FR2529593A1 - METHOD AND APPARATUS FOR PROCESSING RECOVERY PAPER - Google Patents

Abstract

A. THE INVENTION RELATES TO A PROCESS AND AN APPARATUS FOR TREATMENT OF RECOVERY PAPER BY DISINTEGRATION AND SUSPENSION IN A CRUSHER 12, THEN SENT TO A VIRTUAL FLOW 1. B. THE PROCESS IS CHARACTERIZED AS A DIRECTLY SENT A PART OF THE SUSPENSION IN A CONDITION THAT DOES NOT ALLOW THE PUMPING OF THE CRUSHER 12 TO VIRTUAL FLOW 1 OR THE SUSPENSION IS DILUTED. C. THE INVENTION IS APPLICABLE TO THE TREATMENT OF RECOVERY PAPER.

Description

Method and apparatus for processing recovery paper

ration ".

  The subject of the invention is a method of treating recovery paper by disintegrating and suspending it in a mill with a high concentration and using a vortex flow formed in a device (centrifugal classifier) having a closed vessel which essentially presents a form of revolution by a rotor essentially arranged in the form of a paddle wheel, a fraction enriched with heavy products being extracted on the radial edge of the flow and a fraction of finished paste being extracted at the axial end of the flow o the rotor which produces this swirling flow is mounted via a sieve closely adjacent to the rotor,

  the average concentration in the whirlpool flow

  being between 3.5 and 7%.

  The invention extends to judicious apparatus for

  the implementation of the process.

  In the preparation facilities established at

  At present, according to the state of the art, an appa-

  important role works according to a

  operating mode designated as that of a classi-

  Centrifugal indicator and a secondary product crusher

  In this unit, a whirlpool flow

  is produced by a paddlewheel in a closed tank

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  having a form of revolution, this rotating flow

  around a horizontal axis and the impeller being

  with a coaxial axis of rotation.

  billonnaire allows, on the one hand, to draw on the

  flow tower in the radial direction a fraction

  enriched with heavy impurities and, on the other hand,

  extract an extraction tube in the core of the vortex flow where a fraction enriched in light impurities accumulates, this fraction being able to be evacuated from the apparatus by the tube by carrying out a dilution In addition, the separation of a paste finished by means of a sieve

  outside the last vortex flow

  the paddle wheel, this screen being generally flat and arranged perpendicularly to the axis of rotation of the

  impeller and vortex flow.

  However, the product sent to this centrifugal classifier is a fiber suspension already purified in advance and prepared with recovery paper. This is described in GB-PS 1 340 998 referring to Figure 3 of this document. this is followed by the use of a mill which also functions according to the principle of vortex flow and in which, at the center of the vortex flow, packaging products, especially string and strips, are extracted.

  other impurities capable of spinning, extrac-

  This is done in the form of continuous tow by means of a device called a filament winder. The fraction purified in advance is extracted from the fiber suspension.

  from a separate extraction chamber, by means of

  a sieve arranged behind the rotor.

  Other methods known at the present time, which avoid the extraction of the tow with the device known as a pile winder, involve the assembly of at least one other classifier between the mentioned mill and the centrifugal classifier, in particular to separate the

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  impurities with a large surface which can be spun before being sent in the centrifugal classifier. For this purpose, very large rotating drums are preferably used.

  around a horizontal axis and having a perimeter wall

  However, these drums are very expensive because they have to be very

  On the other hand, the replacement of the extractive

  Initial filtration of the tow is becoming more and more of a necessity, as this method of extraction has a very strong tendency to cause irregularities in operation and greatly hampers the whole process of treatment as a weak point. is possible with this method of extracting the tow that if it is provided for this a service operator

  particular who conducts surveillance.

  Under these conditions, the object of the invention is to create a treatment method ensuring an operation

  safer, this process also avoiding the conventional drums

  horizontal estimators mentioned above which are

very bulky and expensive.

  To this end, the invention relates to a method of the type mentioned in the preamble, this process being characterized in that a part of the suspension, enriched with detritus, if necessary slightly diluted, is sent into a state which does not allow pumping. , with a concentration

  more than 8%, without sieving, directly and by

  discontinuous grinding mills at the vortex flow

  re, in which the dilution liquid is introduced

plementary.

  Particularly advantageous embodiments

  The process according to the invention is characterized in that the other part of the dilute suspension is also sent from the mill to the vortex flow, the dilution liquid is introduced into the core of the vortex flow or at least in the immediate vicinity. A particularly advantageous device for the implementation of the method is characterized in that the suspension is fed into the vortex flow at the axial end of this flow.

further away from the rotor.

  According to the invention, one implements

  an entirely new method of operation of the sepa-

  In this case, a material formed by fractional and unpurified recovery paper is fed to the apparatus by batch charges with a very high concentration which, at least at times,

  gives a consistency that does not even allow pumping.

  This avoids all the intermediate purification stages which would otherwise have been arranged in front of the centrifugal classifier mentioned above. Thus, a treatment process is obtained which uses a very compact device and which is then of safer operation. The subsequent stages of purification finer, which were customary in the state of the art, are naturally

  also provided in the case of the invention.

  As diluting liquid it is possible, in addition to water, also to use at least a part of the suspension

  taken from the crusher, this suspension being classi-

in advance and diluted.

  The invention will be better understood with regard to the

  In the drawing, the single FIGURE is an overall view of an apparatus for illustrating the invention.

  the implementation of the method according to the invention.

  In the figure, the grinder is designated by 12 and 1 by the classifier mounted thereafter, the latter creating a swirling flow rotating around a

  horizontal axis (see current lines) The classifi-

  1, which constitutes the turbulent flow apparatus

  The grinder chamber 12 is then directly mounted following the mill 12 and is connected thereto by a short discharge pipe of large cross-section. The mill vessel comprises a circulation member 16 mounted on its bottom wall 28. this member being provided with fins

  agitators 17 This circulator 16 rotates around

  turn of an axis 26 which is inclined only slightly on the vertical, that is to say at a small acute angle The lower part of the tank 12 tapers and comprises a discharge chamber 29 separated by a sieve 18 of the remainder of this part of the tank A completed dough discharge pipe 14 and a pipe

  dilution water 37 are connected to the evaluation chamber

  cuation 29 The sieve 18 is inclined on the horizontal of

  the angle at which the circulation member is inclined

  born on the vertical Since the conduct of evaluation

  cuation 15 must also ensure, especially the evacuation, heavy products, that is to say the impurities with a large volume and a high specific weight, this pipe is connected to the part of the lower zone of the tank located at lowest level The same is true for the connection of the exhaust pipe

  of finished dough 14 to the evacuation chamber 29.

  In the device described, a high concentration of the product in the mill 12 is preferably provided,

  this concentration may reach 15 to 20%,

  approximately 16% can thus provide a tank of relatively low volume To improve the conditions

  of extraction, it is then planned to send by the

  dilution of the dilution water 37 of the dilution water in the evacuation chamber 29 and create therein a lower consistency corresponding to a concentration

8%.

  In the exemplary embodiment considered, the driving

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  The finished dough discharge 14 and the other discharge line 15 are respectively provided with a valve for closing. It is possible to collect the finished dough continuously or periodically, while the discharge pipe 15 planned for products

  heavy duty must be opened periodically.

  We have again shown how the paper of recovery

  ration was brought to the shredder by means of a conveyor

  The liquid is fed via a pipe 36.

  The drive control of the drive member

  16 of the mill 12 is provided by a motor 22 by means of drive pulleys 31, 25 by means of belts This control can also be provided by an articulated shaft The control of the valves 24 and 35 can be provided by servomotors hydraulic Such

  Servomotor is shown at 27 for valve 35.

  For the circulation member 16, it is necessary to use

  A realization with stirring vanes 17

  arranged in the form of a multi-threaded screw.

  besides, that the most appropriate

  door, on the underside of a plate 33 of the circulation member 16 carrying the stirring fins, ribs 32 for mixing the suspension, in the

  lowest part of the tank, especially in the chamber.

  29, with the water supplied by the dilution water pipe 37 That no noticeable dilution of the suspension in the mill zone occurs

  located above the plateau 33, it separates practically

  a dilution zone, situated below it and comprising the evacuation chamber 29, of the remainder of this part of the mill. The action for circulating the ribs 32 remains limited to the zone mentioned first, in possibly using additional retaining elements arranged on the plate 33, for example retaining walls arranged next to the ribs 32 to

  the outside of these in the radial direction.

  It is worth mentioning again that the strings

  and yarn used for the packaging of recycled paper

  unsorted feed introduced into the crusher 12 have

  alone, or together with other impurities, to form agglomerates, but these can be extracted

  without difficulty from the mill, with the help of the dilu-

  tion. The centrifugal classifier is designated by 1 on

  In this classifier, a rotor 2 rotates around

  turn of a horizontal axis in front of a sieve 3 essential-

  plan separating a dough extraction chamber

  completed 8 of the rest of the tank volume In this classi-

  The impurities of low weight are concentrated in the core of this flow and the impurities of high weight are concentrated on the peripheral wall with reference to the radial direction. These impurities can also be removed separately. of these areas, which is particularly the case for the heavy fraction.

  is evacuated by the line 10 At the center of the classification

  tor, that is to say in the core of the turbulent flow.

  In this connection, the tube 4 allows the evacuation of the fraction enriched in light products. Coaxially, this tube 4 is provided with another tube 5 through which dilution water can be supplied to In the vicinity of the rotor range Since the feed line 15 can be introduced by batch feeds suspensions of relatively high concentration fibers, for example equal to 12%, is brought by the dilution water concentration

  average in classifier 1 to an approximate value

equal to 5% or less.

  It is then advisable to bring the pipe 15 on the front side to the classifier and to introduce the

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  practically in the axial direction in the ear

  As shown in the figure, the recovery paper feedstock is then disintegrated with a high consistency and to a large extent the passage of the vortex flow through suspension zones is avoided.

  Thus, high consistency fibers are formed.

  thus a relatively homogeneous vortex flow.

  By the turbulence tubing 7, which is a cylinder

  hollow shaft mounted in the center of the rotor 2, the core of the

  swirling up in light products

  (leaves) is particularly marked.

  As shown, it is advisable to evacuate from the classifier the fraction enriched with light impurities

  by the axial tube 5 The extraction of the finished paste not-

  Throughout the sieve is carried out from the finished dough chamber through line 8. For further details about the extraction of the various fractions, reference will be made

  to the British patent mentioned above.

  To complete the mode of operation according to the invention, it is necessary to mention again what

  Valves 35 and 24 are suitably and neces-

  The frequency of operation of the valve 24 for the relatively pure product with a relatively lower concentration and less than 10 or 8% is accordingly higher than the operating frequency of the valve. Valve 35 In addition, the section of the pipe 15 is also larger than that of the pipe 14 The operation of the valves then takes place according to a timed command according to known methods The appropriate devices for this command as a function of time are relatively economical, and also safe operation It follows that the mode of operation according to the method according to the invention has no 2.52969 g 3 kind of difficulties The control has no reason to be

  than in a relative measure and can be automated.

  In total, it is possible to obtain in accordance with

  a recovery paper processing method, this method being very simple, safer operation

and more economical.

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Claims (1)

A process for treating recovery paper by disintegrating and suspending it in a grinder (12) at a high concentration and using a vortex flow formed in a device (centrifugal classifier 1) having a closed vessel which essentially has a form of revolution by a rotor (2) essentially arranged as a paddle wheel, a fraction enriched in heavy products (10) being extracted on the radial edge of the flow and a dough fraction finite (8) being extracted at the axial end of the flow where is mounted the rotor which produces this vortex flow, via a sieve (3) closely adjacent to the rotor, the average concentration in the vortex flow being between 3.5 and 7%, characterized in that a part of the suspension, enriched with detritus, if appropriate slightly diluted, is a state which does not allow pumping, with a concentration greater than 8%, without sieving, directly and by batch charges from the mill (12) to the vortex flow, into which additional dilution liquid is introduced. (5). Process according to claim 1, characterized in that the other part of the diluted slurry (12) is also sent to the vortex flow (1). Process according to either of Claims 1 and 2, characterized in that the dilution liquid (5) is introduced into the core of the swirling flow (1) or, at least, in the immediate vicinity. Process according to any one of Claims 1 to 3, characterized in that the dilution liquid is sent close to the rotor of the vortex flow device (1). 252k 593   Process according to any one of the claims   1 to 4, characterized in that the feeding of   the suspension in the vortex flow to the ex-   axial end of this flow farthest from the rotor (2).   Process according to any one of the claims   1 to 5, characterized in that, by means of dilution water, a fraction extracted from the mill (12) is passed through a screen (18) disposed below the rotor (16) of the mill, has a consistency for pumping, it is extracted by batch feeds and sent to swirling flow -   ) Vortex flow apparatus for carrying out the process according to any one of   Claims 1 to 6, characterized in that a tube of   of dilution water (5) is introduced into the vortex flow apparatus (1) coaxially to a tube   (4) provided for a fraction enriched with   light purities in the core of the whirlpool flow- nary.   ) Vortex flow apparatus according to   claim 7, characterized in that an opening of   unique product is arranged on the apparatus at   swirling flow (1) on its opposite front face   removed from the finished dough (8).   ) Vortex flow apparatus according to   claim 8, characterized in that the evacuation tube   (4) and the feed tube (5) are arranged   axial direction along the longitudinal axis of the swirling flow.