EP0145365B1 - Epurateur rotatif du type vertical, sous pression, ayant une alimentation en pulpe à différentes positions, axialement espacées - Google Patents

Epurateur rotatif du type vertical, sous pression, ayant une alimentation en pulpe à différentes positions, axialement espacées Download PDF

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Publication number
EP0145365B1
EP0145365B1 EP84308039A EP84308039A EP0145365B1 EP 0145365 B1 EP0145365 B1 EP 0145365B1 EP 84308039 A EP84308039 A EP 84308039A EP 84308039 A EP84308039 A EP 84308039A EP 0145365 B1 EP0145365 B1 EP 0145365B1
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EP
European Patent Office
Prior art keywords
screen
impeller
pulp
baffle
rotary
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
EP84308039A
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German (de)
English (en)
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EP0145365A3 (en
EP0145365A2 (fr
Inventor
Anthony William Hooper
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Uniweld Inc
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Uniweld Inc
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Priority to AT84308039T priority Critical patent/ATE58403T1/de
Publication of EP0145365A2 publication Critical patent/EP0145365A2/fr
Publication of EP0145365A3 publication Critical patent/EP0145365A3/en
Application granted granted Critical
Publication of EP0145365B1 publication Critical patent/EP0145365B1/fr
Anticipated expiration legal-status Critical
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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

Definitions

  • the present invention relates to rotary screening of pulp stock and more particularly to improvements in both the method and the device for screening pulp stock in pressure screens.
  • the fibers are formed into a mat between the screen plate and the impeller blades, the mat rotates due to the movement of the impeller blades and at the same time has an axial movement downwards so that the reject particles in the pulp stock are held in the mat and conveyed to the bottom of the screen where they are removed in a reject chamber.
  • the mat should retain substantially the same thickness from top to bottom, the rotating impeller blades prevent the mat from becoming too thick and causing fibers to plug holes in the screen plate.
  • the arrangement of dividing the pulp stock flow into parts, together with the locations where the parts are directed towards the screen, and the quantity of dilution water mixed with the pulp stock below these screen locations, are all variables that can be tuned to suit the geometry of a particular pulp screening device.
  • the highest rate of pulp stock flow always occurs at the inlet end of present day pulp screens, so by having different points on the screen where fresh pulp is applied increases the capacity at those points and consequently increases the capacity of the whole pulp screen.
  • the consistency of the pulp stock that has passed through the screen is similar to the consistency of the fresh pulp stock fed to the screen, whereas further down the screen there is a considerable consistency drop.
  • the effect of bringing in fresh pulp stock at different points down the screen is to reduce the overall consistency drop between the pulp stock and the screened pulp stock down the screen. A reduction of this consistency drop is beneficial to the process.
  • the present invention provides, in a rotary pulp screening device of the vertical pressure type, including a cylindrical housing having an upper inlet chamber and a lower screening chamber with a disc ring dividing the upper chamber from the lower chamber, a vertical cylindrical screen within the lower chamber, a rotary impeller mounted for rotation about a central vertical axis within the screen, the impeller having a body whose bottom is adjacent the lower end of the cylindrical screen, the body having a shape of circular axial cross section from the top to the bottom and whose diameter increases from the top to the bottom thus leaving a larger annular space at the top, and an annular inlet between the disc ring and the top of the body, means for rotating the impeller, impeller blades radiating from at least a portion of the body of the impeller and extending to within a short distance from the screen for the height of the screen, and pulp discharge outlet from the lower chamber outside the pulp screen, the improvement comprising at least one substantially frusto-conical shaped baffle, concentric with the body of the impeller, extending down from
  • the opening between the baffle and the body of the impeller has no impeller blades therein.
  • a frusto-conical inlet ring may be provided in the upper chamber extending upwards from the disc ring, with the smallest diameter at the top of the inlet ring, and the rotary impeller has a cone portion formed to the paraboloidal segment shaped body to form an approximate paraboloid shape.
  • the axial height of the baffle is preferably about 20% of the height of the cylindrical screen and dilution water is preferably applied to the cylindrical screen below the baffle.
  • the impeller has a paraboloidal segment shaped body, which may be formed from a plurality of frusto-conical segments.
  • the impeller has a frusto-conical shaped body.
  • two baffles are provided one above the other, positioned such that the flow of pulp stock entering the annular inlet is divided into three parts, a first part passing through a first annular space between the top of the first baffle and the disc ring, a second part passing through a second annular space between the bottom of the first baffle and the top of the second baffle, and a third part passing through a third annular space between the bottom of the second baffle and the surface of the body of the impeller.
  • three baffles may be provided, this embodiment is particularly useful in high screens. Again the height of each baffle is preferably about 20% of the height of the cylindrical screen.
  • a still further embodiment provides for a plurality of baffles, extending downwards one below the other.
  • a rotary impeller adapted to rotate inside a cylindrical screen of a pulp screening device of the vertical pressure type, the impeller comprising a body having a shape with circular axial cross section from top to bottom whose diameter increases from the top to the bottom, impeller blades radiating from at least a portion of the body of the impeller and extending to within a short distance from the screen for the height of the screen, at least one substantially frusto-conical shaped baffle concentric with the body of the impeller, extending down from the top of the impeller, adapted to divide flow of pulp stock, the baffle forming an annular axial cross sectional opening between the baffle and the body of the impeller having a substantially similar cross sectional area at the inlet end as at the bottom of the baffle, the baffle joined exteriorly to the impeller blades.
  • a process of screening a pulp stock in a rotary pulp screening device of the vertical pressure type including, a cylindrical housing having an upper inlet chamber and a lower screening chamber with a disc ring dividing the upper chamber from the lower chamber, a vertical cylindrical screen within the lower chamber, a rotary impeller mounted for rotation about a central vertical axis within the screen, the impeller having a body whose bottom is adjacent the lower end of the cylindrical screen, the body having a shape of circular axial cross section from the top to the bottom thus leaving a larger annular space at the top, and an annular inlet between the disc ring and the top of the body, means for rotating the impeller, impeller blades radiating from at least a portion of the body of the impeller and extending to within a short distance from the screen for the height of the screen, and pulp discharge outlet from the lower chamber outside the pulp screen, wherein pulp stock entering the annular inlet is rotated by the impeller blades, flows down the screen and mixes with dilution water, the pulp stock passing
  • the flow of pulp stock is divided into a plurality of equal parts, the first part directed at the top of the screen and the remaining parts directed at distances apart representing about 20% of the height of the screen.
  • FIG. 1 One embodiment of a pulp screening device 10 is shown in Fig. 1 having a generally cylindrical housing 11 with a top cover 12 joined to the cylindrical housing 11 at flange 13.
  • the cylindrical housing 11 has a lower flange 14 which rests on a casing bottom flange 15 supported on a base plate 16.
  • a disc ring 17 which divides the housing into an upper inlet chamber 18, above the disc ring 17, and a lower screening chamber 19, below the disc ring 17.
  • Atubular inlet pipe 20, having a flange 21, at the end thereof provides entry to the inlet chamber 18.
  • a conical inlet ring 22 has a lower flange 23, at its largest diameter which rests on the disc ring 17. The lower flange 23, overlaps the disc ring 17, so that pulp stock passing into the inlet chamber 18, moves up the conical side of the inlet ring 22, and passes over the small diameter lip 24, flowing downwards through the conical inlet ring 22, into the lower chamber 19.
  • a vertical cylindrical screen 25, is mounted axially in the lower chamber 19, and extends for the full height of the chamber 19, from the lower flange 14, to the disc ring 17.
  • An accept chamber 26, is provided in the lower chamber 19, outside the screen 25.
  • An outlet 27, at the bottom of the accept chamber 26, in the cylindrical housing 11, outside the screen 25, allows the screened accept fibers to leave the screening device 10.
  • a flange 28, at the end of the outlet 27, provides a connection to discharge ducts.
  • a rotary impeller 30, is positioned axially within the screen 25.
  • the rotary impeller 30, in the screening area is shaped approximately in the form of a paraboloid segment.
  • the paraboloid segment is formed from a series of truncated cones joined together and has a curved nose cone 31, on the top so the overall shape of the impeller is paraboloidal.
  • the impeller 30, is made in this manner for ease of construction but the approximate paraboloid shape provides streamline flow to the screen.
  • the nose cone 31, extends up into the conical inlet ring 22, of the upper chamber 18.
  • the tip of the nose cone 31, may be the same height as the top of the screen 25.
  • that portion of the impeller 30, within the screening area forms what is referred to as a paraboloidal segment.
  • the nose cone 31, may be omitted.
  • the shape of the impeller may be formed from only two truncated cones with different slopes as disclosed in US-A-3,713,536.
  • the present invention can be applied to existing rotary screens by retrofitting a new impeller in an existing screen.
  • the retrofit impeller may have a frusto-conical shape rather than a paraboloid shape or two different truncated cones with different shapes.
  • the rotary impeller 30, is mounted on a rotating axial shaft 32, which rotates in a bearing assembly 33, on the axis of the cylindrical screening device 10.
  • the lower drive shaft 34 may have a V-belt pulley (not shown) mounted thereon for connection by means of V-belts to an electric motor.
  • a number of impeller blades 35 are equispaced about the rotary impeller 30, radiating from at least a portion of the body of the impeller 30.
  • the blades 35 extend to within a short distance from the screen 25, for the full height of the screen 25, leaving an annular space 36, between the tips of the blades 35, and the screen 25. Details of the arrangement of rotor blades 35, and impeller 30, are shown in more detail in Figs. 2-5.
  • An annular inlet 40 is formed at the top of the paraboloidal segment shaped body of the impeller 30, at the level of the disc ring 17, where the pulp stock passes from the inlet ring 22, into the lower screening chamber 19.
  • a top baffle 41 having a substantially frusto-conical shape is located concentric with the surface of the impeller 30 extending down from the annular inlet 40.
  • the top baffle 41 is shown substantially parallel with the surface of the impeller 30 for the height of the top baffle 41. It is not essential for the baffle 41 to be parallel to the surface of the impeller 30, however, it is necessary for the annular axial cross sectional opening between the baffle 41 and the surface of the impeller 30 to have a substantially similar cross sectional area for the full height of the baffle 41. By keeping this cross sectional area constant for the height of the baffle, the velocity of the pulp stock passing between the baffle 41, and the surface of the impeller 30, remains about the same.
  • the baffles are described as being frusto-conically shaped, however, they may be flat or curved, dependent upon the shape of the impeller surface and are designed to provide constant velocity to the pulp stock flowing therein.
  • a second frusto-conical shaped baffle 42 also concentric with the surface of the impeller 30, is positioned below the top baffle 41, leaving an aperture 43, between the bottom of the top baffle 41, and the top of the second baffle 42.
  • the second baffle 42 is shown as being substantially parallel to the surface of the impeller 30, for the height of the second baffle 42.
  • the cross sectional area between the second baffle 42, and the surface of the impeller 30, is substantially the same for the height of the second baffle 42.
  • the annular space between both baffles 41 and 42 and the surface of the impeller 30, may have no impeller blades therein, and therefore is open.
  • the impeller blades 35 radiate outward from the baffles 41 and 42 to the annular space 36, so that the tips of the blades 35, extend for the full height of the screen.
  • the annular space between the impeller blades 41 and 42, and the surface of the impeller 30, is open, that is to say no impeller blades extend through this space so that initially when pulp stock enters this area it is not immediately rotated by the action of the impeller blades 35.
  • baffles 41, and 42 divides the flow of pulp stock entering the pulp inlet 40, into separate parts, two baffles provide three parts of pulp stock flow directed at different heights down the pulp screen 25.
  • the position of the top baffle 41 in the annular inlet 40 is such that the pulp stock flow is divided into two parts, a first part which flows outside the top baffle 41, between the top baffle 41 and the bottom of the inlet ring 22, into the impeller blades 35, where it is immediately rotated by the impeller blades.
  • Much of this first part of the pulp stock passes through the top portion of the screen 25, however, a rotating mat of fibers is formed, and there is an axial flow of pulp stock vertically down the screen.
  • the second part of the pulp stock flow entering the annular inlet 40 flows down the surface of the impeller 30, and in the preferred embodiment is not subjected to substantial rotation.
  • the first part and the second part of pulp stock flow may be about equal, or the second part may be twice that of the first part, depending upon the arrangement of baffles.
  • the second part is then divided into two separate and substantially equal parts at the bottom of the top baffle 41.
  • the first of these two equal parts exits through aperture 43, and is immediately rotated by the impeller blades.
  • Much of the pulp stock in this second part joins the rotating mat of fibers and passes through the screen, however, there is an axial vertical movement of the pulp stock in the mat of fibers down the surface of the screen.
  • each of the baffles 41 and 42 is preferably substantially the same, each baffle has a vertical height of approximately 20% of the total height of the cylindrical screen 25.
  • pulp stock entering the annular inlet 40 is in effect divided, and three parts of pulp are delivered to the impeller blades 35, and consequently to the pulp screen 25, at different heights along the pulp screen 25.
  • the height of the baffles and the position of the baffles is determined primarily by the flow characteristics entering the annular inlet 40. Other considerations include the type of screen and the type of pulp stock being screened. The criteria is to ensure that the axial movement of pulp stock moving down the screen has substantially the same velocity from top to bottom of the screen.
  • Figs. 1 and 2 small pulp screening devices may have only one baffle therein, tall pulp screening devices may have three or more baffles. Again the criteria being that the axial velocity of the pulp stock down the screen is arranged to be substantially the same from top to bottom of the screen.
  • impeller blades 35 may be incorporated with rotary pulp screen of the present invention.
  • One type of impeller blade is illustrated in Figs. 3, 4 and 5A, and other types are illustrated in Figs. 5B to 5G.
  • the selection of impeller blades is made dependent upon a number of factors such as the type of pulp stock being screened, the desired properties of the screened pulp, and the capacity of the pulp stock through the rotary pulp screen. These listed factors are by no means limiting, neither do they represent the only factors.
  • the impeller blades 35 shown in Figs. 3, 4 and 5A have a first leading blade 50, and a second trailing blade 51, which are spaced apart with a gap 52 therebetween the blades 50 and 51, to allow dilution water to be sprayed directly from the body of the impeller 30, below the lower baffle 42, and have a plurality of holes 53, in the gap 52, between the blades 50 and 51 to allow dilution water to be sprayed directly onto the pulp screen 25.
  • dilution water is added at locations on the pulp screen 25, below where the parts of pulp stock are fed onto the screen.
  • Sufficient dilution water is applied such that the axial velocity of the mat of fibers moving down the face of the screen remains the same or substantially the same for the full height of the screen 25.
  • Fig. 5B the leading blade 50, extends to within a short distance from the screen, and the second trailing blade 51, does not extend so far.
  • Figs. 5C, 5D, and 5E illustrate an impeller blade assembly with a cap 55, across the ends of the leading blade 50, and the trailing blade 51, and an exit aperture 56, in the trailing blade 51, for the dilution water.
  • Figs. 5F and 5G show a single trailing blade 51, and leading blade 50 respectively without a second blade.
  • the dilution water is fed to the screen directly from the hole 53, in the body of the impeller 30. In all embodiments shown, different flows of dilution water are provided down the screen to ensure that the axial velocity of pulp stock is substantially constant down the screen.
  • a water inlet duct 57 shown in Fig. 1 leads to an annular chamber 58, having an opening 59 at the top thereof, allowing dilution water to pass into that portion of the interior of the impeller body that is beneath the lower baffle 42.
  • a diaphragm plate 60 extending across the body of the impel-Ier30, prevents dilution water passing into the top of the impeller body.
  • a reject chamber 61 is provided beneath the screen 25, and as shown in Fig. 4, an impeller blade 50, extends down into the reject chamber 61, to continually sweep the chamber. In another embodiment there is virtually no reject chamber.
  • An outlet (not shown) is provided so that fiber rejects, shives, etc., which pass down the screen and do not pass through the screen, exit from the reject chamber or from the bottom of the screen.
  • the impeller blades rotate the pulp stock and a mat of pulp fibers is formed between the edges of the blades and the screen.
  • This mat rotates relative to the screen and also has an axial movement which is at a substantially constant velocity right down to the reject chamber 61. Due to this rotational and axial movement of the mat, the thickness of the mat remains about the same for the screen height and a shearing force occurs between one side of the mat and the tips of the impeller blades which prevents the holes in the cylindrical screen from plugging.
  • the accept pulp fibers pass through the fiber mat which is formed by the shives and other reject fibers, together with the accept fibers, and then pass through the screen into the accept chamber 26.
  • This axial movement of the mat is substantially constant down the face of the screen, and in order to retain its speed after the lower baffle 42, the dilution water ensures that the mat continues its rotation and downward movement.
  • one supply may be at a higher pressure or higher flow than the other supplies to ensure the axial velocity of the mat is substantially the same down the height of the screen.
  • the rejects in the mat then pass into the reject chamber 61, where they are ejected through the outlet.
  • the accept or screened pulp stock passes out of the accept chamber 26, through the outlet 27.
  • Fig. 6 shows another embodiment of the pulp screening device with only one baffle 41.
  • Fig. 7 shows a pulp screening device with three baffles, a first baffle 41, second baffle 42 and a third baffle 70. The spacing between the three baffles is such that the pulp stock flow entering inside the first baffle 41, is divided into three substantially equal parts when exiting between the first baffle 41, and second baffle 42, between the second baffle 42, and the third baffle 70, and below the third baffle 70.
  • Fig. 8 shows an impeller 30, which has a frusto-conical shape, and only one slope from the top to bottom. A single baffle 41, is illustrated. This type of impeller would likely be provided to be installed in older types of pulp screening devices.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
  • Refuse Collection And Transfer (AREA)
  • Confectionery (AREA)

Claims (19)

1. Dispositif classeur de pâte rotatif (10) du type vertical à pression, comprenant:
(a) une enveloppe (11) de forme générale cylindrique, qui possède une chambre d'entrée supérieure (18) et une chambre de classage inférieure (19), avec un disque annulaire (17) qui sépare la chambre supérieure de la chambre inférieure;
(b) un tamis cylindrique vertical (25) contenu dans la chambre inférieure;
(c) un rotor rotatif (30) monté pour tourner autour d'un axe vertical central à l'intérieur du tamis, ce rotor possédant un corps dont le bas est adjacent à l'extrémité inférieure du tamis cylindrique, le corps ayant une forme qui est de haut en bas de section circulaire transversalement à l'axe et dont le diamètre croît du haut en bas, en laissant ainsi subsister un plus grand espace annulaire en haut, et une entrée annulaire comprise entre le disque annulaire et le haut du corps;
(d) des moyens servant à faire tourner ce rotor.
(e) des pales de rotor (35) qui font saillie dans une diposition rayonnante sur au moins une partie du corps du rotor et qui se prolongent jusqu'à petite distance du tamis sur la hauteur du tamis; et
(f) une sortie (27) de décharge de la pâte qui part de la chambre inférieure en dehors du tamis, caractérisé en ce qu'au moins une cloison (41) de forme sensiblement tronconique, concentrique au corps du rotor (30) s'étend vers le bas à partir de l'entrée annulaire et est adaptée pour diviser le courant de pâte qui entre dans l'entrée annulaire, la cloison formant une ouverture annulaire, en section transversale à l'axe, entre la cloison et le corps du rotor, qui possède sensiblement la même aire de section à l'extrémité d'entrée et au bas de la cloison, et la cloison étant réunie extérieurement aux pales (35) du rotor.
2. Dispositif classeur de pâte rotatif selon la revendication 1, caractérisé en ce que l'ouverture subsistant entre la cloison (41) et le corps du rotor (30) ne contient pas intérieurement de Pales du rotor.
3. Dispositif classeur de pâte rotatif selon la revendication 1 ou la revendication 2, caractérisé en ce qu'une virole d'entrée tronconique (22) est prévue dans la chambre supérieure, cette virole s'élevant sur le disque annulaire, et présentant son plus petit diamètre en haut de l'anneau d'entrée, et en ce que le rotor rotatif (30) possède une portion cône (31) en segment de paraboloïde pour créer une forme approximativement parabo- loïdale.
4. Dispositif classeur de pâte rotatif selon une quelconque des revendications 1 à 3, caractérisé en ce que la hauteur axiale de la cloison (41) est d'environ 20% de la hauteur du tamis cylindrique (25).
5. Dispositif classeur de pâte rotatif selon une quelconque des revendications 1 à 3, caractérisé en ce que de l'eau de dilution est envoyée au tamis cylindrique (25) au-dessous de la cloison (41).
6. Dispositif classeur de pâte rotatif selon la revendication 1, caractérisé en ce que ce rotor (30) possède un corps présentant la forme d'un segment de Paraboloïde.
7. Dispositif classeur de pâte rotatif selon la revendication 6, caractérisé en ce que le corps en forme de segment paraboloïdal du rotor (30) est composé d'une pluralité de segments tronconiques.
8. Dispositif classeur de pâte rotatif selon la revendication 1, caractérisé en ce que ce rotor (30) présente un corps de forme tronconique.
9. Dispositif classeur de pâte rotatif selon une quelconque des revendications 1 à 8, caractérisé en ce qu'il est prévu deux cloisons (41, 42) sensiblement tronconiques, une première cloison (41) concentrique au corps du rotor (30) et descendant à partir de l'entrée annulaire, et une deuxième cloison (42) concentrique au corps du rotor (30) et qui s'étend vers le bas à partir d'au-dessous de la première cloison, les deux cloisons étant positionnées de telle manière que le courant de pâte qui pénètre dans l'entrée annulaire soit divisé en trois parties, une première partie passant à travers un premier espace annulaire compris entre le sommet de la première cloison et le disque annulaire, une deuxième Partie passant à travers un deuxième espace annulaire compris entre la base de la première cloison et le sommet de la deuxième cloison, et une troisième partie passant à travers un troisième espace annulaire compris entre la base de la deuxième cloison et la surface du corps du rotor.
10. Dispositif classeur de pâte rotatif selon la revendication 9, caractérisé en ce que la hauteur axiale de chaque cloison (41, 42) est d'environ 20% de la hauteur du tamis cylindrique (25).
11. Dispositif classeur de pâte rotatif selon la revendication 9 ou la revendication 10, caractérisé en ce que de l'eau de dilution est envoyée au tamis cylindrique (25) au-dessous des cloisons (41,42).
12. Dispositif classeur de pâte rotatif selon la revendication 1, caractérisé en ce qu'il est prévu trois cloisons (41, 42, 70) de forme sensiblement tronconique, qui s'étendent vers le bas l'une au-dessous de l'autre.
13. Dispositif classeur de pâte rotatif selon la revendication 12, caractérisé en ce que la hauteur réelle de chaque cloison (41, 42, 70) est d'environ 20% de la hauteur du tamis cylindrique (25).
14. Dispositif classeur de pâte rotatif selon la revendication 1, caractérisé en ce qu'il est prévu une pluralité (41, 42, 70) de cloisons de forme sensiblement tronconique, s'étendant vers le bas l'une au-dessous de l'autre.
15. Rotor rotatif (30) adapté pour tourner à l'intérieur d'un tamis cylindrique (25) appartenant à un dispositif classeur de pâte (10) du type vertical à pression, où ce rotor (30) comprend un corps ayant de haut en bas une forme de section circulaire transversalement à l'axe du haut en bas, dont le diamètre croît du haut en bas, des pales de rotor (35) étant prévues dans une disposition rayonnante en saillie sur au moins une partie du corps du rotor et qui se prolongent jusqu' à une petite distance du tamis (25) sur la hauteur du tamis, caractérisé en ce qu'il est prévu au moins une cloison (41) de forme sensiblement tronconique, concentrique au corps du rotor (30) et s'étendant vers le bas à partir du sommet du rotor, la cloison étant adaptée pour diviser le courant de pâte et former une ouverture de section annulaire transversalement à l'axe entre la cloison et le corps du rotor, cette ouverture ayant sensiblement la même aire de section à l'extrémité d'entrée et à la base de la cloison, la cloison étant réunie extérieurement aux pales (35) du rotor.
16. Rotor rotatif selon la revendication 15, caractérisé en ce que la hauteur axiale de la cloison (41) est d'environ 20% de la hauteur du tamis cylindrique (25).
17. Rotor rotatif selon la revendication 15, caractérisé en ce qu'il est prévu une pluralité de cloisons (41, 42, 70) de forme sensiblement tronconique qui s'étendent vers le bas l'une au-dessous de l'autre.
18. Procédé pour classer une pâte dans un dispositif classeur de pâte rotatif (10) du type vertical à pression, qui comprend une enveloppe (11) de forme générale cylindrique ayant une chambre d'entrée supérieure (18) et une chambre de classage inférieure (19), avec un disque annulaire (17) qui sépare la chambre supérieure de la chambre inférieure, un tamis cylindrique vertical (25) contenu dans la chambre inférieure, un rotor rotatif (30) monté pour tourner autour d'un axe vertical central à l'intérieur du tamis, ce rotor possédant un corps dont le bas est adjacent à l'extrémité inférieure du tamis cylindrique, le corps ayant une forme qui est de haut en bas de section circulaire transversalement à l'axe et dont le diamètre croît du haut en bas, en laissant ainsi subsister un plus grand espace annulaire en haut, et une entrée annulaire entre le disque annulaire et le sommet du corps, des moyens servant à faire tourner ce rotor, des pales d'un rotor (35) qui font saillie dans une disposition rayonnante sur au moins une portion du corps du rotor et se prolongent jusqu'à petite distance du tamis sur la hauteur du tamis, et une sortie (27) de décharge de la pâte partant de la chambre inférieure à l'extérieur du classeur, dans lequel la pâte qui pénètre dans l'entrée annulaire est entraînée en rotation par les pales du rotor, s'écoule en descendant le long du tamis et se mélange à de l'eau de dilution, la pâte passant à travers le tamis sensiblement sur toute la hauteur du tamis et sortant à travers la décharge de pâte, caractérisé en ce que le procédé consiste à diviser le courant de pâte qui pénètre par l'entrée annulaire en une pluralité de parties avant que la pâte ne soit entraînée en rotation par les pales du rotor, à diriger chacune des parties vers une zone du tamis situé à une hauteur différente, de telle manière que la vitesse de la pâte qui descend le long du tamis soit sensiblement constante, et à ajouter de l'eau de dilution à la pâte en d'autres zones de la hauteur du tamis, au-dessous des zones où les parties sont dirigées, de telle manière que la vitesse de la pâte en mouvement descendant vers le bas du tamis reste sensiblement constante.
19. Procédé selon la revendication 12, caractérisé en ce que le courant de pâte est divisé en une pluralité de parties égales, la première partie étant dirigée vers la partie haute du tamis et les parties restantes étant dirigées vers des zones espacées de distances qui représentent environ 20% de la hauteur du tamis.
EP84308039A 1983-12-12 1984-11-20 Epurateur rotatif du type vertical, sous pression, ayant une alimentation en pulpe à différentes positions, axialement espacées Expired - Lifetime EP0145365B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84308039T ATE58403T1 (de) 1983-12-12 1984-11-20 Rundsieb von vertikalem ueberdrucktyp, mit stockzufuhr auf verschiedenen, axial voneinander entfernten positionen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US56024883A 1983-12-12 1983-12-12
US560248 1995-11-21

Publications (3)

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EP0145365A2 EP0145365A2 (fr) 1985-06-19
EP0145365A3 EP0145365A3 (en) 1987-04-01
EP0145365B1 true EP0145365B1 (fr) 1990-11-14

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ID=24236977

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EP84308039A Expired - Lifetime EP0145365B1 (fr) 1983-12-12 1984-11-20 Epurateur rotatif du type vertical, sous pression, ayant une alimentation en pulpe à différentes positions, axialement espacées

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EP (1) EP0145365B1 (fr)
AT (1) ATE58403T1 (fr)
CA (1) CA1238604A (fr)
DE (1) DE3483601D1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI83892C (fi) * 1989-06-05 1991-09-10 Tampella Oy Ab Trycksil.
US5075001A (en) * 1989-07-13 1991-12-24 Taylor James W Method and apparatus for recovering fibrous material from a paper/pulp process water stream
SE511786C2 (sv) 1998-03-06 1999-11-22 Sunds Defibrator Ind Ab Silanordning med två silkammare för separering av fibersuspensioner
JP3435346B2 (ja) * 1998-04-16 2003-08-11 相川鉄工株式会社 スクリーン装置
AT408772B (de) * 2000-02-03 2002-03-25 Andritz Ag Maschf Sortierer zur reinigung einer faserstoffsuspension
AT413390B (de) * 2003-03-27 2006-02-15 Andritz Ag Maschf Sortierer zur reinigung einer fasersuspension
AT413391B (de) * 2003-03-27 2006-02-15 Andritz Ag Maschf Sortierer zur reinigung einer fasersuspension

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1639273A (en) * 1925-04-01 1927-08-16 Improved Paper Machinery Compa Screen
US3400820A (en) * 1965-03-30 1968-09-10 Bird Machine Co Screening apparatus with rotary pulsing member
DE2712749A1 (de) * 1977-03-23 1979-02-08 Finckh Maschf Sortierer zum sichten von fasersuspensionen
US4268381A (en) * 1979-05-03 1981-05-19 Uniweld Inc. Rotary pulp screening device of the vertical pressure type

Also Published As

Publication number Publication date
CA1238604A (fr) 1988-06-28
DE3483601D1 (de) 1990-12-20
EP0145365A3 (en) 1987-04-01
ATE58403T1 (de) 1990-11-15
EP0145365A2 (fr) 1985-06-19

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