EP0475669B1 - Massenturm und Vorrichtung zum dessen Ablassen - Google Patents

Massenturm und Vorrichtung zum dessen Ablassen Download PDF

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Publication number
EP0475669B1
EP0475669B1 EP91308097A EP91308097A EP0475669B1 EP 0475669 B1 EP0475669 B1 EP 0475669B1 EP 91308097 A EP91308097 A EP 91308097A EP 91308097 A EP91308097 A EP 91308097A EP 0475669 B1 EP0475669 B1 EP 0475669B1
Authority
EP
European Patent Office
Prior art keywords
pulp
tower
vessel
pump
suction duct
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
EP91308097A
Other languages
English (en)
French (fr)
Other versions
EP0475669A3 (en
EP0475669A2 (de
Inventor
Arto Koso
Voitto Reponen
Reijo Vesala
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.)
Ahlstrom Corp
Original Assignee
Ahlstrom Corp
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 Ahlstrom Corp filed Critical Ahlstrom Corp
Publication of EP0475669A2 publication Critical patent/EP0475669A2/de
Publication of EP0475669A3 publication Critical patent/EP0475669A3/en
Application granted granted Critical
Publication of EP0475669B1 publication Critical patent/EP0475669B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • D21C7/08—Discharge devices

Definitions

  • the present invention relates to a mass tower or other vessel as used in the pulp and paper industry and which is normally filled with medium or high consistency pulp, and means for the discharge thereof.
  • Pulp from a high or medium consistency mass tower has hitherto been discharged from the bottom part of the tower by a conventional centrifugal pump, which has required the dilution of pulp usually to a consistency of about 6% maximum.
  • a centrifugal medium consistency pump has gained ground in pumping medium consistency pulps, whereby it is natural that the discharge of the mass tower is carried out with said so called MC-pump.
  • the MC-pump may, of course, be positioned at the bottom of the tower and if required also, for example, equipment illustrated in EP-A-0269124 and EP-A-0323749 may be used to ensure the flow of the pulp to the pump.
  • the pump arranged in communication with the mass tower is in most cases attached to the conic wall portion of the mass tower.
  • the output of an MC-pump gradually reduces whereas the energy consumption increases.
  • the deduction is that the pump for some reason does not receive a sufficient amount of pulp anymore, and even the addition of dilution water offers only a temporary solution for the problem.
  • Apparatus for pumping low consistency pulps are also known, for instance, from Ahlstroms Massabok, 1981, Söderströms Konsultbyr ⁇ AB, Norrköping, Sweden, pages 3, 32, 33, where pulp is discharged from the bottom of a pulp containing vessel by means of a single ordinary (non-fluidizing) centrifugal pump having a suction duct extending inside the pulp vessel.
  • a single ordinary centrifugal pump having a suction duct extending inside the pulp vessel.
  • the described structure cannot be used to handle medium consistency pulps and it is not taught to be used in removing pulp from a moving layer of pulp.
  • the arrangement according to the present invention has in the performed tests eliminated or minimized the above described problem.
  • an apparatus comprising a mass tower or other pulp vessel and means for the discharge of high or medium consistency pulp when contained therein, in which a bottom portion of said pulp vessel is provided with a first pump for removing pulp from the tower and a second and separate pump communicates with the inside of the vessel via a suction duct having an inlet orifice, characterised in that the inside wall of the vessel is provided with means permitting continuous pumping of pulp by the second pump, said means comprising either an extension of the duct into the interior of the vessel, or a member arranged adjacent to the suction duct for feeding pulp against the suction duct or against the inner wall of the vessel.
  • a method of discharging high or medium consistency pulp from a mass tower or other pulp vessel wherein pulp is continuously removed from the bottom part of the vessel by means of a first pump and also pumping pulp by means of a separate second pump, characterised in that pulp is continuously removed from the vessel also by means of the second pump by either causing a continuous flow of pulp past the inlet orifice of an extraction duct located upstream of the first pump and spaced from the inside wall surface of said vessel so as to be in the region wherein pulp continuously flows, or by feeding pulp against the suction duct or against the inner wall of the vessel.
  • FIG. 1 illustrates a modern discharge arrangement of a high consistency mass tower in accordance with the prior art.
  • a high consistency mass tower 10 consists in the embodiment according to the drawing of three portions: a cylindrical upper portion 12, a conical intermediate portion 14 and a cylindrical bottom portion 16.
  • a conventional centrifugal pump 20 designed for low consistency pulps is attached to the wall of the cylindrical bottom portion 16 of the tower.
  • a feed conduit (not shown) for a dilution liquid and a mixer 22 for mixing the liquid into the pulp to improve the pumpability thereof are arranged in front of the pump 20.
  • the wall in the conical intermediate portion 14 of the tower 10 is provided with an MC-pump 24, by which pulp is pumped without dilution at its original consistency.
  • the MC-pump can also be attached to the cylindrical upper portion 12 of the tower, as illustrated by the alternative upper MC-pump 26 in the drawing.
  • Fig. 2 illustrates a theory of why the pumping of high consistency pulp is not successful of a period of time, at least from the conical portion of the tower.
  • the broken lines A and B in the drawing show the variations of the levels of the pulp surface on discharging and on filling respectively. It may be noted that always when the height of the surface of the pulp decreases, the pulp surface A in the center part of the tower drops, because the friction alone between the pulp and the walls of the tower causes such effect. On the other hand, the conical portion of the tower in a way also forces the pulp to move towards the center of the tower, which contributes to the deceleration of the downwards movement of the pulp. Further it is known that the pulp thickens adjacent to the tower wall.
  • FIG. 3 illustrates a solution to the above-mentioned problem.
  • a vertical suction duct 32 is mounted extending through a wall 30 of the downwards, preferably conically, reducing portion 14 of the mass tower 10, the duct 32 extending sufficiently far into the interior of vessel 10 to permit continuous pumping, in other words it extends all the way through even a thick dewatered pulp layer to the zone of moving pulp, and the suction opening of which duct is preferably also open against the flow direction of the pulp, whereby in either case there is no need to doubt the flow of pulp down to the bottom of said suction duct 32, which bottom is provided with a separate pump 34, preferably a so called MC-pump.
  • the realization of the arrangement in accordance with the invention is characterized in that the bottom portion of the tower is provided with a first pump (not shown), by which pulp is pumped substantially continuously from the vessel 10, which causes the continuous flow of pulp past the duct orifice, in other words the so called suction opening, of the suction duct 32 arranged in the conical portion 14.
  • the extension of the suction duct 32 to the inside of the vessel in other words the distance of the suction duct from the inner surface of the vessel, must be according to the performed experiments at least about 50% of the diameter of the suction duct.
  • a greater diameter does not disturb, but if the diameter diminishes, problems may be encountered by some easily filtering pulp types.
  • Fig. 4 illustrates an additional possibility of arranging a suction duct 36 at right angles against the conical wall 30.
  • An additional advantage for both arrangements is that the fluidizing MC-pump 34 or possibly the means disclosed in Fig. 7 of EP-A-0 323 749 can be arranged on a conventional basis in the bottom, and not be hung on the wall of the mass tower, as is characteristic of the previous technique.
  • Figs. 3 and 4 additionally illustrate an apparatus to be preferably added to communicate with suction duct 32, 36, namely a collar or baffle plate 42, the purpose of which is to cover a pocket otherwise formed between the suction duct and the tower wall, to which pocket the downward flowing pulp is liable to accumulate.
  • the collar plate 42 is preferably formed to pass or deflect as well as possible the pulp to the sides of the suction duct so that the generation of a pulp layer on the collar plate itself is substantially prevented.
  • Fig. 5 illustrates an open screw 40 arranged in front of the opening of an upright suction duct 38 to prevent the generation of a thickened pulp layer in front of the suction duct 38 and to transfer pulp towards the orifice of the suction duct 38.
  • Fig. 6 illustrates a similar arrangement to Fig. 5 applied in front of the orifice of a discharge duct for pulp located perpendicular to in the conical portion.
  • the purpose of the screw 40 is, as mentioned, to feed pulp towards the wall of tower/mass tower 10 and thus prevent the generation of a pulp layer otherwise tending to accumulate on the wall.
  • the screw does not actually operate as a feeding apparatus for the suction duct, but as was stated above, it prevents the thickening of the pulp on the surface of the mass tower by feeding the pulp against the wall of the vessel.
  • a rotating scraper may also or alternatively be used for a similar purpose, which scraper mechanically loosens the pulp layer accumulated on the wall.
  • the suction duct in accordance with the present invention be arranged either is a perpendicular or inclined position relative to the cylindrical portion of the mass tower, or that the screw shown in the drawings is positioned to some other position other that a completely horizontal position or that the vessel is completely cylindrical or of some other form appropriate for the purpose, or that the suction duct of the vessel has been extended deep into the vessel, for example through the bottom of the vessel, to mention some of the possible variations of the invention.

Landscapes

  • Paper (AREA)
  • Buildings Adapted To Withstand Abnormal External Influences (AREA)
  • Harvester Elements (AREA)
  • Vibration Prevention Devices (AREA)
  • Medicines Containing Material From Animals Or Micro-Organisms (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

Claims (11)

  1. Stoffbehälter (10) oder anderer Pulpebehälter (10) und Mittel für den Ablaß von hoch- oder mittelkonsistenter Pulpe, wenn welche darin vorhanden ist, wobei ein unterer Teil des Pulpebehälters mit einer ersten Pumpe für den Ablaß von Pulpe aus dem Behälter (10) versehen ist und eine zweite und getrennte Pumpe (34) über einen Saugkanal (32, 36, 38) mit Eintrittsöffnung mit der Innenseite des Behälters (10) in Verbindung steht, dadurch gekennzeichnet, daß die Innenwand (30) des Behälters (10) mit Mitteln (32, 36, 40) versehen ist, die das kontinuierliche Pumpen der Pulpe mit der zweiten Pumpe (34) ermöglichen, welche Mittel entweder aus einer Verlängerung des Kanals (32, 36) in das Innere des Behälters (10) oder einem nah am Saugkanal (38) angeordneten Organ (40) bestehen zur Beförderung von Pulpe gegen den Saugkanal (38) oder gegen die Innenwand (30) des Behälters (10).
  2. Vorrichtung gemäß Anspruch 1, dadurch gekennzeichnet, daß der Abstand der Saugöffnung des Saugkanals (32, 36) zur Innenfläche des Behälters (10) zumindest dem 0,5fachen Durchmesser der Saugöffnung entspricht.
  3. Vorrichtung gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, daß der Stoffbehälter (10) zusätzlich zum Unterteil (16) einen hauptsächlich zylindrischen Oberteil (12) und einen konischen Mittelteil (14) umfaßt.
  4. Vorrichtung gemäß Anspruch 3, dadurch gekennzeichnet, daß der Saugkanal (32, 36) im konischen Mittelteil (14) angeordnet ist.
  5. Vorrichtung gemäß Anspruch 4, dadurch gekennzeichnet, daß der Saugkanal (32) in geneigter Lage gegenüber der Wand des Behälters (10) verläuft.
  6. Vorrichtung gemäß Anspruch 4, dadurch gekennzeichnet, daß sich der Saugkanal (36) in einer senkrechten Lage gegenüber der Wand des Behälters (10) befindet oder in rechtem Winkel zur Wand verläuft.
  7. Vorrichtung gemäß zumindest Anspruch 1, dadurch gekennzeichnet, daß das Organ (40) eine Schraube ist.
  8. Vorrichtung gemäß zumindest Anspruch 1, dadurch gekennzeichnet, daß, das Organ (40) ein umlaufender Schaber oder desgleichen ist.
  9. Vorrichtung gemäß zumindest Anspruch 1, dadurch gekennzeichnet, daß sich der Saugkanal durch die Seitenwand des Behälters hindurch in das Innere des Behälters (10) erstreckt.
  10. Vorrichtung gemäß zumindest Anspruch 1, dadurch gekennzeichnet, daß sich der Saugkanal durch den Boden des Behälters (10) hindurch zur Innenseite des Behälters (10) erstreckt.
  11. Verfahren zum Ablassen von hoch- oder mittelkonsistenter Pulpe aus einem Stoffbehälter oder anderem Pulpebehälter (10), wo Pulpe aus dem unteren Teil des Behälters (10) mit einer ersten Pumpe kontinuierlich abgelassen wird und Pulpe auch mit einer getrennten zweiten Pumpe (34) gepumpt wird, dadurch gekennzeichnet, daß Pulpe aus dem Behälter (10) auch mit der zweiten Pumpe (34) kontinuierlich abgelassen wird, entweder indem ein kontinuierlicher Pulpefluß an der Eintrittsöffnung eines Saugkanals vorbei geleitet wird, der stromaufwärts von der ersten Pumpe angeordnet und zur Innenwand (30) des Behälters (10) beabstandet ist, um sich in derjenigen Region zu befinden, wo Pulpe kontinuierlich fließt, oder indem Pulpe gegen den Saugkanal (38) oder gegen die Innenwand (30) des Behälters (10) gefördert wird.
EP91308097A 1990-09-05 1991-09-04 Massenturm und Vorrichtung zum dessen Ablassen Expired - Lifetime EP0475669B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI904374A FI85392C (fi) 1990-09-05 1990-09-05 Anordning foer urlastning av massabehaollare.
FI904374 1990-09-05

Publications (3)

Publication Number Publication Date
EP0475669A2 EP0475669A2 (de) 1992-03-18
EP0475669A3 EP0475669A3 (en) 1993-01-20
EP0475669B1 true EP0475669B1 (de) 1995-11-29

Family

ID=8531020

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91308097A Expired - Lifetime EP0475669B1 (de) 1990-09-05 1991-09-04 Massenturm und Vorrichtung zum dessen Ablassen

Country Status (5)

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EP (1) EP0475669B1 (de)
AT (1) ATE130887T1 (de)
DE (1) DE69114965T2 (de)
ES (1) ES2082147T3 (de)
FI (1) FI85392C (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0965682A1 (de) 1998-06-17 1999-12-22 Voith Sulzer Papiertechnik Patent GmbH Verfahren und Behälter zum Stapeln von hochkonsistentem Papierfaserstoff
DE10156201C1 (de) * 2001-11-15 2002-10-17 Voith Paper Patent Gmbh Verfahren und Behälter zum Stapeln von hochkonsistentem Papierfaserstoff
CN101809227B (zh) * 2007-09-17 2012-06-20 苏舍泵有限公司 用于从容器排出纸浆的装置、从容器排出纸浆的方法以及改进纸浆容器的方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB150782A (en) * 1919-06-04 1920-09-06 Samuel Milne Improvements in and relating to stationary digesters and the like used in paper making and the like
FI79361B (fi) * 1988-01-05 1989-08-31 Ahlstroem Oy Foerfarande och apparatur foer underlaettande av uttoemning av fallroer eller liknande och behandling av massa i sagda utrymme.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Ahlströms Massabok, 1981, Söderströms Konsultbyra AB, Norrköping, Sweden, pages 3, 32, 33. *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0965682A1 (de) 1998-06-17 1999-12-22 Voith Sulzer Papiertechnik Patent GmbH Verfahren und Behälter zum Stapeln von hochkonsistentem Papierfaserstoff
DE19826879A1 (de) * 1998-06-17 1999-12-30 Voith Sulzer Papiertech Patent Verfahren und Behälter zum Stapeln von hochkonsistentem Papierfaserstoff
DE19826879B4 (de) * 1998-06-17 2005-06-02 Voith Paper Patent Gmbh Verfahren und Behälter zum Stapeln von hochkonsistentem Papierfaserstoff
DE10156201C1 (de) * 2001-11-15 2002-10-17 Voith Paper Patent Gmbh Verfahren und Behälter zum Stapeln von hochkonsistentem Papierfaserstoff
EP1312712A2 (de) * 2001-11-15 2003-05-21 Voith Paper Patent GmbH Verfahren und Behälter zum Stapeln von hochkonsistentem Papierfaserstoff
EP1312712A3 (de) * 2001-11-15 2004-01-02 Voith Paper Patent GmbH Verfahren und Behälter zum Stapeln von hochkonsistentem Papierfaserstoff
CN101809227B (zh) * 2007-09-17 2012-06-20 苏舍泵有限公司 用于从容器排出纸浆的装置、从容器排出纸浆的方法以及改进纸浆容器的方法

Also Published As

Publication number Publication date
FI904374A (fi) 1991-12-31
FI85392B (fi) 1991-12-31
EP0475669A3 (en) 1993-01-20
DE69114965D1 (de) 1996-01-11
DE69114965T2 (de) 1996-04-18
ES2082147T3 (es) 1996-03-16
FI904374A0 (fi) 1990-09-05
EP0475669A2 (de) 1992-03-18
FI85392C (fi) 1992-04-10
ATE130887T1 (de) 1995-12-15

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