EP0629738A1 - Rotor pour l'épuration hydrodynamique sous pression de pâte à papier, et appareil muni de ce rotor - Google Patents

Rotor pour l'épuration hydrodynamique sous pression de pâte à papier, et appareil muni de ce rotor Download PDF

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Publication number
EP0629738A1
EP0629738A1 EP94401238A EP94401238A EP0629738A1 EP 0629738 A1 EP0629738 A1 EP 0629738A1 EP 94401238 A EP94401238 A EP 94401238A EP 94401238 A EP94401238 A EP 94401238A EP 0629738 A1 EP0629738 A1 EP 0629738A1
Authority
EP
European Patent Office
Prior art keywords
rotor
shoulder
screen
axis
angle
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Withdrawn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
EP94401238A
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German (de)
English (en)
French (fr)
Inventor
Jean-Pierre Lamort
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.)
Kadant Lamort SAS
Original Assignee
E&M Lamort Fils SA
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 E&M Lamort Fils SA filed Critical E&M Lamort Fils SA
Publication of EP0629738A1 publication Critical patent/EP0629738A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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

Definitions

  • the present invention relates to a rotor for the hydrodynamic purification under pressure of paper pulp originating in particular from recycling old paper, and to the device provided with this rotor.
  • the apparatus comprises in a closed tank a cylindrical screen and a closed cylindrical rotor provided at its periphery with blades which sweep the screen while moving at high speed and at very short distance from the sheet perforated.
  • This device can operate either centrifugal or centripetal depending on the direction of rotation of the rotor.
  • the perforations are holes or slots depending on the nature of the dough and impurities, and the inner surface of the sieve is smooth or profiled, the perforation being located at the bottom of the groove in the latter case.
  • the blade is wedge-shaped with a radial edge and an edge inclined at an angle of 20 to 30 ° on the wall of the rotor. Whatever the direction of rotation, the dough between the rotor and the screen is rotated with the rotor. For centrifugal operation the radial face perpendicular to the rotor is similar to a scraper which pushes the dough.
  • the coarse pulp from the primary disintegration treatments in pulpers is filtered in this device intended for centrifugal operation.
  • the coarsest impurities are removed.
  • the dough which then contains only small impurities is filtered in an identical device intended for centripetal operation.
  • centrifugal purification device it includes a sieve inside which rotates a rotor composed of eccentric lobes ( relative to the longitudinal axis of the sieve ); for example the lobes are eccentric towards one another: the cylinder has an oval shape in cross section.
  • this rotor is to produce pulsations which prevent clogging of the screen: the portion of the rotor which approaches the screen produces an increase in pressure, the portion of the rotor which moves away from the screen produces a depression.
  • the purifier is centrifugal and has a closed rotor, produced as in the previous document from the lobes of an eccentric cylinder; but instead of being eccentric towards one another, they are by sliding one over the other which gives, in cross section two offset half-cylinders.
  • This rotor rotates in front of a profiled sieving surface similar to that described in FR-A-2 410 081.
  • the operating principle is the same: the rotor has two opposite shoulders which extend over the entire length of the sieve and which have the function of driving the dough in motion at speed rotor. The shoulders are squeegees. But unlike the blade of the aforementioned device, the rear face of the shoulder is not flat and inclined, it is cylindrical and thus the depression created behind the shoulder is less and distributed over a larger peripheral surface. .
  • this device can give good results as regards the purification flows, it has the drawback of having a large fractionation which the turbulence caused by the profile of the screen only limits.
  • the main objective of the invention is to provide an apparatus which avoids this fractionation.
  • centrifugal purification devices with open drum: the devices, well known (for example by FR-A-1.546 .515), consist of a cylindrical screen inside which rotates a rotor in its axis.
  • the rotor consists of an axial shaft which carries arms at the ends of which blades are mounted which have a hydrodynamic profile.
  • the object of the present invention is to provide a purification device allowing centrifugal or centripetal operation, usable in primary purification for the sieving of pulp very rich in impurities, giving purification results at least equal to those of known devices and without splitting.
  • the subject of the invention is a rotor for the hydrodynamic purification under pressure of paper pulp from old paper in purifiers of known type comprising a cylindrical screen characterized in that it comprises a body of generally cylindrical shape extending along a longitudinal axis of rotation and which comprises a succession along the longitudinal axis of n identical elements juxtaposed, each element having a cylindrical shape , the wall on the side of the screen having a shoulder on either side of which it describes a spiral winding around the longitudinal axis over less than 360 °, the foot and the top of the shoulder forming with respect to said axis a very small angular deviation so that the face of the shoulder is inclined towards the surface of the screen, the angle of this inclination relative to the radial plane passing through the foot of the shoulder being between 5 ° and 80 °, the elements being offset in rotation from one to the other by an angle ( ⁇ ) of a value of at least (360 / n) °, n being equal to at least 3.
  • the rotor in a first embodiment, is designed to perform centrifugal cleaning. It is a closed drum formed for stacking n identical elements, and placed inside the sieve.
  • the angle of inclination of the shoulder is between 5 and 45 °, preferably between 10 and 30 °.
  • the rotor is designed to carry out a centripetal purification.
  • the rotor surrounds the screen from the outside; it is a body of revolution of cylindrical outer wall and inner spiral wall according to the preceding definition.
  • the angle of inclination of the shoulder is between 10 and 60 °.
  • the invention also relates to the apparatus for hydrodynamic purification under pressure of paper pulp.
  • the apparatus is of the type comprising a closed tank containing at least one fixed cylindrical screen separating two chambers, and a rotor coaxial with the screen according to any one of the preceding definitions.
  • the device is equipped with a rotor intended for centrifugal purification.
  • the purification apparatus comprises a closed volume 1 provided with an inlet 2 for raw pulp, an outlet 3 for purified pulp and an outlet 4 for rejects.
  • a fixed cylindrical sieve 5 with a longitudinal axis 6 is mounted in the volume in a manner known per se. It determines in the volume two chambers: a chamber 21 for the incoming dough, an outlet chamber 23 for the incoming dough.
  • a rotor 7 of generally cylindrical body is mounted in the volume coaxially with the sieve.
  • This rotor 7 is a closed drum in which the dough does not penetrate. It consists of a coaxial juxtaposition of a plurality of identical elements 8 8.1, 8.2, 8.3, each of generally cylindrical shape composed of a wall 9 wound in a spiral over approximately 360 ° between two plane walls 10,11 perpendicular to the axis 6.
  • the two ends 12, 13 of the wall are offset radially and connected by a surface element 14, preferably planar, forming a shoulder.
  • the two ends 12, 13 are further apart from one another so as to give, relative to the longitudinal axis 6, a very small difference ⁇ , of the order of 30 '' a few degrees for example.
  • the face or plane of the shoulder 14 is inclined towards the surface of the screen, that is to say towards the rear with respect to the radial plane 15 passing through the foot 12 of the shoulder at an angle ⁇ of l '' from 10 ° to 30 °.
  • the elements 8 of the rotor are offset in rotation with respect to each other by the same angular value ⁇ .
  • the rotor consists of three elements 8.1; 8.2; 8.3; the shoulders are offset by an angle of (360/3) ° or 120 ° between them ( Figure 5).
  • the rotor can be made up of 4, 5 elements or many more; the corresponding angular difference ⁇ would be (360/4) °, (360/5) °, etc.
  • each element carries such a member which has the shape of a blade. It is arranged on the wall 9 opposite the diametrical opposite of the shoulder 14 and made with the plane 17, perpendicular to the longitudinal axis 6, an angle ⁇ between 1 and 15 °, the value of the angle being chosen. in particular according to the nature of the dough, its concentration and the characteristics of the sieve and the desired longitudinal circulation speeds. (figure 4).
  • the height 18 of the blade varies so as to remain in the cylindrical template 19 of the rotor.
  • the leading edge 20 of the blade is inclined at an angle ⁇ of the order of 45 to 70 °, in the example of about 60 °, so as to avoid the formation of clumps of fibers.
  • the shoulders 14 can be inclined at an angle ⁇ relative to the longitudinal axis 6, between approximately -15 °. and + 15 ° in order to act on the longitudinal movement of the dough.
  • any combination of the inclinations of the shoulders and of the blades 16 may be provided.
  • the first shoulder 14.1 may be inclined by 7 °, the second 14.2 by 0 °, and the third 14.3. -5 °, that is to say a reverse inclination towards the central element 8.2 of the rotor.
  • Such an arrangement makes it possible to act on the residence time of the dough in the sieving space (circulation speed).
  • the elements 8 are offset backwards with respect to each other, in the sense that the direction of rotation of the rotor being that indicated by the arrow R (the shoulder being an edge d 'attack), the second shoulder 14.2 is behind the first 14.1 with an offset of 120 °, the third is still behind 120 °.
  • the operation of the apparatus is as follows: the paste being supplied under pressure at 2 enters the inlet chamber 21 then into the screening space 22.
  • the paste pushed by the inclined shoulder 14 is applied against the interior surface of the sieve 5, then it undergoes a constant low vacuum and continues until the return of the shoulder.
  • the paste therefore undergoes successive applications (one at each passage of the shoulder), and the sieving seems to be obtained by the force of these repeated pulsations against the perforated surface.
  • the longitudinal movement can be accelerated or slowed down by the arrangement of the blades (their number, their inclination), the longitudinal inclinations of the shoulders and also by the direction of the shifts of the elements between them ( ⁇ ⁇ ).
  • the value of the inclination ⁇ of the shoulder 14 is chosen so as to, on the one hand, avoid the wedge effect with the wall of the sieve, which can happen beyond 40 ° and, on the other hand, limit the rotational movement of the dough as much as possible.
  • the shoulder is inclined in order to avoid or minimize the entrainment of the dough. Everything happens as if the paste, projected by this inclined surface towards the sieve, was applied and immobilized on the sieve. So unlike existing devices where the shoulder is a doctor blade which has the function of driving the dough at the speed of the rotor, here the inclination of the shoulder has the opposite function in order to obtain a considerable speed difference, such as in open rotors. As the speed of the moving dough is very low, so is the centrifugal force, and the constant vacuum which follows the shoulder is then sufficient to balance this weak centrifugal force. Under this balance, filtration appears to be carried out under the only differential pressure between the walls of the screen, created by the feed.
  • the device is equipped with a rotor intended for centripetal purification.
  • the device 24 comprises a closed volume 25 provided with an inlet 26 for raw pulp, an outlet 27 for purified pulp and an outlet 28 for rejects.
  • a cylindrical screen 29 of axis of revolution 30 is fixedly mounted in this volume.
  • a rotor 31, of generally cylindrical shape, is mounted coaxially with the screen in rotation around the latter on its outer face 32. It is a set of elements 80 hollow cylindrical, their wall being full.
  • the outer face 33 of each element 80 is cylindrical, of circular cross section, the inner face 34 has in cross section a spiral shape over approximately 360 °.
  • the two ends 35, 36 are offset radially and angularly by a very small angle ⁇ , and connected by a surface element 37, preferably planar, forming a shoulder.
  • the shoulder is inclined towards the surface of the screen, that is to say towards the rear with respect to the radial plane 38 passing through the foot 36 of the shoulder, by an angle ⁇ of the order of 10 to 60 °.
  • the rotor 31 is constituted by the coaxial juxtaposition of a plurality of identical elements 80.1; 80.2; 80.3, angularly offset from each other by the same angular value ⁇ relative to the axis of revolution 30.
  • centrifugal rotor All the other characteristics described for the centrifugal rotor can be applied to the centripetal rotor.
  • the rotor according to the invention provides numerous advantages, the main ones of which are illustrated in the following comparative table of centrifugal purifications produced from a constant raw pulp quality.
  • the "drum” rotor is used in an apparatus of the type described in patent FR-A 2,410,081 cited in the preamble. In each case the dimensions of the devices and the screens are identical. The results are expressed relative to the reference observation, made on the use of a drum rotor. CONCENTRATION FLOW RATE P.ABSORBEE SPLITTING Drum rotor 1 1 1 Important Open rotor 1.15 0.9 / 1.0 0.85 / 0.90 low Rotor according to the invention 1.25 1.10 0.70 very weak
  • the rotor according to the invention purify the pulp without fractionation, but the purification is faster, which allows a greater flow rate, with a pulp more concentrated in dry matter, and consumes less energy.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
  • Combined Means For Separation Of Solids (AREA)
  • Separation Of Solids By Using Liquids Or Pneumatic Power (AREA)
EP94401238A 1993-06-16 1994-06-06 Rotor pour l'épuration hydrodynamique sous pression de pâte à papier, et appareil muni de ce rotor Withdrawn EP0629738A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9307242A FR2706495B1 (fr) 1993-06-16 1993-06-16 Rotor pour l'épuration hydrodynamique sous pression de pâte à papier, et appareil muni de ce rotor.
FR9307242 1993-06-16

Publications (1)

Publication Number Publication Date
EP0629738A1 true EP0629738A1 (fr) 1994-12-21

Family

ID=9448184

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94401238A Withdrawn EP0629738A1 (fr) 1993-06-16 1994-06-06 Rotor pour l'épuration hydrodynamique sous pression de pâte à papier, et appareil muni de ce rotor

Country Status (5)

Country Link
US (1) US5476178A (fi)
EP (1) EP0629738A1 (fi)
JP (1) JPH07268793A (fi)
FI (1) FI942838A (fi)
FR (1) FR2706495B1 (fi)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1036879A1 (de) * 1999-03-17 2000-09-20 Voith Sulzer Papiertechnik Patent GmbH Drucksortierer zum Sieben einer Papierfaserstoffsuspension und Siebräumer für einen solchen

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994000634A1 (de) * 1992-06-20 1994-01-06 Hermann Finckh Maschinenfabrik Gmbh & Co. Drucksortierer für fasersuspensionen
US5566833A (en) * 1995-01-25 1996-10-22 Hermannfinckh Maschinenfabrik Gmbh & Co. Pressure sorter for fiber suspensions as well as a process for the preparation of fiber suspensions
CN1266386A (zh) * 1997-08-06 2000-09-13 塞莫·布莱克·克劳森公司 造纸浆料筛分装置和方法
US6010012A (en) * 1997-11-03 2000-01-04 Beloit Technologies, Inc. Fluidizing detrashing impeller
US8011515B2 (en) * 2009-05-12 2011-09-06 Ovivo Luxembourg S.á.r.l. Two stage pulp screening device with two stationary cylindrical screens
DE102013216433A1 (de) * 2013-08-20 2015-03-12 Voith Patent Gmbh Drucksortierer

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1921750A (en) * 1931-04-01 1933-08-08 Carl Nebrich Centrifugal separator for straining pulpy material, such as wood pulp, cellulose, paper pulp, and the like
FR1472743A (fr) * 1965-03-30 1967-03-10 Ingersoll Rand Canada Appareil de filtrage
FR2005590A1 (fi) * 1968-04-05 1969-12-12 Voith
EP0275921A2 (de) * 1987-01-22 1988-07-27 J.M. Voith GmbH Sortierflügel

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1546515A (fr) * 1967-06-14 1968-11-22 Lamort E & M Appareil pour l'épuration de liquides contenant en suspension des matières solides telles que les pâtes à papier
US3726401A (en) * 1970-12-16 1973-04-10 Bird Machine Co Screening machine
DE2712715B2 (de) * 1977-03-23 1979-05-23 Hermann Finckh Maschinenfabrik Gmbh & Co, 7417 Pfullingen Sortierer für Fasersuspensionen
FR2410081A1 (fr) * 1977-11-23 1979-06-22 Lamort Ingenieurs Construc E E Appareil pour l'epuration des pates a papier
FR2498650B2 (fr) * 1981-01-23 1986-03-21 Lamort E & M Dispositif pour l'epuration et la recuperation de pate a papier
US4855038A (en) * 1985-06-20 1989-08-08 Beloit Corporation High consistency pressure screen and method of separating accepts and rejects
US4744894A (en) * 1986-06-30 1988-05-17 Gauld W Thomas Fibrous stock screening apparatus
JPH0642931B2 (ja) * 1990-08-16 1994-06-08 孝一 荒井 スクレーパ濾過装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1921750A (en) * 1931-04-01 1933-08-08 Carl Nebrich Centrifugal separator for straining pulpy material, such as wood pulp, cellulose, paper pulp, and the like
FR1472743A (fr) * 1965-03-30 1967-03-10 Ingersoll Rand Canada Appareil de filtrage
FR2005590A1 (fi) * 1968-04-05 1969-12-12 Voith
EP0275921A2 (de) * 1987-01-22 1988-07-27 J.M. Voith GmbH Sortierflügel

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1036879A1 (de) * 1999-03-17 2000-09-20 Voith Sulzer Papiertechnik Patent GmbH Drucksortierer zum Sieben einer Papierfaserstoffsuspension und Siebräumer für einen solchen
US6311850B1 (en) 1999-03-17 2001-11-06 Voith Sulzer Papiertechnik Patent Gmbh Pressure screening apparatus for screening a paper stock suspension and screen clearer for such a screening apparatus

Also Published As

Publication number Publication date
US5476178A (en) 1995-12-19
FI942838A (fi) 1994-12-17
FR2706495A1 (fr) 1994-12-23
FR2706495B1 (fr) 1995-09-08
FI942838A0 (fi) 1994-06-15
JPH07268793A (ja) 1995-10-17

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