US3617443A - Gravity drainage from a rotor in a centrifugal fibrous sheet former - Google Patents

Gravity drainage from a rotor in a centrifugal fibrous sheet former Download PDF

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Publication number
US3617443A
US3617443A US880242A US3617443DA US3617443A US 3617443 A US3617443 A US 3617443A US 880242 A US880242 A US 880242A US 3617443D A US3617443D A US 3617443DA US 3617443 A US3617443 A US 3617443A
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United States
Prior art keywords
rotor
shell
liquid
centrifugal
sheet
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Expired - Lifetime
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US880242A
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English (en)
Inventor
Jean-Pierre Chleq
Gaston Marie Lefebvre
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CENTRE TECH IND PAPIER
CENTRE TECHNIQUE DE L'INDUSTRIE DES PAPIERS
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CENTRE TECH IND PAPIER
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Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B11/00—Feeding, charging, or discharging bowls
    • B04B11/04—Periodical feeding or discharging; Control arrangements therefor
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D5/00—Purification of the pulp suspension by mechanical means; Apparatus therefor
    • D21D5/02—Straining or screening the pulp
    • D21D5/06—Rotary screen-drums

Definitions

  • a method for removing the filter means with the formed sheet thereon is provided wherein the screen is cut and deformed to allow removal from an opening in the cover of the apparatus.
  • SHEET 1 [IF 2 PATENTEU HUV2 lsn SHEET 2 OF 2 GRAVITY DRAINAGE FROM A ROTOR IN A CENTRIFUGAL FIBROUS SHEET FORMER
  • the invention relates to a method for evacuating a fluid contained in a centrifugal former for forming a sheet of fibrous material (for example, paper) after this sheet has been formed.
  • centrifugal former means a machine intended to form sheets of fibrous material, such as paper, more particularly in laboratories, wherein this former consists substantially of an external, fixed, stator inside which a rotor may be rotatively driven.
  • This rotor comprises:
  • a fibrous suspension for example, paper pulp
  • centrifugal formers of known construction may be divided into three operating phases.
  • the liquid is introduced into the rotor while the same rotates. Under the action of the centrifugal force, the liquid is applied to the outer envelope of the rotor and forms a wall which submerges the filtering wall of the rotor. Then,'the fibrous suspension is injected by a nozzle which may form part of an oscillating device in order to achieve the regular distribution of the suspension over the inside of the filtering wall. The fibrous suspension settles against the fluid screen on the filtering wall and is uniformly deposited on this wall. Excess liquid is eliminated, either by means of a suction device," or by an excess centrifuging system.
  • the supply is stopped and the fluid is progressively evacuated from the rotor by a suction device, drawing off the liquid from the center of the liquid "wall.”
  • the rotor is stopped and the filtering wall with the formed sheet is withdrawn.
  • This extraction can be made from the top of the former by removing the top cover.
  • the sheet may also be withdrawn with the filtering wall through an opening in this cover, by providing a deformable filtering wall which enables it to pass through this orifice.
  • the invention has the object of eliminating these drawbacks by means of an evacuating method which uses no suction oevice.
  • this method the removal of liquid is determined by slowing down the rotor which gives rise to a progressive reduction of the centrifugal force and is effected under the action of the force of gravity by suitable means provided at the lower end of the rotor.
  • the forces of gravity acting on the liquid increase relative to the decreasing centrifugal forces and give rise to the drainage of the liquid.
  • This method does not require the provision of an asperation suction device and removes from the user the burden of having to start and control an evacuating device. Moreover. there occurs no throwing off of liquid which might alter the fibrous structure sheet.
  • the progressive slowing down of the rotor makes it possible to maintain at the tangential speeds of the flow of the liquid lower values than those which would cause an alteration of the sheet under the effects of shearing action.
  • the invention also relates to an extraction method for withdrawing a sheet of fibrous structure after its formation from the rotor of the former.
  • the other method which consists of withdrawing without dismantling the sheet through an opening in the cover by deforming the filtering wall has proved to be a rather delicate operation in known formers.
  • centrifugal formers the construction of which is based on traditional centrifuges, the base of the rotor has the shape of an inverted bowl in which the end of the drive shaft is engaged and fixed. This construction impedes substantially the extraction of the filtering wall and prevents the user from deforming the same in such a manner as to prevent its deterioration from the point of view of a reutilization of this wall.
  • auxiliary flexible filtering support for example, a metal sheet
  • This method makes possible the easy and quick extraction of the sheet on its flexible support. Since the deformations of the support are not permanent the same can be used again after the sheet has been detached from its surface.
  • the operation of cutting the sheet of paper along one of its generatrices may conveniently be effected by pulling apart the originally abutting edges of the auxiliary support.
  • the temporary deformation of the auxiliary support consists in lightly rolling up this support on itself.
  • the invention also relates to the rotor of a centrifugal former adapted to apply the method hereinbefore described.
  • the rotor has a flat base which is butt-mounted on a drive shaft.
  • This construction which differs from the construction of conventional rotors with bases in the shape of an inverted bowl, permits the easy and quick extraction of the sheet of paper after it has been formed by the method described above.
  • the base of the rotor contains conduits leading between the filtering wall and the outer cylindrical shell. These conduits have the object of removing the liquid in the rotor after the formation of the sheet.
  • the outer cylindrical shell may be provided with a lower lip turned towards the axis of the rotor and located near and above the base of the rotor and a similar upper lip located near the upper edge of the shell.
  • the weakening of the centrifugal force determines the discharge of liquid over the edge of the lower lip.
  • the radial depth of the upper and lower lips is preferably equal to the ideal thickness of the wall" of liquid desired during the rotation of the rotor.
  • the wall of liquid which forms during the rotation has. therefore, an optimum thickness for the formation of the sheet with fibrous structure.
  • Braking means may be provided for the progressive slowing down of the rotor in order to ensure tangential speeds for the discharge of the liquid at lower values than those which would produce a change in the sheet under shearing action.
  • FIG. 1 is an axial cross section of a centrifugal former according to the invention
  • FIGS. 2a, 2b, 2c diagrams showing a former in three stages of emptying for three different speeds of the rotor
  • FIGS. 30 and 3c are views in perspective of a former, showing respectively the grid fitted on the inside and during its extraction;
  • FIG. 3b is a detail showing the edges of the grid during their pulling apart.
  • a centrifugal former (FIG. 1) consists of a fixed stator l on a support 2 and a rotor comprising a tight cylindrical shell 3 and a filtering wall 4 located between an annular top cover or lip 5 and a flat base 6.
  • This rotor is mounted tightly on the end of a shaft 7 mounted conventionally in a roller bearing 8.
  • the shaft is adapted to be rotated by a motor 9 and a belt 10.
  • Reference numerals I1 and 12 indicate diagrammatically a starting device and a progressive braking device for example, a friction brake arrangement.
  • the filtering wall 4 is covered by a grid 13 retained between two annular covers 14 and 15 fixed on the filtering wall 4 and adapted to be mounted at varying heights.
  • the tight base 6 contains conduits such as 16 which lead into the space between the shell 3 and the filtering wall 4.
  • annular lip 17 retained by screws on a circular flange l8, cooperates with the upper cover 5 of equal radial depth during the rotation of the. rotor in order to permit the formation of a wall of water on the shell 3 by centrifugal action.
  • the thickness of this wall is between the radial thickness of the lip 17 and the radial thickness of the cover 5 wherein the surplus of liquid is removed by centrifuging over the edges of this lip 17.
  • the lips extend the same distance beyond the filtering wall in a direction towards an axis of the rotor and shell as determined by the shaft 7.
  • the stator 1 has a base 19, through which passes an evacuation conduit 20.
  • a nozzle 21, adapted to be driven by a reciprocating device, not shown, can inject regularly a fibrous suspension, for example paper paste, on the grid 13.
  • the rotor is actuated in rotation and reaches its normal rotational speed. This speed is such that the linear velocity of the filtering wall is between about 600 and 1,800 meters a minute.
  • a fluid for example water
  • a fluid for example water
  • the centrifugal force which is great relative to the force of gravity
  • the shell 3 and forms a wall of water 22 (FIG. 2a).
  • the inner surface of this wall of water 22 has a substantially cylindrical shape.
  • a fibrous suspension for example, a paper paste
  • the suspension submerges into the film of liquid covering the grid 13 applied against the filtering wall 4 and is deposited on this grid.
  • the excess water flows off over the edges of the lower lip 17 and off the upper cover 5.
  • the progressive braking device 12 is brought into action.
  • the grid 13 is slightly rolled up on itself (FIG. 3c) enabling it to be extracted from the former.
  • the sheet 25 is then detached from the grid 13 which can be'placed again into the former for further use.
  • the grid 13 may have zones of different nature or dimensions, for producing a sheet with certain structural particularities (for example, filigrane).
  • a method for forming a fibrous sheet in the rotor of a centrifugal former equipped with a cylindrical filtering wall comprising:
  • a method as claimed in claim I wherein temporary deformation of the support consists in slightly rolling up the support on itself.
  • a method for draining a liquid contained in a rotor of a centrifugal former in which a fibrous sheet is formed the rotor including a cylindrical outer envelope and a cylindrical inner filtering means, the rotor being vertically oriented, the steps comprising: rotating said rotor to maintain the liquid against said outer envelope by centrifugal force while simultaneously forming a fibrous sheet on the inside of said filtering means,
  • a rotor for a centrifugal former comprising:
  • a cylindrical outer shell a perforated base connected to said cylindrical outer shell and connected to a drive shaft which rotates the rotor along the axis of the cylindrical outer shell, annular lips connected to said cylindrical outer shell, said lips extending from the upper and lower ends of said shell towards said axis of said shell, the said lower lip being connected to said shell at a point below said perforated base, a cylindrical filtering wall arranged inside said shell between said upper lip and said perforated base being concentric to said shell, said lips extending the same distance beyond said filtering wall in a direction towards said axis of said shell, said rotor also including;

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Centrifugal Separators (AREA)
  • Paper (AREA)
US880242A 1968-11-29 1969-11-26 Gravity drainage from a rotor in a centrifugal fibrous sheet former Expired - Lifetime US3617443A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR176066 1968-11-29

Publications (1)

Publication Number Publication Date
US3617443A true US3617443A (en) 1971-11-02

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ID=8657655

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Application Number Title Priority Date Filing Date
US880242A Expired - Lifetime US3617443A (en) 1968-11-29 1969-11-26 Gravity drainage from a rotor in a centrifugal fibrous sheet former

Country Status (6)

Country Link
US (1) US3617443A (de)
DE (2) DE1959465B2 (de)
FR (1) FR1597653A (de)
GB (1) GB1260876A (de)
NL (1) NL6917859A (de)
SE (1) SE369613B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3723244A (en) * 1971-01-18 1973-03-27 Atomic Energy Commission Fibrous fibrin sheet and method for producing same
US4239626A (en) * 1979-02-21 1980-12-16 Niagara Bottle Washer Manufacturing Co. Filter for removing fines
DE102004059268A1 (de) * 2004-12-08 2006-06-29 Frormann, Lars, Prof. Dr.-Ing. Verfahren zur Verarbeitung von gefüllten auch fasergefüllten Suspensionen mittels Rotationsformen insbesondere zur Herstellung rotationssymmetrischer bindenahtfreier Hohlkörper aus Papier bzw. Faserstoffen beliebiger Durchmesser

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1142737A (fr) * 1956-02-17 1957-09-20 Centrifugeuse-filtre à vidange
US3210241A (en) * 1962-05-16 1965-10-05 G Grauss Ets Method and device for manufacturing laboratory articles such as samples of paper sheets

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1142737A (fr) * 1956-02-17 1957-09-20 Centrifugeuse-filtre à vidange
US3210241A (en) * 1962-05-16 1965-10-05 G Grauss Ets Method and device for manufacturing laboratory articles such as samples of paper sheets

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3723244A (en) * 1971-01-18 1973-03-27 Atomic Energy Commission Fibrous fibrin sheet and method for producing same
US4239626A (en) * 1979-02-21 1980-12-16 Niagara Bottle Washer Manufacturing Co. Filter for removing fines
DE102004059268A1 (de) * 2004-12-08 2006-06-29 Frormann, Lars, Prof. Dr.-Ing. Verfahren zur Verarbeitung von gefüllten auch fasergefüllten Suspensionen mittels Rotationsformen insbesondere zur Herstellung rotationssymmetrischer bindenahtfreier Hohlkörper aus Papier bzw. Faserstoffen beliebiger Durchmesser

Also Published As

Publication number Publication date
GB1260876A (en) 1972-01-19
FR1597653A (de) 1970-06-29
DE1959465B2 (de) 1973-10-18
NL6917859A (de) 1970-06-02
SE369613B (de) 1974-09-09
DE1966553A1 (de) 1973-07-05
DE1959465A1 (de) 1970-06-25

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