US3589521A - Device for cleaning of screens in cellulose digesters - Google Patents

Device for cleaning of screens in cellulose digesters Download PDF

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Publication number
US3589521A
US3589521A US759632A US3589521DA US3589521A US 3589521 A US3589521 A US 3589521A US 759632 A US759632 A US 759632A US 3589521D A US3589521D A US 3589521DA US 3589521 A US3589521 A US 3589521A
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United States
Prior art keywords
screen
cover plate
cleaning liquid
compartment
conduit
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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
US759632A
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English (en)
Inventor
Johan C F C Richter
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.)
Metso Fiber Karlstad AB
Original Assignee
Kamyr AB
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Filing date
Publication date
Application filed by Kamyr AB filed Critical Kamyr AB
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Publication of US3589521A publication Critical patent/US3589521A/en
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C7/00—Digesters
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/32—Washing wire-cloths or felts

Definitions

  • Tushin Att0rneyCushman, Darby and Cushman ABSTRACT Screens inserted in the shell ofa continuous cellulose digester are cleaned by a liquid under high pressure pumped through a sector of the screen during the normal operation of the digester and while the rest of the sd for drawing off digesting liquor from the fibrous material in the digester.
  • the cleaning liquid passes the screen in the opposite direction to the digesting liquor and works loose fibers wedged into the slits of the screen.
  • On the pulp side of the screen the sector being cleaned is blinded off by a turning cover plate, and the space back of screen is divided into sector-shaped compartments.
  • a conduit for circulating cleaning liquid is connected to the space within the sealing edge of the cover plate and to the opposite compartment.
  • the invention relates to a device for cleaning of screens inserted in containers for treatments, particularly digestion, of finely comminuted cellulosic material, and serving for straining off liquid from the cellulosic material.
  • a screen-cleaning device of the kind comprising a movable cover plate arranged on the fiber material side of the screen, which cover plate has an edge surrounding and sealing off a portion of the face of said screen, a conduit for cleaning liquid being connected to the space between said screen part and said cover plate.
  • the object of the present invention is to improve screencleaning devices of the above-mentioned kind so as to make them more efficient.
  • a chamber back of the screen is divided up into compartments separated from each other and connected to individual conduits.
  • the cleaning liquid flow can be made independent of the function of the screen and can take plate without disturbing the same.
  • cleaning liquid may be forced through the screen with a considerably higher pressure than the pressure of the container, so that the force exerted by the cleaning liquid upon the particles clogging the screen apertures can be made greater than the force by which they have been wedged into the same during the previous screening period, and consequently said particles can be worked loose more easily.
  • the cleaning liquid can be held separated from the liquid mixed with the cellulosic material, involving the possibility of using any suitable kind of cleaning liquid, e.g. a chemically active liquid, which dissolves heavily adhering deposits upon the screen and which is of such a kind that it should not be mixed into the liquid treating the cellulosic material.
  • a suitable kind of cleaning liquid e.g. a chemically active liquid, which dissolves heavily adhering deposits upon the screen and which is of such a kind that it should not be mixed into the liquid treating the cellulosic material.
  • a chemically active liquid which dissolves heavily adhering deposits upon the screen and which is of such a kind that it should not be mixed into the liquid treating the cellulosic material.
  • FIG. 1 is a vertical sectional view of the screen according to the invention
  • FIG. 2 is a horizontal sectional view of the screen
  • FIG. 3 is an elevational view thereof taken from the right-hand side in FIG. l
  • FIG. 4 is a vertical sectional view taken from the line lV-IV of FIG. ll.
  • the number 11 designates the cylindrical shell of an upright cylindrical cellulose digester adapted for carrying out continuous digester of cellulosic material, such as wood chips.
  • cellulosic material such as wood chips.
  • the wood chips should be relieved of used liquor and reaction products, such as black liquor with an admixture of prehydrolysate, there are inserted in the digester shell a number of screens, only one thereof being shown in the drawings.
  • the shown screen is composed of a number of parallel, closely set vertical screen rods 13 and a screen chamber 15 back thereof.
  • the latter is formed by a back wall 17 and a cylindrical flange 19 having a recess against which the screen rods rest with their ends and are held evenly spaced so that their sides facing the interior of the digester form a flat circular surface in which there are parallel slits of a suitable width for retaining the chips and letting the digesting liquor through.
  • These screening rods and the chamber form a unit which is inserted in an annular flange 21 integral with the digester shell and is attached thereto by means of a flat annular flange 23 in such a position that said flat screen surface is flush with the digester wall 11 or somewhat retracted.
  • a half-circular cover plate 25 or eyelid attached to a hollow shaft 27 extending centrally through the screen and its chamber.
  • Said shaft is journaled in a central bearing sleeve 29 integral with the backwall 17 of the screen chamber and extending therefrom in the forward as well as in the backward direction.
  • the shaft 27 is sealed to said bearing sleeve by means of a stuffing box 31.
  • Attached to the backward end of the shaft is a handle 33 or other operating means whereby the shaft and the cover plate 25 attached thereto can be turned and set in any desired angular position.
  • Normal positions are the position shown and the diametrically opposite position obtained by a turning movement of In both of said positions the straight edge 35 of the cover plate is vertical and parallel to the screen rods 13, so that the cover plate offers the least possible resistance to movement of the chips in the length direction of the digester and so that the exposed slits between the screen rods are swept in their entire lengths by the chips, a certain automatic cleaning effect being obtained.
  • the cover plate 25 is somewhat convex or domed inwardly but its straight edge 35 as well as its half-circular edge 37 fit closely to the screen so that a cavity 9 closed off from the digester is formed on the back side of the cover plate.
  • Such liquid as enters the cavity 39 from the screen chamber is let out in the described path.
  • the screen chamber 15 is divided upon into two compartments 53, 55, completely separated from each other.
  • the left-hand compartment 53 communicates via a conduit 57 extending through the backwall 17, with a manifold 59
  • the right-hand compartment of each screen communicates over a conduit 61 with a manifold 63.
  • the manifold 59 can be connected either to a main discharge conduit 67 for extracted digesting liquor and/or to a scavenging liquid conduit 69.
  • the manifold 63 can be connected by means of a three-way valve 71 either to the conduit 67 or the conduit 69.
  • the two three-way valves should always connect the manifolds differently, and therefore they are preferably mechanically coupled so as to be reset simultaneously and in a fixed relation.
  • the conduit 69 is connected to the manifold 49 over a motor'driven pump 73, so that said pump can maintain a circulation of liquid which when the cover plate 25 takes the position shown runs in the loop 73, 69, 65, 59, 57, 53, 39, 41, 43, 45, 47, 49, 73.
  • Cleaning liquid which may be strong sodium lye, is introduced into said loop from a supply tank 75. When the cleaning liquid has become too contaminated with dissolved impurities, it is drained through conduit 79 by opening valve 77. During said cleaning of one screen half the other can be used for withdrawing digesting liquor which is discharged through 55, 61, 63, 71, 67.
  • the cover plate blind merely a small sector of the screen; then the screen chamber must be divided up into a greater number of chambers having a correspondingly smaller angular extension.
  • the cover plate forms a sector of 120, the screen chamber must be divided in three compartments by means of radial partitions.
  • Apparatus for cleaning of screens inserted in containers for treatment of finely comminuted eellulosic material and serving for drawing off liquid from the eellulosic material comprising: a cover plate covering a portion of the screen; means for moving the cover plate over the screen on the eellulosic material side thereof, said cover plate having an edge closely applied against the screen and surrounding a part of its surface and defining a cavity with said surface; a cleaning liquid discharge conduit extending through the cover plate and opening out into said cavity; means defining a chamber located on the opposite side of the screen from the cover plate; partition means dividing said chamber into separate compartments, said partition means having edges adjacent said screen opposite said cover plate which cooperate with the edge of said cover plate to maintain said cavity in communication with a given compartment, and a separate conduit connected to each compartment for delivery thereto a stream of cleaning liquid when said cavity is in communication with said given compartment whereby cleaning liquid will flow through said screen from said given compartment to said cavity and out through said discharge conduit.
  • Apparatus as in claim 1 including valve means connected to said separate conduits, means connected to said valve means for supplying cleaning liquid under pressure, each valve means also connected to a main discharge conduit, said valve means operative such that with one valve in position to connect its associated compartment conduit with said cleaning liquid the other valves are positioned to connect their associated compartment conduits with said main discharge conduitv 4.
  • Apparatus as in claim 1 including a supply tank of cleaning liquid, means for supplying said cleaning liquid under pressure from said supply tank to one of said separate conduits when the compartment associated with that separate conduit is covered by said cover plate whereby cleaning liquid flows through said one conduit into said compartment, then through said screen into said cavity and then through said cleaning liquid discharge conduit.

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  • Paper (AREA)
US759632A 1967-09-15 1968-09-13 Device for cleaning of screens in cellulose digesters Expired - Lifetime US3589521A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE12729/67A SE307287B (sv) 1967-09-15 1967-09-15

Publications (1)

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US3589521A true US3589521A (en) 1971-06-29

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Application Number Title Priority Date Filing Date
US759632A Expired - Lifetime US3589521A (en) 1967-09-15 1968-09-13 Device for cleaning of screens in cellulose digesters

Country Status (7)

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US (1) US3589521A (sv)
BR (1) BR6802320D0 (sv)
DE (1) DE1792528B1 (sv)
FI (1) FI47393C (sv)
FR (1) FR1587735A (sv)
NO (1) NO120301B (sv)
SE (1) SE307287B (sv)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3755072A (en) * 1970-10-23 1973-08-28 Kamyr Ab Strainer device for cellulose digester
US3971715A (en) * 1973-02-27 1976-07-27 Albert Wehner Device for sieving, sorting, filtering and the like
US3979289A (en) * 1972-11-08 1976-09-07 Water Pollution Control Corporation Filtration method
FR2351208A1 (fr) * 1976-05-11 1977-12-09 Kamyr Inc Procede et appareil pour le traitement des matieres en fibres
US4167482A (en) * 1976-10-11 1979-09-11 Mueller Hans Filtering method and apparatus
US4219420A (en) * 1978-03-02 1980-08-26 Chemap Ag Arrangement for and a process of filtering a contaminated medium
US4284120A (en) * 1976-09-03 1981-08-18 Gloeersen Stig Method and device for transfer of fiber materials transportable by liquids
US4995944A (en) * 1988-09-16 1991-02-26 Dearborn Chemical Company Ltd. Controlling deposits on paper machine felts using cationic polymer and cationic surfactant mixture
US5223097A (en) * 1986-01-09 1993-06-29 W. R. Grace Ab Method for controlling pitch on a paper-making machine
US5565061A (en) * 1994-06-14 1996-10-15 Salminen; Reijo Method and apparatus for removing scales deposited on the strainer of a pulp digester
US5626720A (en) * 1986-01-09 1997-05-06 W.R. Grace & Co.-Conn. Method for controlling pitch on a papermaking machine
WO1998033603A1 (en) * 1997-02-03 1998-08-06 Meurer Industries, Inc. Universal method of and apparatus for screening debris
US6120647A (en) * 1998-01-26 2000-09-19 Ahlstrom Machinery Inc. Simplified liquid removal system for a cellulose pulp digester
US20020129911A1 (en) * 2000-10-16 2002-09-19 Marcoccia Bruno S. Process and configuration for providing external upflow/internal downflow in a continuous digester
US11001967B1 (en) 2017-09-22 2021-05-11 Farnsworth Coleman, Sr. Pulp-digester screen cleaner

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3360907A (en) * 1963-10-17 1968-01-02 Southwest Res Inst Apparatus for cleaning filters
US3434920A (en) * 1965-10-07 1969-03-25 Frank B K Green Apparatus for continuous digesting

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3360907A (en) * 1963-10-17 1968-01-02 Southwest Res Inst Apparatus for cleaning filters
US3434920A (en) * 1965-10-07 1969-03-25 Frank B K Green Apparatus for continuous digesting

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3755072A (en) * 1970-10-23 1973-08-28 Kamyr Ab Strainer device for cellulose digester
US3979289A (en) * 1972-11-08 1976-09-07 Water Pollution Control Corporation Filtration method
US3971715A (en) * 1973-02-27 1976-07-27 Albert Wehner Device for sieving, sorting, filtering and the like
FR2351208A1 (fr) * 1976-05-11 1977-12-09 Kamyr Inc Procede et appareil pour le traitement des matieres en fibres
US4284120A (en) * 1976-09-03 1981-08-18 Gloeersen Stig Method and device for transfer of fiber materials transportable by liquids
US4167482A (en) * 1976-10-11 1979-09-11 Mueller Hans Filtering method and apparatus
US4219420A (en) * 1978-03-02 1980-08-26 Chemap Ag Arrangement for and a process of filtering a contaminated medium
US5223097A (en) * 1986-01-09 1993-06-29 W. R. Grace Ab Method for controlling pitch on a paper-making machine
US5626720A (en) * 1986-01-09 1997-05-06 W.R. Grace & Co.-Conn. Method for controlling pitch on a papermaking machine
US4995944A (en) * 1988-09-16 1991-02-26 Dearborn Chemical Company Ltd. Controlling deposits on paper machine felts using cationic polymer and cationic surfactant mixture
US5565061A (en) * 1994-06-14 1996-10-15 Salminen; Reijo Method and apparatus for removing scales deposited on the strainer of a pulp digester
WO1998033603A1 (en) * 1997-02-03 1998-08-06 Meurer Industries, Inc. Universal method of and apparatus for screening debris
US6010013A (en) * 1997-02-03 2000-01-04 Meurer Industries, Inc. Universal method of and apparatus for screening debris
US6120647A (en) * 1998-01-26 2000-09-19 Ahlstrom Machinery Inc. Simplified liquid removal system for a cellulose pulp digester
US20020129911A1 (en) * 2000-10-16 2002-09-19 Marcoccia Bruno S. Process and configuration for providing external upflow/internal downflow in a continuous digester
US11001967B1 (en) 2017-09-22 2021-05-11 Farnsworth Coleman, Sr. Pulp-digester screen cleaner

Also Published As

Publication number Publication date
NO120301B (sv) 1970-09-28
DE1792528B1 (de) 1971-11-18
SE307287B (sv) 1968-12-23
FI47393B (sv) 1973-07-31
BR6802320D0 (pt) 1973-01-09
FR1587735A (sv) 1970-03-27
FI47393C (sv) 1973-11-12

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