NO135261B

NO135261B -

Info

Publication number: NO135261B
Application number: NO3717/69A
Authority: NO
Inventors: B E Pettersson
Original assignee: Sunds Ab
Priority date: 1968-09-18
Filing date: 1969-09-17
Publication date: 1976-11-29
Also published as: FI54348B; JPS4930001B1; FI54348C; SE402136B; NO135261C

Description

på en fremgangsmåte og en anordning for fraskilning av væske fra fibersuspensjoner av cellulosemasse, hvorunder fraskilningen ut-føres i en fortrinnsvis stående beholder med kontinuerlig aksiell gjennommatning av fibersuspensjonen og hvor væske bringes til å passere gjennom fibersuspensjonen i vinkel med dennes bevegelsesretning i beholderen, og i retning mot flere over beholderens tverrsnitt fordelte og stasjonært i fibersuspensjonen anordnede, med gjennombrutte, hensiktsmessig perforerte vegger forsynte rom for oppsamling av væske som fraskilles fra fibersuspensjonen mens fibrene helt eller tilnærmet helt blir tilbake på utsidene av oppsamlingsrommene. Ifølge patentet avbrytes innstrømningen av den fortrengte eller utskilte væske i oppsamlingsrommene helt eller delvis under et i det vesentligste kontinuerlig oppsamlings-forløp med hensiktsmessige, periodisk tilbakekommende intervaller ved hjelp av trykkpulser som forplanter seg fra innsiden av opp-saml ingsrommene og til silåpningene, hvorved fibersuspensjonens bevegelse langs og forbi utsiden av oppsamlingsrommenes gjennombrutte vegger lettes, og samtidig inntrykni-ng av fibre gjennom de gjennombrutte vegger forebygges. on a method and a device for separating liquid from fiber suspensions of cellulose pulp, during which the separation is carried out in a preferably standing container with continuous axial feed through of the fiber suspension and where liquid is caused to pass through the fiber suspension at an angle with its direction of movement in the container, and in direction towards several spaces distributed over the cross-section of the container and arranged stationary in the fiber suspension, with broken through, appropriately perforated walls provided with spaces for collecting liquid that is separated from the fiber suspension while the fibers completely or almost completely remain on the outside of the collection spaces. According to the patent, the inflow of the displaced or secreted liquid into the collection chambers is interrupted in whole or in part during an essentially continuous collection course at appropriate, periodically recurring intervals by means of pressure pulses that propagate from the inside of the collection chambers and to the sieve openings, whereby the fiber suspension movement along and past the outside of the collection rooms' perforated walls is facilitated, and at the same time the penetration of fibers through the perforated walls is prevented.

Ifølge patentet kan trykkpulsene tilveiebringes under formidling av væske i minst én med oppsamlingsrommene kommunise-rende ledning. According to the patent, the pressure pulses can be provided while conveying liquid in at least one line communicating with the collection spaces.

Det har nå vist seg a-t det ifølge en fordelaktig videre utvikling av den forannevnte fremgangsmåte er mulig som medium til formidling av trykkvariasjonene å anvende gass, f.eks. luft. En betydelig fordel ved anvendelse av f.eks. luft som medium for formidling av trykkpulsene Tsestår i at akselerasjons-kreftene på pulsmediet blir av en helt annen størrelsesorden enn ved anvendelse av f.eks. vann, da luftens volumvekt ved 1 atm. og 0°C bare utgjør ca. 1/800 av vannets volumvekt. Videre oppnås, på grunn av pulsmediets (gassens, luftens) mindre tetthet og/eller den lengre pulstid (tidsfaktoren er ikke kritisk ved pulseringen) som kan anvendes, en jevnere trykkfordeling. Slutlig kan det oppnås en høyere tilbakestrømningshastighet samt en høyere effektiv dreneringshastighet av vaskevæsken. It has now been shown that, according to an advantageous further development of the aforementioned method, it is possible to use gas as a medium for communicating the pressure variations, e.g. air. A significant advantage when using e.g. air as a medium for conveying the pressure pulses This is because the acceleration forces on the pulse medium are of a completely different order of magnitude than when using e.g. water, as the volumetric weight of air at 1 atm. and 0°C only amounts to approx. 1/800 of the water's volume weight. Furthermore, due to the lower density of the pulse medium (gas, air) and/or the longer pulse time (the time factor is not critical during the pulsation) that can be used, a more uniform pressure distribution is achieved. Finally, a higher return flow rate can be achieved as well as a higher effective drainage rate of the washing liquid.

Oppfinnelsen skal i det følgende klargjøres nærmere The invention will be clarified in more detail below

under henvisning til tegningen, hvor f ig. 1 viser et vertikal snitt gjennom en del av en for utførelse av oppfinnelsen i praksis fordelaktig anordning, tilsluttet'til en stående beholder for behand-ling av fiberholdig materiale, mens fig. 2 i vertikalsnitt og i større målestokk illustrerer anordningen samt hvorledes ledningen fra gass- (luft:-) pulsatoren er forbundet med anordningen. Fig. 3 <! >viser likeledes i vertikalsnitt og i større målestokk en modifi-sert utførelse av anordningen for tilførsel av gass til utsiden av et oppsamlingsrom for avskilt væske. with reference to the drawing, where fig. 1 shows a vertical section through part of an advantageous device for carrying out the invention in practice, connected to a standing container for treating fibrous material, while fig. 2 in vertical section and on a larger scale illustrates the device and how the line from the gas (air:-) pulsator is connected to the device. Fig. 3 <! >also shows in vertical section and on a larger scale a modified version of the device for supplying gas to the outside of a collection room for separated liquid.

på tegningen betegner 1 en del. av det øvre parti av en stående, hensiktsmessig sylindrisk beholder, innrettet til å gjennomstrømmes kontinuerlig i den med pilene A antydede retning av behandlingsgods, fortrinnsvis cellulosemasse 2. Det totale rom for-behandlings-(vaske-) væskens innføring er betegnet med 3, in the drawing, 1 denotes a part. of the upper part of an upright, suitably cylindrical container, designed to continuously flow through in the direction indicated by the arrows A of processing material, preferably cellulose pulp 2. The total space for the introduction of the processing (washing) liquid is denoted by 3,

og 4 er en på en roterbar aksel 5 fast anbragt tårnskraper av kjent utførelse. 6, 7 og 8 er tilførselsrom for vaskevæske, h-vilke rom kan være stasjonært og/eller roterbart anordnet. Likeledes kan de være av forut kjent utførelse, f.eks. utført som tilnærmet vertikalt rettede sprøyterør eller munnstykker som beveges i baner som er konsentriske med ringformede oppsamlingsrør for frasilt væske, som vist i svensk patentskrift 198 496. 9 og .10 betegner oppsamlingsrom for avsilt væske, hvilke rom hensiktsmes-sig er utført som ringformede silkurver, som vist på fig. 3. Opp-saml ing sr omme ne 9 og 10 kommuniserer med ett eller flere rør 11 for bortføring av den avsilte væske via et overløp 12. Oppsamlingsrommene 9 og 10 kommuniserer videre med minst ett rør 13 som er tilsluttet til en anordning for frembringelse av trykkpulser ved hjelp av gass, fortrinnsvis luft. Vedkommende anordning om-fatter en beholder 14 bestemt til å mates med gass (luft). I rø-ret 13 er innkoblet en av f.eks. et tidsrelé styrt magnetventil 15. Tidsreléet setter oppsamlingsrommene avvekslende i forbindelse med trykkbeholderen 14 og atmosfæren. De frembragte trykkpulser tilveiebringer en gass-(luft-) og/eller væskestrømning gjennom slis- and 4 is a tower scraper of known design fixedly placed on a rotatable shaft 5. 6, 7 and 8 are supply spaces for washing liquid, which spaces can be stationary and/or rotatably arranged. Likewise, they can be of previously known design, e.g. performed as approximately vertically directed spray tubes or nozzles that move in paths that are concentric with annular collection tubes for strained liquid, as shown in Swedish patent document 198 496. 9 and .10 denote collection spaces for strained liquid, which spaces are suitably designed as ring-shaped sieve baskets , as shown in fig. 3. Collection rooms 9 and 10 communicate with one or more pipes 11 for carrying away the filtered liquid via an overflow 12. The collection rooms 9 and 10 further communicate with at least one pipe 13 which is connected to a device for producing pressure pulses using gas, preferably air. The relevant device includes a container 14 intended to be fed with gas (air). In the tube 13, one of e.g. a time relay controlled solenoid valve 15. The time relay alternately connects the collection spaces to the pressure vessel 14 and the atmosphere. The produced pressure pulses provide a gas (air) and/or liquid flow through slits

Claims

sinew or the holes 16 in the walls of the collection chambers 9 and 10, which prevents clogging of the holes 16 and thus facilitates the flow of the worn-out liquid (indicated by arrows B). The limits for the liquid level in the strainer are on fig. 2 marked with a double pii c. A line 19 leads washing liquid to the compartment 3, 8, while the line 22 serves to supply washing liquid to the annular rooms 6 and 7. Washing liquid flows from the rooms 8, 6 and 7 in the transverse direction through the suspension column in the direction towards the rooms 9 and 10, in which rooms the separated liquid is collected and carried away through the pipes 11. Finished material (washed pulp) passes out through the outlet 20. 1. Method for separating liquid from fiber suspensions of cellulose pulp, during which the separation is carried out in a preferably standing container with continuous axial feed through of the fiber suspension and through which liquid is made to pass. through the fiber suspension at an angle with its direction of movement in the container, and in the direction of several spaces (9, 10) distributed over the container's cross-section and arranged stationary in the fiber suspension, provided with broken through, appropriately perforated walls, for collecting liquid that separates from the fiber suspension while the fibers completely or almost completely remains on the outside of the collection spaces, and where the inflow of the displaced or secreted liquid into the collection spaces is completely or partially interrupted at appropriate, periodically recurring intervals by means of pressure pulses that propagate from the inside of the collection spaces and to the sieve openings, whereby the movement of the fiber suspension along and past the outside of the collection rooms' perforated walls is facilitated and at the same time intrusion of fibers through the perforated walls is prevented, characterized in that the pressure pulses are provided during the mediation of a gas, suitable air, as a gas space is maintained over a v box level in the collection rooms and where rapid pressure pulses are provided in the collection

the chambers, as the gas pressure rises and falls alternately in the gas chamber.

2. Device for carrying out the method specified in claim 1 by separating liquid from fiber suspensions of cellulose pulp, comprising a preferably standing container arranged for continuous axial feed through of a fiber suspension intended for liquid separation, suitably with a high concentration, where several in the container, stationary arranged with pierced, appropriately perforated walls, provided with collection spaces (9, 10) for liquid that is separated from the fiber suspension, which collection spaces are distributed over the container's cross-section and located below the assumed fiber suspension level, and to which collection spaces at least one line is connected for carrying away the separated liquid, characterized in that the upper gas-filled part of the collection space has unbroken walls, and that at least one line (13) for gas is connected to the collection space, which line is intended to transmit pressure pulses to the collection space from a device that provides pressure p bubbles in the gas, and that the collection space has an upper gas-filled part and a lower liquid-filled part.

3. Device as stated in any one of claims 3 to 5, characterized in that a time relay-controlled solenoid valve is arranged in the gas supply line (13) for controlling time intervals between the pressure surges. 4.... Device as specified in claims 2 and 3, characterized in that collection spaces (9,10) located at different diameters are connected to different drain lines (11).