EP0398685A1 - Procédé et dispositif pour le traitement d'une suspension de fibres - Google Patents

Procédé et dispositif pour le traitement d'une suspension de fibres Download PDF

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Publication number
EP0398685A1
EP0398685A1 EP90305288A EP90305288A EP0398685A1 EP 0398685 A1 EP0398685 A1 EP 0398685A1 EP 90305288 A EP90305288 A EP 90305288A EP 90305288 A EP90305288 A EP 90305288A EP 0398685 A1 EP0398685 A1 EP 0398685A1
Authority
EP
European Patent Office
Prior art keywords
filter
accordance
counter
suspension
fraction
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.)
Withdrawn
Application number
EP90305288A
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German (de)
English (en)
Inventor
Risto Ljokkoi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ahlstrom Corp
Original Assignee
Ahlstrom Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Ahlstrom Corp filed Critical Ahlstrom Corp
Publication of EP0398685A1 publication Critical patent/EP0398685A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • D21D5/023—Stationary screen-drums
    • D21D5/026—Stationary screen-drums with rotating cleaning foils
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
    • B07B1/18—Drum screens
    • B07B1/20—Stationary drums with moving interior agitators

Definitions

  • the present invention relates to a method and an apparatus for treating fiber suspension.
  • the method in accordance with the invention is especially suitable for screening pulps of the pulp and paper industry and also for thickening.
  • the apparatus part of the invention relates to a rotor construction of a power screen or a thickener.
  • An example of the second type is, for example, an arrangement in accordance with US patent specification 3437204, in which the rotor is a substantially cylindrical, closed piece, the surface of which has almost hemispherical protrusions.
  • the pulp in this type of apparatus is introduced to the treating space between the rotor cylinder and the filter cylinder outside the rotor cylinder, whereby the purpose of the rotor protrusions, so called bumps, is both to press the pulp against the filter cylinder and to draw the matted pulp with the trailing edge from the openings of the filter cylinder.
  • German application 3006482 disclose a knotter, which has on the surface of a cylindrical rotor drum plough-shaped protrusions made of plate material, the purpose of which is to create strongly mixing forces in the pulp between the rotor and the filter cylinder so that the fibers would penetrate the filter cylinder as effectively as possible and the knots, chops and the like were separated from the rest.
  • US patent specifications 4188286 and 4202761 illustrate a filter apparatus, which has a rotatable cylindrical rotor inside the filter cylinder.
  • Protrusions have been arranged on the rotor surface on the filter cylinder side, and the protrusions are V-shaped of their axial cross-section in such a way that the one rotational edge has an evenly rising front surface, a surface parallel to the rim of the rotor and a back surface substantially perpendicular against the rotor surface.
  • These protrusions are arranged on the surface of the rotor cylinder in a particular angle position relative to the axial direction so that all the protrusions of the rotor are at a similar position relative to the axis of the rotor.
  • pulp can be introduced into this apparatus at either side of the filter cylinder. If pulp is introduced to the outside of the filter cylinder and the accept is discharged from the inside of the filter cylinder, in other words from the rotor side, the rotational direction of the rotor is such that the accept is subjected to a downwardly inclined force component by the angle position of the protrusions and that said inclined/rising surface of the protrusions operates as a front surface.
  • the pulp is introduced between the rotor and the filter cylinder, in other words the accept is discharged from the outside of the filter cylinder, the rotational direction is opposite relative to the previously described, the protrusions tend to slow down the downwardly flowing pulp and the surface which is perpendicular relative to the surface of the rotor cylinder operates as the front surface.
  • the first mentioned blade rotor creates too strong pressure pulses at the accept side of the filter cylinder, and is not therefore suitable for example, in head boxes of the paper machines since they should not have any fluctuation of pressure.
  • the apparatus also tends to dilute the accept, and therefore the blade rotor is not applicable in apparatuses, which require pulp of a constant consistency.
  • fractionation also takes place in the screen comprising a "bump rotor", in other words the mutual relation between the fractions of the fiber suspension supplied to the filter cylinder changes in the screen in such a way that the relation of the fractions of the accept is no longer the same as that of the originally supplied pulp.
  • a "bump rotor” the extent of change of said fractionation was in the experiments between 5 to 10 % according to the clearance of the filter cylinder and the rotor. The corresponding extent of change with a blade rotor was about 20 %, and therefore even a "bump rotor" is a considerable improvement to the previous apparatuses.
  • a respective operating method is appreciated from the arrangement disclosed in the US-patent application 4188286, in which the protrusions are inclined relative to the axis of the filter cylinder.
  • the main purpose of the inclination is to prevent the fiber or fiber flocs from attaching to the front edge of the protrusion and from being conveyed with it.
  • a secondary purpose is to bring the accept pulp in the treatment space between the rotor and the filter cylinder subject to a downward force component, by which it is possible to accelerate to some extent the operation of a filter apparatus, at least to accelerate the discharge of the accept from the filter.
  • the most developed embodiment in the market at the moment is illustrated by the method in accordance with FI patent 77279 and by the arrangement developed to realize this method.
  • the method in accordance with said patent is characterized in that fiber suspension is subjected to axial forces, the intensity and the direction of which vary according to the mutual axial position between the point of application and the counter surface of the filter cylinder, and which are utilized to change the axial speed profile of the fiber suspension yet maintaining the direction of the flow continuously towards the discharge end.
  • the apparatus in accordance with said invention is characterized in that at least one of the counter surfaces of the filter cylinder, being against the other, has at least one bump or the like, the direction of the front surface of which varies according to the axial position of the bump and by which the pulp particle in the space between the counter surfaces is subjected to an axial force component, the intensity of which varies in function of the axial position of the counter surfaces of the pulp particles, and which changes the speed profile of the fiber suspension flowing between the comter surfaces.
  • the present invention relates to a method and apparatus for conveying the above mentioned thicker and courser pulp portion from the filter surface towards the surface of the rotor so that the fresher pulp comes into direct communication with the filter surface, whereby the defects or disadvantages of the prior art apparatuses have been eliminated or minimized.
  • the method in accordance with the present invention is characterized in that the friction concentrated adjacent to the filter surface and/or containing courser material is subjected to a force component directed away from the filter surface, by means of which said fraction is conveyed away from the adjacence of the filter surface.
  • An embodiment of the apparatus in accordance with the present invention is characterized in that at least one guide plate is arranged to communicate with the counter member of the filter surface, which guide plate guides the coarser and/or thicker suspension concentrated adjacent to the filter surface, away from the adjacence of the filter surface.
  • the counter surface to the filter surface has at least one member, which is formed by a protrusion arranged on the counter surface and a guide plate extending from the level of the counter surface higher than said protrusion, which protrusion and guide plate leave an opening therebetween, through which the thicker and/or coarser fraction can flow under the guide plate.
  • a filter apparatus in accordance with a preferred embodiment of the invention, comprises the following members: an outer casing 2, conduit 3 for the inflowing pulp, conduits 4 and 5 for the accept and the reject respectively, a stationary filter cylinder 6 and therein a substantially cylindrical or possibly conical rotor 7 having a shaft 8 with drive means 9.
  • the filter cylinder 6 may, in principle, be of any previously known type, but the best results are achieved, if a contoured filter cylinder is used.
  • the apparatus in accordance with the drawing operates in such a way that the fiber suspension is introduced through conduit 3 and flows to the gap between the filter cylinder 6 and the rotor 7, to the so called "treatment" space.
  • Fig.1 also teaches that members 10 on the surface of the rotor 7, on the side facing the filter cylinder 6 the shape of which members 10 may vary, for example, in the way described in FI patent 77279, according to in which zone they are located, in other words, in which axial part of the rotor they are located.
  • Fig.2 is a schematic illustration of a member 10, the front surface 11 of which may be either parallel to the direction of the axis of the cylinder, inclined to some direction relative to the axis or further divided into portions, the inclination of which portions relative to the axis may be chosen as desired.
  • This kind of front surface 11, when moving relative to the pulp towards arrow B subjects the pulp not only to a tangential force component, but also almost always to an axial force component which pumps pulp towards the center area of the cylinder and also always to a pressure stroke towards the filter surface, intensifying the pulp treatment, due to the effect of which the acceptable fiber material and liquid are pressed through the filter and a zone of coarser, to some extent thickened material is generated on the surface of the filter.
  • the front surface 11 of a member 10 in accordance with an embodiment of FI patent 77279 is substantially perpendicular against the surface of rotor 7.
  • the front surface 11 may, of course, also be inclined either to one or the other direction.
  • the protrusion has a part 13 substantially parallel to the surface of rotor 7 and an inclined surface 14 descending from part 13 to the surface of the rotor 7.
  • the above mentioned pressure stroke which intensifies screening and also thickening, is generated exactly at the front surface of the protrusion or slightly before it, and on the other hand an underpressure zone has tended to be created on the inclined surface of the trailing side of the protrusion, which zone would draw said coarser and thickened material away from the adjacence of the filter surface.
  • Figs. 3 a and 3 b illustrate a protrusion arrangement 20 of the rotor in accordance with an embodiment of the present invention, in which arrangement a pressure pulse towards the filter surface is generated by a protrusion 22, which, in principle, may be of any shape.
  • a member 26 has been arranged at the trailing side of the front surface 24 of the protrusion 22 which member extends closer to the inner surface of the filter 6 then the protrusion 22.
  • Member 26 is further characterized by a gap 28 formed between the member and the protrusion 22, through which the thicker and courser pulp generated between the protrusion and the filter surface is allowed to pass to the space between member 26 and the rotor surface, from where it is further discharged to the adjacence of the rotor surface, as arrows A in Figs. 3 a and 3 b illustrate. Consequently, an underpressurized zone is generated between the member and the filter surface, which zone is filled by fresher, less treated pulp.
  • the member 26 is formed by a guide plate 30 made of bent plate material in the embodiment of the figure, which plate 30 corresponds to the inclined trailing surface 14 of the member 10 in the arrangement illustrated in Fig.
  • Plate 32 prevents the flow of the fiber material, which has flowed under part 26 from flowing to the upstream side of the protrusion, and on the other hand, also the suspension flowing along the surface of the rotor from flowing under the guide plate 30.
  • Fig.4 illustrates a protrusion 20 in accordance with Fig.3, which communicates with a backwardly inclined plate 40 arranged to the downstream side of it, the purpose of which plate 40 is to guide the unscreened or at least less screened pulp, which has flowed along the surface of the rotor, from under the part 26 to above the flowing pulp layer.
  • the objective is to replace the thickened pulp including reject and flowing according to arrow A by fresh pulp flowing from the filter surface adjacent to the rotor surface according to arrow E.
  • Figs. 5 a , b and c illustrate how the pulp replacement in accordance with the invention may be realized when so called bump rotors in accordance with the prior art are used.
  • the bump is formed either by an exactly hemispherical or at least a sherical calotte-shaped protrusion, which may either be a closed protrusion 50 (Fig.5 a ) attached to the surface of the rotor or in some cases possibly a protrusion 52 (Fig5 b ) pressed on the casing of the rotor from inside of the rotor.
  • a scraper 54 may of course be either a completely separate b4nt protrusion made of metal or the like material (Fig.5 a ) or a protrusion pressed more deeply from inside of the surface of the rotor (Fig.5 b ), which protrusion is open substantially from the top and from the downstream side as illustrated in Figs.5 b and 5 c .
  • the operation corresponding to the previous embodiments may be created by a so called blade, for example, in such a way that both the outer and the inner surfaces of the blade are provided with guide plates arranged within certain distances from each other, which guide plates either "cut" coarser fiber material, thickened adjacent to the filter surface, carry it into the blade and remove it on the trailing edge of the blade to the other side of the blade or guide in a corresponding way fresher, less treated suspension through the inner space of the blade to the filter surface.
  • said flow passages of the suspension inside the blade must be separated from each other with intermediate walls, which may be either perpendicular against the blade surfaces or in a suitably chosen angle relative to them.
  • the guide plates are further characterized in that they are located intermittently relative to each other on the opposite surfaces of the blade.
  • An alternative to the above described arrangement is to arrange the guide plates above the blade surface with intermediate members in such a way that the flow of the desired pulp fraction takes place from between the blade and the guide plate.
  • a rotor provided with the protrusion or blade construction in accordance with the invention is applicable to be utilized both with smooth and grooved filter cylinders, so the filter cylinder may be either completely smooth or grooved in different ways, as described in FI-patent 77279.
  • new rotors may be applied in older type of filter cylinders and vice versa. This results in a filter cylinder-rotor combination operating better than the previous screening and thickening arrangements.
  • the rotor arrangement in accordance with the invention was tested in the performed experiments in connection with different filter cylinders and different rotors were compared with each other.
  • the filter cylinders used in the experiments were both smooth cylinders and cylinders made of different plate contours.
  • the test results were examined and it was discovered that the apparatus in accordance with the invention operates with all filter cylinders more effectively than the other rotors.
  • the most preferred filter embodiment according to these tests was a filter cylinder, the grooves of which were formed substantially by the bottom surface parallel to the cylinder casing, the inclined side surface on the upstream side (the inflow direction of the flow) relative to the bottom surface and the side surface substantially perpendicular against the casing surface of the cylinder on the downstream side relative to the bottom surface.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
EP90305288A 1989-05-17 1990-05-16 Procédé et dispositif pour le traitement d'une suspension de fibres Withdrawn EP0398685A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI892356A FI84191C (fi) 1989-05-17 1989-05-17 Foerfarande och anordning foer behandling av fibersuspension
FI892356 1989-05-17

Publications (1)

Publication Number Publication Date
EP0398685A1 true EP0398685A1 (fr) 1990-11-22

Family

ID=8528440

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90305288A Withdrawn EP0398685A1 (fr) 1989-05-17 1990-05-16 Procédé et dispositif pour le traitement d'une suspension de fibres

Country Status (6)

Country Link
EP (1) EP0398685A1 (fr)
JP (1) JPH0364590A (fr)
KR (1) KR900017668A (fr)
BR (1) BR9002307A (fr)
CA (1) CA2016966A1 (fr)
FI (1) FI84191C (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0436888A2 (fr) * 1990-01-06 1991-07-17 Hermann Finckh Maschinenfabrik GmbH & Co. Rotor pour tamis sous pression pour le nettoyage des suspensions de fibres
FR2666598A1 (fr) * 1990-09-10 1992-03-13 Escher Wyss Gmbh Procede de separation, notamment de tri ou de fractionnement d'une suspension de pate a papier.
GB2284394A (en) * 1992-09-02 1995-06-07 Total Mobility Vehicles Ltd Independent wheel suspension
FR2790270A1 (fr) * 1999-02-26 2000-09-01 Lamort E & M Procedes et moyens pour la filtration de la pate a papier
CN117066107A (zh) * 2023-10-16 2023-11-17 甘肃省地质矿产勘查开发局第三地质矿产勘查院 一种应用于炭浆法提金的碎屑去除设备

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2735089B2 (ja) * 1993-03-22 1998-04-02 株式会社サトミ製作所 軽質の細かい異物の除去方法
SE526033C3 (sv) * 2003-11-06 2009-12-08 Metso Paper Inc Silanordning och silkorg för silning av massasuspensioner

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953325A (en) * 1972-09-27 1976-04-27 Nelson Douglas G Pulp screen with rotating cleaning foil
FR2547605A1 (fr) * 1983-06-14 1984-12-21 Escher Wyss Gmbh Dispositif de triage de matieres fibreuses pour la fabrication de papier
EP0289020A2 (fr) * 1987-04-30 1988-11-02 A. Ahlstrom Corporation Procédé et dispositif pour le traitement d'une suspension de fibres

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5841889A (ja) * 1981-09-05 1983-03-11 Otsuka Chem Co Ltd 縮合したポリアルコキシホスフアゼン化合物の製造法
FR2516563A1 (fr) * 1981-11-18 1983-05-20 Lamort E & M Perfectionnements aux epurateurs de pate a papier et a leurs tamis
JPS58133009A (ja) * 1982-02-02 1983-08-08 Nippon Gakki Seizo Kk 電力増幅器
JPH089838B2 (ja) * 1987-07-08 1996-01-31 エイ．アフルストロム コ−ポレ−ション 繊維懸濁液を濃化する方法と装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953325A (en) * 1972-09-27 1976-04-27 Nelson Douglas G Pulp screen with rotating cleaning foil
FR2547605A1 (fr) * 1983-06-14 1984-12-21 Escher Wyss Gmbh Dispositif de triage de matieres fibreuses pour la fabrication de papier
EP0289020A2 (fr) * 1987-04-30 1988-11-02 A. Ahlstrom Corporation Procédé et dispositif pour le traitement d'une suspension de fibres

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0436888A2 (fr) * 1990-01-06 1991-07-17 Hermann Finckh Maschinenfabrik GmbH & Co. Rotor pour tamis sous pression pour le nettoyage des suspensions de fibres
EP0436888A3 (en) * 1990-01-06 1991-08-21 Emil Holz Rotor for pressure screens for screening fibre suspensions
FR2666598A1 (fr) * 1990-09-10 1992-03-13 Escher Wyss Gmbh Procede de separation, notamment de tri ou de fractionnement d'une suspension de pate a papier.
GB2284394A (en) * 1992-09-02 1995-06-07 Total Mobility Vehicles Ltd Independent wheel suspension
GB2284394B (en) * 1992-09-02 1995-11-15 Total Mobility Vehicles Ltd Independent wheel suspension
FR2790270A1 (fr) * 1999-02-26 2000-09-01 Lamort E & M Procedes et moyens pour la filtration de la pate a papier
US6679384B1 (en) 1999-02-26 2004-01-20 Kadant Lamort Method and means for paper pulp filtering
CN117066107A (zh) * 2023-10-16 2023-11-17 甘肃省地质矿产勘查开发局第三地质矿产勘查院 一种应用于炭浆法提金的碎屑去除设备
CN117066107B (zh) * 2023-10-16 2023-12-12 甘肃省地质矿产勘查开发局第三地质矿产勘查院 一种应用于炭浆法提金的碎屑去除设备

Also Published As

Publication number Publication date
FI892356A0 (fi) 1989-05-17
FI892356A (fi) 1990-11-18
FI84191B (fi) 1991-07-15
FI84191C (fi) 1992-11-25
CA2016966A1 (fr) 1990-11-17
KR900017668A (ko) 1990-12-19
BR9002307A (pt) 1991-08-06
JPH0364590A (ja) 1991-03-19

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