WO1990012919A1 - Dewatering device - Google Patents

Dewatering device Download PDF

Info

Publication number
WO1990012919A1
WO1990012919A1 PCT/SE1990/000168 SE9000168W WO9012919A1 WO 1990012919 A1 WO1990012919 A1 WO 1990012919A1 SE 9000168 W SE9000168 W SE 9000168W WO 9012919 A1 WO9012919 A1 WO 9012919A1
Authority
WO
WIPO (PCT)
Prior art keywords
screening cylinder
pulp
screw thread
dewatering
cylinder
Prior art date
Application number
PCT/SE1990/000168
Other languages
French (fr)
Inventor
Ebbe HODÉN
Original Assignee
Sunds Defibrator Industries Aktiebolag
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 Sunds Defibrator Industries Aktiebolag filed Critical Sunds Defibrator Industries Aktiebolag
Publication of WO1990012919A1 publication Critical patent/WO1990012919A1/en

Links

Classifications

    • 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
    • D21F1/66—Pulp catching, de-watering, or recovering; Re-use of pulp-water
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/06—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums
    • B01D33/11—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums arranged for outward flow filtration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/44—Regenerating the filter material in the filter
    • B01D33/46—Regenerating the filter material in the filter by scrapers, brushes nozzles or the like acting on the cake-side of the filtering element
    • B01D33/466—Regenerating the filter material in the filter by scrapers, brushes nozzles or the like acting on the cake-side of the filtering element scrapers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/44—Regenerating the filter material in the filter
    • B01D33/48—Regenerating the filter material in the filter by flushing, e.g. counter-current air-bumps
    • B01D33/50—Regenerating the filter material in the filter by flushing, e.g. counter-current air-bumps with backwash arms, shoes or nozzles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/70—Filters with filtering elements which move during the filtering operation having feed or discharge devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D37/00—Processes of filtration
    • B01D37/02—Precoating the filter medium; Addition of filter aids to the liquid being filtered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B9/00—Presses specially adapted for particular purposes
    • B30B9/02—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material
    • B30B9/12—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material using pressing worms or screws co-operating with a permeable casing
    • 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
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/18—De-watering; Elimination of cooking or pulp-treating liquors from the pulp
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2201/00—Details relating to filtering apparatus
    • B01D2201/28—Position of the filtering element
    • B01D2201/287—Filtering elements with a vertical or inclined rotation or symmetry axis

Definitions

  • This invention relates to a device for dewatering pulp suspensions of various types, preferably cellulose pulp.
  • the fibre material is repeatedly diluted and dewatered, depending on its processing in different steps.
  • the dewatering can be carried out in different ways by using different types of equipment, for example suction filter, screw type presses, roll presses, disc presses and centrifuges.
  • suction filter for example suction filter, screw type presses, roll presses, disc presses and centrifuges.
  • the dewatering is desired to be carried out so that the liquid content in the pulp suspension is removed without the fibre material following along therewith.
  • the apertures in the screen surface, through which the dewatering takes place must not be made too small, in order to prevent the risk of clogging and as a result thereof the capacity of becoming too low.
  • the present invention which consists of a dewatering device of eentrifuge type, implies, that the aforesaid problems can be reduced.
  • the characterizing features of the invention become apparent from the attached claims.
  • the device shown comprises a screening cylinder 1, which is rotatable about a vertical rotation axis.
  • the screening cylinder is driven by a first motor 2 with variable speed.
  • a rotatable shaft 3 is located, whibh is driven separately by a second motor 4 with variable speed.
  • the shaft 3 is hollow and provided with an inlet 5 for the pulp suspension at its upper end and with supply openings 6 at the lower end of the screening cylinder 1.
  • the shaft 3 further is provided with a screw thread 7 for conveying the pulp upward through the screening cylinder 1 and simultaneously dewatering the pulp. The dewatering is obtained as a result of the effect of the centrifugal force. Due to the fact that the screening cylinder 1 and the shaft 3 are rotated in the same direction, but at a slightly different speed, the desired upward conveyance can be obtained. By adjusting this difference in speed, the pulp conveyance can be controlled.
  • the inlet 5 for the pulp suspension also can be located at the other end of the shaft 3. Alternatively, the inlet can be located directly in the bottom of the space inside of the screening cylinder 1. The essential feature is that the pulp suspension is supplied at the lower part of the screening cylinder 1.
  • the screw thread 7 does not extend all the way to the screening cylinder 1, thereby leaving a gap 8 between the saire.
  • the size of the gap should be 1-20 mm, preferably 3-10 mm.
  • outlets 9 for the dewatered pulp are located in the upper part of the screening cylinder 1. Outside of these outlet openings 9 a collecting device 10 is located to receive the dewatered pulp fed out through said openings 9.
  • the liquid separated by the screening cylinder 1 is collected in an outer chamber 11 enclosing the screening cylinder 1.
  • the liquid is discharged therefrom through an outlet 12.
  • a cleaning device 13 is located, which is axially movable along the screening cylinder 1 and formed with nozzles for spraying liquid or air inward to the screening dylinder 1.
  • the pulp suspension supplied through the shaft 3 preferably has a concentration of 1-4 %.
  • the pulp is rotated by the screw thread 7 and screening cylinder 1, so that the dewatering is brought about by the effect of the centrifugal force, In the gap 8 between the screw thread and screening cylinder a pulp layer is deposited.
  • This layer will serve as a filter medium, through which the dewatering takes place. Due to the pulp layer, the separation of the fibre material is very effective.
  • the thickness of the layer is determined by the screw thread.
  • the layer deposited possibly can be removed temporarily in a suitable manner, for example by an arrangement for rinsing as shown in the Figure.
  • the concentration of the pulp after the dewatering can amount to 30% or higher at the same time as the fibre content in the liquid is negligible.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Centrifugal Separators (AREA)
  • Paper (AREA)

Abstract

A dewatering device for pulp suspensions, comprising a rotatable screening cylinder (1). In the screening cylinder a rotatable shaft (3) is located which is provided with a screw thread (7) for conveying the pulp through the screening cylinder (1) while dewatering the same due to the effect of the centrifugal force. Between the screw thread (7) and screening cylinder (1) a gap (8) is formed, in which a layer of pulp can be deposited on the inside of the screening cylinder (1) in order thereby to act as a filter medium, through which the dewatering takes place.

Description

Dewatering device
This invention relates to a device for dewatering pulp suspensions of various types, preferably cellulose pulp.
At the making of papermaking pulp, the fibre material is repeatedly diluted and dewatered, depending on its processing in different steps. The dewatering can be carried out in different ways by using different types of equipment, for example suction filter, screw type presses, roll presses, disc presses and centrifuges. For acliieving a dry solids content of up to about 30% or higher, great forces are required, which render the equipment bulky and expensive and consume much energy.
The dewatering, of course, is desired to be carried out so that the liquid content in the pulp suspension is removed without the fibre material following along therewith. The apertures in the screen surface, through which the dewatering takes place, however, must not be made too small, in order to prevent the risk of clogging and as a result thereof the capacity of becoming too low. By increasing the dimensions of the screen apertures, however, the proportion of fibres following along with the liquid through the screen surface increases.
The present invention, which consists of a dewatering device of eentrifuge type, implies, that the aforesaid problems can be reduced. The characterizing features of the invention become apparent from the attached claims.
The invention is described in greater detail in the following, with reference to the accompanying Figure showing an embodiment of the invention.
The device shown comprises a screening cylinder 1, which is rotatable about a vertical rotation axis. The screening cylinder is driven by a first motor 2 with variable speed. In the screening cylinder 1 a rotatable shaft 3 is located, whibh is driven separately by a second motor 4 with variable speed. The shaft 3 is hollow and provided with an inlet 5 for the pulp suspension at its upper end and with supply openings 6 at the lower end of the screening cylinder 1. The shaft 3 further is provided with a screw thread 7 for conveying the pulp upward through the screening cylinder 1 and simultaneously dewatering the pulp. The dewatering is obtained as a result of the effect of the centrifugal force. Due to the fact that the screening cylinder 1 and the shaft 3 are rotated in the same direction, but at a slightly different speed, the desired upward conveyance can be obtained. By adjusting this difference in speed, the pulp conveyance can be controlled.
Although a device comprising a vertical or substantially vertical rotation shaft is preferred, an inclined or horizontal shaft can be imagined within the scope of the invention. The inlet 5 for the pulp suspension, of course, also can be located at the other end of the shaft 3. Alternatively, the inlet can be located directly in the bottom of the space inside of the screening cylinder 1. The essential feature is that the pulp suspension is supplied at the lower part of the screening cylinder 1.
The screw thread 7 does not extend all the way to the screening cylinder 1, thereby leaving a gap 8 between the saire. The size of the gap should be 1-20 mm, preferably 3-10 mm. In the upper part of the screening cylinder 1, outlets 9 for the dewatered pulp are located. Outside of these outlet openings 9 a collecting device 10 is located to receive the dewatered pulp fed out through said openings 9. The liquid separated by the screening cylinder 1 is collected in an outer chamber 11 enclosing the screening cylinder 1. The liquid is discharged therefrom through an outlet 12. On the outside of the screening cylinder 1 and concentrically therewith, a cleaning device 13 is located, which is axially movable along the screening cylinder 1 and formed with nozzles for spraying liquid or air inward to the screening dylinder 1.
The pulp suspension supplied through the shaft 3 preferably has a concentration of 1-4 %. Upon its flowing out through the supply openings 6 the pulp is rotated by the screw thread 7 and screening cylinder 1, so that the dewatering is brought about by the effect of the centrifugal force, In the gap 8 between the screw thread and screening cylinder a pulp layer is deposited. This layer will serve as a filter medium, through which the dewatering takes place. Due to the pulp layer, the separation of the fibre material is very effective. The thickness of the layer is determined by the screw thread. The layer deposited possibly can be removed temporarily in a suitable manner, for example by an arrangement for rinsing as shown in the Figure. From the annular rinsing means 13 liquid is sprayed to the screening cylinder 1, so that the deposited layer is solved. By moving the rinsing means 13 upward along the screening cylinder 1, the entire layer is removed while a new layer is deposited at the same time. This can be of interest when the pulp layer is too heavily clogged by fine material so that the capacity is decreased.
The concentration of the pulp after the dewatering can amount to 30% or higher at the same time as the fibre content in the liquid is negligible.
The invention, of course, is not restricted to the enlbodiment shown, but can be varied within the scope of the invention idea.

Claims

Claims
1. A device for dewatering pulp suspensions, comprising an inlet (5) for the pulp to the interior of a rotatable screening cylinder provided with screen apertures, a rotatable shaft (3) located in the screening cylinder with a screw thread (7) intended to convey the pulp suspension along the screening cylinder (1) while dewatering due to the effect of the centrifugal force, and outlets (12 and 9, respectively) for liquid and dewatered pulp, respectively, characterized in that the screw thread
(7) and screening cylinder (1) between themselves form a gap (8), in which a layer of pulp can be deposited on the inside of the screenϋg cylinder (1) in order thereby to act as a filter medium, through which the dewatering takes place.
2. A dayice as defined in claim 1, c h a r a c t e r i z e d in that the gap (8) between the screw thread (7) and screening cylinder amounts to 1-20 mm, preferably 3-10 mm.
3. A device as defined in claim 1 or 2, characterized in that the screening cylinder (1) has vertical rotation axis, and that the pulp inlet (5) is located through the shaft (3), which is provided with supply openings (6) at the lower portion of the screening cylinder (1), and the screw thread (7) is arranged to convey the pulp upward through the screening cylinder (1).
4. A device as defined in claim 1,2 or 3, charact erized in that it comprises an arrangement for temporarily removing the pulp layer deposited in the gap(8), when required.
5. A device as defined in claim 4, c h a r a c t e r i z e d in that an axially movable cleaning means (13) is located about the outer surface of the screening cylinder (1), for spraying liquid or air inward to the screening cylinder in order thereby to remove the deposited pulp layer.
PCT/SE1990/000168 1989-04-17 1990-03-15 Dewatering device WO1990012919A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8901373A SE463425B (en) 1989-04-17 1989-04-17 dewatering
SE8901373-4 1989-04-17

Publications (1)

Publication Number Publication Date
WO1990012919A1 true WO1990012919A1 (en) 1990-11-01

Family

ID=20375690

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1990/000168 WO1990012919A1 (en) 1989-04-17 1990-03-15 Dewatering device

Country Status (3)

Country Link
AU (1) AU5541790A (en)
SE (1) SE463425B (en)
WO (1) WO1990012919A1 (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993011851A2 (en) * 1991-12-05 1993-06-24 Maximilian Kriegl Particulate material separator
EP0549092A1 (en) * 1991-12-20 1993-06-30 Fukoku Kogyo Co. Ltd. Rotary drum filter
WO1995011076A1 (en) * 1993-10-21 1995-04-27 Joseph Gardner Slurry separator
GB2297281A (en) * 1993-10-21 1996-07-31 Joseph Gardner Slurry separator
EP0933470A2 (en) * 1998-02-03 1999-08-04 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Dewatering concentrator
US6071378A (en) * 1995-07-17 2000-06-06 Kvaerner Pulping Ab Method and device for treating a pulp suspension
US6139685A (en) * 1998-01-16 2000-10-31 Kvaerner Pulping Ab Method and device for treating a pulp suspension
EP2202052A1 (en) * 2008-12-29 2010-06-30 Andritz AG Method and device for dehydrating and dispersing a fibrous material
WO2014037187A1 (en) * 2012-09-06 2014-03-13 Siemens Vai Metals Technologies Gmbh Slurry dewatering device
EP2764156A4 (en) * 2011-10-03 2015-05-27 Valmet Aktiebolag Pulp distribution device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107640881A (en) * 2017-11-03 2018-01-30 张佩春 A kind of sewage pre-dehydration device of band recoil cleaning

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2019237A (en) * 1978-03-29 1979-10-31 Uop Inc Process for dewatering fibrous waste
SE421434B (en) * 1978-06-14 1981-12-21 Berggren Torsten L SCREW PRESS

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2019237A (en) * 1978-03-29 1979-10-31 Uop Inc Process for dewatering fibrous waste
SE421434B (en) * 1978-06-14 1981-12-21 Berggren Torsten L SCREW PRESS

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993011851A3 (en) * 1991-12-05 1993-07-22 Maximilian Kriegl Particulate material separator
US5507947A (en) * 1991-12-05 1996-04-16 Kriegl; Maximilian Centrifugal apparatus for separating particulate material
WO1993011851A2 (en) * 1991-12-05 1993-06-24 Maximilian Kriegl Particulate material separator
EP0549092A1 (en) * 1991-12-20 1993-06-30 Fukoku Kogyo Co. Ltd. Rotary drum filter
AU654863B2 (en) * 1991-12-20 1994-11-24 Fukoku Kogyo Co., Ltd. Rotary filter
WO1995011076A1 (en) * 1993-10-21 1995-04-27 Joseph Gardner Slurry separator
GB2297281A (en) * 1993-10-21 1996-07-31 Joseph Gardner Slurry separator
GB2297281B (en) * 1993-10-21 1998-04-01 Joseph Gardner Slurry separator
US6071378A (en) * 1995-07-17 2000-06-06 Kvaerner Pulping Ab Method and device for treating a pulp suspension
US6139685A (en) * 1998-01-16 2000-10-31 Kvaerner Pulping Ab Method and device for treating a pulp suspension
EP0933470A2 (en) * 1998-02-03 1999-08-04 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Dewatering concentrator
EP0933470A3 (en) * 1998-02-03 2000-05-17 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Dewatering concentrator
US6261417B1 (en) 1998-02-03 2001-07-17 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Dehydrating concentrator
EP2202052A1 (en) * 2008-12-29 2010-06-30 Andritz AG Method and device for dehydrating and dispersing a fibrous material
EP2764156A4 (en) * 2011-10-03 2015-05-27 Valmet Aktiebolag Pulp distribution device
WO2014037187A1 (en) * 2012-09-06 2014-03-13 Siemens Vai Metals Technologies Gmbh Slurry dewatering device

Also Published As

Publication number Publication date
SE8901373D0 (en) 1989-04-17
SE463425B (en) 1990-11-19
AU5541790A (en) 1990-11-16
SE8901373L (en) 1990-10-18

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