EP0117716B1 - Apparatus for pulping paper, and a rotor therefor - Google Patents

Apparatus for pulping paper, and a rotor therefor Download PDF

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Publication number
EP0117716B1
EP0117716B1 EP19840301139 EP84301139A EP0117716B1 EP 0117716 B1 EP0117716 B1 EP 0117716B1 EP 19840301139 EP19840301139 EP 19840301139 EP 84301139 A EP84301139 A EP 84301139A EP 0117716 B1 EP0117716 B1 EP 0117716B1
Authority
EP
European Patent Office
Prior art keywords
rotor
stock
pulp
vane
screw
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
Application number
EP19840301139
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0117716A3 (en
EP0117716A2 (en
Inventor
David E. Chupka
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.)
BLACK CLAWSON (FRANCE) S.A.
Black Clawson Co
Original Assignee
Black Clawson (France) SA
Black Clawson Co
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
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Application filed by Black Clawson (France) SA, Black Clawson Co filed Critical Black Clawson (France) SA
Publication of EP0117716A2 publication Critical patent/EP0117716A2/en
Publication of EP0117716A3 publication Critical patent/EP0117716A3/en
Application granted granted Critical
Publication of EP0117716B1 publication Critical patent/EP0117716B1/en
Expired legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/30—Defibrating by other means
    • D21B1/34—Kneading or mixing; Pulpers
    • D21B1/345—Pulpers
    • D21B1/347—Rotor assemblies

Definitions

  • This invention relates to apparatus for pulping paper making stock at relatively high consistencies, and more particularly to paper pulping apparatus in which a vaned rotor is utilized to circulate the stock within a tub.
  • Paper pulping apparatus typically includes a tub having a bottom wall and a cylindrical side wall extending upwardly therefrom, a vaned rotor centrally mounted on the bottom wall for rotation within the tub, and a screen or valve means located in or near the bottom wall to provide means for removal of the pulped paper stock.
  • the rotor vanes include leading faces which are shaped and sized to contact stock near the bottom wall of the tub and propel it radially outwardly from the rotor against the side wall, which directs the stock upwardly.
  • the rising stock flows to the center of the tub and then downwardly toward the rotating vanes.
  • the stock is caused to flow in a generally circular pattern, and the reduction in size of the individual particles of paper stock is due largely if not exclusively to the high sheer forces between particles of stock created by this flow pattern.
  • rotors In order to perform a pulping process upon stock having a consistency in excess of about 10%, special rotors have been developed.
  • a high consistency pulping apparatus having a rotor with a vertically oriented and axially aligned feeding screw.
  • the rotor includes vanes in the form of circumferentially-extending members with a half-crescent shape which are disposed about the periphery of a disk-shaped plate.
  • the feeding screw is mounted in the center of the plate and includes a cylindrically-shaped body having a base which is spaced from the rotor vanes, and a helical screw flight which extends along the body and terminates at a squared end above the disk-sha.,,-v.3d plate supporting the vanes.
  • the feeding screw When rotated in a tub containing stock at 12-13% consistency, the feeding screw guides the stock downwardly to the region of the rotor vanes which then propel it outwardly against the walls of the tub.
  • the higher consistency stock climbs the walls of the tub, and baffles are employed to direct the pulp downwardly toward the tub center.
  • a high consistency pulping apparatus having a rotor which minimizes the likelihood of cavitation.
  • the rotor provides means for guiding the high density stock in a smooth and uninterrupted path from a location adjacent the center of the rotor to the working faces of the vanes without the stock becoming wedged between the screw flight and rotor vane.
  • such a rotor is characterised by said conical body having a base with an outer periphery immediately adjacent to the said root portions such that pulp guided downwardly by said screw flight means is urged outwardly by said conical body to engage said root portions and be propelled by said vane means.
  • the invention also includes apparatus for pulping paper making stock at high consistencies of the type having a tub having a bottom wall and a cylindrical side wall extending upwardly therefrom, a rotor body mounted for rotation on a vertical axis in the center of said bottom wall, vane means extending generally radially outwardly from said rotor body at root portions thereof and constructed to impel high consistency pulp stock toward said side wall, and a feed screw having a conical body mounted centrally of said rotor body and extending upwardly therefrom and screw flight means extending along said conical body for guiding pulp downwardly to said vanes, characterised by said conical body having a base with an outer periphery immediately adjacent to said root portions such that pulp guided downwardly by said screw flight means is guided outwardly to engage said root portions and be propelled by said vane means.
  • the present invention provides an apparatus for pulping paper making stock which is capable of pulping relatively high consistency stock, that is, stock in a range of approximately 10-25% solids, in a manner that creates the necessary circular flow patterns to generate the high shear forces between paper particles in order to perform the pulping operation in a minimum amount of time.
  • Another advantage of the invention is that it includes a rotor that is designed to minimize the likelihood of cavitation and the likelihood of stock collecting on the rotor to obstruct the downward and outward flow of stock to the vanes.
  • the conical body of the feed screw includes a base sized such that its periphery is adjacent the root portions of the rotor vanes.
  • the trailing end of the screw flight blends into the working face of a vane to form a continuous surface therewith.
  • the flight of the feed screw includes a trailing edge which tapers in width and terminates at the periphery of the base adjacent a vane root.
  • the present invention preferably includes a tub having a bottom wall and a cylindrical side wall extending upwardly therefrom, and the rotor body is centrally mounted on the bottom wall for rotation in a vertical axis.
  • the feed screw is sized such that, when mounted on the rotor body, its height above the bottom wall of the pulping tub approximates the intended depth of the stock within the tub.
  • the rotor of the preferred embodiment causes the stock within the tub to flow in the previously described circular pattern such that the level of the stock at the center of the tub is below the level of the stock at the side wall, thereby exposing the tip of the feed screw.
  • the feed screw and stock are in this configuration, the feed screw provides a means of escape for any air which is present in the vicinity of the vanes, thus further reducing the likelihood of cavitation.
  • the invention can utilize prior art rotors which previously were capable of functioning only in low consistency pulping operations.
  • the feed screw can be retrofitted to a prior art rotor, such as the rotor disclosed in the Couture U.S. Patent No. 3,889,885.
  • a prior art rotor such as the rotor disclosed in the Couture U.S. Patent No. 3,889,885.
  • an object of the present invention to provide an apparatus for pulping paper making stock at high consistencies which minimizes the likelihood of cavitation; an apparatus which provides a continuous path along which stock may travel from an upper portion of the pulping tub to the outer tip of the vane; and an apparatus for pulping high consistency stock which can be made by modifying low consistency systems.
  • the pulper shown in Figure 1 includes a tub 10 having a cylindrical upper wall 12 and a bottom wall comprising a plane center section 14 surrounded by a frusto-conical portion 16.
  • the center section 14 includes a perforated bed plate 18 for draining the pulped paper stock from the tub 10 after the completion of the pulping operation.
  • the tub 10 is mounted on supports 20 above a gear drive 22 which is directly driven by a motor 24.
  • the cylindrical side wall 12 includes baffles 26 which direct pulp stock flowing upwardly against the wall outwardly toward the center of the tub 10.
  • a rotor, generally designated 28, is mounted in the center of the perforated bed plate 18 and is driven by the motor 24 and gear drive 22.
  • the rotor 28 includes a rotor body 30 having a cover plate 32 and vane ring 34.
  • the vane ring 34 supports a plurality of vanes 36, alternate ones of which are of increased thickness and function as pumping vanes 38.
  • the rotor 28 as described thus far is of a type well-known in the art and is commonly used in pulping devices for defibering stock at between 5% and 8% consistency.
  • the structure and cooperation of the rotor 28 with the perforated bed plate 18 are described more fully in the Couture U.S. Patent No. 3,889,885, commonly assigned, the disclosure of which is incorporated herein by reference.
  • the rotor 28 of the present invention differs significantly from prior art rotors in that it includes a feed screw, generally designated 40.
  • the feed screw 40 includes a conical body 42 which is concentric with the rotor body 30, and extends upwardly therefrom.
  • the rotor 28 may be cast as a single unit, or the feed screw 40 and rotor body 30 may be fabricated separately and then joined together.
  • the conical body 42 includes a rounded top 44 and a circular base 46 which extends to the root portions 48 of the pumping vanes 38.
  • the feed screw 40 includes helical screw flights 50, 52 which intertwine along the length of the conical body 42.
  • Each of the screw flights 50, 52 is ribbon-shaped and includes a trailing portion 54 which terminates at the base 46 of the conical body 42 adjacent the root 48 of a vane 38.
  • the trailing portions 54 are twisted so that their undersides 56 are contiguous with the face 58 of the pumping vane 38 so as to form a continuous surface therewith.
  • the tub 10 Prior to operation, the tub 10 is filled with paper making stock 60 which preferably is at a consistency of between 12% and 25% solids. The level of the stock within the tub 10 should approximate the height of the rounded top 44 of the feed screw 40 above the center section 14.
  • the rotor 28 is rotated in a counterclockwise direction, indicated by arrows A shows in Figures 2 and 3.
  • the helical screw flights 50, 52 of the feed screw 40 draw the stock 60 downwardly toward the rotor body 30.
  • the stock is urged outwardly by the increasing diameter of the conical body 42.
  • the stock travels in a downward helical path of increasing diameter, as indicated by arrows B in Figure 3.
  • the pulp Once the pulp has contacted the vanes 38, it is propelled outwardly in a generally radial direction toward the frusto-conical portion 16, and then upwardly against the wall 12 to the top of the tub 10.
  • the rising pulp encounters the baffles 26 which act to direct the pulp downwardly and inwardly toward the center of the tube where it again is directed toward the rotor body 30 by the feed screw 40.
  • the baffles 26 Due to the high consistency of the stock 60, the depth of the upwardly rising stock at the periphery of the tub 10 is greater than that at the tub center. Therefore, during operation, the rounded top 44 becomes exposed and the feed screw provides a channel or conduit for the escape of air from the vicinity of the rotor body 30, thereby further reducing the likelihood of cavitation.
  • the apparatus can be operated such that the depth of stock in the tub may exceed the height of the top 44, in which case the feed screw 40 will convey air to the upper level of the stock, where it will escape through the remaining stock to the atmosphere.
  • the conical body 42, the flights 50, 52 and the vane faces 58 combine to provide a substantially continuous pathway which positively guides the stock from the top of the feed screw 40 to the outer tips of the rotor vane faces 58. Since the trailing portions 54 of the screw flights blend into the vane faces 58, there are no pockets or gaps which may collect pulp or form voids, so that the generated flow of pulp is much smoother than with prior art rotors having feed screws whose flights are not contiguous with the vane roots 48.
  • the rotor 28A shown in Figure 4 includes a rotor body 30A in which a feed screw 40A has been attached to the cover plate 32A by a bolted flange 62 which extends outwardly from the ps'iphery base 46A of the conical body 42A.
  • the design of the rotor 28A differs from the rotor 28 shown in Figures 1-3 in that the periphery of the base 46A is not immediately adjacent the vane roots 48A of the pumping vanes 38A.
  • trailing portions 54A of the screw flights 50A, 52A are not contiguous with the vane roots 48A. Rather, the trailing portions 54A taper in width until they terminate at a point 64 located at the base 46A of the conical body 42A.
  • the feed screw 40A cannot be fabricated easily such that its trailing portions 54A blend into the vane faces 58A of the pre-existing rotor 28A, it is desirable to taper the width of the trailing portions to a point 64 to reduce the likelihood that pulp stock will become wedged in the space between the underside of the trailing portions and the cover plate 32A or other portions of the rotor body 30A.
  • the feed screw 40A will still impart a downward and outward motion to the pulp stock within a tub which directs it to the faces 58A of the vanes 38A. This motion minimizes the likelihood that pump stock will collect or stagnate in the central area of the rotor body 30A and not flow to the pumping vanes 38A.
  • a rotor 28B includes a rotor body 30B having four vanes 368, each of which includes a pumping face 588.
  • the vanes 36B are mounted on a generally frusto-conical shaped vane ring 348.
  • Rotor bodies 30B of this type are generally used in pulping operations where the consistency of the pulp stock is between 5% and 8% solids.
  • a feed screw 40B is mounted to the central portion of the rotor body 30B and includes screw flights 50B, 52B which intertwine about the conical body 42B and terminate immediately adjacent the vane roots 48B.
  • Each of the trailing portions 548 of the screw flights 50B, 52B taper in width in a manner similar to that of the embodiment of Figure 4 and terminate at a point 64B on the base 468 of the conical body 428.
  • the outer edges 66 of the trailing portions 548 combine with the upper edges 68 of the pumping faces 58B to form continuous edges therewith.
  • the location of the trailing portions and the base 468 of the conical body 42B combine to provide a continuous path for the paper stock which guides the stock directly to the pumping faces 58B of the vanes 36B.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
EP19840301139 1983-02-28 1984-02-22 Apparatus for pulping paper, and a rotor therefor Expired EP0117716B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US47084783A 1983-02-28 1983-02-28
US470847 1983-02-28

Publications (3)

Publication Number Publication Date
EP0117716A2 EP0117716A2 (en) 1984-09-05
EP0117716A3 EP0117716A3 (en) 1985-05-29
EP0117716B1 true EP0117716B1 (en) 1988-09-07

Family

ID=23869305

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840301139 Expired EP0117716B1 (en) 1983-02-28 1984-02-22 Apparatus for pulping paper, and a rotor therefor

Country Status (6)

Country Link
EP (1) EP0117716B1 (es)
JP (1) JPS59199895A (es)
BR (1) BR8400776A (es)
CA (1) CA1242346A (es)
DE (1) DE3473894D1 (es)
ES (1) ES530083A0 (es)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10821408B2 (en) 2015-10-30 2020-11-03 Lenzing Aktiengesellschaft High-concentration mixer for producing a cellulose suspension having a high cellulose concentration

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1228762A (en) * 1983-05-18 1987-11-03 Joseph W. Couture Pulping apparatus and method
DE3743247A1 (de) * 1987-12-19 1989-06-29 Escher Wyss Gmbh Pulper mit hoher aufloeseeffizienz
SE509293C2 (sv) 1997-04-29 1999-01-11 Cellwood Machinery Ab Anordning vid massaupplösare
ITVI20020048A1 (it) * 2002-03-19 2003-09-19 Comer Spa Propulsore per l'agitazione di sospensioni di solidi all'interno di una vasca di trattamento
GB0703053D0 (en) * 2007-02-16 2007-03-28 Ici Plc Apparatus for and Methods of Mixing and Dispensing Samples
CN101708819B (zh) * 2008-12-03 2012-07-04 鞍钢集团矿业公司 矿浆分配器
DE102010005596B4 (de) 2010-01-25 2015-11-05 Epcos Ag Elektroakustischer Wandler mit verringerten Verlusten durch transversale Emission und verbesserter Performance durch Unterdrückung transversaler Moden
DE102011082976A1 (de) 2011-09-19 2013-03-21 Günter Betz Vorrichtung zum Aufschlagen (zerkleinern, zerfasern, auflösen, aufbereiten) von Altpapieren und Zellstoffen in einem Pulper (Stofflöser)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3171606A (en) * 1962-06-06 1965-03-02 Ed Jones Corp Circulating and disintegrating rotor for pulping apparatus
GB1176412A (en) * 1967-01-26 1970-01-01 Bolton Emerson Improvements in and relating to an apparatus and method for Pulping and Defibering
JPS5225104A (en) * 1975-08-14 1977-02-24 Bolton Emerson Pulp making method
DE2542065A1 (de) * 1975-09-20 1977-03-24 Bolton Emerson Verfahren zum zerfasern und verfeinern der fasern insbesondere schwer auffaserbarer materialien sowie zerfaserer zur durchfuehrung des verfahrens
DE2917814C2 (de) * 1979-05-03 1983-12-08 J.M. Voith Gmbh, 7920 Heidenheim Stofflöser zur Herstellung von Papierstoffsuspensionen
DE3027044C2 (de) * 1980-07-17 1982-12-16 J.M. Voith Gmbh, 7920 Heidenheim Rotor für einen Stofflöser

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10821408B2 (en) 2015-10-30 2020-11-03 Lenzing Aktiengesellschaft High-concentration mixer for producing a cellulose suspension having a high cellulose concentration

Also Published As

Publication number Publication date
DE3473894D1 (en) 1988-10-13
BR8400776A (pt) 1984-10-02
CA1242346A (en) 1988-09-27
EP0117716A3 (en) 1985-05-29
JPS59199895A (ja) 1984-11-13
ES8503050A1 (es) 1985-02-01
JPH055958B2 (es) 1993-01-25
EP0117716A2 (en) 1984-09-05
ES530083A0 (es) 1985-02-01

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