US3769154A - Pressurized chambers for controlling deflection of papermaking machine headbox walls - Google Patents

Pressurized chambers for controlling deflection of papermaking machine headbox walls Download PDF

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Publication number
US3769154A
US3769154A US00094517A US3769154DA US3769154A US 3769154 A US3769154 A US 3769154A US 00094517 A US00094517 A US 00094517A US 3769154D A US3769154D A US 3769154DA US 3769154 A US3769154 A US 3769154A
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US
United States
Prior art keywords
wall
inlet box
stock inlet
girder
load relief
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
US00094517A
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English (en)
Inventor
K Wolf
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JM Voith GmbH
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JM Voith GmbH
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Filing date
Publication date
Priority claimed from DE19691962634 external-priority patent/DE1962634C/de
Application filed by JM Voith GmbH filed Critical JM Voith GmbH
Application granted granted Critical
Publication of US3769154A publication Critical patent/US3769154A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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

  • the invention relates to a closed and pressure operated stock inlet box, in particular for paper making machines, and having a discharge nozzle extending over the machine width, the nozzle being defined by an upper and lower lip each of which is supported by one wall of the stock inlet box, and each said wall being formed as a hollow girder.
  • the walls of the stock inlet box of the machine are subjected to ever increasing loadings, namely, and in particular, due to the pressure prevailing in the interior of the box.
  • the pressure in a stock inlet box increases, as is known, with the velocity with which the stock jet is discharged from the said discharge nozzle of the stock inlet box.
  • the loading due to the dead weight of the stock inlet box is also substantial in the case of large machine widths.
  • a known stock inlet box (German Pat. No. 1,461,176 is provided with a load relief girder on the outside of each lip supporting wall, constructed as a cavity girder, and being adapted to support the respective wall against deflection due to internal pressure by means of a pressure chamber, extending substantially over the entire machine width and supplied with a pressure medium. While the above mentioned load relief girder flexes freely due to the internal pressure transmitted from the pressure chamber, the lip supporting wall itself is not stressed at all in bending, in the ideal case when the loading is equal on both sides thereof.
  • each lip supporting wall must have a substantial section modulus and must be correspondingly dimensioned.
  • each lip supporting wall of the above mentioned known stock inlet box is constructed as a hollow girder the side of which facing the inside of the stock inlet box is biased by the internal pressure of the stock inlet box and the side of which facing the exterior bears against the pressure chamber and is biased by the chamber pressure. Accordingly, seen from the side towards the stock inlet box, the cross section of each wall has a certain minimum extension.
  • the load relief girder also has cross-sectional dimensions which are not insubstantial. Accordingly, a structural unit of the kind heretofore described and comprising a wall and load relief girder occupies a comparatively large amount of space, which leads to difficulties if the required space is not available.
  • a primary objective of the present invention is the provision of a stock inlet box of the nature referred to in which at least one of the walls of the box supporting a lip of the nozzle of the box is supported against deflection but without greatly increasing the cross sectional dimensions of the supported wall.
  • Another object of the present invention is the provision of a supporting arrangement for a wall of a stock inlet box which supports a lip of the nozzle of the box in which the supporting arrangement is located substantially completely within the normal cross sectional confines of the supported portion of the wall.
  • Still another object is the provision of a supporting arrangement for a wall of a stock inlet box which supports a lip of the nozzle of the box in which the supporting arrangement employs a pressure medium for effecting the support but wherein loss of pressure of the medium does not result in complete loss of the supporting function of the supporting arrangement.
  • FIG. 1 shows a stock inlet box for a high speed papermaking machine shown in longitudinal section along the longitudinal axis of the machine.
  • FIG. 2 is a section taken along the line II--II of FIG. 1 and drawn at enlarged scale and showing a supporting structure comprising hollow girder, load relief girder and pressure chamber.
  • FIG. 3 is a fragmentary view like FIG. 2, but shows a modified form wherein the hollow girder is open at the ends.
  • the problem is solved in that the load relief girder and the pressure chamber associated therewith are disposed within the wall which is constructed as hollow girder.
  • the load relief girder is thus completely surrounded by the stock inlet box wall which is constructed as a hollow girder so that the space requirements of a stock inlet box constructed in accordance with the invention and, as seen from the side, is no greater than that of a conventional stock inlet box which has no load relief girder and no pressure chamber.
  • hollow girder forming the affected wall of the stock inlet box is constructed in totally enclosed form or if it has apertures on the end faces and/or on the side opposite to the interior of the stock inlet box.
  • a hollow girder which is open at the end faces will be used in a preferred embodiment since it is then very simple to install the load relief girder.
  • the hollow girder forming the wall of the stock inlet box may, however, also be comprises of a plate, facing the interior of the box, and of two stiffening members disposed in longitudinally spaced relation on the exterior of the plate and between which the load relief girder is accommodated.
  • the idea of the invention may be applied to the front wall which supports the upper lip of the nozzle as well as to the wall supporting the lower lip of the nozzle and forming the bottom wall of the stock inlet box.
  • the stock inlet box is shortened, over prior art constructions, in the direction corresponding to the longitudinal machine orientation while, in the other case, a corresponding reduction is obtained in the structural height of the stock inlet box. It is, of course, possible for both the front wall and the bottom wall of the stock box to be constructed in accordance with the invention.
  • the manner in which the load relief girder is mounted in the appropriate hollow wall girder of the respective wall of the stock inlet box is of no consequence for the method of operation of the entire supporting structure provided the mounting of the load relief girder is located exclusively in the region of the load relief girder ends, in order to ensure completely free flexure of said load relief girder.
  • the ends of the load relief girder may be welded directly to the end faces of the hollow girder, for example to end flanges which are common to the hollow girder and the load relief girder.
  • such construction causes the welding seams to be simultaneously stressed in tension and bending and, therefore, result in a relatively unfavorable form of loading.
  • connection between the hollow girder of the wall of the stock inlet box and the load relief girder associated therewith be provided exclusively by tie elements disposed at the ends of the load relief girder.
  • tie elements may, for example, be relatively thin plates which therefore have flexural elasticity and which do not offer any substantial resistance to the bending moment developed thereon which occurs when the load relief girder is formed. Welded joints, in such an arrangement, are, in practice, stressed only in tension.
  • spacers In the event that the pressure in the pressure chamber collapses during operation of the papermaking machine it is advantageous for spacers to be disposed within the pressure chamber between the lip supporting wall of the stock inlet box and the load relief girder pertaining thereto, the height of said spacers being preferable identical to the internal width of the pressure chamber when the wall of the stock inlet box is in the unpressurized state on both sides of the wall. Accordingly in the previously mentioned emergency, namely, when there is a loss of pressure in the pressure chamber, it is possible for the affected wall of the stock inlet box to bear directly on and be supported by the load relief girder. In such a case, the section moduli of the wall of the stock inlet box and of the load relief girder will be additive so that the flexure of the wall of the stock inlet box remains within tolerable limits.
  • the stock inlet box of FIG. I is provided with a front wall I and a bottom wall 2, both constructed in accordance with the invention, also a stiffened rear wall 3, lateral walls indicated by 30, a cover 4, a traversing transmission 5 for the vertical adjustment of the front wall I, and an inlet chamber 6.
  • a discharge nozzle 20, extending over the entire width of the stock inlet box and having a lower lip 21 and an upper lip 22 is formed from the front wall 1 and the bottom wall 2.
  • Perforated rollers 7 and an overflow trough 9 are also provided in the interior of the box.
  • the front wall 1 is constructed as a hollow girder which completely surrounds a load relief girder 10.
  • a pressure chamber 12 extending over the entire width of the stock inlet box and having a connection, not shown, for a pressure medium, for example, water is confined between the said load relief girder 10 and that part of the front wall 1 which faces the: interior of the stock inlet box.
  • the internal pressure in the stock inlet box bears on the internal surface of the front wall 1 and is transmitted via the pressure medium in the pressure chamber 12 to the load relief girder 10.
  • the surface offered by the front wall 1 to the internal pressure is, of course, somewhat larger than that part of the front wall which is biased by the chamber pressure.
  • the pressure in the pressure chamber 12 can be adjusted to a value exceeding the internal pressure in the stock inlet box, that part of the front wall 1 which faces the interior of the stock inlet box, and therefore the upper lip 22 of the discharge nozzle are practically free of flexure; only the load relief girder 10 is deformed.
  • the stock inlet box wall supporting the lower lip 21, namely, the bottom wall 2 is constructed in the same manner as the front wall 1 in the form of hollow girder means.
  • Two hollow girders 30 and 31 of box-shaped cross section are fixed to the underside of bottom wall 2, each said hollow girder surrounding one load relief girder 32.
  • a pressure chamber 34 is provided between each load relief girder and the respective hollow girder, each chamber being supplied by a pressurized medium from means 34a.
  • the connection between the bottom wall 2, constructed as hollow girder, and the load relief girder 32 associated therewith, is formed by two tie elements 36 and 37. These are provided at both ends of the entire supporting structure and are constructed as flexurally elastic but inextensible plates.
  • Spacers 38 and 39 are disposed within the pressure chamber 34 on the said bottom wall 2. In the event of loss of pressure in the pressure chamber it is, therefore, possible for the said spacers directly to support the bottom wall 2 on the load relief girder 32.
  • Two of the aforementioned spacers 38 extend along the fore and aft edges of each load relief girder, parallel to.
  • the hollow girder forming the front wall 10 is provided in a like manner with spacers and sealing strips. However, these are not provided with reference symbols in the drawing.
  • the hollow girder 30 illustrated in FIG. 2 is enclosed all round, that is to say it is also enclosed at its end faces.
  • the hollow girder 30a, illustrated in FIG. 3 differs therefrom in that its end faces are constructed in open form in order to simplify the installation of the load relief girder.
  • the pressure chamber disposed between the upper side of the load relief girder 32 in FIG. 3 and the underside of bottom wall 2 of the stock inlet box is, of course, sealed on all sides to permit pressure to be developed therein.
  • a closed and pressure operated stock inlet box especially for a papermaking machine, and having confining front, rear, and bottom walls and a laterally extending discharge nozzle, said nozzle comprising upper and lower lips, the upper lip of said nozzle extending from and supported by said front wall of said stock inlet box, and said lower lip extending from and supported by said bottom wall
  • hollow girder means extending transversely of the stock inlet box and connected to said lip supporting walls on the sides of said walls which face away from said stock inlet box from imparting stiffness to said lip supporting walls, at least one transversely extending load relief girder means disposed inside a respective hollow girder means and substantially coextensive therewith in the longitudinal direction, connecting means connected between the periphery of said load relief girder means and the respective said wall and confining a closed pressure chamber between the respective lip supporting wall and the side of the relief girder means facing the said wall, said connecting means permitting said relief girder means to flex relative to the respective said wall in the region of said
  • a stock inlet box according to claim 1 in which the connection of the ends of said load relief girder means to said hollow girder means comprises flexible inextensible elements.
  • a stock inlet box according to claim 2 in which said flexible elements seal said pressure chamber at the ends, and seal members along the sides of said chamber which are elongatable so as not to interfere with flexing of the respective said load relief girder means.
  • a stock inlet box according to claim 1 in which said hollow girder means are open at at least the ends thereof.
  • a stock inlet box which includes spacer means disposed in said chamber between the respective lip supporting wall and the side of the load relief girder means facing the wall and free of at least one thereof and operable for transmitting loads from the said wall to the load relief girder means in the absence of pressure in said pressure chamber.
  • a stock inlet box according to claim 4 in which said spacer means are distributed in said pressure chamber and are dimensioned so as to engage both the said wall and the said load relief girder means when the said wall is free of pressure on both sides thereof.
  • a stock inlet box according to claim 1 which includes at least one said load relief girder means inside the hollow girder means for each of said lip supporting walls of the stock inlet box.
  • a stock inlet box accordng to claim 1 in which the stock inlet box wall supporting the lower lip of the nozzle forms the lower wall of the stock inlet box, said hollow girder means for said lower wall comprising a pair of hollow girders spaced longitudinally along the lower wall, and a said load relief girder means inside each said hollow girder of said lower wall.

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  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
  • Preliminary Treatment Of Fibers (AREA)
US00094517A 1969-12-13 1970-12-02 Pressurized chambers for controlling deflection of papermaking machine headbox walls Expired - Lifetime US3769154A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691962634 DE1962634C (de) 1969-12-13 Geschlossener und unter Innendruck stehender Stoffauflaufkasten

Publications (1)

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US3769154A true US3769154A (en) 1973-10-30

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US (1) US3769154A (fi)
JP (1) JPS4932723B1 (fi)
AT (1) AT305752B (fi)
BE (1) BE759413A (fi)
CA (1) CA935000A (fi)
CS (1) CS148144B2 (fi)
FI (1) FI49857C (fi)
GB (1) GB1311708A (fi)
NO (1) NO137100C (fi)
PL (1) PL81388B1 (fi)
RO (1) RO56483A (fi)
SE (1) SE367029B (fi)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3977938A (en) * 1973-05-21 1976-08-31 Dominion Engineering Works, Limited Support beam for the rectifier section of a headbox
US4008123A (en) * 1974-07-08 1977-02-15 Valmet Oy Beam-deflection compensating structure for headboxes
DE3533072A1 (de) * 1985-07-12 1987-01-22 Escher Wyss Gmbh Stoffauflauf-vorrichtung fuer eine papiermaschine
US4675077A (en) * 1986-06-20 1987-06-23 Sandy Hill Corporation Adjustable means for profile correction for a headbox slice
US4770745A (en) * 1985-11-19 1988-09-13 Sulzer-Escher Wyss Gmbh Front wall and support arrangement at the headbox of a papermaking machine
US4832794A (en) * 1986-08-26 1989-05-23 Valmet Oy Method and apparatus for compensating deflection of a lip beam in a paper machine
US4980026A (en) * 1988-10-22 1990-12-25 J. M. Voith Gmbh Headbox with movable duct wall
US5164048A (en) * 1990-08-29 1992-11-17 Measurex Corporation Cooling structure for stabilizing the temperature of beams in a sheet-making apparatus

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2928464A (en) * 1957-01-01 1960-03-15 Albert E Reed And Company Ltd Adjustable slice for flow box
US3313681A (en) * 1964-08-27 1967-04-11 Beloit Corp Headbox with bottom wall having controllable deflection
US3468756A (en) * 1965-04-08 1969-09-23 Valmet Oy Paper machine head box support
DE1461176A1 (de) * 1965-06-04 1969-10-09 Voith Gmbh J M Stoffauflauf mit geschlossenem Auflaufkasten,insbesondere fuer Papiermaschinen
US3556935A (en) * 1968-04-03 1971-01-19 Procter & Gamble Papermaking headbox with adjustable hydraulic nozzle and slice
US3562106A (en) * 1970-02-02 1971-02-09 Beloit Corp Apparatus for maintaining the slice opening in a papermaking headbox

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2928464A (en) * 1957-01-01 1960-03-15 Albert E Reed And Company Ltd Adjustable slice for flow box
US3313681A (en) * 1964-08-27 1967-04-11 Beloit Corp Headbox with bottom wall having controllable deflection
US3468756A (en) * 1965-04-08 1969-09-23 Valmet Oy Paper machine head box support
DE1461176A1 (de) * 1965-06-04 1969-10-09 Voith Gmbh J M Stoffauflauf mit geschlossenem Auflaufkasten,insbesondere fuer Papiermaschinen
US3556935A (en) * 1968-04-03 1971-01-19 Procter & Gamble Papermaking headbox with adjustable hydraulic nozzle and slice
US3562106A (en) * 1970-02-02 1971-02-09 Beloit Corp Apparatus for maintaining the slice opening in a papermaking headbox

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3977938A (en) * 1973-05-21 1976-08-31 Dominion Engineering Works, Limited Support beam for the rectifier section of a headbox
US4008123A (en) * 1974-07-08 1977-02-15 Valmet Oy Beam-deflection compensating structure for headboxes
DE3533072A1 (de) * 1985-07-12 1987-01-22 Escher Wyss Gmbh Stoffauflauf-vorrichtung fuer eine papiermaschine
US4906336A (en) * 1985-07-12 1990-03-06 Sulzer-Escher Wyss Gmbh Headbox device for a papermaking machine
US4770745A (en) * 1985-11-19 1988-09-13 Sulzer-Escher Wyss Gmbh Front wall and support arrangement at the headbox of a papermaking machine
US4675077A (en) * 1986-06-20 1987-06-23 Sandy Hill Corporation Adjustable means for profile correction for a headbox slice
US4832794A (en) * 1986-08-26 1989-05-23 Valmet Oy Method and apparatus for compensating deflection of a lip beam in a paper machine
US4980026A (en) * 1988-10-22 1990-12-25 J. M. Voith Gmbh Headbox with movable duct wall
US5164048A (en) * 1990-08-29 1992-11-17 Measurex Corporation Cooling structure for stabilizing the temperature of beams in a sheet-making apparatus

Also Published As

Publication number Publication date
SE367029B (fi) 1974-05-13
RO56483A (fi) 1974-07-01
PL81388B1 (fi) 1975-08-30
FI49857C (fi) 1975-10-10
JPS4932723B1 (fi) 1974-09-02
NO137100B (no) 1977-09-19
GB1311708A (en) 1973-03-28
FI49857B (fi) 1975-06-30
CA935000A (en) 1973-10-09
NO137100C (no) 1977-12-28
BE759413A (fr) 1971-04-30
CS148144B2 (fi) 1973-02-22
AT305752B (de) 1973-03-12

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