FR2908058A1 - Agitator for pulper, has plates occupying, in projection along plane perpendicular to axis, surface with diameter greater than specific times of diameter of tank, where plates form blades each fixed along given blade angle around shaft - Google Patents

Abstract

The agitator (3) has a vertical drive shaft (8) driven by a driving unit (7) along a vertical axis. A set of plates forms blades each fixed along a given blade angle around the shaft, where the angle of each plate has same orientation and ranges between 3 and 20 degrees. The plates occupy, in projection along a plane perpendicular to the axis, a surface having a diameter (DC) greater than 0.20 times of the diameter of a tank (2). Independent claims are also included for the following: (1) a method of pulping by mixing a fiber with water (2) a repairing method carried out after wear of an agitator.

Description

The present invention relates to a pulper turbine, designed to

  be placed in a tank, and having a drive shaft along a vertical axis Z adapted to be driven by drive means.

  The invention further relates to a method of pulping. The invention also relates to a method of repairing a pulverization device. The present invention is in the field of the paper industry.

  The invention relates more particularly to the reuse of cellulose fibers from recycled paper or virgin pulp called cellulose. It also concerns the treatment of special fibers, in particular plant fibers, such as tobacco.

  This re-use is possible provided that a complex process of aqueous resuspension of these fibers is used, with multiple purifications of the paste obtained, in order to remove all undesirable elements, such as ink, staples, adhesives, sand, or whatever.

  This process involves an essential step which is that of the pulpage, which consists of mixing the material to be treated with water, to allow the resuspension of the fibers, and the subsequent treatment of the pulp. The material to be processed is poured into a vat of a pulper. Water, as well as chemicals and / or additives, are added to facilitate the suspending or stalling of inks, or the bleaching of fibers or the like. In the particular case of cellulose, the treatment is very fast, because there is no contaminant, the pulper is used for suspending the pulp before being sent to a refiner for the improvement of its mechanical characteristics. The assembly is stirred by a turbine, consisting of a rotating assembly at the bottom of the tank.

  The parameters of pulpage (shape of the turbine, speed of rotation, duration of the pulpage, sequence of pulpage) are very variable depending on the nature of the recycled raw materials, the concentration of pulping, and the destination of the pulp constituted by the fibers. plumped. Various types of pulper are known, differing essentially in the morphology of the turbines employed. They are mainly distinguished by their kinetics of defibration. The pulped mass comprises water, separated fibers, and paper pellets whose size decreases as a function of the duration of pulping and the energy consumed.

The energy consumed to achieve a given residual pellet rate is characteristic of the performance of the pulper. FR-A-2 544 756 discloses, in a cylindrical vessel, a helical turbine with a vertical axis causing the paste to descend to the bottom of the tank where it is pushed in an upward centrifugal movement by the specific geometry from this background. This system, adapted to the high concentrations, proves a kinetics of defibration or depastillage of average performances.

FR-A-2 169 240 describes, at the bottom of a cylindrical vessel, a finned turbine whose lower faces are sharp. Such a device is limited to low pulping concentrations, up to about 6%, and has a kinematic poor grinding.

Vertical helical screw systems are still known in the upper part, feeding a second turbine part devoted to the rising of pulp in the tank, as well as to the section, arranged at the bottom of the tank. This system is effective only for a water-paper mixture rather liquid (concentration of the order of 5%), but does not work well with higher concentrations (12 to 25%). Yield, although improved compared to previous systems, remains low. Various attempts have been made to further reduce energy consumption during pulping. Some displace the problem, by performing, upstream of the pulpage, a dipping of the balls, or an injection of steam into a chamber through which a worm passes. Such solutions increase the cost of investments, the occupied space, and do not reduce the overall energy consumption.

Document WO / 2001/073194 also discloses a device in which the tank forms a discharge hopper and develops helically. The realization of such a tank is very expensive and represents a high investment. As described, the known devices of the state of the art make use of helical turbines, of so-called helico type, of complex shape. Their helicoid shape ensures the movement of the paste in the tank, thanks to a centrifugal pumping in the lower part, which by suction causes the upper dough to descend to the bottom of the tank by the center and pushes the dough thus sucked up the tank, periphery. The suspension of the fibers is obtained by friction of the recycled papers with each other, thanks to this displacement but also thanks to the contacts between the papers and the rotating edges of the turbine. These ridges are highly worn due to these contacts. These ridges are also sometimes equipped with teeth to increase the impact on hard-to-defibe papers such as Wet-Resistant (Wet). Their realization in foundry, or in mechano-welding, is extremely expensive because of the left surfaces, and requires a long supply period, of the order of several months. In particular foundry versions, in large dimensions (height close to or greater than 2 meters), require the implementation of expensive foundry models, and very large quantities of sand and metal. Repairs are also delicate and expensive, as well as the reloading of anti-wear deposit such as cobalt alloy, stellite or the like, often necessary to compensate for wear.

The helical shape imparts to the dough a mixed motion consisting of an axial velocity at the center from top to bottom of the vessel, and a tangential velocity in the direction of rotation of the turbine. Thus the dough mass is rotated by the turbine, which represents an energy expenditure that does not accelerate the speed of defibration.

Depending on the type of dough to be worked, the user wishes to be able to install turbines of different size and morphology in the vat, depending on the kinetics of defibration that it is desired to apply to the dough. The cost of turbines in this helicopter technology is a brake on this versatility.

Teeth are cut on the edges of the propellers, and oriented at an angle like the latter. This arrangement is not optimal for accelerated shredding. A mixed solution has been developed, in the form of a so-called helidisc type turbine consisting of spiral screw type spirals, of large diameter, at the top, and pumping vanes at the bottom of the tank. During the rotation of a helisdisc turbine, the turns ensure the movement of paste from top to bottom through the center of the tank, and the blades ensure the return of paste from bottom to top at the periphery of the tank by overpressure. The defibration kinematics are better than those of a helicopter type turbine. However, the manufacture of large diameter turns is, again, difficult and expensive. In addition, such turbines are monobloc, which makes their assembly difficult on the pulper. Pulper turbines, in high concentration (15 to 25%) water-paper blending applications, are usually mounted in one piece, and constitute a large assembly that must be installed in the tank on the spindle shaft. training. In small installations (less than 12m3) it has been imagined to fix the turbine on a plate itself secured to the drive means. However such a plateau, large size, remains an expensive additional piece.

Other larger installations include a rod integral with the drive means, and passing through the turbine from one side to the other; this rod is also expensive, and difficult handling, which complicates singularly the maintenance operations. Indeed, the turbine of a pulper generally comprises a tubular central shaft engaged on the drive means of the pulper. The difficulty lies in the maintenance and dismantling of such a set. Being in a very corrosive environment, it is not uncommon for the tubular shaft of the turbine to seize on the drive means of the pulper, the release being obtained by heating from the outside of the shaft. turbine. However one can not be satisfied with a localized heating, and, to obtain the desired effect, it would be necessary to heat the shaft of the turbine over all its height, which is then impossible.

In order to improve the shredding effect, which is necessary for good dough pulping, it is common to arrange teeth at the periphery of the vanes that the turbines comprise. However, these teeth are, in this case, due to the configuration of the blades themselves, inclined relative to the horizontal, or even in almost vertical configuration. So that these teeth have a lower efficiency and especially create impurities training obstacles such as son, which can not be released from these teeth, cause accumulation effects.

In summary, known pulping installations have a non-optimized defibration kinematics and are not very versatile. Both investment and maintenance costs are important, and replacement or repair times require costly components to be in stock.

The object of the invention is to overcome the drawbacks of the state of the art by proposing a device with significantly improved defibration kinematics compared with the state of the art because it is low in energy consumption and low in manufacturing cost. Easy mounting, low maintenance cost, and great versatility in applications.

For this purpose, the invention relates to a turbine for a pulper, designed to be placed in a tank, and comprising a drive shaft along a vertical axis Z adapted to be driven by drive means, characterized by the it comprises, at least in its upper part, at least one or a plurality of blade plates each reported at a wedging angle given around said vertical drive shaft, this wedging angle a of each of the plates having the same orientation.

According to another characteristic of the invention, said plates follow each other, more distant from the bottom of the tank, in which is intended to take place said turbine, closer to the bottom of said tank, according to one or more discontinuous arrangements of the type. spiraloid such as one or more threads of a screw. According to another characteristic, the plates farthest from the bottom of the tank, in which is intended to take place said turbine, occupy, in projection in a plane perpendicular to said Z axis, a surface of diameter 20 capable, centered on said Z axis , less than that corresponding to the plates closest to the bottom of said tank. According to a particular characteristic of the invention, said plates are flat.

According to still another characteristic of the invention, said upper part defines a first turbine part, comprising removable mounting means designed able to cooperate with conjugated mounting means associated with a second lower turbine part, which is defined adapted to cooperate, by means of suitable fastening means, with drive means, this second lower turbine part being further provided with one or more pumping vanes. The invention further relates to a method of pulping.

The invention further relates to a method of refurbishing a pulverizing device.

Other characteristics and advantages of the invention will emerge from the following detailed description of non-limiting embodiments of the invention, with reference to the appended figures, in which: FIG. 1 is a diagrammatic representation of FIG. in section, a pulper provided with a turbine according to the invention; - Figure 2 shows, schematically, partially, and in perspective, a top plate of a turbine according to the invention, fixed on the drive shaft; Figure 3 is a schematic top view corresponding to Figure 1; - Figure 4 shows, schematically, partially, and in top view, a plate of the upper part of a turbine according to the invention; FIG. 5 is a diagrammatic, partial view in plan view of a blade of the lower part of a turbine according to the invention. The present invention is in the field of the paper industry.

The invention relates more particularly to the reuse of cellulose fibers originating from recycled paper or from virgin pulp, referred to as cellulose pulp, in the latter case. It also concerns the treatment of special fibers, in particular plant fibers, such as tobacco.

The aqueous suspension of these fibers, with multiple purifications of the paste obtained, in order to remove all undesirable elements, such as ink, staples, adhesives, sand, or other, is performed during an operation. called pulping, which consists of mixing the material to be treated with water, in order to allow the resuspension of the fibers, and the subsequent treatment of the pulp. The material to be reprocessed is poured into a tank 2 of a pulper 1. Water, as well as chemicals and / or additives are added to facilitate the stalling of the inks, the bleaching of the fibers, or the like. The whole is stirred thanks to a turbine 3.

This turbine 3 is rotatable about an axis Z, which, in a preferred embodiment, is vertical. This turbine 3 has the function of stirring the mass of dough, by the combination of a vertical movement, preferably down to the bottom 6 of the tank 2, and a horizontal movement, preferably centrifugal, within the 2. The dough is thus permanently brought into contact with the turbine 3, which allows a thorough stirring, and a defibration of the material.

In a preferred embodiment, as can be seen in FIG. 1, the turbine 3 comprises a turbine upper part 4, which makes it possible to generate the vertical movement of the dough. This upper part 4, as can be seen in FIG. 1, may be mounted integral with a lower turbine part 5, designed to push the paste on the periphery of the tank 2. This embodiment is preferred for reasons of simplicity and cost of construction. In this case, the lower part 5 of the turbine is designed capable of cooperating, by means of suitable fastening means, with drive means 7. Preferably, the upper part 4 of the turbine comprises means for mounting, preferably removable, designed adapted to cooperate with conjugate mounting means associated with the lower part 5 of the turbine. In a preferred embodiment, this connection is made by bolting. But it will be understood that it is possible, without departing from the spirit of the invention, that the pulper 1 has upper parts 4 and lower 5 independent turbine 3.

The known embodiments of the state of the art, comprising an upper portion of turbine 3 of the so-called helico type with a helicoidal shape have the characteristic of driving the entire mass of paste in a rotary movement at the level of the upper part 4 of the turbine, which is added to the vertical movement and horizontal movement described above.

However, this rotation of the entire dough mass does not provide any particular performance with respect to pulp pulping, but on the other hand the partial rotation of the mass with the turbine 3 consumes a considerable amount of energy. which does not produce a positive effect on the speed of defibration, and which alters the kinetics of defibration of the pulper 1. This kinetics of defibration can be evaluated by the ratio between the amount of treated material and the energy consumed. It has therefore been imagined, in an inventive step, to develop a particular arrangement of the turbine 3, and in particular of the upper part 4, in order to allow the circulation of the paste mass in a substantially radial manner with respect to the Z axis of the turbine 3, while benefiting from a flow of substantially spiral paste in the vicinity of the turbine 3, and this new design has another purpose to overcome very expensive embodiments, such as foundry or furthermore, the mechano-welding of left-handed shapes with a changing profile, and of making such a turbine 3 from simple components, easy to assemble and exchange.

For this purpose, it has been imagined, according to the invention, to constitute the upper turbine part 4 in the form of a plurality of plates 9, or at least one plate 9. These plates are fixed on a shaft 8, in rotation about the vertical axis Z, in the particular embodiment as shown in FIGS. The plates 9 are arranged generally radially and attached to the drive shaft 8 by simple fastening means (screwing or welding, or other), and preferably maintained spaced from this shaft 8 rigidly by gussets 10 , or the like. As can be seen in FIG. 2, each of the plates 9 is pivoted, in the manner of a turbine blade, with respect to a half-axis OY orthogonal to the axis Z. This half-axis OY has its origin on the Z axis at a point O and passes through a point M of the plate 9 concerned. The plate 9 is pivoted at a rotation angle α, called the angle of registration, which the normal vector makes at its point M, and oriented in the same direction as a vector parallel to the Z axis and oriented in the direction of the Z axis, with the latter. The wedging angle a of each of the plates 9 has the same orientation: all the plates 9, which are attached around the same shaft 8 comprise a leading edge 11. This leading edge 11 is oriented, for all the plates 9, on the same side with respect to the Z axis. This leading edge is preferably progressive, and in particular in the form of a circular arc or a straight edge leaking. For each of the plates 9, this leading edge 11 is situated on the same side with respect to a vertical plane P passing through the Z axis and by the local Y axis passing through a point M of the median zone of said plate. In short, if one creates, around the point of attachment of each plate 9 on the shaft 15 8 a direct orthonormal trihedron, the leading edge 11 of all the plates 9 mounted on the same shaft 8 is in the same quadrant than the others. This arrangement explains that, for a given direction of rotation of the axis 8, all the plates 9 tend to move the dough in the same direction.

In this connection, it should be noted that, even if a downward movement of the dough is preferred, an upward movement of the dough resulting from the rotation in the opposite direction of the shaft 8 can also suspend the elements of the dough. the dough, and participate in the desired pulping process. This may lead to choosing for the plates 9 a substantially symmetrical profile so as to be able to operate in reverse mode. The plates 9 follow one another, from the farthest from the bottom 6 of the tank 2 to the nearest, in one or more discontinuous arrangements of the spiraloid type such as one or more threads of a screw. The plates 9 thus constitute, around the drive shaft 8, a pseudo-turn, which allows the flow of the spiral paste in the vicinity of the turbine 3, without causing rotation of the entire mass of dough.

This effect is obtained by the presence of gaps between the different plates 9, and thus makes it possible to economize the energy corresponding to the rotation of the entire mass of dough. In sum, the succession of plates 9 thus arranged makes it possible to impart to the dough a substantially vertical movement, without, however, generally rotating it. The assembly of the plates 9 on the drive shaft 8 can be performed by simple means: embedding in a groove, welding, screwing, or other. It then suffices to give the contact zone between each plate 9 and the shaft 8 the proper inclination to provide the required angle of rigging. In a preferred application, the wedging angle a is between 3 and 20. In a particular application, all the plates 09 have the same angle of registration a. It is not necessary to form these plates 9 in a coil, which makes it possible to greatly reduce the cost compared with the very expensive solutions known in the state of the art. This advantage makes it possible to repair a worn turbine by simply dismantling or desoldering these plates, and installing new plates. In this regard, if it is possible to use plates rolled sheet along the axis OY, inexpensive execution, approaching the profile of a hydraulic blade or engine, it is still much less expensive to use flat 9 plates. The cost saving comes from the cost of the plates 9 themselves, and their attachment to the drive shaft 8, which is greatly simplified. In a preferred embodiment, as can be seen in FIG. 1, the plates 9 disposed opposite the bottom 6 of the tank 2 have a diameter capable of DC (ie the diameter that a centric disc would have on the Z axis and perpendicular to the latter, extending so as to cover the point of the plate 9 farthest from the axis Z) less than those arranged more near the bottom 6 of the tank 2. Thus, in the case of a vertical Z-axis embodiment, a space is provided between the periphery 2908058 12 of the tank 2, and the zone farthest from the bottom 6 of the tank 2 of the upper part 4 of the turbine, a space which allows the material to be recycled to be dumped into the tank 2, without the risk of damaging the turbine 3 by shocks during the fall of this raw material in the tank 2 during filling of the latter. To obtain a good circulation of the paste in the pulper 1, the capable diameter DC of the plates 9 must be large enough; in a preferred application, it is at least 10 to 0.20 times the diameter of the vessel (or the smallest transverse dimension thereof). This provision is important for obtaining a good cinematic defibration. The choice of the size of the plates 9 makes it possible to stir and pulp a much larger volume than a simple stirrer would do. In a preferred embodiment, as visible in Figure 4, each of the plates 9 covers, around the vertical shaft 8, an angular sector R between 90 and 200. In a particular embodiment, as visible in FIG. 3, at least a first plate 9, in projection along a plane perpendicular to the axis Z, partially overlaps with at least one other plate 9 which is separated from the first in the direction of the axis Z. It will be noted, again, that, according to the applications, it is possible to build quickly and cheaply an upper portion 4 turbine consisting, as the case, a small number of plates 9 of large dimensions in a preferred embodiment, or a large number of plates 9 of reduced dimensions, or to variegate plates 9 of large and small size. The simplicity of the plates 9 makes it possible, at a lower cost, especially in the planar execution, to size them on demand. The change of their arrangement, as well as their orientation (angle of setting a) is also very easy and cheap.

In short, the turbine 3 according to the invention allows rapid reconditioning, to adapt to the pulpage of materials 2908058 13 very different natures, which gives it a versatility unknown in the prior art. It will be understood, furthermore, that the maintenance of such a turbine is greatly improved by the ease of disassembly, for repair or possible replacement, of each of the plates 9. In fact, the phenomena of abrasion, but also accumulation under the hooking effect of son or body not or badly shredded, quickly damage the pulping turbines. To prevent such accumulation phenomena, the plates 9 have, at their leading edge 11, a particular profile which prevents the attachment of contaminants in the form of wire (metal scrap, plastics in particular).

In a preferred embodiment, as visible in FIG. 4, this profile is scalable and such that, at each point M 'of the leading edge 11, the tangent to this profile defines a positive angle θ. The angle 8 is defined as the oriented angle comprised from a plane passing through the Z axis and by this point M '20 on the one hand, towards the tangent to the profile oriented in the direction of the distance from the Z axis, on the other hand, measured in the opposite direction to R direction of rotation, as visible in Figure 4. In particular embodiments, the profile may take the form of a circular arc, or a straight edge fleeing.

In order to best shred the raw material poured into the pulper 1, the plates 9 may comprise, at least in their peripheral zone furthest from the Z axis, a toothing 13. This toothing 13 comprises a leading edge 15 which defines, at a point M ", in the direction opposite to the direction of rotation R of the shaft 8, a positive angle 5. The angle 5 is defined as the oriented angle comprised from a plane passing through the Z axis and by this point M "on the one hand, towards the tangent to the profile of the toothing 13 at this point 35 M" oriented in the direction of the distance from the Z axis of other 2908058 14 part, measured in the direction opposite to the R direction of rotation, as visible in FIG. 4. Preferably, this toothing 13 extends, as the case may be, in a plane perpendicular to the Z axis, or along a surface tangent to that The angle 5 is preferably greater than 30, for example a value of about 60. In an embodiment it is preferred, the toothing 13 has an asymmetrical V-shaped profile.

Preferably, but in no way limiting, the toothing 13 is held on the plates 9 by conventional fixing means, such as screwing, welding, or other. The almost flat orientation of the teeth constituting the toothing 13 gives them a very high efficiency to accelerate the defibration of any sheet or piece of recycled paper that would not be carried in the downward movement of the dough. This efficiency is also very good with regard to difficult papers such as REH (wet-resistant) sheets.

The upper turbine part 4 is, in a preferred application, as can be seen in FIG. 1, demountably assembled with a lower turbine part 5. This lower part 5 is, as shown in FIG. 1, in a nonlimiting manner, in cooperation with drive means 7, such as a motor shaft. The lower portion 5 of the turbine preferably comprises one or more pumping vanes 12, which have the effect, during its rotation, of driving the dough towards the periphery of the vessel.

The upper part 4 and the lower turbine part 5 are preferably assembled to one another by bolting. The turbine 3 is easily removable, and the maintenance operations on its upper part 4 and on its lower part 5 can be disjoint. In the event of an incident, for example seizure between the driving means 7 and the lower turbine part, the debonding, or even the cutting of the bolts in extreme cases, allows convenient access to the lower part. 5. It is then possible to extract it from the tank 2 by the implementation of cylinders, or by heating in the vicinity of the drive zone. It will be noted, again, that a dismountable turbine 3 thus constituted of two parts, upper 4 and lower 5, does not require an additional mechanical plate, the lower part 5 fulfilling this function. The turbine 3 according to the invention is therefore suitable for all sizes of pulper installations 1, and saves the cost of such a tray. The shredding of the paste, after the evolution thereof in the zone of the upper part 4 of the turbine, is advantageously continued at the lower part 5 of the turbine. For this purpose, the blades 12 may be equipped, as can be seen in FIGS. 1, 3 and 5, with teeth 14. Such toothing 14 extends, as the case may be, along at least one horizontal plane perpendicular to the Z axis, or in at least one surface perpendicular to that of said blade 12. Preferably, this toothing 14 has a special profile at its leading edge 16 in the direction of rotation R of the lower portion 5. This special profile is scalable, and such that at each point M '' of the leading edge 16, the tangent to the profile defines, in the direction opposite to the direction of rotation R, a positive angle * .The angle * is defined as being the oriented angle included from a plane passing through the Z axis and this point M "" on the one hand, towards the tangent to the profile of the toothing 14 at this point 30 m "" oriented in the direction of the distance from the Z axis on the other hand, measured in the direction opposite to the direction R of rotation, as visible in FIG. 5. This special profile p This prevents the hooking of threads present in the bowl 2 on the toothing 14 and prevents undissolved paper from accumulating on the toothing 14, thereby stopping the kinetics of defibration. With the special profile, any wire 2908058 16 which touches a tooth of the toothing 14 is automatically discharged during the rotation of the turbine 3. In a preferred embodiment, the toothing 14 has an asymmetrical V-shaped profile.

Preferably, as can be seen in FIGS. 1 and 5, the vanes 12 are equipped with a plurality of teeth 14 that are substantially parallel to one another. In the same way as for the upper part of the pulper, the blades 12 can be designed to work in reverse mode, they are advantageously curved to bring the dough more easily towards the center. Of course, the invention is not limited to the examples illustrated and described above which may have variants and modifications without departing from the scope of the invention.

Claims (12)

  1. Turbine (3) for a pulper (1), designed to be placed in a tank (2), and comprising a drive shaft (8) along a vertical axis Z adapted to be driven by drive means ( 7), characterized in that it comprises, at least in its upper part (4), at least one or a plurality of plates (9) forming blades each reported at a wedging angle (a) given around said shaft. vertical drive (8), this wedging angle (a) of each of the plates (9) having the same orientation, and in that said plates (9) occupy, in projection along a plane perpendicular to said Z axis, a surface whose capable diameter (DC), centered on said Z axis, is greater than 0.20 times the diameter of said vessel (2).   2. Turbine (3) according to the preceding claim, characterized in that said plates (9) succeed one another, farthest from the bottom (6) of said tank (2), wherein is intended to take place said turbine (3). ), closer to the bottom (6) of said vessel (2), according to one or more spiraloid type discontinuous arrangements such as one or more threads of a screw.   3. Turbine (3) according to one of the preceding claims, characterized in that said wedging angle 25 (a) is between 3 and 20.   4. Turbine (3) according to one of the preceding claims, characterized in that said plates (9) are flat.   5. Turbine (3) according to one of the preceding claims, characterized in that each of said plates (9) covers, around said vertical shaft an angular sector (p) between 90 and 200.   6. Turbine (3) according to one of the preceding claims, characterized in that at least a first 35 of said plates (9), in projection in a plane perpendicular to said Z axis, comes partially in 17808058 18 recovery with at least one of said plates (9) which is spaced from the first in the direction of said Z axis.   7. Turbine (3) according to one of the preceding claims, characterized in that the plates (9) farthest from the bottom (6) of said tank (2), wherein is intended to take place said turbine ( 3) occupy, in projection in a plane perpendicular to said Z axis, a surface of diameter capable (DC), centered on said Z axis, less than that corresponding to the plates (9) closest to the bottom (6) of said tank (2).   8. Turbine (3) according to one of the preceding claims, characterized in that said plates (9) comprise, at least at their leading edge (11) in the rotational service direction R of said drive shaft. (8), a profile 15, particularly evolutive, such that at each point M 'of said leading edge (11) the tangent to said profile defines, in the direction opposite to the direction of rotation R of said shaft (8), an angle (8) positive with respect to a plane passing through the Z axis and said point M '. 20   9. Turbine (3) according to one of the preceding claims, characterized in that said plates (9) comprise, at least in their peripheral zone furthest from said Z axis, a toothing (13) having a leading edge. (15) which defines, in the direction opposite to the direction of rotation R of said shaft (8), a positive angle (5), and in that said toothing (13) extends, as the case may be, in a perpendicular plane to said axis Z, or along a surface tangent to that of said plate (9), and in that said angle (5) is greater than 30   10. Turbine (3) according to one of the preceding claims, characterized in that said upper portion (4) defines a first turbine part, having removable mounting means designed adapted to cooperate with the associated mounting means associated with a second lower turbine part (5), which is defined adapted to cooperate, by means of suitable fastening means, with driving means (7), this second turbine lower part (5) being provided elsewhere one or more pumping vanes (12).   11. A method of pulverizing by mixing fibrous material to be reprocessed with water, for the resuspension of its fibers, according to which: the material to be treated is poured, with water as well as chemicals or / and additives in a tank of a pulper provided with a turbine according to one of claims 1 to 10 10 - the whole is stirred through said turbine.   12. A method of repair after wear of a pulper turbine according to one of claims 1 to 10, characterized in that one dismantles or desoude the plates (9) 15 worn, and they are replace with new plates (9).