nozzle section

Definitions

  • ABSTRACT A headbox structure for feeding a slurry of stock onto a traveling forming surface for a paper making machine including a tapering slice chamber with cantilever supported self-supporting, self-exciting vibrational rods or plates cantilever supported at their upper end and extending in a downstream direction within the slice immediately ahead of the slice opening and operational to reduce the network strength between the fibers as they are delivered onto the traveling forming surface.
  • a further object of the invention is to provide an arrangement for reducing the network strength between fibers just as the stock is delivered onto the traveling fourdrinier surface so that the generation of large scale turbulence within the headbox which was heretofore thought necessary in order to maintain turbulence in the stock as it was delivered onto the wire becomes unnecessary.
  • a limitation in headbox has been that the means for generating turbulence in fiber suspension in order to disperse them has generally been by comparatively large scale devices. With such devices it is possible to develop small scale turbulence by increasing the intensity of the turbulence generated. The turbulent energy is transferred from large to small scale, and the higher the intensity, the greater the rate of energy transfer and the smaller the scale of turbulence sustained. However, a detrimental effect results from the high intensity of large scale turbulence in that large waves and free surface disturbances developed on the fourdrinier surface.
  • headbox design in accordance with the foregoing, the paper machine designer chose a design which he felt obtained maximum turbulence and dispersion without entering the area of the disadvantageous effects of disturbance of the formation of the web on the fourdrinier surface. That is, an objective of headbox design has been to generate a level of turbulence that was high enough for dispersion, but low enough to avoid free surface defects during the formation period.
  • the formation of the sheet formed by the rapid drainage over the suction boxes in the absence of table roll activity directly reflects the poor dispersion in the discharge jet.
  • the turbulence is very high, a wave pattern is generated in the free surface of the flow on the wire as a consequence of the turbulence. With the rapid drainage of the suspension in this case, the formation of the sheet reflects the mass distribution pattern of these waves. In addition to the free surface wave patterns, excessive turbulence may also entrain air and disrupt the thickened fiber mat which have been deposited, and cause formation defects.
  • the stock is first delivered to aheadbox chamber 14 through stock inlet lines 12 and 13 from a suitable stock delivery source.
  • the source will be provided by the usual structure including fan pumps which provide the stock under sufficient controllable flow volumes and pressure to deliver to a traveling fourdrinier surface at the required velocity.
  • the headbox chamber 14 is small relative to the usual chamber, and it will be understood that the size illustrated'is not to be limiting, but any size may be provided which provides stock flow at sufficient turbulence so that dispersion will be maintained as the stock enters the slice unit 11.
  • the slice unit has a slice chamber 17 with an inlet end 15 and a slice opening 16.
  • the chamber is defined by an upper wall 27 and a lower wall 28 and the structure is suitably supported and reinforced such as by members 29 and 30.
  • stock is furnished through the inlet lines 12 and 13 into the headbox 14 whereupon it flows into the slice chamber 17 and out through the slice opening 16 onto a traveling fourdrinier.
  • the slice chamber 17 is tapered from its entry end 15 to the slice opening 16, and as the stock exits through the opening, it flows at the desired velocity relative to the travel of the fourdrinier wire.
  • Means, not shown, may be provided to relatively move the walls 27 and 28 to control the size of the slice opening 16.
  • a plurality of separate vibrational self-exciting thin elongate rod members 20 are cantilever supported at their upper ends and extend downstream in the general direction of stock flow, preferably parallel to each other. They have sufficient stiffness to be sulf-supporting. It has been discovered that cantilever elongate rods constructed in this fashion will be self-exciting due to the flow of stock along their surface in an elongate slice as illustrated. This self-excitation occurs as soon as the stock beings to flow and the excitation is transmitted to the stock and the fibers reducing the fiber-to-fiber friction, which in turn reduces the network strength and attains dispersion throughout travel through the slice and continues its effect onto the wire.
  • This selfexcitation will occur at the natural frequency of the rod members, and they are surrounded by the water which is the carrier for the fibers of the stock.
  • the selfexcitation will be uniformly felt throughout the slice chamber and will not materially effect the small scale turbulence which remains in the stock flow due to its turbulence within the headbox and will not cause secondary'flow patterns to deteriorate the flow stream.
  • the excitation will occur at the natural frequency of the rods which can be expressed by the conventional formula f V k/m where k is the spring constant and m is the mass of the rod members. While the preferred form embodies individual rods self-supporting sheets or plates will also work. These plates can be of substan tially narrow width, which is preferred, or can be of increasing wider width to the degree where they extend completely across the slice.
  • the structure for providing the cantilever support for the rod members 20 is shown as a plate 18 having openings 19 therethrough for admitting the flow of stock.
  • the openings are shown in the form of circular holes which are generally uniformly distributed across the plate.
  • the Holes are arranged in upper and lower rows, and while the rod members are substantially randomly distributed across the slice this random distribution is achieved by an organized arrangement of the rods relative to the holes.
  • rods 20 may be each of uniform size, in a preferred arrangement as shown, the rods centrally spaced between the upper and lower walls 27 and 28, are larger and the successive rods spaced outwardly toward the walls are of increasing size.
  • the central rods 21 are also longer than the joining rods proceeding towards the upper and lower walls of the slice chamber 17.
  • the length of the rods is chosen so that they do not engage the surfaces of the walls 27 or 28, and there is an increasing space between the ends of the rods and the walls in a downstream direction.
  • the rods are preferably of uniform thickness throughout each of their lengths. However, they may also be shaped and may be round, flat, curved or spiralled. However, a preferred shape is shown in FIG. 4.
  • the central rods 21, FIG. 2, are arranged in a row extending horizontally across the center of the plate 18.
  • the remainder of the rods are arranged with their centers positioned on circles swung from the centers of each of the holes 19.
  • the largest rods of the groups surrounding each of the holes 19 are positioned closest to the center of the slice chamber 17.
  • the rods 22 are the largest of each of the groups positioned around the holes 19 and are placed slidably above and below the center row of rods 21.
  • the next largest group of rods is shown at 23 positioned outwardly from the rods 22.
  • the next largest is 24, and these are positioned outwardly from the rods 23.
  • the remaining rods 25 and 26 are for convenience of the same size as the rods 24.
  • FIG. 4 illustrates a preferred form of rod 20 which is cantileverally supported on the wall 18.
  • Flow holes 34 surround the rod with the direction of flow being shown by the arrows 33.
  • the rod functions in operation as a vibrating member, and for enhancing this motion, it is provided with an enlarged or bulbous end 32.
  • a pressure wave or sonic field is generated in the liquid paper stock by the rod 20' whose vibration is excited by the flow of the suspension passing them.
  • the vibration of the element is excited by the separation of the flow by the flared tip 32.
  • the vibratory movement of the members 20 enhance dispersion as above stated.
  • the rods must be sufficiently long with respect to their diameter to obtain the self-excitation and must not be so long as to be self-supporting.
  • An example of a small slice arrangement constructed in accordance with the invention is as follows:
  • Rods 24 thru 26 Angular spacing between rods 3/ l 6' diameter 22 thru 26: 45 Distance between rods 21: l" Distance between openings 18: 1%" Length of rods 2!: 21'. Length of rods 22 18" Length of rods 23: 14"
  • Length of rods 24 Length of rods 25 and 26:
  • a headbox structure for feeding a slurry of stock onto a traveling forming surface
  • the combination comprising, means defining a slice chamber having an entry end leading to the chamber and a discharge slice opening for conducting a stock formed of a dispersion of fibers in a liquid carrier onto a traveling forming surface, a stock headbox supply connected to the entry under the slice for delivering the stock uniformly across the width of the slice chamber, a plurality of separate selfexciting thin elongate vibrational members extending downstream in the slice chamber in the direction of flow and cantilever supported at their upper ends having sufficient rigidity so that their general position is independent of stock flow to be self-supporting along their entire length so that the members vibrate with the flow of stock through the slice chamber and reduce the network strength between the stock fibers, and support means in the slice chamber forming a cantilever support for the upstream ends of each of said members.
  • a headbox structure for feeding a slurry of stock onto a traveling forming surface constructed in accordance with claim 1, the combination wherein said support means is in the form of aplate extending across the entry end of the slice chamber and a plurality of flow openings are provided through said plate for the flow of stock from the headbox to the slice chamber.
  • a headbox structure for feeding a slurry of stock onto a traveling forming surface constructed in accordance with claim 4, the combination wherein certain of said members are arranged in an annular pattern each around said openings on the plate and the openings are substantially circular.
  • a headbox structure for feeding a slurry of stock onto a traveling forming surface constructed in accordance with claim 8, the combination wherein the length of the members is such that the distance from the tips of different members to the upper and lower walls of the slice decreases in a downstream direction.
  • the method of reducing the network strength between fibers in a stock slurry of dispersed fibers in a liquid carrier being fed from a headbox onto a traveling forming surface through a slice chamber which comprises positioning a plurality of thin self-supporting, self-exciting vibrational members having sufficient rigidity so that their general position is independent of stock flow and being self-supporting along their entire length in the slice chamber immediately ahead of the slice opening, and supporting them cantileverly at their upstream ends to extend substantially parallel to the flow in a downstream direction so that they vibrate and reduce said network strength.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
  • Nonwoven Fabrics (AREA)
US00126176A 1971-03-19 1971-03-19 Papermaking machine headbox with multiple stiff, vibrational rods or plates extending downstream in the slice chamber Expired - Lifetime US3769153A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US12617671A 1971-03-19 1971-03-19

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US3769153A true US3769153A (en) 1973-10-30

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US (1) US3769153A (it)
JP (1) JPS5037281B1 (it)
CA (1) CA945794A (it)
ES (1) ES400648A1 (it)
GB (1) GB1357455A (it)
IT (1) IT950351B (it)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
US3853694A (en) * 1973-04-24 1974-12-10 Beloit Corp Paper machine flow channel with a flexible plate projecting into the flow stream to act as an oscillator
DE3723922A1 (de) * 1987-07-18 1989-01-26 Bruderhaus Maschf Neue Turbulenzerzeuger fuer den stoffauflauf einer papiermaschine
US5019215A (en) * 1988-10-17 1991-05-28 Groupe Laperrier & Verreault, Inc. Headbox with conduits having multiply connected domains

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6288751A (ja) * 1985-10-14 1987-04-23 Nissei Birudo Kogyo Kk パネル材の反転装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3220919A (en) * 1962-10-05 1965-11-30 Beloit Corp Shaped rod turbulence generators for use in a flowing stream of paper pulp
US3236725A (en) * 1963-02-09 1966-02-22 Dominion Eng Works Ltd Adjustable baffle for paper stock inlet
US3607625A (en) * 1968-01-17 1971-09-21 Beloit Corp Headbox

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3220919A (en) * 1962-10-05 1965-11-30 Beloit Corp Shaped rod turbulence generators for use in a flowing stream of paper pulp
US3236725A (en) * 1963-02-09 1966-02-22 Dominion Eng Works Ltd Adjustable baffle for paper stock inlet
US3607625A (en) * 1968-01-17 1971-09-21 Beloit Corp Headbox

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
US3853694A (en) * 1973-04-24 1974-12-10 Beloit Corp Paper machine flow channel with a flexible plate projecting into the flow stream to act as an oscillator
DE3723922A1 (de) * 1987-07-18 1989-01-26 Bruderhaus Maschf Neue Turbulenzerzeuger fuer den stoffauflauf einer papiermaschine
US5019215A (en) * 1988-10-17 1991-05-28 Groupe Laperrier & Verreault, Inc. Headbox with conduits having multiply connected domains

Also Published As

Publication number Publication date
IT950351B (it) 1973-06-20
JPS5037281B1 (it) 1975-12-01
GB1357455A (en) 1974-06-19
CA945794A (en) 1974-04-23
ES400648A1 (es) 1975-08-16

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