EP0070782B1 - Method of making a cellulosic fibre pulp for non paperlike applications - Google Patents

Method of making a cellulosic fibre pulp for non paperlike applications Download PDF

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Publication number
EP0070782B1
EP0070782B1 EP82401346A EP82401346A EP0070782B1 EP 0070782 B1 EP0070782 B1 EP 0070782B1 EP 82401346 A EP82401346 A EP 82401346A EP 82401346 A EP82401346 A EP 82401346A EP 0070782 B1 EP0070782 B1 EP 0070782B1
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EP
European Patent Office
Prior art keywords
pitch
pulping
pulp
fibres
reverse
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EP82401346A
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German (de)
French (fr)
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EP0070782A1 (en
Inventor
Pierre Berger
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Clextral SAS
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Clextral SAS
Creusot Loire SA
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Priority to AT82401346T priority Critical patent/ATE15918T1/en
Publication of EP0070782A1 publication Critical patent/EP0070782A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/22—Extrusion presses; Dies therefor
    • B30B11/24—Extrusion presses; Dies therefor using screws or worms
    • B30B11/246—Screw constructions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/22—Extrusion presses; Dies therefor
    • B30B11/24—Extrusion presses; Dies therefor using screws or worms
    • B30B11/243—Extrusion presses; Dies therefor using screws or worms using two or more screws working in the same chamber
    • 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

Definitions

  • the subject of the invention is a method and an installation for manufacturing a pulp of cellulosic fibers which can be used especially in non-paper fields without any treatment other than drying.
  • the chips can be disaggregated purely mechanically by means of grinding wheels, for example.
  • the so-called mechanical pastes are then obtained.
  • the chips undergo cooking for a fairly long time in devices called digesters allowing the reagent to attack the ligin which dissolves in the liquid phase.
  • the so-called chemical pulps are obtained which are easily disintegrated, for example by blowing with compressed air.
  • the paste obtained at the end of the defibration treatment is in the form of a very dilute suspension which must be washed, bleached and then wrung out.
  • the Depositing Company has been developing for a few years a new process and a new machine for defibrating wood chips.
  • This machine described, in particular in French patent no. 2319737 comprises at least two identical threaded screws meshing in one another and rotated inside a sheath provided with an upstream inlet orifice for the chips and a downstream outlet for the defibrated material; the threads of the screws have varied pitches which determine a succession of treatment zones each comprising a direct pitch section in which the material is entrained downstream and an inverted pitch section which slows down the advancement of the material and consequently determines an increase in pressure.
  • the nets are however provided with windows allowing the passage downstream of a certain quantity of material.
  • the widths of the windows are adjusted so as to keep the material insufficiently upstream.
  • the material having reached the desired degree of defibration, most of the defibration work being obtained by a combination of compression and shearing effects in the compressed areas, in particular due to the fact that, in these zones, the material is entrained around the threads passing from one screw to another. It is thus possible to progressively defiberate the chips by reducing the width of the windows from one braking zone to the next.
  • correct defibration is obtained by passing through three or four sections with reverse pitch.
  • an important advantage lies in the fact that it is possible to carry out, inside the same machine, the bleaching of the dough during the defibration of the chips as well as the broad and a wringing to a degree at least 35% dryness.
  • washing of the dough is carried out at the same time as defibration, in the successive zones of the machine.
  • This therefore includes a number of successive defibration zones comprising a compression section and an inverted pitch section, and the sheath surrounding the screws is provided with filtering zones in the parts preceding the inverted pitch sections. It is in fact observed that the liquid phase which is expressed in the compression zones can go upstream in the less compressed zones, passing between the periphery of the threads and the internal wall of the sheath to the filtering zones where it is discharged.
  • the dough thus produced contains a certain number of impurities, in particular knots, heaps of fibers and small, insufficiently defibrated pieces called buchettes. This is why the dough also passes through a disintegrator which performs final defibration and then through various sorting devices.
  • the raw pulp is made up of fibers normally too coarse to be usable directly for the manufacture of paper and must therefore undergo a so-called refining treatment in a refining pile or a refiner. During this treatment, and in particular under the action of water, a so-called fibrillation effect is obtained which promotes the adhesion of the fibers to each other during the manufacture of paper.
  • cellulose fiber pulps can have other uses.
  • the pulps of fibers produced by the papermaking route serve as raw material for the manufacture of absorbent products of the cellulose wadding type or of molded products in which the fibers isolated by the defibration treatment are mixed with a thermosetting binder.
  • sorting and refining are carried out in very dilute suspension, which has no disadvantage in the manufacture of paper which in any case requires feeding the machines with a very dilute suspension in order to obtain a good fiber distribution.
  • non-paper applications it is advantageous to reduce as much as possible the content of the pulp in liquid, the elimination of which requires a great expenditure of energy.
  • the subject of the invention is a new process allowing the final defibration of the pulp by means better suited to the production of fiber pulp for non-paper use and which, moreover, requires simpler equipment and much less bulky and a much lower energy expenditure.
  • the new method according to the invention makes it possible to adapt much more flexibly to productions of medium importance.
  • the defibration treatment being carried out in a screw machine of known type, after having obtained the desired degree of defibration by passage through the first treatment zones, the scabs and fiber bundles are completely eliminated by passage of the material in at least two additional treatment zones, until a homogeneous paste consisting only of isolated fibers which have not undergone fibrillation is obtained.
  • the wood chips can be fed to the upstream orifice of the machine with a very small amount of water and, in particular, when the chips are soaked with water before defibration, as is usually the case, the quantity of liquid phase which they contain is generally sufficient, the material being able to be entrained from one treatment zone to another and defibrated under good conditions up to a 55% dryness.
  • the dough thus produced contains a certain quantity of fiber bundles and insufficiently defibrated sticks, yet the defibration treatment cannot be continued by further reducing the width of the windows because, in some cases, the quality of the dough would be reduced by excessive shortening of the fibers. This is why, when the fiber pulp produced is intended for the manufacture of paper, it is subjected to a refining operation by conventional means.
  • this passage into additional treatment zones does not replace refining because the fibrillation effect sought for paper pulps is not obtained, but, precisely, in non-paper applications, fibrillation is not necessary and can sometimes be harmful.
  • this type of machine also has the very advantageous advantage of also carrying out, if necessary, the elimination of most of the resin contained in the wood.
  • This elimination of the resin is particularly useful for obtaining absorbent materials of the cellulose wadding type.
  • this type of product was made from a chemical paste for which the cooking before was carried out with reagents chosen so as to effect the elimination of the resin at the same time as that of the lignin.
  • the chemical route also gave the advantage of providing a very fine paste devoid of buchettes.
  • chemical pulp is expensive and attempts have also been made to make absorbent materials from thermo-mechanical or mechanical-chemical pulp. In this case, the resin must be removed by a reagent, generally before the defibration treatment.
  • such pulps contain a certain amount of flossers which are not suitable for the usual uses of cellulose wadding and which, as said above, must be eliminated by means known in the paper industry.
  • the passage in the compression zones that is to say at the end of the drive sections and in the braking sections makes it possible to express the resin which dissolves in the liquid phase expressed at the same time and can be discharged with it through the filtration orifices provided upstream of the compressed zones.
  • This mechanical effect is amplified if a reagent promoting the detachment of the resin is introduced into the sheath.
  • a bleaching reagent such as a mixture of hydrogen peroxide and sodium peroxide, without sequestering agent, activates the elimination of the resin.
  • the bleaching reagent is, in this case, introduced from the first treatment zone at the start of defibering, which allows it to impregnate the chips in the first drive zone with the first pressure build-up.
  • the bleaching reagent is also introduced into the second treatment zone where the elimination of the resin is continued and the pulp is at the same time bleached.
  • the first two treatment zones with filtration orifices.
  • the pulp is concentrated in the first zone by eliminating part of the liquid phase with the resin and, in the second zone, a washing liquid can be injected which activates the elimination of impurities.
  • a certain quantity of bleaching reagent is allowed to pass downstream, which makes it possible to complete it in the following treatment zones so as to obtain, at the outlet of the machine, a defibrated, refined and bleached pulp, which is particularly interesting when making cellulose wadding.
  • the fiber pulp is mixed with a binder for the production of molded objects
  • the risk of clogging of the filtering walls is reduced and the speed of dehydration is increased.
  • the elimination of the resin and of the water promotes the mixing of the fibers with the binder.
  • FIG. 1 is a view in longitudinal section through the axis of a screw
  • FIG. 2 being a view in cross section along II, II of FIG. 1.
  • the machine comprises two screws 1 and 2 with parallel axes and provided with identical threads which penetrate one into the other.
  • a sheath 3 which envelops the two screws is provided at one end with a supply orifice 31 and at the other end with a discharge orifice 32. The two screws are rotated in the direction allowing, depending on the not threads, to entrain the material introduced through the orifice 31 to the outlet orifice 32.
  • the threads of the screws have various pitches which determine successive treatment zones, respectively I, II, III ... etc.
  • the machine comprises six treatment zones followed by a zone VII for discharging the treated material towards the outlet orifice 32.
  • Each treatment zone comprises a zone A whose pitch determines, as a function of the direction of rotation of the screw, the drive downstream of the material and a zone B whose pitch is reversed so as to determine a braking of the material and therefore compression at the end of zone A and in zone B.
  • the threads 11 and 21 of the screws in zone B are provided with openings 12, 22 forming windows which extend from the shaft of the screw to the periphery of the thread.
  • the width of the windows decreases when going downstream.
  • the windows can have a width comprised between 15 and 20 mm in the first braking section and from 4 to 5 mm at the exit of the last defibration zone, i.e. zone III or IV. This width is kept in the braking sections of the following zones V and VI.
  • orifices 33 generally placed just in front of the braking sections B1, B2, etc., that is to say in the compressed areas, make it possible to inject various reactants under pressure and, in the first two treatment zones 1 and II, filter parts 34 are provided in the sheath upstream of the compressed zones.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)

Abstract

1. Process for producing a pulp of cellulose fibres not to be used for paper-making, by passing wood chips into a pulping machine comprising at least two screws (1, 2) having identical threads meshing in one another and driven in rotation on the inside of a sleeve (3) provided with an upstream chip inflow orifice (31) and with a downstream pulped-material cutflow orifice (32), the threads (11, 21) of the screws (1, 2) having varied pitches determining a succession of processing zones (I, II etc.), each comprising a section (A) with a direct pitch for driving the material downstream and a section (B) with a reversed pitch for increasing pressure as a result of the braking of the material, the threads with reverse pitches being provided with apertures (12, 22) for the downstream passage of the material which has reached the desired degree of pulping, the sleeve (3) being provided with filtering parts (34) located upstream of the reverse-pitch braking sections (B), at least in the first two processing zones (I, II), in order to carry out drying of the material, characterised in that the material ist first brought to the desired degree of pulping by being passed through the first processing zones (I, II, III), which incorporate reverse-pitch sections (B) provided with apertures, the width of which decreases from one zone to the next to a width of the order of 4 to 5 mm, in that, at the same time, drying together with filtration is carried out to a degree of dryness of between 35% and 55%, and in that the shives and clusters of fibres are subsequently eliminated in the same machine, without reducing the length of the fibres and without carrying out any fibrillation, by passing the pulped and dried material through at least two additional processing zones (IV, V), which incorporate reverse-pitch braking sections provided with apertures having the same width of the order of 4 to 5 mm as in the last pulping zone (III), and a homegenous pulp consisting solely of isolated fibres which have not undergone any fibrillation is obtained at the outlet of the machine.

Description

L'invention a pour objet un procédé et une installation de fabrication d'une pâte de fibres cellulosique utilisable spécialement dans des domaines non papetiers sans autre traitement qu'un assèchement.The subject of the invention is a method and an installation for manufacturing a pulp of cellulosic fibers which can be used especially in non-paper fields without any treatment other than drying.

On connaît depuis longtemps un certain nombre de procédés de fabrication de pâte cellulosique, notamment à partir de copeaux de bois et qui consistent, par divers moyens, à désagréger les copeaux pour en isoler les fibres. Ces procédés ont été mis au point spécialement pour la fabrication de pâte à papier.A number of processes have been known for a long time for manufacturing cellulose pulp, in particular from wood chips and which consist, by various means, of breaking up the chips in order to isolate the fibers. These processes have been specially developed for the manufacture of paper pulp.

Pour obtenir l'isolement des fibres, on peut désagréger les copeaux par voie purement mécanique au moyen de meules, par exemple. On obtient alors les pâtes dites mécaniques. Cependant, il peut être intéressant d'essayer d'éliminer la lignine qui assure l'adhérence des fibres entre elles aux moyens de réactifs chimiques. Dans ce cas, les copeaux subissent une cuisson pendant un temps assez long dans des appareils appelés digesteurs permettant au réactif d'attaquer la li- gine qui se dissout dans la phase liquide. Si le traitement chimique est assez poussé pour obtenir l'isolement complet des fibres, on obtient les pâtes dites chimiques qui sont désintégrées facilement, par exemple par soufflage à l'air comprimé.To obtain the insulation of the fibers, the chips can be disaggregated purely mechanically by means of grinding wheels, for example. The so-called mechanical pastes are then obtained. However, it may be interesting to try to eliminate the lignin which ensures the adhesion of the fibers to each other by means of chemical reagents. In this case, the chips undergo cooking for a fairly long time in devices called digesters allowing the reagent to attack the ligin which dissolves in the liquid phase. If the chemical treatment is sufficiently advanced to obtain complete isolation of the fibers, the so-called chemical pulps are obtained which are easily disintegrated, for example by blowing with compressed air.

Cependant, on peut également combiner le traitement mécanique et le traitement chimique. On obtient alors les pâtes mi-chimiques qui font appel, dans un premier stade, à un réactif chimique attaquant la lignine puis, dans un second stade, à une énergie mécanique, généralement dans des appareils appelés défibreurs à disques.However, mechanical treatment and chemical treatment can also be combined. We then obtain semi-chemical pastes which use, in a first stage, a chemical reagent attacking lignin then, in a second stage, mechanical energy, generally in devices called disc shredders.

On peut également ramollir les copeaux avant le traitement mécanique par action d'un réactif chimique ou de vapeur d'eau à haute température et l'on obtient les pâtes dites mécano-chimiques et thermo-mécaniques.It is also possible to soften the chips before the mechanical treatment by the action of a chemical reagent or steam at high temperature and the so-called mechanical-chemical and thermo-mechanical pastes are obtained.

Dans tous les cas, la pâte obtenue à la fin du traitement de défibrage se présente sous la forme d'une suspension très diluée qui doit être lavée, blanchie puis essorée.In all cases, the paste obtained at the end of the defibration treatment is in the form of a very dilute suspension which must be washed, bleached and then wrung out.

La Société déposante à mis au point depuis quelques années un nouveau procédé et une nouvelle machine de défibrage des copeaux de bois. Cette machine décrite, en particulier dans le brevet français no 2319737 comprend au moins deux vis à filets identiques engrenant l'une dans l'autre et entrainées en rotation à l'intérieur d'un fourreau muni d'un orifice amont d'entrée des copeaux et d'un orifice aval de sortie de la matière défibrée; les filets des vis ont des pas variés qui déterminent une succession de zones de traitement comprenant chacune une section à pas direct dans laquelle la matière est entrainée vers l'aval et une section à pas inversé qui freine l'avancement de la matière et par conséquent détermine une montée en pression. Dans cette section à pas inversés, les filets sont cependant munis de fenêtres permettant le passage vers l'aval d'une certaine quantité de matière.Selon l'invention précédente, les largeurs des fenêtres sont réglées de façon à maintenir en amont la matière insuffisamment défibrée et à laisser passer vers l'aval la matière ayant atteint le degré de défibrage souhaité, la plus grande partie du travail de défibrage étant obtenue par une combinaison d'effets de compression et de cisaillement dans les zones comprimées, en particulier grâce au fait que, dans ces zones, la matière est entrainée autour des filets en passant d'une vis à l'autre. On peut ainsi réaliser progressivement le défibrage des copeaux en diminuant la largeur des fenêtres d'une zone de freinage à la suivante. Généralement, un défibrage correct est obtenu par passage dans trois ou quatre sections à pas inversé.The Depositing Company has been developing for a few years a new process and a new machine for defibrating wood chips. This machine described, in particular in French patent no. 2319737, comprises at least two identical threaded screws meshing in one another and rotated inside a sheath provided with an upstream inlet orifice for the chips and a downstream outlet for the defibrated material; the threads of the screws have varied pitches which determine a succession of treatment zones each comprising a direct pitch section in which the material is entrained downstream and an inverted pitch section which slows down the advancement of the material and consequently determines an increase in pressure. In this section with inverted steps, the nets are however provided with windows allowing the passage downstream of a certain quantity of material. According to the preceding invention, the widths of the windows are adjusted so as to keep the material insufficiently upstream. the material having reached the desired degree of defibration, most of the defibration work being obtained by a combination of compression and shearing effects in the compressed areas, in particular due to the fact that, in these zones, the material is entrained around the threads passing from one screw to another. It is thus possible to progressively defiberate the chips by reducing the width of the windows from one braking zone to the next. Generally, correct defibration is obtained by passing through three or four sections with reverse pitch.

D'autre part, un avantage important réside dans le fait qu'il est possible de réaliser à l'intérieur de la même machine le blanchiment de la pâte au cours du défibrage des copeaux ainsi que le large et un essorage jusqu'à un degré de siccité d'au moins 35%. Dans le document FR-A-2451 963, de lavage de la pâte est effectué en même temps que le défibrage, dans les zones successives de la machine. Celle-ci comprend donc un certain nombre de zones successives de défibrage comprenant une section de compression et une section à pas inversé, et le fourreau entourant les vis est muni de zones filtrantes dans les parties précédant les sections à pas inversé. On constate en effet que la phase liquide qui est exprimée dans les zones de compression peut remonter vers l'amont dans les zones moins comprimées en passant entre la périphérie des filets et la paroi interne du fourrreau jusqu'aux zones filtrantes où elle est évacuée.On the other hand, an important advantage lies in the fact that it is possible to carry out, inside the same machine, the bleaching of the dough during the defibration of the chips as well as the broad and a wringing to a degree at least 35% dryness. In document FR-A-2451 963, washing of the dough is carried out at the same time as defibration, in the successive zones of the machine. This therefore includes a number of successive defibration zones comprising a compression section and an inverted pitch section, and the sheath surrounding the screws is provided with filtering zones in the parts preceding the inverted pitch sections. It is in fact observed that the liquid phase which is expressed in the compression zones can go upstream in the less compressed zones, passing between the periphery of the threads and the internal wall of the sheath to the filtering zones where it is discharged.

La pâte ainsi produite contient un certain nombre d'impuretés et notamment des noeuds, des amas de fibres et des petits morceaux insuffisamment défibrés appelés buchettes. C'est pourquoi la pâte passe également dans un désintégrateur qui effectue un défibrage final puis dans divers appareils de triage.The dough thus produced contains a certain number of impurities, in particular knots, heaps of fibers and small, insufficiently defibrated pieces called buchettes. This is why the dough also passes through a disintegrator which performs final defibration and then through various sorting devices.

Par ailleurs, la pâte brute est constituée de fibres normalement trop grossières pour être utilisables directement pour la fabrication de papier et doit donc subir un traitement dit de raffinage dans une pile raffineuse ou un raffineur. Au cours de ce traitement, et notamment sous l'action de l'eau, on obtient un effet dit de fibrillation qui favorise l'adhérence des fibres entre elles au cours de la fabrication du papier.In addition, the raw pulp is made up of fibers normally too coarse to be usable directly for the manufacture of paper and must therefore undergo a so-called refining treatment in a refining pile or a refiner. During this treatment, and in particular under the action of water, a so-called fibrillation effect is obtained which promotes the adhesion of the fibers to each other during the manufacture of paper.

Toutes ces opérations qui viennent d'être décrites succintement ont été mises du point spécialement pour la fabrication du papier. Or les pâtes de fibres cellulosique peuvent avoir d'autres utilisations. En particulier, outre les utilisations chimiques de la cellulose ainsi produite, les pâtes de fibres réalisées par voie papetiére servent de matière première pour la fabrication de produits absorbant du genre ouate de cellulose ou de produits moulés dans lesquels les fibres isolés par le traitement de défibrage sont mélangés avec un liant thermo-durcissable.All these operations which have just been described briefly have been specially developed for the manufacture of paper. However, cellulose fiber pulps can have other uses. In particular, in addition to the chemical uses of the cellulose thus produced, the pulps of fibers produced by the papermaking route serve as raw material for the manufacture of absorbent products of the cellulose wadding type or of molded products in which the fibers isolated by the defibration treatment are mixed with a thermosetting binder.

Dans ces applications non papetières,.il est nécessaire également d'éliminer les impuretés, les ames de fibres et les buchettes. D'autre part, il faut généralement éliminer aussi la plus grande partie de la résine en particulier pour l'obtention de produits absorbants ou pour éviter le colmatage des installations d'élimination ultérieure de l'eau.In these non-papermaking applications, it is also necessary to remove impurities, fiber cores and buchettes. On the other hand, it is generally also necessary to remove most of the resin, in particular in order to obtain absorbent products or to avoid clogging of the installations for the subsequent removal of water.

Dans ce but, on a utilisé jusqu'à présent les méthodes connues pour la fabrication de la pâte à papier bien que dans ces autres applications, la pâte de fibres ne doive pas nécessairement avoir les mêmes propriétés. En particulier, si, pour obtenir le défibrage total de la pâte, on la fait passer dans des appareils analogues aux raffineurs classiques, on obtient un effet de fibrillation qui n'est pas nécessaire et peut même être gênant car il diminue la vitesse de déshydratation.For this purpose, hitherto known methods have been used for the manufacture of paper pulp, although in these other applications, the pulp of fibers need not necessarily have the same properties. In particular, if, in order to obtain the complete defibration of the dough, it is passed through devices similar to conventional refiners, a fibrillation effect is obtained which is not necessary and can even be annoying because it reduces the rate of dehydration .

Par ailleurs, le triage et le raffinage s'effectuent en suspension très diluée, ce qui n'a pas d'inconvénient dans la fabrication du papier qui nécessite de toute façon l'alimentation des machines par un'e suspension très diluée pour obtenir une bonne répartition des fibres. En revanche, dans les applications non papetières, il est intéressant de diminuer autant que possible la teneur de la pâte en liquide dont l'élimination nécessite une grande dépense d'énergie.Furthermore, sorting and refining are carried out in very dilute suspension, which has no disadvantage in the manufacture of paper which in any case requires feeding the machines with a very dilute suspension in order to obtain a good fiber distribution. On the other hand, in non-paper applications, it is advantageous to reduce as much as possible the content of the pulp in liquid, the elimination of which requires a great expenditure of energy.

L'invention a pour objet un nouveau procédé permettant d'effectuer le défibrage final de la pâte par des moyens mieux adaptés à la réalisation de pâte de fibres à utilisation non papetière et qui, en outre, nécessite un équipement plus simple et beaucoup moins encombrant et une dépense d'énergie bien moindre.The subject of the invention is a new process allowing the final defibration of the pulp by means better suited to the production of fiber pulp for non-paper use and which, moreover, requires simpler equipment and much less bulky and a much lower energy expenditure.

Par ailleurs, alors que les installations de fabrication de pâte à papier ne sont prévues que pour des productions très importantes, le nouveau procédé selon l'invention permet de s'adapter de façon beaucoup plus souple à des productions d'importance moyenne.Furthermore, while the pulp manufacturing facilities are only provided for very large productions, the new method according to the invention makes it possible to adapt much more flexibly to productions of medium importance.

Conformément à l'invention, le traitement de défibrage étant effectué dans une machine à vis de type connu, après avoir obtenu le degré de défibrage souhaité par passage dans les premières zones de traitement, on élimine complètement les buchettes et amas de fibres par passage de la matière dans au moins deux zones supplémentaires de traitement, jusqu'à obtention d'une pâte homogène constituée uniquement de fibres isolées n'ayant pas subi de fibrillation.In accordance with the invention, the defibration treatment being carried out in a screw machine of known type, after having obtained the desired degree of defibration by passage through the first treatment zones, the scabs and fiber bundles are completely eliminated by passage of the material in at least two additional treatment zones, until a homogeneous paste consisting only of isolated fibers which have not undergone fibrillation is obtained.

On a déjà indiqué plus haut que, dans une machine à vis du type décrit dans le brevet français 2 319 737, le traitement de défibrage est effectué progressivement par passage dans plusieurs zones de traitement constituées chacune d'une section d'entrainement à pas direct suivie d'une section de freinage munie de filets à pas inversé dans lesquels sont ménagées des fenêtres dont la largeur permet de contrôler le passage vers l'aval de la matière ayant atteint le degré de défibrage souhaité. Si l'on part de copeaux de bois, on peut atteindre le degré de défibrage d'une pâte normale par passage dans trois ou quatre zones de traitement. D'autre part, selon une caractéristique très intéressante de cette machine, les copeaux de bois peuvent être alimentés à l'orifice amont de la machine avec une très faible quantité d'eau et, en particulier, lorsque les copeaux sont imbibés d'eau avant le défibrage, comme c'est le cas habituellement, la quantité de phase liquide qu'ils contiennent est généralement suffisante, la matière pouvant être entrainée d'une zone de traitement à l'autre et défibrée dans de bonnes conditions jusqu'à un degré de siccité de 55%.It has already been indicated above that, in a screw machine of the type described in French patent 2,319,737, the defibration treatment is carried out gradually by passing through several treatment zones each consisting of a direct-pitch drive section. followed by a braking section provided with inverted pitch threads in which windows are provided whose width makes it possible to control the passage downstream of the material having reached the desired degree of defibration. If you start with wood chips, you can reach the degree of defibration of a normal pulp by passing through three or four treatment zones. On the other hand, according to a very interesting characteristic of this machine, the wood chips can be fed to the upstream orifice of the machine with a very small amount of water and, in particular, when the chips are soaked with water before defibration, as is usually the case, the quantity of liquid phase which they contain is generally sufficient, the material being able to be entrained from one treatment zone to another and defibrated under good conditions up to a 55% dryness.

Comme dans les autres procédés de défibrage mécaniques, la pâte ainsi réalisée contient une certaine quantité d'amas de fibres et de buchettes insuffisamment défibrées, or on ne peut poursuivre le traitement de défibrage en diminuant encore la largeur des fenêtres car, dans de cas, on diminuerait la qualité de la pâte par un raccourcissement excessif des fibres. C'est pourquoi, lorsque la pâte de fibres réalisée est destinée la fabrication de papier, on lui fait subir une opération de raffinage par des moyens classiques.As in the other mechanical defibration processes, the dough thus produced contains a certain quantity of fiber bundles and insufficiently defibrated sticks, yet the defibration treatment cannot be continued by further reducing the width of the windows because, in some cases, the quality of the dough would be reduced by excessive shortening of the fibers. This is why, when the fiber pulp produced is intended for the manufacture of paper, it is subjected to a refining operation by conventional means.

Or on a constaté que si l'on fait passer la pâte défibrée dans un certain nombre de zones de traitement supplémentaires sans changer la lar- geurdes fenêtres des sections de freinage à pas inversé, on parvient à éliminer complètement les buchettes sans diminuer de façon excessive la longueur des fibres. Cet effet surprenant peut s'expliquer par le fait que la longueur des fibres dépend essentiellement de la largeur des fenêtres et par conséquent n'est pas beaucoup modifiée si l'on ne diminue pas cette largeur dans les zones suivantes, et qu'en revanche, si l'on fait passer la pâte défibréee dans au moins deux zones de traitement supplémentaires, grâce au degré de siccité relativement élevé, les sections à pas inversés continuent à déterminer une montée en pression de la matière et par conséquent de soumettre les buchettes à un travail de cisaillement et de torsion sous pression qui permet de les éliminer complètement et d'obtenir à la sortie de la machine une pâte homogène constituée uniquement de fibres isolées.However, it has been found that if the defibrated pulp is passed through a certain number of additional treatment zones without changing the width of the windows of the braking sections with reverse pitch, it is possible to completely eliminate the nozzles without excessively reducing the length of the fibers. This surprising effect can be explained by the fact that the length of the fibers depends essentially on the width of the windows and therefore is not much modified if this width is not reduced in the following areas, and that on the other hand , if the defibrated pulp is passed through at least two additional treatment zones, thanks to the relatively high degree of dryness, the sections with inverted steps continue to determine an increase in pressure of the material and consequently to subject the buchettes to a work of shearing and torsion under pressure which makes it possible to eliminate them completely and to obtain at the exit of the machine a homogeneous paste made up only of isolated fibers.

Certes, ce passage dans des zones supplémentaires de traitement ne remplace pas le raffinage car on n'obtient pas l'effet de fibrillation recherché pour les pâtes à papier mais, précisément, dans les applications non papetières, la fibrillation n'est pas nécessaire et peut même, parfois, être néfaste. En revanche, il est particulièrement intéressant d'obtenir en continu une pâte de fibres dépourvue de buchettes et relativement sèche à la sortie d'une machine unique peu encombrante alimentée en copeaux de bois.Admittedly, this passage into additional treatment zones does not replace refining because the fibrillation effect sought for paper pulps is not obtained, but, precisely, in non-paper applications, fibrillation is not necessary and can sometimes be harmful. On the other hand, it is particularly advantageous to obtain continuously a pulp of fibers devoid of scraps and relatively dry at the outlet of a single space-saving machine supplied with wood chips.

Mais, ce type de machine présente également l'avantage très intéressant de réaliser également, en cas de besoin, l'élimination de la plus grande partie de la résine contenue dans le bois. Cette élimination de la résine est particulièrement utile pour l'obtention de matières absorbantes du genre ouate de cellulose. Jusqu'à présent, ce type de produit était réalisé à partir d'une pâte chimique pour laquelle la cuisson avant été effecutée avec des réactifs choisis de façon à effectuer l'élimination de la résine en même temps que celle de la lignine. La voie chimique donnait en outre l'avantage de fournir une pâte très fine dépourvue de buchettes. Cependant, la pâte chimique est onéreuse et on avait également cherché à réaliser des matières absorbantes à partir d'une pâte thermo-mécanique ou mécano-chimique. Dans ce cas, la résine doit être éliminée par un réactif, généralement avant le traitement de défibrage. Cependant, de telles pâtes contiennent une certaine quantité de buchettes qui ne conviennent pas aux utilisations habituelles de la ouate de cellulose et qui, comme on l'a dit plus haut, doivent être éliminées par les moyens connus dans l'industrie papetière.However, this type of machine also has the very advantageous advantage of also carrying out, if necessary, the elimination of most of the resin contained in the wood. This elimination of the resin is particularly useful for obtaining absorbent materials of the cellulose wadding type. Until pre sent, this type of product was made from a chemical paste for which the cooking before was carried out with reagents chosen so as to effect the elimination of the resin at the same time as that of the lignin. The chemical route also gave the advantage of providing a very fine paste devoid of buchettes. However, chemical pulp is expensive and attempts have also been made to make absorbent materials from thermo-mechanical or mechanical-chemical pulp. In this case, the resin must be removed by a reagent, generally before the defibration treatment. However, such pulps contain a certain amount of flossers which are not suitable for the usual uses of cellulose wadding and which, as said above, must be eliminated by means known in the paper industry.

Or on a constaté que, lorsque le traitement de défibrage est effectué dans une machine à plusieurs vis, si l'on utilise comme matière première des copeaux de bois résineux dont l'âge par rapport à l'époque de la coupe est choisi de façon que la résine se décolle des canaux qui la contienne, on peut effectuer l'élimination de la plus grande partie de la résine par voie mécanique en même temps que le défibrage dans les deux premières zones de traitement.However, it has been found that, when the defibration treatment is carried out in a machine with several screws, if resinous wood shavings are used as raw material whose age relative to the time of cutting is chosen so as the resin peels off from the channels which contain it, the removal of most of the resin can be carried out mechanically at the same time as defibration in the first two treatment zones.

En pratique, on doit traiter des copeaux de bois ayant un âge inférieur à trois jours ou bien d'environ six mois ou plus. En effet, dans le premier cas, la résine n'est pas encore devenue très visqueuse et peut s'échapper des canaux et, dans le second cas, la résine est devenue au contraire dure et peut se décoller de la paroi des canaux.In practice, wood chips that are less than three days old or about six months or more should be treated. In fact, in the first case, the resin has not yet become very viscous and can escape from the channels and, in the second case, the resin has, on the contrary, become hard and can come off from the wall of the channels.

. Ainsi, le passage dans les zones de compression, c'est-à-dire à la fin des sections d'entraine- ment et dans les sections de freinage permet d'exprimer la résine qui se dissout dans la phase liquide exprimée en même temps et peut être évacuée avec elle par les orifices de filtration de ménagés en amont des zones comprimées.. Thus, the passage in the compression zones, that is to say at the end of the drive sections and in the braking sections makes it possible to express the resin which dissolves in the liquid phase expressed at the same time and can be discharged with it through the filtration orifices provided upstream of the compressed zones.

Alors que, normalement, l'expulsion de la résine par compression devrait nécessiter une pression de l'ordre de 500 bars, on constate que, dans une machine à plusieurs vis, le même résultat est obtenu avec une pression de 150 à 200 bars seulement. En effet, le traitement mécanique de défibrage auquel sont soumis les copeaux dans les zones comprimées permet, par l'effet combiné de cisaillement, de compression et de pression que l'on obtient, de décoller la résine des canaux en petites particules qui se mélangent à la phase liquide et s'évacuent avec elles.While, normally, the expulsion of the resin by compression should require a pressure of the order of 500 bars, it is found that, in a machine with several screws, the same result is obtained with a pressure of only 150 to 200 bars . In fact, the mechanical defibration treatment to which the shavings are subjected in the compressed areas allows, by the combined shearing, compression and pressure effect that is obtained, to loosen the resin from the channels into small particles which mix in the liquid phase and evacuate with them.

Cet effet mécanique est amplifié si l'on introduit dans le fourreau un réactif favorisant le décollement de la résine.This mechanical effect is amplified if a reagent promoting the detachment of the resin is introduced into the sheath.

Or on a constanté que l'introduction d'un réactif de blanchiment tel qu'un mélange d'eau oxygénée et de peroxyde de sodium, sans agent séquestrant activait l'élimination de la résine. On notera que le réactif de blanchiment est, dans ce cas, introduit dès la première zone de traitement au début du défibrage, ce qui lui permet d'imprégner les copeaux dans la première zone d'entrai- nement avec la première montée en pression. On introduit cependant également le réactif de blan - chiment dans la seconde zone de traitement où l'on continue l'élimination de la résine et où la pâte est en même temps blanchie.However, it has been observed that the introduction of a bleaching reagent such as a mixture of hydrogen peroxide and sodium peroxide, without sequestering agent, activates the elimination of the resin. It will be noted that the bleaching reagent is, in this case, introduced from the first treatment zone at the start of defibering, which allows it to impregnate the chips in the first drive zone with the first pressure build-up. However, the bleaching reagent is also introduced into the second treatment zone where the elimination of the resin is continued and the pulp is at the same time bleached.

Il est intéressant également de munir d'orifices de filtration les deux premières zones de traitement. De la sorte, on réalise dans la première zone une concentration de la pâte en éliminant une partie de la phase liquide avec la résine et, dans la seconde zone, on peut injecter un liquide de lavage qui active l'élimination des impuretés. Cependant, on laisse passer vers l'aval une certaine quantité de réactif de blanchiment qui permet de terminer celui-ci dans les zones de traitement suivantes de façon à obtenir à la sortie de la machine une pâte défibrée, raffinée et blanchie, ce qui est particulièrement intéressant lorsque l'on réalise de la ouate de cellulose.It is also advantageous to provide the first two treatment zones with filtration orifices. In this way, the pulp is concentrated in the first zone by eliminating part of the liquid phase with the resin and, in the second zone, a washing liquid can be injected which activates the elimination of impurities. However, a certain quantity of bleaching reagent is allowed to pass downstream, which makes it possible to complete it in the following treatment zones so as to obtain, at the outlet of the machine, a defibrated, refined and bleached pulp, which is particularly interesting when making cellulose wadding.

D'autres réactifs chimiques peuvent également être utilisés pour favoriser l'élimination de la résine. C'est ainsi que, par exemple, on a constaté qu'il était intéressant de faire subir aux copeaux un pré-traitement de sulfonation avant le traitement de défibrage. On peut par exemple effectuer un traitement court avec un mono-sulfite ou bi-sulfite. Les copeaux ayant subit cette sulfonation préalable sont introduits dans la première zone de traitement de la machine où l'on injecte également un liquide de lavage. On peut ainsi effectuer un rinçage dans la première zone d'entrainement puis, après la première étape de défibrage effectuée dans la première section de freinage, un blanchiment dans la seconde zone de traitement et éventuellement dans les zones suivantes. Avant la sortie de la machine, un rinçage final peut être effectué dans la dernière zone de traitement.Other chemical reagents can also be used to promote the removal of the resin. Thus, for example, it was found that it was advantageous to subject the chips to a sulfonation pretreatment before the defibration treatment. One can for example carry out a short treatment with a mono-sulfite or bi-sulfite. The shavings having undergone this prior sulfonation are introduced into the first treatment zone of the machine where a washing liquid is also injected. It is thus possible to carry out a rinsing in the first training zone then, after the first defibering step carried out in the first braking section, a bleaching in the second treatment zone and possibly in the following zones. Before leaving the machine, a final rinse can be carried out in the last treatment area.

Chaque section à pas inversé, par la compression de la matière qu'elle provoque, détermine la formation d'un bouchon continu étanche même à des gaz. C'est pourquoi l'on peut également utiliser, un solvant volatil pour activer l'élimination de la résine.Each inverted step section, by the compression of the material it causes, determines the formation of a continuous plug, even gas tight. This is why it is also possible to use a volatile solvent to activate the elimination of the resin.

L'obtention à la sortie de la machine d'un produit relativement sec est particulièrement avantageuse dans le cas des applications non papetières pour lesquelles le séchage sur toile filtrante n'est pas adapté.Obtaining a relatively dry product at the outlet of the machine is particularly advantageous in the case of non-paper applications for which drying on a filter cloth is not suitable.

En effet, généralement, on préfère utiliser comme matière première un pâte de fibres asséchée dans des filtres presses et se présentant par conséquent sous la forme de plaques. Les fibres sont détachées de ces plaques par voie mécanique et forment une bourre qui est ensuite cardée. Les parties non défibrées doivent être éliminées par un triage à sec, ce qui diminue le rendement global. Grâce au procédé selon l'invention au contraire, on obtient une pâte déjà raffinée et déjà essorée qui ne nécessite qu'un séchage complémentaire, par exemple, par air chaud pour l'obtention d'une bourre sèche pouvant être cardée de façon classique mais ne contenant pas de parties non défibrées.Indeed, generally, it is preferred to use as raw material a pulp of fibers dried in filter presses and therefore being in the form of plates. The fibers are mechanically detached from these plates and form a wad which is then carded. The non-defibrated parts must be eliminated by a dry sorting, which decreases the overall yield. Thanks to the process according to the invention on the contrary, an already refined and already wrung dough is obtained which requires only additional drying, for example, by hot air to obtain a dry fluff for before being carded in a conventional manner but not containing non-defibrated parts.

Dans le cas où la pâte de fibres est mélangée à un liant pour la réalisation d'objets moulés, il est possible d'utiliser directement la pâte sortant de la machine avec le degré de siccité de 35% au moins et d'effectuer le séchage final par pression dans un moule à paroi filtrante. En effectuant le raffinage sans effet de fibrillation, on diminue le risque de colmatage des parois filtrantes et l'on augmente la vitesse de déshydratation. D'autre part, l'élimination de la résine et de l'eau favorise le mélange des fibres avec le liant.In the case where the fiber pulp is mixed with a binder for the production of molded objects, it is possible to directly use the pulp leaving the machine with the degree of dryness of at least 35% and to carry out the drying. final by pressure in a mold with a filtering wall. By carrying out the refining without the fibrillation effect, the risk of clogging of the filtering walls is reduced and the speed of dehydration is increased. On the other hand, the elimination of the resin and of the water promotes the mixing of the fibers with the binder.

Sur les figures, on a représenté schématiquement et à titre d'exemple une machine pour la réalisation du procédé. La figure 1 est une vue en coupe longitudinale par l'axe d'une vis, la figure 2 étant une vue en coupe transversale selon II,II de la figure 1.The figures show schematically and by way of example a machine for carrying out the process. FIG. 1 is a view in longitudinal section through the axis of a screw, FIG. 2 being a view in cross section along II, II of FIG. 1.

La machine comprend deux vis 1 et 2 à axes parallèles et munies de filets identiques qui pénètrent l'un dans l'autre. Un fourreau 3 qui enveloppe les deux vis est muni à une extrémité d'un orifice d'alimentation 31 et à l'autre extrémité d'un orifice d'évacuation 32. Les deux vis sont entrainées en rotation dans le sens permettant, selon le pas des filets, d'entraîner la matière introduite par l'orifice 31 jusqu'à l'orifice de sortie 32.The machine comprises two screws 1 and 2 with parallel axes and provided with identical threads which penetrate one into the other. A sheath 3 which envelops the two screws is provided at one end with a supply orifice 31 and at the other end with a discharge orifice 32. The two screws are rotated in the direction allowing, depending on the not threads, to entrain the material introduced through the orifice 31 to the outlet orifice 32.

Les filets des vis ont des pas variés qui déterminent des zones de traitement successives, respectivement I, II, III ... etc. Dans l'exemple représenté, la machine comprend six zones de traitement suivies d'une zone VII d'évacuation de la matière traitée vers l'orifice de sortie 32.The threads of the screws have various pitches which determine successive treatment zones, respectively I, II, III ... etc. In the example shown, the machine comprises six treatment zones followed by a zone VII for discharging the treated material towards the outlet orifice 32.

Chaque zone de traitement comprend une zone A dont le pas détermine, en fonction du sens de rotation de la vis, l'entrainement vers l'aval de la matière et une zone B dont le pas est inversé de façon à déterminer un freinage de la matière et par conséquent une compression à la fin de la zone A et dans la zone B.Each treatment zone comprises a zone A whose pitch determines, as a function of the direction of rotation of the screw, the drive downstream of the material and a zone B whose pitch is reversed so as to determine a braking of the material and therefore compression at the end of zone A and in zone B.

Comme représenté sur la figure 2, les filets 11 et 21 des vis dans la zone B sont munis d'ouvertures 12, 22 formant des fenêtres qui s'étendent depuis l'arbre dela vis jusqu'à la périphérie du filet. La largeur des fenêtres diminue lorsque l'on va vers l'aval. C'est ainsi que, par exemple, si l'on traite une pâte ayant subi un pré-traitement d'imprégnation par un réactif, pour le ramolissement des copeaux, les fenêtres peuvent avoir une largeur comprise entre 15 et 20 mm dans la première section de freinage et de 4 à 5 mm à la sortie de la dernière zone de défibrage, c'est-à-dire la zone III ou IV. Cette largeur est conservée dans les sections de freinage des zones suivantes V et VI.As shown in FIG. 2, the threads 11 and 21 of the screws in zone B are provided with openings 12, 22 forming windows which extend from the shaft of the screw to the periphery of the thread. The width of the windows decreases when going downstream. Thus, for example, if one treats a paste having undergone a pretreatment of impregnation with a reagent, for the softening of the chips, the windows can have a width comprised between 15 and 20 mm in the first braking section and from 4 to 5 mm at the exit of the last defibration zone, i.e. zone III or IV. This width is kept in the braking sections of the following zones V and VI.

D'autre part, des orifices 33, placés généralement, juste en avant des sections de freinage B1, B2, etc... , c'est-à-dire dans les zones comprimées, permettent d'injecter sous pression divers réactifs et, dans les deux premières zones de traitement 1 et Il des parties filtrantes 34 sont ménagées dans le fourreau en amont des zones comprimées.On the other hand, orifices 33, generally placed just in front of the braking sections B1, B2, etc., that is to say in the compressed areas, make it possible to inject various reactants under pressure and, in the first two treatment zones 1 and II, filter parts 34 are provided in the sheath upstream of the compressed zones.

Ainsi, on a pu traiter dans une telle machine des copeaux de bois résineux de plus de six mois ayant subi un pré-traitement de sulfonation avant leur introduction dans la machine. Par l'orifice 33, on a introduit un liquide de lavage de façon à effectuer un rinçage dans la zone AI, le liquide usé étant évacué par la partie filtrante 34. Par l'orifice 35 de la zone Il on a introduit un réactif de blanchiment, par exemple un mélange d'eau oxygénée et de soude, dans une proportion de l'ordre de 2% du poids de matière sèche. Un deuxième essorage est effectué dans une partie filtrante du fourreau, jusqu'à un degré de siccité de 35%, qui se maintient ensuite jusqu'à la sortie de la machine.Thus, it was possible to treat in such a machine coniferous wood chips of more than six months having undergone a pre-treatment of sulfonation before their introduction into the machine. By the orifice 33, a washing liquid was introduced so as to carry out a rinsing in the zone AI, the spent liquid being evacuated by the filtering part 34. By the orifice 35 in the zone II a reagent was introduced. bleaching, for example a mixture of hydrogen peroxide and sodium hydroxide, in a proportion of the order of 2% of the weight of dry matter. A second spin is carried out in a filtering part of the barrel, to a dryness level of 35%, which is then maintained until it leaves the machine.

A la sortie de la deuxième zone de traitement, on avait évacué par des parties filtrantes la plus grande partie de la résine puisqu'il n'en restait plus que 0,7% du poids de matière sèche. La pâte obtenue à la sortie de la machine était com- plètementdéfibrée et contenait environ 35% de fibres longues passant au tamis de 18 MESH et 35% de fibres courtes passant au tamis de 48 MESH. Grâce à l'élimination de la résine, cette pâte était particulièrement adaptée à la fabrication d'une matière absorbante puisque son coefficient d'absorption défini selon les normes en vigueur n'était que de 10.At the exit from the second treatment zone, most of the resin had been removed by filtering parts since only 0.7% of the weight of dry matter remained. The pulp obtained from the machine was completely defibrated and contained approximately 35% of long fibers passing through the 18 MESH sieve and 35% of short fibers passing through the 48 MESH sieve. Thanks to the elimination of the resin, this paste was particularly suitable for the manufacture of an absorbent material since its absorption coefficient defined according to the standards in force was only 10.

Bien entendu, l'invention définie par les revendications ne se limite pas seulement à ce mode de réalisation décrit seulement à titre d'exemple, ni aux seules applications qui ont été citées. C'est ainsi que les pâtes de fibres ainsi réalisées pourraient également servir de matière première pour des produits non tissés.Of course, the invention defined by the claims is not limited only to this embodiment described only by way of example, nor only to the applications which have been mentioned. This is how the fiber pulps thus produced could also serve as a raw material for nonwoven products.

Claims (11)

1. Process for producing a pulp of cellulose fibres not to be used for paper-making, by passing wood chips into a pulping machine comprising at least two screws (1, 2) having identical threads meshing in one another and driven in rotation on the inside of a sleeve (3) provided with an upstream chip inflow orifice (31) and with a downstream pulped-material outflow orifice (32), the threads (11, 21) of the screws (1, 2) having varied pitches determining a succession of processing zones (I, II etc.), each comprising a section (A) with a direct pitch for driving the material downstream and a section (B) with a reversed pitch for increasing pressure as a result of the braking of the material, the threads with reverse pitches being provided with apertures (12,22) for the downstream passage of the material which has reached the desired degree of pulping, the sleeve (3) being provided with filtering parts (34) located upstream of the reverse- pitch braking sections (B), at least in the first two processing zones (I, II), in order to carry out drying of the material, characterised in that the material ist first brought to the desired degree of pulping by being passed through the first processing zones (I, II, III), which incorporate reverse-pitch sections (B) provided with apertures, the width of which decreases from one zone to the next to a width of the order of 4 to 5 mm, in that, at the same time, drying together with filtration is carried out to a degree of dryness of between 35% and 55%, and in that the shives and clusters of fibres are subsequently eliminated in the same machine, without reducing the length of the fibres and without carrying out any fibrillation, by passing the pulped and dried material through at least two additional processing zones (IV, V), which incorporate reverse-pitch braking sections provided with apertures having the same width of the order of 4 to 5 mm as in the last pulping zone (III), and a homegenous pulp consisting solely of isolated fibres which have not undergone any fibrillation is obtained at the outlet of the machine.
2. Process for producing a pulp of fibres according to Claim 1, characterised in that the machine is supplied with resinous wood chips, of which the age in relation to the cutting period is selected so that the resin detaches from the channels containing it, and in that most of the resin is eliminated mechanically at the same time as pulping in the first two processing zones (I, 11).
3. Process for producing a pulp of fibres according to Claim 2, characterised in that a bleaching reagent is injected at least into the first drive section (A1), to assist the detachment of the resin and at the same time bleach the pulp during the pulping operation.
4. Process for producing a pulp of fibres according to one of Claims 2 and 3, characterised in that a washing liquid is injected into the sleeve (3) downstream of the first processing zone (I), to carry out washing at least in the second drive section (A2), the spent liquid being discharged via the filtration orifices (34) made in the sleeve (3).
5. Process for producing a pulp of fibres according to Claim 1, characterised in that a volatile solvent is injected into the sleeve (3) downstream of the first reverse-pitch braking section (B1
6. Production process according to Claim 1, characterised in that the material is passed through at least five processing zones.
7. Production process according to Claim 3, characterised in that the injected bleaching reagent is a mixture of oxygenated water and an alkaline product.
8. Production process according to Claim 1, characterised in that before being supplied to the pulping machine, the chips are subjected to a prior sulphonation treatment.
9. Production process according to Claim 1, characterised in that the age of the wood chips is less than three days after cutting, so that the resin contained has remained fluid.
10. Production process according to Claim 1, characterised in that the age of the wood chips is at least six months after cutting, so that the resin contained has hardened.
11. Machine for producing a pulp of cellulose fibres not to be used for paper-making, comprising at least two screws (1, 2) having identical threads meshing in one another and driven in rotation on the inside of a sleeve (3) provided with an upstream chip inflow orifice (31) and with a downstream pulped-material outflow orifice (32), the threads (11, 21) of the screws (1, 2) having varied pitches determining a succession of processing zones (1, II, etc.), each comprising a section (A) with a direct pitch for driving the material downstream and a section (B) with a reverse pitch for increasing pressure as a result of the braking of the material, the reverse-pitch threads being provided with apertures (12, 22) for the downstream passage of the material which has reached the desired degree of pulping, the sleeve (3) being provided with filtering parts (34) located upstream of the reversepitch braking sections (B), at least in the first two processing zones (I, II), to carry out drying of the material, characterised in that it incorporates, downstream of the first chip-pulping and drying part, a second part for eliminating the shives and clusters of fibres without any fibrillation effect, the first part comprising at least three pulping zones, in which the reverse-pitch sections (B1, B2, B3) are provided with apertures (12, 22), the width of which decreases from one section to the next to a width of the order of 4 to 5 mm in the last section (B3), and the second part comprising at least two additional processing zones (IV, V) incorporating the reverse-pitch sections (B4, B5) provided with apertures (12, 22) having the same width of the order of 4to 5 mm as in the last pulping zone (III).
EP82401346A 1981-07-20 1982-07-20 Method of making a cellulosic fibre pulp for non paperlike applications Expired EP0070782B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82401346T ATE15918T1 (en) 1981-07-20 1982-07-20 PROCESS FOR MAKING A CELLULOSIC PULP FOR NON-PAPER-LIKE APPLICATIONS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8114054 1981-07-20
FR8114054A FR2509766A1 (en) 1981-07-20 1981-07-20 PROCESS FOR PRODUCING CELLULOSIC FIBER PASTE FOR NON-PAPER USE

Publications (2)

Publication Number Publication Date
EP0070782A1 EP0070782A1 (en) 1983-01-26
EP0070782B1 true EP0070782B1 (en) 1985-10-02

Family

ID=9260656

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Application Number Title Priority Date Filing Date
EP82401346A Expired EP0070782B1 (en) 1981-07-20 1982-07-20 Method of making a cellulosic fibre pulp for non paperlike applications

Country Status (5)

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EP (1) EP0070782B1 (en)
AT (1) ATE15918T1 (en)
CA (1) CA1193405A (en)
DE (1) DE3266691D1 (en)
FR (1) FR2509766A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2625645B1 (en) * 1988-01-13 1991-07-05 Wogegal Sa PROCESS AND INSTALLATION FOR PRODUCING A PRODUCT AS A CULTURE SUPPORT
EP0979895A1 (en) * 1998-08-12 2000-02-16 Instituut Voor Agrotechnologisch Onderzoek (Ato-Dlo) Method and device for refining fibres
GB2441748A (en) * 2006-09-13 2008-03-19 Freeland Horticulture Ltd Apparatus and process for the treatment of plant waste to produce growing media
FR2980333B1 (en) * 2011-09-26 2014-08-29 Florentaise INSTALLATION FOR PREPARING WOOD FIBERS FOR A CULTURE SUBSTRATE
FR2980332B1 (en) * 2011-09-26 2013-10-11 Florentaise PROCESS FOR PREPARING WOOD FIBERS FOR A CULTURE SUBSTRATE
CN107541977A (en) * 2017-09-30 2018-01-05 河北天正筛选制浆设备有限公司 A kind of multiscrew high concentration displacement washing defibrination discongests device and slurry washing system

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2436844A2 (en) * 1978-09-19 1980-04-18 Creusot Loire Converting lignocellulose material into fibre pulp - for paper-making, by introducing bleach whilst the lignocellulose is being broken down
FR2451963A1 (en) * 1979-03-22 1980-10-17 Creusot Loire PROCESS AND INSTALLATION FOR PREPARING AND WASHING A PAPER PULP FROM A LIGNOCELLULOSIC MATERIAL REDUCED IN PIECES

Also Published As

Publication number Publication date
ATE15918T1 (en) 1985-10-15
EP0070782A1 (en) 1983-01-26
DE3266691D1 (en) 1985-11-07
FR2509766A1 (en) 1983-01-21
CA1193405A (en) 1985-09-17
FR2509766B1 (en) 1983-11-10

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